Roadracer's #997 build

[RoadRacer]

Left that the same Jim. I try to change just one thing each time.

[33fromSD]

Left that the same Jim. I try to change just one thing each time.

Sounds good, I think -.5 deg is the sweet spot anyways

Jim

[RoadRacer]

Good day today.. got the VPM rear sway bar almost installed.

Bolting it up to the 3 link rear was easy, and a perfect fit. And yes it does fit without touching anything.. but it's close!

rear sway.jpg rear sway 2.jpg rear ps sway.jpg rear ds sway.jpg

I decided to attach the end link to the upper shock mount, so I made up a bracket to fit. Note that these pics are all at full droop.. I'll post more when I'm back at ride height tomorrow, and that's when I'll do final fit. The bar is obviously adjustable, and I still might want a longer end link (easy at speedway)

sway bar bracket.jpg trial fit at full droop.jpg

For the eagle-eyed amongst you, while I was in there I removed my shocks and added another bump stop.

[RoadRacer]

Here are the sway bars as I drove it this morning. I'm considering whether I want to keep as-is, with the end link ~90º to the sway bar, or to get a longer end link and have the sway bar more horizontal. Given the cheapness of the speedway links, I'm leaning (no pun intended) towards getting 7" bars (2" longer) as a compromise - and it'll give a little more clearance around the banana brace and shocks.

This is at about the "half stiffness" setting.

sway bar ride height pass.jpg sway bar ride height driv.jpg

I drove pretty steadily this morning, just to make sure it all "worked", no rubbing etc, so didn't go over 90mph . I already think the double bump-stops should be mandatory on these cars though.. rode much better over my big dip roads.

[J R Jones]

James, changing to longer links is an aesthetic decision, it does not change performance. Sliding in or out on the ARB arms will have a big influence. Likely adjustments are easier with the arms flat.
If you have a digital angle/level and a big flat expanse of pavement, you could measure body roll at fixed speed and turn radius, like a skid pad.
You could also put tie wrap indicators on the rear shock rods and measure difference after turning hard in one direction.
In the end I predict the magnitude of oversteer will determine your set-up.
jim

[RoadRacer]

James, changing to longer links is an aesthetic decision, it does not change performance. Sliding in or out on the ARB arms will have a big influence. Likely adjustments are easier with the arms flat.
If you have a digital angle/level and a big flat expanse of pavement, you could measure body roll at fixed speed and turn radius, like a skid pad.
You could also put tie wrap indicators on the rear shock rods and measure difference after turning hard in one direction.
In the end I predict the magnitude of oversteer will determine your set-up.
jim

Yes some aesthetic but it will also move away from the shock adjustment collar and banana bracket. I expect to run quite stiff (ie short bar) so I think I may need some extra length to do that.

[RoadRacer]

BTW, for those building a 33 with a TKO600.. don't use the "obvious" driver's side speedo sensor. Buy this pigtail and use it on the passenger side.

I used all the parts I got from Fortes, with the funny plastic gear, and it broke somehow within a few thousand miles. The speedo started registering only 0 or 80mph. I just switched to the other side, and now it's steady as a rock. I had no idea there were two speed takeoffs until I asked FFR about this issue.

This is the one NOT to use..

image007.jpeg

[HVACMAN]

Good day today.. got the VPM rear sway bar almost installed.

Bolting it up to the 3 link rear was easy, and a perfect fit. And yes it does fit without touching anything.. but it's close!

rear sway.jpg rear sway 2.jpg rear ps sway.jpg rear ds sway.jpg

I decided to attach the end link to the upper shock mount, so I made up a bracket to fit. Note that these pics are all at full droop.. I'll post more when I'm back at ride height tomorrow, and that's when I'll do final fit. The bar is obviously adjustable, and I still might want a longer end link (easy at speedway)

sway bar bracket.jpg trial fit at full droop.jpg

For the eagle-eyed amongst you, while I was in there I removed my shocks and added another bump stop.

It appears this should fit a four link set up too. Maybe??

[RoadRacer]

From my understanding of a four link, yes. But feel free to post pics here. 3 link is more complex with the banana brace and panhard bar framework - but you have none of that right? So it’ll fit for you but it will be asymmetrical. Not a problem functionally though.

[RoadRacer]

Omg the car handled amazingly at the track today. Did a Track Night in America event at Harris Hill south of Austin and it’s a great track. The car performed flawlessly. Very neutral handling.. as the (old) tires lost grip at end of each session it was still just drifting rather than under/over steering. Very happy.

The sway bar and extra camber (1.4deg) worked great. I’ll wait on the photos but the roll seemed more under control.

