Greg Bentley
Well-Known Member
What kind of timing are you running on your small block turbo combos on 93 pump gas? 5-15 psi.
boost/timing
- Thread starter Greg Bentley
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T56MaxTorq
Well-Known Member
The difference between 5 am 15 psi is a lot in terms of timing. I believe most run a locked out distributor and pull 2-3 degrees per lb. of boost.
My slant six is turbocharged, but is not intended to be driven on the street. It is a race=only vehicle, so the ignition timing is not what you'd want in a daily driver.
I have done a LOT of reading in the last 5 years about the various facets of forced induction as it relates to slant sixes and almost to a man, the recomendations have been that if you want to stay away from engine damaging detonation, BECAUSE flame fronts in a boosted combustion chamber travel across the top of the piston a whole lot faster than they do in a naturally-aspirated engine, NO MORE than 18 degrees of spark advance should ever be used while an engine is under boost.
So, I bought an electronic Mopar distributor built for a "Lean Burn" equipped slant six, and it has NO mechanical advance mechanism of any kind and NO vacuum advance canister. In essence, the plate is LOCKED, so no advance can come from the distributor. Then, I set the timing on the crank, at 18 degrees, locked the distributor, and forgot it.
No advance beyond the 18 degrees I set, initially.
It is, like I said, a race car; no street time, ever.
But, it starts instantly, has no problem with kickback at startup, and no run-on when I turn it off. I think the boost covers a lot of problems, because it doesn't seem to need an advance curve. Oh, and it runs cool...
That would probably all change, if it were asked to do duty on the street. In fact, I'm sure it would.
But, since it does life a quarter-mile at a time, it seems happy with this setup. No problems, so far...
rayer:
Greg Bentley
Well-Known Member
It was cylinder #5, I found that the wastegate was stuck closed and the boost went to over 15 psi before I could get out of it, timing was on 19-20 degrees.
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