Technical Discussion

Stohr Tidbits

feeds@yuku.com (Jake Latham) — Sun, 12 Jul 2009 14:10:02 GMT

All -

A few small tidbits from Stohr, the other day:

1.) on early Stohrs (not sure when the changeover was made), the rear bellcrank results in a motion ratio of around .87, not the 1:1 as intended. An updated bellcrank is available, and is identifiable by two large holes on the side where the shock attaches (i.e. you can use old or new motion ratios if desired). I think they all have the hole at the back where perhaps facility for an anti-roll bar (that was never added)...

Lifting the Stohr

feeds@yuku.com (AZracer) — Tue, 16 Jun 2009 06:45:49 GMT

I was thinking (always scary) that I should get a portable/foldable shop crane (aka cherry picker) and hoist the car up to get the chassis dolllies under.....could take the crane to the race track.... could lift misc motors from misc vehicles.... anyone know where the car's lifting point CG is and if this will work?

How can I support this forum?

Thanks again,
Paul

btw, the car is in route and I ordered the quick jacks from Stohr.

Updateapalooza II

feeds@yuku.com (Jake Latham) — Sun, 29 Mar 2009 19:41:45 GMT

All -

I updated my website tonight. Huge update, so rather than retype it, I'll post a link. Cliff's notes:

1.) Created a Bead seat. Many Kudos to Dean and Pete for their tips. The new seat feels *great*
2.) finished the 'ram-air' intakes for the GSX-R airbox.
3.) did a shakedown of the car at the kart track - no big dramas
4.) switched over to Hoosiers
5.) finally finished the !&#@& harness bar saga.
6.) summary of...

running with/without the intake vents?

feeds@yuku.com (NASA racer) — Sun, 15 Mar 2009 15:10:21 GMT

Has anyone done an A/B test of with/without these vents? I know the Stohrs originally didn't have them and I have pictures of the runoffs where there is a mixed bag of with/without.

The WF1 has practically the same intakes as the 1st gen but without the vent covers.

Curious Cornerweights

feeds@yuku.com (Jake Latham) — Sat, 21 Feb 2009 16:02:22 GMT

All -

Just finished doing a setup on my car for the first time. Most of it was dead nuts already:

Camber: -1.5/-.5 (this is at the high end of recommended)
Toe: 1/32 out (per side) front / 1/32 in (per side) Rear

Rolled the car on the scales and the weights were about perfect, but the ride heights were wonky. After playing with things a bit, I ended up with the following, and called it good enough without knowing more:

Heights: (1"+)
...

Rear Caliper Location

feeds@yuku.com (Jake Latham) — Tue, 10 Feb 2009 17:32:23 GMT

So I've seen the rear caliper in two spots now on Stohrs. Most cars have it at the 12:00 position, right on top of the upright. I've seen a couple, including mine, and the car for sale by Perry Richardson, that have it at the 5:00 position (if looking at the LR of the car), with a different bracket.

My thought would be that it's maybe more convenient in the lower position, since you don't have to tilt the caliper up to bleed it, yes?

Any other...

sproket size ????

feeds@yuku.com (fastercar) — Mon, 09 Feb 2009 06:12:31 GMT

I'm in the process of converting my 1st gen from Yamaha power to an 07 GSXR eng. What tooth count do you guys use on the front and rear sprokets?? Also, any recommended spares to have on hand ??? THx, Dave....

Wilwood pad part numbers?

feeds@yuku.com (NASA racer) — Mon, 02 Feb 2009 11:42:31 GMT

I have the car's original 4-piston front/2-piston rears and understand they are probably Willwood pads. Anyone know the part number?

Header Coating

feeds@yuku.com (Jake Latham) — Mon, 19 Jan 2009 20:38:40 GMT

I had my headers, collector, and part of the exhaust coated by Jet-Hot. I decided to try the "Extreme Sterling" coating. We'll see how useful it is in terms of under-body temperature reduction. Hopefully I'll never test if it helps prevent oil-flash fires.

Before:

After:

Radiator / Oil Cooler intake ducting height?

feeds@yuku.com (Jake Latham) — Mon, 19 Jan 2009 16:34:36 GMT

Here's another one. I saw a picture of Rod Morley's old car, now in Chuck Bona's hands. The intake ducting (the 'spade' dealies that bolt onto the nosepiece) seemed to be at a VERY low height. My car is closer to 2", and the two busa Stohrs here in CO are around 1.5".

Pete, what are yours at? Anybody know what the 'standard' height really is?

