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Discussion Starter #1 (Edited)
I have been reading and preparing another AW11 for autocross. Our local club event lot is very small (high school lot) and well suited for an AW11. I am passionate about Supra’s and AW11’s…and I am taking a liking to this little autocross car. I have an 87 MK1b that is just too nice to beat on as a daily driver and wanted something else to be used for autocross as well. So I purchased a local 1986 MK1a from an Ebay seller and started preparing.

Images from the Ad...






This is a completely stock AW11, except for 14 inch OZ wheels and floor mats, but maybe even the tape deck.

I am not new to AutoX, just trying to work on my skills. There are several knowledgeable autox people here and hope that they will chime in and reduce my learning curve. The following is a list of my settings, parts, and a few images. There is also a video being uploaded as well.

I first replaced the air intake with an Amsoil dry filter and prefilter to keep water out. I did this only because the OEM air box was developing much rust and did not like the idea of rust particles being sucked into the intake. I then started working on the smaller issues, like door locks, small crack in the windshield, and replacing the OEM door cards with Techno Toy Tuning (T3) replacement door cards.

Then it was time to get serious and make some real changes:
Suspension:
- Custom T3 strut tubes (Powder coated red) with 2.5 inch Eibach coilover sleeves
- MK2 Koni Race dampers all four corners, set full soft I believe
- Front springs 600#/in
- Rear springs 400 #/in
- Sway bar removed
- T3 camber plates, all four corners
- Polyurethane bushings

Wheels/Tires:
- Enkei RPF1 15x7 +35
- Bridgestone Potenza RE-71R in 205-50-15
- New lug nuts, valve stems, and centering rings

Alignment:
- Front
o Caster: +4.7
o Camber: - 2.2 (could not get more, tire would interfere with coilover springs…will need to find a solution for this…wheel spacer?)
o Toe: 0.20 degrees IN
- Rear
o Camber: - 2.2 (matched the front)
o Toe: 0.20 degrees OUT

Ride Height:
- Set the rear to 24 inches from the shop floor to the center of wheel arch; after race the springs have settled approximately a ¼ of an inch
- Fronts were set higher at approximately 24.5 inches; did not measure settled height when I got home from first AutoX

Interior:
- Seats are OEM and you can see my helmet sticking out the top of the sunroof. Martin (gtfour77) has offered some assistance in the future.
- A Momo hub + NRG quick release hub was added to push the steering wheel away. A Momo 350mm steering wheel with the wheel NRG adapter was borrowed from one of my Supras, to save cost of another wheel

There are many more plans but this is what was needed in order to move from ES to STS. I am in hopes that more can be done to the engine, as it needs more to dual with the Miata and others.

More images and videos soon!
 

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Discussion Starter #2 (Edited)
Video Evidence...

Had a great time today and welcome feedback / constructive criticism. The car needs some work as well as my skillset. I hope you enjoy the video of half of my runs today. They are taken at different vantage points to better understand what the car is doing. Thanks for the input.

YouTube Video Located HERE...
 

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Discussion Starter #3 (Edited)
Images from the AutoX event...

The upgraded suspension completely changed the car for the better. I got compliments, was having a great time learning and making better passes, and even learning the limits. You can toss the car into a turn and it wants to go. I need to work on potential horsepower, fix that exhaust, work on keeping momentum by better right foot control, when to trail-brake if at all, and how to best use the brakes in a mid-engine car. The AW11 really needs more grunt as I was in position 3 of 6 in my class. Two Miata's were always ahead but the suspension changes really did help me focus on my driving. And as anticipated, when asked about the setup, most were very happy with how flat the car stayed and most said to put a sway bar back on....which I told them that I was committed to giving this setup a try. It honestly rode very comfortably. Jamie drove the car to and from the meet, as I was in charge of towing the club trailer, and she thought it was relatively comfortable as well. She took several hundred images of my AW11 and other event participants. Here are only a few...

The stance...I need to learn how to set my roll centers correctly. Here is an image showing the rear lower than front (on purpose) and then some images of the suspension movement...













