Problems With Knock In R33

[85URE]

hey all.

well when i bought the car it was set to run 23psi all the time, as i no not too much about turbo cars or tunning them i took it in to get tuned cause once boost comes on a small light would flash on the dash...

once they had it on the dyno they got to 275rwkw but had to back off cause they said the light coming on was the knock sensor, so they would start tunning down the boost till they found a happy running level. they got down to about 13psi with 225 rwkw before they were happy with the curve's and running of the engine.

the next step now is to do what i have to (with in reason) to get that power back.... and if i can get to 300rwkw or over

so with them then looking at the setup i have....

T60-1 with aftermarket wheels

gready external gate

gready duel stage boost controller

trust front mount

HKS senquental BOV

larger injectors

Nismo fuel pump

Apexi Power fc

4" exhaust

with the injectors running at the above figures only on about 52% duty cycle they said my next step would be to fit a 2mm head gasket to allow me to run more boost without engine knock being a problem and my kw figures would go up alot

this is basicly all i have been told, $2000 for 2mm head gasket fitted and tunned

does all the above sound like the way i should be going??

can anyone recomend any other places to get this sort of work done around Brisbane??

any advice or opinions or examples of what you'v done are welcome

thanks guys

Mark

[Sydneykid]

hey all.

well when i bought the car it was set to run 23psi all the time, as i no not too much about turbo cars or tunning them i took it in to get tuned cause once boost comes on a small light would flash on the dash...

once they had it on the dyno they got to 275rwkw but had to back off cause they said the light coming on was the knock sensor, so they would start tunning down the boost till they found a happy running level. they got down to about 13psi with 225 rwkw before they were happy with the curve's and running of the engine.

the next step now is to do what i have to (with in reason) to get that power back.... and if i can get to 300rwkw or over 

so with them then looking at the setup i have....

T60-1 with aftermarket wheels 

gready external gate

gready duel stage boost controller

trust front mount

HKS senquental BOV

larger injectors 

Nismo fuel pump

Apexi Power fc

4" exhaust

with the injectors running at the above figures only on about 52% duty cycle they said my next step would be to fit a 2mm head gasket to allow me to run more boost without engine knock being a problem and my kw figures would go up alot 

this is basicly all i have been told, $2000 for 2mm head gasket fitted and tunned

does all the above sound like the way i should be going??

can anyone recomend any other places to get this sort of work done around Brisbane??

any advice or opinions or examples of what you'v done are welcome

thanks guys

Mark

<{POST_SNAPBACK}>

Hi Mark, lots of things cause knock, so there are lots of cures.

1. Low octane fuel, use higher octane

2. Too much ignition advance, retard the ignition

3. Too lean A/F ratios, richen them up

4. Too high inlet air temps, lower boost, better intercooler

5. Too much boost, turn down the boost

6. Too high a compression ratio, lower the compression ratio

I am surprised that they went straight to #5 and then suggested #6 as the solution.

Personally I would have started with, #1 what fuel are you using? Should be BP Ultimate 98 in Brisbane, as BP has a refinery at Bulwer Island. Then I would have retarded the ignition timing #2 in the areas where knock was too high, and left it alone or advanced it in areas where it could handle more advance. As that is better for response. At the same time I would have looked at the A/F ratios #3 and made sure that they weren't too lean in the areas where knock was too high. Maybe then richened them up slightly. Then I would have had a look at the inlet air temps, and if they were too high had a look to see what was causing that.

Every engine is different, but I would be surprised if you couldn't get 300 rwkw with a T60-1, the relevant compressor map follows;

As you can see 50 lbs of airflow per minute (easily enough for 300 rwkw) is availalbe at 1.2 bar (18 psi). Boost at 1.6 bar (23 psi) is way outside the efficiency islands, and is the primary cause of too high inlet air temps, ie; #4.

I noted on your list of mods that camshafts are not included. Personally I wouldn't be spending my money on a thick head gasket and introducing other problems, I would put in a set of Tomei 256 degree Poncams instead. That will lower the dynamic compression ratio and provide more airflow capacity at lower boost. It's a win win scenario.

Hope that was of some help

cheers

PS; I wouldn't be going much over 300 rwkw with standard internals.

Edited August 26, 2005 by Sydneykid

[paulr33]

here here, also you have complete engine management yet they've just said change the gasket, there would be a dozen odd changes you could make with the powerfc's management system to correct and workaround the issue as sydneykid has said.

whats the point of engine management if you dont mange it?

[85URE]

thanks guys,

points taken.....

i always use bp ultimate fuel....

i take it there is no way at noing weather it has different cam's already??

all the "good gear" was on the car wen i bought it so i don't no how deap

they went, i no pistons and rods are stock thats why im just trying to get

to 300rwkw don't drive in boost that much anyway, just cruise.....

but like to no its there wen i need it lol

wen they had it on the dyno, they played with "everything" for about

3 and a half hours, every now and then coming in and telling me somthing

about timming, or ignition so im thinking they would have gorn right through

ur list..... and thats why they ended up turning down the boost and recomended

i go with the thicker head gasket....??

they did say down the track for me to go with a different intake plenum

so i wasn't piping across the hot engine (for intake temp's) like u say.

"sydney kid"

are you saying that if it does have standard cam's and i had fitted a set of Tomei 256 degree Poncams instead that would decrease my compression a little and make up for other things to give me that gain insted of just going with the head gasket??

"paulr33"

true true, like i said though, id hope that if they took that long that they were useing the managesystem to their advantage.... if it wasn't so expencive (dyno time) maybe i might be better off taking the car else where for a second opinion..??

but THANKS "sydney kid" & "paulr33"

Mark