One of the faster cars and was catching and overtaking each session. Stock Brakes even held up for each 15-20min session.

One weird thing.. on the procession lap my friend was behind me and said the my “rear wheel was wobbling all over the place” - bear in mind I’m many miles on this now - and I felt nothing. Anyway I jacked it up, used my growler as a reference and spun the wheel.. yep it’s 1/4” out of true! I bought rear end from junkyard and wheels from Craigslist so one of those two things got bent somehow before I got them. I still did the event and will look into this at weekend. So odd though..

[RoadRacer]

We’ll I swapped a front and rear wheel.. and it has the same 1/4” wobble! So.. and I know little about solid rears.. I guess it’s an axle (what I’d call a driveshaft but that’s used differently here) that’s bent? Is that common from curbing for example?

I did get it literally from a junkyard..

Sounds like a pain to fix?

[33fromSD]

We’ll I swapped a front and rear wheel.. and it has the same 1/4” wobble! So.. and I know little about solid rears.. I guess it’s an axle (what I’d call a driveshaft but that’s used differently here) that’s bent? Is that common from curbing for example?

I did get it literally from a junkyard..

Sounds like a pain to fix?

Not too hard to fix at all.

1) Remove your caliper & rotor
2) Drain differential and remove the differential cover
3) on the 3rd member there is a large cross pin held in by lock bolt (I've attached a pic showing where those are)
4) Spin the ring gear enough to see the ends of the axle shaft & remove the C-clip from the end of the axle shaft (there may be a rubber o-ring holding in the clip (some had them, some didn't)
5) Slide out old axle
6) As long as the axle is removed I would replace the seal at the end of the rear end
7) carefully slide in the new axle and reverse steps 5 to 1

Pretty straight forward (couple hour job) and with running it pretty hard on the track as you have been, you now get new fresh gear oil too.

Pic of Differential Cross Pin & locking bolt
fullsizeoutput_6a.jpeg

Jim

[33fromSD]

By the way, "if" you left the ABS sensor on when you got the rear end from the junk yard, you'll need to remove that ABS sensor so you can push the axle in slightly to remove the c-clip. The c-clip just slides into a groove machined into the end of the axle

Jim

[RoadRacer]

Thanks Jim, yeah I did take it apart when I bought it, to clean/paint etc so I've done it once. Handy steps though. The rest of my racing life has been IRS or transaxles. ¯\_(ツ)_/¯

So, should I go to local parts store and get a straight replacement? I never thought I needed anything special for a light car and ~300hp..

Another dumb question, but I'll ask anyway(!) - I don't need to buy a set, do I?

Befor I do anything though, I'm going to rule out the rotor being the problem, I realized overnight that it's conceivable the wobble could be there too.

[sread]

Hey James - I'm a little surprised the hotrod would pass tech for a track day. No issues on that? I assume there are pretty structured rules for passing. How are different cars grouped together for the sessions?
I have done many track days on motorcycles at most of the Texas tracks but never made it to Harris Hill - I had heard it has gotten pretty rough the last few years.

[33fromSD]

Thanks Jim, yeah I did take it apart when I bought it, to clean/paint etc so I've done it once. Handy steps though. The rest of my racing life has been IRS or transaxles. ¯\_(ツ)_/¯

So, should I go to local parts store and get a straight replacement? I never thought I needed anything special for a light car and ~300hp..

Another dumb question, but I'll ask anyway(!) - I don't need to buy a set, do I?

Befor I do anything though, I'm going to rule out the rotor being the problem, I realized overnight that it's conceivable the wobble could be there too.

If it turns out you confirm it's a bent axle, personally, I'd go with a set. You wouldn't necessarily have to though. Local parts store may have one, worst case they need to order it and it will take a couple days to get. If your going to replace the set then knowing you track it, you may want to look online for a set which is a little stronger from someone like Moser or Curry, etc.. Not cheap though.

You can even get sets that eliminate the need for the C-Clip.

Good luck

Jim

[Big-boss]

I would go with anew set...One of the cheaper things you will buy...Aftermarket as well...They are old and they were in a heavier car...But you are doing more to them than what they were designed to do...Have you ever seem one break? It makes for a real bad day...

[RoadRacer]

Hey James - I'm a little surprised the hotrod would pass tech for a track day. No issues on that? I assume there are pretty structured rules for passing. How are different cars grouped together for the sessions?
I have done many track days on motorcycles at most of the Texas tracks but never made it to Harris Hill - I had heard it has gotten pretty rough the last few years.

Never had any problem at autocross or this TNIA. This one was “fill in a form” - no one looked at my car. But the only thing I’d ever worry about was the roof. Does it qualify as a roof? Debatable. But no one has yet questioned me on that.

