Regarding CV in the driveshaft.
I spoke with RCV about this setup:
It turns out that there are two main CV departments at RCV. There's the custom division:
www.rcvperformance.com/store/catalog/index.phpand the regular aftermarket (like parts for Autozone) division:
www.rockforddriveline.com/I was speaking with Russ at the second place (regular aftermarket), who was in communication with the folks at the first place (custom solutions).
The pic above shows a setup from the first place that "never really worked out". Driveshaft CV setups are a different animal than axle setups, because the shaft is spinning 3X the rate. So the setup above wasn't good as the boot would lose shape at high speed, and lose grease, and just not a good solution.
Russ referred me to the yellow catalog on this page:
www.rockforddriveline.com/catalog.htmand then suggested a fixed (non-plunging) joint like this:
It turns out that CVs are used on lots of vehicles today. So we left it open they could be of help with custom fabbing a solution, and I'd do some investigating.
From looking at that catalog, I can see that there are a large number of vehicles that use a CV, so looked to see what was out there, and see what might work for me.
So lots of internetting later, it looked like an aftermarket 2010 Camaro driveshaft was close to what I was looking for.
It had a CV in the front, and a standard 1350 u-joint in the rear.
> It also addresses the weak GM two-piece driveshaft and axles by
> replacing them with pieces built to hold up to well over 1,000 hp.
Read more:
www.camaroperformers.com/camaro-tech/camp-1110-2010-chevrolet-camaro-driveshaft-upgrade/index.html#ixzz1pv6orhhHThe camaro transmission uses a fixed 3-finger yoke.
from
ls1tech.com/forums/gen-5-camaro-drivetrain-tech/1344078-camaro-ss-tremec-tr6060-m10-output-flange-question.htmlSo the CV on the driveshaft shown above bolts to an adapter that bolts to the 3-finger yoke:
Some more internetting later, I found this build of a 1970 GTO:
- 4L80E transmission
- "extreme" front operating angle (driveshaft to trans tailshaft)
- pinion pointing at tailshaft
- 1350 u-joint at rear
- 4L80E slip yoke at front
- 2010 camaro-style driveshaft with CV at front
- built for high speed
Man, this guy's laid it out for me!
Here's the reason why he went with a CV:
> ...when A-bodies are lowered the rear end centerline gets higher than
> the back of the transmission. That is what causes the front working
> angle to become extreme. There are other solutions to the problem
> besides the use of the CV in the front, but that is the route I chose.
ls1tech.com/forums/15935614-post405.htmlHere's a good starting point for reading about his driveshaft:
ls1tech.com/forums/14901794-post368.htmlHe got a custom driveshaft from DSS (Drive Shaft Shop)
www.driveshaftshop.com/And they also whipped up this 4L80E modified slip yoke:
Here's how it all looked:
> ...custom driveshaft with a CV joint in the front. People in the 4x4 world
> have used double cardon CV joint driveshafts for a long time to deal
> with extreme driveline angles. But double cardon joints are bulky and
> heavy, and just didn't seem appropriate for a car. What will be used in
> the front is a 6 ball, Porsche 930 style CV. Like this:
RCV sells a fixed 930 style CV:
www.rcvperformance.com/store/catalog/product_info.php?cPath=22&products_id=66but it really seems that DSS is the sole place to get this done. It looks like they've done several custom solutions like this:
> Interestingly, Frank was building a shaft just like mine for another
> project that had similar driveline alignment issues. It's a custom 1961
> Corvette that will get a monster twin turbo engine.
ls1tech.com/forums/14920621-post373.htmlI found his selection of carbon fiber over aluminum interesting:
> Since a new shaft will need to be fabricated, I have also decided to go
> a little overboard and opt for a carbon fiber tube. This may be a little
> over kill, but I am not taking any chances. In fact, Frank felt that my
> problems can be solved by using a driveshaft made from aluminum.
> However, a CF driveshaft is lighter than aluminum and offers plenty of
> torque capacity. Using a carbon fiber driveshaft also tends to
> significantly lessen the noise generated by the driveline. In some ways
> its like Dynomat for the driveline. I had the opportunity to drive a
> friends RX7 with a carbon driveshaft and it felt amazing. When cycling
> the driveline from load to coast the sensation was like there was a
> piece of plastic between the rear and and the transmission. It was a
> firm feeling, yet it lacked the sharpness that is felt with metal
> components. It was quite amazing.
ls1tech.com/forums/14901794-post368.htmlsome more pics:
> The critical speed for a 54" CF [carbon fiber] shaft is over 8000 RPM.
> My car will never get that that high.
ls1tech.com/forums/14920692-post375.htmlInteresting.
> Gingerman has two long straights where the car can be easily taken up
> to over 120 mph...At high speeds the driveline was super smooth and
> the car performed very well.
ls1tech.com/forums/15056836-post386.html> At the end of my road trip I traveled nearly 4,400 miles in my GTO. The
> car ran beautifully and without any high speed vibrations. Both Nebraska
> and Wyoming have 75 mph speed limits on the highways, which means
> going 85 mph is not a huge deal. The GTO does 85 mph at about 2,400
> RPM and is smooth as silk.
ls1tech.com/forums/15094143-post389.htmlAt the end of the thread, talking about someone else's driveline vibration problem, he writes to ensure that:
> ...all of your various components, such as, output shaft, slip yoke,
> pinion yoke, and pinion gear have run-out that is within tolerance...
Being that he described no problem with the DSS products, I'm presuming the yoke and driveshaft was within tolerance. So for the things I currently own, I need to check my transmission output shaft, and pinion yoke and pinion gear.
For output shaft, it looks straightforward to check, something like:
from
www.vibratesoftware.com/html_help/2011/Diagnosis/Propshaft/Propshaft_Runout.htmFor the pinion yoke, the GTO guy says:
> The first step is to get a rear pinion yoke that is machined with the kind
> of tolerances that are required to achieve smooth operation at
> sustained high speeds. I chose a 1350 billet yoke from Mark Williams:
ls1tech.com/forums/14901794-post368.htmllater on, he writes about it:
> There are numerous machined surfaces that can be used to measure
> runout.
But it seems that ability to measure runout is a different feature than being within tolerance. Possibly my current cast 1350 yoke is within tolerance (just difficult to measure).
It seems that the thing to do would be get a pinion flange runout tool like this:
and measure the axle / yoke combination:
from
www.vibratesoftware.com/html_help/2011/Diagnosis/Propshaft/Propshaft_Runout.htmIf it's within spec, then the pinion gear and yoke are all within tolerance. And if the reading is not within spec, then figure out what's out of whack.
Notice this pic:
The CV is about 4.25" in diameter:
> "930" CV's are also called the "turbo" CV's. They have an outer body
> diameter of 108mm and have 29 splines. The bolt circle is 94mm and
> takes 6 10mm bolts.
www.performanceforum.com/wesvann/914a/know-cv-axle/know-cv-axle.htmlAnd the yoke is a slightly larger diameter than that. Good thing that I have a huge bench seat to fit it under:
your friend in Monaco luxury (except for the front middle passenger that might have more foam and less seat spring than the other passengers),
arthur