Nice work. I am using this manifold and initially considered porting it. So very interested in hearing your take on the results.
I see these manifolds are back down in price, $74 for the T3 version. IIRC at one point they were $120 or so.

BTW, I saw this video recently, on using the data from Draggy to load virtual dyno. Thought it might interest you.

Thanks. I haven't done any more follow up testing to get solid data on any performance improvement. My initial impressions were positive. I did add a divider in addition to some opening it up. The dragstrip will be back open early march so should know for sure then. I have a couple more mods to the manifold I may try as well. Its cheap junk so I have no reservations about cutting or welding on it.

The dragy to virtual dyno is very interesting, Thanks for linking that.

I doubt that I will personally bother with doing all that for a couple reasons. First i'm not sure how accurate it will be with my setup due to there being not necessarily any direct correlation between engine speed and wheel speed when accelerating hard from a very low speed when in say third gear for example. The converter is very torque dependent in so far how high it will stall. Lets say in a scenario where Im accelerating full throttle from 25 mph in third gear and am using the spool shot system. If using the spool shot I could very well be at full boost (35 psi for example) before 40 mph and the engine speed would very likely be at or near 6000 rpm even at that low wheel speed due to converter slippage. The engine speed would just basically hang at roughly that rpm while the car is accelerating. Once the turbine speed in the converter gets closer to the impeller speed the percentage of slip starts to reduce and the engine speed starts to increase as the turbine and impeller get closer to being more coupled. In other words in a real world test for me going full throttle from 25-110 mph and in third gear the whole time The rpm might hang out going from 6000rpm at 40 mph to maybe just 6200 at 80 and only after 80ish to 110ish engine speed going from 6300 to 7300 lets say. Im not sure how accurate such a graph on vitual dyno would be in that scenario.
Secondly in my mind trap speed is king insofar as measuring hp vs weight, more importantly how efficiently one is using whatever hp they have available.
For me personally trap speed data when at the track and time to speed data from the dragy when street testing give me a good indication of power vs weight changes. The E.T. and 60' data from the track tells me how quickly im able to start applying whatever power I have available.

More ebay manifold butchery!!
Those last couple mods on the ebay manifold seemed to net a slight improvement. Had to richen mixture so it likely flowed better. So I figured what the heck. Lets pull this junk manifold back off and look for more improvement. If I ruin it no biggie. I opened up the top portion of the runners leading to 1 and 4 and grafted on some tubing going to the top portion of the plenum. Intuitively it seems as though this should further improve. I just need to test to verify and get some solid performance data. I once again had to richen a bit, so it likely helped as well Look beyond the crudeness... thats the way I roll on this junk LOL....

If these last round of changes to the manifold show an improvement and the casting holds up after the hackery Ill likely just keep this manifold on the car. I may eventually pull it back off to spend a little time blending and smoothing inside for flow, but that would be about it.

https://cimg2.ibsrv.net/gimg/www.mia...c210208fe1.jpg

https://cimg6.ibsrv.net/gimg/www.mia...fe380f4117.jpg

https://cimg2.ibsrv.net/gimg/www.mia...89ccc29685.jpg

Making some more changes to hopefully save weight and further improve performance of car.
I will be testing a pretty novel idea for building boost on the tbrake without using the spool shot system. I was using two steel air tanks totaling about 9-10 gallons capacity. I swapped those for a 7 gallon aluminum tank to save weight. However less capacity means I would rather not use spool shot to build boost on the tbrake. Saving the spool shot for actual launch. Im testing out some other ideas to build significant boost at a relatively low rpm when on the tbake.

On the manifold.
So did you block the runners from where 1 and 4 normally hit the flow from 2 and 3 and force them into the new section you added?
If so, then I would expect that to make a real difference.
Can you quantify what improvements were made on each modification a little further?

On the first go around I added a shaped barrier in the bottom portion of the middle of the manifold between 2 and 3. You can kind of see it in the pics although the pics arent the best. When I did the top runners I also added a bit of a short, curved "lip" on the exits on one side of the ports of 2 and 3 to try and discourage dilution between 1 and 2 as well as 3 and 4, but cant see in the pics.

