Dyno loss with 4.10's?
Burning Brakes
Joined: Jan 2008
Posts: 905
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From: BURTON MI
Actually it is kind of a big deal. Well maybe not a big deal, but it is of some importance. There are still those who reject the idea of a "perceived" power loss on the dyno with higher gears. Perhaps if we can break down the science of it we can get a better explanation of how and why it happens and convince the sceptics. Or rebutt our own theories if that is the case.
I know this is called the "Tech" section but most of the topics have little to no informative mechanical content. I for one love to keep learning and I don't believe this thread has become "silly" in any way.
I know this is called the "Tech" section but most of the topics have little to no informative mechanical content. I for one love to keep learning and I don't believe this thread has become "silly" in any way.
Last edited by BOB EAGAN; Sep 28, 2008 at 10:33 AM.
Le Mans Master
Joined: Jul 2005
Posts: 5,328
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You are correct in this being the Tech section and we do appreciate everyones opinions. I and some of the other members were not as receptive to scientific points of view the way they are being presented. This is the tech section of the Corvette Forum not the MIT engineering newsletter. Again, I do appreciate all the comments here and hope everyone tries to keep them friendly. Have a nice day.
Moderator
Joined: Dec 2002
Posts: 40,901
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From: Lakewood Ranch, FL
Most threads here are silly in one form or another, yet we continue to come here. If you want to keep your comments "simply", that's your choice and I would never say anything to you...rock on! On the other hand, I've gotten plenty of people make posts or send PMs thanking me for a technical explanation and will continue to post them when I have the info. I've also been corrected here at times...it's a place to have discussion and share ideas. If I thought I was the smartest guy here, I'd just dominate every single thread with my superior knowledge yet I don't post that often. This is America, if you and other members (rather big of you to speak for others) don't want to read scientific points of view, that doesn't mean those points of view shouldn't be here. MIT engineering newsletter...that's funny, just can't stay away from hyperbole can you. You're the only one I see making this thread silly. There are quite a few engineers here that post technical info, just put us on your "ignore" list and we'll all be happier.
Thread Starter
Tech Contributor
Joined: Mar 2003
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From: Colorado Springs, CO
St. Jude Donor '08-'09-'10-'11
1st Gear
Joined: Oct 2008
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I was googleing "dyno loss 3.55 4.10 gears" when this thread came up.
Thought that since I had some data I'd share it. My car is a 2008 Mustang GT. Had a dynojet dyno done with the stock 3.55 gears: 277HP 297TQ. Changed the gears to 4.10 and put underdrive pulleys on: 274HP 290TQ. The numbers are SAE corrected. Others have seen 6-8 HP increase from the pulleys so if I factor that in the loss would be right around 10HP. Same dyno, almost the same weather conditions, 1 month apart.
BTW nice web page.
Thought that since I had some data I'd share it. My car is a 2008 Mustang GT. Had a dynojet dyno done with the stock 3.55 gears: 277HP 297TQ. Changed the gears to 4.10 and put underdrive pulleys on: 274HP 290TQ. The numbers are SAE corrected. Others have seen 6-8 HP increase from the pulleys so if I factor that in the loss would be right around 10HP. Same dyno, almost the same weather conditions, 1 month apart.
BTW nice web page.
Team Owner
Joined: Mar 2005
Posts: 20,933
Likes: 905
From: salem OR
I have a 08 ls3 and made 423 with the 3.42's.With kook's headers. Then installed 3.90 gears and a A&A kit. Which make an average of 175 rwhp. On stock ls-2's and 3's. But only dyno's 515 on the same Dyno. But 3-4 others made 525
-597 with the same mods same kit on LS-2's. Your dyno loss is the
percent difference between the Gear ratio's applied to the RWHP
reading so it is less with less power,more with more power. In my case it's about 65 hp.
Call BS if you want but there's NO FRIGGN WAY I gained less than 100
rwhp with the A&A kit thats making a full 8 pounds plus boost!and tuned properly.
I can assure you that I am making every bit of power the ls-2
dyno'd or more. Dyno jets have a gear selection on the screen. Mustangs do not and show more loss because the lower gears make less RPM and the Mustang sees that as less power.
-597 with the same mods same kit on LS-2's. Your dyno loss is the
percent difference between the Gear ratio's applied to the RWHP
reading so it is less with less power,more with more power. In my case it's about 65 hp.
Call BS if you want but there's NO FRIGGN WAY I gained less than 100
rwhp with the A&A kit thats making a full 8 pounds plus boost!and tuned properly.
I can assure you that I am making every bit of power the ls-2
dyno'd or more. Dyno jets have a gear selection on the screen. Mustangs do not and show more loss because the lower gears make less RPM and the Mustang sees that as less power.
