Running 20% OD...

89XR7TD

SCCoA Member
MPX,Fmic,60# injectors, tuning chip from Dave, headers into true 2.5 duals...auto car, is it possible to run race gas and be ok using 20% or do I need to add meth kit?
 
Thanks for the replies!!! Hoping to go faster this year Michael :)

Should be able to get into the 13's next time at the track lol
 
I've got a 10% sc pulley + 10% JS pulley on the Teal with an S port, but the engine's been rebuilt and heads worked. Do you have a A\F wideband guage to keep an eye on things?
 
I threw a couple gallons of 112 in the tank before I had my meth kit, now I only run pump gas and that, well did... your car tuned? what kind of intake temps do you have also?
 
I've wondered if the power loss from spinning the blower at 20% would negate the extra boost. I'm running 15% overdrive right now.
 
I've wondered if the power loss from spinning the blower at 20% would negate the extra boost. I'm running 15% overdrive right now.

If the budget allows consider coated rotors from MP vs adding OD.
More boost without needing to up the % of OD. Not an inexpensive mod but subtract the cost of buying the new pulleys and belts you may need.
Runs cooler and will not add heat like adding to the OD.
Will not create additional belt slip.
Coated roters are efficient in all RPM ranges.
Free HP no additional parasitic loss on the motor.
 
20% od? That would be great!

I have a question: what amount of overdrive would you guys recommend running on an early model engine with a late model M90, 36 lb injectors, true dual exhaust and tuned for that setup? You guys are using lots of overdrive, but have MP blowers and whatnot.
 
20% od? That would be great!

I have a question: what amount of overdrive would you guys recommend running on an early model engine with a late model M90, 36 lb injectors, true dual exhaust and tuned for that setup? You guys are using lots of overdrive, but have MP blowers and whatnot.

5% would probably be good to start at....
 
10% would be too risky, i'd imagine? I have heavy duty tensioner springs, so i'd think that belt slip would be minimized.

Generally, with the exhaust opened up & 36# injectors, I'd think 10% would be manageable.

I run a few other mods, but... 10% on my '90 Anny. 5% on the SC pulley and 5% on the jackshaft pulley - one pulley smaller and one larger, so the stock belt works out...I also run a larger top idler, tho, just to be sure. 14# boost on a cool day.
 
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