[95VR4]

I am planning on upgrading turbos and I think I want to go with the Gt 357's but would like to know how good they are in comparison to other turbos like the DR's and 13g and 15g's. I want to run around 18 to 20 pounds of boost without sacrificing streetability and reliability. I will also more than likely be going with 720 injectors and all the required fuel upgrades. Please let me know what you think.

 

[Armani]

I say save ur $$$ for a FMIC you won't be sorry! coz if u turn up the boost on the 357 w/o an aftermarket IC ur rear turbo will be toast!

dunno about 15g my stock is 13g and works [email protected] with stock IC.

BEEN THERE DONE THAT!

Think before u spend ur $$$ on a turbo unless u got all the necessary parts (fuel system, Engine Rebuild etc........)

 

[1fastvr4]

95VR4,

If you want to push 18-20 PSI don't get 13G's. That is what I have and they will only hold about 15PSI to redline. I have my BC set for a little over 17 PSI and they boost up to that but drop before I reach redline. I believe that 15G's are only good to about 18 PSI.

Armani,

The intercoolers have nothing to do with how hot the turbos get!! The intercoolers come after the turbos and before the intake. Intercoolers only help reduce the heat going into the intake, not the turbos.

Dean

 

[VR FOUR PLAY]

the 357s are sweet. Get them if you have the money but dont turn up the boost until you get all the necessary parts to run that kind of boost, aka fuel upgrade, more air, injectors. anyway the 357s are bad. i am trying to get them on my car right now but since i just put 8000 into my engine i cant affordthem right now..

just my opinion

 

[wraith]

I agree, you don't need the intercoolers to save the life of the turbo, just the life of your engine if you don't use AI or watch your EGTS carefully. Thats the turbo I am going with in time, just waiting for the LINK that Brian is working on to determone all the other junk I need.

Sam

 

[Armani]

maybe turbos comes first for those who got 9b even GT-R & MKIV get FMIC before going Single/Twin

does'nt the intake have anything to do with turbo to keep it cool ? sooner or later u will be forced to do it!

95VR4
Armani,

The intercoolers have nothing to do with how hot the turbos get!! The intercoolers come after the turbos and before the intake. Intercoolers only help reduce the heat going into the intake, not the turbos.

Dean

 

[pacman3000gt]

well.. in a way... a FMIC 'would' help prolong the life of a turbo IF... EGT's were brought down.

and IF the air intake temp is dropped considerably with the help of an FMIC.. that 'would' kinda help the EGT right?

 

[wraith]

The MKIV guys usually boost very high on the stock motor like 25+ psi, and this is when the big intercooler really helps. The single Supra guys are sort of forced into it as part of the upgrade (they also boost very high). A well designed intercooler may allow us to boost to almost 18psi w/o any AI to cool the charge, but I think thats the end of its ability in terms of anti-detonation capabilities whereas the AI has been proven to help fight detonation all the way to 25 psi in a stock motor. I think in the long run, instead of getting Y-pipes and hard lines and upgraded sidemounts, its better to just go all out with a front mount unless you are heavy into open track. I have been told that some guys overheat when they use front mounts with our cars after many laps. This is when you need to decide what the car will be used for. If your drag racing, Matt and Jack T have already proven its not necessary to do 10s. If cost was no object then we wouldn't be discussing the efficacy of a front mount, but when cost vs gains comes into play, I don't see how you can lose just going with AI.
I am still trying to absorb all the info everyone has gotten through modifying so I am by no means an expert, but I think trying to compare a Supra to our cars is a poor start. The two cars are so different and our needs are definitely different. Guys talking about introducing a laggy large single to our cars defeats every positive attribute our motors have over the competition. Our weight needs solid low-end torque and our AWD driveline system CAN NOT take the hard hit of power that comes from a clutch drop at a power peak from a big single. If we made the quality of power that a Supra makes, we would be in serious need of a tranny replacement. Having a large broad power curve is what our cars are all about. Also huge piping and intercoolers does nothing but force the turbo to work harder to maintain and reach peak boost levels. Also, I take Trevor as a good example of lo-buck proven performance. I believe he is still on the stock coolers and piping doing 11s at relatively low boost settings in street trim and pump with AI. Anybody with a front mount doing any better right now?? I think Jack T has a 94 with front mount and 17gs and he has done low 11s at higher boost levels then Trevor with race gas. Ask him if it made a huge difference with the front mount.

