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Discussion Starter #1
Had a great time at the Shenandoah track which is right next door to Summit Point. The car performed better than expected but has some serious issues that need to be addressed. It makes ok power and now that it's going faster it won't stop and it won't turn. After one session when I pulled into the paddock my right front brake rotor and caliper assembly was on fire! The car won't turn and after it finally does with some serious trail braking, transition to power brings on some serious understeer at corner exit.

This is how the car is set up right now and I would like some guidance to all that it needs to be competitive in the SRX series which I will compete in at some level in the 2006 season. Not asking for any secrets here just a point in the right direction.

KYB AGX adjustables and H&R springs and a strut tower bar
Urethane bushings throughout the suspension
Stock bars
5zigen 17 x 7 Fighters with 215/40 Parada Spec 2's
Stock Calipers with Hawk Blues in front and Hawk HP Plus in the rear

What do I need?
What gains/benefits can I expect from the changes?
 

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Discussion Starter #3
Rockwood said:
the car would understeer the entire session, or after the caliper fire?

ditch the paradas.

Whole session. Caliper fire was probably caused by the fact that we were running counter clock wise (lot's of left hand corners including the two biggest changes in speed from 125 mph to 45 mph) and there are some pretty significant deceleration zones while the right side is loaded.

Any wheel and tire size suggestions would be great. I will probably use the RA-1's.
 

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Racingswh said:
Whole session. Caliper fire was probably caused by the fact that we were running counter clock wise (lot's of left hand corners including the two biggest changes in speed from 125 mph to 45 mph) and there are some pretty significant deceleration zones while the right side is loaded.

Any wheel and tire size suggestions would be great. I will probably use the RA-1's.
get a rear sway bar to help it rotate. what are your alignment settings?

i would run something more mild if you are new to road racing. the Yokomama ES100s are pretty good overall tires that last a while. mine have been through 2 track events in a moderately heavy (~2700lbs) FWD car for ~15,000 miles and they have about 50% left in them. i am not exactly kind to them on a daily basis either (VVL and open diff).
 

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Discussion Starter #5
Rockwood said:
get a rear sway bar to help it rotate. what are your alignment settings?

i would run something more mild if you are new to road racing. the Yokomama ES100s are pretty good overall tires that last a while. mine have been through 2 track events in a moderately heavy (~2700lbs) FWD car for ~15,000 miles and they have about 50% left in them. i am not exactly kind to them on a daily basis either (VVL and open diff).
Camber LF -.9 RF -1.4 LR -2.0 RR -1.8
Caster 6.1 6.4
Toe .09 .10 .41 .12

This was before the event. I have no adjustability other than what the stock suspension affords me.

Fortunately I have some exposure to road racing although this was the first time I had ever driven a front engine rear wheel drive car on a racetrack. I used Michelin Pilot Sport Cups on my old car and they worked well. I was thinking the TS-1's in the rain and RA-1's in the dry.

What do you think of the Whiteline adjustable bars?
 

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Racingswh said:
Had a great time at the Shenandoah track which is right next door to Summit Point. The car performed better than expected but has some serious issues that need to be addressed. It makes ok power and now that it's going faster it won't stop and it won't turn. After one session when I pulled into the paddock my right front brake rotor and caliper assembly was on fire! The car won't turn and after it finally does with some serious trail braking, transition to power brings on some serious understeer at corner exit.

This is how the car is set up right now and I would like some guidance to all that it needs to be competitive in the SRX series which I will compete in at some level in the 2006 season. Not asking for any secrets here just a point in the right direction.

KYB AGX adjustables and H&R springs and a strut tower bar
Urethane bushings throughout the suspension
Stock bars
5zigen 17 x 7 Fighters with 215/40 Parada Spec 2's
Stock Calipers with Hawk Blues in front and Hawk HP Plus in the rear

What do I need?
What gains/benefits can I expect from the changes?
You have a mildy modded street car as far as suspension and brakes, not a race car. It would only be competitve if you didnt have much compittion. You need R-Compound tires, a true racing strut shock spring combo, fully adjustable stuff for camber/caster, adjustable sway bars and bigger brakes at a minimum.

If you don't care about compittion just run it like it is until you do. At the least you don't have enough front camber/caster, too much rear, not enough brake, not enough spring rate and not enough wheel travel.
 

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Racingswh said:
This is how the car is set up right now and I would like some guidance to all that it needs to be competitive in the SRX series which I will compete in at some level in the 2006 season. Not asking for any secrets here just a point in the right direction.
http://www.sr20forum.com/showthread.php?t=113993

Thats a start. Look at the other threads he started as well. Get the Nasa Rulebook and read that. It's online on the nasa website.
 

