Suspension advice needed pics and video within - LotusTalk - The Lotus Cars Community
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post #1 of 9 (permalink) Old 10-18-2015, 01:26 PM Thread Starter
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Suspension advice needed pics and video within

So I had the second AX in the exige yesterday and it looks like my suspension is far too soft and or my roll bar needed to be firmer. Check out this picture from the middle of a 35 MPH left hander:



Then here is a video from another run not sure if you can gleam much about the suspension from this.

My observations from the video is that I am just not turning hard enough (there is never any slip angle on the tires and I am often going wide) or getting on the gas hard enough or soon enough or staying on it through the slalom like I should be. I was about 2 seconds slower then I "should" have been based on the other lotus there.


I am on the following setup:
Track pack shocks set 5 front 8 rear
BWR hardcore sway bar all the way soft (I lowered it because it felt like I was pushing too much last time, but maybe I was just driving too hard the first time out).
RE71R tires at 23.5/25 psi cold in 225 and 245 on LSS wheels
Monoballs and upgraded sway bar bushings.
Front ride height 115mm (too low I know, but I got it aligned before I changed tires and didn't take into account the lower profile tires. Rear 130
Alignment 1/4" out front -2.1 camber 1/8" in rear 1.9 camber
Not corner balanced, I had a passenger in the picture, but not the video.
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post #2 of 9 (permalink) Old 10-18-2015, 05:09 PM Thread Starter
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Ill try again now that the evening crowd is done dinner
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post #3 of 9 (permalink) Old 10-19-2015, 07:57 AM
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You need to start with higher spring rates to control the body roll.
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post #4 of 9 (permalink) Old 10-19-2015, 08:11 AM
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I believe that the track pack springs are progressive which is definitely not ideal for consistent feel, and as you can tell they like to roll a lot.

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post #5 of 9 (permalink) Old 10-19-2015, 09:05 AM
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Spring rates need to go up if you want less roll. I'd recommend the Ohlins springs that come with their matched shocks. I have a set that I may be convinced to depart with. They are 370 front and 470 rear, roughly. PM if you want to talk about it.

If you intend to stay on street tires, I would not recommend going much stiffer than the Ohlins rates. I've tried it and the car gets kind of skatey.
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post #6 of 9 (permalink) Old 10-19-2015, 01:06 PM
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I'm no an engineer, but tuning the car based on how it leans in a photo is probably not the best way...
As far as I understand it from most of the Caroll Smith books is that suspension should be compliant enough to not skate over the imperfections and stiff enough to not bottom out. Then you go for transient characteristics and fine tune the feel... with a stopwatch.
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post #7 of 9 (permalink) Old 10-20-2015, 08:53 AM
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Mine does the same thing. My shock dampening isnt set as high as yours. Id be interested in swapping springs.
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post #8 of 9 (permalink) Old 10-20-2015, 09:49 AM
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Sadly your roll is due to the track pack suspension. I was educated in their downfall from others in my autox crew. They have a "soft" spring at the top/bottom of it that is only like 1.5" long. That spring is super soft and helps with the compliance of minor bumps. So what you are feeling, is the first 1.5" of your suspension being compressed before you ACTUALLY get into your real spring rates. I was informed, that honestly you would do MUCH better on LSS shocks than track packs. No matter what you do, you can not get away from this issue with the track packs...a side from removing that little helper spring and putting in a solid piece of rubber/metal.

So my suggestion...if you are fairly serious about Auto X...sell the track packs and get Penske D/As from BWR. Totally worth it.

My 2cents.

I should also say...Kfennel after relooking at the first photo...NICE JOB ATTACKING that corner. AWESOME!!!

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post #9 of 9 (permalink) Old 10-20-2015, 10:56 AM
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What Giantmcm said. The track pack shocks are terrible and the springs are worse. I had a customer with track pack exige buy our NA Penske shock setup with stiffer springs JUST BECAUSE IT RIDES SO MUCH BETTER! Lotus has to drive to a low cost, we all understand that, but whoever signed off on the trackpack setup should be kicked in the jewels a few times.....


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