david88mc

I went to a NASA event this weekend and was checking out the Formula Mazda's. Does anyone know what they have done to achieve 184 HP out of their 13B NA engines? I know the engines are sealed so you can't mess with them. They have carbs instead of FI. (I guess for tune-ability?) From what I have seen they want over $8000 for one of these motors new or you can get a rebuilt one for over $4000. Just curious why they would be sooooo expensive??????

Nihilanthic

The right exhaust/intake and tuning on stock ports has seen nearly 200 whp, supposedly.

184 (flywheel?) would be like falling off a log. Its a matter of proper tuning.

Liquid Anarchy

iTrader: (2)

They're Renesis crate engines, from what I understand.

jgrewe

iTrader: (1)

If it's the old style, not the new 'pro' car with the renesis, they are stock port engines. They are assembled and tested to be equal but some end up a little more 'equal' than others... It's all in the tuning and a pretty good intake manifold and exhaust design. A good friend of mine won the pro series back in '00 or '01 I forget which year. He said it was all carb jetting and shock testing to make the car work. It's a low volume of rebuild and testing the engines for the series that's why its so expensive.

david88mc

The new(est) series (PRO Formula Mazda) have the Renesis engine in them that is rated at 240 HP. I think the older guys are allowed to replace the 13B with the Renesis engine but incur a weight penalty for stepping up the HP.

david88mc

I figured the exhaust and intake had a lot to do with the jump. I still don't understand the deal with carbs instead of FI. I guess they wanted more tune-ability and they could probably monitor them much easier. I would just think the FI would be easier and more reliable. Of course, I don't know how to tune carbs either.

jgrewe

iTrader: (1)

Carb=cheaper to build/sell. EFI is more tunable.

Black91n/a

They're also rev limited to about 6500rpm or so IIRC. is to keep them reliable on track. I also beleive they're 4 port 13B's, o it's either an old block, or a turbo block. This There's guys out there winning with motors that are well over 5 years old. That's pretty good for formula car racing. As for carbs, the SCCA has traditionally been "scared" of EFI, they know carbs and can regulate them more easily.

RX-Heven

iTrader: (1)

The older Star Mazda cars are the earlier series port 13b n/a's with stock internals that run with Weber carbs and Racing Beat manifolds. I believe they may be able to run ceramic seals in the near future if they are cannot right now. They are not limited to 6500 rpm. Carbs are cheaper and easier, period. 184 is fwhp.
How do I know, I raced these things for a few years and helped maintain ~20 of these cars at a shop.

One of the major focuses when they designed these cars was to end up with an inexpensive setup that was easy and cheap to maintain/repair and was responsive to setup changes. They succeded imho.

The new Star Mazda cars have absolutely nothing in common with the older versions except they are rotary powered but with a Renesis instead. Carbon tubs, pushrod suspension, aero that really works, sequentail trannies, the list goes on and on. However, these things are not cheap like their older counterparts.

jgrewe

iTrader: (1)

Dave, did you ever run against Bernardo Martinez in the FM?

Black91n/a

I could have sworn they had a rev limiter at some rpm in the 6500-7500 range.

RX-Heven

iTrader: (1)

Nope. I believe he did FM a year or two before I was racing.
I did "race" with Scott Speed in these cars on several occasions. I say "race" beacause I never saw him after the first turn , and I'm no slouch. I guess that is why he is now in F1 with Red Bull (Toro Rosso) and I'm not

christaylor

The expense on the motors is because you have to get them through Star Cars. Buying the motor direct from Mazda would be closer to $2k, but you're paying for equality and the seal.

The class is not a bad deal for a full-prep racecar. Used units with a boatload of spares are $20k, and just about anybody can work on them. Plus, the chassis are basically old Formula Fords, which means they're indestructable. The new cars, though, not so much...

Those dudes were hauling *** at MSRH this past weekend!

david88mc

Yes they were Chris!!! The guy in the black one with flames is fast while having his rear end all over the place!!! Were you in a spec RX7??? You weren't in the car that had the off course excursion were you?

Man that guy looked like he never slowed down and went spinning right through the fence!!!

turbosa22c

im not sure but i think the rules restrict fuel injection.

christaylor

I was just spectating on Saturday, but heard about Jeff's shunt on Sunday. Video from his car is on the Texas SRX7 site (which I run) -- www.txspec7.org

Next time you come to a race, let me know, and if my car is there I'd be happy to have you climb all over it. Not as cool as a Formula Mazda, unless you spot some of our tricks.

boostedHULK

iTrader: (1)

carbs atomize fuel better than fuel injectors, they make more power on say the same motor less the fuel injection. A lot of the NA sport compact drag guys use them for the same reason.

jgrewe

iTrader: (1)

The carb/EFI thing is a whole other can of worms. How come EFI usually comes with a weight penalty? Its because it will make more power over a greater rpm range only because of the tuning that can be done. A lot of times a carb will equal the EFI at the very top end but it depends on the venturis its breathing through, it can make more. At the bottom end of the RPM range injection will be tons better than a carb if that carb has big enough chokes to make more power than the injected engine up top.

david88mc

Hey Chris, I'll try and stop by and see you guys at the next event I attend. I usually work to make a few $$$ for my soon to be "race" car. That event was crazy time wise. The way they set it up we didn't have any down time. We didn't even have time for lunch Saturday!!!