Utlimate RX autocrosser
O.k., a little thought experiment...
You have in front of you a first gen RX-7, unlimited tools, and $10,000. Your mission is to make the ultimate RX-7 autocross car. No rules, no limits. What do you do? Engine? Trans? Rearend? Wheels/tires? Suspension? |
Ditch the 1st Gen and start over with a better platform. Sorry, I'm just honest.
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If it weren't for the title, I'd agree with Chris.
But I don't autocross, so I don't know the answer. ;) |
Alright, smartassing aside, I know that it is not THE platform to have, but it's part of the deal.
If it helps, it's not real money being spent. Just a thought experiment. |
13b turbo
slicks fiberglass lexan cage BP class? |
Um, build a car like mine:D Honestly the 2nd gen platform has won 6 or 8 national championships in FP, and BP. Those cars were like mine, but half the power. I have NO lag in my current set-up(PT67 .81 P trim), although I would use a slightly smaller turbo hotside, like a .70 divided, instead of a .81 un-divided. Get a GTU shell, do a TII conversion, and widebody, then bolt a TO4R with a .70 hotside .70 compressor to it, viola BP national champ(Oh, and you'll need a driver ;) In terms of the widebody, just prep it for thye flares, but skip them to keep cost, and weight down(if allowed to have exposed tires in BP). Carl
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Now, since you are using a first gen, Buy an old GTU/GT2/GT3 1st gen, turbo it, and go play
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Thanks!
There is a possibility that the car will be a 2nd gen, not that this is anything other than a thought experiment ;) Where can I find more detailed spec on your car, Carl? Just to make sure this thread stays interesting, would I be better of with, say, an LS1? |
Originally Posted by Feds
Thanks!
There is a possibility that the car will be a 2nd gen, not that this is anything other than a thought experiment ;) Where can I find more detailed spec on your car, Carl? Just to make sure this thread stays interesting, would I be better of with, say, an LS1? |
The LS1 will completely screw up your handling (see sig) ;).... Plus on 91 octane I only make 500hp with about $3500 in upgraded parts into a stock LS1 shortblock.
Ahem.... |
Mark, See you at the track Saturday right??? Never said It would screw up handling, your sig says 439, not 500+. My motor can be had for ~900.00-1200.00. But enough of this, give me one weekend at the track to sort the car(one weekend), and I'll meet you at Thunderhill on 8/18 for the ultimate shit talkers challenge. BTW, you don't have to buddy up wih the editor to get into this one;)
PS all of the above is meant in fun, nothing more(yea right) |
we are all car enthusiasts and talking sh*t is half the fun
My motor can be had for ~900.00-1200.00... don't forget to add turbo, exhaust manifold, downpipe, wg, fuel management, injectors, tuning, fuel pumps.... ohh yeah... did I mention tuning and having to fly guys in from around the nation to do it. ;) I'll be at Infineon Aug 6th.... I still have to learn my car as well. Coming from 140hp FC to a 500hp FD takes more than a few sessions at the track. |
Originally Posted by gnx7
we are all car enthusiasts and talking sh*t is half the fun
My motor can be had for ~900.00-1200.00... don't forget to add btw, I'm riding in both of your cars at Infineon. Carl, I also decided if you want my weekend you will need to let me drive your car at least one session over the weekend :D Don't worry, I've turned 1:44's all day long at Infineon and gone through turn 10 @ 115+ (in Star Mazdas ;) ). |
I know what you mean, my car has never seen the track, or theb street. The suspension, turbo set-up, aero, and everything elso on the car is completely untried, never tested/proven etc. For all I know the brakes do not even workZ(note to self, test brakes before track day) The car may have too large a frontal opening, too small a hood opening, the rear bumper is more like a parachute than a bumper, you get the idea. I think it will take me a year to sort this car out, hopefully I do not crash it(very many times) before it runs right. So when did you bump the FD up to 500rwhp? How much does the car weigh? BTW, this is on topic, the LS1 FD has posted some very nice numbers to be sure. It's been a year and a half since I hit the track, building a car sure takes longer than buying one... On that topic, most of the really good Prepared class cars are Pro-built national caliber retired race cars, refitted for AX. Carl
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Originally Posted by RX-Heven
$2000 heads, $1500 headers & custom exhaust, $500 cam, fuel pump, transmission, pricey conversion kit that breaks, still needing someone else to tune it so it can idle @ 2000 rpm and still run to hot on a real track :D
btw, I'm riding in both of your cars at Infineon. Carl, I also decided if you want my weekend you will need to let me drive your car at least one session over the weekend :D Don't worry, I've turned 1:44's all day long at Infineon and gone through turn 10 @ 115+ (in Star Mazdas ;) ). Sign a 30,000.00 promisory note(or the title to the 20B, and 10K), and you can have 3 laps, maybe more if the car is working right. Basicly, I do not know if anything will work, if it works right you are welcome to drive it a little, if it is behaving badly, or the handling/braking is unpredictable, then I'd be a little concerned. BTW I think NASA already made the change in registration;) |
I'm starting a new thread so Feds can have his thread back:)
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Thanks Carl...