Sam

 

[95VR4]

intercoolers is something that I know I will eventually have to do. I would like to avoid it for as long as possible due to the fact that a front mount is like 3000 dollars. the only reason that I even want to go with the 357's is the fact that they are only like 600 dollars more than most of the others. I think that I would be happier and better off spending the extra money on the 357's. I will also be going with 720's and all the other fuel goodies as well as alchohol injection to help prevent detonation. Does anybody know what the 357's boost limitation is and the amount of boost they hold to redline? I know that if you take all the right precautions such as enough fuel, AI, and watch over everything carefully that our motors can hold a good amount of boost. Matt has already proved that by running 11.0 flat with stock motor and intercoolers. How do the 357's match up against the DR650? From what ive heard the 357 is better. Im not really sure though.

 

[StreetRacer]

1fastvr4.. ehhh wrong, 15G's can hold 22-23 lbs of boost all the way to redline (try it only with race gas). On pump gas, 13-15 lbs is a good, safe setting.

 

[JeffWVR4]

I have GT357's and am very happy with them. I've run them up to 19psi so far, and they held 18 to redline. There's slighty more lag, but you'll feel a HUGE difference on the high end.

I'm running 550 injectors, ARC2 fuel controller, and stock intercoolers on a stock engine with 137K miles on it.

 

[Armani]

What causes it to overheat ? FMIC ? or should I say Stock Radiator? Pitroad solved the radiator problem $1400 Fluidyne for supras $550 !!

I have been told that some guys overheat when they use front mounts with our cars after many laps. This is when you need to decide what the car will be used for. If your drag racing, Matt and Jack T have already proven its not necessary to do 10s. If cost was no object then we wouldn't be discussing the efficacy of a front mount, but when cost vs gains comes into play, I don't see how you can lose just going with AI.

 

[Jeff Lucius]

1fastvr4.. ehhh wrong, 15G's can hold 22-23 lbs of boost all the way to redline (try it only with race gas). On pump gas, 13-15 lbs is a good, safe setting.

If a 6G72 TT has 100% VE at 7000 RPM (standard "redline") then 20 psi boost would represent about 892 CFM or 446 CFM per turbo - a bit beyond the range of 15G class turbos. Of course if the engine were only operating at 78% VE then 808 CFM (about what two 15G can flow) would flow at 23 psi boost at 7000 RPM.

So what are you bragging about? A poor VE at 7000 RPM in order to get 23 psi boost? Too bad you can't get only 18 psi boost out of 15Gs cause that would mean a nicely built engine.

Thank god the secrets are kept by AAM!

 

[hobbit382]

sorry for the stupid question Jeff but what does ve mean? and what would we have to do to get a higher %

 

[Gatecrasher]

I'm the wrong Jeff but,

VE = volumetric efficiency

 

[Joe G.]

Good post Jeff L., but few will fully understand it even though it's been explained many times over.

 

[Trevor]

My unported/unclipped 15G's can hold 20psi to redline.

 

[MagnumForceGTO]

The difference on my 357's at 18psi compared to 22 psi is substantial.

 

[Red Bomber]

Same here...

After fixing a bunch of problems, I finally got to feel the difference between 16 and 22psi. WOWOWOWOWOW!!!! I am in agreement with Magnum on the GT 357's.

They REALLY like 22psi.

Travis.

 

[quick]

Hey JeffWVR4,

What kind of temps. were you getting from you EGT's at 19PSI with the 357's and 550 injectors. I boosted at 17 PSI with 550's and got ~900 degrees . I'm at 6100 ASL and went lean!! So I opted for the 660's.