Roadracer's #997 build

[j33ptj]

The event had a professional photographer there and was taking some very nice photos - here are some of the car. These are just lo-res screenshots but I'll be buying some of these from him for just $5 each. It's so rare to see photos of these cornering at speed.

Attachment 149739 Attachment 149740 Attachment 149741 Attachment 149742 Attachment 149743 Attachment 149744 Attachment 149745

The fourth one has me studying the camber.. it sure looks like it gets into some positive camber states. I'm going to dial some more static camber in before the next event...and I think raise it a little more at the rear.. that roll at speed looks very close to scrubbing tire at the rear.

Anyone played with an anti-roll bar on these?

Toms 33 build thread has some pictures of a front roll bar, post #538 has a good one.

[RoadRacer]

Raised the rear spring cups up another 1/2" or so - 5 turns - to give me some more body clearance over bumps and autocross rolling. It's finally now touching the spring on full droop, and compressed it 2 turns.

I'm really not a fan of using the stiff springs to control roll too, so I'm talking to VPM about their anti-roll bars ("sway bars" seems common here). Having a front/rear bar will allow for much easier adjustment of under/oversteer - or at least that's the way I've always done it, so it's what I prefer. Plus having anti-roll bars could allow me to lower the spring rates eventually (but I do like the car to be low, so we'll see). They've sent me drawings of their 3link bar and the roadster front bar for me to measure against. Also looking at Jegs, ElephantRacing, etc to see what's out there.

I asked FFR if they had any plans for anti-roll bars and they said "We do not manufacture or have plans to do one for the Hot Rod, most customers can accomplish their suspension tuning with spring rates, shock adjustments and alignment specs." which is fair enough.

For now, I'll do exactly that.. I was quite severely pushing at autocross, so I'll be adding more front camber/caster to help with that.

BTW, I found a great summary of Understeer / Oversteer Tuning that you might like to bookmark.

[RoadRacer]

Toms 33 build thread has some pictures of a front roll bar, post #538 has a good one.

Yeah, thanks, that looks like Dr Ruths. That's a backup option but not a fan of all the billet, or the price..

[RoadRacer]

Looking at my wheels this morning, was going to do another alignment, but had one of those ah-ha moments which took me in a different direction.

I realized that my wheels/tires were never planned - they were just a lucky buy from craigslist - $500 for 4 GT500 wheels and tires was a ridiculous steal. So I threw them on and they fit, so I've been using them. The rear wheels I want (19x13, 345x35 R19) are just so expensive that I'll be sticking with these for a while.

Anyway.. these are great but I realized I never measured the offset or estimated the scrub radius. I wonder how far out they are from "ideal"? No idea, and it's hard to measure accurately. But the manual does list some backspacing/offsets for different size wheels, and one of them is a nominal 10" wide, like mine (11" in real life). They quote 5.5" backspace with their 10" wheel. I have 7.25" backspace with mine. That's nearly 2" different.. quite a lot. That won't be helping with my tramlining (for want of a better word).

So I ordered some 1" spacers as an experiment. Increasing the front track 2" will also aid in front grip, giving me more oversteer, which is what I'm moving towards anyway. And the front is already 6" narrower than the front. So we'll see - maybe it'll help with the dynamics and not look too bad. We'll see..

[RoadRacer]

Just dropping this here.. it's properly titled, plated, and legal! Almost exactly 5 months to get to this point! I submitted my first batch of paperwork on Feb 9

2021-06-30 17.30.47-1.jpg

[RoadRacer]

Looking at my wheels this morning, was going to do another alignment, but had one of those ah-ha moments which took me in a different direction.

I realized that my wheels/tires were never planned - they were just a lucky buy from craigslist - $500 for 4 GT500 wheels and tires was a ridiculous steal. So I threw them on and they fit, so I've been using them. The rear wheels I want (19x13, 345x35 R19) are just so expensive that I'll be sticking with these for a while.

Anyway.. these are great but I realized I never measured the offset or estimated the scrub radius. I wonder how far out they are from "ideal"? No idea, and it's hard to measure accurately. But the manual does list some backspacing/offsets for different size wheels, and one of them is a nominal 10" wide, like mine (11" in real life). They quote 5.5" backspace with their 10" wheel. I have 7.25" backspace with mine. That's nearly 2" different.. quite a lot. That won't be helping with my tramlining (for want of a better word).