I anticipate getting advice to increase the front and rear spring rates by 50-100 #/in per corner. The tires did not squeal much, but I do not know how to interpret the rear wanting to come around on me. Increase the front rate to keep the rear planted? With the compression noted at the rear as well, all four corners need more spring? When do you know that you have gone too far with spring rates? I did not dial any strut into the runs...I am pretty sure that they were all full soft setting as I did not change them from when they came to me. Perhaps dial in 2-3 clicks before making a spring change or do both? I am trying to learn the rationale here.

Thanks all and I do appreciate the advice and input.
 

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You could mess with spring rates but... there are other things I would start with.

First, you are missing you apex's by too much, especially on the right turns. I use freeway bots dots to figure out markers on the hood (and I always need to experiment with this or I end up missing apexes by a mile). Second, you are smidge behind on the slaloms. Turn a bit earlier.

With regards to setup, you don't have enough camber. I would go to at least -2.5 front and rear, although 3+ is probably appropriate. I would also go with a smidge of toe in for the rear. Next would be tire pressures? The video of the front looks like you are hair low, but you would need to try it. Lastly, do some runs with full stiff on the struts.

There is definitely room for setup improvements. The transitions are as quick as they should be cable of. Here's and good example of what should be achievable. http://www.rhoadescamaro.com/build/?cat=23 Compared to a mk1, the his car has narrow wheels and is seriously under tired.

It's hard to tell when you are too stiff with the springs. Basically the car starts to skitter. Its hard because the force that can come from the spring or the struts. If the struts are too soft, then you can use stiffer springs. So, ultimately deciding if you have too stiff a spring forces you to consider if your struts are matched to your springs. that said, there is a good chance you are lighter than you need to be in the rear and possibly to heavy in the front. Your call.

Frankly there are too many changes above to be reasonably tried in 1 event. It's something that you should spread out a bit. Good luck,

O
 

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Discussion Starter #5
Owen,

The advice is much appreciated, from driving style to setup. Good idea to learn the edges of the car with the dots. I will look into this.

I agree, there are too many things to change. I will be in touch with T3 as the coilover and wheel offset prevent any additional camber...might need to go from an 8 inch spring to a 6 or 7 inch in front and make sure that my camber plates are set correctly. I do need more, though...agreed.

And when I inflated the tires to 38 psi, I thought for sure that was way too much. I only inflated them that high to help ensure that the tire flex would not hit the strut tubes...looks like I do need more pressure as well. ... might try 40-45 psi. The wear on the tires was at the edge showing rollover.

I should have made an adjustment with the struts while on course. I will look into the MK2 koni race struts and check the max/min settings and go from there.

Thanks again for the advice.
Chadrick
 

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In terms of modifying, focus on the camber before anything. Good chance the camber will fix the tire pressure issues. Did you install the struts yourself? If so, did you remember to preload the camber (finger tight on the strut bolts, then jack the suspension up a bit before tightening)?

Since this is primarily a toy, consider using spacers to get the clearance.

Lastly, most high level ST strut cars use camber plates that are adjusted all the way in for suspension geometry, then adjust the camber by fiddling with slop at the strut bolts.

O
 

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Discussion Starter #7 (Edited)
In terms of modifying, focus on the camber before anything. Good chance the camber will fix the tire pressure issues. Did you install the struts yourself? If so, did you remember to preload the camber (finger tight on the strut bolts, then jack the suspension up a bit before tightening)?

Since this is primarily a toy, consider using spacers to get the clearance.

Lastly, most high level ST strut cars use camber plates that are adjusted all the way in for suspension geometry, then adjust the camber by fiddling with slop at the strut bolts.

O
Owen,

Thanks again for the feedback. Here is how the 8 inch springs sit now...


This is also why I was unable to get more camber on the entire setup. So I pulled the rear to match the front.


I also messed up and oriented the camber plates incorrectly, causing one side to not give the max amount of camber...I set the gold beveled edge of the camber plate outward instead of inward limiting my camber and I have to move the camber set screws as a result. This was my bad but will be fixed when I drop the suspension again for a spring change.


This is not the correct way, boys and girls. I usually have much better attention to detail but dropped the ball in my haste to get to the alignment. Once at the alignment, I had to move the bolts closer together.

