For you turbo guys running big boost, let me give you some knowledge I learned through the years...
From the mouth of the great John Mahovitz...
"Big boost modular motors are prone to be dangerous when lean. What most people think is lean is very wrong. There is a lot of talk about mid 11's and an a/f ratio over 11.0 is actually very lean on a modular motor making over 22 psi - especially on a turbo car. The a/f ratio with a 25 psi set-up should actually be in the 10.5 range. On my motors and builds, I try to average around 10.0 a/f"
Mark Ive been doing this for 2 years with my car , I have always preached the same thing . Something I learned a long time ago from My Pro Racing Buddies.
Thats why I built the motor 8.7.1 not higher compression like most others.
When running c16 I only had 16* of timing , just would run alot more boost and a/f was typically around 10.80 to 11.20 .
Once we made the switch to E85 the a/f and timing changes alot .
We ran the car same boost 23 and left the timing were it was and b/c of the cooler fuel it was way fat 9.60 a/f . Car ran like ass and didn't make as much power. E85 needs timing and alot of fuel , we started to add timing and the motor responded. Every time we added timing it made more power . We had to stop b/c it started blowing out spark , hence the situation we are dealing with now. Before on c16 with 23 psi's and the HTO's gapped at .026 no problem would pull clean , now E85 same boost same gap alot more timing a/f around 11.6 spark goes out . You can see it puff out the exhaust at 5400 rpm.
We made a pull with the a/f in the 10.80s and it lost 54 hp so we know it has to be a spark issue.
The car is still 100% street ass heavy nothing removed other then a K-member now, so I dont want to start hacking the harness or going to a different ignition type.
If I do that its b/c a bigger motor , turbo and heads and cam are going in the car at that point will be at a different level more RACE then Street.
What fuel system do you have on your car? Having a returnless system no matter how many pumps is a headache when you start getting into bigger power levels.
Mark Ive had the return style fuel hat since it was 1st available . I was on the phone with Fore and Lethal, so much that when Jared got the 1st kits I went to Lethal to pick it up the day after.
yep! Just go to a BS3 now Pete - you know you are heading there anyway...lol
Hahahahahah I know , I know . Just trying to push the envelope a little more with stock heads and cams . Believe me when I go to a 323ci ported heads and cams , Ill upgrade to a Billet 88mmbb then Ill get the BS3.
Everyone has made very good points , but I want to see if I can go a little further with this set up .
Im a Big Fan of BS3 , but for my current set up and level dont want to change yet.
Eric also has good point, but If I were to go that route between all the expenses Id rather go with the BS3. Just not ready to make the jump yet.