So I ordered some 1" spacers as an experiment. Increasing the front track 2" will also aid in front grip, giving me more oversteer, which is what I'm moving towards anyway. And the front is already 6" narrower than the front. So we'll see - maybe it'll help with the dynamics and not look too bad. We'll see..

'
Ok, fitted the 1" spacers to front wheels, giving me effectively 6.25" backspace, compared with FFR's quoted 5.5". I had a quick circuit of my favorite test route and it does seem better, but I'm doing a 3hr round trip to a cars & coffee tomorrow so I'll get a better feel then. Regardless of the scrub radius, it'll also give me more front track/grip and I'm hoping for more oversteer in the twisty bits. My next autocross is 7/25.

[RoadRacer]

I don't often post just “driving videos” from my dashcam so here's one of the recent test drive - traffic around so only got past 100 for a short burst but felt good.

[RoadRacer]

My 1" spacer experiment wasn't as positive as I'd hoped, so I did some math to see if I can work out the answer to "what is the ideal front wheel offset", while I wait for an answer from FFR. The point of all that follows is to compute where I want the scrub radius to be.. where the "KPI" will intersect the road. If it's too wrong, you will get a lot of instability and feedback through the steering on rough surfaces.

Note that I'm talking about offset not backspacing, since offset will work with any wheel width. Backspace is wheel-width specific - at least for my scrub radius purposes. Backspace is super specific if you're trying to make your wheels fit relatively to a physical constraint like a frame or suspension etc - that's not what I'm doing here. Without any bodywork I can put the wheel wherever I want.

PLEASE FEEL FREE TO TELL ME WHERE I'M WRONG! I think this all makes sense, but I'm talking to myself here

FFR provided some wheel/tire suggestions in the manual, and I'm assuming they all work well, ie the scrub radius is where they recommend.

1. 17x8, 245/40-17, 5.33" backspace, 30mm offset.
2. 18x9, 255/35-18, 5.5" backspace
3. 18x9.5, 275/35-18, 6" backspace

Given the backspace, we can calculate the offset using (backspace-0.5) - (wheel width/2):

(for a description of backspace, that strange 0.5" above (the lip) and why a 10" wheel is really 11" wide, see this article)

1. 17x8, 5.33" backspace = 24.7mm offset
2. 18x9, 5.5" backspace = 25.0mm
3. 18x9.5, 6" backspace = 25.6mm

First I noticed that FFR says 30mm offset for wheel 1, but it's really 24.7mm. A small difference, but odd.

The tire heights range from 24.7" to 25.6" so the conclusion is that if your tires are in this ballpark, you ideally want a 25mm offset wheel. Coincidentally, ~1mm per inch of tire height which is easy to remember

My front tire is taller, at 26.85", so my offset should be a bit higher (27mm) so that the scrub radius is the same. (ignoring sidewall height, tire hardness etc all affecting the ideal scrub radius)

For comparison, my original offset on the GT500 wheel was 44.5mm, and with a 1" spacer is now 19mm. It seems that I overcorrected! 44mm is too high, but I want to end up at 27mm, so only needed an 18mm spacer.

But I was +17mm out before and now only -8mm out. Honestly I'm not sure how perfect this needs to be, but I'm having fun experimenting for very little money. I do want to get it all right though, before buying some expensive wheels (my goal is still 345/35-19 rears)

[FF33rod]

You've made the assumption that FFR has made the recommendations based on scrub radius but I'd be really surprised if that's the case. I think the question they get most often is how big a tire/wheel can I put on this puppy and so the manual gives that information for each fender style. Just my interpretation... By the way, my wife calls talking to herself "talk to a smart person" you always get the best answers that way LOL

Steve

[RoadRacer]

You've made the assumption that FFR has made the recommendations based on scrub radius but I'd be really surprised if that's the case. I think the question they get most often is how big a tire/wheel can I put on this puppy and so the manual gives that information for each fender style. Just my interpretation... By the way, my wife calls talking to herself "talk to a smart person" you always get the best answers that way LOL

