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Discussion Starter #1 (Edited)
Hello all,

here's the story... I am building my 2nd gen 1991 JDM 3SGTE daily driver. I have done the following so far:

Bottom end:
-CP pistons (.040 oversize and 9.0 compression ratio)
-Eagle rods
-ACL race bearings

Top end:
-The intake side of the head was already ported by the previous owner
-Brian Crower Stage 2 cams 264/264 low lift (8.74mm)
-Adjustable cam pulleys
-I have decided to have a valve job done, but keeping the stock valves and springs
-I am not a reving fan, I usually stay between 3000 and 6000RPM
-Cometic multi-layer head gasket

Others:
-Walbro 255lph fuel pump (already installed)
-DIYPNP ECU (already installed)
-Greddy side mound larger intercooler
-I want to keep the TVIS since it helps low end torque
-Injectors and fuel rail not decided yet...

OK, here's my next step:
I am looking at making 350whp (400 crank hp) with 91 octane pump gas at around 20 PSI. Am I in deam land ? I was looking at the GT3071R, but all the threads about this subject are old, dyno charts images are no longer available and I'd like to know if there are better options now in 2017 to keep the spool time as low as possible. I would like to spool to full boost (20 PSI) at around 3500 RPM. Am I still dreaming ?

I was reading that soo many other turbos can do 400hp, but I'm not sure about 2871 or maybe others you may suggest ? If I have to choose between low turbo lag and top power, I will choose low lag at the expense of top numbers. So any suggestions are welcome.

I know that there is a world of difference between paper specs and real world. That is why I am looking for people with experience in real component applications. If you say that the GT3071 is not the right choice for me, please suggest what you think would better suit my needs.

Thanks !
 

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I think you are asking for trouble at 20PSI and 91 gas. All those cars making 400 most likely making it on E85 or at least 93.
 

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Discussion Starter #3
What is the highest boost (PSI) I can go with 91 octane before before it starts to knock ? And around how much power should I expext ? I only want to use pump gas, so what could be realistic ? Should I stick with the 3071 then ? Or go smaller ?
 

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What is the highest boost (PSI) I can go with 91 octane before before it starts to knock ?
That question does not have a simple answer, since you are working in a multidimensional envelope. A short answer is that as you go higher, your margin of error gets smaller. It would make sense to start low and get some experience tuning what you have, and move up as you see the room. The limit will depend on how much risk you want to take, as much as the absolute capacity of the hardware.
 

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The GT3071 should be able to make 350whp on pump gas on that motor given the cams and head work. Maybe add a re-plenumed intake manifold, then you should have no trouble. Should be able to do it at about 17psi.

Here is my dyno from when I had a similar setup. Biggest differences are I had a 2.1L stroker, and oversized valves.

http://www.mr2oc.com/50-dyno-discussions-postings/424116-ats-racing-gt3071r-manifold-vs-stock-dyno.html
If the images don't show up for you, get the photobucket fix for either chrome or firefox.

These were at ~20psi on pump gas with water injection, but also at almost 5000ft. So roughly 3psi was compensating for the altitude. Others with similar setups have made similar power at sea level and ~17psi.
 

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Discussion Starter #6
That power curve looks great between 4300 and 6000 rpm. Was the TVIS still there ? Any chances or tips to have the power 500 rpm sooner ?

I am affraid to go with water/meth injection. I read so many scary stories on forums. I know I could use a secondary map in case the water/meth tank is empty or if I loose pressure in the injection line. If the whole setup would only give 30hp out of a total of 350, I don't think it's worth the risk. But any comments on this would be appreciated.

Thanks again for the great replies
 

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I agree with the others, low octane fuel will be the limiting factor.

If installed and maintained properly WI is as safe as its gets. I'd be more relient on having it as a safeguard rather than trusting a local pump station to deliver high octane fuel. Think through your system and how you want to provide a fail safe system. As an example a simple pressure switch can be installed on supply line to warn (LED)or protect engine (timing retard) if there is a failure. Combine this with an accumulator tank and it will deliver enough water/meth to supply 1 or 2 high boost sessions. This covers any failure apart from blocked line or nozzle.

