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Discussion Starter · #1 ·
I need to shave an average of 1.5-2 seconds off my typical times to be competitive locally in DSP and PAX and I'm beginning to think the TRD Sportivo suspension is becoming a weak link in my car's preparation. I'm looking for more grip, sharper steering response, less body roll and less gyration over uneven surfaces. The car feels a little soft at autocrosses and track days, especially the front end. I rarely bottom out the suspension, but I'm wondering if stiffer dampers and springs would be worth any time on course.

I can't help noticing how the front running cars in my region all have visibly stiff adjustable shocks. My car will continue to be a daily driver, but even on 15" race tires, the ride is good enough for me now, so I can tolerate a stiffer set-up.

I've been thinking of rebuilding the Sportivo suspension with Koni shocks and strut inserts, but wonder how well they'll work with the Sportivo springs. Should I go all out and have my current suspension converted to coil-overs with new springs or will the inserts be enough? If I go with any sort of custom set-up, I'll probably have the work done at Tri Point Engineering - who backs a team of Mazda Proteges in the USTCC and is a Koni authorized shock builder/rebuilder).

Thanks for any advise.

(And yes, I know the best mod one can make is to the driver.)
 

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The sportivo kit is nice for a daily driver, but it is a far cry from a competitoin setup (as you are seeing now).

The best f the best don't even run sway abrs because their springs are so stiff.

Look at the spring rates on the Tein HA then multiply by 1.5, that will get you into the ballpark that you need to be in.

Unfortunatly, this means shocks and springs. I'd be looking at 500+ lbs up fornt and probably clsoe to 1000 lbs in the rear. It won't make a nice daily driver.

Even then, 1.5-2 seconds is tough to make up, if you are anything like me, you are jsut being outdriven. The local hotshoe in a Type R will beat me by 1-2 seconds, and my car isn't too bad in DS, it's a combination of the R being better, and the driver being MUCH better.

Also, what about Hoosiers? While the back to back tests don't have them being much faster, my experience is, it's easier to drive them faster than it is the Kumhos, that goes for concrete and asphault (but not gritty surfaces where a little tread helps).

Still, even just doubling your spring rates will help, and it won't be all that stiff (just about 320 lbs in front and 500 in the rear).

Scott
 

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Hi Erik!

It has been a while since we instaled your Sportivo. I'm faced with the same problem. I've been with this set-up for 3yrs. With the exception of experimenting with rear sway sizes, I drove with the Sportivo suspension virtually unchanged. It's funny, looking back, how I couldn't find any fault and now I clearly notice the Sportivo's limitation. Personally, I want less body-roll. I'm willing to try stiffer springs but my main concern is getting the damping right.

I still plan to go custom valving with Konis using the Sportivo damper rates for the softest setting. And, now that I have a hunch TRD purposely overdampened the shocks in relation to springrate, I really want to see the dyno numbers. It will be intresting to see how the Sportivo damper and spring rates match up before going any further.

Here's the thing. Tri-Point charges $15 per shock dynoed. That's $30 for the front and rear. However, removing the shock will require re-alignment during instalation (and, I really don't want to fuzz with my alignment right now-- I'm heading up to Willow on the 21 and 22 this month). Thats another $45. I don't mind using my shocks for the test but if you are due for alignment we can just use yours. So, there you have it $75 dollars and $37.50 if we split the cost.

Let me know what you think so we can plan some more.
 

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Discussion Starter · #4 ·
Ray - I'm up for visiting them when my chaotic work schedule permits. Have you discussed prices for different set-ups? It sounds like changing spring rates is the best way to go. I'm curious what the total package would cost. When are you available to meet up?
 

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Here are the price quotes given to me by Tri-Point.

Koni sport rebound adjustable
8641-1409 front $135 each
8041-1276 rear $95 each
A complimentary dyno graph of purchased dampers including compression and softest and stiffest setting of rebound if purchased from them.

Coil-over kit
I forgot to ask what make. Most likely Ground Control. Any specified spring rate you want. $65 each

If you wish, they will remove the oem spring perches $65 each.

Custom re-valve or rebuild of Koni shocks $95 each including dyno graphed results.

They can duplicate any damping rate of any shock from initial bump all the way to the end stroke on Koni re-bound adjustables

I've estimated $1,100 for a custom coil-over kit with custom damper valving to any spec you want.

It's quite a lot of money but very tempting.
 

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Discussion Starter · #6 ·
autxr said:
...if you are anything like me, you are jsut being outdriven.
Scott
Yep. June Evo School here I come. I hope work doesn't screw it up.

Actually $1100 for a well tuned custom suspension doesn't sound too bad.
 
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