So there is an aftermarket EMS in your car... I don't know if I will have time to tune. I guess that makes another restriction: Throw-it-together-and-flog-it prefered... but if you could put together a parts list for your motor, I'd apreciate it. |
Step 1: Sell first gen RX-7.
Step 2: Buy STS 2 Prepped Miata for $4000-$5000 Step 3: Go to Evolution School 20 times Step 4: Go to 40 autocross events each year Step 5: Your 10,000 is gone before 1 year of racing, work a lot to make the rest to support 8 more years of racing Step 6: Now any car that is setup right for a class becomes the ultimate autocross car when you hop in the drivers seat. Autocross is entirely driver, I had Karl Coleman drive my car at an event not too long ago and he hopped in my nearly stock Miata on street tires and was 1.5 seconds off the fastest time during the NON-Stock half of the day. Thats with pretty competitive prepped SM2 Miatas and all sorts of stuff and he said my car was handling bad because he had to counter steer alot. |
Originally Posted by Carl Byck
Um, build a car like mine:D Honestly the 2nd gen platform has won 6 or 8 national championships in FP, and BP. Those cars were like mine, but half the power. I have NO lag in my current set-up(PT67 .81 P trim), although I would use a slightly smaller turbo hotside, like a .70 divided, instead of a .81 un-divided. Get a GTU shell, do a TII conversion, and widebody, then bolt a TO4R with a .70 hotside .70 compressor to it, viola BP national champ(Oh, and you'll need a driver ;) In terms of the widebody, just prep it for thye flares, but skip them to keep cost, and weight down(if allowed to have exposed tires in BP). Carl
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Originally Posted by Icemastr
Not sure if you are talking about Solo II classes or club racing classes but I have a feeling your car would not do so well on an autocross course.
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BTW, the fact that someone has to "countersteer, means simply that they are over driving the car for its existing set-up, that is never the fast way around, so, obviously you cannot even comprehend what this man was trying to explain to you, and/or, most likely the guy thrashed your poorly set-up car because ther was nothing else worth doing with it. If it's all driver, then why do national champions bother to buy new cars???? why is each class generally dominated by one or two models? It takes both, without one or the other, you are an "also ran". What is it that you "instruct", maybe you can help us out on some of our questions regarding set-up. I have 16x11 slicks in front, and 16x13 out back, my suspension geometry is otherwise unchanged from stock, what will happen to my scrub radius? Thanks in advance for your knowledge, Carl
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Where did you go Mr. Ice???
