How Much Timing To Run ??

[BMF_Racing]

i have a stock unopened 3.8L with club springs.

60lbs with Maft pro and alky.

I'm going to run it this weekend for the first time since the maft pro and 60's and will have a 110/ 93 octane 50/50 mix in the tank just for a saftey net.

How much timing can i run on a stock turbo/intercooler with 18 to 19 psi??

How much would be a good starting point? I did a street pull yesterday with afr reading 11.2 on the wideband and timing at 18 it felt good but wasn't sure how high everyone runs ??

any help is appreciated,

Brad

 

[BMF_Racing]

ttt anyone ???

 

[TurboDave]

As long as you're holding your boost at 19# and are only concerned with a timing issue, with that fuel mix, you should be good to at least 22°. Possibly a little higher depending on just how good your fuel mix is.

 

[BMF_Racing]

As long as you're holding your boost at 19# and are only concerned with a timing issue, with that fuel mix, you should be good to at least 22°. Possibly a little higher depending on just how good your fuel mix is.

well i said 50/50 mix on the 93 and 110 octane its more like 60% 110 and 40 % 93 and it is 100% alky spraying.

I was going to try for 20 degrees, just was going to watch the scanmaster for knock. Does it have to read zero or is anything less than 2.0 degree of K.R. ok ??

 

[TurboDave]

At the boost levels you're talking about a ° or two probably wont have any detrimental effect, if it's short lived.
Anything over 20# of boost and I wouldn't tolerate much more than a tenth or two of retard. 22° was the stock chip's timing, and you're still way below that!!
If you're spraying alky on top of race gas you should have no worries what-so-ever with knock.

 

[ijames]

That mix will give you about 101-102 octane before the alcohol, and 22-24 deg of timing is pretty typical for a "100 octane" chip, so you should be very safe at 20-22 deg. Personally I like zero kr for the entire pass. I have spent a lot of time tuning with 93 octane and no alky, at the edge of detonation, and my car always slowed down if I got more than about 3-4 deg of retard at any point, or non-zero retard for more than maybe 3 seconds total. That was with 20 deg of timing. With more advance and more boost I wouldn't push that hard - shoot for zero, it's the safest.

 

[BMF_Racing]

At the boost levels you're talking about a ° or two probably wont have any detrimental effect, if it's short lived.
Anything over 20# of boost and I wouldn't tolerate much more than a tenth or two of retard. 22° was the stock chip's timing, and you're still way below that!!
If you're spraying alky on top of race gas you should have no worries what-so-ever with knock.

I just wasn't sure because of the factory intercooler still.

 

[bison]

With 19-20 psi and alky id be willing to bet you could get away with 28 degrees advance and possibly as much as 30. Go up a degree at a time and make sure the water temp in the engine is the same every run. Be sure there is no retard at all. Report back. Fwiw i used to run 22 degrees and 25 psi on top of 9.0-1 compression with 93 and alky without a 110/93 mix. With around 105 octane i easily ran 27 psi and 24 degrees advance with alky.