Harris hill is one of the best “amateur” tracks I’ve been on.. and I did a lot in Europe. They resurfaced last year, and they have some technical corners that a lot of people were doing wrong!

I ran with the novice pack and it was strictly point2pass in 3 zones. Two higher classes for those who’d been before. TNIA is of course much lower key - not racing, not even timed. But we were still able to get good sessions in. We had 3 or 4 20min sessions.

[RoadRacer]

I would go with anew set...One of the cheaper things you will buy...Aftermarket as well...They are old and they were in a heavier car...But you are doing more to them than what they were designed to do...Have you ever seem one break? It makes for a real bad day...

Thanks. No the closest to seeing one break was my GT40 at Barcelona Catalunya circuit. After the sessions were over my friend and I decided to drag race the straight while no one was watching. He had a caterham seven. He would always beat me on corners and I’d roar past him on straights, but we had no idea who would win a drag race. But we never found out.. my hot sticky 335’s snapped my drive shaft on launch.

It was weird making all the right noises but not moving at all..

The best part was I got a free week in swanky hotel in Barcelona while the RAC flew down a replacement driveshaft for me to fit. Holiday insurance is the best

[RoadRacer]

I had a slight problem with the sway bar, which requires some tuning

I was going to check it out this weekend and tighten everything up, but I was too slow by a day.

Yesterday on my last trip home I stopped into a store that had a sloping driveway, and as I turned in (slowly) obviously the inside and outside of the car are getting quite different loads.. and I heard a bang. I stopped in the parking lot thinking the tire or wheel or drove over something but it drove ok and I saw nothing so didn't look too hard.

This morning I walk past the garage and WTF..

tilted.jpg

Not the greatest picture, but the passenger side is 2-3" higher than the driver's side. Uh-oh.

Underneath I can see why..

sway bar spun.jpg

The sway bar has spun on the rear end, and is now hard against the shock and the banana brace. It's also moved sideways an inch or so inside the bushing. All things I was concerned about when I saw the sway bar, but now I know. I'm no welder, so I'll brainstorm how to stop that spinning some other way. Going side-to-side I can stop by adding some bushings on either side. For now, I'll reset into position and tighten things up some more.. and pay more attention to loud noises...

I know this is a roadster part, so I'm curious if any owners have already seen this and have their own fixes?

[J R Jones]

James, I was fascinated by your comment yesterday about racing a GT40. We built and raced a GT40 MKIV in vintage for several years, 427 side oiler and all. pic attached
As GT40s have a transaxle, you broke an input shaft or an axle shaft? I assume axle.

I was not overwhelmed with your ARB mount design. Similar to muffler clamps for attachment. A welded solution is most appropriate.
A somewhat more robust solution would be a clamping collar that could be welded off-car with a ARB mount.
https://www.amazon.com/Climax-2C-300...ustrial&sr=1-8

Not likely that you will find the appropriate ID.

As I mentioned previously you might consider attaching the ARB legs to your lower track bars, but that would sacrifice adjustability.
If you go the fabricate/weld route, disconnect the battery and ground the axle housing to avoid "sparking" through the axle bearings.
jim

GT40 rides.jpg

[RoadRacer]

Yes Jim, that was just how the sway bar came. Plenty of room for modification

And to be clear, my GT40 wasn't real.. a replica. I'm not rich . But I did 60,000 miles and most of the big-name European circuits with it.

[J R Jones]

James, Who's GT40 replica was yours?
I see a Mexican team ran an RCR GT40 replica in La Carrera Pan America last year and twisted the chassis. They are entered again this year.
We ran LCPA a few years ago in a 1954 Corvette re-creation of an original racer.
That is a long tough race, especially in an open two seat roadster.
jim

lunch stop in LaCarrera.jpg

[RoadRacer]

James, Who's GT40 replica was yours?
I see a Mexican team ran an RCR GT40 replica in La Carrera Pan America last year and twisted the chassis. They are entered again this year.
We ran LCPA a few years ago in a 1954 Corvette re-creation of an original racer.
That is a long tough race, especially in an open two seat roadster.
jim

lunch stop in LaCarrera.jpg

The best in the mid 90's was GT Developments ("GTD") in Poole, UK. That's what I had.. a spaceframe but worked well.

image0000127A.jpg image0000124A.jpg image0000114A.jpg image0000070A.jpg image0000072A.jpg

[RoadRacer]

Couple ideas about the sway bar. I'm not a fan of the 3/8-24 u-bolt since that can only be torqued to 25-30lbs, doesn't seem much clamping force. So I'm looking at 9/16 u-bolts to replace them.

