aluminum driveline?

[cryo230]

does anyone have any idea if an aluminum drive line would benefit the svx? if so how much estimated gain?.,....just curious

[cdigerlando]

There are a number of companies that offer custom driveshafts, which is what I am assuming you are refering to. Some make Carbon fiber composites and some make titanium. Later I will post some of these companies. One does not have a web site. That is Paeco. They are the ones that do an engine rebuild on the SVX. The other is a company out of clearwater florida. They do CF and hardened steel. The nice thing about these aftermarket products is they have removable U joints so you don't have to throw away the entire shaft. They are also comparable in price to the OEM counterpart.

Good thread

[maximvsv]

What other engine rebuild and driveshaft sources do you know?

[cdigerlando]

Just Level 10 on trannys. Rebello racing has built SVX engines as well for use in race cars and in airplanes.

[cryo230]

thx chuck, do you think it could possibly make a diff in 0-60 or 1/4 mile? I'm just looking for something to make it a little quicker off the line.

[cdigerlando]

I have no idea. In theory, yes. But then again people who have installed lightened underdrive pullys have seen no gains. The problem with OEM is that they are very expensive, and the U joints are pinged (if that is the right word) into the shaft. So when the joints go, you have to get two very expensive half shafts.

These aftermarket shafts are close to the same price as OEM and should last a lifetime, provided you don't smack and bend them or exert them over the torque spec for which you had them built. Also you can remove the U joints from the shaft when they go, which is much less expensive than replacing both of the half shafts.

This is the kind of modification you do when you have to replace an OEM part IMHO. I think the gains would be minimal.

Chuck

[SVXtypeR]

The slight loss in rotational mass (titanium is only about 1/3rd lighter than steel) would not be worth the EXTREME expense of machining a Ti tube of that size (have you priced that stuff lately? GEEEZZZ!!)

If you're serious about a reduction in rotational mass (to spool up the motor faster) doing *just* the propeller shafts ain't gonna help much. You'd have to combine this with a magnesium wheel/ light tire combo, shaved/drilled flywheel, lightened torque converter (don't know what the stock one is made of), knife-edged crank, titanium connecting rods, AND a *complete replacement* of the transmission internals (especially the main drum) with Carbon fiber/aluminum/Ti alloy where applicable.

BTW- the best material for propellershaft mass reduction (price *and* performance wise) would be carbon fiber.

[cryo230]

well I am glad I asked, I hoped just the driveshaft would do some...doing all that is just overkill for the svx... I'll just get nitrous. LOL

Dave

[cdigerlando]

I believe that any mass reduction on the driveline would reduce the inertia of the driveline. I agree that the wheels, flywheel, and crank would impart more inertia due to the greater off center weight, and that these would be more effective as modifications. That is another reason why I suggested only doing this as a replacement when OEMs go bad.

I have a source for CF shafts, which is what I was going to go to the next time I needed new u joints. I have heard that CF shafts flex a great deal and you loose power responsivness from the steel.

The source (Paeco) says they make shafts for somewhere around $1,200 which I thought was real reasonable for titanium. Also titanium will be stiff, so that there is not as much flex as with the CF.

Maybe one of us should try the CF and the other Titanium. Then we can swap cars and see which is better. Nothing like a good real world experiment to determine what really works best.

[SVXtypeR]

Originally posted by cdigerlando
I have a source for CF shafts, which is what I was going to go to the next time I needed new u joints. I have heard that CF shafts flex a great deal and you loose power responsivness from the steel.

The source (Paeco) says they make shafts for somewhere around $1,200 which I thought was real reasonable for titanium. Also titanium will be stiff, so that there is not as much flex as with the CF.

Maybe one of us should try the CF and the other Titanium. Then we can swap cars and see which is better. Nothing like a good real world experiment to determine what really works best.

CF is an amazing thing. Dependant upon the weave, you can manipulate the tensile, compressive, shear and whatever type of strength you can come up with even with the same shape object.

I once was privy to a class on laminate / composite construction (this class is what got me hooked on laminate construction). I watched as the guy giving the class took serveral CF rods, each exactly identical at about 1" around and about 3 feet in length, and subjected them to a battery of tests.

A rod wovern one way was hammered on it's end (while resting on the floor) with a 5lb sledgehammer repeatedly with no discernable damage whatsoever, he proceded to take the same piece in his hands and snap it in two like a toothpick with very little effort.

The second demo using an identical rod was more interesting. He took the rod, set it crossways on a brick, got the biggest dude in the class (some mechanic that looked kinda' like Jessie Ventura) made him stand on one end while he stood on the other end and BOUNCED UP AND DOWN REPEATEDLY!! He took the same rod in his hands, took the sledgehammer, and with one strike, NEARLY SHATTERED the same rod down 1/3rd it's length!!

The moral of the story, CF has to be woven in specific directions to acquire the desired properites (such as the severe shear strength needed for a driveshaft). That's why i'm not doing high-load pieces like a driveshaft, I'll leave that to the pro's. But body panels I'll be more than happy to take a crack at.

BTW- I found a supplier ( www.FibreGlast.com ) that carries nomex honeycomb so I'm using that as a sandwitch between pre-preg CF outside and kevlar inside which will be vacum-bagged. If the piece comes out right, I'm doin' the whole damn CAR!!!

[cdigerlando]

I just posted a request to do fenders in CF. Check the mods section. If you have extra time and want to make some money, maybe you could do these for us. Either that or if we could get in touch with that english company you were talking about and get some molds made.

[SVXtypeR]

I don't have immediate plans for the body just yet. Right now I'm still working on getting the engine management set up (replacing my cracked windshield last week ate into my Haltech money. :mad: ). So I'm set back yet *again*.

I haden't really planned on doing stock-style parts, I'm actually currently working on a wide-body design. When I'm done (hopefully before the 10 anniv meet) I'll gauge everybody's desire for stock style CF/kevlar weave body panels while we're all together. I was actually thinking more of a single piece hood/fender racing-style assembly, but normal panels can be done more easily.

The only problem with custom body panels is that the rear 1/4 panels (fenders) are *structural* and *cannot* be removed without cutting. How to circumvent this has been the thorn in my side as far as designing the widebody goes. I'm more than likely going to skeletonize and reinforce that panel, and then add the CF as an outer skin over top.

Hey Cryo...
don't get me wrong dude, I'm not saying that lightening the driveshaft won't do anything, I'm just letting you know that you'll get more bang-for-the-buck if you take the power-adder route. I'll put it this way, $1200 on a custom driveshaft *might* be worth .1 of a second in the quarter. $1200 on a well-thought out custom intake and exhaust with a piggyback fuel-controller will knock off a good .5 to .9 seconds! (hell, I just gained .1 from removing the turn signal light!! )

[cdigerlando]

I like your idea of skeletonizing the stock body parts. What you need is to find a few wrecked cars and buy those parts cheap so you have a beginning core to work from.

I agree with the bang for the buck thing on the shafts. That is why those types of mods should be done when needed. A subaru driveshaft assembly costs close to $800. $400 extra for titanium isn't bad. You also get to spend considerably less the next time you need U joints, since they are removable.

Too bad about your windshield. I just had the rear replaced this morning. A garbage truck ran a fork through it. The guy also talked me into getting my insurance to cover the replacement of the front windshield which is faiding. I will be doing this next week. No deductable. Gotta love Florida insurance. They cover just about anything with the windshield, depending on your insurance company. Guess they think it prevents accidents from occuring.