On the turbo selection, spend some time and look around. Technology has moved very quickly in this area and new high flow 9 blade turbines along with billet extended tip compressors deliver great performance over a wider range. If your willing to do some of the work yourself matching exhaust and service lines there are several real choices available. One example;

TOYOTA 3SGTE Celica ST185 205 GT4 Twin Entry CT26-GT3071R Turbo - MAMBATEK TURBO

jim

jim
 

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That power curve looks great between 4300 and 6000 rpm. Was the TVIS still there ? Any chances or tips to have the power 500 rpm sooner ?
Smaller turbo. Or Bigger engine. Yes, TVIS was installed and functional / controlled by the aftermarket ECU. You may notice I speak of this setup in the past tense, that's because I swapped a 2GR-FE v6 into the car last winter. It's not as much peak power, but that power curve looks like this:



Sorry, probably not helpful, since you are already pretty far down the built turbo path.

I am affraid to go with water/meth injection. I read so many scary stories on forums. I know I could use a secondary map in case the water/meth tank is empty or if I loose pressure in the injection line. If the whole setup would only give 30hp out of a total of 350, I don't think it's worth the risk. But any comments on this would be appreciated.
I never felt like I was really relying on it, or making a ton more power because of it, more just using it as a safety net / supplemental intercooler. And as long as you have good knock control in the ECU, you can rely on it to some degree. I mostly ran plain water in mine.
 

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Discussion Starter #9
So if I will be limited by the 91 octane, I will not really use the 3071 at its full potential then. Is it a waste of money in my case ?

Also, I looked at that Mamba turbo CT26 and to fit a 3071 wheel in a CT26, I wonder how much wall thickness there is left on that housing...
 

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Discussion Starter #10 (Edited)
I have just found out about the GTX2867R, same flow as the GT3071R, but better spool. Any one out there have experience on a 3SGTE ? Is it worth the extra money ?
 

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Discussion Starter #13 (Edited)
OK, it was a while ago, but the engine is finally ready with the GTX2867R. I have used CP pistons with rings, Eagle rods, ACL race crank/rods bearings, stand alone ECU, 800cc injectors, the head was ported and I changed the cams for Brian Crower 264. What puzzles me is the Tial wastegate... I read in the doc. that it is water cooled. Where should I tap in the cooling system?
 

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Discussion Starter #14
OK, that's it, it's in. And it runs... and it does not make any weird noises... So far, so good. At first I had to find the new cranking values for the new cams, lower compression and bigger injectors combo, but it's fine now, it just took some time. At first, I placed the BC264 cams at 0 deg in. and 0 deg ex. and was getting 17inHg of vacuum instead of the 20 I was getting before and did the break-in plus a few non-boost fuel map changes. The motor performance was very poor. After dialing the cams to 3 Deg advance on intake and 7 deg retard on exhaust, I was only now getting 12inHg of vacuum, but it pulls good. Can't wait to go on the dyno for the final tuning and I will post the GTX2867R spool time video.
 

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Looking good and a long time coming. Not sure why wastegates are advertised as water cooled as really can't see the point unless your very close to exhaust outlet. Hope you get some decent numbers on the dyno and more importantly drives the way you want.
 

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I think you are asking for trouble at 20PSI and 91 gas. All those cars making 400 most likely making it on E85 or at least 93.
It's just a question of the engine flowing enough. An SR20DET (a little better flowing head than a 3S-GTE Gen 2 it seems) can do 400 rwhp with like an EFR 7163 or GTX3071R on pump gas (the EFR is pretty easy actually since it behaves similar to a GT3576R with way lower inertia). A GTX2867R can do 400 rwhp+ flat out, but I don't know about on a 2L with a meh flowing head and 92 octane pump gas. Maybe, but it'll be on the limits. The compressor and turbine are both struggling to flow that much.
 
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