I also noticed that the lower shock mount is right alongside and almost in line, so - although far from ideal - by welding a bar or box section as shown below it would help stop rotation. I feel like it should be welded, not bolted, and that would allow a strengthening rib down it. Any other ideas come to mind? Of course, there is welding to the rear end directly, but then they'd have to know what they were doing..

sway_bar_brace.png

[J R Jones]

James, As I mentioned welded brackets are preferred.
A clamp-on alternative might be to have four clamp blocks machined using your current saddle clamp as a pattern. You could double them up, replacing the "U" bolt and clamp them together with conventional grade 5 bolts. The increased surface area and clamp load might stay in place. 6061 aluminum would be appropriate.
jim

[RoadRacer]

ordered my new axle shafts.. should have them in 10-14 days. Fingers crossed.

Here's a video of the fastest lap I did at the local Harris Hill track near Kyle. My first time there, and you can hear my 2016 and 2018 date code tires not being very happy Looking forward to using up the last bit of tread and getting something new and sticky. My local autox club put me onto this excellent article on the subject of which tire": Ultimate track tire guide | 200tw, 100tw, street-legal track and R-comps

[33fromSD]

ordered my new axle shafts.. should have them in 10-14 days. Fingers crossed.

Here's a video of the fastest lap I did at the local Harris Hill track near Kyle. My first time there, and you can hear my 2016 and 2018 date code tires not being very happy Looking forward to using up the last bit of tread and getting something new and sticky. My local autox club put me onto this excellent article on the subject of which tire": Ultimate track tire guide | 200tw, 100tw, street-legal track and R-comps

On the axle shafts James, did you stick with the OEM axles or upgrade to after market?

Jim

[RoadRacer]

I went up just a smidge Jim

https://www.jegs.com/i/Alloy-USA/013/12187/10002/-1

[33fromSD]

Nice....

Price isn't bad either considering you get the axles, lug studs and seals.

Jim

[sread]

That was great! Love to see the vids of the hot rod being driven hard. I bet you got a lot of interest in the pits - especially after seeing how well the car went.

[RoadRacer]

That was great! Love to see the vids of the hot rod being driven hard. I bet you got a lot of interest in the pits - especially after seeing how well the car went.

LOL, yes it's funny. Same at autocross. Everyone is mouths open, like WTH? I think most people don't initially realize it's a modern chassis underneath. In a sea of miatas and beemers and even vettes it kinda stands out

I'm having a blast! And in 7 months and many miles I think I've washed it once..

[RoadRacer]

Some professional photos from TNIA.. Looking at photo 5, I still need a front sway bar.. and maybe even more static camber.

90377827-INTER-43.jpeg 90377830-NOV-386.jpeg 90377829-NOV-383.jpeg 90377828-NOV-238.jpeg 90377831-NOV-473.jpeg 90377832-NOV-503.jpeg 90377833-NOV-518.jpeg

I do like the last one, as I go over the blind hill at sunset.

[RoadRacer]

BTW, I probably didn't say so, but the car drove much faster around corners than before at autocross. Just by adding rear sway bar.

You can even see the difference.

Before

roll2.jpg roll4.jpg

After

zoom-in-cornering.png

I'm leaning (lol) towards stiffer springs all around next. Then finally I'll look for front sway.

[Big-boss]

Squealing tires are Happy Tires

[RoadRacer]

After seeing how cheap springs were(!) I ordered a set.. up 40% all around. 350lbs front, 550 rear.. should be fun

[RoadRacer]

Got the front springs on yesterday.. Jegs 9", 550lb. $40 each is crazy cheap. Went straight on, you don't need to remove shocks or anything complex. ~15minutes a side.

8" would have been better, but they didn't have that option. I had to wind collar ALL the way down, was 1.8" up from the bottom, now at 0". I'm still at 5.25" ride height at the front, due to that extra inch of spring and less compression.

I already love it more, less roll, stiffer, better steering. Everything tightened up. But yes, it's not for many people. Most go lighter springs and more comfortable

2021-09-30 18.26.16.jpg

[FF33rod]

The kit came with 500s on the front didn't it? (maybe it was 400s). I went down to 220s and like it much better on the street....

Steve

[RoadRacer]

The kit came with 500s on the front didn't it? (maybe it was 400s). I went down to 220s and like it much better on the street....

Steve

yeah, standard is 400's on front, 250 on back.

I'm moving to 550, 350 (+40% both)

[RoadRacer]

Note to anyone watching.. the 9" springs would work normally, but I recommend anyone buys the 7" if going with stiffer springs. I'm having to return my 9" 350lb rears because that extra inch, plus less compression, puts the collar into very close proximity with the sway bar. So I'm going with 7" instead.