Rapid spool turbo with on-board compressed air in exhaust
 

Hello all, I am posting some information on the system I built to rapidly spool the turbo using on board compressed air into the exhaust manifold. My first time posting so please forgive if I break a rule or two. I normally don't post anything on a public forum however I posted a couple videos showing the system in action and many people have contacted my son asking questions about it on facebook thinking he was me since we share the same name. I dont do facebook but have spoken with Pat and Lars on this forum so thought I would post the system details here for others to duplicate if they want.

First a little info on the car. Its basically a junkpile 99 miata that I like to tinker on. the engine is a 1.8l with 1mm over wiseco pistons, chinese h beams rods and arp hardware. Fueling is e85 with id1000 injectors and walboro e85 pump. I use lucas ethanol treatment to help mitigate water absorption and corrosion. I also use topend lube since its a dry fuel. Turbo setup is a chinese gt3076 clone at around 30lbs boost. Tranny is a jatco e4n71, Mazda calls it a nc4ael. Its highly modded and built by me with good bands and frictions with 2 extra frictions in the clutch pack used for third gear. The engine and turbo setup has been together about three years and the tranny maybe 2 years. I beat on this regularly. Rear tires on the car currently are nitto extreme drag 245/50/16 radials. It took some serious hammer action to fit these puppies...

Now to spool shot setup. First I will have to say if you have a good size turbo this system will mainly be beneficial for drag racing or the occasional hit on the street, and most benefit with an automatic tranny. A manual transmission car will be to the left of the compressor surge line with this system on a large turbo at lower rpms. The torque converter of an automatic allows the rpms to blow through the range where surge happens very quickly so its not really and issue. The larger turbos take a lot of air to kick start the spool process rapidly and low rpm. I use a 5 gallon tank mounted in the trunk. In one shot the pressure drops from 140psi to around 90 and system has to charge again for next shot. This is also the reason you would want a belt driven compressor over a 12v system. I initially tried using a viair style 12v compressor. It was loud and took forever it seemed to charge the tank. I switched to a sanden 508 ac compressor I modified to pump air instead of refrigerant and never looked back. It charges the tank quickly and quietly. Volvo gets away with a 12v compressor since they are only charging about a 1 gallon tank, which works for them as they are spooling a tiny turbo. I use some maps on a fic6 to have a tuneable time in which the spool shot solenoid fires. I also use some of the fic maps to control and tune the torque converter lockup.
Please excuse the rough draft drawings. These are my initial drawings when I was designing the system, but they are legible enough I think and they reflect the design of system the way it is now. Also please overlook the cobbled together nature of the setup. My initial intent was to quickly and cheaply throw this system together to test and tp re-do it in a more permanent fashion, however it worked so well I never got around to it and just left it as is.

https://cimg6.ibsrv.net/gimg/www.mia...2a95cfecfa.jpg
This is the basic wiring configuration. I use the switch to arm the system or to disable. you only want this thing active when you need it, otherwise you'll be shooting air at every stoplight. The hobbs switch I use is is a 15psi nc.

https://cimg1.ibsrv.net/gimg/www.mia...41f27f9da9.jpg
This is the basic plumbing setup. I maintain minimum 1/2" from tank to manifold.

How does all this perform? I think it works very well. I have a couple old youtube videos. one has already been posted on Pats compound turbo thread, but Ill post again along with a 0-60 test using the performance expert phone app
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Here is a picture of a 1/8 mile test I did with the dragy device. For those unfamiliar with dragy its a divice that uses high speed gps and a built in accelerometer. For 1/8 mile and 1/4 mile testing the software tries to emulate dragstip timers be factoring rollout and averaging the last 66' trap speed. Many people have tested this while at the strip and found this device extremely accurate, even more so than vbox apparently.
https://cimg9.ibsrv.net/gimg/www.mia...d4cf4459b7.png
I know the 60' is a little soft, but keep in mind this is on the street and not a prepared strip. In fact I always start in 2nd gear and still have to feather the throttle a bit for a couple seconds. Check out the trap speed though, thats indicative that its making decent power.

Below are a few pics of engine and car to further see setup. Again, I know its a hoopty, but I've always had a soft spot for sleeper builds....

https://cimg9.ibsrv.net/gimg/www.mia...5ae2935d29.jpg
pipe into manifold


https://cimg7.ibsrv.net/gimg/www.mia...e151148e45.jpg
sanden 508 compressor


https://cimg6.ibsrv.net/gimg/www.mia...c97c88ac8d.jpg

Sweet, love outside to box projects.

Right on man, that's a pretty novel idea. I'd think some folks may prefer this to misfiring or nitrous for spooling the turbo due to being more gentle on the system.