I was really hoping that XHead and some of the other guys from the older STS sticky thread would venture in here as well and provide some advice on spring rates, since I have to drop the suspension anyway.

I was comtemplating 50 to 100 lb/inch increase at all four corners...but would really appreciate someone looking at these images and video and advising. I have already moved the struts to 1/4 turn off the max firmness. I also am likely to move from an 8 inch spring to a 6 inch spring in front, in hopes that the coilover collar will sit high enough to clear the tire and give me plenty of camber adjustment, without the use of a wheel spacer, and clearance for any tire flex and movement during a race. That current gap seems very tight to me.

I also thought that spacers were illegal in STS? If not, would a slim 5 mm give me more space at the hub for more camber? You mentioned adjust max camber at plates and then dial in at the hub. I was actually hoping to max at the hub, and then dial -1.5 or so for the days I drive it to work and around town, then have another mark on the plate that gives me -3 degrees in front and -2.5 in rear...to kick it over at the event (I usually drive to events as well). Issue with this train of thought? Will toe likely be affected to a great degree (no pun intended) and not allow this type of dual adjustment?

I would like to point out that T3 has had stellar communication and even with a couple issues, they have been an excellent company to deal with and conducted business with the best interest of the customer. Much appreciated Gabriel.

Thanks again ... it is a work in progress.
Chadrick
 

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You have sway bars?

Not that familiar w your STS prep level but looking at how your car lurches and rocks like a boat you need some major sway bar increase. Look at your pictures Chad your wheels on the high side are barely touching the racing surface. Your turning on 2 tires.

Granted you can diddle with spring rates but that does nothing to transfer the weight from your low side to the high side.

You want your car to be flat in a turn. This will allow the tires on all FOUR corners to work. Camber the crap out of the car but you will not improve the tire patch relative to weight transfer.

Coil overs aren't the answer folks. You have to think bigger and tune the whole suspension.

Have you discovered tire "treadware" tuning yet? With a 60/40 weight distribution this is a "MUST".

Mister 2 Tim
A Toyota Race Team since 1986



 

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Meh, you aint even in the ballpark for camber. Fix that first. Spin the tops and see where that gets you. New camber, playing with extreme ranges of damping is enough fiddling for one event. Everything else is future work.

Regarding clearance, yes it looks pretty darn close to me too. Are their any marks on the springs from the tires? If not, I guess you got enough. To get more, I just read the ST rules and spacers are not specifically allowed, however, I've know plenty of people who have run them and if you are worried about it, glue them to the wheels and roll it into the "any wheel" rule. Lugs and nuts are allowed using the street class rules. That said, if push comes to shove you can always slot the lower bolts for camber. It's not preferred, but it does work and I've never heard of anyone with an MR2 having problems with it.

From the pics, I would use the other strut holes and readjust the springs. This will help make ensure you have proper travel and springs stay where they should. It looks pretty short on travel as is.

Generally speaking camber isn't that bad on tire wear, although it does get notable when you are running well over 3 degrees. Toe is the real killer. It doesn't take much to send your wear through the roof. You do not want to adjust your camber before driving home, unless you also want to adjust your toe.

O
 

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Discussion Starter #10 (Edited)
Not that familiar w your STS prep level but looking at how your car lurches and rocks like a boat you need some major sway bar increase. Look at your pictures Chad your wheels on the high side are barely touching the racing surface. Your turning on 2 tires.

Granted you can diddle with spring rates but that does nothing to transfer the weight from your low side to the high side.

You want your car to be flat in a turn. This will allow the tires on all FOUR corners to work. Camber the crap out of the car but you will not improve the tire patch relative to weight transfer.

Coil overs aren't the answer folks. You have to think bigger and tune the whole suspension.

Have you discovered tire "treadware" tuning yet? With a 60/40 weight distribution this is a "MUST".

Mister 2 Tim
A Toyota Race Team since 1986
Thank you for the feedback. Not trying to make a big deal but I go by Chadrick, not Chad. And I admit that I am trying a new suspension setup here. I have done the big sway bar thing with a Supra and am still trying to get better handling through tuning. So I came across a sticky in this sub forum and am giving it an honest try before going back to sways. But I will look into the term "treadware tuning". What was your suspension setup, if you don't mind sharing?