For the merged top runners i opened up and removed top sections of the manifold to "siamese" the new runner additions if that makes sense. It likely does flow more at this point since I've had to add a good bit of fuel to get mixture as it was before I started modifying it. However I dont have enough solid dragy data to quantify any exact performance improvement yet. My initial impressions are if I pull it off once more to do more interior runner clean up and shaping is that it will be good enough for me not to bother swapping to a header. Everything is already built around this so even if its not quit as good as a long runner header it will be good enough for me. If/when I pull it back off to clean up I will try and take better pics. I am going to build a 3 1/2" downpipe to run at the track in the future I think. Would be nice to get rid of that full exhaust system weight plus multiple other benefits to doing larger open downpipe at the track. My exhaust is all v band so not hard to remove for the track.

Just came across this. I believe he is still on a mazda bp based engine. 8.09 in the 1/4 mile. As Jesse lee Peterson would say, AMAZING!!!!

Hello fellows another quick update.
So I've been doing dragy testing in the 40-80mph range that i normally do when testing mods and unfortunately the gains from the manifold mods are too small to be consistently measured in that short speed range in terms of acceleration improvements. Bummer! I was hoping for more. It may show some slight gains in the 1/8th mile since its a much longer speed and time frame. The only thing I can say for certain is it required a little more fuel up top to get afr to match prior, which should mean a little more power.
I also just changed crank wheel to 36-1 and ground off the two close teeth on the cam wheel for sequential with speeduino. I was running sequential with the stock 99-05 trigger but had some spark latency. I made up for the latency in other ways but didnt like doing that and wanted to get rid of the latency. It appears that the new wheel setup timing is rock solid with no perceptible spark lag so I no longer have to trick any spark maps or other ways to make up the latency as I did prior. Unfortunately speeduino doesn't yet have a place for latency compensation as does megasquirt. I really want to start doing some nitrous testing this year to see how it compares at the track to spool shot for spooling turbo at launch and really wanted a little more stable timing with no tricks to be on the safe side. If i do start testing nitrous at launch and can get similar results to spool shot I may eventually remove the spool shot setup. The spool shot setup has been a big winner on this car and is a MAJOR contributor to its overall performance, and is great on the street since the "shots" are free, but the baggage is weight unfortunately. After watching Pat I'm starting to eyeball some weight reduction a little more seriously.

I hope the nitrous will get you off the compressed air and you do start shedding some weight. I bet your car would be in the low 6's in short order.

OOps!!! Got a little greedy at my test spot. Good thing I had walking shoes on LOL....Broken input shaft.

https://cimg3.ibsrv.net/gimg/www.mia...97ff8fab6a.jpg

Just picked up a core c4 transmission to build up. I guess y'all can see where this is going LOL...

I wont build it to the level of Pats transmission though. I'll likely build it to hold a comfortable 600hp or so level at my weight. I will also likely pick up another c4 to build up in anticipation of a higher level down the road. Hard parts are available for these things to hold some pretty serious hp levels (for a miata anyways). The c4 has some other advantages over the jatco as well. For one it is quite a bit lighter, secondarily it consumes less power, both of those should help performance to some degree.

https://cimg8.ibsrv.net/gimg/www.mia...1101762753.jpg

I did put my spare transmission back in the car for the time being. I also went ahead and repaired the one with the broken input shaft, so its ready to go as well.

The ford transmission should be ready to go in a couple months. I'm not sure if I will go ahead and convert the tranny over then or just wait until the end of the year and do the rear then as well. I'm actually kind of looking forward to doing the c4 now. That was actually my original plan years ago before I went with the Jatco. Oh well, at least the jatco was nice on the street due to the 4th gear.

That's cool. Will you build it yourself or have a shop do it?
What will you do for an adapter plate?

Build it myself of course. These older transmissions are actually quite easy to do. Dealing with all the bushings is the only real pain. Besides, I'm waaayyy too cheap to pay someone LOL..

Dont need an adapter plate. The jatco bellhousing only takes a little modification to bolt on in place of the ford bh, Thats why I went with a c4. I would prefer a powerglide since i have used them in the past and its among the lightest, lowest power loss automatic out there suitable for drag racing in a light car, but it would be more of a challenge to adapt.
the c4 tranny does require a custom converter, driveshaft, mounts, shifter, yada-yada,,,,all thats really no biggie. The custom torque converter can get a little pricy, but on my first go around I think I have a cheap solution i may try for that too.

