Anyone out there running a GT3076R?
 

Just as the title says... I'm looking to see where you are hitting your peak torque RPM-wise. I have a turbo eerily similar and am plotting some calculations on the compressor map based on the GT3076R. However, with the calculations I have now based on 20% total airflow, I am AWFUL close to the surge line. If I knew the peak torque reading I could be calculate these things. Thanks in advance for the information and advice guys and gals! Boost will be at 17-20 psi BTW...

Below is what I have thus far (based on 20% of max airflow @ 8000RPM redline, 1.9L engine) CLICK THUMBNAIL:
http://thumb9.webshots.net/t/62/662/...9ljupoh_th.jpg

3076 on a 1.6L:

http://boostedmiata.com/dynos/3076_dyno.jpg

Thanks Braineack... I had actually come across that by searching but it looked like there were no BP-ZE's running this turbocharger at all. Should be interesting to see if one turns up out of the blue.

compressor wise, is it the same as the 2876?

I'm using that turbo and the car should be running by the end of the day. It's going on the dyno this Saturday, but I'll just be running a base tune and a 1 bar spring in the wastegate. In the next week or two I'm having it tuned and will up the boost until I run out of injector.

I think it is more similar to the GT30R housing, but don't quote me on that. I'm pretty sure it has a T04S compressor housing.

The specs on the turbo are:
Incon Systems GTBB37
Compressor --- Ind. X Exd. 55 mm X 76 mm 52 trim A/R .60
Turbine --- Exd. X Ind. 53.5 mm X 56.5 mm 90 trim A/R .86

Keep me updated on this as I see you are running the 1.9L as I plan to do. I still have awhile yet until I'm running so it would be good to have a comparison. Can't wait to the see the results, pics, and video (hint, hint). :D

And yes... :useless:

Click to enlarge:
http://thumb9.webshots.net/t/62/662/...9PjGbey_th.jpg
http://thumb9.webshots.net/t/73/173/...9swkVNB_th.jpg
http://thumb9.webshots.net/t/75/75/0...9wODZQq_th.jpg
http://thumb9.webshots.net/t/66/766/...9fJhrTJ_th.jpg
http://thumb9.webshots.net/t/62/662/...9RwOeyi_th.jpg
http://thumb9.webshots.net/t/66/766/...9prnSYk_th.jpg
http://thumb9.webshots.net/t/75/75/0...9VrQdxq_th.jpg

I just hope that is a 7 psi run or something because that is a damn narrow power band for little over 200bhp.

No, yours is a td04 wheel or something like, the 3076 wheel is a different size/shape/style.

user was cptnsloni, pretty sure it was 12psi. it helps if your turbo spools before 4K.

garrett put a mitsu wheel on my shizz?

it's a TO4S style also. just smaller inducer.

What's the size of the 2876 y8s? I have seen dynos of my exact turbo on a few SR20's and it has made anywhere from 350-420WHP depending on supporting mods and boost.

Turbo 705330-2
CHRA 446179-18

Compressor
Ind 52.7mm
Exd 76.0mm
Trim 48
A/R 0.70

Turbine
Wh Dia 53.8mm
Trim 76
A/R .86 or .64 (i run the 64)
Type Internally Wastegated

though mine has a welded flapper and I run EWG.

http://www.turbobygarrett.com/turbob...0_2_comp_e.gif

just looking, it appears to be a better suited compressor based on your lines above. it puts you a little bit further away from teh surge line.

Yeah... I actually have that plotted I do believe. I'll have to post it when I get back to work on Monday however. The GT2876R WAS a better match for the engine, but wouldn't get me to the power capability that I wanted and also, I got a steal on the INCON GTBB37 turbocharger... I too have the internal flapper welded shut and plan to run EWG as well. :D

On a side note: My plots assume that you are making full boost at 20% of airflow, which as you all know is not the case at all. Peak torque should be a much better estimate as you know you are making full boost at that point and maybe tach off another 1000 RPM to from the peak torque RPM to assume that you are at full boost by then...

JayL! I needz dyno data! :D

I'm seeing full boost at 3750 but then I only run <10 psi.

on mine i'd call 15 psi at 4250 and 20 psi at 4750 give or take a hundred rpm.

max boost at 20% airflow sounds fun.

Haha! Yes, max boost at 20% of max airflow does sound fun... Thus why it's only an assumption unless I run a GT10 series. :D

Here it is. Unfortunately it's pretty much worthless and not a good representation of what this turbo is capable of. You could say that I have lots of work to do.

Haha! Appreciate the dyno Jay. I'm guessing this was at 10 psi as you mentioned earlier? Do you have any datalogs of boost levels and how they climb with this turbocharge on the 1.9L? Thanks again man!