Just to add a little more information to help people wrap there minds around the spool shot system.

The 15psi nc hobbs switch in wiring diagram is plumbed to the intake manifold. The relay disables compressor operation while the spool shot solenoid is open. The tuneable signal is 12v that i normally set at 2800 rpm, at full throttle and above 13.5psi absolute (just a little below atmospheric pressure). So in operation the relay is energized anytime the previous mentioned conditions are met when the system is enabled. The compressor will not come on when this relay is energized. The hobbs switch opens after 15psi to close the spool shot solenoid to preserve tank pressure since the turbo spools on its own after that anyways.
The way I use this during a test run is brake boost to about 2500rpm to build a little speed in the turbine then release brakes and full throttle, but feathering throttle slightly as necessary. If I hold brakes too long while going full throttle spool shot will happen before brake release and blow tires off badly. I always start in 2nd gear as thats proven quicker for my setup in testing. So a 1/8th mile run just has one shift to third gear. With my tall tires second gear is good to almost 80mph and a little over 80 if I allow the converter to lock, but I usually only allow lockup in 3rd and 4th gears. If I allow converter to lock in 2nd tires will break loose at higher speeds so I keep it disabled for 2nd. Data shows maximum g's usually occur somewhere between 30 and 45 mph depending on traction. Operating this way I hope will preserve my axles and driveline as torque multiplication to the wheels will be much less off the line than if I start in first and tires happen to hook, I may give up a tenth or two in et though but thats ok with me for the time being.

very cool setup :D

Super cool stuff. Thanks for sharing.

Didn't read though everything, wouldn't this throw off your AFRs?

It would throw off the measured AFRs but not the actual AFRs unless you had the ECU set to adjust according to measured. And you would never knowingly set it that way once installing a system like this.

The spool shot only happens at full throttle when its enabled and called for so most ecu's are in open loop and ignore the o2 sensor. You just tune your engine as you normally would without it. When its being used when your gauge shows lean the engine is actually not lean because the air does not run through the engine, just into the exhaust manifold. Plus my testing data shows the spool shot only last for 5 to 6 tenths of a second anyways to kick start the spool process. So for that 1/2 second when its operational it has no significant effect other than a tremendous reduction in spool time. I run a china clone gt3076 and without this system my car is a dog on the bottom end as spool takes forever. With this system, unless i blow the tires off, I usually get somewhere in the mid 3 second range 0-60 on the street as tested on both nitto drag radials and also M&h racemaster bias ply dot drag tires. I have been testing with g-tech (older version), the performance expert app., and the dragy device. The dragy has been independently proven extremely accurate to dragstrip timer data. In my testing all the systems report back very similar results for 0-60 but for 1/8 mile testing the dragy will report back a lower trap speed since the software for it reports an average speed over the last 66' to emulate the dragstrip speed trap timers, whereas gtech and performance expert show speed at end without averaging.

The only real potential drawback I can see is compressor surge for people with larger turbos and manual transmissions. As I mentioned previously its not really problem for automatic cars since the torque converter allows the rpm's to rapidly climb above the area were surging may happen unless you have a very tight converter.

Just did another 1/8th mile test with dragy device. Got my new best time with it. If anyone is looking for a fast responsive gps based device to test acceleration, this tool looks to be a viable alternative to the v-box system for much less money.
https://cimg8.ibsrv.net/gimg/www.mia...0a50672b25.png
https://cimg3.ibsrv.net/gimg/www.mia...27178ea320.png

Wow, that's quick, good trap speed too. Is that a built motor?

Yeah both motor and transmission. Many of the details are in the first post.

Very cool. Reminds me of CAS.

This is sweet! One thing I'd like to know more about is how you converted an AC compressor to an air compressor. That sounds like it could be useful for all sorts of projects. Very cool project!

Basically I did a grease conversion on the compressor. Im using the sandan 508 as are others. This link is a good start Grungles Homepage . I did a few things differently than he did though. I drilled and tapped the suction and discharge ports for npt for easy plumbing. I plugged the oil holes in the center plate as he did, however doing just this you will still get a lot of grease through the center hole where the crankshaft end and bearing pass through. So what I did to stop the grease intrusion to the top of pistons though this area was to cut and form a seal out of a thin piece of sheet metal to seal this center hole in the head gasket area. When you get the compressor apart it will make sense. Im attaching a modified picture from grungles sight to help you visualize this area.
https://cimg9.ibsrv.net/gimg/www.mia...3490e5f73b.jpg
What you want to do is seal the grease from crankcase area from reaching the top of the pistons. Many other people are also adding various oiling schemes in addition, however for me personally I did not find it necessary. I just add a few shots of grease into compressor crankcase and a quick shot of fogging oil into compressor inlet while its running maybe once every couple months. I've seen no signs of complaining from the compressor doing it this way. I have had this compressor setup like this for almost two years.

