1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Caster how much is too much?

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Old Jun 21, 2015 | 07:39 PM
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Caster how much is too much?

After modifying my crossmember to get the camber I need, I knew that I would probably need to adjust the strut rods since I was moving the control arms a half inch out on each side.

https://www.rx7club.com/1st-generati...amber-1083131/

I adjusted them in a way that seemed to be ok but now I really have a lot of caster, I measured it at almost 11.5 degrees. Another big clue is that the wheel is almost an inch and a half closer to the front of the wheel well than it is to the back. Almost everybody says when setting up a race car you just set caster to max, but I think they are talking about just sliding the camber plates all the way back, which I have done, with the strut rods left in the stock setting.

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The best information I have been able to find is that stock caster is about 4.5 degrees and race setups are around 6 degrees. At this point I think I will adjust the strut rods back until I have 6 degrees and see how that works.
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Old Jun 21, 2015 | 10:08 PM
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leave it, how's it drive?
i did an alignment on a newer mercades a few months back and its' caster was like 12.. or 15.. something i thought was WAY high... but it was the factory settings..
lots of sports cars run in the 8s and 9s..

also that intake manifold is killing you! ever compared the s4 throttle body to that gsl-se one? it's a major bottle neck.
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Old Jun 21, 2015 | 10:18 PM
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My E Production racer friends run 6 degrees. That is where my STU car is set at right now but I have not driven it on a track yet.
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Old Jun 22, 2015 | 07:56 AM
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Originally Posted by lastphaseofthis
leave it, how's it drive?
i did an alignment on a newer mercades a few months back and its' caster was like 12.. or 15.. something i thought was WAY high... but it was the factory settings..
lots of sports cars run in the 8s and 9s..

also that intake manifold is killing you! ever compared the s4 throttle body to that gsl-se one? it's a major bottle neck.


I have a complete S4 13B sitting in my basement just waiting for some quality time with my die grinders…

On the GSL-SE throttle body I did remove the secondary throttle plates, the fast idle mechanism, and all of the other emissions and street stuff.
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Old Jun 22, 2015 | 09:03 AM
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we only run 6 degrees of caster because thats about all we can get. 11 is high, but it should drive like a mercedes.
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Old Jun 22, 2015 | 09:10 AM
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when you do the swap, get an s4 ecu coils/ CAS. i first used the gsl efi stuff, and you gain alot of lower end torque with the s4 ecu doing your ignition timing, rather then using the old dizzy. my s5 motor felt damn near like the stock SE motor until i swapped the ecu /coils. then i finally had enough fuel to go over 5.5k rpm... what i didnt expect was the lower rpm gain.
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Old Jun 23, 2015 | 10:10 AM
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Yes I have everything to swap over, the ECU, the coils, the AFM. I also have a front cover and oil pan from another GSL-SE engine to install on the new engine. At this point the only thing I need is a wiring harness, the guy I bought the engine from cut the harness at the firewall and it would probably just be easier to get another harness instead of trying to patch up the one I have, I went through the pain of paring down the GSL-SE harness that I have to the bare minimum to get the engine to run well so it shouldn’t be as hard the second time around.
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