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-   -   Track only FD project (https://www.rx7club.com/race-car-tech-103/track-only-fd-project-137658/)

SleepR1 12-20-02 05:20 AM

Chronos you're not looking at the weight. 250 hp motivating a 1200-lb car is going to have some serious speed potential. GT2 is 460 hp motivating a 3200-lb car. Do the math. The D962R is <5 lbs per hp. The GT2 is <7 lbs per hp.

Now which car is going to be faster? The car with the least amount of weight per hp. Look at an F1 car. 1500 lbs and 750 hp. That's an easy one, 2 lbs per horsepower!

Don't be a Rikki's FD Rx7 is 2800 lbs and 351 rear-wheel-hp. Assume 15% driveline loss, and his car is ~413 hp at the flywheel. So 2800 lbs and 413 hp is <7 lbs per hp, and comparable to the Porsche GT2. Still--Don't be a Rikki will get slaughtered on the road course, he has no handling or braking potential, only acceleration which is good for exit speed out of a turn, but not much else. And his car will not make 413 hp consistently over 24-hours, knowing how fragile FD Rx7s are.

OTOH the Porsche GT2 has massive hp (made consistently), massive brakes, massive tires, suspension, and it's a Porsche (Daytona--Porsches reign supreme @ Daytona 24 hours)......

Chronos 12-20-02 09:38 PM

hehe, that's a road car...I was talking about the GT1 race car!

I beleive the Diasio 962R is 350hp too, so that's 3.5hp/lb

You're comparing Rikki's FD to a $180,000 car?! :D Try comparing my proposed Track only FD to a GT2, or better yet, a GT1: It was going to have about 600hp and run on race gas :)

For power mods: PPorting or Bridge, Ianetti seals, racing rotors?, a Dry Sump with oil passage porting, Dowl (spelling?) pins, GT35/40 kit, T51R KAIBB kit(pricey), T04R Kit, or possibly A-spec's new TT system if it could make high hp with that custom manifold...Rotaryextreme VMIC (good for 600hp), water injection system, dual monster racing oil coolers, exhaust, intake, etc. etc.

For the chasis: 13" AP racing rotors (or maybe Ti or CF if I could find them), Penske racing suspension, Ti Rollbar (I could make this myself), Rotaryextreme Widebody kit with 11" road racing slicks in the front and 12's or 13's in the back, all weak points in the suspension upgraded to stronger units(upper/lower control arms, toe links, etc...), racing tranny (I've seen a 6speed DOG engagement for the FD at 6k, but that's kinda steep), twin plate racing clutch, custom motor mounting...and maybe even a tube frame (I've done no research on this yet)

I would immagine with all that HP and that kind of grip all the weak points in the FD chasis would also need to be upgraded to stronger units as well. Did I leave anything out???

Btw, anyone know how much a tube frame FD weighs?? I'm sure it's still substantially more than a Diasio...

Mr. Stock 12-20-02 09:50 PM


Originally posted by Chronos
Did I leave anything out???

Yes. A Mazdaspeed body kit a la Crashunit:D

Chronos 12-20-02 10:36 PM


Originally posted by Chronos

Rotaryextreme Widebody kit with 11" road racing slicks in the front and 12's or 13's in the back...

That's the RE Amemiya Widebody copy which retails for 8k...

SleepR1 12-21-02 09:36 AM

This sounds like the "Leave It To Beaver" episode where Eddie Haskell brags to Wally and "Lumpy" about quitting school to work at the local auto garage; Eddie buys a bunch of expensive stuff (including a cool convertible) BEFORE his first paycheck even arrives.

As it turns out, Eddie was NOT a very good gasoline attendant, and Wally, Lumpy, and Beaver don't have time to hang out with Eddie because of all their after-school activities. Eddie begins to miss his schoolmates, and winds up BACK in school. Eddie even gets his old job back with the basketball team as the towel boy :)

Sounds like the best investment a young man can make for himself, is completing his education :)


Originally posted by Chronos
I ...the job I'm looking at (I don't even have it yet...) pays around 4800/month <SNIP>. If I get the job I'm taking a year off of school to accrew money and invest it into racing and/or moddifying my street car. <SNIP>

Chronos 12-22-02 02:27 AM

haha, that's very funny...I think there's also a difference between $0.50/hour and $30.00/hour too :) And who said I wasn't completing my education??? I'd just be taking a year off.

BTW, why don't you reply to my "on topic" post if you're taking time to post a comment??