Very cool idea with the compressed air and its good to see another Jatco MX5/Miata out there its one of the best combo's for a street sleeper

The jatco 4n71 style transmission looks to have some fair potential once modified. My original intention a couple years ago was to convert to a ford c4. I even built one in advance to use. I am comfortable with the older transmissions such as the c4/c6, powerglides and th350/400 as thats what we used back in the day and guys still use them due to huge aftermarket support.... However I decided to get ahold of the jatco to get a look at the internals before I went to the trouble and expense of a c4 conversion. To my surprise the bands, frictions, drums and planetary assembly's were all very similar to the c4's, so I decided to build one up to test. Glad I did... Having a 4th gear and lockup is nice on the street. Its been in close to two years and holding 30 psi well, and Im not gentle on it.

Btw. Mr. mx5psi, The Miata you built is a sweet ride.

Just a quick update to a recent change to spool shot system. I removed the hobbs switch that was used to close spool shot solenoid after a certain boost pressure is reached and replaced it with voltage comparator circuitry and a dash mounted potentiometer so now i have fully tune-able system for both start and end of spool shot firing. The inputs for the comparator are from the pot and the map sensor. My reasoning for doing this follows.

I made some changes to turbo setup and fueling in preparation to hopefully increasing boost from the 30 psi range to closer to 40psi. I swapped the fuel pump to the walbro 525 pump since on paper it looks to be adequate for fuel supply, and also to a 4bar map sensor. I also swapped the clone gt3076 to a clone gtx3076. The gtx has a billet compressor wheel that is 1mm larger so I noticed it took slightly longer to spool to the higher boost regions than the old turbo. So I adjusted the hobbs switch setting from 15psi to maybe 24psi. After doing that the new setup hit much harder to 30psi, actually a little too hard. That got me to thinking hmmmm, wouldn't it be cool to be able to tune that parameter from the drivers seat? So that's why the change from the hobbs switch to the comparator circuit and dash mounted pot for control.
I have some testing and tuning to learn and adjust new system for best traction/acceleration but its looking promising. I've been slowing creeping the boost up a bit, now set in the 35psi range. Traction is more of a problem, even with the drag radials. However i have gotten in a couple 40-70 mph tests with the dragy to compare with previous setup. In only a couple tries I've exceeded my previous best 40-70 by 18 hundredths of a second. I know that doesn't sound like much, but for that short of a span it's actually fairly significant. Once I have it dialed in again to where I can launch from a start Im hoping to increase my 1/8 mile trap speed from 102mph to closer to 104-105 mph when testing with dragy device.

i was thinking about changing my 460 to a 525 did you upgrade wiring ? keen to see what this auto does on higher boost

I wired with 10 gauge straight from the battery to the pump through a 30 amp relay. I drilled and sealed through the pump access cover to pass wires. The 30amp relay gets fairly warm when car runs for a long time so will be swapping for a 40 amp. The walbro 525 looks like it will do the job for me but boy does that sucker pull some amps.

Do you know how much he the trans will hope without modifying it?

Hard to say .A lot would depend on the mileage and condition of what you have. Once you start adding power you will decrease the life of the clutch friction plates due to the slow/soft stock shifts but I would think roughly 200-225hp would be no problem for the jatco as used in the 91-97 miatas if its in good shape and you keep the transmissions fluid temps in check. They can easily handle much more with the proper mods, However, There is no aftermarket support for these transmissions in the states, so if you cant build it yourself it will not be cheap to have it built for power.

New best 1/8th mile test using dragy. This is on the street with nitto drag radials.
https://cimg3.ibsrv.net/gimg/www.mia...0c4e7453cd.png
https://cimg8.ibsrv.net/gimg/www.mia...4a6a04c73e.png

To answer a couple questions asked elsewhere. The solenoid valve I am using is an EHCOTECH B21V-3/4-CC-12VDC SOLENOID VALVE. It can be found on ebay for 25-30 bucks. The exhaust check valve BWD cv8 Secondary Air Injection Pump Check Valve. It can be found at oreillys. I am using a total of roughly 2 feet of 1/2" npt galvanized pipe connected to exhaust manifold to allow a little distance for cooling of pipe. The exhaust check valve is connected to the end of the galvanized pipe opposite the exhaust manifold. I then have about 18" of high temperature 5/8" id hose connected to that check valve and the solenoid valve. I did it this way to try and isolate the solenoid as much as possible from exhaust heat. You may be able to do it differently and have it work perfectly fine. This is just what I did. I used at a minimum 1/2" Id hose throughout entire system. It takes a surprisingly large blast of air to kick start spool process in a very rapid fashion if using a larger turbo, and thats in conjunction with full throttle exhaust gases since this system is only used at full throttle. Also just to reiterate, This setup is really best suited for use with an automatic transmission off the line or the occasional hits from a roll.