Meh, you aint even in the ballpark for camber. Fix that first. Spin the tops and see where that gets you. New camber, playing with extreme ranges of damping is enough fiddling for one event. Everything else is future work.

Regarding clearance, yes it looks pretty darn close to me too. Are their any marks on the springs from the tires? If not, I guess you got enough. To get more, I just read the ST rules and spacers are not specifically allowed, however, I've know plenty of people who have run them and if you are worried about it, glue them to the wheels and roll it into the "any wheel" rule. Lugs and nuts are allowed using the street class rules. That said, if push comes to shove you can always slot the lower bolts for camber. It's not preferred, but it does work and I've never heard of anyone with an MR2 having problems with it.

From the pics, I would use the other strut holes and readjust the springs. This will help make ensure you have proper travel and springs stay where they should. It looks pretty short on travel as is.

Generally speaking camber isn't that bad on tire wear, although it does get notable when you are running well over 3 degrees. Toe is the real killer. It doesn't take much to send your wear through the roof. You do not want to adjust your camber before driving home, unless you also want to adjust your toe.

O
Well there are no marks on the springs or inner tires.

So my plan for the next event:
- 650#/in. 6-inch front springs
- 450 #/in. 7-inch rear springs
- correct orientation of camber plates
- I ordered caster camber gauge, toe plates, and ride height measurement tools from Lonacre and will build platforms to set my car on from my lift so I can get under it easier...alignments will get expensive.
- hopefully my new exhaust is here for installation
- run with koni race dampers at 3/4 firm
- increase tire psi to 40 psi, mark the sidewall with chalk
- zip tie a front and rear strut to check travel
- attempt to install seats from Martin and get my head inside the cabin
- order a set of 5 mm wheel spacers for the front wheels, just in case
- centric slotted rotors, centric sport pads, braided lines, and Amsoil DOT3 flush...noticed one side wanted to lock up at exit of course but not the other....need to renew and flush

I know that is a lot, but hopefully as it gets dialed in, there will be fewer adjustments at a time.

I welcome continued input.
Chadrick
 

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But I will look into the term "treadware tuning".
hmm.. tough subject for a message board, and a dual use car on street tires. Basically it's looking tires after running and seeing how they are wearing to determine what the next adjustment to make should be. For auto-x, I rate it slightly more effective than using a pyrometer, but a lot harder to do.

I know that is a lot, but hopefully as it gets dialed in, there will be fewer adjustments at a time.
Not that much. A lot of these things aren't terribly inter-related. I'll also go on the record guessing that the zip ties will end up at the bump stops.

O
 

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And when I inflated the tires to 38 psi, I thought for sure that was way too much. I only inflated them that high to help ensure that the tire flex would not hit the strut tubes...looks like I do need more pressure as well. ... might try 40-45 psi. The wear on the tires was at the edge showing rollover.
I've heard reports of the RE71-R liking pressures of mid to high 20's. You are losing a lot by running that high of pressures. As others have said, I would aim for much more camber. At least 3, if not closer to 4 degrees. As Owen said, camber doesn't really cause that much extra tire wear, it's mostly toe. It might cause uneven tire wear, but you can always flip the tire on the rim anyways. You definitely don't want to play with camber at an event, any change in camber changes your toe. Any wheel offset is allowed in the class, so I don't see why a spacer wouldn't be legal. I think you would want to space out the front anyways for more front track width.

Where are your ride heights relative to stock? It doesn't look that low, but overlowering can cause increased roll angle.

Any ideas on the weight of the car? I run 850F/500R spring in my 2500# Mk2, and some (XHead..) say it's too soft. Those rates might work for your lighter car though. I don't know that a 50# rate increase will do much for you.

How is the balance of the car? Is it steady state under or oversteer? Does it transition under or oversteer? I can't really tell from your video. If you can get away with rear toe out and still be stable, that is a good setup. It looks like you may not be pushing the car hard enough though.
 

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Discussion Starter #13
Guess I should weigh my car...