I ask since I may play with reducing the height of the intakes and seeing if it has any...

Schroth belts and HANS harness bars

feeds@yuku.com (NASA racer) — Sat, 17 Jan 2009 22:04:24 GMT

So with some help and just trial and error, I got my belts installed.

The belts I ordered were Formula II with the WRAP shoulder harness and, as it turned out, I didn't pay attention and realize I needed 10mm brackets. Turns out you can order them with specific brackets:

Installing Stohr paddle shifters

feeds@yuku.com (NASA racer) — Wed, 07 Jan 2009 20:56:12 GMT

So my car had a shift lever that I found extremely awkward. Not because it was on the left (used to that) but the shape and position was just something I didn't think I could work with. So I talked to Stohr and purchased their latest paddle-shift kit but with all the R1 brackets.

Awesomely simple and clean device. I have to drill two holes for the paddle position (for me) and that's it. Should take 15 minutes to install and a few minutes to adjust. I'll post that when I...

Stohr Owner's Manul Addendum - 1st Draft

feeds@yuku.com (Jake Latham) — Sat, 27 Dec 2008 07:15:23 GMT

All -

Put together the info from my various posts below, and a few other tidbits - like the ones Pete has mentioned, into an "Addendum" for the factory manual that Stohr produces. Hopefully will add to it as things go on.

http://www.jakelatham.com...r%20Manual%20Addendum.doc

...

What size creafoam bead seat kit should I get?

feeds@yuku.com (NASA racer) — Wed, 10 Dec 2008 17:08:59 GMT

I bought one to try and do the Radical seat and it seemed WAY too big...Pegasus makes it sound like a "medium" kit is right but is that really the correct size for a Stohr?

http://www.pegasusautorac...election.asp?Product=4525

1st-gen Stohr developments and upgrades

feeds@yuku.com (Jake Latham) — Thu, 13 Nov 2008 17:39:04 GMT

I'm sure this is an incomplete list, since not everything gets mentioned over the course of time.

Things that I know of that were upgraded/updated/changed over the life cycle of the cars, including the WF-1's:

- Stronger hubs and uprights - now done by Fast Forward - as mentioned in other threads

- Fast Forward doing brake hats as well - less material removed for better strength.

- floating rotors designed, necessary to help combat knockback...

1st-gen vs WF-1 Stohr differences

feeds@yuku.com (Jake Latham) — Thu, 13 Nov 2008 17:34:25 GMT

There is surprisingly little different between the WF-1 and 1st-gen cars. Notably, the WF-1 body will fit on a 1st-gen car with a little work. This is all I could come up with casually looking at a pair of WF-1's at Rilltech:

WF-1:
1.) has lower bellcrank mounts to accept the updated shape of the cooler intakes
2.) front control arm mounts updated to two bolts on ally "shear plate" instead of steel tab on chassis, like the FB's they...

Stohrs and HANS devices

feeds@yuku.com (Jake Latham) — Thu, 13 Nov 2008 17:29:28 GMT

Some information/issues relating to fitting a HANS in the Stohr:

HANS Angle: The Stohr is more reclined than the Radical. Most can still use the 30* version, although a few have reported using a 40 in their car.

Harness Belt Spacing: The Stohr was designed with harness mount points that are quite a ways apart - maybe a foot or so. This is no good for HANS usage.

The only solution I could find was to install a harness bar....

Common Stohr Problems

feeds@yuku.com (Jake Latham) — Thu, 13 Nov 2008 17:23:47 GMT

There only seem to be a few of these, but here's what I've uncovered so far. These have been rectified in newer cars:

- "keyed" diff carrier: This is where the outputs from the diff are square keyways, instead of splines. The keys eventually crack and break, usually on the LHS of the car. Replacement parts are available for both sides.

- Rear lower control arms - These can break right near where the pushrod mount was welded on. The fix is new...

Stohr Setup Information

feeds@yuku.com (Jake Latham) — Thu, 13 Nov 2008 17:18:12 GMT

So, here's a dump of everything I've been told so far on setting up a Stohr to go quickly:

Tires: Hoosier or Goodyear. 20x8F, 22x10x13 rear. Can get away with R160 most of the time, except perhaps outside front on hot days and certain tracks (i.e. Road America). Substitute 20x7.5F for Hoosiers, and R25.

Pressures: Approx 14 cold, 18-19 hot. More gets somewhat slidy.

Springs (with tunnels): Current thinking is approx 1200# front, and rears...