Both of these drive shafts say they are direct replacements but the Inland is 41.750 in center to center and the Summit is 41.625 in center to center. I've read the most 3rd gen driveshafts are 41.50 center to center so are these really direct replacements or do I need to have one made ?

 

You're talking about 1/4" difference at the extremes. Not enough difference to worry about.

 

It will be fine

 

Thanks for the info, about to order the summit driveshaft

 

I realize this was a few years ago, but did you end up buying one of those drive shafts? I am considering going to an aluminum shaft now...

How was the quality and the fit? Did you actually notice a difference driving the car? Improved acceleration? Reduced vibration?

 

Yes a quality aluminum driveshaft will reduce vibes if your OEM shaft is out of balance or not straight. Back in the 90s I bought the 1LE shaft for my 84Z28 and all the problems with driveshaft vibes were gone. Quality of OEM steel shafts isn't the greatest and if you have short gears that spin the shaft faster at a given speed, vibrations show up. Not as much a problem if a car as like 2.73 gears. The aluminum LS1 shafts are a bolt in also if you're not going to beat on it hard (ie a high torque motor launching on slicks).

 

Inland Empire Drive Line probable makes what Summit sells Inland makes up all of what they sell. They do buy parts for what they put together though.
Call Inland Empire Driveline (909) 390- 3030 talk to Carlos he can answer any questions you have.

I know it's an old posting , my Added information is for others that might Resurrect this old post.

 

I ended up calling Inland Empire to discuss their drive shafts. They confirmed that they use maintenance free joints, instead of the greaseable type. He explained that the greaseable ones are nice since they can be re greased, but they usually are made to looser tolerances and after running a short while some of the grease slings out and leaves the fit somewhat loose. The maintenance free ones instead are sealed with all the grease they'll ever need trapped inside. They're also machined to tighter tolerances with better surface finishes on internal components, so in the end they are usually considered the better options for performance use like ours. The Summit shaft has a seal front but greaseable rear, I believe...

I also noticed some inconsistency in the finish of the front transmission yoke. In some photos it was black oxide treated, and in others it appeared raw steel. Turns out they do black oxide most of their transmission yokes, but in the case they have a lot of orders that will be shipping quickly, they sometimes skip the step. He said it was more of a preservation for while they sit on their shelf, not for operation, but he said if I wanted, I could specially request to make sure I got a black oxide one, for no additional charge.

In the end I ended up ordering the shaft from Inland Empire with the black oxide treated transmission yoke. I've received it and installed, it yet I'm still completing my custom fab front drive shaft loop, so not miles on it yet... Looks like a very nice part. It is also moderately lighter than the steel 2.5" stocker which weighed 15.98 lbs. The new Inland Empire 3" aluminum shaft weighs 10.84 lbs!

 

It's too small of a diameter to make a measurable difference. Only reduced vibration would be if there were something already wrong, with your previous drive shaft. You're saving 5 lb. The biggest reason to have one is that it's "Cool"......and I "get that"; I replaced two steelies with two aluminum in two F-bod's. But from a real, meaningful/measurable standpoint, it's not noticeable or measurable.

 

If you're already making any semblance of power, you probably won't see a big difference, but if you've got a stock, smog-choked motor (or a V6), you can actually feel it. Going from the stock steel DS (16lbs) to an aluminum 1LE shaft (8lbs) dropped a whole second off the 0-60 in my 3.1 lower power motors really appreciate having less rotating mass behind them, but the differences will be less apparent the more power you make.

Edit: Just to clarify, I know he has a 383 and already had a driveshaft made, but I figured I'd throw that in there for anyone who may come across the thread later with the same question. Great lookin build btw, I dig the custom safety loop you're workin on in the other thread

 

Thanks LLCool!

Since I'm it's just easier, I had Google Gemini calculate the difference for me. The inertia for the AL shaft is only slightly less than the steel one because of the diameters, but it is still an improvement there, 2.3% difference. Not to mention, the overall weight savings of 5 lbs, and frankly I feel like the performance ones are just more accurately balanced than the factory ones, or at least the current state of balance after 152k miles.

 

I'm sorry....but N....F.....W.
Something else dropped your time by0.9999999 and the drive shaft dropped it the remaining 0.00000001. How many HP do you think that it takes to accelerate a 3" aluminum tube from 0 RPM, to ~3000 RPM over....what'd your car run....8seconds? I'd bet 1hp could do that easily.

What were your trap speeds in the 1/4 before and after? :bigears:

That.

And that 2.3% is the diff in the driveshaft comparison....when you add 3100 lbs of CAR to that, the 2.3% becomes unmeasurable. Meaningless.

The main benefits of going with a quality aftermarket (aluminum, carbon fiber or even steel) is first, to raise the critical speed of the drive shaft for top speed runs, and second to make it stronger for drag track launches with you know...slicks, aggressive clutches, etc. Most of us aren't in the realm of wanting or needing that expense for those types of benefits. Mostly, AL driveshafts just look cool and are "nice" to have. I liked having one....couldn't tell the diff, by driving it or drag tracking it.

 

This was a few years back, while I was still in college lol. In fairness, I was usin a free app to time it, but I ran it a few times with the steel shaft and aluminum shaft and averaged it out. Nothing else about the car changed but the driveshaft, pretty much stock aside from the wonderbar and a cone filter. Anyways, sit down for this one, she's a real ripper.... steel driveshaft averaged a 12.4 second 0-60, 18.6 sec quarter, trap speed of 83 aluminum DS average was 11.3 sec 0-60, 17.83 quarter, 85mph trap. I still had an open rear and the 700R4 at that point, who knows, maybe I got her down to a 10 sec 0-60 nowadays haven't bothered getting times since then, as funny as it is, since it isn't a racecar, still my daily. Heck, only reason I even got the 1LE shaft back then was that a buddy of mine gave me a smokin deal on it, figured the lil 3.1 needed all the help it could get. Maybe the difference was just my driving, or the stretch of road, or whatever, but it was consistently around a second lower in the runs I did after the driveshaft, could tell it wasn't struggling quite as much to rev. The respective runs were done about a week apart as well, in the same weather, both on flat ground (i.e. not on a hill). Wouldn't mind getting a proper time at a track one of these days, but my steel driveshaft is long gone, so I wouldn't be able to get any comparisons. I do appreciate you giving the 3.1 the benefit of the doubt on an 8 sec 0-60 though! If only
I'll do somethin about power one of these days, but hey, it's kinda fun to be able to keep the pedal to the floor and not worry about a felony!

 

Yep. IDK.

If you think about the engine that would be require to spin either of those shafts up to ~3000 RPM over 11-12 seconds.....that's a pretty small engine. Like an RC car engine. Now compare the RC car engine needed for the steel shaft, vs. teh RC engine needed for the AL shaft, and there is your "freed up power" diff. Weeny-teeny.