Chassis integrity for autocross |
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Chassis integrity for autocross |
Stltri |
Feb 8 2021, 01:04 PM
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#1
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Member Group: Members Posts: 70 Joined: 13-April 15 From: SoCal Member No.: 18,622 Region Association: None |
Curious as to how to determine if the chassis is stable or fit for autocross for a car without the stiffening add ons.
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john77 |
Feb 8 2021, 04:32 PM
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#2
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Senior Member Group: Members Posts: 621 Joined: 21-February 14 From: Los Angeles Member No.: 17,027 Region Association: Southern California |
I AX'd my car for two years on 16x7s with semi slick 205/55 Toyo Proxes R1Rs.
The car had no chassis stiffening or reinforcement and I had zero issues. I mean, apart from me being a sh*t driver. The car was "rust free" though. |
horizontally-opposed |
Feb 9 2021, 12:18 AM
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#3
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Advanced Member Group: Members Posts: 3,432 Joined: 12-May 04 From: San Francisco Member No.: 2,058 Region Association: None |
I AX'd my car for two years on 16x7s with semi slick 205/55 Toyo Proxes R1Rs. The car had no chassis stiffening or reinforcement and I had zero issues. I've been surprised by how well 914s have held up to autocrossing for all of the discussion about weak chassis, etc. I think part of that was driven by the weaknesses discovered in circuit racing and major loading at very high speeds over long distances. After 255,000+ miles, with many hard miles on all sorts of sticky tires that fit into standard fenders, I have yet to see a chassis crack other than The Crack commonly seen on the driver's side inner longitudinal—which was very small and easily welded up. And someone told me they all do that… Go ultra wide on tires, or simply wide slicks, and YMMV… |
DRPHIL914 |
Feb 9 2021, 07:43 AM
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#4
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Dr. Phil Group: Members Posts: 5,768 Joined: 9-December 09 From: Bluffton, SC Member No.: 11,106 Region Association: South East States |
I AX'd my car for two years on 16x7s with semi slick 205/55 Toyo Proxes R1Rs. The car had no chassis stiffening or reinforcement and I had zero issues. I've been surprised by how well 914s have held up to autocrossing for all of the discussion about weak chassis, etc. I think part of that was driven by the weaknesses discovered in circuit racing and major loading at very high speeds over long distances. After 255,000+ miles, with many hard miles on all sorts of sticky tires that fit into standard fenders, I have yet to see a chassis crack other than The Crack commonly seen on the driver's side inner longitudinal—which was very small and easily welded up. And someone told me they all do that… Go ultra wide on tires, or simply wide slicks, and YMMV… i am curious, ive only run 2 autocross sessions in my 914, and i have 16" fuchs, 6" up front and 7"rear, 205/55 but indy 500 firehawk tires which are a 300 wear rating so i could go own to 200 and add some grip to the rear which got loose a bit 2x last time, but front stuck tight and handled great so would i gain anything or loose to put 7" up front? stock 2.0 motor with factory sway bars front and rear, sport bilistein rear shocks and 100# springs, really very little body roll,- so i have a feeling that wider not always better, i may add 2 degrees negative camber in rear by lowering a notch and add just a bit of toe out up front for next time out, add some 200 rated toyo or such and just get it balanced out. anyone else have any thoughts on the additional widty, 6" vs 7" up front? btw in rear with the 205 on 7" rim gives me 8.5" of tread contact on the ground! and btw last time by my end of session i had closed the gap and tied the other 914 driver in our class that was running on 8" and9" flared car with suby motor, double my HP output --- oh quick edit, to answer the question of the OP i had my rust issues addressed with all new floowrs rear longs and jack points that repair and some additional metal really tightened up the chassis i did not opt to do any of the more extensive longs stiffening. but, if i were going bigger track and full time ax car then i guess it would benefit for for 5-6 fun days a year i think thats way overkill - but maybe if you are in there already then do that if you can do it yourself, , but i will not do that to this car. |
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