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Understeering like the Enterprise

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Best Answer JeffBaker , 09-09-2017 07:56 AM

Final thought: 6 deg of caster seems like a whole shit ton.  Are you running offset bushings in the front?  Doesn't the NA caster max out around 3-4 deg? That's all we were able to get out of it.   Incorrect caster will cause terrible bump steer.  Something that I am still battling with 2 years later on my NA.


Thanks for the feedback. Fwiw I've never had a problem getting caster. This car does have offset spherical bushings, with the Mazda corrective tie rod ends. The car will attain 7.2 degrees on both sides. I've always run 6, but now that you bring it up I will look at it and do some testing.

At the track last week, I did loosen the front swaybar and that definitely helped - but i loosened it from a setting that was previously working very well. So my feeling was that I was using lateral roll rate to compensate for some other porblem - root cause was still out there. Go to the full post »


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#21
Brandon

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"New setup, and the guy who did the setup is very fast as well"

 

I wonder if this is a part of your issue.  Certainly something I've heard many times from racers who get the "fast guy setup".  I know when Kessler sets up my car, he doesn't give me the same setup as his pro driver whose used his Miata's. 

 

Are you now back to the set-up you were super excited about at Thompson?

 

Ditto on Kessler and his setup for us NA (SM) drivers - I believe he has a base set for each platform and tunes/adjusts from there based on your performance.

I'd also bet his NA ITA setup is slightly different considering the variability of shocks, spring rates, and bushings.

 

Sounds like you (Jeff) went to SAC and had that shop (SAC) setup your car. Perhaps the message didn't get to the guys turning the wrenches to give you "Elivan's setup"?

 

From what I recall seeing of his '99 and his driving style, he likes to "drive on the bumpstops", has tons of negative camber (upper eccentrics), and likes things loose so perhaps translating that over to your NA ITA car something was lost?

 

I hope you can get back to your regular setup shop as I know how you feel when things aren't "right" and you're fighting an ill-handling car all weekend.


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#22
JeffBaker

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I think the solution has been to remove the rake, set at the height we felt was a good start for the tires and spring rate, and put back the alignment that seemed to work.

PB and a near track record at WGI on Monday. Totally blew it on Tuesday, though...but the car was fantastic.

Thanks everyone for the shared education in alignment.
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Jeff Baker

Wilton, NH

 

ITA Miata 42

NER SCCA

COMSCC


#23
luvin_the_rings

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So looks like I need to get back to the alignment rack and check my car for more caster? 

 

Why am I stickied at the top of this thread? 



#24
Johnny D

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Why am I stickied at the top of this thread? 

 

Jeff gave the "Best Answer" and he was replying to your quote.

 

J~


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#25
Jesse Prather

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Hey Jeff.  Something that is always overlooked is also shock settings.  Where are your shocks set?  Those shocks can and will transform the way a car handles.  All adjustments are clicks from full stiff.  Rebound on top, compression on bottom.  Count the clicks heading stiffer and keep good notes on where they're set.  Happy to help with some shock tuning.  Don't be afraid of those knobs.







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