Quote Originally Posted by ProECU View Post
we knew what he meant....move on!

Adrian, I dont think cam gears are gonna fix those 2 dips in the curve.
There is something else goin on there, it has to be igntion timing.

What did you do to timing in that area to test if that was the issue?
Ever consider "retarding" timing... you'd be suprised.
I know what you're saying,
FWIW, we tried both iginition retard & advance...
Also tried humps & dips in the timing at the problem area's with no great result though this did result in smoother power delivery than when the timing curve had a linear advance to peak.
The final curve ended up with a few small humps / dips.
Not pretty, but there wasn't much else that could be done.

Regarding mixtures,
Tried as lean as 13.5:1 & as rich as 11.5:1
FWIW, it liked it best at 12.3~12.4:1 WOT

IMO, there's other issues with that engine,
It's likley the cams are retarded & causing the lack of mid range & high peak.
This could be from material removed during head service & possible use of thinner head gasket.
No adjustable pulleys were available so it's only guess work.
Further to that, there may be an issue with the head on this motor.
In the past, we've had engines built elsewhere, come in to be tuned that have had a similar output charateristic.
When nothing worked to solve it including cam pulleys & the problem turned out to be the valve job in the head itself.
In any case, there's no fixing this one for now as I'm pretty sure that engine is no longer in the car... (Not sure, you'd have to ask Yonas)
Cheers

Adrian