Anyone pushing 450 + on a stock clutch??
09-22-2012, 05:57 PM
#1
6th Gear Member
Thread Starter
Join Date: Aug 2007
Location: MO/ Born and raised in Louisiana
Posts: 10,696
Anyone pushing 450 + on a stock clutch??
Just wondering what's the max rwhp a stock New Edge clutch can handle. Once I get the car back I'm looking (hoping) to be right at around 450 to the wheels, so that's why I ask. I had a spec stage II but it (our of nowhere) went out on me ( a month before my engine went up in flames). Also anyone know what a stock 3650 tranny can handle? Thxs
09-22-2012, 06:14 PM
#2
4th Gear Member
Join Date: Feb 2008
Location: Georgia
Posts: 1,761
Don't know if it's the same as the new edge GTs but I still have the stock clutch in mine. I don't really race it though.. I have a McLeod sitting in the garage though for when it does decide to go..
Also have a 3650 in mine, again don't really abuse it though.. From what I do know though, they will give pretty quick if you're doing a lot of hard driving..
Also have a 3650 in mine, again don't really abuse it though.. From what I do know though, they will give pretty quick if you're doing a lot of hard driving..
09-22-2012, 06:14 PM
#3
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Join Date: Jan 2007
Location: MI
Posts: 5,884
Well I had the stock clutch on my 04 gt for 3 years with the nitrous, and it showed no signs of significant wear. Of course it was a cammed nitrous car with about 400 rwhp and 500 rwtq, but that massive torque never killed it lol. I was on dr's pretty much the whole time as well. IMO it has a lot more to do with how you drive your car vs a particular hp number
09-22-2012, 06:41 PM
#4
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
Power transmission products, clutches, transmissions, rear-ends or whatever are not rated in HP--but rather torque capacity--so rpm, input and output, must be considered in any discussion of design parameters.
There are no published Ford torque specs for the stock clutch of which I am aware, however many aftermarket clutch vendors make claims for their packages that let us sort of "reverse engineer" the stock rating. One that I am quite familiar with is the RAM HDX kit, for which RAM claims 450 lb-ft torque capacity--that being 150% more than the stock clutch. Making their impression of the stock assembly's capacity 300 lb-ft.
In my experience this is rather close to the reality of the situation, I have seen and heard of a number of stock clutches (including mine) that didn't like it/let go when they were asked to aggressively handle anything much in excess of 300 lb-ft.
Assuming launch/peak torque rpm of 4800 to 5200, 300 lb-ft = 300 * 5000 / 5252 = 285 HP at the input to the clutch--I.e. the flywheel. Seems safe to bet that it is not going to deal well with 450 at the wheels, 530 or so at the flywheel.
The 3650 is rated for 360 lb-ft maximum input torque, using the same 5000 rpm peak torque base as above, this is 360 * 5000 / 5252 = 342 HP at the input shaft. Here is a great article from Transmission Digest describing the 3650 in depth, and dispelling many/most of the "crappy transmission" chatter we hear all too often.
The rear-end will be a weak point, here's a post from earlier this year looking at the read-end capacity.
An important, but understated point in that post is that tire traction, or more correctly lack of same--the ability to connect with the track--behaves empirically as a torque limiter. If you had 4.10 gears, and your tires broke loose at 3500 lb-ft torque, then the pinion gear (and tranny output shaft) will see 3500/4.1 = 850 lb-ft torque. If that happens in first gear (3.38:1 in the 3650) then the tranny input shaft will only see 850 / 3.38 = 252 lb-ft. Piece of cake, well under the 360 lb-ft rating.
This is a bit of a ramble as my daughter, grandson and wife, and great-grandson are visiting; and being quite worn out I snuck off to do this--let me know if I need to make more sense of any of it...
There are no published Ford torque specs for the stock clutch of which I am aware, however many aftermarket clutch vendors make claims for their packages that let us sort of "reverse engineer" the stock rating. One that I am quite familiar with is the RAM HDX kit, for which RAM claims 450 lb-ft torque capacity--that being 150% more than the stock clutch. Making their impression of the stock assembly's capacity 300 lb-ft.
