Well today i got my car dynoed for the first time since i have been boosted.
the car made 266whp & 240wtq at the peak. at 18psi
seems very low for what it is, maybe you all can help me figure out the problem.
the tuner (JFK7 told me that it is more than likely my manifold and downpipe combination, in other words, my whole setup, lol

here is the setup:

Engine:
D16y8 block
d16z6 stock head
Vitara 75.5mm pistons
Eagle rods
stock d16y8 intake manifold
DSM 450cc injectors

Turbo components:
Precision SC50 turbo (50 trim)
.48/.60 A/R
2in piping from turbo to IC
2.25in piping from IC to TB
Stainless log manifold
2.5 inch a/c compatible dp
TiAL 38mm wg
TiAL 50mm BOV

 

The first 2 thing I would change is put a y8 head on it, and the second thing is get a ported z6 intake mani from Chris the mod.

 

Exhaust size? Do you have the wg dumping straight infront of the compressor side of the turbo?

Get a bigger turbo or more boost

 

If he can get it cheap I say he goes for it. It has more to due with correct timeing then anything else, it will also bump his comp a hair.

 

For a boost appilication, the Y8 head sucks ***. The quench on them doesn't work for boost at all, and the fact that they flow like ---- is another. No way in hell would i swap the y8 out for the z6.

It be honest i don't think 266hp is bad for a very mild d series at 18lbs. yes he'd make more hp by swapping out to a .63 turbine housing, getting rid of the log, and going 3 inch dp. If he did those 3 things i would bet he'd get over 300 but at that point he'd really need to go to a good cam, which would give him as much gain as anything else.


---- it, just run some more boost......

 

IIRC one of the guys on turbod16.com ran the same turbo up to 19psi on his z6 with slightly higher CR, I think a stg2 cam too, and made 325whp. I do think he had a 3" DP though, no cat, and likely had all 2.5" charge pipes. I think he also used a ramhorn, so like your tuner said, your whole setup is the problem

Your best upgrade would be a cam at this point. New ones aren't that expensive, and will make more per $ than a stinking y8 head. Then 3" exhaust, 3" downpipe if possible, then 2.5" charge piping. You might even gain from a good fmic like precision, depending on your IAT's. The manifold may be an issue, but they are more expensive than the other options, and some people make good power with a log.

 

Since when do they flow like ----? Please show me ; i'm no fan of any thing y but the main thing thats sucks on them is the oil pump.

 

i don't have flow sheets in front of me, but they suck. if you want more confirmation call larry at endyn.