Barwick

I notice there's three choices available for the E-Prod class:

engine, chassis, min weight (with driver):
12A, first gen, 2100 lbs
13B, first gen, 2300 lbs
13B, second gen, 2500 lbs

Which is the optimal setup? The first gens obviously have their benefits/drawbacks... offhand what I can think of are:

Benefits:
Lightweight
Cheap as crap to find parts for
Easy to work on

Drawbacks
The patented "wonder steering" system (I wonder where it's going to steer next?)
Solid rear axle
Fairly old design
Not the best aerodynamics for lift, especially at high speed


The FC has some too:

Beneftis:
Stock 13B (S5 anyhow) puts out 160 hp compared to the 130-135? of the 13B first gen (although in E-Prod this shouldn't matter because you can street port, use S5 rotors if you wanted (rotors are open in E-prod), and change to another manifold if you use a carb.
Independent Rear Suspension
Supposedly great aerodynamics
Newer design
Designed to rival Porsche's 924 (or 944?)
More higher end aftermarket parts available

Drawbacks:
Much heavier than FB's
Not as easy to work on as FB's
Much more expensive than FB's

I'm sure there's more either way, but the question I've got for you guys is this:
I'm probably going to start in ITS (or IT7 if I get a 12A first gen) and keep my eyes on heading into E-Prod once I want to start going national. Which is the "fast" car that everyone runs in E-Prod? And what is the "fast" setup that everyone runs on that car/engine? Which motor, rotors, housings, etc.. if you know?

christaylor

1.8 Miata in EP. It's already kicking ***, and I don't think very many people have fully developed the 1.8 yet (a few, but not everybody). If I was building a car to win the Runoffs, it sure as hell wouldn't be a rotary... and I love 'em.

No, that stripped down Miata sitting behind my shop isn't for EP! I swear!

Barwick

I saw that a miata won the runoffs, but I also noticed that there were a ton of RX-7's. I definitely don't want to freaking have a miata, I'm so sick of seeing those things...

I see there was a good mix of first and second gens at the runoffs in E-Prod... even a convertible (which I think would actually be the car of choice, as opposed to running a coupe with all the windows down (which would probably cause more drag than just having a completely open convertible?))

maxpesce

That convertible belongs to Dave Lemon of MAZDATRIX - iirc it actually started life as a coupe and had the top removed for weight reasons - it is actually hard to build a second gen down to the 2500# weight limit. expecially so the factory convertables that have about 100# of extra steel in the chassis.
the major disadvantge to running 2nd gen RX-7 in e- production is that they have to give 200# to the Miatas while running on the same size wheels & tires, and do to the fact that the Rotaries have to run stock style porting (ie 6 ports, no Bridge or Perif. intake porting allowed) they don't have a big HP (if any) advantage over the Miatas.

That said I think the 2nd gen is still a better choice for EP than either a 12a or 13b first gen because of their far superior, suspension, steering and brakes.

most the first gens are moving into GT-3 where they can build full tube chassis, run perif port motors, and upgrade to better steering, brakes, and suspensions.

MPM

Actually Dave Lemons car did start life as a convertible.

http://www.mazdatrix.com/faq/epconv.htm

DriveFast7

iTrader: (1)

Bob Neal's 13b 1st gen finished 4th. And this was his first time driving at Mid-Ohio too.....

Barwick

man, I can't wait... there's got to be some good stuff coming down the pipe for rotaries in E-Prod... I'm thinking of developing of custom high-compression rotors and see if that changes things at all.

speedturn

iTrader: (1)

a 13B first gen would be the way to go.

Almost all road race tracks are very smooth, and so an IRS is not worth the 200 pound weight penalty.

As far as the 1st gen "wonder steering ," well it does wander around on the straights, but once the suspension is loaded in a turn, then it holds a line just fine.

I don't believe maxpesce saying that "most the first gens are moving into GT-3 where they can build full tube chassis, run perif port motors, and upgrade to better steering, brakes, and suspensions." If you build a tube frame chassis, then you are no longer 1st gen or 2nd gen except only by the outward appearance of the bodywork. With a tube frame GT car, you no longer have Mazda suspension. With GT cars, the only thing left on them made by Mazda is the castings of the motor housings. GT cars have to carry a weight penalty for IRS too; most of the fast ones run solid rear axles.

