Ok...I have a 5 speed...how much horsepower loss is generally accepted as to being lost from the engine to the rear wheels?
Thanks!
Thanks!
rwhp loss through the drivetrain
- Thread starter 98stangv8
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BurningRubber
10 Year Member
- Dec 6, 2004
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Around 15% of your flywheel horsepower for a 5 speed. That is not exact, but a fairly common figure.
98COBRA281
10 Year Member
i hate when people say a percentage, because its not true at all, so 1000 crank hp, would mean 150hp loss throught the drive train, which is crazy..
manual 30-35hp loss
the guy above was at at 12% loss...I have heard 10-15%....if you are running 1000 hp at the crank...you are going to lose more than a guy running 260 hp at the crank...so it should be more of a %age than a number...
98COBRA281
10 Year Member
why would you lose more hp just because you make more power? theres no difference.......
CobraRed_96_GT
Active Member
Move an oar through water, then move it 5 times the speed through water. Notice a difference? Relate to oil respectively.
It's %
CobraRed_96_GT
Active Member
i usually say 14-15% through a 5 speed or 6 speed, and 18.5-20.5% on a 4R70W depending on build.
People like to say 15%...but that is a generalized statement that doesnt take into effect many variables..such as rotational mass, gearing, car weight and such...but honestly what does it matter? its not so much the power that the engine makes, its the power that is effectively put to the wheels as they push the car forward. but if you really wanna know what kind of loss YOUR particular car has and if you want an ACCURATE number, take the motor out of the car and have it engine dynoed, then put it back and do a wheel dyno....but even that isnt that accurate because different dynoes will give you different numbers...so...yea.
Because the transmission causes an operating loss of roughly 10-15% due to heat & friction. Its not like it arbitrarily saps 30hp no matter what, just "cause it wants to."
Yep, everybody is right on with the hp % loss. I have dynod 9-10 or the cars I have owned and two were engine dynod and then chasis dynod. My 94 LT1 Formula lost 21% through its Auto and my 300Z TT lost 16% through its 5 speed.
When I first got into modding it took me a bit to wrap my head around the percentage loss wrather then just a base number but thats how it is
BTW, my Z was making 421 rwhp and 501 fly wheel hp. When the car was stock it did 254 rwhp and they are rated 300 stock. And that was ZERO mods. So it appears the numbers are right
When I first got into modding it took me a bit to wrap my head around the percentage loss wrather then just a base number but thats how it is
BTW, my Z was making 421 rwhp and 501 fly wheel hp. When the car was stock it did 254 rwhp and they are rated 300 stock. And that was ZERO mods. So it appears the numbers are right
my 04 cobra dynoed 379rwhp sae. car was rated at 390 crank hp. 2.8% loss? 
actually, of all the other cars I've owned and had dynoed showroom stock, the loss was pretty much in the same percentage ballpark:
98 cobra - 264sae/305crank = 13.4%
01 bullitt - 240sae/265crank = 9.4%
02 z06 - 353sae/405crank = 12.8%
06 z06 - 453sae/505crank = 10.3%
the 06 z06 was also under the new, more conservative sae J1349 crank certification that I guess all engines are rated today. so 505 is really conservative for that ls7
the bullitt? don't know on that one....it was just freakishly fast. Dynoed on at least 3 different houston area dynos and just laid the wood everytime. This was one instance where dyno numbers really did equate into street warrior. I use to destroy other gt's and bullitts at HRP. that car was the poster child for factory freak
actually, of all the other cars I've owned and had dynoed showroom stock, the loss was pretty much in the same percentage ballpark:
98 cobra - 264sae/305crank = 13.4%
01 bullitt - 240sae/265crank = 9.4%
02 z06 - 353sae/405crank = 12.8%
06 z06 - 453sae/505crank = 10.3%
the 06 z06 was also under the new, more conservative sae J1349 crank certification that I guess all engines are rated today. so 505 is really conservative for that ls7
the bullitt? don't know on that one....it was just freakishly fast. Dynoed on at least 3 different houston area dynos and just laid the wood everytime. This was one instance where dyno numbers really did equate into street warrior. I use to destroy other gt's and bullitts at HRP. that car was the poster child for factory freak
hotmustang331
Active Member
So if we stuck a 35HP 4 banger engine into your car all you would get is 5RWHP? What happens with a 20HP engine? Are you now in the negative?
Its a PERCENTAGE bro 12-15% on average as others have stated
joshheat25
Member
my 04 cobra dynoed 379rwhp sae. car was rated at 390 crank hp. 2.8% loss?
lol yea I'd say the 03-04 Cobras are a tad under rated!
It is a percentage of loss! one thing to help is to add a lighter Driveshaft, because it is ligher there is less rotating mass and less energy is needed to rotate it.
EPIK
Member
I have always heard the same thing about the percentages too. The higher HP #'s the car has, the more power it loses to the wheels, but the percentage is always about the same give or take....
Since my math isnt that great, what do u guys think my hp & tq numbers are @ the crank on my mach that puts out 315rwhp & 327rwtq???
Mach 1's were rated @ 305rwhp & 320rwtq from the factory(IIRC). My car dyno'd 278rwhp & 294rwtq when it had nothing other than an MRT catted H, bassani catback, & C&L maf... What is the crank hp & tq #'s on that also??? Sorry guys, I am horrible @ math....
Since my math isnt that great, what do u guys think my hp & tq numbers are @ the crank on my mach that puts out 315rwhp & 327rwtq???
Mach 1's were rated @ 305rwhp & 320rwtq from the factory(IIRC). My car dyno'd 278rwhp & 294rwtq when it had nothing other than an MRT catted H, bassani catback, & C&L maf... What is the crank hp & tq #'s on that also??? Sorry guys, I am horrible @ math....
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