Ignition Timing on Turbo Quad4

Hello,

I'm looking for some help with ignition timing.

Here's the application.

9.5:1 CR Oldsmobile Quad4 (DOHC 2.3L) in a Beretta GTZ. I have added a Garret T3-60 and am running 6-9 PSI of boost with a small intercooler. (starts at 9 and trails off as RPM gets above 6000) I have also added 55 lb/hr injectors to help in that area.

I have the fuel tuned in the 120-170 KPa area to be set at 13.0 AFR on my TEC-II (which a tuner with this motor has told me that 13.25 on this TEC version was best on his NA motor and I also had good results at that setting on my NA motors) I expect that setting to be between 12.5 and 12:1 ACTUAL AFR. (I realize that the stock O2's aren't that accurate)

But I'm running very conservative on timing. The car runs at 28 degrees total when off boost and then I have the timing set at 15 degrees total between 120-170 KPa. So far everything seems ok, but the EGT's will climb to 1600 degrees pre-turbo by 90 MPH (top of 3rd) I'd like to bring those temps down to 1400 or so. I'm thinking that my timing needs to be advanced some more.

So does it sound like I'm on the right track or do what do I need to do to go from here?

Thanks guys!! I know I'm an odd ball. ;^)

Rex Weatherford
92 Beretta GTZ
14.7 @ 96 MPH on NA motor.

 

[stevieturbo]

an AFR of 13 would be considered quite lean for any positive boost pressure. That would explain the high EGT. I would aim for a minimum of 12.5:1 but would prefer 12:1 or slightly richer, approaching high 11's

 

[buzz41]

I will just blurt out my impressions. Get it wetter. And bump the timing up to where you are nibbling on knock then back off a tad. Both will help get the EGT down. Late timing alone WILL make the EGT high. I think stevieturbo has the mixture numbers dead on.