Steve

haha Steve, yes! I totally get your POV, and I'm sure that's a big part of it. We all want a certain look. But I still give FFR props for engineering a good car. I do wish that they would share this kind of info though - for it seems there are a lot who would like real technical info; KPI and corresponding graphs of tire height ve offset, bump steer tracings, etc. I beleive that very few change the suspension setup, so it wouldn't be wasted effort and it would make everyone's cars drive better, which in turn is better marketing for them. ¯\_(ツ)_/¯

I was surprised by the interest in my car at autocross - everyone was all over it, and everyone was watching (no pressure)!

[j33ptj]

I didn't know what scrub circles etc were so googled it and came across this;

https://www.racingaspirations.com/ap...ry-calculator/

Maybe of use, not sure how much of it can be modified to make it a HR33 specific calculation, the app seems more flexible on my iPad...

Robert

[RoadRacer]

Thanks Robert, yes I’ve seen that. The problem with all these things is measuring what you have, accurately. During building it would have been easier! Still I suppose I could create a jig one rainy weekend to measure all the pivot points.

[RoadRacer]

FYI, I received a reply from FFR regarding the designed offset/tire diameter data - they just sent me those same pages from the manual that I referenced earlier "’33 Hot Rod Wheel and Tire Recommendations", so I'm going to assume they consider their design protected IP.

Which is fair enough.. if anyone cared enough, they could measure and/or calculate it.

[RoadRacer]

Had my second autocross today - car ran much better, with way less understeer. The biggest problem is officially me. I had an experienced co-driver share my car today, and he was 2s quicker than me, in my own car

All my experience is on track, and although I can visualize the best lines around circuits, it's harder than I imagined to visualize the best lines around a parking lot with cones! Hopefully more seat time will help.

The funny thing was watching his runs on video vs mine - he seemed to be going much slower, much less drama. There was one section that I was always either very loose - or flatout spinning. He was taking an imaginary line that had no little relation to the cones. All this makes perfect sense intellectually, but not when the red mist descended. Fun stuff.

[RoadRacer]

Doing yet another alignment - seems I do one once a month! Adjusted toe some more, but left everything else the same. Always playing..

Biggest thing is getting close to buying my "real" wheels. Searching on 19x13 (really 14" wide) like these Forgestars with 345x35R19 Bridgestone Scuderia tires. These will give me 1.7" more rake and 3" more tire on the road.

Noone seems to sell 19x13 except for vipers with their 6x114.3 bolt pattern, but I need 2" spacers anyway, so I'll get 2" adapters

These wheels are +62mm (2.44") offset, so backspace is 9.44", compared with my current 7.25". With 2" adapters, I'll only go inwards 0.2" - plenty of room.

[RoadRacer]

Did my third autocross today.. here’s my best run. Still way off the pace - and it’s still all me, not the car. It’s amazing how hard autocross is to get good at. So much fun!

[FF33rod]

Off pace? wow, that looked great to me!

Steve

[RoadRacer]

I keep coming back to weight transfer and the lack of sway bars.. especially every time I get photos from autocross that show the car rolling like crazy. Drives me nuts seeing this. Obviously, the weight transfer is going to happen, and this would be extreme on the street, but I just don't understand why we're not controlling it with sway bars. Even more so given the tuning capabilities of adjustable sway bars... and there's no downside to sway bars that I know of, except for maybe packaging - but there seem to be room.

Look at these:

roll1.jpg roll2.jpg roll3.jpg roll4.jpg roll5.jpg

I was speaking to folks at the track yesterday and most of them recommended mocking something up with PVC pipe etc, and then sending the measurements to a place that can either supply parts (e.g. jegs) or can bend bars to spec. I know Bret Voelkel's Goodguys Nationals-winning 33 had great custom sway bars, but they don't have the plans.

Anyway, would love any thoughts on the pics above. Does anyone think I shouldn't add sway bars?

[HVACMAN]

I believe Dan Ruth used to sell a sway bar for the 33.

[RoadRacer]

I believe Dan Ruth used to sell a sway bar for the 33.

