rear wheel hp,toploader vs c6

[fryedaddy]

i f you took a,say 500 hp engine and put it in a car,how much hp would you lose on the toploader compared to the c6 at the rear wheels?

[jayb]

Assuming stock internals, the C-6 would eat about 35HP more than a toploader.  That's why the switch to a C-4 is so popular; they take way less HP to run...

[cammerfe]

To a certain extent, it depends on the internals on the C6. Originally, many 'ordinary' bearings in a C6---now possible to rollerize them. Last I knew, Motorsport had some of these parts available. Back shortly after 2000 I did an article for Mustang Illustrated that showed a C6 done-up with an overdrive and the rollerized parts available at the time.

KS

[Katz427]

 I had a discussion about this subject when installing a KenneBell supercharger on my 5.0. Jim Bell figured a C6 or AODE would take about 45-50 peak rwhp compared to a Tko Tremec. These were based on basically stock transmission with higher line pressure shift kit. Amazingly they had tested a couple well put together C4 trans that actually matched the rwhp of a Tremec. I would guess most of these tests were in the 350-500 flywheel hp range.

[Katz427]

I'M doing this from memory, but I believe the number that they used for a modified C6 with roller bearings and all would free up about 20 rwhp. The fact that a C4 has less rotating mass and can be made to live beyond 1000 bhp makes it popular.

[Rory428]

I don`t know about the actual HP differance, but when I switched my Fairmont over  to the Jerico 4 speed, from a pretty goood C6 , which had all the low drag needle bearing internals available from Ford Motorsport at the time, 8" convertor, and Art Carr (Ford Motorsport) trans brake, which allowed for 5200 RPM launches (4500 with footbraking), the car, with NO other changes picked up 1/2 second and 6 MPH in the 1/4 mile. 10.55ET @126 MPH, vs 10.03 @ 132 MPH with the stick. Even the very first pass with the Jerico, with way too much clutch, a low RPM launch, hitting the rev limiter 3 times, and having the car all over its lane, was a 10.26, 3 tenths quicker than the C6s best numbers. Acording to my trusty Moroso Power Speed calculator, that 1/2 second 6 MPH gain was worth 60-65  HP, which sounds awfully high, but the numbers on the ET slip don`t lie.

[My427stang]

Jay or others, are you seeing any AODs or any other OD automatic holding together behind an FE in Drag Week or other racing?

I really like the idea of a strong automatic in both my Mustang and my F100, but want OD and have heard more hate with the AOD than the C-4

[jayb]

I haven't heard anything good about the AOD either; I know a couple people who have had lots of problems with them, despite claims that they can take 1000 HP when properly modified.  I'd never risk one behind a strong FE, when an option like the Gear Vendors overdrive is available.  The C-4 plus Gear Vendors held up well for me on several Drag Weeks, behind 700 to 900 HP engines.

[babybolt]

Since the C6 is a supersized C4, wondering where the additional power loss is coming from?

[cammerfe]

Please explain 'super-sized' as applying to C4-C6. I don't see the comparison except in VERY general terms.

There was a very-viewed 'Turbo' website, frequented particularly by those interested in the '5.0 Ford' Mustangs that took over and wiped-out the Buick turbo craze some years ago. It had a plethora of tech information and many 'sub-' boards. The thinking on the website seemed to be that the C4 could, with proper attention, hold +/- 1000 HP but at that point it was about done. Many of the '5.0' Mustangs had out-powered the C4, according to the comments.

When Jon Corrunker was racing the Thunderbolt, and then the '68 CJ Mustang, he and a guy named Bannister co-owned 'Corban Performance', primarily a Ford transmission shop. I worked at T&C Livonia with Jon and was involved in the goings-on at Corban. At that time Doug Nash was just getting started and was working from his home garage in Garden City. He'd moved past his small-block stocker and had built 'The Bronco Buster', an all aluminum-bodied approximation of an early Bronco---built as a funny car, with a fuel small block. Corban built the C4 transmissions for that car. We rebuilt four of them on a weekly basis, so he'd be able to get through a weekend of racing. He commonly had a C4 last no more than one or two runs.

We've  learned since then, but Jim Paquet of JPT, (Ray's brother) was selling C4 transmissions all over the world---had a world map in his office with colored pins for all his customers---and was also of the opinion that 1K was 'all she wrote'.

KS

[babybolt]

Well, the C4 came first of course, then in general terms the internals of the C6 were based off of the C4 except the C6 got a low/reverse clutch pack instead of a band.  And the C6 gears, etc were larger.  Just can't figure were all these power losses are coming from compared to other automatics.  Windage losses?

[Rory428]

My guess would be mainly from the incresed mass of the much larger internal components. Everything was larger, as the C6 was intended for much more powerful and heavier vehicles than the C4 was designed for. All that extra weight takes power to get rotating and keep spinning. Same reason manual transmissions take much less power.

[e philpott]

C6 parts are huge and heavy compared to C4 is why they rob so much power , Ken no roller bearing ever invented is going to make a C6 equal to a C4

[Katz427]

I read somewhere, that the estimate for losses in the pump and converter, plus windage were on the order of 30- 45% in an automatic.

[Drew Pojedinec]

To a certain extent, it depends on the internals on the C6. Originally, many 'ordinary' bearings in a C6---now possible to rollerize them. Last I knew, Motorsport had some of these parts available. Back shortly after 2000 I did an article for Mustang Illustrated that showed a C6 done-up with an overdrive and the rollerized parts available at the time.

KS

I have a c6/GV setup.  It's freaking awesome for a street car.  Reasonably cheap to build and bulletproof.
I used to have a build of that here on this forum, I moved it to my own page after photobucket killed the links.

That said, if I was racing, the c6 wouldn't be something I considered.  As Rory mentions above, the real deal isn't in HP loss, it's in acceleration of parts.  The c6 drums and rotating parts are considerably heavier than a c4's.