AutoX'ers THREAD

[prsrcokr]

Thanks for all the info, this is some very helpful stuff. -1.0 to 1.1 camber up front was all I could get as well, still running more rear camber (although -1.5 seems better than the -2.0 I used previously) JB weld must be stronger than I thought
Ah, you setup the Hunter for a custom model, mine always shows all red beyond Caster.
Oddly enough I had oversteer for a long time, I've never really had understeer with the car other than tires overheating. Since changing to a heavier front bar (Tanabe, ST rear) it's fairly biased toward oversteer. Maybe if I had more front camber I could run a square tire setup and still not be tail happy? (235/255 now)

Agreed on the rear ratios, I've run those three as well. I know I'm giving up for auto-x using the 3.73 but it works better for me with track stuff (less shifting, I don't go to redline on this engine)

Brian

 

[LordDigital]

JB weld was super strong ,it actually lasted 3 meters or untill the first tap on the brakes and then the arms snaped Of course the final product was overEngineered as any other experimental component on my car Hunters are great alignment racks ,but I could not get the DSP 4000 to do custom alignment (possibly becouse it is installed in a Toyota Dealer) ,the printout is actually from a DSP 400 where custom setting were easy to input.

On the over/understeer issue first of all it is subjective in a way ,IMO my car now is in mild oversteer setup but when Kirs drives it he swears that it is pretty neutral - go figure. In general the rear suspension is over complicated ,very hard to allign and I still can't claim that I understand why it was designed that way. That said from practice I found that the rear swayBar has one serious trade-Off ,yes it reduces bodyRoll but I don't know quite why - it screws up the camber when it is over tight. Look at this picture - this is with at least -1.3 rear camber and my contact pitch was a disaster. The setup was Tein RA at stiff + ST rear sway at soft and the car was oversteering in tight corners way too much. I wanted to remove the rear sway ,but decied to simply extend it with a few inches on each end (as far as the MDC endlinks would reach) and on the next autoX ,the crazy overSteeer was gone.

Now I can't theoretically quite explain this ,but it happened. Many experienced RWD autoX guyz would tell you that with the right dampers/springs you don't need the rear sway bar ,for me it is a nice thing to have because it makes the weight transfers more delayed wich is great for people that do not have too much experience in AutoX or on the track ,but if I had the stock rear bar I would've installed it right a way. BTW Tein RA's spring a is less aggressive than the 18kg / 10kg that you have.

On the tire size ,I had to increase my front from 235 to 255 righ after I went from -1 to -3 camber - the reason was that the braking power was noticeably reduced due to increased tire locks.

 

[prsrcokr]

It might be that crappy asphalt (I'm used to the same in VA )
You know the mk3 has variable toe, could that be adding to what you're talking about. At least it does if you've still got the pivot bushing in place on LCA #2. Then again, that wouldn't effect patch, just slip angle and scrubbing. I haven't tried the ST bar on stiff because it was so tail happy before, just figured I'd be better with a stiffer front bar to compensate, I've though of trying to find a stock rear bar again so I could run the same size front tires but I like your path of more camber and then running equal sizes. I've got plenty of brake power, yes even on stock calipers but need more front tire to improve braking. Threshold is tricky on race pads and narrow street tires, last weekend in 90+ deg. temps felt like a rain event at the end of some straights

Agreed, I think no bar would be ok on a lighter car but I feel like it helps the rear follow on the mk3 and allows you to get on the throttle earlier. Maybe I should compare with no bar to see but one thing mine does well is transition so I hate to loosen that up. Haven't messed with shock settings yet, still on the soft end mainly because I'm convinced most adjusters are cheap and won't be matched corner to corner. I'll try messing with them, maybe it'll feel a little more planted at a stiff setting?

 

[LordDigital]

The dynamic toe is a very interesting topic. First I believe that you are referring to the LCA#1 (Called No.1 Lower Suspension Arm in the Toyota documents as seen here). I’ve also noticed that the original arms had what appeared to be a pivot bushings. The first question is what that does , in my understanding of the way that the rear suspension works… when breaking this could only generated toe-out which is undesirable (HICAS and other active rear steering systems are known to generate some serious toe-in when breaking which could increase the high speed breaking stability). My LCA#1 is replaced by the A1 arms which does not appear to have the pivot bushing.

On the rear sway bar ,the only reason why I want to go back to stock is the weigh savings – with the extensions the ST bar might even be softer than the stock BTW fabricating twe two extensions was really easy - give them a shot for the next AutoX

The only thing that I’m missing from the stock brakes is the “cooling duct” ,from the cars I parted out I found 2 Toyota designs for these and the ones that I’ve used were taken from a 92 car ,huge intake openings – almost as big as the ones on the Mk4! BTW on street tires I don’t even have to use race pads with the BBK 1.25x13inch rotors

 

[prsrcokr]

I'm pretty sure the pivot is part of LCA #2, not the swaybar arm (LCA1) I remember this because I never replaced the pivot bushing because of it's purpose and trying to avoid a potential bind. Later, after snapping LCA1 (where the bushing had been replaced) I spoke with a few other mk3 guys that had the same happened multiple times. Since putting a stock bushing back in the arm (LCA1, swaybar arm) there have been no problems.

That was my understanding of the pivot, some Celica used this design as well. Since the pivot is at the rear mounting spot, wouldn't it only allow toe-in?

