# 400hp build help



## CTdubbin7 (Apr 15, 2009)

Hey guys I have a 12v vr6 with a t3-t4 turbo boosting 10lbs. Eventually, I want to make around 400hp with some room to grow in the future. I will probably be buying a gt35r. I want to make it reliable first,right now all I have is head studs and lower compression head spacer (fine for a t3t4 on 10lbs).But once I turn the boost up what is the weak point of the vr6? I've heard that the pistons can handle upwards of 500 and that you need to have forged rods. But I've also heard the exact opposite of that. Which one needs to be replaced with forged parts? Or should I just get forged rods and pistons and have nothing to worry about?


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## TBT-Syncro (Apr 28, 2001)

nothing to worry about. lots of cars making 500 and 600hp on stock rods. with head spacers


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## CTdubbin7 (Apr 15, 2009)

I want the motor to last a couple years though at least. Your saying just turn up the boost?


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## huichox4 (Nov 8, 2004)

CTdubbin7 said:


> I want the motor to last a couple years though at least. Your saying just turn up the boost?


as long as you have a good tune and keep up with maintenance you are good. :thumbup:


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## CTdubbin7 (Apr 15, 2009)

Well I want to strengthen it somewhat. I'm thinking arp rod bolts at least. Then buy a gt35r. I just want to know will my gt35r bolt up to my kinetic stage 3 fabrication? Then crank the boost up and get a stronger clutch. Tranny is not too reliable at 400hp from what I've been reading but I haven't seen anywhere what I would need to change in that department. Any suggestions?


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## CTdubbin7 (Apr 15, 2009)

anyone? btw thanks for the input to the guys that have already posted :thumbup:


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## sleepin gti (Jan 21, 2011)

im runnin a garrett 35r, stock bottom end for 2 years. peloquin diff and 6 puck clutch. holds my power fine at 21lbs 501whp... knock on wood :sly: lol however its not a track queen. i dont launch it ever. mainly just a play car for when the college is in and kids have too much money haha


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## CTdubbin7 (Apr 15, 2009)

hahaha NICE. How much power would I be able to squeeze out of my t3-t4 50 trim before I needed to get a bigger turbo? It's only at 10 now, when does it start blowing hot air and how much power can I make at say 20psi through the t3t4. I know I'd need a much better clutch and to beef up the tranny. This car won't be a daily but when stuff breaks it sucks so I wanna keep it on the safe side.


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## sleepin gti (Jan 21, 2011)

im not entirely sure about this but from what ive heard (others feel free to chime in cuz as stated im not certain) i would venture to guess it would be hard to run more than 500 horse through it. but idk for certain.


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## CTdubbin7 (Apr 15, 2009)

I don't think the t3t4 can even make that much. I'm just curious at about 20psi how much power it would put down. Guess theres only one way to find out  It's also a 50 trim which I've been hearing is too small for the vr6  I don't wanna turn the boost up and be screwed.


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## sleepin gti (Jan 21, 2011)

just go to the forced induction thread and read for about a week, then see where you stand


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## CTdubbin7 (Apr 15, 2009)

been reading the FI thread alottt haha I might have to pick your brain when the time comes to really build her up but for now I'm just trying to gather info on what I need.


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## sleepin gti (Jan 21, 2011)

right on :thumbup:


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## V-dubbulyuh (Nov 13, 2005)

CTdubbin7 said:


> I don't think the t3t4 can even make that much. I'm just curious at about 20psi how much power it would put down.


Given that you are probably on a T3 .63, that combined with the 50 trim is stifling your potential to make serious power. Back in the day when that kit first came out it was common to swap the hotside to the .82 and 18-20 psi you were making ~400 whp (but you were stretching it).

You also asked about the Gt35R being a bolt-on for your Kinetic kit. That depends on what config you will get the Gt35 in, T3 or T4 (obviously the manifold in stock form is ported and intended for T3 use). If you opt for a T4 you will be doing some manifold porting. That being said you can probably get a larger T3 and be happy (.82 or 1.06). You should also be considering downpipe config as generally anything around the 1.06 size and up is V-band.


