I read it....

 

Just so happens I know one of the SLP engineers who worked on the 35mm bar design. Here's his comments. Very interesting stuff:



He gave me a lead on a company that might be able to produce his original design, and it sounds promising. Just to be different, I'm going to follow up on it and see what I find. Sounds like this guy's 35mm hollow bar will work with the normal 1LE endlinks.

 

1.5 seconds a lap isn't shabby at all. Makes me want to keep my 35mm bar....

Also remember, the bar stiffness increases by the 4th power of the bar diameter. So even if the 32.5mm bar was SOLID, it's nowhere as stiff as the 35mm, much less a hollow 32.5mm. Remember, I had (and sold) a 32.5mm hollow bar. I can vouch first hand for the difference. I made all my suspension changes EXCEPT the front bar (Sam was a little slow... just kidding Sam!!!). It finally arrived and I had it installed. WOW! What a difference. Instantly noticable!!! It complimented the rest of the suspension perfectly.

Obviously you and I aren't going to agree here, which is fine, but I sure wish you could at least try the 35mm, especially on the track. I'd love to see the difference in your track times. You never know, it might be 1.5 seconds too!!!!!

 

I'll say this: We've tried using stock end-link on the ST bar, and broken them every time. Snapped, like twigs, gone off the car in a few cases....... Just not strong enough to handle the roll stiffness in that bar. So, if the SLP 35 isn't breaking them, there is a clear difference in stiffness between them.

I'm doing my level best to get a hollow 35 made. I had a prototype done, but some bends weren't up to my liking and I'm having a miserable time getting it changed. If it ever gets done, it'll probably be less than $200. Hopefully it'll happen.

I'd prefer a hollow 36 for a decent price, much like Hotchkis has, but won't sell without that oversized rear..... But that's another matter. Until then, I'll carry the extra 17 pounds or so and save a couple of hundred bucks....... The roll stiffness is more important than the weight IMHO.

FYI, I've gotten some of SLP's "bushing bracket was a re-inforced production piece", it's so easy to do it's sad. I had modified some of my own prior to seeing SLP's, and beefed them up even more than they did. Just a metal plated welded in vertically to brace two of the legs. We added a second plate and braced all 4.

And yes, 1.5 seconds a lap ain't too shabby. Nice to see some props from folks running on the track for that bar that was just too big........ It's happened on LS1.com and now they fellow who worked for SLP mentioned it was a bunch quicker than with a smaller bar..... Whew, vindication.

 

Not me. That car in the example was running stock springs. Different comparison altogether.



Yes, I know. I was assuming the Hotchkiss bar the guy was talking about was 35mm OD and hollow. If I'm wrong, I misunderstood.

When I find a good hollow 35mm bar I'll likely try it. Why settle when you can have the best of both worlds I always say.

 

What I read above is all the endlinks and bushing brackets were upgraded for the original SLP design, and the one that is currently being sold uses heim joints. I'm not sure I understand your conclusion.



You can't use your marketing savvy to get Hotchkiss to sell the front bar by itself? I'll buy one if you can, and I bet others would also. I'd try it next year if I didn't have the big weight penalty to pay along with it. I can always go back to my 450 front springs if it's too much for my driving style.

 

Yes you can. And unless Gary Pinkley of Hotchkis lied to me, they did. He specifically told me their front bar is 10% stiffer than a solid 34mm bar. That puts it right on par with a solid 35mm for stiffness.

WOT, I backward calculated that to a wall thickness of about 4mm (.157") based upon an advertised diameter of 36.5mm. Probably not exact, but it should be pretty close.

 

Jon, so based on the posts on this forum and the other one I take it you're going to try the Hotchkiss bar system instead of just the front bar? What's the going rate for that combo and did you happen to ask if there was a way to just buy the front bar?

 

Yup, I'm going to try them both. TByrne has the set for $419 (what do you think you could get them for, Sam?) which isn't too bad if both bars work well.

If not, I should always be able to sell the rear to a dragracer and the front to an autocrosser. But right now I think they should work together well for roadcourse work. Time to see for myself....

 

Any plans on strengthening the mounting brackets for the front bar? As has been mentioned a lot it appears to be a regular occurrence for some people with the ST bar.

 

I think I'll pick up a couple of extra brackets and see how it goes. The bigger rear bar and stiffer springs will reduce the loads on the brackets, all else being equal. However, tracks that require shortcuts over curbs may mean things aren't quite equal....

 

whats happening with the mounts on our cars? are they breaking? and should i weld in some plates on the body side of the mounts? sorry i was skimming and want to go to bed. thanks Trey

 

I'm sure we could work it out.....

 

This was stated by the engineer: "The Production 1LE 35mm bar (my design) used special end links (the hardest that ITT makes)" That implies to me that they are using the hardest bushings ITT makes, which also implies it's a standard endlink design. Assuming (and I don't know) that the stock links are also ITT (and they do use a very hard plastic material) it tells me the bar is less stiff than the ST since the ST bar snaps stock and 1LE links easily. Every 1LE I've ever worked on had the same links stock as any other Z28 or Formula.

I'm working on a hollow bar, really. But since the ST is out there, and works, and is cost-effective, and isn't tons heavier than a hollow bar, I'm not going to rush into something that doesn't fit to my satisfaction.

 

Dammit. I'm an idiot. 4mm, .157" or roughly 5/32" is indeed the wall thickness I estimated given the relative stiffnesses Hotchkis provided me for their REAR bar! based upon a 1" OD.

For the FRONT bar it came out to be a bit over 6.25mm, or .250" wall thickness.

Sorry guys. I guess that's what I get for trying to hurry a post when my wife is calling me for dinner.