924RACR

Already have 30mm, trying to find source for something bigger. Anyone have any suggestions? I thought they were available up to maybe 34 or 36mm, custom order? I'm not allowed to use coilovers in my race class, but really need to bump up my spring rates a good 50% still... which would be another 300# or more of coilover spring in addition to the t-bars, or just swap in a set of 33mm t-bars.

Sure, I can add a little bit of roll resistance through a 22mm rear sway bar, but not enough, and the car still squats quite a bit (got the pics to show it). Biggest issue, however, is the lack of roll resistance resulting in eating tires up. Car is balanced and flat, but eating outside edges.

Any advice and direction would be appreciated. I'm on the podium, but looking for more...

Thanks!

M758

Talk to Jason at Paragon. We talked some a few years back and he said that it was pssible to go to 32 or may be 33 mm t-bars. I don't think you can go much thicker due to the size of the splines.

M758

PS.. in my 944-spec I don't have any issues with tire wear on the outside edges. I run 3.5 deg negative front and 2.5 deg negative rear. Wear is quite even accross the tire. I run 350lbs from 30 mm t-bars adn the weltmeister 28/22 sway bar combo. My car does run at 2450 lbs so that may be an advantage for me.

924RACR

Hope so, already sent an email his way (first thought)... hope he comes back with a yes. Still, good to hear - I'd thought I'd seen something about larger dias being available custom...

Thanks... anyway, what do you guys run in Spec, anyway? Probably coilovers if anything other than stock, since they're so much cheaper and easier to deal with? Makes sense... unlike SCCA... j/k

924RACR

OK, questions crossed in the posts... thanks for the added info. How do your temps look? I'm at 2600# (IT weight), plus less swaybar, and less front camber - 2.5 all around. The only thing I can't easily do that you are doing is the front swaybar - have a different front mount. OTOH, springs are easy. We'll see how the custom bars price out; may just use a larger rear bar and much more front spring to even it out.

Thanks!!!

M758

Well,
we are "spec" so that limit rules some times.

We are NOT allowed coilovers and since there are custom t-bars out there we also limit rear t-bars to 30 mm. This keeps the suspension softer over all and the entire set-up works pretty well on cars of our weight. We also don't allow proper race shocks. We can just use Koni yellows or Bilstiens. Nothing fancy. These are in the rule to keep costs down and the focus on drive and not car prep. I think 95% of spec guys run the 30 mm t-bars. The fronts are abit more varried going from 250lbs springs to 400 lbs 2.5" springs. Sway bars range from Weltmeisters to 968 M030 to 944 Turbo units. We run 2600 min with driver so my car is 2450lbs

No idea on tire temps, but wear patterns over many track days have proven to me the the setting are pretty good.

You should be able to fit a weltmeister front sway bar?

I personally would not go stiffer than 400 with 30 t-bars. I think it will throw you balance off. I would how ever go with more negative camber if you go stiffer or no. Guys that run 250 lbs springs often run 2 to 2.5 deg negative camber in front using the stock strut. They get outside shoulder wear. Most guys with camber plates can get more negative camber in front and much less outside tire wear. In fact I think the inside is slightly more stresses. I do rotate the the tires after every track day to keep them wearing evenly.

macnewma

PM Ski, he has some 32mm bars.

Max

Geo

Vaughan, Paragon is definitely the place to go. I have a set of custom 32mm hollow T-bars for my car from them already. I know they can get 33mm and perhaps even larger.

Geo

Swaybars and mounts are free.

They cost the same as the Weltmeister hollow bars.

924RACR

Yes, swaybar and mounts are free - but the 924 uses a completely different front swaybar mounting/setup than the 944 - it's bolted to the frame, not the a-arms! But thanks guys - you've pointed me in the right direction!

Data, G-sum, and yaw rate plots to follow from this past weekend.

Geo

I still don't see the problem.

I'm not going to use the stock mounts, bar, or attacments (neither frame nor a-arms).

I also don't get what you're saying. You typically tie the end of the bars to the suspension components (arms or strut or upright) and attach the middle portion to the frame so the bar can twist. How is the 924 front bar set up?

BTW, the 924 manuals SUCK. They don't even cover the swaybar so far as I can find.

924RACR

It's just the additional fabrication required, PITA factor. Not impossible, just extra work. Not that swapping torsion bars isn't! But springs are easier.

The 924 front bar mounts are bolted right up to the frame rails, not hanging below. No triangulation needed. Then there's drop-links down to a tab on the a-arm at the ends. Pics in here; swaybar is black and hard to see, but the drop-links are new (they break) and shiny plating:
http://www.vaughanscott.com/construction.htm#SUSPENSION

The 944 bar, in contrast, hangs below the front frame rails and bolts directly to the a-arms without drop-links, only with bushings. Least that's my understanding.

Also, as promised - data from this weekend! LOL Yeah, I posted it on my website. Didn't bother doing screen captures to post - too hard to read, I want the raw data myself. Amusing... I recorded a peak lateral accel of 1.3g, at the same time as a longitudinal reading of 0.15g. Peak values as the car was hopping sideways; a very fast sector time, but that's only coincidence. Anyway, the data's at:
http://www.vaughanscott.com/AIM/aim_tracks.htm (as well as track map if needed)

Geo

Do it big guy!

I hate the stock 944 set-up. Looks to me the way the bar slides in the bushing that the bar rate would be variable as the suspension moves and what's worse is the bar rate would decrease with greater travel.

Why not just build 3-piece bars? Pretty simple to do. Use heim joints for the drop links for positive effect. That is what I plan to do. In fact, now that I see where the 924 bar mounts I'm going to see if I can mount mine in the same place. No need to use the tab for the drop link mounting either since there is a hole in the control arm.

924RACR

You are correct; that's what they did on the 933 and/or GTR's. Very cool custom setup. However, photos taken trackside (of my car, not on the website yet) show quite a bit of squat on acceleration in 3rd, accelerating at about 0.2-0.3g indicated. This would also confirm the desire for more t-bar in the rear, IMO... the old trackside data acquisition system! LOL

Geo

Oh, I'm not saying not to use bigger t-bars. I've long thought the commonly used t-bars are too light for a track only car. I'm wondering if the 32mm bars I have are going to be enough. I had to make a guess (between 32 and 33) because the only people I knew using them are the 951 guys. It also seems the F/R balance the 951 guys like is different from the NA guys. More guessing.