preparing first gen for csp, looking for opinions/advice
 

i did some searching, and this is the combo that i have come up with so far for my 85 rx-7. just looking for any additional advice or opinions on this set up

-13x7 steel wheels with 215/15/13 kuhmos
-350 lb ground control front coilovers, 175lb ground control rear springs
-tokico adjustable struts
-front strut bar
-sway bars: i'm thinking of getting the racing beat matched set, but have also read that you can just get an updraded front and ditch the rear. looking for advice in this column
-panhard bar/third member: another area where i am not sure what to do. i'm looking for the best legal handling setup i can get, not sure what to do about the rear end. i've read the watts linkage binds up, and i'l like to get rid of that
-poly bushings: sway bar and front control arm
-carbotech bobcat brake pads and steel braided lines
-4.10 gear out of gsl-se
-lsd: another one i am not sure of. i've heard some prefer the open diff over lsd on these cars. i've looked at torsen and phantom grip, but have read the phantom is a joke.
-lightweight seats
-rb full streetport exhaust: i know i don't have street port, but its a nice setup
-sterling modified stock carb on modified rb holley intake manifold: i like the simplicity of this manifold
-misc other things: direct fire ignition, pulleys, electric fan, light steel flywheel, clutch, battery behind pass seat, better oil cooler

think this is it so far, i'm sure there is more i will think of. any opinions/suggestions?

get the G-Force Engineering Tri-Link upper 3rd link,
the G-Force panhard bar
and the G-Force front strut/balljoint spacers

get a lighter flywheel and clutch assembly

get a race carb and intake manifold

You need all of these items to take full advantage of the CSP rules; if you don't do it then someone else will take advantage of you.

Talk to Carl @ PB & J Racing about a carb. He did wonders for my IT carb www.pbandjracing.com

pb&j, thats the sterling carb i was talking about. plan on the carb, manifold, flywheel, clutch, didn't think csp can use the spacers, and i was looking at the panhard/tri link, just wanted some reviews. thanks

-Find aluminum wheels if possible. Wider is better.
-Try ISC for your springs. Your #'s are about where I started with. My fronts are at 400# now.
-For the front - get 85-86 rear MR2 Illuminas.
-I have a Koni bar on front and removed the rear bar.
-My car was pretty good without going the panhard rod and tri-link setup. But to go faster you'll need it. This was my next step until I bought a completed CSP car.

-I use some Hawk pads (forget which variant) and have been impressed.
-With either 215/50-13 or 235/45-13 you may be shifting into 3rd more than you'd like with the 4.10 gears.
-lsd is good. From what I understand the Torsen from a Miata is better - my new car has a Torsen in it.
-lightweight seats are a good idea. Update and backdate to get your car even lighter.
-I have the RB full streetport exhaust :-)
-I have a twin 36DCD Weber set up and it stumbles in right hand turns - a serious pain. My new car has a Dellorto with a short manifold (not on top of the motor) and it's seriously faster than my Weber equipped car.
-I use the stock ignition, battery location, pulleys, fan, and a early oil cooler. I have a light steel flywheel but always wished I had gotten an aluminum one. I use a CF clutch.

Sounds like you've got a good plan except maybe for those wheels. The book that Jim Susko (g-Force Engineering) is WELL worth the $75.

the steelies i found are only 13 lbs each. do you know where i could find aluminum wheels that would be lighter? do you suggest i go with wider wheels? if so, what dimensions/backspacing/tiresize? i've been looking more at the g force tri link and panhard, and think i might go that route. with the miata torsen, don't you have to worry about not enough of the axle shaft going into the diff? i've got the 3.90 gears now, just thought the 4.10s would give a little more help to make up for the smaller displacement of the 12a. thanks

Do What slowautoxr Said he knows a little about CSP. I would like to find out what is special about those rear shocks if you dont mind. Thanks, Jimmy

Go with as wide a wheel as you can get, more rubber on the ground is good.

Wish I could be of more help, but I've never dodged cones, except for when that fine Aggie pavement comes up and the esses become one car wide. :D

I doubt you want to put 10" wide slicks on it, but I don't think you'd be able to cram that much in there, anyway. ;)

i'd like to know about the struts also, whats the difference. i think i could go with 13x8s, anyone know what size tire i would want to run on those, and any recommendations on rims? the rims i have been looking at are the mini stock steel ones from diamond. 13 lbs ea. didn't seem too bad, but if there are aluminum ones i can go with, i'll go that route. also, i did a little more research on the rear gears, and mine are 3.90s and the gsl-se would be a 4.07, is it really worth the upgrade?