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## sTT eV6 (Oct 26, 2010)

Whatever you decide, buy quality and you will only pay once.
Steve


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## sleepin gti (Jan 21, 2011)

sTT eV6 said:


> Whatever you decide, buy quality and you will only pay once.
> Steve


truth, too many people attempt a "cheap" turbo build. theres no such thing. get it done and over with the first time. then just do general maintenance.


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## CTdubbin7 (Apr 15, 2009)

Thats my plan. I think I'm just going to get forged pistons and rods put in,have the head ported in the process. Get vems standalone and then see where I stand with the turbo I have now before I spring for the 35r. If I can get near 380 with the turbo I have now I'd probably decide not to go bigger but I'd still have the option to go as big as I want with the motor already built.


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## somebodynowhere (Feb 11, 2010)

TBT-Syncro said:


> nothing to worry about. lots of cars making 500 and 600hp on stock rods. with head spacers


This is interesting I've been skeptical of 500~ with a headspacer.

I'm running a 83mm JEs 10:1 with shot peened rods, and built head running n/a for now but planning on hitting the 500 range only worried about head spacer.


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## TBT-Syncro (Apr 28, 2001)

somebodynowhere said:


> This is interesting I've been skeptical of 500~ with a headspacer.
> 
> I'm running a 83mm JEs 10:1 with shot peened rods, and built head running n/a for now but planning on hitting the 500 range only worried about head spacer.


you'll have transmission problems long before headgasket/spacer problems. :beer:


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## CTdubbin7 (Apr 15, 2009)

somebodynowhere said:


> This is interesting I've been skeptical of 500~ with a headspacer.
> 
> I'm running a 83mm JEs 10:1 with shot peened rods, and built head running n/a for now but planning on hitting the 500 range only worried about head spacer.


Ya I understand its been done before but I really wanna be on the safe side. I heard rods are the first to go before pistons. Yet I've heard pistons will go before rods too. Haven't gotten a straight forward answer for if you were to do one or the other which is the better choice to have forged so for 3400 bucks I'll just get the whole damn thing done and have piece of mind.


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## somebodynowhere (Feb 11, 2010)

TBT-Syncro said:


> you'll have transmission problems long before headgasket/spacer problems. :beer:


Oh I know I'm talking engine weak points right now but really 500 is kinda my goal to hit and I don't really want to drop anything more into the engine other than rod and head studs sound achievable? on a 6265? sorry to the op for thread jack


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## V-dubbulyuh (Nov 13, 2005)

somebodynowhere said:


> Oh I know I'm talking engine weak points right now but really 500 is kinda my goal to hit and I don't really want to drop anything more into the engine other than rod and head studs sound achievable? on a 6265? sorry to the op for thread jack


Again, very doable. What you guys are neglecting is that 80% of the "ability/reliability" equation lies in your tune (assuming you have compatible supporting hardware). 500HP has been done repeatedly, just search around a little and you will see the countless build threads and dyno charts. The Precision line of turbos that you are considering will get you into the power range that you are targeting easily on 25-28 psi without taxing the turbo (I personally run them). The billet compressors are very efficient. I'm not sure why this is still so taboo; headspacer, rod bolts, headstuds and a *solid tune* is proven. 

Now if your motor is in poor condition from the genesis this all goes through the door obviously. Guys here are infamous for boosting poorly maintained motors and sh1t boxes in general then having heartache after the first 1000 miles or so (blown heads, fcked transmissions, dead axles, shot sensors, etc).


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## sleepin gti (Jan 21, 2011)

V-dubbulyuh said:


> Again, very doable. What you guys are neglecting is that 80% of the "ability/reliability" equation lies in your tune (assuming you have compatible supporting hardware). 500HP has been done repeatedly, just search around a little and you will see the countless build threads and dyno charts. The Precision line of turbos that you are considering will get you into the power range that you are targeting easily on 25-28 psi without taxing the turbo (I personally run them). The billet compressors are very efficient. I'm not sure why this is still so taboo; headspacer, rod bolts, headstuds and a *solid tune* is proven.
> 
> Now if your motor is in poor condition from the genesis this all goes through the door obviously. Guys here are infamous for boosting poorly maintained motors and sh1t boxes in general then having heartache after the first 1000 miles or so (blown heads, fcked transmissions, dead axles, shot sensors, etc).


spot on!


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