Quick update. Bellhousing is finished. Pic below is it sitting on the ford c4 pump with bolt going through new holes for correct orientation. I epoxied in a centering ring cut from a thin strip of what i think is 21 gauge steel. This finished product is a very snug fit.

https://cimg1.ibsrv.net/gimg/www.mia...f4329080e7.jpg

Next step is to build the transmission.
I pulled the transmission apart to see condition and what parts were needed. Also to try and determine why it was originally taken out of service since this was bought as needing rebuild. The tranny looked really good internally except the forward drum clutch pack shows significant wear. Upon disassembly of the forward drum I found the cause. The belleville spring was broken. pic below shows damage.
https://cimg9.ibsrv.net/gimg/www.mia...8183678a50.jpg
https://cimg0.ibsrv.net/gimg/www.mia...d43602ba4f.jpg

The track opened back up yesterday as well for the first time this year. I decided to take the car up there to play a bit. I made 3 passes. Since the car has been breaking so much drive line stuff as of late I decided to take out a few pounds of boost and launch with very low rpm and very low boost. Naturally the car was not going to be very fast but I just wanted to go play a bit. My first two passes were against a acura with a turbo k24 that the owner said dynoed over 600hp. Since he was front wheel drive and on drag radials, not slicks, he wasnt really competitive. I beat him by a lot both times. Unfortunately my third pass was lined up with a well set up smallblock powered s10 pickup on big slicks, so I lost my self control on the original plan to launch at low rpm and no to low boost. Once I realized I was going to run him I enabled the spool shot system which on this particular tune in the ecu was already mapped to try and launch at around 15-17psi and about 3800 rpm. Well it launched at around that and proceeded to break something in the rear suspension. I havent been under the car yet but I suspect it cracked the subframe somewhere near one of the lower control arm mounts. I was getting rear steering. Oh well, no biggie. All this just gives me more incentive to hurry up and finish the driveline with strong stuff so I can throw some real power at this hooptie. Im hoping that after I do the tranny and rear to be able to start throwing some nitrous at this thing to eventually possibly dip into the high 5s in the 1/8th.
On a positive note I did get a dragy video of my first pass. I have never done a dragy video so thought this was pretty cool and should share. This was my first pass against the honda. You cant see him due to phone camera angle, but you can hear him right before the launch rev up and go on two step. You never hear him after that because he just basically spun and fell way back. Again keep in mind this is low boost (for me anyways) and now real rpm or boost at launch, so this pass is naturally going to be slower than usual. Now that I know how to do dragy overlay videos y'all can expect some more in the future, but with much quicker times. This pass was only a 7.05. the car has run in the 6.50s, but breaks driveline stuff half the time trying to get there or go faster. Fixes happening soon!!

The dragy video can be trimmed so that not so much after the finish line is played and you can change what increments are measured ie the 1000ft and 1/4 mile don't have to be displayed.
I look forward to more dragy video.

Quick update and maybe even a laugh...

Transmission is done. Replaced all broken parts and built with red clutches and adding an extra clutch in the direct drum by using thinner steels and sanding pressure plate for clearance. I replaced the intermediate servo with a "h" servo. That gives holding surface area very close to the "c" servo most aftermarket units are based on. It is also converted to full manual, no automatic function.
Next step will be figuring out a converter solution. I have a couple ideas that I will be exploring soon in that regard, but if they don't pan out I guess i'll have to break down and spend the money on a custom converter.
https://cimg0.ibsrv.net/gimg/www.mia...979c025e75.jpg



Tanks and compressor taken out for now, maybe permanent, maybe not. There is about 40ish pounds difference between what I removed so far and a full nitrous bottle.

https://cimg6.ibsrv.net/gimg/www.mia...8074eae5e6.jpg


I removed most of the spool shot stuff so I can start testing the nitrous for rapid spool at launch when at the track. I have street tested a 50 shot against the spool shot system to compare boost rise over time. The spool shot does spool the turbo faster than a 50 shot so I now have slightly larger jets, likely equivalent to maybe a 60 shot to test. I may go a little larger later. Since the tanks and compressor aren't in the car I will be forced to use the nitrous now to spool turbo. Its really about time to start using it and gathering test data for spool at the track. I have it configured to fire at launch when brake is released and shut off when 250kpa is reached, so will just be using at launch to spool turbo for now. Once all the driveline stuff is eventually done I will start to stage the nitrous to add power down track as well as launch. Junk should be pretty quick at that point.


