Lethal Induction 2.0 - 70 Chevelle

[ChevelleNV]

Can you talk a little about the zl1 blower on a big CI engine? I have a 418 and picked one up for cheap. I also have a stock ls2 and ls3 heads. Everything I read says it won't move enough air for the 418.

Hmm, they say not enough air?...



I find that hard to believe since the ZL1/LSA supercharger is a constant displacement supercharger, you want more air then put a bigger pulley ratio to spin the screws faster....

Now on my particular application we are under driving the supercharge for less boost, so i didn't have to buy new pistons to lower the compression ratio.

here's my math, and if any one sees a issue with this math, speak up...

The stock ZL1 376CI makes 9lbs of boost with a 7.8in Crank pulley and 2.95in blower pulley which gives it a 2.6 pulley ratio
Math: 7.8 / 2.95 = 2.644

My 441 is almost 18% bigger than the 376CI ZL1
Math: (441-376) = 65 / 376 = .1728 x 100 = 17.28 = 17.28%

so if I ran the stock ZL1 pulley ratio on my 441 it would make 7.67lbs of boost
Math: 9lbs boost/1.1728 = 7.67lbs

SO I was able to find some pulleys to use that give me a lower pulley ratio so I could under drive the super charger
so with the new calculated boost of 7.67 and a new pulley ratio of 2.183

Math: (7.67/2.6) = (2.95) x 2.183 = 6.43lbs

So depending on how much boost you want to make... we just have to up the pulley size.

so lets run the numbers on your 418....

we already know the 2.6 stock pulley ratio
Your engine is roughly 11% bigger than the 376 ZL1
Math: (418-376) = 42 / 376 = .1117 x 100 = 11.17 = 11.17%

so if you ran the stock ZL1 pulley ratio on your 418 it would make 8.05lbs of boost
Math: 9lbs boost/1.117 = 8.05lbs

so all you have to do know is know how much boost you want to make if 8lbs is not enough and figure out a different set of bigger pulleys