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Difference in Chromoly and Carbon Fibre driveshafts
I'm trying to get an idea of the weight and strength differences of a Chromoly driveshaft and a Carbon Fibre driveshaft. I know that Carbon Fibre is lighter than aluminum, but what about Chromoly? I want to be able to go to the track and launch at 5000 RPMs on slicks with 600 RWHP, and not have to worry about it breaking. (No, I'll never have 600 RWHP, but that's the strength that I want)
Id think the carbon would be more likely to break under such circumstances than cromoly... But if it does it wont cause much damage other than paint wear on the tunnel.
If cromoly breaks, its gonna damage something. All of the 10.5 and faster cars Ive seen run a cromoly shaft... Those guys must have some faith in them, cause you know they have deep enough pockets to get the carbon fibre.
Id think the carbon would be more likely to break under such circumstances than cromoly... But if it does it wont cause much damage other than paint wear on the tunnel.
If cromoly breaks, its gonna damage something. All of the 10.5 and faster cars Ive seen run a cromoly shaft... Those guys must have some faith in them, cause you know they have deep enough pockets to get the carbon fibre.
wow, and the carbon fibre is more then 2x the price of the moly. What about weight?? how does the moly compare to the carbon fibre and the aluminum?
wow, and the carbon fibre is more then 2x the price of the moly. What about weight?? how does the moly compare to the carbon fibre and the aluminum?
carbon fiber's twice the price because it's half the weight and if it breaks, it doesn't damage a thing. you get a cleaner undercarriage out of it you pay a lot more for guaranteed safety. not to mention you'll gain some hp out of it.
carbon fiber's twice the price because it's half the weight and if it breaks, it doesn't damage a thing. you get a cleaner undercarriage out of it you pay a lot more for guaranteed safety. not to mention you'll gain some hp out of it.
That's what I though. so, what can a carbon fibre driveshaft handle? the local shop that I"m working with said we'd go with a 3.5" carbon fibre if I decided to go carbon fibre. but, it has to be able to handle a lot of abuse.
The ACPT shafts that I have used live in 1800-2500hp offshore boats. Hell just one race offshore takes more impact loading than an automotive drive shaft would see in its entire lifetime.
Then again, I ulitize the Mark Williams DS more than any other shaft on the market now.
Moly shaft diameter can be reduced to offset the weight isssues without degrading strength. For ultimate strength, the moly shaft will win. On some Land Speed Record chassis, I have used 2.00-2.50" moly and spun it to the moon and back with over 1000hp..... but that is still quite different than a street chassis. The real issue to screwtinize is impact loading.
The nice thing about the CF shaft is that it actually absorbs a very wide range of frequency and cusions the drivetrain. Not to mention that the weight is reduced, but it has a very low MOI and its saftey benefits upon failure are priceless. The only downside that I see, which isnt really a downside for most, is the shaft diameter of a CF shaft to regain the strength ratio.
There are some hybrid's out there now that combine an alloy core with a fiber weave overlay. It reduces the diameter but has the same strength.... with only a slight increase in weight.... but were are talking only by a few ounces of around a single pound.
If I were going to beat the hell out of it at the local 1320, I would go for a small diameter moly shaft. The cost and strength is definately a winner but the small diameter in your chassis make exhaust clearence and fitment easy. I would however, step up to a minimum of a 1350 series yoke and joint configuration so that it pretty much eliminates the possibility of shaft failure.
I used a custom made aluminum shaft in race car...
785hp 600 tq.
Left at 6800 with a Jerico and NEVER broke it. Used 1350 joints. Just a thought for you to consider.
As stated the CF driveshaft is much lighter and will not destroy the transmission tunnel. I have chrome moly with 1350's in the 01 which I'm pretty sure is not the weak link and I have a PST aluminum with 1350's in the 99 drag car that's rated to 1300 hp and I'm nowhere near that power level with driveshaft loops on both.
Lol, yeah. Just a bit. FYI, I have a chromoly DS with 1350s. Don't know how strong it is, but I doubt I'll break it!
With the chromoly driveshafts do they vibrate when you get to highway speeds? Seen some people complain abt that in the past but I don’t remember what driveshaft
With the chromoly driveshafts do they vibrate when you get to highway speeds? Seen some people complain abt that in the past but I don’t remember what driveshaft
I never had an issue with vibration, and with 4.30 gears my driveshaft speed was quite high.
I didn't think I had to worry about my driveshaft, but when I was trying to reassemble it I couldn't get it installed. My new bell housing moved my trans back 1/8" due to the containment plate, and that was all it took to help me discover a big problem. As you can see from the pic below, I seriously twisted the splines in my slip yoke. The rest of my driveshaft is chromoly, but the slip yoke had to be mild steel to twist like that. No big deal, I bought a Sonnax chromoly replacement. Dodged a bullet though! I'm doubling my horsepower and that would have snapped real quick.
09-01-2006, 08:42 AM
Difference in Chromoly and Carbon Fibre driveshafts 
you pay a lot more for guaranteed safety. not to mention you'll gain some hp out of it. 
