racermike

Anyone else Rallycrossing a 1st Gen in Stock?

dazed_driver

www.specialstage.com

You should find lots of rally help there! 1st gens make REALLY cool rally cars, too!

racermike

Don't need much help (see sig.), and no time currently to go stage, and I go back to the '82 Reno International Rally (Millen vs. Buffum)..... Just want to compare notes / thoughts with fellow 1st Gen competitors. But let's add Prepared and Modified to the querry since that's where I'll probably head after this year's Championship.....but thanks anyway.
PS. Do YOU need a chasis to build so you can get away from the Yota toy??

dazed_driver

Not from St Louis, unfortunately. No money to ship/get/buy


Besides, I like my 86, haha

Good try though!

peejay

Not in Stock class, no.

Coming to the E.S.C.?

racermike

I have looked at it. In fact yesterday did the mapquest thingy, 7h 7m, est fuel $49 1 way. I would like to but I don't know if I'll have the car together by then, in fact a race to get it done by CO.. And it's the weekend between "Test Week" and the "Runoffs" too.... So I am torn. I also need tires, and depending on which car I drive - I need 13/14". Don't want to buy 2! sets. Both possible cars are Stock, 82 GSL / 85 SE. But I do see an eventual progression possible, and I figure hearing from anyone else experienced in the RX7, regardless of class, could be benefitial.

peejay

The front end desperately needs to be stiffer and even the power steering box is too slow.

I'm up to 200lb springs in the front and am hunting around for some 250s. Still running front sway bar.

Could probably use less spring with less power, I'm doing everything I can to try to keep both rear tires planted. Currently running WRC sized rally tires in the rear for max grip. Next step will be a huge one - figuring out how and where to mount a quickener. I will probably revert to a manual box with a 2:1 spliced in the steering column.

Of course, none of this is Stock class legal, although a stronger front sway bar would be.

racermike

Interesting. With all the consternation about "shocks", I'm wondering which way you went with them; and also tire size and allignment? It seems to me that pavement vs. not, requires some re-thinking about set-up, and I may be leaning in the opposite direction of you?

On pavement you could overwork the tires if you don't keep them both involved (front), but on dirt I have been thinking that the weight transfer is a good thing - helping the outside tire "dig" into the surface and get more traction by getting "below" the surface. I had already gone back to the stock bar of course (past) but now wonder about an even smaller one. My "adjustable" shocks were stiffer on the softest setting than the stock ones, so I wasn't concerned to return them. (I MUCH prefer the stiffer bar and shocks on the street)

I have also been thinking that the more narrow the tread on the front the better, as it adds more weight "per square inch" on the tire / surface interface. (This philosophy has seemed to work for me in Solo and street on wet pavement, as well as most snow.) I have yet to experiment with allignments but my thinking is for a good bit of toe out (I run zero toe on the street.) to help the front "carve" the corner. When I am doing what I want on the course, steering isn't too bad. When I get behind, 4:1 might not be enough and toe out may slow it even more in transitions.

All other things being equal, the LSD seems to make it harder to get the back end out compared to the open diff. I had last year. While it would seem that the widest possible tire on the back would give more forward push (good tread spinning fast), I am also questioning the benefit of getting the tires "deeper" into the surface with more effective weight per square inch too. I haven't had the time to pursue info from off road racing like SCORE, have you? It seems that they may opt for not so wide tires as well??

Are you having issues with getting the front to stick - - because of rear traction? Is the car rotating how you want? Do you know how much power you have available?

peejay

Given that there is no real range of adjustment possible, I just set for toe settings that make the car drivable with my street tires (225/50-15 BFGs). On my previous car I wound in three or four turns' worth of additional positive caster. Alignment settings don't make any useful difference.

On pavement the car desperately needs more negative camber and less rear braking. On dirt the camber seems fine but it needs a lot more rear braking. So I'm pretty much leaving it as-is, although I'm taking steps soon to raise the front roll center.

Kinda like riding an ATV or snowmobile. Or skis.

Softer means less weight transfer on that end of the car, not more. You'd want it to be stiffer for more dig.

As a rule of thumb, for dirt/gravel, narrower is for cornering and wider is for thrust. It's a balancing act because with wider tires you need more power to blow away the loose top surface to get to the grip underneath.

http://4.bp.blogspot.com/_v8LT6h9LIW...h/IMG_5866.JPG

Pic from Saturday - not sure if it's hotlinkable or not so I'm posting the picture as a URL.

Generally that's backwards - a limited slip makes the rearend more unstable under power while making it difficult to get the car to turn-in.

Playing with diffs and such is not Stock class legal BTW - any options must be complete with everything from its option package, no pick and choose - although you may be able to claim that installing an open diff was an approved factory warranty repair for noisy limited slips, if you're starting from a GSL or GSL-SE model.

In order -

Not really. In an ideal world the car will understeer under full power. Currently, if I can put the power down in a corner, I'm limited by the stock 3 turns steering. The only issue I particularly have is front wheel lockup under braking.

No. That's why I have a hydraulic handbrake.

Way too much Various methods of calculating power make it roughly 210 or so at the crank, although this is right on up there and most rallycrossing is spent in the 4000-6000rpm range in Second gear.

slowautoxr

iTrader: (6)

I have an '81 that I run in Prepared. It was put together with a bunch of used and leftover parts from my autox car and a parts car. When it became road worthy, it was almost perfectly setup up to the prepared rules.

slowautoxr

iTrader: (6)

To reduce understeer I was thinking about getting some camber plates. Currently I have some positive camber. I was thinking that some good negative camber would help. Instead of buying some, I could take a set out of one of my other cars and try it.