UPDATE....
Well I finally made it to the 1/8th mile dragstrip. I made two passes. One was a 7.08s and one was 6.91 both at 105mph. Without the spool shot these times would have been significantly slower. I also got dragy data on the 6.91 run. Im posting it as well so one can see the accuracy of that device. Its actually quite impressive how accurate. It proves to be valid for testing when a dragstrip is not available.

Keep in mind these runs were made with an ebay gtx3076 churbo, ebay cast log manifold, ebay intercooler, stock head, cams, coils and intake.


https://cimg5.ibsrv.net/gimg/www.mia...b7578117be.jpg
https://cimg9.ibsrv.net/gimg/www.mia...7e38e71d96.jpg
https://cimg2.ibsrv.net/gimg/www.mia...3dc2e99443.jpg


I also captured some 0-60 data and 0-100 data on the dragy. It reported a 6.38s to 100mph and 2.98 0-60mph, it is 2.76 seconds 0-60 mph if factoring a 1 foot rollout as do all the magazine testers and manufacturers.

https://cimg6.ibsrv.net/gimg/www.mia...b8dec670dc.jpg
https://cimg0.ibsrv.net/gimg/www.mia...f59b9c73fa.jpg

Update;
I went to track again last weekend and made a few tnt passes. I backed up my previous best 6.91 second @ 105 mph 1/8th mile time with a 6.95. Time for more power and some weight loss after a few safety items are addressed. I purchased an Alston 8 point weld in roll bar kit but not going to install it until my hardtop i've ordered comes in so I can build to fit.

The hardtop I ordered was the cheapest aftermarket I could find. Here is the link to one I ordered. https://exoticeuroparts.com/shop/maz...termarket-new/.. I got the 10% off so after shipping it was $418.33. I also ordered this window and seal kit. https://treasurecoastmiata.com/i-158...treet-kit.html. I sure hope window fits.. I have the window kit in hand but still waiting on top. Anyone on here ever use this top?

Hi
I am new, I think this would be great on a supra jza80 to pre-spool the second turbo. It would require less air pressure as the second turbo has no load at this stage.
Has anyone tried this?

Hi little boy, are you lost?

Jk..

Hello Snuf,

Are you drag racing this car? Manual or auto tranny? I will tell you from experience my spool shot setup is best used for drag racing, or those occasional street pulls, and with an automatic transmission. This wouldn't be my first choice if on a manual transmission. There are a couple of reasons for that, which I can detail if you want, but for drag race with an automatic and a larger turbo this works very well. You may also want to give some thought to a small nitrous shot.

I doubt you will find anyone who has tried this on a sequential turbo setup. Very likely you will find very few who have successfully done this period.. You would most likely be on your own getting this to work on your setup. You may want to reach out to Pat for his thoughts as he has done a lot of work on compound turbos' and may have some ideas on implementing a spool shot system into a sequential turbo configuration.

-Marshall

Question: Anyone on here try a gt3576 or gtx3576?

I know thats a little on the large side for most on this forum, but for my setup and what I'm doing it may work well.
First, little background as to why Im asking. I have tried a number of different chinese turbos. I am currently running a chinese gtx3076 with .82 a/r exhaust housing. I have also ran that turbo with a .63 a/r housing. Trap speed in the 1/8th mile is about 2 to 3 mph faster with the .82 housing so thats what I kept on it. I have also tried a regular chinese gt3582 with a .63 ar on the street for a while and felt it made decent power, but was a little too lazy on the street when not using the spool shot. I wanted to put that turbo back on again to try it at the track, but we moved about 7 months ago and unfortunately that turbo was lost in the move somehow. My goal for this year is to try and trap 110 mph in the 1/8th. My best 1/8th mile trap speed so far with the chinese gtx3076 .82 housing is 106.82 mph, so I need to pick up about 3 mph. Seeing that the larger .82 ar housing is worth as much as 3 mph over the .63 a/r housing that leads me to believe the turbine was a little restrictive. I'm considering a chinese gtx3576 with .82 ar housing. That's basically the same compressor side as i'm running now combined with a turbine that will flow about 4 lbs pr minute more that my current setup. According to garretts' turbine flow charts the difference between the gt30 .82 ar and .63 ar is about 3 lbs pr minute, which netted me about 3 mph, so I'm thinking an additional potential flow of 4 lbs pr minute may help me reach my goal. I may also change my downpipe from 3" to 3 1/2" to help with laziness when driving on the street when not using the spool shot system. Any thoughts from someone with experience using these size turbos?

