Hi everyone.

I have an B16B integra that I sent an well renown tuners shop here in Baltimore MD to have a turbo kit installed and tuned. (Absolute Pro-Formance)

So my problem basically is that the tuner states that when the car is being dyno'd it looses power under VTEC.

The turbo installer/dyno profession states that he went through and examined the following components on the car posted and the car still does not pull during VTEC.
============================

-Fuel pump & install kit
-S300 & ECU
-We have verified all VTEC pins lock
-Tested oil pressure
-Cleaned and checked VTEC solenoid
-Compression tested motor
-Changed distributors
-Changed spark plugs
-Verified voltage at fuel pump
-Verified voltage for VTEC

The only thing left is fuel filter and then we are out of things to check and try
==============================
Anyone ever experience this or have any Idea as to what could be going on with the engine or why its loses power under VTEC?

 

Quick update that I received from my tuner.

He stated the following:

I got to thinking and checking since I needed to walk away from it for a bit. The spark plugs don't show any signs of being to rich and the wideband shows it's in the 10's under boost. Either the wideband is bad and that is our problem, fuel filter is clogged or the injectors are no good. Easiest fix is to toss the old injectors in and do a pull with the piping unhooked and see if the power comes back up.

Anyone else have any idea as to what else we can check?

 

What cams? What rpm is the crossover? What's your exhaust setup? Do you have a flex pipe in the exhaust?

 

Cams? Exhaust Manifold? turbo?

 

Cams are the oem Ek9 Civic type R

​​​​​​Rpm cross over is around 5k

Exhaust is a greddy evo2 2.5" with an integra type r cat converter

I do not have a flex pipe in the exhaust that I know of

And I also have a thicker headgasket that the tuner installed last month which brought it's compression ratio from 10:8.1 to 10:2.1

 

What exhaust manifold and turbo combination?

If it's a cast/log manifold, it's gonna' need VTEC real high.

 

It's a cast/log manifold with a t3t4 57 trim .63 paired.

550cc injectors as well
255lph fuel pump

 

Sounds like vtec engagement RPM is too low. Just a guess.

A good tuner should know how to tune vtec cutover, as well as give it the timing it needs.

I think time would be better spent looking at the tune than trying to track down a mechanical issue that may not exist. As long as it is maintaining those AFR's in vtec then it is not a fueling problem.

 

i would assume the valve overlap is an issue. turbo cams are conservative with overlap otherwise the incomming air charge leaves through the exhaust valves. i believe that NA aggressive cams have a lot of valve overlap. you may want to check cam specs of turbo vs. nonturbo cams from various cam manufacturers.

good luck.

 

Bigger injectors wouldn't be a bad idea.

As stated, log type manifolds require higher VTEC engagement points. Try 6K+.

Also get a flex section in that exhaust before you start ripping studs out of the head and have nuts backing out on you left and right, or even worse a crack on the manifold.. The added weight and vibration on the manifold/turbo will cause that and you'll be left with exhaust leaks.

 

I'd love to see a pic of this dyno chart showing the problem. simply saying "it loses 50hp" is entirely too vague.
I too think it's actually just a problem with the tune, not a problem with any parts.

 

a b16b is going to be 6,000 rpm for vtec cross over. 5k is way to low. ( I had a b16b)

post a power graph

 

This

 

I tend to agree with this also, and so what I'll do is migrate this over to the Engine Management & Tuning Forum, where Reireii may get some better feedback.