Bern

The best choice is what you can drive fast... there is NO favorite or preferred RX at the moment, in SCCA E-Prod

Race Times from this years Run-Offs and comments

Bob Neal (13B 1st gen) - 1:36.454
(could've gone faster - had podium finish in site, potential winner)

Tom Thrash (12A 1st gen) - 1:35.136
(could've WON, but got in a little tussle with Dave Lemon)

Jeff Dernehl (13B 1st gen) - 1:36.092
(qualified faster than this, and could've challenged for podium, had a race incident)

Tony Rivera (13B 2nd gen) - 1:35.826
(great driver)

John Wiesberg (13B 2nd gen) - 1:37.313
(another great driver... car was having minor issues all weekend)

Dave Lemon (13B 2nd gen convert) - 1:35.760
(Great car and driver... also had a chance to challenge for the win)

Jesse Prather (12A 1st gen) - 1:36.338
(Another fast driver with a chance for a podium)

Wayne Graham (13B 2nd gen) - 1:36:7663
(qualified faster...limited experience, first year run-off driver, but easily a top 5 car)

Aaron Downey (12A RX-3) - 1:37:674
(even Old School can run fast in E-Prod... excellent driver)

These were the top RX guys at the run-offs... as far as performance, not finishing order.

-Bern

Barwick

I would love to see the SCCA allow a rack & pinion conversion for the 1st gen, for safety reasons in IT and E-Prod.

Bern

Why for SAFETY reasons?!?! I've never heard anything about there being any safety issues with the 1st gen steeing box in racing. Sure it has crappy feel and it wonders a bit when worn... but there, at least to my knowledge, has never been a failure that caused any harm or anything.... do you have any info on this this?

-Bern

christaylor

Judging by the metric tons of stock 1st gens running in Spec and IT classes without fail, I doubt they're going to change any rules for "safety" -- that is until the chassis start breaking in half because Japanese steel decomposes after 30 years.

The above is a joke, in case you couldn't figure it out...

Barwick

In my opinion it's not safe to have a vehicle that wanders back and forth when going in a straight line. Not to mention if the driver has to make corrections in a turn, he has to move the wheel a (seemingly random) distance before it catches the other side, and then countersteer, then move back to the other way... it's a ridiculously bad situation for racing.

christaylor

Except for the fact that the steering doesn't wander in the turns. If it does, replace the steering box. I've found the power steering setup with no boost is the best overall steering, except for when the pitman arm bolt breaks off during an offcourse excursion, and when the LCA bolt loosens up and wallows out the hole.

DriveFast7

iTrader: (1)

I replaced my stock steering box with a junkyard one with new thick 90wt oil and it doesn't wonder steer. Stock boxes can be rebuilt for about $200. Allowing recirculating ball cars to upgrade to rack and pinion would be deemed 'rules creep' and not allowed.

Biggest saftey issue with 1st gens in EP is the front one piece hub and rotor separating and becoming two pieces while your wheel flys off into la la land.

Barwick

I saw that on an SCCA board, that was crazy, I was thinking "but the rotor is just the rotor..." then I remembered it's one piece.

THAT they should have to allow them to change to something else stronger & aftermarket.

Elevation7

I know a guy who has an E-Prod. It is by no means a streetable car. A full-out race car. But it kicks serious ***. Darren's a good driver, but his car is nice.

He has a 10,000 racing transmission. When he bought it, it had a dry-sump set-up as well. Sweet car. On a road race course, nothing can touch it.

It has like 210hp and weighs about 1800 pounds. With driver around 2000. Nothing can touch him, I mean nothing.

Bern

except other kick-*** E-Prod cars!!

If it's a true SCCA E-Prod, then he's a little underweight and probably adds a little weight to race legally in the SCCA.

-Bern

Bern

There is a huge debate on the rules for this specific issue, but at the run-offs, they let them run the alternate two piece aluminum hub and steel rotor set-up, for safety sake, until they study the whole deal properly.

It really seems that the manufacturing quality of the rotor that is installed is playing a big part in this deal. The cheap China, Taiwan, etc... OEM replacements rotor/hubs seem to be the parts failing, but higher quality pieces like the Brembo and OEM Mazda sourced pieces are not.... but I understand that you can't get the Mazda parts anymore.

The problem with just allowing all of the 1st gen guys to switch, is a competitive advantage gained by the lighter (at least 3lbs a corner), undoubtly stronger, aftermarket pieces. I'm sure the controversy will continue on this deal for a bit.


-Bern

Bern

But the wondering, as others have pointed out, is on worn or unproperly adjusted steering boxes... so it's more of a maintanence issue, then a safety deal. Like DriveFast7 points out, a properly set-up box does not wonder or cause an unsafe condition. I will agree that the recirculating ball set-up is not the best or even preferable set-up for racing, but this does not make it a safety hazard.

-Bern

SPiN Racing

I can lay it out for you in my vision....

1st gen EP...

12A rotor housings I gather are going to go away. SCCA REQUIRES that you must use factory housings.

13B 6-port GSL-SE... Yes better brakes bigger engine.. WOOT!... OK first problem.. Finding a GSL-SE you are gonna totally gut. 2nd problem.. you either have to put a carb on it.. or you need to FI it. You MUST RETAIN the stock throttle body, un modified, and the original intake manifold.. I gather port matching only 1 inch.

Then there is the brakes issue.. non-factory rotors issue. blech.