In my experience this is rather close to the reality of the situation, I have seen and heard of a number of stock clutches (including mine) that didn't like it/let go when they were asked to aggressively handle anything much in excess of 300 lb-ft.
Assuming launch/peak torque rpm of 4800 to 5200, 300 lb-ft = 300 * 5000 / 5252 = 285 HP at the input to the clutch--I.e. the flywheel. Seems safe to bet that it is not going to deal well with 450 at the wheels, 530 or so at the flywheel.
The 3650 is rated for 360 lb-ft maximum input torque, using the same 5000 rpm peak torque base as above, this is 360 * 5000 / 5252 = 342 HP at the input shaft. Here is a great article from Transmission Digest describing the 3650 in depth, and dispelling many/most of the "crappy transmission" chatter we hear all too often.
The rear-end will be a weak point, here's a post from earlier this year looking at the read-end capacity.
An important, but understated point in that post is that tire traction, or more correctly lack of same--the ability to connect with the track--behaves empirically as a torque limiter. If you had 4.10 gears, and your tires broke loose at 3500 lb-ft torque, then the pinion gear (and tranny output shaft) will see 3500/4.1 = 850 lb-ft torque. If that happens in first gear (3.38:1 in the 3650) then the tranny input shaft will only see 850 / 3.38 = 252 lb-ft. Piece of cake, well under the 360 lb-ft rating.
This is a bit of a ramble as my daughter, grandson and wife, and great-grandson are visiting; and being quite worn out I snuck off to do this--let me know if I need to make more sense of any of it...
Last edited by cliffyk; 09-22-2012 at 06:43 PM.
09-22-2012, 07:47 PM
#5
I blew out 2 stock clutches in mine before i went with the centerforce, first one blew with around 420rwtq and the last one blew with my current 436rwtq, not saying they wont last with more than that but that's my experiences with over 400rwtq and a stock clutch
09-22-2012, 08:51 PM
#6
TECH SAVANT
Join Date: Dec 2006
Location: Saint Augustine, FL
Posts: 10,938
400 lb-ft at the wheels is pushing the stock clutch for all it's worth. It defines the difference between "rated" capacity and "what it will do"...
I don't care about what anything was DESIGNED to do, I care about what it CAN do.
And there you have the fundamental difference between wussies and men...
Originally Posted by "Gene Krantz" in Apollo 13:
I don't care about what anything was DESIGNED to do, I care about what it CAN do.
Last edited by cliffyk; 09-22-2012 at 08:55 PM.
09-22-2012, 10:12 PM
#7
4th Gear Member
Join Date: Jun 2009
Location: Arizona
Posts: 1,147
My stock clutch was slowing going out so that is why I went with the CF DF clutch. I know I am only at 400rwhp, but only after 25,000 miles I could tell it was slipping bad. This was confirmed when they pulled the flywheel. It was only a matter of time. The CF grabs like crazy and you can feel it. If you do go with an aftermarket don't go with Spec, go with CF or McLeod.
09-23-2012, 08:44 AM
#8
My stock clutch was slowing going out so that is why I went with the CF DF clutch. I know I am only at 400rwhp, but only after 25,000 miles I could tell it was slipping bad. This was confirmed when they pulled the flywheel. It was only a matter of time. The CF grabs like crazy and you can feel it. If you do go with an aftermarket don't go with Spec, go with CF or McLeod.
09-23-2012, 09:47 AM
#10
6th Gear Member
Join Date: Jan 2007
Location: MI
Posts: 5,884
I agree, a good twin disk setup is far more enjoyable to drive overall, and can hold up to whatever you throw at it...if you get the right one of course. I just went with a McLeod RST twin disk on my SS, and it feels like stock but will hold up to 800-900 hp/tq. Of course you get what you pay for lol