Laur3ns

Keenonracing is starting phase II of it's Nürburgring Nordschleife Time Attack project.

Phase I: sub EUR 9k '94 Miata running 8:01,3 BTG (Bridge to Gantry). Old T25 setup, 5th injector, on the cheap, but fast.

Phase II: suspension upgrade, power upgrade. Target: full lap in 8:00. Current phase I setup is around 8:22

Question: which turbo?

The T25 is dying and we need a power upgrade. Still stock motor.

Setup will be:
MSII
550cc+
Stock '94 1.8 engine
3.6 final drive (yet to be sourced) to increase Vmax

Target HP is 300 crank with as little boost as possible.
Now running 12psi on the T25.

What's the spool on a GT2871R? Fully awake at 4krpm?

Project car:

Laur3ns

hustler

iTrader: (6)

If you're on a stock motor, and run a log manifold, I say gt2860rs becuase the log is restrictive enough and turbo is efficient at like 10psi to make 230 to 240wtq on a Mustang, which still may be too much for the stock rods.

Doppelgänger

iTrader: (12)

blahblahblahNurburgringblahblahblah GTFO ******.



Srsly, I'd say something that has some lag so you can floor it in the turns and just be hitting spool by the time you hit the straights...maybe a 2876

hustler

iTrader: (6)

Obviously you're a test-deficient virgin.

Doppelgänger

iTrader: (12)

Colorblind...yes.

And I will beat your *** on laptimes at Nurburgring.......on GT4

Braineack

iTrader: (62)

rotrex.


but honestly I second the 2860, possibly a 2871.

Laur3ns

Ok, but once that engine is built with forged rods and 8.6 compression?

Laur3ns

That _IS_ the debate basically, 2860 or 2871 - and then .64 or .86 ?
Find me some spool data/dyno plots on 94 head/im/blocks.

hustler

iTrader: (6)

What manifold and DP? I can tell you my begi kit made 12psi at 4200rpm, 15psi at 4400rpm with the big turbine. My AF stuff makes 12psi at 3200rpm, lol. It will also make 18psi at 3200, lol.

Laur3ns

It's a log (HKS?) manifold, 2.5-2.75" dp I presume, no cat.
So, 2860RS .86 makes 12 psi @4.2krpm with that gasket you had?
How would a 2871 .86 compare?

hustler

iTrader: (6)

It will probably spin-up lower because the HKS manifold is a bottom mount (lol) and will flow less than the BEGi manifold. You should really get with the times and build a tubular manifold or buy one from Tim and be a man. I'm making more boost with MUCH LESS backpressure (3" dp all the way back) 1200rpm sooner.

I don't know of anyone running a gt2871 on a log manifold because of reasons above.

Laur3ns

It's HGP then, German. It's angled around 45* between top and side mount.
This project is all about performing an NS8 on a budget. There is no game in buying your average GT-R and doing NS8. We have the driver (not me).

hustler

iTrader: (6)

HGP always had some overpriced but well thought out ideas back when I was into VWs.

Braineack

iTrader: (62)

this is newbsauce's 2871 .64 on a SS log manifold and 3" bellmouth DP 8.7:1 CR .020" pistons on a 1.6L



the blue line is with a 70MM TB and BEGi IM.

TurboTim

iTrader: (9)

woah, less spool with a BEGI im and big TB?! I have always seen same or better spool with these. Interesting.

Braineack

iTrader: (62)

We really didn't tune it that much, the spark during spool still really needs to be played around with. We really didn't add any timing during spool, it drops from 31* to 24* from 101kPa to 128kPa. Then just sat at 20* to 6300 where we brought it back to 24* at redline. So needs work.

But yeah, we were expecting better spool like we saw on paul's platform, but remember this was not a cast IM but one of their welded aluminum ones.



it surely did it's job up top though...even with less boost compared to before.

hustler

iTrader: (6)

Can you put a jankier piece of sheet metal over the COPs?

Full_Tilt_Boogie

iTrader: (1)

Could that amount of power be safely obtained with a bit higher compression with the benefit of better spool?

My vote would go for the 2871 with the .64 over the 2860 with the .86
It certainly looks good on paper, and the benefits on the straight bits should be excellent. The ring is very technical but it has plenty of straights

Braineack

iTrader: (62)

that's a 1.6L and running like 16psi...it's going to have ******* spool compared to a 1.8L, without any benefits of its own.


Compare it to Y8s running a GT2876 @ 9.5psi on his stock '01; that's 10:1 CR and here are two plots of the extremes of his VVT, couldnt find one plot where it was tuned:



With the VVT tuned correctly, he has WAY better spool (red) and the top end (green) holds just as well.

It's 1" 16g aluminum stock...it works.

Straight up heat sink dude, extra cooling capacity.