I just dynoed my car today, is a fully built B18b1. There are 3 graphs blue one is at 14psi the other 2 were at 17 psi my question is i am making the same power up top but as you can see I making a little more in the middle at 17 psi. At 17 psi the afr is 10.6 and with 14psi the ratio is 11.5. How much leaner should I shoot for. 11.5? Btw turbo is gt35 fuel shell 91oct. Any suggestion is welcome.

 

yes 11.5 is a good number some go to 12 all depends on what the set up shows you it likes by how the number increase or decrease

 

what ^he^ said.

it could also be because the motor is starting to choke out a little up top, whether it be due to the intake manifold, cams, exhaust, charge piping, and more

 

Manifold is Victor X, cams are crower stage 2 if not mistaken, turbine housing open .82ar, 2.5 exhaust with 2.5 dp charge pipes are 2.25.

 

The 2.5" DP/exhaust is your restriction

 

if you have a cat installed, that would be my first guess for the restriction.

2.5" shouldn't restrict it all that much at this power level, unless it's crush bent and not true mandrel bent. if it's crush bent, yeah that definitely can be a restriction, because it will only flow through the crushed areas as much as a 2" or 2.25".

2.25" charge pipes are also a little on the small side. I never run anything smaller than 2.5", on anything. typically for charge pipes, I match the TB bore, or go 1/4"-1/2" larger than TB bore. and if you have a victorX manifold, I'm assuming your TB is at least 60mm (2.36"). if your TB is 64mm or larger, you definitely want to go with 2.5" charge pipes [or 2.75"]

 

100% agree.

my old setup



b18b1

(100% stock head)

Block has eagle rods, stock pistons)

On a 60 trim precision, I put down 362whp on 19.5 psi. 3" downpipe and exhaust.


your 2.25" charge pipes are OK at your power level (if its crush bent, please throw that **** out and buy a 2.5" kit) I think your manifold is a bit large for your needs, but I'm not entirely sure since I have zero experience with a victor X, I just know its a large manifold.

 

I check yesterday the exhaust and found the issue, a 90° crush bent elbow measured 2.12 OD, and the elbow that goes to the turbine housing is crush bented to a 2.38OD. Maybe I need a new manifold the space I got to work with is a little in the thight side dont know if a 3"in downpipe will fit.

 

 

EGTs would have been my first thought. Looks like you sorted that out. But that's a lot of power on an eBay log manifold. That should be the first thing to go. Get one made so you can leave more room for a proper downpipe as well.

 

I am in searching manifolds as we speak, I am over boosting bad with this one, the 35r is to much for the manifold and the 38mm WG. I am inclining for the go-autoworks ram horn with the 44mm v band WG, but I am not sure if the 44mm will cut it. Also made the DP and the exhaust, 3in mandrel bent, much better response.

 

44mm will be fine for a GT35R. It's a matter of tune and boost control at this point. You'll need to retune this setup anyway with the new equipment

 

The problem was the log manifold, I swap it for a BWR ramhorn picked up a tial 44mm wastegate and at the same psi picked up around 45whp just adding some fuel compesating for the new manifold

 

Nice gains!