Those 85-85 rear MR2 Illuminas are the same ones that Mazda Motorsports sells as the "IT" struts. Supposedly a bit heavier duty. I think you may need camber plates with these struts. I have some old Rotary Engineering camber plates and I had to take some shim stock to form a very thin sleeve between the bearing and the strut.

The new car I bought is Wendell Karr-Ake's old car. Finished 3rd or 4th in CSP several years ago. This car was set up with g-Force Engineering stuff. This car has 13x9 Duralites with 225/45-13 Hoosier Street TD's - a very very light tire/wheel combination. (He had 13x8 and increased the width to 13x9) I asked Wendell about the 4.10 gears and he told me what I posted earlier. This car also a Miata Torsen - you're going to need this or lsd. Just get something. If you don't you'll lose tons of time smoking the inside rear tire.

Speedturn is a G-Force guy also. He road races his very cool RX-7. The balljoint spacers he mentioned are not legal for street prepared though :(

edit:
Just did a little search on the Duralite's. Looks like they may not be available in 13" anymore. Looks like you Diamond racing wheels may have to do. If you do, be sure to get the right lug nuts.

will the 225/45 work with 13x8s? i think i'll stick with the stock gears, but go with the miata torsen. thanks for the ideas, i really appreciate it. please keep'em coming.

I'm sure it'll work. I've put 225/50-15's on 15x6 wheels (GS Neon ACR). Is it the best - that I can't answer. While I get used to this new car I'm going to put my 205/50-15 Azenis on it - of course I'll have to raise it a bit to clear the tires :(

On your list you don't have camber/caster plates - is that on purpose? The best thing you can do is get Jim Susko's setup manual at g-Force Engineering.

i forgot to add them, they are one of the first things i plan on getting.

225-45-13s work well on the 13x8 Diamond wheels.

Sticking with the 3.9 gears is a good idea. I actually considered going to that instead of the stock GSL-SE 4.07 gears when I went to 13s because I was running out of gear (2nd turning 8-8.5k rpms) on most courses. Instead I went to 225-50-13s in the rear. It helped, but I still run out of gear often. YMMV.

Sway bars: I/we (my co-driver did the work) found that you can modify the front bar and remove the rear bar altogether if you choose the correct spring rates. (you are pretty close with your first guess as far as that is concerned...400 fronts may be better) Get the G-force book www.gforceengineering.net it will tell you more than you can imagine.

Struts/shocks: The Illuminas are a compromise...they really aren't meant to handle spring rates over 300-350 lbs/in. If you have the cash don't hesitate to get the Advance Design shocks. However, the Illuminas will get you started with decent results.

Rear Axle: Get the panhard and tri-link. Again, everything else will just a be a compromise.

Just thought I would give you my input.

I'd skip poly bushings and go right to Delrin (Delrin AF to be specific).
Why not update to a 13b and run ITB fuel injection and a stand-alone?
I don't know your budget, but Kodiak makes pretty good wheels with CNC Aluminum centers and Al. shells. www.kodiakmotorsports.com The 13x7 Kodiaks we run are ~5lbs.
Good luck.

those wheels are awesome, but probably a little out of my budget to start. i'd like to update to the 13b, and even had a thread about it over on the 1st gen board, but again, budget. i figure if i can max out my 12a to the rules, it still will be pretty potent. i'm mostly concentrating on the suspension to start, then can move on to the engine. I don't expect to ever will the national championship in this car, so i don't want to blow a couple grand on stand alone/tb setup (plus my wife has a hard time with what i am spending to begin with, that would be a hard sell). i'm trying to stay under $5,000 total for the buildup (includes rebuilding the 12a)

Last weekend at the L.A. autocrosses, I talked to a guy who runs CSP. He said he took apart his steering rack and adjusted it, and was able to get all of the slop out of it. He said there are three adjustment points, though the factory service manual only says to adjust one of them. I guess the other two made the difference.

I'll try to get a lap or two in it and see for myself how it feels. I've driven in only 1 first-gen so far, and the slop in the wheel is very noticeable.

-s-

i think there is an article on mazsport about doing the adjustments to the steering

I don't know if this is supposed to be a street car also??

You may want to consider flaring your fenders to get some really big rubber under them. If you do this, your choice of wheels and tires will be greatly expanded. I did my fender flares with a piece of 2" exhaust tubing, a cutting wheel, some bondo, and a can of spray paint. The end result looked OK, but certainly not professional. It was a good deal of work, but cost virtually nothing. I was able to fit 225/50/15 tires on 8" rims when it was done, with no rubbing. The car was severely lowered with very stiff springs in the front.

