Power target 450 ish

Hi all. So I currently have a t2871r turbo on my s14 making 360 at 17psi roughly. I'm currently building a forged Sr to eventually swap my engine out with. The question is what turbo do I use.... I'm hoping for around 450hp.. The new engine will most likely have cp pistons, Eagle rods hopefully as close to 9.1 compression ratio, hks step 1 cams.
What sort of power are the T2871 good for at what boost?
Or is it worth swapping out for a new g25-550 or g25-660?
Thanks :)

Sent from my VOG-L09 using Tapatalk

2871 will be near 400hp with your new mods/fresh engine.
i i always think about 380 is a sweet spot for S-chassis as they start destroying themselves when you stick 400hp+ in them. some people have got some disappointing figures out of those G25 turbos on SR20's.

Good to know mate. I've seen a couple just touching 400 on the 2871. I also have a td06 here I could use but I'm guessing the 2871 is the better overall choice of those two.
That's interesting for sure. I'd of thought they would work well

Sent from my VOG-L09 using Tapatalk

I’m running just over 400bhp (flywheel) with a 2871r with a very similar engine build as yours. If I were to upgrade I’d be looking at the g25-550 or 660

Nice man good stuff. I think just over 400 will tide me over till I sort the gearbox situation out [emoji23] again I'm in debate with about 3 options for that [emoji23]
What's the response like on your setup with the 2871?

Sent from my VOG-L09 using Tapatalk

Quote:

---

Originally Posted by madskidsmike

Nice man good stuff. I think just over 400 will tide me over till I sort the gearbox situation out [emoji23] again I'm in debate with about 3 options for that [emoji23]
What's the response like on your setup with the 2871?

Sent from my VOG-L09 using Tapatalk

---

Seems pretty good, not got anything to really compare it to though. Will see if I can find my graph. Gearbox is what stopped me with my car, can’t justify the price tag of the swaps.

Thanks man that'd be nice to see a graph for an idea. Yeah an it's expensive [emoji23] I'm leaning more toward the giken gear sets then a box conversion atm but once the new motors in I'll work out finances ect

Sent from my VOG-L09 using Tapatalk

Osgiken gear set would likely be the route I’d choose too.

Not sure if this dyno reads low or high but it’s a ballpark figure. Will get it on another dyno at some point.

https://uploads.tapatalk-cdn.com/202...bb9043c050.jpg


Sent from my iPhone using Tapatalk

Nice man that looks lovely. Nice and linear and nice spool up too [emoji108][emoji7] thanks mate [emoji123]

Sent from my VOG-L09 using Tapatalk

The difference between a 450hp car and a 400hp car is negligible in benefit and expensive in cost. Consider that a low mount turbo is a bolt on solution, versus a top mount turbo needing a new manifold, elbow, downpipe and service fluid lines.

I don't think the G25-550 would have enough puff for 450hp on an SR, you would likely be in G30 territory. But a low mounted G25-550 would be fast, simple and inexpensive, plus it wouldn't push your gearbox beyond it's natural limit.

A big mistake alot of people who choose the G25-550 make is not getting a large enough exhaust housing on it.

They buy the smallest one available then wonder why it struggles to make power.

Would the g25-660 not be man enough for mid to high 500’s?

I'd of thought the 660 with smaller exhaust housing would be the best choice for the 500hp Mark. That was going to be my option anyway [emoji16][emoji848]

Sent from my VOG-L09 using Tapatalk

Quote:

---

Originally Posted by Chriscooke

Would the g25-660 not be man enough for mid to high 500’s?

---

Honestly I am not sure either, the new numbering still confuses me. But you're also then into new fuel rail and top feed injectors aren't you which is yet another expense.

Quote:

---

Originally Posted by piman2k

Honestly I am not sure either, the new numbering still confuses me. But you're also then into new fuel rail and top feed injectors aren't you which is yet another expense.

---

What do 850cc injectors top out at. Got to be right on their limit if not over it so yeah another chunk of money on fuelling too. This is why I stopped, was cheaper to build an engine swapped track car… kind of.

Quote:

---

Originally Posted by Chriscooke

What do 850cc injectors top out at. Got to be right on their limit if not over it so yeah another chunk of money on fuelling too. This is why I stopped, was cheaper to build an engine swapped track car… kind of.

---

You can get to around 475 with the 850cc SARD injectors.

So many easy options for top feed with the standard inlet manifold these days you'd be daft not to switch to some more modern 1000+cc injectors.

i probably should have said that i have cp 9:1 pistons / eagle rods/ nismo 740's and a 2871r turbo etc.. but stock cams and made 380hp with a conservative map on BP ultimate. but i do have a rb25 gearbox. you blokes are mad if your still on the stock SR box. ive blew them up just accelerating in a straight line on 225 budget tyres.
bmw box would be my choice if i was in the market for an option.