2871R for 3071R

[str8sidewayz]

whats up guys? this may be a stupid question. but i have a garrett 2871 on my redtop currently. if i wanted to upgrade to a 3071 will my manifold/downpipe/extension fit on the 3071? or would i have to get diff stuff?

[burnsauto]

ive seen it come down to the manifold design. and i've heard you need to trim the engine mount a little bit to make the housing clear.

[osus14]

i am goign to be doing to the samething upgrading my gt2871r to a 3071r. I have done a lil research and read some manifold will clear the mount and some will not and you will do a lil trimming. It isn't hard to upgrade and other then the engine mount clearance you can still use your manifold turbo extension etc.

[burnsauto]

yeah cheaper manifold designs like the turbo xs one doesnt clear. The full race prostock one should though. So just spend 1k and you're good ;) hehe

[KA-T_240]

To get the GT3071R for a bottom mount, you are going to need to get the T2 setup. If you want the T3 you will have to step up to a top mount turbo manifold.


What are your goals for the car, powerwise? And what do you use it for?

[Z U L8R]

gt30/76r or gt35/82r PRECISION FTW!

Dave =]

[str8sidewayz]

ooh sweet thanks alot for the help guys! well i have some manifold that came with the car i know its not stock but idk if its a good one or not. soo im just gunna try it and see if it fits. if not ill go from there.

[str8sidewayz]

now maybe i can find someone who is willing to trade.. maybe someone looking for a dff setup.

[osus14]

I heard that the megan racing manifold will clear it as well.

[1997silvia]

if either of you guys want to sell you 2871r let me know what ar they are and sold

[guitaraholic]

Ok, I know this is bringing something back from the dead, but just wondering about something. From what I read, the only diff between the 2871r and the 3071r is the turbine (exhaust) side. Yes I know its uses a t2 flange instead of a t3/t4, so it is more restrictive (will get to that later) The compressor wheel is the same size.
Now I have heard that once you build up too much pressure in the exhaust it actually begins to choke the turbo and you lose power, so you would choke on your smaller turbine wheel and smaller exhaust flange. But wouldn't an external wastegate solve that problem, because you could set it up so the "excess" can bypass the turbo all together so the turbo doesn't get a chance to choke on it.
Given this information and that it has been stated many times here that the 2871r spools sooner than the 3071r. Wouldn't it make the 2871r the better choice, if you just welded the wastegate and went external. I would almost think that even bypassing some of the exhaust gases off the 2871r and the T2 flang, you should be able to keep the compressor wheels at the same speed as a 3071r at higher RPMs.

[slider2828]

Yes.... on bottom mount, don't bother 3071r, because like you said, it really chokes out the turbo. Pretty useless. Go top mount with wastegate, and you have a baller setup with a big snail on top.

[GSXRJJordan]

Yes.... on bottom mount, don't bother 3071r, because like you said, it really chokes out the turbo. Pretty useless. Go top mount with wastegate, and you have a baller setup with a big snail on top.

Well said. However check out Steve Shadows' Shadowerks Tunes thread, he's got a guy in there with a bottom-mount 3076r I believe that made a shit-ton of power. Would he be better off with a top-mount? Probably... Does that mean the T2-flanged 3071 or 3076 is a bad idea? Nope.

[guitaraholic]

Ok, I'll wear a flame suit for this question. Is the only reason for going top mount because of fitment issues? Other than the fact that you can get an External WG on top mount (is it possible on bottom mount?), which should help your spool-up time and improve flow.

[codyace]

Well said. However check out Steve Shadows' Shadowerks Tunes thread, he's got a guy in there with a bottom-mount 3076r I believe that made a shit-ton of power. Would he be better off with a top-mount? Probably... Does that mean the T2-flanged 3071 or 3076 is a bad idea? Nope.

The one that was makin 37x? That's an easy 400 whp car on a dynojet...pretty good numbers, but the same can be achieved with better response with a 2871r ;)

(Not hating on Steve K, he's man loveable)


I'll always maintain, Bottom mount = 2871 Top Mount =30xxr

[GSXRJJordan]

Ok, I'll wear a flame suit for this question. Is the only reason for going top mount because of fitment issues? Other than the fact that you can get an External WG on top mount (is it possible on bottom mount?), which should help your spool-up time and improve flow.

Basically, that's correct. Bottom mount = better weight distribution (turbos are heavy!) and better cooling (air exits behind the engine/to the bottom of the firewall).

You can certainly have an external gate on a bottom mount setup - Codyace has one. But it gets very difficult with a tubular mani (he runs stocker because he's poor and gay and stuff :) ) - much more room for gate and associated piping on a top-mount.

[guitaraholic]

Well, I have seen in a few places where a 3071r can give you around 450whp (really pushing it), where the 2871r you have to push, tune and pray for 400whp.
If the compressor turbines are the same on the 2871r and the 3071r, and they are both spinning at the same speed (do they?), what difference should it make on the turbine side (given you went external on the 2871's back side wasn't being choked.