Yes, he did/does but I'm not a fan of that option. It doesn't seem to be adjustable, for one thing..

[J R Jones]

James, I envy the exotic rocker arm suspension you have. My 818 is encumbered with compromise resulting in at least bump steer so I have become increasingly skeptical of the design.
My catalog photo of the static Hot Rod suspension suggests a little camber gain on jounce, but I see your AX photos and positive camber in turns. What is your static camber adjustment?
Have you measured bump steer? Your (high) steering arm location makes me wonder?

In general, body roll and weight transfer is not a bad thing. We raced SCCA Showroom Stock against Saabs one season, they rolled a lot and were fast. It is advantageous on wet pavement.
Less body roll puts less emphasis on bump steer and (positive) camber gain, but does not solve it.
Your AX video did not demonstrate understeer or oversteer to me, seemed neutral. I did hear the tires a bit
The rear "appears" to roll more than the front. If you add a rear ARB it will oversteer more. If you are already oversteering, you might consider ARBs on front or both ends.

Your rocker arm suspension suggests exotic anti-roll devices to my creative mind. Conventional ARB can be adjustable with arm length link mount holes or a sliding yoke.
Splined bars are more easily swapped for diameter. Hollow bars are good.

https://ast-suspension.com/docs/tech...i-Roll-Bar.pdf

BTW your AX driving style could be likened to a lumberjack, swinging an AX, not chain sawing. Stabbing and lifting work on fast large turns, but limited throttle modulation as a compromise through slaloms is better.
Perhaps you are OC about the body roll. Let it roll, but manage the fore/aft weight transfers with controlled throttle and brake.
jim

[RoadRacer]

My catalog photo of the static Hot Rod suspension suggests a little camber gain on jounce, but I see your AX photos and positive camber in turns. What is your static camber adjustment?
Have you measured bump steer? Your (high) steering arm location makes me wonder?

This is all a stock FFR33 setup. Right now I'm at -0.5º static, with 8º caster. Of course roll is affecting the camber too.. one of many reasons I'd like to limit it.

As for bump steer, I have a kit to correct it, but have never found the time to fit it.

BTW your AX driving style could be likened to a lumberjack, swinging an AX, not chain sawing. Stabbing and lifting work on fast large turns, but limited throttle modulation as a compromise through slaloms is better.

Ha, yes! It's the most bizarre thing - from me being super smooth on circuits and giving people that same advice, all I do in autox is overreact. I find autox to be like taking a whole F1 race and speeding up the footage until it fits into 40s. I've been going quicker every lap so far by driving slower. Yesterday that was both my most calm and fastest autox run.. so you can imagine how the earlier ones went.

[J R Jones]

James, I know exactly what you are stating. The tight course and cones are information overload. It takes a discipline to focus further out, and let muscle memory handle the stuff inches away. Maybe blinders are not just for horses.
I would be distracted by your exposed front tires. Too interesting to see what they are doing and how they are reacting.

If you install front ARB I would run back to back complete, and with one link disconnected.
I do not know how you adjust camber, but I would try -1.5 to -2.0.
Cam on the LCA? Maybe you could mark the adjuster and go back and forth on that too.
jim

[J R Jones]

James, I raced with Paul Newman a couple of times. He was very good, and benefited from introspection.
He recognized early on that he had a death grip on the steering wheel. He consciously adopted a loose grip and a calmer attitude.
He did not mention it but I think breath control helps too.
jim

[CraigS]

