I am planning on swapping a firebird 3.8 v6 and associated trans I to my 87 Mazda rx7.
Any hints tips or tricks to get this engine and trans to live at the racetrack all day
Any specific items to worry about with this drivetrains?
Any tips or tricks to easily and cheaply make some more powers?
Thanks!
Rob R.
Don't know much about the swap but check out norotors. I think there is some info on that swap there.
Double 007 is/was running chumpcar with that setup. Wasn't quite as fast in a straight line as our 302 1st gen but I think quicker overall.
Does the Firebird 3.8 have the same awful lower intake gaskets as the FWD 3800 S2? Definitely replace with felpro metal frame gaskets if that's the case.
In reply to Kenny_McCormic:
Wikipedia tells me (so grain of salt here) that the 4th gen F-body 3.8 was the L36 version of the engine in question. There's a number of potential issues with these, like the intake gaskets, and the plastic upper intake manifold that likes to burn out around the EGR passage, and the head gaskets that let go more often than they probably should on an iron head / iron block engine.
If it can be kept within budget (I assume this is being done for Chump or LeMons?) then it makes sense to have this awful sounding engine out on the track. Read good things on TTAC.com about an FC/3.8 race car offering lots of reliability and relative fuel economy.
I'm pretty sure the F body got a different, less troubled, possibly metal UIM, the FWD one would put the air hose about where the radio goes in a Camaro. But definitely do the lower intake gasket (get the most expensive felpro kit), and upgrade the "heater elbows" on the LIM to aluminum if applicable (might also be FWD only).
Also run a PF52 (steel center, no plastic cores!) oil filter (or equivalent) if it will fit in place of the PF47, the 52 is bigger, double check those numbers as they are from memory.
I'd stick with a turbocharged rotary if I wanted to race it. Boingers don't like living at sustained high rpm. 
Turbo rotaries tend not to like sustained high Rpms for 24 hours either. Ask me how I know....
That and the HP would be less and the fuel consumption higher and generally more expensive.
We raced one for a while. It was okay but not worth the hassle.
I assume this is a case of you already have the firebird? If you are set on v6 swap in and don't have tge motor yet I think the 4.3 may be the better option. I really like the idea of a v6 in an fc. I wanted to try one of the Mazda V6 motors in one but transmission choices got weird.
The 4.3 is very similar to a SBC. I do not want another SBC. Those motors do not like crapcan endurance racing. I had 1 motor last 6 races and several engines not last a race.
Also, I think the power is similar.
I would appreciate it if you could convince me otherwise!
I do not have the firebird ...yet.
I'd have to agree on the 3.8 vs the 4.3. The 007 team lost their initial motor(4.3) early in their initial race.
Oddly enough on the SBC comment, while it seems to hold true the team I'm now running with has had great luck with the 97 SBC in the Lincoln.
Yep, if you find a good one they seem to last. The engine that went several races cracked the block due to my stupidity. It froze.
Rob, I'm out of town at the moment, but when I get home remind me to get you hooked up with our team owners. One of our cars...well, actually it's "the boat"...has run the 4.3 since its' birth. The original motor that came with the truck lasted 11 or 12 races. After it went kaboom, it has since gone through 2 motors in 3 races. However, the first of the replacements blew up because the throttle cable snapped while I was driving it and the engine hung wide open for a second or two. The last one was crap when the junkyard gave it to us, so chalk it up to a bad purchase (we got our money back). Overall, the 4.3 has been good to us. It doesn't like to rev, we shift at 4500rpm, but if you keep it oiled and keep it cooled, it's decent. Lots of torque.
One of our other cars, the TR7, runs the SC 3.8. They've gone through half a dozen motors. I'll let the team owner give you all the details, but I think a lot of it has been cooling issues, they've fried a lot of the motors. That said, they finally have the drivetrain issues sorted out and the car is incredibly fast. As in running in the top 10 overall fast. The keep having non-powertrain related issues that keep them from a great finish, but the car is fast!!
