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89 Supra Turbo M/T
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Discussion Starter · #1 ·
Hoping to lean on you guys out with more experience.

With my EBC turned up, I'm barely getting more boost. I've leaked tested the intake piping up to 20 psi with no leaks. I'm convinced part of it is my "bad" style CXracing or driftmotion intercooler. My wastegate opens up at 7 psi (tested with a hand pump), yet it needs 80% duty cycle on the EBC to get 13.5 psi of boost. That really doesn't make sense to me. I have a fairly free flowing setup (BIC divorced DP, 3" exhaust, 2.5" intercooler piping). Also, targeting above 400WHP so might as well address the sub-optimal intercooler.

Here's what I'm thinking about....

This is the budget option from silicon intakes. They claim less than 1 psi pressure drop and good up to 600hp


The other one's I'm considering are treadstone. One is rated for 500hp and the other 720hp. The smaller one is rated for 1.5 psi pressure drop. No specs on the bigger one. The smaller one is appealing for packaging and price reasons. Kinda surprised about the pressure drop but maybe that has more to do with the test itself? Maybe size isn't really much of an issue here?




Which one is the best way to go on a 57 trim setup on standalone aiming for 400 WHP+?
 

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1988 Supra GT Targa 5spd R154 7MGTE built
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I have the DM one, it made 450hp/475 tq at 1.1Bar with an EBC, external wastegate with a 7-8psi spring as well. That was on a Holset h1e billet 60/64 22cm3 turbine housing. We maxed out the duty cycle on the MAC valve to reach 15-16psi.

SP requested I put in at least a 1 bar wastegate spring before retuning, I've got a 1.4bar spring in my toolbox
 

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boost'en down 101
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Out of those intercoolers I'd go with the treadstone. The fins are much more dense than a ebay one. When I first swapped my car I used a 12x24 ebay it worked for when I was making 400's. Once I got into the 600's and had a standalone I got to see my iat's were going pretty high by the end of a 1/4 mile pass. Switched to a treadstone 1000hp intercooler and haven't had a problem since in the 800's now.

The thing is though I don't think the intercooler is causing you to have such a high duty cycle. I was running 33psi through my ebay one granted it didn't cool great at the power but it never caused a boost control issue. It's most likely the wastegate getting blown open. Ideally you don't want to go more than double your wastegate pressure. You can try shimming it but best bet is to get one that you can change the springs out. That will give you the best boost control.
 
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1988 Supra GT Targa 5spd R154 7MGTE built
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I can say when I do a hard pull with the DM intercooler I see my IAT's drop, again I'm in 400's plan on going for the 6 mark come spring so can share feedback then.

I do agree this seems to be a wastegate issue.
 

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Discussion Starter · #6 ·
@CTsupra , hopefully not too much additional piping work, but I'll definitely share the info if I go that route.

@black89t , that was my first thought. I did pull the wastegate and test on the bench. It will start to crack the actuator a little under 7 psi... so maybe my boost pressure makes sense in light of that. I have another wastegate on the way that I'll be putting on. Going to try a 2 port wastegate with a 4 point solenoid just because I have the opportunity to.

@Z06gette , do you notice any performance decrease above 400 hp? Lots of people reporting some big pressure drops with that IC.

If I do got with another IC, I'll probably go treadstone TRV185.
 

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1988 Supra GT Targa 5spd R154 7MGTE built
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I’m referring to the spearco style same side intercooler like the one you posted the pic of, not the opposite side one with the 90* outlet that they also sell. Just to be clear. I have had no reason to do a pressure loss test so I can give no data in that regard.
I can say I ran my intercooler piping as direct as possible. Does length pre and post intercooler play a role in pressure drop?
I know my IATs are decreased by the intercooler at my current hp and boost levels.
With the given intercooler, changing the waste gate spring will allow me to run more boost and test further.
 

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1988 Supra GT Targa 5spd R154 7MGTE built
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That’s not the one I have. That one is not a good design. The other one has the end tanks horizontal top and bottom and the fins vertical so the air flows from one tank to the other, not just across the core.
 

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I didn't see it touched upon, but is 400whp doable with a 57 trim CT26?

Also, duct the thing! ;)
 

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89 Supra Turbo M/T
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Discussion Starter · #15 ·
Ducting sounds like fun! Any pics for inspiration? I have some bumper stuff waiting to be put in (S2 airguide, fog light ducts, and grille guides). I could probably do something with that.

I was told the Albeart Meade 57 trim with a clipped wheel should get to 400 WHP+. We'll see. Others have reported dyno numbers in that region. I've seen several posts in the high 300's at 16 psi and these are apparently efficient up to 20psi. I might run out of pump though (walbro 255, 40psi base pressure, 650ccc injectors).
 
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