Transmission HP loss

[THE BOMB]

This may have been covered in auto vs manual before, but, does anyone know the HP loss: auto vs manual on the Mustang GT? Trying to decide which to order. I know the auto is faster but that doesn't mean it has a lower HP loss. Any input?

THE BOMB

 

[THE BOMB]

Come on! No one knows!

 

[Nolyaw]

The manuals dyno @260-270 hp. Ive seen the autos @ 250. It takes more to turn that auto. Also, your resale will suck when it comes time. Plus when that baby runs out of warranty, look out!

 

[cleveland]

The manuals dyno @260-270 hp. Ive seen the autos @ 250. It takes more to turn that auto. Also, your resale will suck when it comes time. Plus when that baby runs out of warranty, look out!

Says the guy who knows resale values. I higly doubt the resale values will suffer for an auto over a manual.

You should really come up with better "facts" why not to decide on an automatic tranny.

-Dan

 

[300bhp/ton]

This may have been covered in auto vs manual before, but, does anyone know the HP loss: auto vs manual on the Mustang GT? Trying to decide which to order. I know the auto is faster but that doesn't mean it has a lower HP loss. Any input?

THE BOMB

When you say faster how do you mean?

A well driven manual should be the quickest over a set distance and also quite a bit faster on the road or at a track day. An auto box will never give you, ie the driver the control they need.

If its just drag racing, then an auto will give you very consistant times as all you have to do is sit back and hit the loud pedal - yes it really is this simple regardless of how many people claim there is more to it.

As for HP loss, well don't worry about it. The auto can change gear quicker than a human hence the times are still similar.

And for how much it actually looses, well this is a very broad subject with lots of theory's and opinions.

However remeber HP numbers do not win races. Driver skill and deployable power does.


If you want a cruiser without the challenge of shifting at the track get the auto.

If you want the fun and levels of satisfaction that only a manual can bring and are prepared to sit in traffic with you foot on clutch, then the manual is the only option.



Its a bit like only having ever drunk alcohol free beer (autobox) then suddenly being introduced to some 5.5% beer (manual).

-Both will give you headache in the morning, only ones a lot more fun!

 

[300bhp/ton]

Says the guy who knows resale values. I higly doubt the resale values will suffer for an auto over a manual.

You should really come up with better "facts" why not to decide on an automatic tranny.

-Dan

reading between the lines Dan, I agree with you. Nolyaw is acting a bit of a dick, and the more they post the worse it gets.

As for resale value, well it might. Def does in the UK. A manual Z28 will fetch upto 50% more than an auto.

Typical 01 Z28 auto £10k
Very rare and hard to find 01 Z28 M6 £16K

But I know auto's are popular in the US so it may be a different story.

 

[AJC-05GT]

rumor has it that for the 05 mustang about 13% loss on manual an 18% on the auto.
Usually I see people use around 15%+/- for a manual and up to 23% for automatic..here is a good article on HP and torque

http://www.car-videos.com/articles/horsepower_torque.asp

Manual gear ratios
3.34 / 2.00 / 1.32 / 1.00 / 0.68
final drive ratio 3.55

Automatic
3.25 / 2.44 / 1.55 / 1.00 / 0.75
final drive ratio 3.31

 

[300bhp/ton]

rumor has it that for the 05 mustang about 13% loss on manual an 18% on the auto.
Usually I see people use around 15%+/- for a manual and up to 23% for automatic..here is a good article on HP and torque

Remeber these are only guesses, as every car will have different looses, and it would be silly to assume that a1960's muscle car has the same loaas as a modern fwd hatch producing the same amount of power.

Example a 5.0 60's Mustang was rated @ 250bhp Gross so would have been about 190-200bhp by todays standards.

Yet a Honda Civic Type R also has 197bhp.

Working on the 15% rule they would both loose the same thru the transmission. But do you seriuosly beleive that a modern lightweight compact drivetrain like the Honda's will loose as much as the slightly more agricultural setup on the classic Mustang. For most people the best you can do is dyno the car STOCK and correct the numbers to SAE Net stadards (although this is still inaccurate as Mustang dyno's and Dynojet will still give different numbers) and compare to the factory rated output. This variance will stay pretty much the same with small mods and slowly increase with the more power the engine produces - its only a guess, but educated.

If your STOCK (Must be STOCK) 05 GT dyno's a rwhp of 260rwhp the 15% rule would give you 305bhp - THIS IS LIKELY TO BE WRONG.

What is more feasable is that the drivetrain is sapping slightly more power. It also depends on how you calculate it. As is it a 15% from 300bhp OR the engine is producing 15% more than the 260rwhp????

If the engine is making 300bhp, then 260rwhp is a 13.3% loss of power from the engine, or an easier way know you have found the variance of 40bhp it is easier to assume tthat this will remain fairly constant unless drivetrain components are changed.

So if you mod your car and get 310rwhp + the 'known' loss of 40bhp will give you a realistic engine output of 350bhp. Due to friction the loss may increase slightly but as the drivetrain components have ot changed this increase should only be slight, maybe a 2-5bhp more.

The reason people don't like working it out this way, is the simple fact that it will not produce such big numbers. If you still assumed a 15% with 310rwhp it would give you 365bhp - personally I feel this is not only optimistic but unlikely, the physics just don't add up.