I believe you with a BBK, you got lots of heat sink and pad contact area. Are the pads lasting long too? I you ever go to some wide stickies you could add a race pad and have tons of braking. On the pads guru and I use, I've had 350Z drivers tell me they can lockup 275 710's fairly easily. You'd probably do a stoppie with them

 

[supraguru05]

lord did you buy those upper arms off of DR jonz. if so what is the part number off of them, also what is the part number on the ball joint. those are cheap hot rod circle track a arms and instead of rooting around a local shop for a hour measuring camaro a arms id rather just know the part numbers

 

[LordDigital]

lord did you buy those upper arms off of DR jonz. if so what is the part number off of them, also what is the part number on the ball joint. those are cheap hot rod circle track a arms and instead of rooting around a local shop for a hour measuring camaro a arms id rather just know the part numbers

Yes I got these from Dr Jonez together with the reamed spindles. I've asked him a few times to give me the original invoice so I could post the part numbers for the community ,unfortunately the only paperwork that I got was the original SPC instruction book which is pretty generic and titled" SPC performance (pro series) - instruction sheet for Adjustable Upper control arm for "custom Street arm" ".

In other words the SPC was the manufacturer ,he told me that he sourced them from here for around $350 and that he had to ream the spindle for the hotrod ball joints to work

 

[7Mboost]

Holy crap we can only get -1.0 up front? I haven't tried getting an alignment yet but I was planning on going -2.0F and -1.2R. Anyone have a DIY for custom UCA's? I might have to stick John Doward on this project.

 

[LordDigital]

I'm pretty sure the pivot is part of LCA #2, not the swaybar arm (LCA1) I remember this because I never replaced the pivot bushing because of it's purpose and trying to avoid a potential bind. Later, after snapping LCA1 (where the bushing had been replaced) I spoke with a few other mk3 guys that had the same happened multiple times. Since putting a stock bushing back in the arm (LCA1, swaybar arm) there have been no problems.

That was my understanding of the pivot, some Celica used this design as well. Since the pivot is at the rear mounting spot, wouldn't it only allow toe-in?

I believe you with a BBK, you got lots of heat sink and pad contact area. Are the pads lasting long too? I you ever go to some wide stickies you could add a race pad and have tons of braking. On the pads guru and I use, I've had 350Z drivers tell me they can lockup 275 710's fairly easily. You'd probably do a stoppie with them

You are correct the pivot bushing was on the LCA2 ,as A1 racing calls it "Camber Rod" but we all know that unfortunately it changes a lot of toe as well ... I remember when I was playing with the rear alignment on the track I had marks on two of the arms to vary just the toe in.... not a fun experience.

My pads live is great ,but I try not to use aggresive brake strategy as of yet - still learning the curves and I know that I can't be super fast One day if I go to 275 slick I would use the Blue 9012 - iirc the pads that Kirk uses...

 

[Doward]

Holy crap we can only get -1.0 up front? I haven't tried getting an alignment yet but I was planning on going -2.0F and -1.2R. Anyone have a DIY for custom UCA's? I might have to stick John Doward on this project.

In that case, how about adjustable tubular control arms up top?

 

[LordDigital]

In that case, how about adjustable tubular control arms up top?

As far as I know there a 3 options:

1. Be very lucky and find some old stock JIC UPC's camber only adjustable arms. They are great becouse you could truly have street and track settings.

2.Be a little less lucky and find the parts number to purchase some camber/caster adjustable arms from SPC.

3.Don't count on your luck :icon_wink and have someone replicate the JIC design for $$$. Not worth IMO because on MK3 due to the high r~1.8 it would be much more beneficial to have larger and adjustable LCA's ,as seen here

 

[prsrcokr]

I seem to remember someone (Dr J.?) telling me that the JIC arms had such a high starting minimum amount of camber (like -4 deg.) that they really couldn't be used for some applications and certainly not still streetable. Was there an earlier version that didn't have so much camber?

What is SPC? Dr. J and Howard H. were getting some custom arms done at one time that needed a different ball joint taper to use in the spindle to use. Not sure what happened with those, I kind of lost touch.

I have a feeling Jero spent quite a few bucks on those arms but they would be a nice improvement.

-Edit: read the other posts, you're where those UCA's ended up

 

[LordDigital]

I seem to remember someone (Dr J.?) telling me that the JIC arms had such a high starting minimum amount of camber (like -4 deg.) that they really couldn't be used for some applications and certainly not still streetable. Was there an earlier version that didn't have so much camber?

What is SPC? Dr. J and Howard H. were getting some custom arms done at one time that needed a different ball joint taper to use in the spindle to use. Not sure what happened with those, I kind of lost touch.

I have a feeling Jero spent quite a few bucks on those arms but they would be a nice improvement.

-Edit: read the other posts, you're where those UCA's ended up

I believe that the high starting camber for the JIC arms is either a myth or there was an earlier version with a lower starting camber. I saw a Supra in EU that had these arms and his street settings were not agresive at all. The good thing about the JIC arms is that the adjustability is at the ball joint point ,which gives a true ability to adjust the camber just before the track whether on mine arms every time I try to change the camber ,the caster changes as well and as a result of the "caster change" my toe settings would go off...

SPC is just the manufacturer of the parts that Dr.Jonez used to put his arms together. The bad news is that there are not any part numbers on the arms or the Ball Joint , the good news is that we are working with Guru to get the part number availible for the community.

BTW Dr.Jonez claims that he paid under $250 for BOTH arms ,ColoradoRacing sells very similar MK4 rear arms for around $400 ,so I guess that the current pricing should be somewhere in the $300 or lower... but we will see. And yes the downside of the lower price is that the HotRod Ball Joint is not plug and play and requires to ream your spindle ,I have no details on how much would that cost since I got the spindles from Dr.Jonez Car.