trans

[hybrid]

I did a bit of searching on the subject because my car came with a C6 gearbox. Im guesstimating my engine to have around 450HP with the bits I'm putting in/on it, which I'm not sure a standard C4 will like much.
So my options are to sell the C6... who knows how much I'd get for it and buy a tricked up C4.
Or keep the C6 as it will handle the HP.
Then I ask myself the question: Once you trick up a C4, are your parasitic losses higher and approaching the same as a C6 anyway?

Anyhoo.. enough rambling. Here are the figures that many websites are quoting:

Powerglide_____18 hp
TH-350________36 hp
TH-400________44 hp
Ford_C-6______55-60 hp
Ford_C-4______28 hp
Ford_FMX______25 hp
Chrysler_A904__25 hp
Chrysler_727___45 hp


C6 is sucking double the power... 55-60HP is a lot to be losing through the drivetrain

[Foresight]

Interesting, any figures on manuals hybrid?

[hybrid]

Heres an interesting addition!

My machinist has a 650hp Cleveland in his Mustang. He went to a 2 day event and on a Sat. he broke his C4, went home and got his C6 and Car ran identicle times on Sun. w/same weather conditions.

I only saw one manual listed and it was under 20HP. Manuals don't have the heavy shifter drums etc that an auto requires.

[FST68]

Guys,

Just remember these figures that are quoted are based on a certain engine output and should not just be taken as gosple. Any driveline loss will be a percentage of what your engine produces effectively the more power you make the more you will lose through the drivetrain.

[hybrid]

I might just stick with the C6.
I think I'd rather have a reliable box than worry about horsepower loss.

[Foresight]

Ive read that the c4s can be built to reliably handle huge horsepower

[mach70]

Originally posted by hybrid
I might just stick with the C6.
I think I'd rather have a reliable box than worry about horsepower loss.

Your going to have HP loss with any box.

A C6 in normal config is stronger than a normal C4.

When "tricking" them up you will still lose less with a C4 vs a C6 that is "tricked" up the same.

I think the advantage with the C4 is the avialibility of spares etc, as it is more wildely used here in Aus than the C6.

Also the C4 is physically smaller too I think.



Cheers

Shawn

[Cage]

Does anyone know how much horsepower a standard C4 can handle before having to trick it up?

[hybrid]

I wouldn't bother tricking the C6... they can handle the power without mods.
Tricking the C4 may actually make it suck less power... I don't know as I'm not a transmission guy.

Trick bits are definitely more widely available for the C4.

If I had no box in my possession, I think it would be a no brainer, but seeing as I already have the C6, I have to take that into account too.

And yes, the C6 is definitely longer, but I think the crossmembers to suit the T5 should work for the C6. The other thing is having a longer speedo drive made up and shortening the tail shaft. Mine was running already though, so I'm assuming the tailshaft is already the right length.

[FST68]

When I got my new beefed up C$ I was told I would be able to handle 1000hp + havent got that far yet but its never failed even with some serious launches with slicks at the drags.

There are a lot of different mods you can do to a C4 but the biggest things I beleive is the input and output shafts folloI found this to be the weakest part having broken a few.

[evan]

I'm wondering how accurate those figures are. Many years ago, I sold a 351C Falcon that was running a C10 (C4). The new owner 'upgraded' to an FMX & then started complaining about power loss. He ended up rebuilding my old tranny & dropping it back in.

Evan.

[BLKPNY]

FMX?? Don't even bother wasting new transmission fluid on them!

C4's can be built to handle a lot of horsepower, but they cost $$. The more torque you make, the more expensive parts it needs, rather than original parts. A beefied C6 can reuse a lot of the original parts.

Also, the C4 may be able to handle a lot of power, but it won't last as long as a built C6/T400/Glide.

[shaunp]

Originally posted by FST68
Guys,

Just remember these figures that are quoted are based on a certain engine output and should not just be taken as gosple. Any driveline loss will be a percentage of what your engine produces effectively the more power you make the more you will lose through the drivetrain.

I'm not so sure, the energy to turn a gear box would be the same regarless of what HP is bolted to the front of it. I think any box will have a given power waste just like a engine fan.

[hybrid]

I thought that too Shaun and I still do to an extent.

The only way I can see that more HP will mean more loss through the drive train is because more power/torque means you would theoretically have more friction between gears etc because (in laymans terms) everything is being shoved together with much more force.

I still don't think its so simple as a linear percentage though.
If it was 40% for instance, I can't see you losing 400HP from a 1000HP engine.

[BLKPNY]

I heard it takes 850hp to turn a Top Alcohol or Top Fuel supercharger, at 50psi

Although, I would think that it may take 28hp to turn a C4 with 200hp, but if it were 500hp, I'm sure it would absorb more.

[Foresight]

Here is a good article on power loss through the drive train

It attributes a lot of different factors to the loss including engine driven fans, line pressure, friction, torque converter slippage and so on

Here is a link to the summary page

Drivetrain Power Loss - The Brutal Truth

[66FBK]

I have a C6 in my 66. It was setup when I got the car. The original C4 came with the car too but I decided to run with the C6 as it had been reco'ed and the tail shaft shortened. The only thing I changed was the cross member which was a home made job. The T5 aftermarket crossmember fitted perfectly for the C6 and had all the right handbrake machanicals. The trans fluid lines are a tight fit as is the box, but it all fits. The 67 tunnel onwards is bigger I think. Heavy bl00dy lump of a thing though.
Dave

[BLKPNY]

I have both trans in the garage, and wouldn't think (with my measuring arms) that the C6 is too much heavier. I had an FMX, and it weighed a ton.

[MustangNut]

Around 13.5kgs or 30lbs difference. How much is too much?

[BLKPNY]

It's only the difference of a big lunch, in my opinion,  (ok, maybe more...) and not really noteworthy in a streeter. If you are making big torque, it's a no brainer, especially when you factor in the cost.

[shaunp]

Yeah, or use a a toploader with MTF not EP90

[P8TRIOT]

My 351 windsor came with a FMX and it weighs  a ton and a 1/2 . I recently had my motor recond and my mechanic tells me that by changing to a C4 i could save 20% horse power.I havnt tested this theory yet as my project is still happening but i think that is the way i will go. C4s are relatively cheap and you can buy them of the shelf rated at various  horsepower.