Course.. you have the very solid suspension, and the 4-link with a watts or panhard depending on your train of thought.
No IRS
Parts are cheap (If you can find them.. 1st gens are SCARCE in central Florida now)

2nd Gen

Vert. LOOK AT THE FRAME/UNIBODY!!! Can you say STRENGTH? There is a TON of metal and DIFFERENT bracing etc under the car down LOW. The chassis is TOTALLY different underneath. Yes there is a ton of stuff that crosses over.. but seriously look under one.
Strip it.. and add a cage.. it will be LIGHT. and possibly stiffer than a coupe.. with most of the weight down low.

Coupe
Get an SE? Hard top.. no sunroof to weld up.. light.. base model.. not as much to strip off. But.. wrong motor... low compression.
Get a 89+... much better.. you get the better intake and rotors.. plus the better aerodynamics on the frontend. Worse LSD.

Now... reality check.
You will put on some non-original parts.

Fiberglass:
Front Fenders
Rear Fenders
Hood
Hatch Frame

Lexan:
Front and rear windows

Suspension
ALL new shocks and springs
All bushings

Fuel Cell
Race Seat
Harness
Gagues
Radiator
Exhaust
LSD
Clutch

Then there is the motor
You would want the 89 rotors.. if not renesis.. if you are brave.. and feel like exploring in uncharted territory. (Yes people have done it.. but it isnt for noobs)
THen Carby or FI??
Can you tune a Carb?
Can you find one?
Got an Intake?
Can you afford FI?
Can you TUNE FI?

Lets talk rear end gears....
ISC Racing will make you any set you want from 1st gen gears.. for your 2nd gen.
Gotta get a good LSD, or Shim a 86-88 one.



BASICALLY.... you need to replace a TON on both cars.
Me? I have a 86 Sport I stripped... cause I already have it.
I have a 88 based motor I started with cause I want a reliable motor for the first season. Not a front running possible grenade.
88 Rotors.. yep losing a couple points of compression.. See above.
YES I have done some serious cleanup of it.
Yes it is ported real healthy. (Within the rules)
Waiting to buy a clutch atm.. cause they are spensive. LOL (2 Disk Quartermaster Button..No Flywheel)

If you can Find a car for CHEAP. And you have a given motor to work with... start there.
If you have access to a GSL-SE.. and can get it for dirt cheap.. go that route.

Most people I know of usually start racing with what they already have.. unless they are made of money, and can afford to buy X car.. and spend X, Y, Z, to have Joe Blow Racing prep it for them.

Barwick

I had it wander on my race car with a "wow this is really tight" (as tested by several IT7 racers) steering box.

Barwick

Thanks Scott.. THAT'S the information I was looking for.

cpa7man

iTrader: (2)

Barwick I believe your weights are wrong in your initial post. EP 1st gen is 2050 with 12a, 13b is +140 pounds. I'd have to look at the fastrack again but I'm pretty sure.

This is a quote from Dave Lemon (Maxdatrix) in response to my post on the scca production board(I've been trying to decide between 12a & 13b:
"We saw peak 12A power in the low 9's.
13B 84-85 style was dropping off by 9.5

My 86+ engine I shift at 10k+ -- and have the "normal" shorter life, hard on bearings, cracking gears, etc. problems.

As others have mentioned, dyno numbers vary a LOT. I went from "manual" data (look and write while holding at 10k !!!) to computerized, using the same water brake dyno unit, (both calibrated frequently) and the new set-up reads 10-15hp less than the old. -- And you can make impressive numbers by giving false inputs. I did a really impressive (and VERY not-real) run that showed, and graphed, an easy 385 !!! -- also have one with massive detonation that prints 13,185 hp!!! (and negative 12,000 on the same pull).

Tom Thrash showed that a well built, and well driven 12A can be as fast, and faster, than a 13B. He pulled out of the corners better then I did, but I had top speed on him -- came out pretty equal??

The current hp/weight ratios for all the E/p RX7's seem to come out about the same?? Having been on both sides of the equation many times over the years, I prefer more hp with the extra weight. It's easiest to pass on the straights with the extra power, and very hard for the more "nimble" cars to get around you in the corners. "

Even Dave says a 12a can be faster than a 13b, than again more power is a good thing.

Scott from what I'm told 12a parts are still less expensive that 13b parts. You MUST run the rotor housings and end plates from the GSL-SE in the 1st gen. These are very expensive. Now running the 2nd gen like your are gives you a lot more choices. That said I found a complete SE in FT Worth for cheap....... Hope to see some of you guys at the runoffs next year.

Paul

edit: Scott I think the brake issue has been fixed. Soon we should see official confirmatuion that we can run Sevensonly front brake setup(with stock caliper) or the KC Raceware one. (I've got GSL brakes upfront now)

cpa7man

iTrader: (2)

Chris, Please stop promoting the Miata's, I swear there mulitplying like rabbits. I hate them damm things.