Update:

Just swapped china gtx3076 with china gtx3576. Both turbos have the exact same billet compressor wheel, however the gtx3576 has a larger turbine wheel. I'm using .82ar housings for both. The initial spool testing shows very similar spool characteristics for my setup. Unfortunately the roads here are a little too cold for actual performance data testing on the street with the dragy. However it should be quicker now with this turbo. It is exhibiting less internal exhaust manifold back-pressure, which should translate to more power. Hoping this change will get me to trap 110 mph in the 1/8th mile when at the track.

Hey Newaza is that you showing up on the Dragy leaderboard with this setup? I just got one and spotted some crazy guy with a spooled turbo setup.

What 1/4mile times do you predict you could achieve with the gtx3576? Asking for a friend.

I'm #3 on the leaderboard for mazda in the 1/8th mile with a 7.35. However thats an older time as I've gone quite a bit quicker since, but I replaced my phone and cant seem to upload later tests to the leaderboard with new phone. (btw, thats not my picture on there. Thats stock image from the dragy.. lol. Also not actually in mexico of course. I just dont want to attract any unwanted attention from the local popo.)

https://cimg2.ibsrv.net/gimg/www.mia...1765f92e3a.png

As far as 1/4 mile times go my best to date et of 6.91 in 1/8th equates to roughly 10.8 in1/4 mile and 106 mph in 1/8th is roughly 133 or so mph in 1/4 mile for power adder car. These previous best were achieved with china gtx3076. Traction has been limiting me a bit, even at the track. I'm going to be further addressing that part of the equation soon.
Im hoping with this new turbo and better traction to get in the 6.70 range at 110mph at some point this year. That should be good in 1/4 mile for high 10.40 to low 10.50 range at just under 140 mph. We see if this crap pile will hold together lol..

Which ebay vendor have you had luck getting these gt30 series china turbos from? It seems to vary from seller to seller

Well I had to create a new profile in order to save to leaderboard the runs I did with dragy after the new phone. The 6.92 run was done at the track. The timeslip showed a 6.91 while drage said 6.92, so only off a hundredth of a second so very accurate I would say.
https://cimg0.ibsrv.net/gimg/www.mia...e9af6c51f8.jpg
You will like using the dragy. Most difficult part is getting validated runs. You will get a lot of invalid runs for various reasons.

https://www.ebay.com/itm/GT35-GTX357...oAAOSw1~JZUKRC

This is the gtx3576 I just got and from this vendor. I also got the previous gtx3076 from them as well.
I have also gotten a couple other turbos from an ebay vendor called " usturbosystem". Altogether I have used 6 or 7 different ebay turbos to test and have been satisfied with them all. I did fail the thrust bearing in two turbos but Im pushing them hard so I can't complain.

Update: So I swapped out engine a couple weeks ago to have a fresh engine going forward. I keep 2 identical engines and swap every other year or so to freshen with new bearings, rings, gaskets or other parts as needed. I just pulled apart engine that was in the car. Everything looked really nice with the exception of the coating on the skirts. It was mostly flaking off. I called wiseco since this is supposed to be a permanent coating. They said coating peeling off can be an issue with high alcohol content fuel. Funny they don't mention that anywhere in there literature. Also its strange that I have used these in the other engine I rotate and coating did not flake off that set. That particular set looked prestine last time after cleaning and are on there second go around. Maybe this set used a different coating formulation or prep? Any ways I will just clean off the remainder of the coating and re-use these in anther block with proper ptw clearance without the coating. Just wanted you guys to know if your using e85 with coated wiseco's the coating will eventually flake off.
https://cimg7.ibsrv.net/gimg/www.mia...6c2e75e827.jpg

Update:
Since I am using a gt35 frame turbo now I decided to re-work my exhaust. I have swapped my front half from 3" to 3 1/2" and an open wastegate pipe. Back half is still 3", but I may change that as well. The drag strip is supposed to open again the 3rd weekend in april, but don't know if that will happen now with the covid virus situation so I may just have to test with the dragy to compare with previous data with the 3" piping.

I am also planning on changing the transmission fluid to a higher viscosity fluid such as John Deere Hy-gard or equivalent in order to hopefully tighten the converter stall just a bit. I will also likely make a minor change in the transmission valve body to increase torque converter pressure a bit to possibly help tighten stall and lockup clutch apply pressure. I will let yall know how these changes work just in case anyone else out there is tinkering with a jatco automatic in a miata.

