Help Needed Bad

[boosted84]

well finished doin the head gasket did both sides car runs better feels like ive got a better throttle response only problem is the car knocks at ten #s of boost when its hot and is ok to 15 when its cool my upgrades are as below and i checked the fuel pressure it is at 45# line off it also rises with the boost does any one know whats the problem with this setup before it was running 18 -19 #s of boost on 94 with no knock now its knocking all help needed and appreciated i also did a search but is not workin thanks



Anthony

 

[buickpower]

How is your radiator condition, and is all the air out of your cooling system? If you have a water temp gauge, i'd use that to monitor it. Sounds like excessive heat. also, have you always run fuel pressure that high?

 

[boosted84]

i turned up the pressure to try to cure knock but no change how else can i bleed the cooling system ive run it for a while with no rad cap it went down a few times now its full no change i have a temp guage and it doesnt go higher than 170 it used to be at 160 maybe because i had water wetter in there but still have knock i even went down a heat in plugs and nothing would the steam out the exhaust when u blow a head gasket kill the o2 sens maybe

 

[Jerryl]

well finished doin the head gasket did both sides car runs better feels like ive got a better throttle response only problem is the car knocks at ten #s of boost when its hot and is ok to 15 when its cool my upgrades are as below and i checked the fuel pressure it is at 45# line off it also rises with the boost does any one know whats the problem with this setup before it was running 18 -19 #s of boost on 94 with no knock now its knocking ......

What was the old HG on the motor and what are you using now?

 

[boosted84]

old ones were the felpro and the new ones are steel shim i understand about the thicknesses but everyone running these cant be running only ten #s safely and its not like my car is stock so something has to be going on u know what i mean thanks for the replies

 

[Jerryl]

old ones were the felpro and the new ones are steel shim i understand about the thicknesses but everyone running these cant be running only ten #s safely and its not like my car is stock so something has to be going on u know what i mean thanks for the replies

Understand.
While your car is modified, I belief most run around 7 - 10 PSI Max with a stock or slightly modified HA. You just got spoiled and did not know it. (Joke )

If you were able to run 18-19 without knock on 94 before on your listed mods, I am sure you would agree that your combo is special enough (No wisecrack intended) to allow that.

Again, I say unto thee, I am no expert but merely thinking out loud ……
What about the ground cables? Are you SURE they are ok?
False knock?
Maybe a combination of gas quality and other small factors result in 8 PSI boost reduction?

Here are a few assumptions (We know what that does)
The assumptions on gasket thickness and CR are not accurate but close enough for a quick analysis.

Using the stock HA HG vs. the IC HG will raise your calculated static compression 0.5 point.

- Intercooled HG (0.060, 7.5CR) – At 18 PSI boost (assuming you are at seal level) will result in static compression of 16.7
- Stock HA HG (0.018, 8.0 CR) – At 18 PSI boost (assuming you are at seal level) will result in static compression of 17.8
This does not seem to make enough difference to lower boost around 45%. Agree?

If you only changed the HG, you may have intake leaks resulting in
1. Oil suction and depositing it in the intake port or combustion chamber in “no boost situations”
2. And/or blowing the oil vapors somehow into the engine trough a defective PCV, or EGR at low load/rpm levels

Two things are for sure. This is FRUSTRARING as HECK and the “rest of us” would LOVE to know your previous combo set-up to allow 18 PSI on 94.
Heck we'll take 15 PSI! (Can I hear an AMEN?)

 

[boosted84]

thanks jerryl well i took the car to dynotech and the set it up to run 17 #s no knock on 93 so when i started using 94 i turned it up one # (with fingers crossed lol ) and it didnt knock then i got brave enough /or stupid enough to try 1 more # and it was fine but knocked in 4th 2 degrees at about 18 #s so i turbed up the fp a few #s and it didnt knock at all except on a real hot summer day maybe could have fixed it with a little more fuel but hg blew due to the lack of retorqueing them but the good news is got a fresh tank of gas today and back to normal its nice the car feels a tiny bit more responsive to the thorttle one more small ? with a 212 206 cam what would a good idle rpm be anything lower than 800 it bogs under 900 its rough and at 1000 or a little less its perfect but seems a bit high to me and im my opinion high rpm idle and high gas prices dont mix well lol my iac is from an 87 maybe this is the problem
thanks for the help Anthony

 

[Jerryl]

............ with a 212 206 cam what would a good idle rpm be anything lower than 800 it bogs under 900 its rough and at 1000 or a little less its perfect but seems a bit high to me and im my opinion high rpm idle and high gas prices dont mix well lol my iac is from an 87 maybe this is the problem

I think the LS on the cam is 110? Not sure about the other specs (open/ close etc). Better have the experts chime in as I have no experience with this.

IAC is different on an 87 (not sure if it is in the connector only) and not sure what your combo is as far as this set-up.

What I will say is that your combo may idle differently than others, so in essence, whatever works for your car but it may never be silky smooth with a bigger cam.