Anyhoooo The track was open for tnt last friday so I wanted to get to the track for a couple reasons. One, to test the 60 shot for boost rise at launch. Secondly to get yall some better numbers on the dragy overlay video now that I know how to do it. Last time I was too much of a sissy chicken boy and was too conservative at launch for trying to preserve driveline parts. On the 7.05 pass it looks like I left at only 3300 or so rpm and a pip squeak 4-5 psi. I was going to get a little more gnarly for y'all and go ahead and try to bust out a 6.50 something in the 1/8th and maybe a mid 2 something for 0-60 and get it on the dragy overlay. I know about what boost and rpm level I need to launch at to achieve those numbers now and was going to go for it for yall. 50-50 Yall would have gotten to see me break something and coast down the track though lol....
Well last friday I loaded up the car and left for the track. About 2 or 3 blocks away I realized I forgot to throw the spare trailer tire in the back of the truck, but I figured, be a man and press on, so being the manly man that I am, I pressed on..... The track is about an hour from my house. I picked up a buddy who lives at about the halfway point to go with. Below is about 5 minutes from his house after picking him up..LOL
https://cimg6.ibsrv.net/gimg/www.mia...8488e37294.jpg
Needless to say didnt make it to the track. I just limped back to buddies house and left trailer there. Went back saturday to change tire and bring trailer back home. Got 4 tires coming and going to build an attachment on the trailer to hold spare so this doesnt happen again.

Sucks about the flat, better luck next time!

Update time
Finally got the converter solution done... I think LOL...
I bought an 8" c4 converter from a fellow racer. The converter flashed to about 5000 rpm for him behind a 347 smallblock ford. It was in a maverick that ran in the 6.20s at around 108mph.
I had to cut off the ford mounting pads and figure out how to adapt it to mount a c4 transmission to a mazda engine using the mazda bellhousing. The tranny and bellhousing I did prior.

I mocked up a mazda block and crank to the ford c4 pump and modified bellhousing to get measurements and figure out the easiest solution for me. Below is a pic of my mockup setup
https://cimg8.ibsrv.net/gimg/www.mia...9e649d994a.jpg

I came up with a plan to do a simple pilot bushing adapter to have machined in steel to weld onto and over original ford pilot. In the meantime I was talking to a friend who just happened to have an old lathe he inherited from his Dad that was just taking up storage space and he wanted it gone. I picked it up for $200 and replaced the motor with a 1hp harbor freight unit as well as getting new drive belts. The lathe is an ancient southe bend 8 jr, but all the critical stuff is still in good condition. They used to build stuff to last back in those days for sure!

I had a friend 3d print what I thought would work for a pilot adapter. After test fitting the plastic model and seeing it would work I chucked some steel stock in my new toy and started spinning away.
https://cimg2.ibsrv.net/gimg/www.mia...0f928f188a.jpg
https://cimg6.ibsrv.net/gimg/www.mia...68bcd954e0.jpg

After tack welding over the original ford pilot I had to come up with some ways to try and determine if pilot was true after welding. Although I got a large 4 jaw chuck the came with the lathe the converter body would not quite clear the ways. So I just mounted on some v blocks and checked in that manner as well as putting it in mock up set up. While testing on the v blocks I was getting about .003 indicated runout, which I feel is acceptable. More on this in a bit.

https://cimg1.ibsrv.net/gimg/www.mia...dfe0fd394f.jpg
https://cimg6.ibsrv.net/gimg/www.mia...35e9faed8f.jpg

next I had to build some mounting pads to bolt to the flex plate. I went with 3 as the converter had 3 "bosses" originally in the body so it was easier to do with 3. If 3 mounting pads is good enough for 1000+hp chevy's its good enough for me.
I built 3 pads with the proper spacing to mount in 3 of the 6 holes in a 99 model flex plate. After welding those up and the pilot as well I mocked up to measure the runout of the face of the mounting pads. I got .004 so pretty good on that too.
Below is a pic of mock up pad measurements.
https://cimg8.ibsrv.net/gimg/www.mia...164cdb4fe7.jpg