Get the biggest stiffest front sway bar you can find :D

i want to stay with the 13s to keep the rotational weight down. i'm gonna go with the 13x8 rims as mentioned previously. thanks for the ideas though

anyone know how to get a repu to auto-x fast? i think i should put in a watts link or panhard for lateral axel location since the leaf springs don't cut it :)

I hope that is a joke.

If you're mechanically inclined and can fab up some stuff - Susko's book has some very neat ideas - including a little something on utilizing the stock front swaybar. The CSP car I bought has all the g-Force stuff on it. I'll let you know how well it works at the end of next month. How much is a front sway bar $120? Susko's book is $75 plus you get unlimited help from him.

jim susko knows his stuff up there at G force engineering. buy his book, it will really get you thinking. and he's been excellent with informational support with his products. his stuff is mainly for ITA road race stuff but is basically the same as CSP minus a couple of things like turn-in spacers.....

the book is on the shopping list (especially considering his shop is only like an hour from where i live). i will definately be getting in touch with him.

Not a joke. A bigger stiffer front sway bar worked very well for me for many years in CSP.

I guess I have a few questions then.

What spring rates were you using front and rear?

What if anything did you do about poor rear geometry? (watts link/trailing arm bindage)

In CSP (if you have the desire and or money) I think there are better ways to get a well balanced car than adding a large front bar. In all reality if you are changing springs and other stuff anyways the cost really is pretty even. If you are keeping stock springs and rear suspension geometry then I suppose a large front bar would be an ok compromise to counteract the binding/infinite roll rate in the rear.

Lots of good questions :)

I sold that car about 4 years ago, after racing it for about 10 years, so my memory about each detail may not be perfect.

The car was a 79 base model. The front sway bar was a "big stiff one" :) Front springs were around 400 lbs, with modified homemade coilovers and the car was very low. I had very little suspension travel. I had camber plates set at about 3* negative. The rear end had stock springs that had been significantly cut down to lower the rear. In fact, they were so short that I could jack up the rear of the car, and remove them easily with no tools. The rear sway bar was a stock bar from an 82 GSL. I had a limited slip rear end. The rest of the rear was stock, including the drum brakes. And of course, my cheapo fender flares to allow the 225/50/15 tires. As you can see, there wasn't much money available to modify this car.

It had twin weber 36's, dual fuel pumps, a header, and a custom exhaust. No cats. It was very competitive. I won many local season championships, and was in the middle of the pack at Pro Solo events.

I had to sell it to get the FD. I sold it to a local kid who didn't take care of it. I was very sad to find out that it had been abandoned somewhere with no engine, and towed to a junk yard. Stupid kid :(

The front bar in my black/white RX-7 is a Koni which is supposedly the biggest one you could get. Like adamc my front springs are 400# but my rear springs are probably a bit stiffer. The stock rear springs were 80# so unless you cut 'em in half (which would bring them up to 160#) you'd be a bit softer. Unlike adamc my black/white RX7 responded well to being raised from the very low condition it was in. My new autox car though is very very low. I'm going to have to raise it a bit though to clear my 205/50-15's.

Jack up the steering wheel and drive an RX7 under it. Sorry, couldn't resist.

Seriously, there was some info I saw on a mini-pickup site some time ago. Most mini PU's share similar characteristics so start there. Sorry I can't remember the name of the site.

I recall racing in 1987 against an SCCA "sport truck" with my IT car, and the truck (a Toyota) was damn fast. Not so much in a straight line, but it was great in the corners. Might be a another source for research.

Jim Susko has great info on this. The front roll center ends up below the ground if you go too low. (the reason for his turn in spacers I think) It will also move side to side drastically if you are too low. The only way to really know where you are at is to either buy a suspesion modelling program or to make your own.

I have created a mathmatical model of the suspension that has helped determine spring rates, anti-roll bars and ride height. Basically I can adjust all he knobs on the computer and figure out what my weight transfer is. Getting the correct balance front to rear is the key to getting a well handling, pedictable car.

I have found a happy medium on ride height so that I can stick my 205/50-15s on without rubbing. It is also pretty good when going to the 13s as far as weight transfer is concerned.

anyone know how you could leagally run a 13b in a 12a car? is it possible to do the swap, and what would be involved? can you run a 2nd gen engine (the rules say same model car in same class, and n/a 2gs are in csp last i checked)? i have heard that youhave to mod the mounts to install a 13b in a 12a, and as far as i kow that is illegal, just wanted to double check.

