adamBOM

Hello members of RX7club!

I'm a new member (obviously). And the reason i joined is for some info on 13Bs and FCs in general. I'm looking into getting an FC for an autox racer, maybe even full road course. N/A is fine with me, i don't wanna gut and ruin an example of the TIIs. A good friend of mine in highschool had an FC TII and i loved the car, always had a love for rotaries. Well, now i have the chance to build one. A couple questions to the wise:

1. Rotaries are great motors indeed, but are there any common issues with 13Bs that i should know about other than apex seals?
2. I plan to rebuild the motor with Racing Beats rebuild kit wich includes all gaskets and a set of carbon apex seals/springs. Is this a difficult task? I'm a technician but i work on BMWs and Euro cars specifically, so i'm not familiar with rebuilding a rotary. I have tools/equipment at my disposal.
3. Any issues with the manual transmissions in these cars? Syncros, bushings, seals, anything out of the ordinary?
4. Is this a decent chassis for handling? I know the balance is great with these cars, but is it capable of holding the curves with the best of em?


Thank you all, for your input

trochoid

iTrader: (6)

Spend copious amonts of time reading through the 2nd gen and 'Race Tech' sections.

1. Maintinance and never overheating the engine are of primary importance. When racing, a add bit of pre-mix in the fuel tank, good for daily driving too

2. If you're a line mechanic, rebuilding a rotary shouldn't present too many problems. Skip the carbon seals, stock oem apex seals are the proven tried and true choice. Carbons reduce low rpm sealing/compression numbers and are designed for, 8.5k+ rpm engines. If the engine build is for racing only, carbons may meet your needs Download the FSMs from the provided link and buy a rebuild video. I have the Rotary Aviation one and I'm quite happy with it.

3. In regards to the tranny, 2nd gear synchros seem to wear out too soon in both the TII and NA trannys. Some have used a 1/2 and 1/2 mix of standard tranny fluid and ATF with good success

4. The best of who/whom? What type of racing/series/sanctioning body are you contemplating raceing under? There are a good deal of suspension mods and parts available for autocross, road course and drag racing. the 2nd gens tend to suffer from snap oversteer. Replacing the rubber DTSS bushings with the bronze ones helps that issue.

Welcome to the forum, here's a couple links to the online FSMs, .

http://www.wankel.net/~krwright/cars/rx7/manuals.html

http://foxed.ca/foxed/index.php?page=rx7manual

Welcome to the forum. Best suggestion I can give you is read, read, read.

I have a 2nd gen for my daily driver, the next link is the fun one. The widebody will literally run circles around the 2nd gen, wonder why?

https://www.rx7club.com/build-threads-293/unvieling-12a-bp-widebody-462184/

Kentetsu

I prefer 1st gens myself... You lose the independant rear end and r&p steering, but you also lose a lot of weight...



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Icemark

Apex seals are not really an issue, unless you have radically mis-tuned the car and are getting detonation/pre-ignition

I would recommend using Atkins kit instead. It will be considerably cheaper and pretty much all the same seals except for Atkins makes there own steel apex seals. Either Atkins or OEM two peice apex seals are going to more than fine for 99% of the applications out there.
On a non turbo, the M type tranny is near the top of its design limit, but a still can handle up to 200-220 hp just fine (more than you will probably make on a non turbo with out major work).

Big key on all Mazda transmissions however is not to use a GL-5 gear lube, but instead use a GL-4 like Redline's MT-90. GL-5 gear lubes because of the additional shock protection tend to scar and eat up the syncros (and any copper or bronze) in the transmission making shifting worse. Use a good quality GL-4 (preferably synthetic) gear lube for the best results and longevity.

Well a properly set up FC can handle better than most newer cars made today, but the ride will be harsher than many newer cars. Remember although the FC has that neat rear wheel "steering" (toe in position and toe out position are based on lateral and forward and rear ward G's) that typically does not work well for a drift type car, and it has a basic strut front suspension, the car works best on higher speed tracks or roads. It was designed for America's highways and mountain roads. So on a tighter autocross course, the extra weight and design can sometimes be a draw back until you understand the chassis and how to drive it to its limit.

adamBOM

Thanx for all the info guys!!!

This really helps with my decision to press on with finding an FC. I've contemplated a SA/FB, but i'd hate to use a carb 12A , and GSL-SEs command a higher price than FCs. I have far more experience with good 'ol FI, since i'm of a younger generation

I'll look into the atkins kit, and i'm glad to hear that OEM apex seals will do fine

dpf22

Take a trip on over to www.nopistons.com and take a look at their engine building/porting forums. Tons of good information at the fingertips, plenty of people willing to share. A well built 13b can make over 200rwhp with the right mods, but don't expect to make it with the stock computer. Oil cooling and proper lubrication are main focus areas and should not be left stock.
There is a lot of good and bad information out there, be ready to read for a couple of weeks at least before making any purchases. You want to be sure of what you are doing as a lot of internal parts are expensive. If you plan on racing, you should look into mazda motorsports and their discount. Call them up and talk to a rep and see if they will let you be a member in lieu of racing later on. They are pretty cool there so its possible.

As far as the FC Chassis goes, ya, the rear suspension is a little finicky. There are plenty of parts to buy that level it out. A good grasp of how the car handles makes a large difference in these cars. They are a very twitchy car and thusly have to be treated as such. Problem areas such as chassis stiffness in the rear (large door openings and the hatch area) will need to be addressed and adjusted for class. Good car for autox, but the rear likes to step out so I prefer to stagger the tires on the large side to give me more time to accelerate instead of sliding into/out of corners because I was too aggressive.
I am not the best driver, but I am within 2 seconds regularly of some of the best drivers in my region who drive lotus elise (111R) and a bmw 328i both equipped with ohlins suspension and a slew of other parts that make them dangerous. That was also while running my puny 225 wide slicks(they run 285's).
Anyways, I've probably said too much, but you get the point.

andresj

iTrader: (8)

my fc is carbed i love them