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I hope to show good pics the whole time I am building my car as well as asking some beginner like questions(some I already have the answers to) to help all you other first timers out. Keep an eye on the thread that Steve just posted above.
 

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Discussion Starter #9
choaderboy2 said:
You have a mildy modded street car as far as suspension and brakes, not a race car. It would only be competitve if you didnt have much compittion. You need R-Compound tires, a true racing strut shock spring combo, fully adjustable stuff for camber/caster, adjustable sway bars and bigger brakes at a minimum.

If you don't care about compittion just run it like it is until you do. At the least you don't have enough front camber/caster, too much rear, not enough brake, not enough spring rate and not enough wheel travel.


I fully agree with your observation and I won't care about competition until next season. I am going to attend (as a spectator and information sponge) the sprint/enduro events at Pocono South in Pennsylvania near me in July and August. In addition I have signed up for six 3 day track events for this season to get seat time and experience driving this type of car.

Here are the questions I am having a hard time getting answers to. Other sites have information but the guys aren't racers like all of you who I see have the best and deepest wealth of racing knowledge. I am trying to avoid buying stuff 2 and 3 times and do it right the first time. (lol, This is the 2nd time really as this was the car my father drove at the August Watkins Glen event the last 2 years with the stock 90 rwhp KA in it and I added the suspension and wheels for him to give it a little more grip than a stock set up.)

Which are the best /most effective tires allowed in the SRX series in what width on what wheel?

For these cars which suspension manufacturer and model should be used for a racing application, not just a glorified street suspension? Same question for which components to make the suspension fully adjustable?

Brakes seem to be pretty straightforward as I will probably use a fastbrakes kit or 300ZX TT upgrade. I have had success with ferodo pads and will try some on this car. Any other thoughts welcomed on brakes.

Lastly, the comment that throws me is "not enough wheel travel". I am not sure what that means. I mean I think I know what it means but I am not sure why this would be desireable. In the past I have limited suspension travel as much as reasonably possible by increasing springs rates. In my experience weight transfer and the following body roll during transitions causes the tires contact patches to get larger and smaller. In the past I have had the most success with bigger tires with shorter sidewalls and limited suspension movement hence larger and more consistent contact patch sizes which has resulted in lower lap times. I can tell by your posts you know what you're talking about so I would like to better understand this concept of "more wheel travel."

Thanks,

Steve
 

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Racingswh said:
Which are the best /most effective tires allowed in the SRX series in what width on what wheel?
people have stuffed some huge tires under S13s. you could probably fit some sort of 255mm hoosier. not a forgiving tire though.

Racingswh said:
Lastly, the comment that throws me is "not enough wheel travel". I am not sure what that means. I mean I think I know what it means but I am not sure why this would be desireable. In the past I have limited suspension travel as much as reasonably possible by increasing springs rates. In my experience weight transfer and the following body roll during transitions causes the tires contact patches to get larger and smaller. In the past I have had the most success with bigger tires with shorter sidewalls and limited suspension movement hence larger and more consistent contact patch sizes which has resulted in lower lap times. I can tell by your posts you know what you're talking about so I would like to better understand this concept of "more wheel travel."
technically, weight transfer is the same regardless of suspension. its the body movements and related geometry issues that warrant a stiffer suspension setup. you generally want to limit the movement of a shitty suspension (like B13s) with higher rates, and allow better suspensions to work.

you probably have a small amount of shock travel left with your stock style suspension setup. in order to "gain" more travel, you must give up some rebound travel. shortened struts or adjustable length struts are the easiest way to do this. if the fronts bottom out on your car first (likely) then the car will go into terminal understeer because of the near infinite spring rate of a bottomed strut. a bottomed out front suspension will cause eternal plow syndrome because its spring rate is infinite.

you can gain travel by cutting your bumpstops, getting Koni bumpstops (which will be less abrubt, but won't gain you any travel) or by shortening your struts/shocks. you could also gain travel by moving the spindle, but that is something beyond the scope of what most are willing to do (save mike).
 

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Discussion Starter #11 (Edited)
Rockwood said:
people have stuffed some huge tires under S13s. you could probably fit some sort of 255mm hoosier. not a forgiving tire though.


technically, weight transfer is the same regardless of suspension. its the body movements and related geometry issues that warrant a stiffer suspension setup. you generally want to limit the movement of a shitty suspension (like B13s) with higher rates, and allow better suspensions to work.

you probably have a small amount of shock travel left with your stock style suspension setup. in order to "gain" more travel, you must give up some rebound travel. shortened struts or adjustable length struts are the easiest way to do this. if the fronts bottom out on your car first (likely) then the car will go into terminal understeer because of the near infinite spring rate of a bottomed strut. a bottomed out front suspension will cause eternal plow syndrome because its spring rate is infinite.

you can gain travel by cutting your bumpstops, getting Koni bumpstops (which will be less abrubt, but won't gain you any travel) or by shortening your struts/shocks. you could also gain travel by moving the spindle, but that is something beyond the scope of what most are willing to do (save mike).
Does the Hoosier fit into the last "Any tire UTQG rating" clause? Also, I will run a tire from a company that supports NASA, the SE-R series and our interests as long as it's reasonably competitive.