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Damn Carl, don't let anyone tell you your car sucks ;)
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Why was the person who drove my car having to countesteer? Because like I said the car wasnt handling properly, the car was setup decently but my alignment settings had become loose since that last time I had them done as I found out when recently having the car aligned, my toe on the passenger side rear tire was 1/16 out when previously the alignment had been set to 1/16 total toe in and was handling great a few weeks before when Karl drove it. I think this has to do with the bolts needing to be replaced which happens on Miatas. Karl is a good enough driver that he can hop in just about anything and push the car to the absoloute limit, the course was heavily biased in left turns which would cause the right rear to want to continue swinging out. Because he would push the car he would get right to the limit of the tires and the rear would begin to swing out just a bit too much he would give it a slight countersteer, to put the car back into line. If I am missing something or I am misinformed please explain as I am always learning. Autocrossing is all driver, why do they buy new cars? Because new cars come out and and classing is always changing so when one new cars become more dominant the people who race stock class especially buy those cars to be competitive nationally and in regional PAX classes. Not all classes have completely dominant cars but many do. Someone who is a great driver can hop in a car that is not the car to have in that class and beat a field of mediocre or even pretty good drivers. However when it comes down to national level competition in autocrossing the times are within hundreths if not thousands of each other and the slightest difference in a car can make the difference. I didn't specify why I didn't think your car might not be so competitive at autocrossing and maybe I should have. The thing that comes to my mind first is the turbo, although you have a great torque and horsepower curve this is not everything on the autocross course. Doing a quick dyno comparison between a dyno I found of your car, not sure what PSI it was at your peak HP was around 450 so I am sure you can push a bit more, your car was making 45HP less at 3400rpm, 20 less at 4000RPM,and 30HP more at 4500 RPM and 50-60 more the rest of the way up. With your 500hp graph you would probably be a bit over 100HP more from 5000RPM on up. I will say your engine makes power quick compared to other smaller turbos such as a GT35R graph I also compared where your car was making 50 more HP than the GT35R even at 3500RPM. This gives you a huge advantage on the track since you will probably never be below 4000rpm, however on an autocross course boost/throttle response then max torque across the powerband is most important. A FMIC, large piping, and a large turbo greatly effect this. You claim the car has almot zero lag, I have never driven your car so I don't know how the boost response is on the car but common sense and experience says that a bigger turbo is going to respond slower than a smaller one. I am sure you launch at a high enough RPM that you always have positive pressure once you start racing on the track except for when you are breaking and coming out of corners. I have seen and experienced throttle response with naturally asprirated and forced induction engines because my area of competition and interest lies in the SM2 class which has 3rd gen RX-7s, Z06s, and Miatas all as the main contenders. I have codriven and compared results of a few of the different setups, 450rwhp corvette, sequential twin turbo FD with slightly enlarged ports and upgraded turbos tuned for max torque and spool up, postive displacement supercharged 99 Miata, GT28R miata and T3 super 60 Miata. When you have 4 times the steering inputs or more of a road course and very tight boxes to power out of, the disadvantages of a turbo become painfully apparent a lot quicker then on a road course. Comparisons between FMIC and SMIC for the FD have found the amount of time it takes to fill up all the charge piping and the intercooler makes a substantial difference in times alone. There are a few more things I could point out but they are easily changed but the point is you built your car for the track, some of its features, brake pads, roll bar, larger turbo,larger porting (not sure what size your ports are), FMIC are all things that are not the best for an autocross course. As far as your suspension goes I am sure that is all set very well and could do very well on an autocross course, but is your car going to go out and be nationally competitive in a class? That would be my definition of an ultimate autocross car. I do not know what kind of cars there are in the class you would compete in since there is only one car in my region that I have seen regularily race in a prepared class. Autocrossing isn't quite so fun to me when there isn't anyone to compete against either. I could be wrong on the scrub radius since I don't know much about since have only raced stock classes until the past couple months where we can't change offset or rim width anyways but if your suspension geometry and wheel offset remain the same I think your scrub radius would stay the same.
