I've got an RX-3 that was set up for ITA racing but since it blew the 12a at TGPR we dropped in an S4 motor running megasquirt (149HPz with a terribly crushed header).

The extra 30 horsepower has really made clear our need for bigger/better brakes.

At one point we swapped in RX-7 struts but even with maxing out the camber plates we barely got any negative camber which corded a fresh Hoosier at Nashville's road course after 1 day. Has anyone come up with a simple solution to this? We've debated cutting the strut tower top and moving it inboard a bit, but we'd like to be able to return this car to ITA status at a later point.

Basicly we'd like to run the bigbore RX-7 struts in the front, possibly using the RE-speed front big brake brackets to use the 2nd gen 4 pot calipers.

Another idea we've been tossing around is to find a 2peice rotor for teh stock struts and possibly fab a caliper mount for the 4pots.

Anyone have any ideas, contact information of people who've done this, pictures, etc?

 

corded? shredded the tires? no spacer on top?

 

yeah corded as in wore through the brand new, only heat cycled $150 dollar slick down to the cords. I wasn't aware of the need for a spacer as the stock strut tube has been cut down to accept RX-7 sized shocks. all the dimensions between the two struts are the same except that obviously the hub/rotor are different and the strut tube is pressed into the hub/rotor assembly at a 2degree angle (towards the inside of the car) which if just stuck in the RX-3 causes a atleast that much positive camber.

 

Why not make a new tubular lower control arm about 1" longer and this might help with the negative camber that you're after..You could put the balljoint on a special plate thats not attached to the arm and slot some holes to give you additional adjustments, Basically you'll get camber/castor from a simple adjustment of the ball joint... About a year ago I had CAD drawings for all the necessary parts to mount a 2nd gen hub,rotor & caliper on an Rx2 splindle but I couldn't find someone to machine it for me... I passed the info on to Billy (ReSpeed) but I'm not sure what happened, but they never produced it.. Im sure with some fine tuning we could have gotten the bearing sleeve/spacer to work on an Rx3 with the stock spindles...
The racing store.com sells a brake kit for the rx3 but its mainly use in dragracing... Its made by Aerospace components and quite a few guys use them on their old skool rotors
http://www.theracingstore.com/index.php

 

I could have done it a lot better than this but i was in a hurry. A friend of mine use to run a first gen and he said that they heated the tubes with a torch and bent them until the strut would barely fit to maximize the camber.



By allenrx3, shot with E4300 at 2007-07-10

 

How much camber are you after? My rx3 has the rx7 gsl-se front strut with RE speed camber plates, I was able to get -2 camber any more that that I'll have to go with a coil over set up. The rx7 spring perch will hit the strut tower wall because the spring is to wide at the bottom. I thought about using a narrower spring so I can bring the camber in more, which mean cutting and welding the new tube in place.

 

The lower control arm solution was actually my first thought. THe only trouble with that is that the front sway bar is an integral part of it. Anyone know if a RX-7 swaybar is of similar size? I guess I'll have to dig out a stock one and compare.

How would with this effect suspension geometry? Obviously it will increase the track width. but do you have an idea as to what it would do with the bump steer or turn radius? I'm not too great with suspension design.

hmm that brake kit looks like something to look into. But it looks to be a side-grade in terms of stopping ability. Though i bet it's nice to not have to buy parts cars just for brake rotors.

I don't suppose you'd know where I could find those drawings? I guess I could shoot respeed an email

 

We're running somewhere between -2.5 and -3 degrees with RX-3 struts with about 1/4 to 1/2" left on the camber plates. Both strut assemblies have coilovers btw. With the RX-7 struts on the RX-3 and the camber plates maxed out we were getting somewhere around 0 and -.5 which isn't enough with the softer front spring rates we've been using.

Car is running I believe 275 or 250lb springs in the front and I have no idea what the leaf springs in the back are, I'd have to ask my dad. He sent them to a shop somewhere up north which made new leaf springs at the specified strength and ride height. They turned out well. The sway bars are ENORMOUS but I'd have to get under the car to get their diameter. In short we may be running a little too soft rates in the front that's allowing too much body roll.

The problem with the RX-7 struts was the car pushed a bit harder than usual and absolutely ate tires on the passenger's front. That track with RX-3 struts will put some pretty good wear on a tire, somewhere between 1/2 to 1/4 tread life, but definitely not eat a fresh Hoosier a day.

Edit: if it makes a difference the RX-7 struts are from an 84 GS

 

Im also running a 1st gen strut/brakes/coil over with RESpeed camber plate. Was too low and was eating my tires so I added a 1/2 aluminum spacer (copy of the stock RX-3 1/8" triangular spacer). I dont know how much camber Im running now since the RESpeed camber plate is not marked. Btw, my RX-3 is not a track racer like yours so Im not sure if it helps but it handles pretty well at the canyon.

 

Fabbing a control arm shouldn't be a real issue, my guy was charging me $600 for both and it seemed pretty high so I didn't follow up on it after that... Get some DOM tubing, weld it up then have a machine shop open up the ball joint hole to your exact specs because the tube might have gotten warped after welding...
What if I told you that there's a way to run a full 2nd gen front suspension on a rx3, that means Knuckle, brakes & struts, would you say im crazy?

 

I'd drive to the bronx and give you a hug... or maybe I'd think really hard about it. Please enlighten me. As a guess are you talking about a full subframe swap?