I am coming into this thread late so a few thoughts as I start at the beginning. Offset; Over the years I have had a bunch of combinations and none seemed too terrible except one w/ a ton of it. Note that front wheel drive cars run very close to zero scrub radius because w/ more offset the power going to the ground tries to steer the car. In perfect conditions the one side offsets the other side. But as soon as traction varies left to right, the tire w/ more traction will try to steer to the opposite side of the car which the driver has to fight against. I think you have it here;
"But I was +17mm out before and now only -8mm out. Honestly I'm not sure how perfect this needs to be, but I'm having fun experimenting for very little money."
Roll; I agree you have WAY too much. I couldn't find specs for the springs, and even if I did that would be just spring rate vs wheel rate which is what really matters. But, since bars seem to be hard to do, you could increase spring rate. I like Eibachs but actually use the QA1 Hi Travel springs as they are less expensive. I'd think about almost doubling whatever the stock spring is. (data point = roadsters had 450 or 500 fronts and I run 800). Do the fronts first. Don't worry about the usual thought that stiffer reduces grip so changing the fronts only will cause understeer. It can also reduce roll so much that it reduces camber loss which will reduce understeer. And more F spring will; reduce dive under braking and; make the car feel more responsive to steering input. I see you are really thinking about fine points that many don't even know about so I bet 2 yrs from now you will have tried 3-4 sets of springs.
Camber; affects tire grip. Anything up to about 3.5 maybe 4.0 deg negative increases grip. So, for instance, say the stiffer springs do cause too much understeer, leave the springs and crank in more camber. Think like this. If your car has perfect handling balance w/ F and R camber at -1.0, you could change it to F and R = -3.0 and the handling balance would be the same but the overall grip level would be higher.
Bump steer; You have to measure it before you change it. My method is easy and inexpensive. You need a laser (one w/ a magnet is nice) and a 90 degree angle bracket, and a couple of clamps.
IMG_20130428_162158_880 by craig stuard, on Flickr
I run a ratchet strap through the steering wheel spokes to lock it down. I shoot the laser sideways because, if you shoot it towards the front, the wheel actually moves in and out a little as it goes through it's travel which could be mistaken for toe change. I remove one of the coil over mount bolts so the spindle can easily be moved through it's range. A dot laser is a little easier but I had a line laser so I used the level to orient the line vertical so I could easily see movement. Don't worry about needing to read small movement. This was an old MkII roadster and it started out w/ the laser moving nearly three inches. The best I ever got it was about 1/2 inch. BTW, if you have a choice you want toe out in bump and toe in in droop. Toe out in bump means the heavily loaded outside tire will steer a little less than you expect which is much easier to deal w/ than getting more steering than you wanted.
Driving in AX; This will get easier as you do more of it. JR mentioned a steady gas in slaloms. 100% agree. If you are on and off the gas, the car rocks forward and back, transfers weight forward and back, and that messes up your cornering. As you walk the course, at every slalom count steps from cone to cone. Nothing special, just walk like you always do. They are usually around 30 of my steps. What you want to know is does the length between cones change. If it does you have to adapt that steady gas. This will get easier w/ more seat time but you need to be thinking at least one turn ahead. A quick example; imagine a 4 cone slalom that is followed by another 4 cone slalom and they are both in the same direction and they are both a little faster than usual and there is a 100ft gap between the 2 slaloms. But the second slalom is offset by 50 ft from the first. So you hold that steady throttle through the first 4 cones and it feels great. But now you have only 100ft to move 50ft sideways. It is easy to tell the experienced from the novices. The novices try to make that jog, realize they are too fast and their entrance into that second slalom is an oohhhh craaaap, oh, oh, OK I made it. The experienced drivers eased out of the gas a little early at the end of the first slalom, made the jog, and were back on the gas as they passed the first cone in the second slalom. I hope you stick w/ it because AXs can be super rewarding and it may never come up, but I have had 4 or 5 situations on the road where my AX experience absolutely saved the day. 2 of them my wife was w/ me and I will never forget her comment after the second one. We got maybe 1/4 mile beyond the problem and she turns to me and asks, how the he11 did you do that? I said, I guess all those AXs paid off.

[RoadRacer]

Roll; I agree you have WAY too much. I couldn't find specs for the springs, and even if I did that would be just spring rate vs wheel rate which is what really matters. But, since bars seem to be hard to do, you could increase spring rate. I like Eibachs but actually use the QA1 Hi Travel springs as they are less expensive. I'd think about almost doubling whatever the stock spring is. (data point = roadsters had 450 or 500 fronts and I run 800). Do the fronts first. Don't worry about the usual thought that stiffer reduces grip so changing the fronts only will cause understeer. It can also reduce roll so much that it reduces camber loss which will reduce understeer. And more F spring will; reduce dive under braking and; make the car feel more responsive to steering input.

