Gears & Axles - Does a 9" take more horsepower than a stock 10 bolt?

I just installed a MWC Fab9 with 3:89 gears. I took it out to the track today and didnt do as well as I expected. All I changed was the rear end and suspension, I didnt touch the motor. I did put some taller tires on though. Anyways the car just dont seem to have the power it did before, which got me thinking. Does the 9" take more hp to turn than a 10 bolt? I would imagine the taller tires take more hp to turn those as well.

yes it does

Only by about 1000%

really? like a pretty good amount? I'm only asking cause I put in a MWC Fab9(3:89 gear) with a tq arm, lca's, and a phb. But instead of improving my time, my times went up. Now granted it was record temp, 2600 DA, and a 24mph headwind so everybody was off by about 3-4 tenths. I just seemed to be off a little bit more than most so I was thinking it was from the extra horsepower the 9" and the taller 28" tires take.

taller tire is hurting you, should of stepped it up to a 4.11

Most people who install a nine inch do not see their cars slow down, usually it is the other way around. I'd say it was a combination of the record temp, 2600 DA, 24mph headwind and the 28.0 taller tires. Bob

Yeah I didnt think the taller tires would make that bad of a difference but I could tell at the track and everybody else is saying the same thing when it comes to the tires. The reason I didnt go with a shorter gear is because I am going to be spraying the car and if I go with that short of a gear it will cause the car to shift into 4th before the traps. 3:89s with the 28s keep me at the top of 3rd. I think I'm going to use my 26" tires for all motor runs though from now on.

My Stock LS1 cam hits the rev limit with my new 389 gears... I have to put it in 4th gear right before the traps. I think it was about a 25.5" tire.

My Stock LS1 cam hits the rev limit with my new 389 gears... I have to put it in 4th gear right before the traps. I think it was about a 25.5" tire.

Yeah I can see that. I have shift points right at 6600rpm, plus my converter has shift extensions. I wouldnt rap the stock valve train out to high, thats how I bent a push rod.

I lost no MPH going to a 9in and improved 60ft...so technically I gained on both. You just had a perfect storm of variables.

Yeah I can see that. I have shift points right at 6600rpm, plus my converter has shift extensions. I wouldnt rap the stock valve train out to high, thats how I bent a push rod.

Yes Sir. Had my fun at the track and do not want to push it.