AX_Bucky

I havn't got a scooby so be a bit gentle with me please...

I have just done a turbo conversion on my AX and I have a little pinking problem.

What inlet temp is safe to run at???

It's not the fuel but I am running standard ignition timing at the moment, thing is the supercharger saxo's run standard timing and they get no pinking..

Just got me by the ***** thats all..

I have a dastek to go on in the next month or so, but wanted to get some more idea's before it gets installed..

Dave

dhorwich

Did you lower the compression ratio.... as standard normally aspirated engines have high compression ratios... compared to turbos..... you can lower the compression ratio by a thicker head gasket i think...

Dan

AX_Bucky

Done that mate, 2 thick head gaskets.... sounds dodgy I know but it works.. Been tested by GMC to 22psi..

dhorwich

What about....

Head gasket leak..?
Weak mixture..?
Intake air temps..?
Carbon build up on engine (pistons, head)..?

Have you tried retarding the timing....

What about the grade of spark plug your using... they have different heat ranges.. this can have a big effect on pinking....

Also what about the coolant....try diluting it down.... if you have it at 50/50 conc this has an effect on the RON octane requirment of your engine.... you only need 50/50 in winter, and it is actually the water in the coolant that removes the heat from the engine.... all the coolant does is raise the boiling point of the water and stop its from giving off steam..

Dan

Dan

AX_Bucky

Head gasket leak.... I have just changed the gaskets so I doubt that..

Weak mixture.... I have an air/fuel ratio meter and it says it's fine

Air intake temps are around 10deg C (so my SPA gauge says)

When I took the head off to do the head gasket there was no carbon build up at all.

The timing is done by the ecu, I know it is mapped for an N/A engine, but it has a knock sensor so should retard the timing (not that much I know)

Plugs I changed to RS Turbo ones...


Coolent I havn't thought about, did think it would make any difference.
The mix is about 30/70water.

Me personally think it's the ignition timing, but I have got my cam timing slightly advanced by about 5degs. Will this make a big difference????

dhorwich

If i were you i would probably try retarding the timing until you dont get pinking....

AX_Bucky

OK Cheers mate I suspected it was that but just wanted to get other peoples opinions...

It could be the MF2 I'm running cos it's a bitch to set-up...

ustolemyname??stevieturbo

iTrader: (1)

I highly doubt boosted air temps are around 10 degC. Are you reading ambient air or boosted air temps?? What fuel/ign setup are you running? Has your cam timing ( and also ignition )been changed by the addition of the second head gasket?? How much boost are you running, and what is the compression lowered to?

[Edited by ustolemyname??stevieturbo - 4/25/2002 8:32:34 PM]