Help me decide, I want opinions...

[jr_ss]

Ok, I'm going to sound alittle bit hypocrictal here asking for help, when I know it's all about what I want but, it's so close I need an outsiders help.

I'm trying to decide what turbo to run on my build. I don't want to go top mount, nor do I want an externally gated setup, so I've narrowed it down to 3, the GT2871R .64, .86 and the FP 20g all bottom mount of course (sleeper look)... They are all comparable turbo's with the 2871R .86 and the 20g being closer in terms of spool and capable power levels. My problem lies in my build. I'm building a 9.1:1 motor with a slight port on the head and exhaust mani (mainly smoothing out of the ports and casting marks), which will help with spool times of all 3 turbo's.

Will I out flow the .64? Meaning, would it be better to get the .86 knowing that I'll reduce spool times because to the nature of the beast? The 2871R .64 was my first choice due to the fact that it can make 400rwhp and it is very responsive. But when I think about it, with my build I should be able to spool the .86 at or around the same time someone with a 8.5:1 motor should be able to spool the .64. I'm aiming for 400rwhp, but if I make more so be it. Somewhere, some how, my build took a turn for higher hp than originally intended. I guess I could get the bigger turbo, just to have a cushion incase I want more power (which I'm sure I will) down the road.

The 20g I think will outflow the 2871R in both trims in the higher boost levels, but sacrafice spool time (minimal). I've seen 20g's push close to if not higher than 30psi (not that I'm going to take it there). Where as the 2871R's aren't capable of as high of psi levels, but will spool slightly faster than the 20g.

My build:

S14 w/ VCTToda 264's w/ 10.5mm liftSupertech DVSMild port on headJe 8.5:1Eagle rodsBlock/Head decked to bring comp to 9.1:1Cosworth main/rod bearingsARP head/main/rod boltsCosworth 1.5mm HGNX2000 70mm TB740cc injNismo FPRATI dampnerTurbo 1 of the 3 above

I'm sure I've missed something, but that's the basics and should help determine what turbo I should run. Thanks for everyone that will and has looked.

Glenn

[Kalypso]

how do you want to drive it? auto-x, highway rampaging, drift, rally?

I vote the 20g, because it baller, the .64 seems like a better fit with a light port.

but my experience comes only from what ive read.

[jr_ss]

I'd like a responsive setup... I don't want a lag monster... I might just run with the .64 and call it a day... I can always upgrade later.

[srdub-t]

yea just go with the 63 ar for now and when you get sick of it ull prolly find somone on the forums that would do an even trade for ur housing... or you can just buy the housing lata if noone wants to trade

[Kalypso]

that wasn't so bad.

good luck with the build, make a thread with somephotos once you've got it together.

[kentuckyslider]

If you want a bad a$$ street car and not a drag car go with the 2871 .64 ar. The FP green is the max for a T25 flange and it will spool at least 400-500 rpm later than the .64 52 trim GT2871. With the toda cams and low lift you will have a beast in the mid range, (I know because I do). I beat up on a STi with a FP green 20g every weekend at the track without my cams. You should be in the 400whp range and if you go with the 4.36 R&P like mine it will be a beast.

[mistamacadamian]

a 20g will def get you 400+ and from what i have been told spool time isnt too bad on it. It doesnt matter about spool tho b/c you will still be pushing 12/13psi when your spooling still making good power then you have that 4500-7500rpm range to rape ****. i was gonna say if you had a built head you could rev to 8500 with that 20g. Its a bad *** bottom mount set up.

[Kalypso]

The FP green is the max for a T25 flange and it will spool at least 400-500 rpm later than the .64 52 trim GT2871.

fp green? thats the first time ive heard of it

[homeslicej2]

If you want a bad a$$ street car and not a drag car go with the 2871 .64 ar. The FP green is the max for a T25 flange and it will spool at least 400-500 rpm later than the .64 52 trim GT2871. With the toda cams and low lift you will have a beast in the mid range.

My thoughts as well. With that cam setup, your head is better matched to the 2871 .64

[jr_ss]

I know the .64 will pull way beyond 7500, which is a good thing. I may be upgrading the 00-01 HLA's w/ the 98-99 rocker arms from the DE's as they have deeper recieving sockets for the HLA's. I was hoping to rev close to 8k, but it's all about where power falls off. If it falls off at 7600, I'll put my rev limit 100rpms higher and leave it there. Everything will be broken in on the dyno, then power pulls after that's done... If I make 375+ I'll be happy, it'll be safe and reliable and shouldn't have any issues with it.

Thanks for everyone that shed some light and added their input. I'd like to keep this open, and get more people to chime in.

[SleepR 240sx]

You won't outflow the .64. If you run some JWT S3 cams you should be able to hit close to 400rwhp at 20psi. The .86 is not a bad turbo but I don't see a reason to run it on your setup. Less responsive and you don't need the slight advantage in top end horsepower. Honestly the gt2871r is IMO one of the best turbo's for the SR. Very easy to make power with and relatively cheap. What's your fuel setup looking like...didn't see it above might have just missed it though. At least 550cc's, 740cc's if your looking to upgrade in the future. Tune it right and you should hit 375whp no problem.