 

Hug, man bring a bottle of Johnny and we'll talk... nope its not a full subframe swap.... the answer lies in a ford, yep a bloody ford nahhh im messing with you... PM me, i wanna see some pics of your suspension

 

I'll go out to the garage and jack that mother up take a couple shots. Be warned. This car has been a race car for nearly 2 decades and it shows it.

 

While you poking around in the garage , check to see if you have an old rx3 balljoint laying around.... If you do, then please measure the diameter of where it gets pressed into the control arm and PM me with it.... Maybe on moday i'll pass by another chassis shop to see if i can get a quote on a custom arm... The hardest part of building the arm is the part where the swaybar goes... if that sway bar wasn't attached to the arm then i could have put in an adjustable sleeve in the new arm and this would have allowed more camber.. I was also thinking about replacing the stock swaybar with a straight, hollow tubular one that has splines on the end.... The splines will be connected to two linkages that would hug the chassis and allow more room for a wider tire, also the linkages will be bolted to the control arms... I hope im making sence to you here, but i have a mental picture of the setup and actual fitment of some of the parts
check this out...here you will see the hollow swaybar and the linkages (arms) im talking about...http://www.hrpworld.com/index.cfm?fo...ction=category

 

you has pm. We don't have any balljoints laying around. not sure if we even have a spare that I could measure out.

that's an interesting idea for a swaybar. It would be fairly nice to have a little extra room for those 225s we've been trying to shoehorn in the front.

replacing the LCA with a tube and heim joints like 13b-RX3 shows looks pretty straightforward, it's just where to mount the sway.

I don't suppose anyone has found anypictures of RX-3s with relocated strut tower tops? It shouldn't be hard at all to just move teh top inboard. The only trouble is making sure it's strong enough for that.

 

First off i must say that you're a crazy bastard if you actually went out to the garage at 2am to get those pics
That LCA is piece of cake, problem is the swarbar.... what if i told you that we could run a 2nd gen knuckle using a tricked out balljoint on a stock rx3 LCA , would you still think im loco?

 

it's only 1am here. I don't have much better to do. I think I'll walk around behind the garage and hunt down one of my 2nd gen struts to get a better idea of what your talking about.

 

I already got the knuckle to work on the rx3 LCA (well sorta), just need to fab a longer 2nd gen strut housing because it'll sit to low if i use the stock one.... either a 2" longer housing tube or cut the brackets off the bottom and put on some longer cnc cut ones.... if i change out the brackets on the bottom of the Tien coilovers then i can re-drill the 2 bolt holes to new specs to give me 1 or 2 degrees of - camber

 

comapring our coilover first gen struts and the second gen struts appear to be the same size spindle to spindle. How are you getting over the second gen struts being Front steer compared to the RX3 being rear steer?

edit: looking again, the shock area is indeed shorter on the 2nd gen. by eyeball it looks to be about an inch or two. but the entire strut assembly, top to top spindle to spindle is about the same size.

 

come on men, thats an easy one.... Put the FC right spindle on the rx3/rx2 left and you're set....the 2nd gen strut is shorter and can easily be altered to fit... Im thinking about making 2 plates that would probably be welded to the FC strut brackets to give me the extra 2" needed... stop playing around on the forum and go outside and figure out the thickness of the bal joint , its freezing ***** here in NY and all my R&D is on hold because my 7 & 2 is taking up precious garage space at the moment... My rx3 gets the step child treatment, it sleeps out in the cold

 

what dimensions do you need?

not sure I like the idea of the calipers being towards the front of the car. Ever production car I've ever seen has them towards the rear. I'd have to hypothesis that the brackets are made to withstand an upward force compared to a downward force. but Like I said I don't know much at all about suspensions. Need to take that suspension design class...

 

Watch out for ackerman problems when swapping spindles left to right.

-billy

 

I had the same problem with my old ITA RX-3. Dave Gilbert at DGEMotorsports.com came up with the front end I have on the car now. This is an option, though it is a lot of work. He took the RX-7 lower control arm and "attached" a rod end to the inside, allowing me to "dial" the bottom of the control arm out to regain the camber. He fabricated a bracket and welded it to the frame rail where the stock sway bar mounted and used the locating rod from a RX-7 with GForce spherical bearings. He used an off the shelf, aftermarket sway bar and arms, going through the frame rails and attached it to the strut itself.

If you are not running IT any longer, are you running slicks? With slicks you only need 1+ degree of camber; not the 3+ that is required for "treaded" tires.

I will pm you with photos, the ones I took are to big to attach.

 

I'm sorry I misspoke about the "slicks" i was referring to the DOT R-compound Hoosiers not the cantilever slicks. I've actually been curious about how well they'd do on the car, but I'm currently running in SM and I think they require a DOT tire (I only do Time trials/Hillclimbs as Road Racing is just too costly at this point in life). I eagerly await your photos.

 

Thanks for that tip, will be sure to pull out the old mason line and check to see if my tie rods are falling inline with the Balljoint & rear axle center line...

Billy what every happed to that CAD file i sent you? the caliper bracket to mount the FC calipers on the rx2 was the same as the ones you make for the 1st gen... The only thing you needed to fab was the bearing sleeve... Im confident that the drawings on that file could have worked wonders for the few old schoolers on here, because the person i got it from also built a few kits and they're still running around Australia with no problems...