I've heard reports of the RE71-R liking pressures of mid to high 20's. You are losing a lot by running that high of pressures. As others have said, I would aim for much more camber. At least 3, if not closer to 4 degrees. As Owen said, camber doesn't really cause that much extra tire wear, it's mostly toe. It might cause uneven tire wear, but you can always flip the tire on the rim anyways. You definitely don't want to play with camber at an event, any change in camber changes your toe. Any wheel offset is allowed in the class, so I don't see why a spacer wouldn't be legal. I think you would want to space out the front anyways for more front track width.
I thought there was no way you were correct, then I started searching. I will try to drop my tire pressures to 31-32 for the first run, chalked...and will get -3.5 front and -3 rear and see what is up with those runs. My Longacre equipement has not showed up yet and will need a crash course in setting alignment here at home. Will likely go as aggressive as possible, to and from event...then reset camber and toe afterwards to prolong tires.


Where are your ride heights relative to stock? It doesn't look that low, but overlowering can cause increased roll angle.
I believe the ride is settling a bit. When walking out to the car from work, I thought it was a touch lower today. ...maybe just me. I was actually trying to search for optimum ride heights to use without RCAs.

Any ideas on the weight of the car? I run 850F/500R spring in my 2500# Mk2, and some (XHead..) say it's too soft. Those rates might work for your lighter car though. I don't know that a 50# rate increase will do much for you.
I knew I should have gone up by 100 instead of 50!! @#$!$% Shame to spend that money and not use them. I bet they are already in route. One things for sure, now I want to make a trip by the truck scales just to see the weight of this car. I thought I was getting spring rates that would only need tweaked...but sadly realized it was only an educated guess.

How is the balance of the car? Is it steady state under or oversteer? Does it transition under or oversteer? I can't really tell from your video. If you can get away with rear toe out and still be stable, that is a good setup. It looks like you may not be pushing the car hard enough though.
Toward the end of the run, the last right hand sweeper, and even an earlier right hand sweeper, the rear end would get loose if I enter too hot...so it did seem like I wasn't pushing the car hard enough (was actually trailbraking a couple to see if that helped stability...and it resulted in the fastest run of the day) but initial turn-in feels much more stable but would have to get out of throttle to help with transitions and found mostly loose on exit. I attributed to a very soft setting on struts, and needing more spring and more pressure in order to assist with body roll. Now I found, through a search, that the 71r's can get loose on a longer sweeper at higher pressures (although I do not know the setup of the reporting racer).

Camber, spring rate increase, 3/4 strut firm, and lower tire pressures + a few other tweaks will hopefully make a vast improvement

I appreciate all the input and thought provoking discussion.
Chadrick
 

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Discussion Starter #14
Any ideas on the weight of the car? I run 850F/500R spring in my 2500# Mk2, and some (XHead..) say it's too soft. Those rates might work for your lighter car though. I don't know that a 50# rate increase will do much for you.
I was very curious to know the weight. So my local truck scales came in handy. The little AW11 was not noticed to be on the scales until I had to jump up and hit the scalemaster button....they didn't even see me on there. And I was not able to get a weight of each axle, as the entire car fit on one pad.

Anyway, I am a bit shocked at the results. Full trim, full tank of fuel, with me in the car weighed 2,640 pounds! Wow, if 850/500 is too soft for your 2500 lbs, then I am way off! Almost disappointed to swap out only a 50 pound increase on all four corners. I didnt know my car needed to go on a diet. Now I have to see what can be done, but likely not much in an STS class.
 

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Discussion Starter #15
AutoX on 9-20-15

Planning the next phase of this build was not so smooth. After weighing the car I was anticipating needing much larger spring rates. I installed the 600# spring from the front to the rear of the car. I then installed only the 650's in the front. I know the ratio is way off but I thought that rate in the rear was much more appropriate instead of 450. I wanted to install 900 #/in in the front but they did not arrive in time....so I went with the 650's.

I put my longacre products to work and after setting ride height, I dialed in these alignment settings:

Alignment:
- Front
o Caster: +4.7
o Camber: - 4.1 using 6 inch springs
o Total Toe: 1/4 inch IN

- Rear
o Camber: - 3.7
o Total Toe: 1/4 inch OUT

Our regional SCCA club is small so we use modified classes, rear wheel drive street tires, rear wheel drive race tires, front....etc. In the rear wheel drive street tire class, I got 4th out of 14. The guys that were ahead of me were 1) Corvette Z06 (C7), 2) BMW M3, and 3) 2015 stock Miata. The Miata was ahead by 0.615 seconds.