Update; I decided to re-coat the skirts on the wiseco pistons that were pictured a couple posts up. The coating was successful as best I could tell so I reused them for my spare engine. I used techlines dfl-1 for the coating.
https://cimg1.ibsrv.net/gimg/www.mia...1be6db5800.jpg
https://cimg8.ibsrv.net/gimg/www.mia...d9d37cc2d5.jpg
https://cimg9.ibsrv.net/gimg/www.mia...0e96ae3ced.jpg


Also a quick update on the transmission. Since its been boring due to covid lockdowns I decided to pull and autopsy the tranny I've been running. Its still working, I just figure its time to pull and freshen since not a lot going on atm.

It is showing a fair amount of friction surface wear in the intermediate band, front clutch pack, and rear clutch pack. Those are the friction surfaces primarily used on my full power runs, The remaining fiction surfaces looked nice. I built a fresh transmission to replace this one and am building the one I took out to use for a spare. Although some of the frictions showed significant wear, i am very pleased with how this transmission has held up and performed. Its been together for a number of years and beat on regularly, so it owes me nothing. The mods for anyone looking to duplicate follow: I added 2 extra friction discs to the front clutch pack by removing the cushion plate and sanding pressure plate on tempered glass and checking with a micrometer while doing the sanding for flatness and thickness. I had to sand that pressure plate for proper clearance in that pack.The front clutch pack originally had 3 frictions now has 5. The front clutch pack is engaged for third gear.
The rear clutch pack I added 1 additional friction, for a total of 6 frictions. I did this by removing the cushion plate in that pack and replacing with one thicker steel for proper pack clearance. The rear pack is used on all forward gears. The remaining friction packs and bands are stock counts but also not overly stressed other than the intermediate band. The intermediate band is used for second gear. I would like to run a larger intermediate apply piston but they are very difficult to source so Im adding more apply force by adding line pressure, which adds more to all clutch packs as well.
The valve body was modded by shimming the pressure regulator approximately .250", all the accumulators were pinned for no movement as was the pressure modifier valve. All the orifice plug openings were enlarged substantially. The vacuum modulator pin was replaced with one about .150" longer (which I cut out of a nail LOL) and modulator is left unplugged since I manually shift using a linkage selector signal from the inhibitor switch to control the shift solenoids with no automatic function. There may have been another minor mod or two, but thats all I can think of at the moment and covers the major changes to successfully hold the power level I'm at currently. Hope this info can help if anyone else out there is looking to build and early model miata jatco to hold any power.

https://cimg6.ibsrv.net/gimg/www.mia...7b5dc0aa07.jpg

Time to get greedy for a little more power!

Will be adding this soon but I have to get a few more jets to test 35, 50 and 75 hp levels on top of whatever I have now. I'm really curious to see how a 50 shot spools the turbo compared to my compressed air injection system. Although the kit is rated up to 150hp i will likely limit to 50 and occasionally 75hp.

what a badass. I tip my hat to you.

My buddy netted 150 horsepower from a 50 shot on an rb26

Wow! That's impressive. I wonder if some of that additional power was due to increase in boost pressure from larger volume of exhaust gases? You would expect some additional power over what was rated due to additional charge cooling when used on power adder car, but 3x rated is insane.

I ran nitrous back in the late 80s through early 90s but only on small block and big block chevys as that is what I ran in those days, and never combined nitrous with another power adder so this will be a bit of an experiment for me. Thats also why Im starting with smaller additional hp levels but may eventually go up if car responds well and holds together.

I've seen intake temps drop over 100*F from the addition of nitrous to charged air. That does as lot for the engine's volumetric efficiency, way more than the nozzles "shot" size rating. On one of my fathers old big block Mopars, he ran nitrous in place of any intercooling for packaging reasons and because it was so efficient in the short bursts that car ran in.

On the RB26 it was a spool assist device and tapered off as the engine reached full boost. The 100whp difference was at the same RPM during spool up and not peak, for clarity. It was a 800awhp car.

Nitrous to boost is akin to adding baking soda to cocaine.
Always has a bigger gain than what you expect.
One big problem with funny gas is that in a single stage system the same amount of nitrous is injected regardless of engine speed or load.
It's way too much at 3000 rpm and not really enough at 6000.
It tapers off by itself...
This can happen at idle which is catastrophic.
The drop in temperature can freeze the solenoids open. This is BAD.
Progressive systems exist, they are far more expensive and require specialized tuning skills.

The cooling factor is HUGE, especially on a car that has increased intake temps.

Nitrous will end up being a more powerful solution for "spooling the turbo faster" but it is not nearly as ingenious as Newaza's original use of an AC compressor.

