Has anyone went from the stock 2.45 first gear to the 2.28 first gear ?? what was the results ?? will it slow the car down ?? i know it will in the sixty but how much on the 1/4 et ????

Depends on a lot of variables. Usually more SLR will make the car quicker in 60 to a point, as long as it doesn't spin and the suspension is optimized. Smaller drop at the gear change will help a smallerpeakier engine combo. SLR can be be too much or not enough and make the car a turd. When it's right, it makes the car so much better. Ive gone as quick with a 1.98 as I did with a 2.45, but the suspension was set up differently as well. And it would do that everytime - not hook 3 times and turn the tire the 4th. With a 1.76 it was a turd.

MPH shouldn't be effected unless this is 1/8 mile and the combo is way out of whack.

Your 1/8th mile will be off some but your ET will be very close to the same.

I've tried this on my SB 904. I was standing the car up with the 2.45 so I tried to calm it down by switching to a 2.28. The car slowed about .08 in the 1/8. This was about 4500' DA it might have been less in better air. I finally changed back to the 2.45.

What rear gear? You could drop from 4.56 to 4.30 and lose nearly the same starting line ratio 4.56x2.28=10.4 SLR, 4.30x2.45 10.5 SLR. It'll lose a litle finish line RPM, no big deal. Way less money. Plus its a good test.
Doug

One of my customers went to the 2.28 - car was way more manageable off the line and lost a tenth in the quarter.


Making too much lower though - took out the sun gear twice. Had enough - has a glide in it now.

This is an 8.60 car by the way, making north of 1K HP.

honestly its all a matter of trial and error, But here are some things i have learned:

More power needs less SLR
More rear gear and less first gear helps converter stay tighter at top, less slippage
The more SLR you can hook, the quicker ETs

We used a 2.28 in the GTX and it worked well. However, BIg cubes, n20 and 16 x33 tires. Car ran 7.30s at over 190. Short times were off the chain. Car only ran a 3.90 gear. I think it actually calmed the car down and we even considered a 2.08 gear that Rick Allison was working on. Not sure if he ever did that or not. Very specific combination and GREAT chassis.
Todd

A&A makes a straight cut 2.10 set now. Going to try it with a Procharged Hemi. As Tony said a lot of power is needed to pull it.

Had a 2.28 first in my sons savoy. 2600 lbs with driver, 4.56,572 single 4, 1.18 60 ft leaving off footbrake at 3000. Broke wheelie bar at 2 day race. Ran Sunday leaving in second gear. Car ran 5.30s leaving in first and 5.50s leaving in second at same mph

I have a 2.28 low gear in my car with 3.73's, 29in tire. 3500lbs, 528ci on spray. Knocking a little out of the SLR definitely helps on a greasy surface. Ideally, I think the car would be better off with a 2.10 low and 4.10's. It's not happy in high gear as mentioned above.

dvw i dont want to kill it all over just the hit . i had a big motor in the car years ago when i bought the trans because the car would spin a little at the hit. but never put it in now the car dead hooks with the lower first gear. but this trans is bran new and dont really have a use for it. was thinking about putting it in the car just to use it

Rear gear and the resulting starting line ratio change doesn't affect stuff as bad as you think. My past race car went from a 4.56 to 4.10. Didn't slow it a bit. Just made the same swap with a buddys Eddy headed 10-1 440. 4.56 to 4.10. Didn't slow it down at all.
Doug

I had similar results going from 4.10 with a 2.45 low gear to 3.73's with 2.28 low gear running NA. Virtually the same ET and 60ft.