Thanks Craig, this is great feedback. Stiffer springs are needed at the back already. Once I have at least one sway bar I'll play with springs. VPM may be the easiest answer for the rear sway bar - they have a roadster 3 link setup that I'm hoping I can modify to my car (also 3 link). They've been super helpful.

Camber; affects tire grip. Anything up to about 3.5 maybe 4.0 deg negative increases grip. So, for instance, say the stiffer springs do cause too much understeer, leave the springs and crank in more camber. Think like this. If your car has perfect handling balance w/ F and R camber at -1.0, you could change it to F and R = -3.0 and the handling balance would be the same but the overall grip level would be higher.

Yes.. at least for now I'll be dialing in WAY more static camber for the next event. I was hoping that the high caster would be giving me sufficient camber when turning, but the photos show that didn't work as well as I'd hoped.

Driving in AX; This will get easier as you do more of it. JR mentioned a steady gas in slaloms. 100% agree. If you are on and off the gas, the car rocks forward and back, transfers weight forward and back, and that messes up your cornering. This will get easier w/ more seat time but you need to be thinking at least one turn ahead.

As you say, I'll get better quickly as I do more events. The first couple I was way too confident, went sideways through most corners and was overcooking everything. I'm calming down and getting better at 'seeing' the imaginary line - and more importantly, I'm getting better at remembering it when driving!

Thanks again, this is priceless advice.

[J R Jones]

James/Craig, I expect you have read the data guy NAZ. In another thread we discussed suspension and he knew the UCA rocker ratio to be 1.37:1. That number can identify your wheel rate.
https://thefactoryfiveforum.com/show...k-Spring-Rates

Caveat here, that included a discussion about harsh ride characteristics and spring and shock rates for you to anticipate the compromises.
NAZ customized a Mustang/Pinto kit for bump steer.
BTW Craig, some Hot Rod guys are running 8* caster, and as you have noted, that is a challenge in AX without power steering. I do not know if James' SBC is cast iron or aluminum (weight)

Here is a concept: If your UCA had a lateral range of pivot points, you could adjust wheel rate without changing the spring/shock.
jim

[RoadRacer]

James/Craig, I expect you have read the data guy NAZ. In another thread we discussed suspension and he knew the UCA rocker ratio to be 1.37:1. That number can identify your wheel rate.
https://thefactoryfiveforum.com/show...k-Spring-Rates

Caveat here, that included a discussion about harsh ride characteristics and spring and shock rates for you to anticipate the compromises.
NAZ customized a Mustang/Pinto kit for bump steer.
BTW Craig, some Hot Rod guys are running 8* caster, and as you have noted, that is a challenge in AX without power steering. I do not know if James' SBC is cast iron or aluminum (weight)

Here is a concept: If your UCA had a lateral range of pivot points, you could adjust wheel rate without changing the spring/shock.
jim

Jim, the recommended caster is 4º for manual steering and 8º for power. I'm running an unusually high caster (on purpose), but this is not normal, FYI. I have a good ol heavy cast iron block and heads

[J R Jones]

James, So not the LS engine, more like the LB engine.
I have a fresh 1968 Corvette 300hp 327 for sale (13K miles) and cannot get any offers. Everyone wants non-ferrous.
Craig made an interesting observation that high caster lifts the car on the inside and drops the car on the outside, contributing to the effort.
jim

327 left.jpg

[CraigS]

Yep -camber gain via caster is a nice thing to have but it's effect is limited. Unless a car is grossly understeering, the steering is turned so little that the gain is only on turn entry. Notes on judging handling balance. It is best done in a longer duration turn so that you can separate out the turn entry part and concentrate on what is happening in the middle of the turn w/ just enough gas to maintain speed. Different courses can require a different balance. Slaloms are faster w/ slight understeer, tight turns are usually faster w/ a less understeer, so how many of each type turn does today's course have. If one thinks his car is understeering, be sure it isn't caused by an overly aggressive bonzai turn entry. If you are having trouble in turn X, ask others how their car is doing in turn X. If everyone's car is pushing in turn X it may be the surface, or surface camber, so change how you drive it rather than change the car.

