sixshooter

iTrader: (12)

I made 262whp on an actual dyno at 16psi with a GTX2867R with a .86 hotside. So 320-anything at 16.5 sounds superlative.

nitrodann

The GenII GTX2867r is good for around 55lb/min. Approx 550hp on gasoline or 600 on E85.

nitrodann

Hi six,

I wonder where your HP went at 16psi because that sounds pretty average to me, and I dont mean that as an insult but a good opportunity to pick up easy performance. Without making me read your whole build thread again for a refresher, is there anything you think might be contributing? I do a LOT of full turbo conversions drive-in drive-out, and we usually see 260@13psi on a GT2860rs 0.86 on an NB.

I would be willing to bet that your NA8 cylinder head is keeping the turbo way out of it's efficiency range at that boost/power. (I take this back now I have had a fresh look at the comp. map)

What do you think? It has got to be your cylinder head, right?

450hp @30psi is 450whp@approx 45psi absolute. 10hp/psi. If you're on 16, thats 30psi absolute which should be 300whp.


Dann

sixshooter

iTrader: (12)

Log manifold, NA8 head, intake, and cams.

NB cams would be larger.

Since then I switched to a tubular exhaust manifold.

Ted75zcar

iTrader: (2)

With a PR of ~2.1, mid to mid high 200s sounds totally reasonable to me on an NA8

nitrodann

Yeah I think it's the cylinder head also.

shlammed

iTrader: (8)

the manifold does change a bit too (mostly in hp reigons and not torque areas) a VW customer of mine sent me a text 2 weeks ago "manifold did well, there is no more soft spot in the mid-upper range. thanks." came from a cast manifold to a ramhorn type manifold. no dyno to back it up, unfortunately but most people don't re-dyno for a manifold and downpipe change.

beyond that, yes the cylinder heads do quite a bit better with the nb style casting.

ridethecliche

iTrader: (2)

Err... so most people don't retune for that either then? That kinda baffles me a bit.

nitrodann

He is right that most people across all communities dont. But it isnt the right practice. I like a quick run for a sparkplug heat range change or air filter swap.

Dann

shlammed

iTrader: (8)

yeah, its not common people go back for a retune with the same turbo after a manifold/downpipe change.

there are a ton of people out there with OEM turbo cars that just slap on a bunch of parts and only tune it to get rid of a CEL or something to that effect.

18psi

iTrader: (76)

this is news to me, considering most modern turbo OEM's will either pull power, or freak out, or even blow up with increased breathing without tuning.
unless you mean old(er) cars

sshamrockk

2012 Audi a5(winter beater) here. i got an off the shelf tune when i got a cold air intake. Got a catless downpipe and havnt tuned it again in 2.5 years, gets driven hard and hasn't skipped a beat. is it optimal, probably not could def make more power now but afrs are great. I think every manufacturer is different.

Mpliki

Also something that i cannot understand. I loged the pull on the dyno with msdroid and spool was not the same. It was slower. Normally i get 16 psi at 3800. On the dyno i hit 16 psi at 4100.... Can anyone enlighten me? Dyno is maha lps3000

shlammed

iTrader: (8)

you need to stop playing with subarus.

sshamrockk

This is typically how turbo cars react. There's less load on the car, hence the slower spool.

andyfloyd

Your log manifold will hold you back dramatically, as will the NA head but I think going tubular your going to be picking up 20-25whp. Different car but my s2000 made 372whp with a log and then a switch to a tubular made 421whp both at 11psi on a 3076R. Thats insane.

18psi

iTrader: (76)

they're not all bad