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Originally Posted by Carl Byck
Not to sound to snappy, but you have NO CLUE as to what you are talking about. My suspension, car weight, and all other elements pertinent to whether my car would perform well at an AX are essentially identical to two cars who, between them have more than 8 national Solo II, and Pro Solo championships spanning almost ten years. ....Regards, Carl Byck
-Andy |
Originally Posted by AMRX7
I wouldn't be so sensitive Carl. You've obviously done alot of research and built a nice looking car. However, you might want to wait until actually autoxing the car before saying it is great. On paper your car might be the same or better than previously successful BP 2nd Gen cars, but you might find the major power you're making would need to be dialed back on a little autox course. Anyway, it would be nice to see your car in action. The American Autocross Series runs in the central valley (near Merced) and typically sets up courses that your car would like (as opposed to low grip small courses in the Bay Area). www.americanauto-x.com.
-Andy |
How about you find an event where Andy Mckee is going and see if you can get him to drive your car during a fun run or something to compare times vs. his car on the same course or vice versa and see how yours stacks up against his with the same driver. It would be interesting to see the comparison and the feedback he gives on the throttle response, braking, and handling of your car compared to his. I don't know if you know him but he is on the forum I think, just don't remember his username.
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Originally Posted by Icemastr
How about you find an event where Andy Mckee is going and see if you can get him to drive your car during a fun run or something to compare times vs. his car on the same course or vice versa and see how yours stacks up against his with the same driver. It would be interesting to see the comparison and the feedback he gives on the throttle response, braking, and handling of your car compared to his. I don't know if you know him but he is on the forum I think, just don't remember his username.
First, let me apologize for snapping back. I am not suggesting my car would be nationally competitive as it sits. I was mainly making the point to the original poster, that a TII is a great platform, and that it had won many national titles in several different cars with at least five different drivers. Not sure when Mckee will be around here, but Derek Butts DSP champ is local, and I think there are a couple others in the region. I will likely make some American Autocross events in Merced, there will amost certainly be Nat. level drivers there, and it would be neat to see what a top driver can do with the car. I also have a nearly Nat level guy that runs locally, but he is driving an EVO, so it would be VERY different for him. Anyway, what is your name, and where are you out of? Thanks, Carl |
The original topic of this thread was ultimate RX autocrosser. You said build a car like yours sort of half jokingly. I wasn't saying the 2nd gen isn't a good platform. I know it can be a pretty competent autocrosser, ultimate? Well I would have to give that to the FD at the moment since the only class where I see that RX-7's are winning nationally are the FD's in SM2. I don't pay attention to every class though so there might be some others where RX-7s are dominating nationally. First gens seem to be able to do pretty well in CSP though. My point for getting to test your car against Andy Mckee's is to see how the time of your car would compare to his SM2 RX-7. From the info on your car it sounds like your suspension would be a really good setup, but like I pointed out a lot of the stuff you have done regarding power, brakes, etc. you would want to be different for autocross. In my experience, nationally competitive drivers, even if they have only raced a CS miata or slower car before can hop in a high power car and drive it very good, because they are still good drivers. They won't be able to get that last 5-10% out of the car without a lot of seat time, but they will be able to drive it fast still. I live in Washington state right now and compete in the NWR-SCCA as well as three local club seasons, WWSCC, BSCC, and SSSCC as well as national SCCA however I am not all that great of a driver yet. I am the novice chair for one of my local clubs that does 10 events a season and am a instructor for 3 novice schools held around the region every year. I won't be racing in California until next year when I go down to the Atwater NT, Atwater Pro Solo, and San Diego NT, that is if my girlfriend and I both get competitive co-drives. She probably already has a multi-national champion driver who is buying a new competitive car next season she will probably get to co-drive with since she is better than me. - Quentin Christensen
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Originally Posted by Carl Byck
