No Torque

[MONEYPIT]

BROUGHT THIS 87 GN THAT NEEDED WORK, AS FAR AS SUSPENISON,FRONT END,SHOCKS,TIRES. WELL ABOVE WORK IS FINALLY COMPELTED AND CAR IS INSP. TOOK IT OUT FOR A WOT PASS. MAN WAS I DISAPPOINTED!!! VERY LITTLE TORQUE, KNOCK GAUGE WAS IN THE RED AFTER BOOST WENT ABOVE TEN, THIS CAR HAS 40# INJ,ADJ FPR,HEADERS, BIG S/S EXHAUST,BOTTOM END HAS LESS THEN 5000 MILES.IT DOES HAVE A EXHAUST LEAK IN THE CROSS OVER PIPE AND BELOW THE TURBO. WOULD THIS AFFECT TORQUE??? OR IS TORQUE DEVELOPED IN THE TOP END, WHICH NEVER HAS BEEN TOUCHED AND MAYBE SHOULD BE REDONE TO FACTORY SPECS
THANKS IN ADVANCE FOR ALL REPLIES

 

[Carolinaturbot6]

MoneyPit, the first thing I think you need to check out is the knock retard. You need to make sure the fuel pressure is rising with the boost. Of course the only way to check that is to mount (tape or whatever) a fuel pressure gauge to the hood/windshield & moniter under load. You do have a good fuel pump correct? Has the fuel filter been changed lately that you know of?

A scan tool of some sort is really needed when trying to tune & trace problems on these cars. It can be frustrating at times. You are looking at an aftermarket boost gauge? The car may be sluggish because the ecm is retarding timing because of the knock, therefore cutting power.

Exhaust leaks will affect the performance. I'm curious, what leak near the turbo are you referring to? Little things on these cars can make alot of difference. Sometimes good, & sometimes bad.

It would be helpful if you would take a few minutes & add a signature with ALL the mods on the car. One thing you can do fairly easy is to add some higher octane & see if that cuts down, or eliminates the knock. That would show us that it is indeed real knock, & not false knock.

 

[GNflyby]

Sorry if this is a stupid question, But what is the differance between real knock and a false knock. Still new to the Darkside.

 

[Carolinaturbot6]

First of all, there's no such thing as a stupid question...well almost.
Real knock (detonation) is when the engine is experiencing too low of an octane, too lean of a fuel mixture, or too hot of a spark at any given time. Carbon buildup will also cause it.

False knock is when the knock sensor hears things such as valvetrain noises (tapping, ect.), rattling idler pullies, and/or loose engine brackets & such. Anything that may be "loose" or broken can cause noises that the knock sensor hears. The knock sensor can't differentiate between what's "real" or "false". If working properly, it will start cutting back the timing to help prevent damage to the engine itself.

I'm sure someone else can add to this. HTH

 

[MONEYPIT]

spring cleaning has been performed on this car as far as the fuel pressure i have it set at 40# at idle i also have fuel gauge that mounts directly to the schader valve with lucas 40# inj .do not know if there is a modify chip to match the inj, and the fuel pump is mounted outside the tank may be the pervious owner did not want to go through the trouble to drop the tank