My father, who is also a car nut, has a XKE that at one time had triple turbos, ITBs, 12 staged injectors, and individual port nitrous injection (both NO2 and fuel) on a 6 cylinder.
Far more complicated than it was worth.
It was a tuning nightmare...
It ended up with a single turbo flowing through a stock fuel injection manifold with 6 normal injectors.
Made less power but it was still enough to decimate the skinny ass rear tires at any speed.

Got the kit installed and tested with 35hp jetting. Didnt have a chance to wring it out as too many people around spot where I test. I did get a couple short hits from about 25mph to get some "seat of the pants" data.. My compressed air system definately spools the turbo harder than just a 35 shot alone, but used in conjunction its pretty gnarly. Although I also took out a fair amount of timing for first test at such a low hp level, it feels like it pulls harder in boost as well. I will be testing a 50 shot next but jetting will be one size rich on fueling as thats what I have on hand. I was hoping to trap 110mph or better in the 1/8th when track opens back up. Judging from initial feel with just a 35hp shot I think a 50 shot will easilly get that goal accomplished if everything holds together and works right.

I did a little testing with the 50 hp jetting today. This level spools roughly equal to my compressed air spool system. Using them together and it spools VERY fast, and running it out car pulls noticeably harder. The nitto drag radials dont have a chance LOL... Will leave it at this jetting level for a while I think.

One observation in case any one else on here wants to try nitrous with a turbo. You will need to lower your boost level before spraying if you want to have the same boost level with nitrous as you had without. . The nitrous will add a couple lbs boost as well.

Hoping track gets up and running soon so I can get some solid data with halfway decent traction. Should be able to improve on numbers posted in my signature quite a bit. Those times were done last year with a gtx3076 .82ar churbo and no nitrous. I'm now rocking a gtx3576 .82ar churbo at same boost level and 50 shot nitrous. Car is most definitely faster up top, but elapsed time was traction limited before. So traction will be even more of an issue now, but once tires hook it goes! Traction and maybe having a slightly tighter torque converter built will be next on the agenda.

Well I finally went out taking the dragy along and got a small amount of performance data using a 50 shot to compare with no nitrous. I use 50-70 mph range to test modifications that are for power as I can usually get decent traction by 50mph with the drag radials and 70mph is not so fast where if the popo sees me he may not take me to jail lol.. Also I can just use 2nd gear. My previous best was 1.05 seconds 50-70mph, and that was at the track. I just got a .89 of a second 50-70mph run on the street, so its definitely making a difference. Cant wait for the track to open and get some solid data on this junk! Will likely test first time at track using 35hp jets as I have yet to test while loaded in third gear.

Update: Found the limit of the stock torque converter. I quess the friction material on the lockup clutch in the converter didnt like testing with a gtx3576 churbo at 35lbs boost combined with a 50 shot of nitrous Lol... The fiction material on the lockup clutch disintegrated. I had to disassemble the valve body to clean out the friction debris as well as flush lines and cooler. Back together and working, but with no lockup.

I contacted Florida torque converter and they will build me one with heavy duty sprags, bearings and frictions for 399 plus 100 refundable core and tax. That is very reasonable so Im going with it. I was previously considering going a little tighter on the stall speed anyways so this works out.

Just had these guys build me a better torque converter. I sent them a core to build and they had it done within a couple days after receiving the core. Super fast service and they will work with you on needed mods and strengthening. I will get this installed and tested soon and will report back any improvements.
https://cimg4.ibsrv.net/gimg/www.mia...1bc7dcfd14.jpg

That's something I didn't think I'd ever hear on this forum. :D

Been watching this project with some interest. Drag racing doesn't really tickle my pickle, but innovation is cool, even if it's being used for drag racing.

Well snap! I swapped in fresh built converter yesterday and tested it. It was too tight. I need to send it back to get it loosened a bit to raise stall speed. My fault I quess since I did ask them to tighten it up a bit to lower stall speed a tad. I quess I didnt specify what I meant by a tad. lol.. No biggie though, however I am down to my last good stock converter. I put it in and tested today and all is as it should be for now. Not sure how long this converter will last if I spray a 50 shot nitrous and 35+ psi out of a gtx3576 churbo. I will just use this one until I feel like changing back to the built converter after I get it back. I had 3 good stock converters, down to one!