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First, let me apologize for snapping back. I am not suggesting my car would be nationally competitive as it sits. I was mainly making the point to the original poster, that a TII is a great platform, and that it had won many national titles in several different cars with at least five different drivers. Not sure when Mckee will be around here, but Derek Butts DSP champ is local, and I think there are a couple others in the region. I will likely make some American Autocross events in Merced, there will amost certainly be Nat. level drivers there, and it would be neat to see what a top driver can do with the car. I also have a nearly Nat level guy that runs locally, but he is driving an EVO, so it would be VERY different for him. Anyway, what is your name, and where are you out of? Thanks, Carl Hi Carl, The TII is a proven platform for BP as evidenced by the Tripoint car and Steve O'blenes' car were both winners. However, I think that the FD is probably a better platform, it's just no one had taken the time and money turning one into a proper BP car, yet. That's changing as Jeff Kiesel from San Diego has put a tremendous effort into his FD. It was pretty amazing last year even with some serious problems, and if he gets all the new work done before Nationals this year I think it will be something to see. In any case, try and make the Atwater (AAS) events if you want a real autox comparison. Not too many higher prepped cars go to the Bay Area local events as the sites are too bumpy or gravelly. -Andy |
Originally Posted by AMRX7
Hi Carl,
The TII is a proven platform for BP as evidenced by the Tripoint car and Steve O'blenes' car were both winners. However, I think that the FD is probably a better platform, it's just no one had taken the time and money turning one into a proper BP car, yet. That's changing as Jeff Kiesel from San Diego has put a tremendous effort into his FD. It was pretty amazing last year even with some serious problems, and if he gets all the new work done before Nationals this year I think it will be something to see. In any case, try and make the Atwater (AAS) events if you want a real autox comparison. Not too many higher prepped cars go to the Bay Area local events as the sites are too bumpy or gravelly. -Andy |
in reply to people saying carls car wouldnt do good at auto-x BS!
huge tires and light car. my friend in az had a pretty stripped fc, i think like 420rwhp and 275 dot slicks or something like that. his car was one of the fastest out there all day at autox, only a miata and a couple z06s, i think autox is the most of what he races his car in, could be mistaken though. |
*sigh* I love the trash-talk and over sensitivity, this is a fun thread.
I'll let Jeff Kiesel know that he's got some competition coming. :-) I'll see him and Steve O'Blenes this Sunday (he's now driving an STU M3). From what Steve and Robert (codriver several years) have said in the past, his car made too much power anyway to be really usable in Topeka. Believe it or not, they ran the off-the-shelf AWR/Mazdaspeed ITS suspension for two years before having Guy build them some nice shiny suspension bits. BP is a very difficult class, as money and horsepower (ala Kiesel) don't always = winning. There is no guaranteed formula in Solo racing, even if the odds are heavily stacked there's always a raincloud in Kansas that'll fix that hehe. Good luck this season everyone, and keep hitting those Evo schools and practices...no matter the horsepower, we ALL need them!! Back to the original thread, a well-prepared CSP 1gen car with a fuel injected 13B would be my best bet....again, you don't have to chop a car apart or put a V8 or turbo in it to make it go like stink around an autocross course. Bob Mosso in his '81 used to do quite a number on the current CSP ProSolo winner's car (Schenker's miata as driven by Eric Clements) and certainly a top-10 PAX car/driver combo in the ultra-tough Cal Club Region. |
I see alot of bad advice here and only a few good ones
I agree with Dave turner get a 1st gen whatever year you prefer. prepare the chassis have someone build an NA 13b within the rules of the class you want. ive ridden as a passenger on a few 200+HP FB 13b's that were street prepared and were ungodly fast with some manifold work and fuel management. but some 225/45/13 hoosiers or whatever tire you like along with the suspension to make it all work and have fun. fun is the important part here. |
The mods you said you want to do are the good ones. For the engine, I would have a heafty street port, with a second gen turbo added on, and a supercharger from a Ford Thunderbird SC, with a full exhaust system and maybe twin mikunis. This would probably cost around 5k if you did the work yourself. The rest I would put into suspention, cage, and tires.
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DaveTurnerMotorsportsagain, you don't have to chop a car apart or put a V8 or turbo in it to make it go like stink around an autocross course. Bob Mosso in his '81 used to do quite a number on the current CSP ProSolo winner's car |
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