[J R Jones]

I'll take this opportunity to pontificate on another geometric influence...Akerman.
Akerman is the configuration of the steering arms and the wheelbase to turn the inner wheel more than the outer wheel and therefore match the turn radius. In street cars this minimizes tire squeal in tight turns.
Back in the day the racing wisdom was that with small turning angles and power-drift/oversteer, Akerman was not advantageous. I took it out of my BP Shelby, but I could not identify a difference (season to season).
https://en.wikipedia.org/wiki/Ackerm...ering_geometry

The tight turning radius of AX brings questions to mind:
Is Akerman advantageous?
What if the is Akerman appropriate for the donor car? Too much, too little?
Does Akerman reduce understeer?
Does Akerman hinder understeer (high slip angle) recovery?

Of all the modifications one can do for performance, I think changing Akerman is at the bottom of the list. Perhaps too much Akerman would raise it a couple of places.
jim

[RoadRacer]

I spent a few minutes under the car last night trying to think in 3 dimensions and came to the conclusion that with minor modifications I can fit the VPM 3-link sway bar. It's built for the roadster 3-link, but the measurements seem the same - and critically will work around my banana bracket. I just placed an order, so we'll see how it goes - I'll obviously post pics here.

3-link34d.jpeg

[J R Jones]

James, Nice hardware, appropriate diameter and adjustable hardware.
It looks like a rear bar for a live axle?
Looks like there may be a short cut mount scheme to do a quick evaluation.
jim

[RoadRacer]

James, Nice hardware, appropriate diameter and adjustable hardware.
It looks like a rear bar for a live axle?
Looks like there may be a short cut mount scheme to do a quick evaluation.
jim

Yep, exactly. It's formulated for the Cobra 3-link which looks almost identical to the 3-link under the hotrod, so fingers crossed.

[j33ptj]

Is this for the rear or the front?

[RoadRacer]

Is this for the rear or the front?

The rear. It’s not ideal to start with the rear, or have only one bar, but it looks an easy mod and I can start on full soft to limit the oversteer.. and I’m also planning wider stickier rear tires so that will counteract the oversteer. Getting the roll under some control is my #1 focus.

[CraigS]

The VPM bar is definitely a nice piece. I made mine easily adjustable. The bolt that goes through the aluminum sliding block got a fender washer tack welded under the head. A portion of the washer was bent over the edge of the al block so the bolt wouldn't turn. I lay down beside the rear wheel and reached in w/ a gear wrench to loosen the nut. Slide the block an inch, and tighten the nut. Do the same on the other side. I kept the gear wrench wrapped up in a bath towel I stuffed behind the seat. I could lay on the towel and adjust the bar in maybe 3 minutes between AX runs. As you assemble the rod end to the block stick a small o-ring on one side of the rod end. The block will clamp tight on the bar but there may be a small amount of play where the rod end can slide around on the bolt. You would be surprised how much racket .010 inch of play makes in normal driving.

[RoadRacer]

Thanks Craig, good tips.

[RoadRacer]

Today’s experiment is to trade straight line stability for fast corners. I’ve been running high caster to help on high speed bumpy/wavy roads, but obviously it resists cornering. Tonight I wound caster back to 3.5deg to see how it feels.. yes definitely lighter steering but cornering much improved. I need to put more miles on it this week but wanted to make this change before the rear sway bar comes, so I’m not changing too much at once.

There are a couple of long sweeping ~75mph corners near me that I’m convinced the car could do at 90 with the right setup. Forever learning!

[33fromSD]

Today’s experiment is to trade straight line stability for fast corners. I’ve been running high caster to help on high speed bumpy/wavy roads, but obviously it resists cornering. Tonight I wound caster back to 3.5deg to see how it feels.. yes definitely lighter steering but cornering much improved. I need to put more miles on it this week but wanted to make this change before the rear sway bar comes, so I’m not changing too much at once.

There are a couple of long sweeping ~75mph corners near me that I’m convinced the car could do at 90 with the right setup. Forever learning!

Hi James

Just curious, did you leave camber at -.5 deg as you had it set originally or did you tweak that slightly too?

Jim