I am quite familiar with your team. Do you guys still run the civic wagon thing too?
Three pedal mafia.... You guys are nuts
Our Civic wagon succumbed to rust enough in the suspension pickup points that I didn't trust it anymore, but we put most of the good bits into a civic hatchback, including the motor that now has about 18k race miles on it, plus being in my moms daily driver for 9 years and in a junkyard before that. For the boat, we are done with 4.3s, looking to 4.8 or 5.3 V8 when it comes back. Biggest thing we learned with SC 3.8s is make sure to have enough clearance between the oil pan and pickup, that's why we blew 2 motors as it was starving for oil at high rpm as it was too close.
Im tempted to say you should go for a cheap v8 if you can find one. Then just granny it around the track and still be quick.
I don't know all the ins and outs of a 3.8, but wouldn't a mildly ported rotary make similar power and you'd then be an extra 75 points ahead?
A ported rotary isn't going to make 200hp and 230 torque.
That would be quite an aggressive port. Also, I am fairly certain that fuel consumption would be pretty aggressive.
I have no need to save my points. At this point I am below budget anyway.
I have always wondered if the 3L V6 motors from the Acura's were any good. I actually could get one complete with the transmission, harness and everything from an MDX for peanuts (like free). I done know how much it would take to mount it as these are transverse mounted things but they have lots of power and seem to be reliable street motors. My fear is that they would not survive due to oiling issues. They would probably require at a minimum an accusump and maybe more.
I was under the impression that Honda engine is the one used in the miata swaps.
wvumtnbkr wrote: A ported rotary isn't going to make 200hp and 230 torque. That would be quite an aggressive port. Also, I am fairly certain that fuel consumption would be pretty aggressive. I have no need to save my points. At this point I am below budget anyway.
There's no question it won't make 230ftlbs, but 200hp at the flywheel is certainly doable. This is a S5 making 185RWHP: http://www.rx7club.com/time-slips-dyno-128/who-has-highest-horsepower-na-6-port-1028032/#post11396222
This one making claims 199rwhp S5 stock ports (hard to understand, but source is very reputable): http://www.rx7club.com/time-slips-dyno-128/who-has-highest-horsepower-na-6-port-1028032/#post11400712
Semi-ignorant formula: You can gain ~15-20% with header/intake/exhaust and basically gain back the flywheel-rw loss (50 points), call it 10hp with a ECU/tune (75 points) and gain whatever a given port job is worth. Throw on some RSR Race springs, KYB bump stops and some bilstein HDs and I have to believe you have a pretty competitive car. This is my preferred bench racing setup, but my luck with rotaries just isn't there. (Hence I went the opposite direction and have miata)
What is your typical fuel economy?
I already have the engine tuned about as far as it can go. We are making 146 at the wheels right now.
Stock ports stock intake manifold, good headers, exhaust, intake piping etc...
We do have a competitive car now. We win and or finish in the top ten just about every race we enter.
I am looking for more power at this point. Our car handles quite well.
If somebody could tell me how to legally make 180 to 200hp na with a rotary, I am all ears.
Our car has no emissions, no power steering or ac. It has a decent header, no cat, and a borla stainless catback.
I have used fuel pressure and "filters" on the map sensor to run around 13:1 AFR.
I am stuck with the stock s4 intake. I am stuck with the s4 engine management.
Typical fuel usage is 6.5 to 7 gph.
146rwhp is ~170hp. Your fuel economy sounds respectable. The stock system can handle a street port, I see no reason why it is not legal and worth 0 points. Other than the header, where have you spent points?
On the 4.3 is it oiling or cooling that are the issues? I don't have experience with them for use in racing but I have always wanted to build one that was moderately warmed over and see hat it could do.
In reply to Snrub:
As I understand it, a street port is going to add only a few horsepower. I would need to spend several hundred dollars to do it (basically an engine rebuild).
If I could streetport it and not change anything else and gain 20 hp, I would do it. I don't think this is likely.
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