What and what size do you run for your rally tires? From the pics of this past weekend (east coast championship) you're running pretty big tires and larger in the back than the front. How did you make those big tires fit?

I used to fool around with the hand brake and I couldn't really tell if it made me faster. I've also fooled around with left foot braking and right foot braking. I LFB at autox but pretty much no longer do at rallyx. I found myself locking up the brakes (and going straight). RFB also transfers the weight to the front tires. How does that hydraulic handbrake work?

peejay

I don't think camber makes much of a difference on dirt.

That said, I have a spare crossmember and I plan on redrilling the control arm mounting points upward and outward a little bit, which will add a TON of negative camber (well, about one degree at ride height) as well as raising the roll center, which is what I'm after in the first place. It will also add some more antidive which may or may not be a good thing.

Because the control arm mounting bolts are rusted, I'm going to have to swap control arms at the same time, and the extra set I have needs ball joints, so this little project is going to have to wait until I have the cash for that. The fenders will need to be cut/flared as well, period. They're heavily rolled as it is and they still rub. Next step, Mk2 Supra fender flares.

Tire wise the front it's 185/60-15 'Kooks I bought from a Spec Focus dude locally, and 17-65-15 Z-72s in the rear. Used to run 65cm tires in the front too but that requires comprehensive restructuring of the inner fender area for clearance, which was not legal until recently. So, smaller tires in front. The big'uns fit the rear no problem, and the fender lips aren't even rolled.

At the ESC the car handled like a dream. It was extremely dusty and usually all I had to do was brake into the corner and the car would set itself up. As ruts developed it was just a matter of driving conservatively enough to drop down into them and then stand on the throttle. The only problems I had were on the second day's course which had a real a-hole section where in the fastest part of the course, there was a rise/dip right before a very tight section, and I coned there twice out of four runs. The second time after slowing down a bunch BEFORE getting to that section, which really bothered me because I lost a lot of time and hit the cone anyway. And the main problem I had was reading the first day's second course wrong and missing a gate 2 cones out from the start. Wham, 15 second penalty. That threw me off my game and I overdrove the second run on that course and was about 5 seconds off the pace.

I ended up placing 3rd. I was .6 seconds away from 2nd. If I hadn't driven overconservative the one time, or didn't miss the gate, or even just kept my cool and drove cleanly on the one run, I would have had 2nd in the bag. Oh well...

I mainly use the handbrake to keep the car from rolling at the start. To use it properly requires that you have the car's weight already transferred, which is hard to do since the car doesn't really drive by weight transfer like a FWD/AWD car but instead more drives by pitching it around. So basically I rarely use it since this season I haven't been on any courses that were not fast and flowing. Next year when S&M is back in the game I expect to need to use it, S&M has tight cramped courses and I used to deliberately upshift to 2nd before the tighter corners so I could drop it into 1st without matching. With the handbrake, I won't have to do that. I hope.

gracer7-rx7

iTrader: (16)

I've been dying to try rallyx. You guys are making me jealous. I've been contemplating a 1st gen or Miata to have some fun with. The FD won't cut it.

diabolical1

iTrader: (3)

^ i have nothing against the Miata, but for off-road adventures, wouldn't a Gen II Rx-7 be a better alternative to the Gen I?

slowautoxr

iTrader: (6)

If you have a 2nd gen, it's absolutely perfect. Unlike autox, I don't think there is a car to have. A rear engine car might have an advantage in the rear wheel drive classes but at this point in time, it really doesn't matter.

peejay

It's wider, which is bad. GC Imprezas demolish GD WRX/STI partly because they're narrower.

They're cramped inside, which is bad unless you're about 5'8.

The rear suspension looks pretty fragile, and is pro-squat.

The reduced unsprung weight in the rear does look promising, though. Not sure if it outweighs the disadvantages.

racermike

I haven't had time to respond here but I will soon, and with a little more data
Keep the stuff coming though, because I have a few different views I think; and I would really like this thread to help out current and future RX-7 Rallycrossers (including me )
BTW, National Rallycross Championship winning car in "Stock Rear" was a 1st Gen RX-7 - again!
Ist day write-up: http://www.scca.org/newsarticle.aspx?hub=2&news=3798
2nd day write-up: http://www.scca.org/newsarticle.aspx?hub=2&news=3801
Results: http://www.scca.org/documents/Rally%...nalResults.pdf

slowautoxr

iTrader: (6)

Congrats on the win Mike. Looks like you were in a different RX-7. Did the car perform well in the thin air? How'd you like the gravel lot? How tight was the short course?

You made a big move on day 2. What happened to the MR2?

wankeltrim

Looks like there are a big differance in european rallycross against yours witch is more like a rallysprint.
Watch this movie and go to 2min and you will see 2 rotary powered cars. One FB and one rwd 323 GTR both with 13B PP engines.
http://www.youtube.com/watch?v=yEkFV...eature=related

peejay

Yes that's a good way to put it, except the speeds are a lot lower and there is a greater emphasis on car control than on driving fast.

Maybe it's more of a cross between rallysprint and gymkhana than European rallycross, with a bit of folkrace/bilcross in since a lot of people just buy very cheap cars and throw rally tires on them, and when the car breaks they just buy another car.

eage8

iTrader: (9)

Me too, I'm planning to go to the first local one in march. I never got a chance to get out to one last year when I meant to.

I'll probably end up just being another guy in a Subaru though lol. I would take the corolla, but I think it's probably too low...

how bad are the ruts and bumps usually on the courses?