Originally Posted by 2000SilverBullet
You recently installed a 2.2" pulley. I know you have the series 1 engine and the pulley sizes are different than the series 2 like mine but I think you stepped down in size more than one notch. (pulley boys lists Series 1 sizes of 3.0" all the way down to 2.2")
What was the original size of your pulley?
What made you decide to go with that size first?
I'm trying to decide on how small a pulley size I can go to. Pulley boys list two sizes for the Series 2, 3.25" and 3.0". They don't even list a 3.4".
My engine runs cool and I use an octane booster along with 94 octane fuel so I'm not sure I should be concerned about knock retard.
You have the Jet chip which must help.
Do you think I might need a custom computer burn before I should attempt a switch to 3.25"?
Series 1 will fool you. The 92/93 is 2.5" stock, and the 94/95 is 2.8" stock. The neat thing about this is that the 94/95 uses the stock 92/93 pulley diameter for performance. The M62'* are slightly different, as is the TB diameter. Hence the difference. Some pulley manufactureres used to offer a 2.0" for the early years, but that'* really self-defeating as far as heat is concerned, unless you run an intercooler. But nobody offers a series 1 intercooler. I'm really happy with the 2.2. If you figure out the ratio for the 2.5 to 2.2 change, I'm really happy with it. Not sure on what it did to mileage, cuz I can't keep my damn foot out of it long enough to see!
Pulley Boys used to offer a 3.6 and a 3.4. Not sure what happened. It may be based on what stock he has on hand. Email Brian and ask what'* up! 3.8 is stock for a Series 2 M90.
As far as custom burns are concerned, you still have a Jet option. I'd look at that before a custom burn. If you do burn, wait until you've done EVERYTHING you're gonna do. Get it all if you're gonna drop the cash on it.