Many claim that doing the following mods:
- cold air intake
- bigger SMIC
- DP
- MP
- muffler
- remapped ECU

should yield in about 300rwhp and 1/4mile times of mid to high 12's.

I have additionally efini y-pipe. I run 9/7 plugs.
I have a small exhaust leak at the turbo/DP connection. My boost is 12-8-12. Sometimes it falls lower then 8 at transition but then picks back up quickly and holds full boost up to redline and past. I get full boost at 2.5k RPM. I have a 2"1/5 restrictor plate at the DP/MP connection and smaller diameter piping towards the muffler (I'd say about 2" or a bit over).

I netted about 245rwhp (285 at flywheel) at 12psi on a dyno and did 13.4sec @ around 106mph at 13psi.

So I'm looking for suggestions what things to check to determine where I'm loosing aprox. 50-60hp.
I have a plan to do a compression test.
My suspection is bad turbos or a small boost leak, causing turbos to run out of their sweet spot and feeding too hot air.

So if you feel there is something that should be checked please chip in.

Thanks !

 

^

 

I'm tracking down the same problem on my FD....

Have you tried hooking up a second boost gauge to your y-pipe to test out your boost-leak theory? I recently did this and saw about 1 to 1.5psi difference at WOT. I consider this a little on the high-side, but still normal. Try it and see what you get. I tapped in where the y-pipe connects to the pressure chamber check valve (before).

 

One reason is that your exhaust piping is too small.

 

Uh, that doesn't give you a clue?


-Ted

 

Anything with the name "restrictor" is bad in my opinion! hehe

 

I will remove the restrictor plate... no need for it anyway...

Did you T into that line for 2nd boost gauge ?

I think 1-1.5psi pressure drop is normal for smaller SMICs.

Strange thing is that I have strong tq numbers - 260lb/ft at 5200RPM at 12psi...

 

Additionally... I will put in the Pettit ECU and try to measure the difference on my GTech.

 

Yeah, just T into that line. This method isn't too accurate when using mechanical gauges, but it'll give you an idea if something is wrong. I plan to use two sensors to get a more accurate measurement.

My torque is also strong up to 5700, but falls off rapidly thereafter and results in low peak-HP numbers. Most FDs hold torque out to 6000-6500RPM, which gives them much higher numbers (HP = tq*RPM/5252). The problem is obviously a flow issue, but since I have DP/MP/CB, it must be the engine itself (porting?) or the turbos. Still testing...

 

I will be able to perform the test in about 2 weeks (guess I'm the only one around with a boost gauge, lol).

Do you get 3psi of boost when you rev it in neutral ? I do. I dont think you get that if you have a boost leak.

I will also do the 3" piping all the way back.
I will put in an ignition amp.
I will change the plug wires.

This should eventually release some top end power. But when all this will happen I dont know atm. New exhaust will be about $600, amp + wires + new UIM gaskets another $500-$600.
Not to mention I need new tires

Btw. did you have your injectors cleaned and inspected ? I think mine weren't worked on yet and have about 85k miles on them (on second engine).

There could be something with them also, bad spray pattern or something...