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Organized Drag Racing and AutocrossDrag racing and autocross discussions and questions. Techniques, tips, suggestions, and "what will I run?" questions.
I haven't posted much recently. My little blue 3rd gen has been busy taking on the hated Fords and some really nice 3rd and 4th gens in SCCA Road Racing. I had a horrible week with transmission issues and rear-end changes but was able to cut a decent lap on the last qualification session at Road America and put the car P4. The race turned out really nice.
Watch the great coverage on the link below. This car is getting old. Been racing for 15 years. BTW I am the Blue Number 54. These cars are built to the very limit of the rules. I ran a 2:27:5 in qualifying. If anyone has run their car at Road America you will get an idea of how fast that is with a 309 CI motor with a Holly 600CFM carb with 10.2 compression and a solid lifter .500 lift cam on really bad heads. No comment on the hood thing long story
Nice job!!!!.....Id like to know the rundown on your car. My Iroc is more like a GT/highway car it is not a drag car. It does the odd track day It has a Pro Kit the stock size tires and Tokico "blue" struts and shocks (got them super cheap, SFC's and a bunch of bolt on rear susp stuff. Im looking for a nice stable high speed car, Might do the odd track day at Mosport (fast track like RA)
My car is extensively modified and built to the SCCA American Sedan rules so everything has been done with compliance and speed in mind. The car currently has a custom 3-way Adjustable RideTech Strut and JRi 3 way rear shocks. Adjustable Panhard bar and decoupled third link. Brakes are Bremo Monoblock 4 piston front and 4 piston rear. Custom aluminum front hubs with a spacer between the bearings so the nut is torqued to about 150 ft/lbs. Custom Speedway sway bar-I have 5 different center sections. No rear bar- they make these cars go slower. Springs currently are 900 front and 300 Rear. I have run from 700 to 2400 front springs. Full Floater 7.5 rear end with Moser Hubs with and an Auburn carrier. Hewland MVE 4 speed dog box. Tilton peddle assembly. All solid bushings or heim joints in the suspension everywhere and I mean everywhere.
Let me know what else you want to know about the car. This car has been developed over the last 15 years.
Last edited by 3rdGenA/SRacer; 10-22-2020 at 08:48 AM.
With 15 yrs of development you are a racers best new friend. Raced that track way back in the early '80s in a Toyota Celica getting my butt beat by the new CRXs.
Developing a new third gen for low buck endurance racing. Think junk yard engineering, craigslist parts, with as much self fabricating skills as possible . With not much time, schedule, or money for multiple track tune days. Would like to show up to race with a close baseline setup. Our car as of now; '91 RS convertible, 305TBI, T5, 3.72 torsen posi 4th gen rear end, LS rear brakes, C6 front, stayed with iron hubs in front. Chassis; welded all the seams , panels, and spot welds I could find, All suspension is either heim joints or delrin bushings, Adj. panhard bar, adj. PB mounts fabricated( lowered 1 1/2"), 3/4" taller ball joints, fabricated LCAs in front, stock spring location, used bump steer kit, 950# springs in front, 250# in rear, Used Koni dbl adj. all around, 1 1/4" solid bar in front, 1" solid in rear. Whole car lowered only 1". Staying with 275 40 17s 200 TW for now
Would love to know some of your deeper car balance opinions. Our goal is consistency , easy to drive ( not twitchy ), not kill the tires. 10 to 24hr race days
Did you play much with your front and rear roll centers ?
How did you balance roll couple between the front and rear ? frankly your delete of the rear bar scares the P!@p out of me But I'm open
Did you use any chassis setup software ? looking in to this now
Any advise or lessons learned in the long term ?
As any racers knows its chassis prep that wins races ( or at least lets you have fun in the car ) Not guesses and reading multiple opinions on the interwebs
Good questions. First point you have to remember that these are not very stiff purpose built race cars so you have to take that into consideration. Spring rates seem close I would take the rear bar off and put 75 to 100 more rear spring in the car. I used a Suspension Analyzer from Performance trends. Built a complete 3D model. Given all the time I really didn't learn much. Made some same adjustments so the the front anti dive was consistent side to side and cleaned up a few other minor things. The front roll center is will be lower than the rear but there is not much I am able to do given the rules. I use the panard bar adjustments to adjust the balance and it works great. Believe it or not it is really hard to mess the handling up on these cars. They just aren't that sensitive. Remember when I race this car it is driven very very hard. i.e. tire slip angles are pretty high to get the most out of these cars.
Key lessons;
More spring is better than bigger bars.
Adjust the panard bar to adjust how much rear grip you get.
Get the corner weights right.
Run a **** ton of camber 4.5 degrees. There is very little camber gain. If the rules allow it get as much camber and toe as you can in the solid axle. We are only allowed .5 camber so I don't have any but it does help.
Run a ton of caster. Caster makes everything better on the race track.
Shocks do not affect how these cars handle. They just cost a ton of money. You want a shock with minimal rebound and compression. Quadraliner in a digressive manner is best with a knee around 1.0 in/sec. Keep maximum damping in the 250 lbs. range.
Lastly most importantly-learn to drive the living heck out of the car.
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My car is extensively modified and built to the SCCA American Sedan rules so everything has been done with compliance and speed in mind. The car currently has a custom 3-way Adjustable RideTech Strut and JRi 3 way rear shocks. Adjustable Panhard bar and decoupled third link. Brakes are Bremo Monoblock 4 piston front and 4 piston rear. Custom aluminum front hubs with a spacer between the bearings so the nut is torqued to about 150 ft/lbs. Custom Speedway sway bar-I have 5 different center sections. No rear bar- they make these cars go slower. Springs currently are 900 front and 300 Rear. I have run from 700 to 2400 front springs. Full Floater 7.5 rear end with Moser Hubs with and an Auburn carrier. Hewland MVE 4 speed dog box. Tilton peddle assembly. All solid bushings or heim joints in the suspension everywhere and I mean everywhere.
Let me know what else you want to know about the car. This car has been developed over the last 15 years.
Wow thats modded thanks for the info! I have an old magazine article that gives the rundown on a Camaro that was used in Silver State events...no rear bar. I have a real race car too. Rebodied 1999 Nascar makes 700+ that I roadrace but Im not much of a third Gen guy. Theyre a strut car totally different from what Im used to in set up compared to the truck arms and all that in the racecar but I know the feel Im looking for. The thing is nervous at speed. Works pretty well on an autocross though lol Youre saying throw some caster at it?. Some camber caster plates would be a start I guess It is a street car with air and all that makes good power 450hp 406 but i want it to handle well and be stable and reassuring at speed.
that is awesome! Road course racing takes a ton of effort and I applaud you for that. I had my car on a road course track a few times and it is a blast, but a whole different element than I am used to. Very cool !
The modifications are endless on this car. Everything has been optimized that can be under the rules. I do run longer Ball Joints. I have a love hate relationship with the Dog Box. It is almost impossible to imagine how crazy the transmission is. On the track, it works nicely and is very strong. In the pits not so good but that is the entire car. It only likes going fast
The modifications are endless on this car. Everything has been optimized that can be under the rules. I do run longer Ball Joints. I have a love hate relationship with the Dog Box. It is almost impossible to imagine how crazy the transmission is. On the track, it works nicely and is very strong. In the pits not so good but that is the entire car. It only likes going fast
I get it your car is super specialized. Im a bit of an information junkie and Im digging around for road/ roadrace set up info anywhere I can from someone with some real results to back up their claims. it's not that common for these cars. There is an overload of drag race set up info however. Keep diggin' Thanks!
10-20-2020, 01:49 PM