Ask and you shall receive, this is the only one that has manifold pressure on it. Just remember that something's not quite right with the car. If you have any ideas what it may be by looking at these runs, let me know.

Thanks very much Jason! That is odd how it is breaking up and drops off at 5750-6000 RPM. Maybe in your timing map or your plugs? Just strange that the power doesn't match the plot of manifold pressure at all. As it seems you are boost creeping up to ~17 psi by redline, but not making any additional power past 5750... Odd. It does look like there is a lot more power potential that could be had from this turbocharger setup. :D

ps - What RPM do you have your VVT kicking in?

5500 is when it makes the switch. I wish I would have thought to unplug the solenoid to see if that was the cause of the problems. I started a thread in the dyno section about this, hopefully I can get it sorted. When I do and go back to the dyno, I will post the dyno plots in this thread. This turbo is capable of so much more.

Thanks! Yeah, it would have been nice to see if the VVT was causing this or not... I have also checked out your dyno section thread. Hopefully it gets sorted for you soon. Good luck!

Based on the RPM vs Pressure plot that Jason provided I was able to make my compressor plot of the GT3076R more accurate and get out of surge territory. I assumed that the turbocharger would be at the full 20 psi by 4300 RPM. Made the plot look much nicer and fit within the surge limit nicely. Thanks for your help with this Jason! It is MUCH appreciated.

Also, in looking at my Source Data for the plot on Excel I was had assumed a 3200 RPM spoolup since this Excel document was originally designed for a GT28 on an SR20DET. Yeah, 4300 makes things much better. :D

Pic of resulting Compressor Plot:
http://thumb9.webshots.net/t/66/766/...9usFplF_th.jpg

BTW, if anyone else wants me to do this for them. Just shoot me your specs (bore & stroke, spoolup RPM, and redline RPM) and the turbo (with compressor map link) that you plan to use and I can plot it for you and send you the results via PM. Just looking to help out the community.

Your plot seems awfully high for an engine this small. It may be possible for a turbo that size, but the higher pressure range seems quite generous. I've plotted only slightly better results with an extra liter.

This plot is with a 8000 RPM redline... Thus the higher 'top-end' numbers of flow. Also, volumetric efficiency comes into play, thus I made a guess on my calculations. And I have NO idea what it is on the Miata. If someone knows, please feel free to share. :D

its called, slap the turbo on the motor and drive, stop playing with graphs and fake numbers.

Haha! Very true... I'm still in the building stage of my engine and already have the turbo, so I know it's going to used. However, this might save someone from buying something that would put them in the surge threshold of their selected turbocharger. Also give an idea at what pressure you are getting the most efficient use out of said turbocharger.

Ah, I see. I was assuming a factory redline. That makes more sense then.
:giggle: but but but but benchracing and and and theory!

I <3 benchracing... :D J/K

Also, I'm a chemist for a living, so theory helps me to justify purchases. And yes, all chemists are nerds...

red flag when supra guys talk bench racing!

Only technically am I a Supra guy...MkIV guys disown us because of how cheap, unsophisticated, and poor we are. Their fanboy nutswingers follow suit with "they arent real Supras." :giggle:

Anyways, back on topic. A 30R is a great turbo, but unless you have pretty big power goals, I'd suggest away from it with something smaller. Not having any power until 4500 (as the dyno shows) is extremely annoying. You need to be going for 400-500 to jump up to something that big.

In my application, it will be used on a road race car. It is not an actual GT3076R, but is similar. The actual turbocharger is an INCON GTBB37 that was custom ported by Andreas Miko (SR World). So I would not drop below 5000 RPM at anytime except when coming out of a sharp turn, which would allow me to get on the throttle sooner as I wouldn't have full boost built up to cause traction problems while coming out of the corner. Goal is ~350RWHP by the way...

In that case, it should be an excellent turbo. You'll have plenty of room to move up power wise if you need to. And yes, you'll need to. :D

Thanks for helping me to justify and solidify my findings Orion!

Jason,

Any luck on ironing out what was going on at your VVT switchover?

Couple of updates. I have a pretty serious oil leak that might be a contributing factor. It's leaking right at the vvt fitting where it screws into the block. It's bad enough where it may not be getting enough pressure to allow the vvt to function properly.

I plan on pulling the engine again this week and will be able to really get to the source of the problem. When it's out I plan on fixing that leak, running a single oil line from that fitting to a distribution block to use for my turbo and oil pressure sensors, install the coolant reroute and then I'm going to verify that my timing belt is correctly aligned.

If all goes well it will go back to the dyno to get tuned. Although it does have some mechanical issues that I need to fix before I move forward, I am still hoping that the conservative tune is to blame.

