Hillclimb suspension: softer or firmer setup?

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hufflepuff
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Hillclimb suspension: softer or firmer setup?

Post by hufflepuff »

Greetings, from a prospective hillclimber!

My car is a 2005 Mazda RX-8 that is notionally SCCA DSP (underprepped from a performance standapoint, but that's fine). I have received feedback and clarification on the safety requirements, but i wanted to ask a few general car setup questions to determine whether i'd want to make any significant car changes before the first event.

My RX-8 is prepped for autocross and road courses and is honestly on the softer side as far as most go. My spring rates at the wheels (accounting for motions ratios and such) are about 300 lbs/in on each corner, and suspension frequencies are around 2.1Hz F&R.

I'd looking for some feedback on typical production car setup at hillclimbs, specifically:

- Are the hills relatively smooth, or bumpy?
- Do most guys transitioning from autocross and HPDE/ road course setup to hillclimbs need to soften the car or raise the ride height to avoid scraping or bottoming?

Thanks in advance for the feedback.
Matt Huffman
2005 Mazda RX8 - DSP
http://www.youtube.com/mchuffman
Rich Rock
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Re: Hillclimb suspension: softer or firmer setup?

Post by Rich Rock »

The hills aren't racetrack smooth, but overall they're relatively smooth.

My suggestion is, over the next couple months, go to the hills you're thinking of running and check them out yourself. That will give you a sense of the surface and type of courses you'll be dealing with. It might help guide your decisions. Nothing better than seeing for yourself!

If you can't do that, my suggestion is to just run some events with your current setup before spending money on changes.

Having said all that, I'll just say that most people end up with a fairly stiff suspension:-)

Rich Rock
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Mark Aubele
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Re: Hillclimb suspension: softer or firmer setup?

Post by Mark Aubele »

hufflepuff wrote:Greetings, from a prospective hillclimber!

My car is a 2005 Mazda RX-8 that is notionally SCCA DSP (underprepped from a performance standapoint, but that's fine). I have received feedback and clarification on the safety requirements, but i wanted to ask a few general car setup questions to determine whether i'd want to make any significant car changes before the first event.

My RX-8 is prepped for autocross and road courses and is honestly on the softer side as far as most go. My spring rates at the wheels (accounting for motions ratios and such) are about 300 lbs/in on each corner, and suspension frequencies are around 2.1Hz F&R.

I'd looking for some feedback on typical production car setup at hillclimbs, specifically:

- Are the hills relatively smooth, or bumpy?
- Do most guys transitioning from autocross and HPDE/ road course setup to hillclimbs need to soften the car or raise the ride height to avoid scraping or bottoming?

Thanks in advance for the feedback.
First of all, welcome. DSP is a very active class and I hope to see you out! You may be the first RX8 we've had!

In regards to suspension setup, I will be one of the few I am sure to tell you to leave the car stiff, or more importantly how you have it setup for autocross/road course. The setup won't be much different, if at all, although you might want to take some rear bar out to tighten it up a bit. But honestly what is fast on a road course is going to be very close.

Some of the hills are pretty bumpy, but I have run cars that most would tell you would be WAY too stiff for hillclimbs. My '14 GT had huge swaybars and 800/350 springs (700+ wheel rate up front 350ish rear), I was running 550/700 on my E36 this year, and in the past I ran 800/900 on the same chassis (had a better damper on that car that would handle the rate). I will be going to somewhere around 900/1000 this year on the same car (800/450 ish wheel rate plus front swaybar, no rear bar).

Honestly driving the hill is much more important than setup at first. Again, look forward to seeing you this year. Don't hesitate to ask more questions.
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hufflepuff
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Re: Hillclimb suspension: softer or firmer setup?

Post by hufflepuff »

Awesome, I'll just bring my setup as-is and focus on fun and learning. Looking forward to it!
Matt Huffman
2005 Mazda RX8 - DSP
http://www.youtube.com/mchuffman
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Josh R.
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Re: Hillclimb suspension: softer or firmer setup?

Post by Josh R. »

Hey Matt! I headed over here after you commented on my videos to see if you were posting haha! Yeah it’s more important to just get out to the events and get started learning the courses and how PHA events run.

I found the in my case suspension set-up for autoxers and road racers was VASTLY different with the road racers running CRAZY high spring rates. So I did what any non-scientist would do and split the difference. Then last year bumped up the rates a bit more getting a little closer to the road race “recipe.” So in short, as Mark said, I think the right answer is more toward stiffer setup.
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