Sneaking up on more timing without a knock sensor

[CTX-SLPR]

Howdy,

I'm beginning to start to work on the EFI tune of the Riviera and since I'm using a different chamber design than the one the original tune was made for, I need to add timing. I don't know if the knock sensor is working but to be on the safe side how do you start sneaking up on timing without one?

Thanks,

[CDMBill]

Are you convinced the new chamber wants more timing? I ask as with my new motor I have the same head with slightly revised CNC ports and chamber which were supposed to be more efficient. I think they are as best tiing on the engine dyno was 28* total vs. 32* on the old set-up we made almost identical power with 26* but had to add a ramp form 6000-7500 when we went to lower octane umleaded.

We've never had the beenifit of a knock sensor so we look for wierd rich AFR readings which you'll get if starts to detonate as well as carefully monitiing the plugs. What is your testing situation, dyno, chassis dyno, track, street? And what diagnostictools do you have at hand. it wasn't long ago that all we had was a timing light, jets, plug reading light, cut off tool and ET/MPH slips.

there are solid techniques for each.

[Bamfster]

it wasn't long ago that all we had was a timing light, jets, plug reading light, cut off tool and ET/MPH slips.

there are solid techniques for each.

Some of us still only have this stuff too ....

[CTX-SLPR]

By different head I mean totally different design heads, not a CNC porting of the same basic design. I'm running 8445 heads off of an 86 3.8L but the EFI is setup for a 2000 3800 Series II engine which had quite a bit more modern chambers. I don't have a strip to run it at so testing it that way is out. I pretty much have to test it on the street to get it even close before I'd take the time to drive up to Bandemere for a test and tune. I've got a scanner with data logging and wideband plus your basic compliment of compression tester, vacuum gauge, and fuel pressure gauge.