My times:
67.128+1 (I decided to not use brakes for some reason.)
51.190
50.454
49.591 (Pressures building, reduced to 35 psi front and rear)
48.868 (31 psi front and rear)
49.337 (30 psi front and rear)
49.040 (did not adjust pressure as I was hoping I would get some pressure back)

I think that I need stiffer springs in the rear again. I will likely need to install the 900s with the 600 rear springs and see if it changes the balance.

Also, on the last two runs, the last especially, I felt the clutch slipping. It is time to look for a clutch that I can launch and not worry too much about it. More to come here...

I have images and videos being posted soon.
Chadrick
 

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Discussion Starter #17 (Edited)
Images from the event...

You can tell I dialed in much more camber for the event...


I still need to get my head in the car! Ha!

Here is a long sweeper setting up for the second pass:


another shot...


There is still too much lean. But this was expected due to front spring rates being a bit too soft.

I did make a larger jump in the rear spring rates and am a bit surprised to see the amount of movement in the back...




I slid the rear around the first turn a couple times, enough to know that traction was an issue, and even drove in aggressive enough to get the inside tire to pick up enough to lose some momentum through one of the corners.

- Wow, how much more of a jump in the rear rates do I do now?!?
- Would the front soft rates affect the rear this much or is it a separate issue?
- The car turns very well, compared to before, but feels loose coming out of the turn and you can see my attempt at trail-braking through the slalom to keep the rear end happy
- When I started reducing tire pressures between runs, my times improved. I got to 31 front and rear for my fastest run of the day. 30psi were my last two, but there were clutch issues. Perhaps I could reduce the rear pressures by a 1-2 psi and run 31 psi in front to attempt to get the car to understeer a bit more?

Thanks for the input and hope that this is at least entertaining for some.
Chadrick
 

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Sounds like a solid improvement. What about all the other stuff? How's the clearance and the suspension travel? Did you get a chance to play with the strut settings or did you just check them and leave them set at 3/4's?

- Wow, how much more of a jump in the rear rates do I do now?!?
I wouldn't do anything for now. From what I have seen, you can't even be sure the springs are working like springs. Before you start spending more money and time changing out springs, you should make sure they are.

- Would the front soft rates affect the rear this much or is it a separate issue?
Related. And a good chance it's more complex than it sounds. Also probably not worth it. You think you have too much roll, but how much do you have? You can take those pictures and figure it out that you have a ~ little over 2 degrees. The angles are such that you can't really tell how much is due to tire deflection, but a ballpark from other tires is that it's probably about 25% of the total roll. The part you can control with springs and bars is difference. And for that part, if you DOUBLE both front and rear rates the roll for that difference will be cut in half -and you have about 30% less roll in the pictures.

30% less than a little isn't much of a change. And double a high rate is way too high. Translation, your days of being able to make large change to body roll and alignments by changing a spring are over.

- When I started reducing tire pressures between runs, my times improved. I got to 31 front and rear for my fastest run of the day. 30psi were my last two, but there were clutch issues. Perhaps I could reduce the rear pressures by a 1-2 psi and run 31 psi in front to attempt to get the car to understeer a bit more?
Maybe. Any pressure that is not the optimum will reduce traction compared to the optimum - up or down. Since you do not know your optimum pressure, you could actually end up with more oversteer at the limit. In fact, if you got more understeer at the limit, it would be a sign that your tire pressures are too high.

I concur that it appears to have oversteer on corner exit, but would also add that it appears to have mid-corner oversteer and entry understeer.

For the next step, fix your clutch!

If you wanted to do more would add a stock front bar on (I know, I don't like them on optimized setups, but they are cheap and useful for experimentation up to that point), bump the rear struts to max and take a half a degree of camber out using the clevis bolts (I'm willing to bet you have too much camber). At the event, I would continue experimenting with tire pressures and if you are happy with that move on to fiddling with the struts.