I was happy to see you caught that about weight transfer. That's why I stated "with the following body roll" which is a result of the weight transfer.

Got ya I think. "Gaining" more travel is actually allowing the suspension to work instead of bottoming against the bumpstops. Believe me when I tell you that the way it's set up now the front is crushed against them. I was thinking incorrectly when I was envisioning the car gyrating around with "more wheel travel." When the suspension is in this bottomed state midcorner bumps can be quite exciting (lol!) as there is no more travel at all to absorb them.
 

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Racingswh said:
Does the Hoosier fit into the last "Any tire UTQG rating" clause? Also, I will run a tire from a company that supports NASA, the SE-R series and our interests as long as it's reasonably competitive.
oh, whoops. for a second, i though that SRX had unlimited tire choices. i would just run 235-40-17 toyo RA-1s or the 245 size. they arent the "best" per se, but they will give you good lap times, be consistent, don't cost much and last forever (comparatively).

Racingswh said:
I was happy to see you caught that about weight transfer. That's why I stated "with the following body roll" which is a result of the weight transfer.
yeah, i is smat. :D

Racingswh said:
Believe me when I tell you that the way it's set up now the front is crushed against them. I was thinking incorrectly when I was envisioning the car gyrating around with "more wheel travel."
that's not good. fix it. :D
 

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Discussion Starter #14
Rockwood said:
oh, whoops. for a second, i though that SRX had unlimited tire choices. i would just run 235-40-17 toyo RA-1s or the 245 size. they arent the "best" per se, but they will give you good lap times, be consistent, don't cost much and last forever (comparatively).:D
It states wheel width as 10" max. A 275/40 would have great support on a wheel that width. I will run a 255/40 in front on a 9" rim. I think these are actually the same sizes that Maximum Motorsports recommends for the AI Mustangs.


Rockwood said:
yeah, i is smat. :D
I think I agree with that lol


Rockwood said:
that's not good. fix it. :D
Which coil overs are best and which front top camber plates and adjustable upper rear camber arms should be used? Just a manufacturer name that builds stuff that will withstand race applications. At this time my choice for coil overs is the Tein RE coil over set up which comes with a 560 lbs inch front spring and 450 lbs. inch rear with what looks like stiffer race springs available.
 

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Racingswh said:
It states wheel width as 10" max. A 275/40 would have great support on a wheel that width. I will run a 255/40 in front on a 9" rim. I think these are actually the same sizes that Maximum Motorsports recommends for the AI Mustangs.




I think I agree with that lol




Which coil overs are best and which front top camber plates and adjustable upper rear camber arms should be used? Just a manufacturer name that builds stuff that will withstand race applications. At this time my choice for coil overs is the Tein RE coil over set up which comes with a 560 lbs inch front spring and 450 lbs. inch rear with what looks like stiffer race springs available.
I would run a 300ZX rear spindle, which loses about 8 lbs of unsprung weight perr side, converts to 5 lug where there are a lot more choices in wheels and allows you to run big rear brakes. For ease of getting, I would run Tein RS shocks (be sure to get the S14 stle rear lower mounts to work with the Z rear spindel) and springs with the pillow ball mounts and front camber plates, the tubular fully adjustable suspension arms and tie rod ends from SPL, Progress sway bars, S14 front 5 lug conversion, Stop tech brakes 13" 4 piston in front, 13" 2 piston in the rear. Make a triangulated front tower brace and run a Nismo power brace in the front.

Run the Nismo 3 way adjustable R200 LSD. Run 17x10 with a 35mm offset in the rear and a 17x9 with a 30 mm or so offest in the front with a 275/40-17 rear, 265/40-17 in the front with any number of the fiberglass wide body front fenders and wide body rear overlays avalible for this car. You will have to pound the seam in the front wheelwell flat and do a little cutting, welding and triming in the front wheelwell.

Run 6 degress positive front caster, 2.5-3 degrees front negative camber, zero front toe and use the control arms and tie rod spacers to correct the roll center and bump steer. For the rear, run 1.5 degrees negative camber, 1/8" toe in and correct the roll center.

