i just got a moroso advance spring and weight kit and now i have to decide what springs to use. i have the vacuum advance set stock, (non-adjustable) and my initial advance is 12*. heres what the instructions say about springs-

RPMS 1500 2000 2500 3000 3500 4000 4500 5000 5500

Light 6* 8* 14* 16* 18* 20* 22* 24* 24*

Med. - 2* 4* 8* 10* 12* 14* 14* 16*

Heavy - - - - 4* 6* 8* 10* 12*

(continued)

rpms 6000 6500 7000

light 24* 24* 24*

med 18* 18* 22*

heavy 12* 14* 16*


whats best? should i use one light and one med, or is two light springs safe with the stock amount of vaccuum?

 

nobody???

 

The only sure fire way to get a kit like that to work properly is trial and error.

Start with the middle springs and go from there.

If you don't get knock, go lighter (less tension) and drive it again. If you do get knock, go heavier.

Just remember the springs only change the rate of the curve (i.e. how soon total advance comes in). It doesn't add or remove anything from your total timing. Get that set first.

As far as mixing the springs...... if you get some knock, try using one heavier spring on just one of the weights. See what it does and go from there.

 

Every time I've used that particular kit, I ended up with one light and one medium. The motor would run a little better with both light, but then they're so light, they won't return from advance all the way reliably; so the idle was all over the place.

Given that, follow AJ's advice, and play around with them until you get as much advance as you can without pinging. That's usually the optimum setting. If you have access to a chassis dyno, or even a G-tech, you can try tuning for best mph.