My 99 2.4 g4cs build up

[DsmGSXakaEvo]

Ok So I have been a member since November 2010 and have never posted a single post I have bought things a researched countless builds on these forums, I only have a few questions. I own a G4CS with a 1G ported head with a eagle forged crank aluminum rods CP pistons 1mm over sized valves both intake and exhaust 280 cams intake and exhaust with springs and retainers a JMF intake manifold with 75 mm throttle body, custom T4 tubular exhaust manifold divided with twin Tial 38 mm waste gates with 1.7 bar spring and a Morsol oil pan. Now question is simply this, this block was made to handle 45+ psi but after really thinking about it 45 psi is different from turbo to turbo for example 20psi in a 16g is no where near the same as if you had a gt35 because of the amount of air flow. I plan to run a TRUE GARRETT GT37R (if you research gt37 you will find that only one exist and it is from Garrett there are hybrids but not a true gt37) on about 32 psi that got me thinking with the amount of air flow do you think i will need to run two bov's to release the pressure so i don't get compressor surge. My plan was to use a Tial Q bov because it is supposed to have 60% more flow than there leading one now or run two 50 mm ones because I plan to upgrade to a gt42r also from Garrett with in the next year

Next question is what transmission should I get my approximate power will be close to 650 - 700 now i know horsepower is not torque and torque is what moves the car is car will be driven in auto cross and some road courses with the gt37

please no remakes like another dreamer here or if you have to ask you shouldn't try to build it because once in time someone had to ask a question. These in not a questions like what do I need for a 10sec car or what do i need to make 1000hp on the street. I know what it takes just would like to have some input and advice or someones first hand knowledge.

Thanks for any input in advance

 

[Talon2139]

Hi there and welcome to our forums, first off the bov, if you have it hooked or will have it to stock, it will be recirculating; so perty much the flow of the bov doesnt really matter, it just has to open when you need it to, like everytime you let go of the throttle, since it works off vacuum. So just run like one, you can run two but that would just be kindof rediculus.

The transmission I would just take your awd trans, and get it upgraded at TRE, that is a trans shop in Kalamazoo, Michigan.

Well, i hope that answered some of your questions. good luck with the build!

 

[snowborder714]

A 37r is not going to be any fun on an autox course. A road course would be a different story, but that turbo will take too long to spool for autox.

 

[50trimgst]

Every one I talked to that runs dual bov runs the mustang tb. So as long as your not running it you should be fine. Transmission builds well idk where to tell you to go on that. A friend of mine runs that 2.4 and shatters 5th gear all the time even with a shep 4.

 

[Absit]

A 37r is not going to be any fun on an autox course. A road course would be a different story, but that turbo will take too long to spool for autox.

This. Even on a road course it could be a pain.

 

[phizzalot]

Sounds like you have a pretty nice build in progress there...
Ia'm no where close 700/hp/tq but I would second TRE for a nicely priced capable transmission.
I would also call around to shops like Magnus Motorsports or ShepTrans to see what type of deals they can offer and warranty they have on there products if you push past there products limits.

Good luck.

 

[DsmGSXakaEvo]

First off thank you to everyone so far for the replies I have since looked in to tre transmissions and shep transmissions. I am running a mustang throttle body 75mm so I will look in to the dual bovs more. I understand they work on vacuum my question was whether or not a single bov would release the amount of air required for a setup like this. Thank you for your replies and as I finish my build I will post more things up.

The gt37 I was told by Garrett has the spool up of a gt35 but the out put of something similar to Precision Turbo 6262 and with the divided t4 into a twin scroll turbo the spool time should be reduced and that the block is a 2.4 will help as well because the added displacement will flow more air into the turbo, hopefully making the turbo spool faster.

For 50trimgst could you please put me in touch with your friend that runs the 2.4 and keeps breaking 5th gear

 

[snowborder714]

The gt37 I was told by Garrett has the spool up of a gt35 but the out put of something similar to Precision Turbo 6262 and with the divided t4 into a twin scroll turbo the spool time should be reduced and that the block is a 2.4 will help as well because the added displacement will flow more air into the turbo, hopefully making the turbo spool faster.

And when did they tell you full spool on a GT35/37 would be for an average psi?

1. That turbo doesn't get into it's efficient range until I'd say 25+ psi.
2. Twin scroll will help, but I'd only account for a few hundred RPM's.
3. Same with the 2.4.

I personally would like to see full spool on my turbo by mid-3000 RPM's for autox. Anything later and the car will seem like a dog out of corners. Think of how low speed/gear wise you need to go in some of the tight 90*+ corners, and then coming out into a short straight before another corner. Your turbo will not spool well in situations like that.

A road course will be a bit different since you shouldn't really have the car below 3000 RPM's or so, and you won't have too many technical sections or really tight turns. Drew (owner of the white TA car you see above) runs a turbo of about that size with a 2.4 block (no twin scroll that I know of) and does great. But I doubt you'd ever see his car on an autox course.

 

[DsmGSXakaEvo]

I was told spool up should be about 3750-3800, now i'm no turbo expert by any means, this is why I started to ask questions. road racing I think I will be fine but you are right if I have to drop below 3200rpms in auto cross the car is going to be as slow as a snail crossing the road. I will only be auto crossing this car a few times a year anyway, it is really for road racing sorry i didn't mention that up top. And when I put the gt42 on it is only to beat my friends supra in the mile. he has 617 hp from a single t67 on e85.