After all that was done I bolted just to the flexplate to measure runout at the pump hub. When I initially bolted it together I was getting runout of 8-9 thou, after it was bolted together a while it seemed to reduce to around 6-7 thou. Thats evidently pretty good too. Out of curiosity i mocked up a stock miata converter to measure pump hub runout. It was almost 15 thou, so I must be golden on that. The factory flexplates have about 25 to 30 thou face runout before a converter is bolted up, I measured 2 of them. So the flexplate runout will influence the pump hub runout until the pump hub is supported by the hub bushing in the pump.
Below is a pic measuring pump runout.

https://cimg5.ibsrv.net/gimg/www.mia...2a98e3eca0.jpg

At this point I am calling the converter and transmission done. My only concern, and its only a slight concern, is the converter balance. When I built the mounting pads I adjusted the weights to each other within a couple grams. The unknown is the welds weight. the welds are all equally ugly so hopefully they all weigh roughly the same, or at least close enough.

For now the converter and tranny assembly will be just sitting pretty for a while.

https://cimg9.ibsrv.net/gimg/www.mia...7402b31014.jpg


Next will be getting the shifter, rear tranny mount and driveshaft done. Hopefully all that is completed in the next few months. I plan to build or collect all the parts and swap over at one time so I can keep car to continue to drive and race as is until then.

Got to decide what I want to do about the rear setup before doing driveshaft though. One good thing about having the lathe now is I was able to redo the adapters for the 929 axles, I think they may work now, so I am leaning to keeping rear and adapting the 929 axles, at least for a while anyways. Since I have the axles I may as well.

Well my OCD kicked in and I did a thing LOL..... Spoke with Pat and he mentioned that FTI likes no more than .001" runout on the converter pilot. I initially felt that the pilot I had welded on to the front of converter was good, and it very likely was based off of runout measurement on the pump side of converter. However after thinking about it further I really didn't like the v block way I measured the pilot after welding as It did not really directly measure runout at very end of pilot. Sooooo,, I cut the weld and removed the pilot adapter I welded onto the front of the converter and devised a way to build an adapter to register off original pilot on the converter and bolt to back of crank to register into crankshaft side. Doing this way I can directly measure runout at very end of pilot adapter.

Below are pics of the new adapter I built. I was able to achieve less than .001 runout this way directly measured.

https://cimg8.ibsrv.net/gimg/www.mia...169dd93669.jpg
https://cimg2.ibsrv.net/gimg/www.mia...3824fb524b.jpg
https://cimg4.ibsrv.net/gimg/www.mia...691488ea72.jpg
https://cimg6.ibsrv.net/gimg/www.mia...18d1ca815b.jpg


However there are two issue with this one that I do not like. One is I had to make it out of 2 pieces since I didn't have any stock big enough to make it out of one piece. Secondly the wall thickness I feel is too thin on the converter side. If the bolts ever loosen or if the flexplate ever cracks, which I've had happen before on a nitrous sbc,The pilot needs to be sturdy enough to hold converter in place. I made the o.d. of that side that size so I could fit in a socket for the flexplate to crank bolts, but I feel now too thin. So I ordered some steel stock large enough to make out of 1 piece and will be full height thickness on the converter side. I'll just use longer bolts to mount onto crank. This should be last iteration as I know it will be true and extremely strong to hold in center should flexplate ever fail

After making the converter pilot adapter in above post I decided to redo it in a much stronger fashion. The new design is machined out of one solid piece of 12l14 steel. This one is plenty strong to hold the converter pilot centered if the flexplate ever breaks. After bolting it up to my mock up block I was able to get around a thousandth runout measuring at the register for the converter pilot. I am pleased with this one and finally calling it done and moving on to next part.

https://cimg5.ibsrv.net/gimg/www.mia...a2e483f334.jpg
https://cimg8.ibsrv.net/gimg/www.mia...4566559f4d.jpg
https://cimg5.ibsrv.net/gimg/www.mia...71d1cc6378.jpg

My one and only concern with this adapter is I had to source some 40mm long 12mmx1.0 flywheel bolts to work with the adapter. These bolts are for a honda!!! I cant believe I'm reduced to honda parts. Whenever I get all these parts collected/built and swap over to c4 tranny I'm only hoping I don't wake up the next morning and all the sudden my junk is 20 decibels louder and somehow sprouts some goofy looking giant wing off the back LOL.......

Lol you cracked me up with that!
Bwaaaaaaaaahhhhhh