If you are feeling tricky, relocate the front mount of the rear lower control arm down about 1.5" to make it paralle to the ground to get rid of rear lift to make on throttle handling better, tie the subframe together by adding reinfocing tubes between the two upper arm mounts (Upper control arm and traction rod). Relocate the front mount of the tension rod so its paralel to the ground to remove front anti dive.

You S13 guys have it so easy, you can just buy your crap right off the shelf!

When combined with a proper cage which in an SRX car will be almost a semi tube frame, and about 400 whp which is a piece of cake in a RWD DET, this will whip the **** out of nearly anything.

With a few exceptions this is the same setup as what we ran on the turbo magazine D-1 drift cover car.

There you have it, no engineering almost all off the shelf, bolt in easy full f---ing race car. When it comes to a SE-R where we have to have nearly everything made by semi custom expensive exccentric poor service suppliers this is great, like having a Honda.
 

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choaderboy2 said:
You S13 guys have it so easy, you can just buy your crap right off the shelf!

When combined with a proper cage which in an SRX car will be almost a semi tube frame, and about 400 whp which is a piece of cake in a RWD DET, this will whip the **** out of nearly anything.

With a few exceptions this is the same setup as what we ran on the turbo magazine D-1 drift cover car.

There you have it, no engineering almost all off the shelf, bolt in easy full f---ing race car. When it comes to a SE-R where we have to have nearly everything made by semi custom expensive exccentric poor service suppliers this is great, like having a Honda.
Oh no, Mike is say good things about the S cars. Better watch out. This is FWD territory around here ;)
 

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Discussion Starter #18
choaderboy2 said:
I would run a 300ZX rear spindle, which loses about 8 lbs of unsprung weight perr side, converts to 5 lug where there are a lot more choices in wheels and allows you to run big rear brakes. For ease of getting, I would run Tein RS shocks (be sure to get the S14 stle rear lower mounts to work with the Z rear spindel) and springs with the pillow ball mounts and front camber plates, the tubular fully adjustable suspension arms and tie rod ends from SPL, Progress sway bars, S14 front 5 lug conversion, Stop tech brakes 13" 4 piston in front, 13" 2 piston in the rear. Make a triangulated front tower brace and run a Nismo power brace in the front.

Run the Nismo 3 way adjustable R200 LSD. Run 17x10 with a 35mm offset in the rear and a 17x9 with a 30 mm or so offest in the front with a 275/40-17 rear, 265/40-17 in the front with any number of the fiberglass wide body front fenders and wide body rear overlays avalible for this car. You will have to pound the seam in the front wheelwell flat and do a little cutting, welding and triming in the front wheelwell.

Run 6 degress positive front caster, 2.5-3 degrees front negative camber, zero front toe and use the control arms and tie rod spacers to correct the roll center and bump steer. For the rear, run 1.5 degrees negative camber, 1/8" toe in and correct the roll center.

If you are feeling tricky, relocate the front mount of the rear lower control arm down about 1.5" to make it paralle to the ground to get rid of rear lift to make on throttle handling better, tie the subframe together by adding reinfocing tubes between the two upper arm mounts (Upper control arm and traction rod). Relocate the front mount of the tension rod so its paralel to the ground to remove front anti dive.

You S13 guys have it so easy, you can just buy your crap right off the shelf!

When combined with a proper cage which in an SRX car will be almost a semi tube frame, and about 400 whp which is a piece of cake in a RWD DET, this will whip the **** out of nearly anything.

With a few exceptions this is the same setup as what we ran on the turbo magazine D-1 drift cover car.

There you have it, no engineering almost all off the shelf, bolt in easy full f---ing race car. When it comes to a SE-R where we have to have nearly everything made by semi custom expensive exccentric poor service suppliers this is great, like having a Honda.
Thank you! I didn't expect that kind of help and I appreciate it more than you know. This answers all of the "mystery" questions I was finding it so hard to get answers to. If you're ever in the East and you need anything PM me. Dyno tuning, car storage, transport or accommodations don't hesitate to ask, no BS, let me know.

Thanks again,

Steve
 

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98sr20ve said:
Dave really likes the Quaife for a track car. Nismo is a lot less money. I assume this nismo is not to hard hitting from what you are recommending.
I don't like the quaife fro more than mild power gains, gear diffs make the car unstable with high speed wheelspin.
 

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Racingswh said:
Thank you! I didn't expect that kind of help and I appreciate it more than you know. This answers all of the "mystery" questions I was finding it so hard to get answers to. If you're ever in the East and you need anything PM me. Dyno tuning, car storage, transport or accommodations don't hesitate to ask, no BS, let me know.

Thanks again,

Steve
For details on adjusting roll center, anti-drive, anti-squat and bump steer, read my on going articles in SCC. They have good diagrams making this stuff easier to understand.
 
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