You have to run a 84-85 GSL-SE motor. You cannot legally run a 2nd gen motor. I'm not sure of all the details but you would have to swap the K-member in there as well. You can update and backdate for models on the same line. To make the 2nd gen motor work, you would have to change at least the front cover and engines have to be swapped as a complete unit.

thats what i thought, think i'll try to stick with the 12a for weight purposes, plus its whats in there.

i was looking on the g force website, and was wondering if the tri link can be run with the stock watts linkage? i know the panhard setup is said to be better, but was wondering if this would be allright to do (i might go to the panhard eventually, just want to work in small steps). removal of the upper links would really help with the binding issues, just curious how this might work.

I don't think that Jim Susko would suggest that you do that. He designed both of them to work together. I don't think you would be that much better off with just one or the other. Either live with it the way it is until you have the cash for both or do both now.

There are some ways to help the situation temporarily.

Carl at PB and J racing has a neat little how to on a rear end tweak that'll help you - sorry don't have a link but you should be able to do a search to get it. Basically you can do all the front end work and run the rear springs you mentioned and you'll have a good handling car. Mine was good enough for my small pond but I was beat by 2.5 seconds per day when I went to a CenDiv Divisional.

yeah, i saw his bushing mods on the site. i plan on doing that and running that way til i can afford to do the tri link and panhard. looks like the car will be built in steps due to costs. in a few years it will be pretty nice though. i can't wait.

I made changes in steps as well. I have a GC panhard I was going to try next on my black/white RX-7. The panhard rod and tri-link were pretty serious changes to my otherwise STREET prepared car - with emphasis on STREET. I'm glad this other car came along.

gothca, this car is gonna be mostly for racing, maybe a little saturday driving (and driving to the races until i can afford a trailer), but thats is it. i have a daily driver, so comfort is not a big concern to me.

ok, i've looked a little more into the rims/tires and would like a few opinions. i'm gonna go with the diamond 13x8s, but wasn't sure what backspace to get, 4" or 4.5." i have heard of people using both. also, i am stuck between 225 and 235 45/13 tires, i know the 235s will rev a lottle slower, but might help on faster courses, any opinions? lastly, i have heard that hoosiers are lighter, i was gonna go with kumhos, but should i go with the hoosiers to keep weight down? thanks

You may need a 1/4" spacer if you get 4.5" backspacing. I got the 4" backspace and have no issues. They do stick out pretty far though. Keep in mind I have a GSL-SE. I am not sure if the others are different.

Hoosiers are historically lighter then most other brands in the same size. If you have the cash you should get Hoosiers at least once. I really can't decide what my tire will be this coming season. I don't think there will really be a significant difference in speeds from the 235 or 225 in a 45 series tire. It will more than likely come down to money rather than weight or actual diameter.

ok, thanks. i think i'll stick with the 4" backspace. i'll lok into the tire prices, and see what looks best pricewise. i'll probably go with the 225s for the quicker acceleration

The 13x9 Duralights on my new car measured at a 4" backspace as well. Oh, non -SE suspension.

well, i looked on the tirerack site, and the hoosiers (A3S04) are available in the 225, not 235, and they are 157 a tire, the kumhos(ecsta v700, shaved) are available in the 235, not the 225, and were 128 a tire. anyone know what the weight difference between the 2 is? what to do, what to do.

Not sure about the weight difference but they're both radials so I would guess that they'd be similar in weight. If you look at the section width of the you'll see that Ecsta V700 (9.2" on a 8" rim) and the A3S04 (8.8" on a 7" rim) are very similar and the tire diameters are similar as well with the Hoosier being just a bit shorter (20.7" vs 21.1"). I've driven the Ecsta V700's (on a G Stock Neon) and found that they get too hot and then become greasy (at least for a two driver car). The Hoosiers are faster but more expensive. If you got the money...... get the Hoosiers. I've also been on V710 (on C Stock Miata) and like them. They're available in a 215/50-13......

ok, thanks for the info. looks like i might go the hoosier route, especially if its worth the extra money.

i had another thought. i got a holly manifold for a pretty good choice, and was thinking of going with the holley fuel injection setup (throttle body style). anybody run this setup, or see a car running this setup. i have seen them used on ebay for decent prices, and fuel injection will offer much better tunability than the carb. any opinions?

After autoxing a Neon and a Miata I had completely forgotten about the fuel issues with my RX-7. As my RX-7 got faster throughout the year - the limitations of my carb setup (or maybe my lack of know how) fuel issues have become a concern. Hopefully my new car - although not fuel injected - will not have problems. Fuel injection would be nice.

i decided against the fuel injection swap for now, the kit is like $1200, and i can put the money elsewhere. gonna go with the sterling carb/ported stock manifold setup