Anyone know how much tube frame FD's weigh???

r0t0rhead 12-22-02 06:43 AM

How much does a tubeframe RX7 weigh? The chassis? The complete car? Or the car as raced? Depends upon the rules- GT cars must meet minimum weight determined by the sanctioning body-ie SCCA, ALMS etc. SCCA GT1 spec for a 13B RX7(non-turbo) is about 1800lbs.
Turbos are not allowed in any SCCA GT spec classes-that's why turbo RX7's aren't running. The FD series is still eligible in Speed Challenge & Grand-AM series- but these must be production based cars-non tubeframe, also the rules will dictate the size of the turbo AND the amount of boost, motor mods etc. Before you do anything you have to get a complete understanding of the rules. In both the Speed Challenge, and Grand-Am series-ported engines aren't allowed and the turbos specified are the stock Hitachis- boost is limited to 13psi including boost spikes, they also require that their boost pressure recorder be installed at the track by the tech inspectors. Some competitiors have had rules concessions to allow replacement of the twins with a large single turbo- but at 13psi its not much gain- besides if they started getting competitive they would be hit with a weight penalty.
American Lemans Series (ALMS) forget about it- Yes you could probably enter your dreamcar here, but you better bring about $2 million to run a season.
NASA will let you run what you brung- but the liberal rules approach will put you in a class where you are constantly spending money to stay competitive, or racing by yourself

SleepR1 12-22-02 10:41 AM

chronos, I was staying on topic. I commented on your not-yet-defined job prospect :) 50-cents-per-hour was a good wage in 1957 :)

Excellent point Bryan. chronos will need to do a thorough research of the rules requirements.

IMO, I think the rules constraints is why most FD Rx7 owners don't race with any santioning bodies. There's no place for them to run, except drivers eds and open lapping track events

Believe it or not, the competition is quite fierce in drivers ed and open lapping events. Just because you ain't racin' tire-to-tire, don't mean you ain't racin'!

r0t0rhead 12-22-02 04:44 PM

I agree- track events offer a lot of track time for the money, and plenty of time to learn the car and track, much more so than an SCCA race weekend. We are planning to organize some events at VIR for our customers this year with some pro drivers to help out. Regarding the FD's competition potential-We were planning to build a FD for Grand-Am in 2000 with a spare setup for SPEED Challenge- but even with some concessions from the organizers (larger turbo & better brakes) we determined the car would be hopelessly uncompetitive. Although we had some sponsor money lined up it just didn't add up to go out and spend a minimum of $90K to run a limited schedule and still not have a chance to make the podium-unless some major failures occured. Financially it made no sense at all.

Chronos would really be wise to rent an ITS car and run a few races where the fields are 40+ cars and extremely competitive. Speed is somewhat relative and its hard to explain to the uninitiated the difference between wheel to wheel racing and drag racing, or auto-X. It still amazes me that people consider an auto-X a race- fun for a bit-yes but shagging cones offsets the brief pleasure. I'd rather crank up the Playstation. Drag racing? Toss me the Nintendo.

SleepR1 12-22-02 05:25 PM

Bryan, I couldn't agree MORE :)

FWIW Putnam Park opens 2003 with our MDC event on Saturday March 22. If you're in the area, perhaps you could have you join us in the new D962R? Or you could run what you brung :)

Chronos 12-23-02 07:13 PM

haah, that's very funny with the video games...I think I would seriously rather play Gran Turismo 3 than enter a drag race too!

NASA sounds like the place to play for my purposes...

r0t0rhead, do you have any info on the possibility of giving the Diasio an extra 100hp? Would it be mechanically and functionally possible given the rest of the chasis?

Also, I was asking how light I could get the FD with the tubeframe...I'm not really interested in racing any other series than NASA since they'll never let the car run to it's limits. As for American Le Mans....hrm, maybe after I'm a millionaire ;)

SleepR1 12-23-02 10:45 PM

Radical Motorsport SR3
 
I have to admit, this car looks impressive. Gorgeous Pilbeam body too!

http://www.radicalmotorsport.com/

I just got their brochures in the mail.

The Supersport is available with a 1500-cc Kawasaki 252-hp motor!

This car is all the rage in Europe. There's an entire race series dedicated to this car.

There are a few west coast Radical Motorsport owners with the Tracksport model; they just rave about how wonderul the SR3 drives.

Chronos 12-24-02 05:45 AM

haah, the Diasio 962R would rip that thing a new hole!! 253hp vs 350hp? :owned:

r0t0rhead 12-24-02 07:48 AM

Yes the Radical was one of the targets for Diasio- I've driven a Hyabusa powered one with about 240 hp and I was very impressed-it is indeed a high benchmark but I believe the 962R will be competitive in the right hands.
For a SCCA national championship -you still have to beat Ben Beasley's rotary powered racer, and that's going to take some serious effort by any team.

Chronos- the SCCA legal version of thew Diasio is required to use a 12A bridgeported engine which produces 250hp. The chassis was designed to handle much more power for customers that are looking to run a turbo version in track events. The 350 hp 13B turbo version will be achieved at conservative boost levels for reliability-of course more power can be extracted by increasing boost pressure.

Chronos 12-24-02 05:53 PM

yep, the difference between 350hp and 450hp in a 1075lb car and a 2780lb car is quite a bit different :) I can't immagine how crazy that thing would be at such power levels...


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