Sounds like you have things well in hand Jason. Glad to hear! I'm with you on the tuning portion of the problem, as the tune itself will not make the car fall flat on it's face like it did in your previous dynos. However, the VVT not functioning properly could infact do that. Hopefully fixing the oil leak is all that is needed to correct this problem. Can't wait to see the updated dynos after the fix. Best of luck!

Any update on the setup Jason? Hopefully all things have been worked out...

Found a few things and hopefully they will fix all of this. For starters I fixed all the little leaks that showed up, paying extra attention to the vvt oil feed. Just got back from a 30 minute drive and it appears they truly are fixed. Replaced the trigger sensor since it appeared to have been slightly damaged. My VVT connector wasn't making a good connection, so I tweaked that a bit and hopefully it will stay connected in the future. Put a fitting on my hotside piping to get a signal for the wastegate. My new logs show it holding steady at 14.4# for now. Right now the AFRs are steady between 11:1 and 11.1:1 at WOT.

I'm only going to be doing some fuel adjustments until I can get it tuned. I will find out tomorrow when I can get it back on the dyno and have my tuner work his magic.

Glad to hear that you seem to have a handle on things and are on your way to getting things sorted. Make sure to post your dyno results when you do get a chance to tune it!

Here's a rough tune at 17.5# while running 92 octane gas. Made a lot of progress last night.

I just replied in your build thread actually... Looking good. Glad it came down to tuning and nothing really mechanical. You can post the boost vs RPM plot here if you want/have it. BTW, what kinda manifold are you running on this setup?

I don't actually have any of the plots except the printout that I scanned. It basically went like this.

Foot on floor at 3000 rpm, immediately 1#. Spool, spool, spool, 4500 rpm 17.5#. 4625 rpm, steady at 17# and it fell less than 1# towards redline. I am running a ball and spring mbc that get's a signal from my hot side piping. When I redo the pipes it will be moved to the cold side and a few other changes to get it to spool and hold better.

Not too shabby for the power you are laying down now. Sure it feels a lot better than it did when it was falling on it's face up top. :p

It was pulling hard on the dyno, unfortunately it rained this morning so I haven't been able to make any street pulls.

Meh, it happens... Just really glad to hear that most things are sorted. So this is still on a rough tune if I read correctly?

It's a solid tune and the AFRs are steady at 11.5 all the way across. I call it a rough tune because we could have kept going with both boost and timing.

Ah... Still not too bad for 17 psi regardless. Makes me want to get mine all together and see what it can do. :D

While looking at your dyno graph... I notice the little blip in power at ~4500 then it goes back up after that, I'm guessing that has to do with the 17.5 psi boost creep and fall-off to 17 psi... Correct me if I'm wrong.

wow these are some great numbers... im currently building up my miata similar to yours but i will have a built 1.8 and running the same turbo. cant wait to have mine up nad running

His is a built 1.8L as well... With a larger bore piston to reach 1.9L. Same thing I'm in the process of doing.

i bought my motor already built so i dont know exactly what is in it. but the owner said its a built 95 motor

That's pretty much it. I'm using a Tial 44mm wastegate that's dumping to atmosphere and even with that there's some fluctuations. I think it will smooth out when I source the signal from the coldside and run a little bit boost. There's a few things I'm going to try when it goes back to the dyno.

For starters, we can all agree that a turbo of this size doesn't really like to see anything less than #17 and would be happiest at 20+. Because of this, I may just start increasing boost and leaving the timing low to see what kind of numbers I get. This might prove to be better than running low boost with a ton of timing. Reality is probably somewhere in the middle for a very streetable tune.

Things may also change a little bit once I drive it on the street. I'm still in disbelief that this dyno pull and the dyno day pull were both on the same setup running at the same boost level.

Based on my compressor plot, it appears that 17 psi should not be a bad place for the GT3076R. As it passes through and stops right in the most efficient island on the compressor plot. 20 psi would be good as well... However, when you get up to 22 psi, you are BARELY hitting the top of the most efficient island of the turbocharger. So I would say between 17 and 20 psi is where the turbo would be the happiest, but you should be able to make more power at 20+ psi to an extent. Just be careful, as at 25 psi you are RIGHT at the surge line when you spool up fully. Granted this is assuming that you spool up at 4300 RPM at ALL boost levels, which is not the case. So you will have a little extra cushion from the surge line at the higher boost levels than seen in the plot below.

Plot based on 1.9L, 4300RPM full-spool, 8000RPM redline:
http://thumb9.webshots.net/t/66/766/...9usFplF_th.jpg

We'll see, should be fun to compare and see where it ends up. Before it's all over, I'm going to have more invested in dyno time than I will in the motor build.

Sometimes that's what it takes to get the best out of your car. Just glad to see things progressing regardless...

What comp/turbine housings?