Update:
My most local track finally opened last weekend(Savannah river dragway). Fist time all year. They did some resurfacing so traction atm is really not much better than on the street. It will get better as more cars with slicks lay down more rubber.
I made some test passes with new turbo setup. Last year I used a gtx3076 with an .82 ar turbine churbo and ran a best of 6.91s et and 106 mph in the 1/8th. Currently I'm testing a gtx3576 .82 ar churbo, after about 6 passes over the two weekends i got a 7.04 @ 106mph with a couple pounds less boost than running last year. Traction was not good due to fresh track surface and my cheap nitto drag radials which may be going away. This turbo setup will definitely get me back into the 6s 1/8th mile, but will require much more careful feathering of the throttle than turbo used last year to do so. If I let off throttle too much to try and regain traction the boost falls off and is very lazy to recover without my spool shot, and unfortunately it takes a lot of air to spool this turbo so most of the stored air is used at the launch. So when I have to feather the throttle for traction its a real challenge to balance traction without losing too much boost. The gtx 3076 .82 recovered very fast once it got going and was much easier to modulate. I have a .63 ar housing I'm going to try for the 3576. Hopefully that will make this turbo behave more like the one I used last year. Looking at the turbine flow maps for the gt30 .82 ar housings vs the gt35 .63 ar housing they appear to have similar mass flow rates with the gt35 .63 having a slight advantage at higher pressure ratios. Was hoping to use the gt35 .82 ar since it has a significant flow advantage, but I think my stock head and cams just cant take advantage of it.
Haven't tried the nitrous at the track yet. I figured I was struggling for traction as it was, no need to make it worse.

Just ordered 2 of these. https://www.summitracing.com/parts/hoo-17325dr2

Will be testing soon. Hopefully these will give me enough traction to finally test a 35hp shot of nitrous (which likely adds more like 45hp on a turbo car) at the track, which I have yet to do. Looking for high 6.80s and 106-107 mph in the 1/8th without nitrous and maybe 6.70s at 110 with a 35 shot.

Got the hoosiers drag radials installed.
https://cimg7.ibsrv.net/gimg/www.mia...87b2bddc03.jpg

I also added another 3 gallon storage capacity to my spool shot system.

Took to the track tonight and after a few tries ran the time below. This was still no nitrous and was running the gtx3076 churbo tonight. I need to learn these tires and figure best tire pressure to run, also need to practice best launch technique with the extra air capacity. I think it may go high 6.70s @ 108mph without nitrous but with more practice on new tires and maybe some cooler air. Im thinking now a 50 shot of nitrous may get me in the 6.60s @ over 110!
https://cimg3.ibsrv.net/gimg/www.mia...e9ee649577.jpg

Someone sent me a video of one of my passes last night. It was not a good run as the car fell on its face for some reason when I shifted from 2nd to 3rd and only ran a 7.11 at 100mph on this run. However since I really dont have any other decent video on the car running I made it into a youtube video to post here.

I just installed a cheap proform 67005c shift light. I suppose the rpm adjustment dial on the back is just a suggestion LOL... Its only off about 400-500 rpm. Oh well, it was only 25 bucks so I can't complain. It does seem to work once you set the rpm correctly, and by correctly I mean off the tach, not the dial on the back of the light. I haven't tested it enough to see how repeatable it is. Hopefully it is so its not just decoration.

Well crap! I went to the track tonight and broke another converter. The one in the car now thats broken is one I got from florida torque converter. I bought another one from them but this time with stock stall speed, however its built with supposedly heavier duty parts and brazed fins. Its supposed to have a year warranty so we will see what they say. I'm a little bummed about this one giving up as I still havent shot nitrous at the track or really reached the power level I plan on eventually reaching. This supposedly heavy duty converter giving up at the current power level was not expected. Im going to have to rethink how far I want to take this hoopty or redo the driveline with stuff to hold bigger power eventually.

Update:
Sent converter to florida torque converter. They opened it up and said it looked ok inside other than a little bluing on the apply surface for the lock up clutch. Got a fresh converter back. I dug into the transmission and found the intermediate band was broken. So I repaired the transmission with a new band and seals for the intermediate apply piston. I took a little line pressure out to help relieve some of the stress on the band as well. Car is back together and tested. Hope to have at the track this Saturday weather permitting. Looks like Im starting to see the limit for some of the hard parts in this transmission and converter. I quess I cant complain. These old jatco transmissions have exceeded my original expectations. According to the wallace race calculator my 1/8th mile trap speed of 107.86mph and wieght with driver of approximately 2600lbs puts me at about 507hp at flywheel. 1/8th Mile ET-MPH-HP Calculator So the jatco has done well all things considered. However I think I will move on to a built c4 or powerglide at some point next year. I actually intended to do the c4 swap before even trying the jatco. Actually built a c4 to have ready, but I sold it after trying the jatco and having it live. Wish I had it back now lol... Really want to start throwing some nitrous at this thing but the current driveline just will not hold any more so will have to wait until I swap tranny and rear next year.
https://cimg3.ibsrv.net/gimg/www.mia...6fd436acbe.jpg
https://cimg6.ibsrv.net/gimg/www.mia...fbeafd96fa.jpg