O
 

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Discussion Starter #19
Thank you for replying, Owen. I was beginning to think all this time spent on this forum was a complete waste of time. The MR2 forums I frequent just don't get the amount of traffic I would desire. Perhaps Facebook is killing this type of documentation.


Did you get a chance to play with the strut settings or did you just check them and leave them set at 3/4's?
I left them at 3/4. I will dial them up to just off max for the next event. When changing the front springs again, I will pull a strut and make sure I got what I paid for...the MK2 Koni Race dampers. These feel very soft.


Owen said:
I wouldn't do anything for now. From what I have seen, you can't even be sure the springs are working like springs. Before you start spending more money and time changing out springs, you should make sure they are.
Owen said:
And double a high rate is way too high. Translation, your days of being able to make large change to body roll and alignments by changing a spring are over.
Hmmm...the new front set is already shipped. I will likely stop going up on the front rates and was told that I may need to go up a touch more in the rear and ditch the 150% ratio idea...to not make the difference in rates quite as much. Time will tell after the fronts have been changed.


Owen said:
In fact, if you got more understeer at the limit, it would be a sign that your tire pressures are too high.
Owen said:
I concur that it appears to have oversteer on corner exit, but would also add that it appears to have mid-corner oversteer and entry understeer.
So this rationale would be that my pressures are too low given the oversteer? Perhaps I should change the rear toe from 1/8 OUT to 1/16 OUT or even 1/16 IN before making a tire pressure adjustment?


Owen said:
For the next step, fix your clutch!
Amen. Parts ordered. Now to decide whether to drop the engine/trans together or only the transmission in ease of repairs...hmmmm...thoughts?


Owen said:
If you wanted to do more would add a stock front bar on (I know, I don't like them on optimized setups, but they are cheap and useful for experimentation up to that point)
If I want to take rates higher, I will add the front bar back at this point and check response instead of going up on front rates anymore. Good advice for a cheap response check.


Owen said:
Take a half a degree of camber out
When I told Martin what I was running, he too said that it was too much. It is nice to know I can dial that much in with this setup. I will dial back to -3.5 front and -3 rear for the next event. And then I will try 31 psi front and 29-30 psi in rear in an attempt to turn better. But the above information makes me think that this will not improve oversteer in center to end of curve. More study is needed / advice accepted.

Thanks again for your time and effort in helping with my setup.
Chadrick
 

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Face book is killing message boards, but don't feel too bad – this stuff was never really on the boards. Optimizing a setup takes a surprising amount of time and is to a large extent personal preference. Since no one runs your exact setup... you were pretty much always guaranteed this fun.

Can't help you with the clutch. The only time I've seen mine was when the engine was out for other reasons. You'd be better off asking on the general mk1 board. Good news though, changing clutches isn't really setup dependent so you will almost certainly get some solid answers!

As for tweaking the handling for auto-x, you should understand that you are still in the shake down phase. Shake down is characterized by just making sure things work as intended and you typically make gross and or multiple changes between events. This is important, because you are starting to ask tuning questions, and those will never be answered unless you are changing one thing at time (well, maaybe two).

To affect a change to the oversteer/understeer balance there are two things you can do:
1. gain traction on one end of the car.
2. lose traction on one end of the car.
Conclusion, anything that can change traction can change balance. Major things that can change traction are: struts, bars, springs, camber, tire pressure, toe, tire make, tire size, tire temperature, weight, wheel width and a slew of other things.

Realistically, changing the front springs, rear tire pressure, front camber, rear camber and thinking about changing toe makes it VERY hard to say what the total effect will be. Here's my guess as to what will happen. The camber changes will result in approx equal changes (increase) in grip both front and rear. You wont be able to feel the difference based on the rear tire pressure and the stiffer front springs will result in significant increase in understeer which will be nice mid turn and corner exit, but will add the hesitation you already have on turn in.

Of course, if it doesn't work out that way you wont know which part of the above is wrong. Which is why tuning (and experimenting) exists.

Go ahead and put in the front springs and change the camber. Play with tire pressures (ONE axle at a time) at the next event and see what happens.

As for your struts, try and get the full KONI part number. If you have it, you can get a rough idea what your valving looks like now. Even if you have what you think you do struts, a performance re-valve is not that unusual.

O
 
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