Posted by Chris V. on July 19, 2000 at 19:57:07:
Hello, all! I've been reading many of the threads posted here over the last...looks like 8 months, or so. Some serious debate over the merits of V8 installations in 2nd gen RX7s. And I'm not posting here to piss anyone off. Rather the opposite.
As some of you might know, I built one. I've gotten hundreds of e-mails from fellow RX7 owners who have also ended up with dead RX7s, and are tired of spending money on rebuilding the rotary, only to still have relatively low power levels for the money spent.
Don't get me wrong... I love the rotary engine. I've owned and built many rotaries over the years, from R100s through RX2s and RX3s. I've put rotaries in other cars (like an MG Midget. THAT'S a serious ball o' fun!) I love the sound of a ported N/A 12A at idle. I love the speed of a new TT 13B. But it's been a long time since you could rebuild a rotary for $300... and a 2nd gen needs more than 150-200hp to be rapid.
My 2nd gen was purchased at 113k miles, and seemed to be in perfect condition mechanically. Got 25-28 mpg. Ran smooth. Since I had been autocrossing (in nearly every kind of car) for nearly 15 years at that point, that was what I wanted to do woith th ecar. So I had a frined who is a multi-time national champion tune the suspension, and off I went. the car worked great, beating many more radical cars, and garnering me a first place trophy for the season (our club has over 20 national champions, some multiple winners, so even though I haven't had the time or money to go back to the nats, I do get a good feel for how I compare...).
At the end of the season, the car (which was also my daily driver) died. It had always had a problem with flooding (as many of the early 2nd gen cars do), though this time it may have run lean. At any rate, I went to start it (after having driven a couple hours away from home) and nothing. Turns out an apex seal on the rear rotor destroyed itself, taking out the rear aluminum housing, the rotor, and gouging the hell out of both the center and rear iron housings. Instant deceased 13B 6-port.
My choices at that point were rebuild that engine, or buy a used engine and rebuild *it* (after working with rotaries for years, and some of the better NW rotary tuners, I know that buying used rotaries is a tricky thing...). Bare minimum cost to me was going to be in the neigborhood of $2500, just to get it back to its stock 145hp self. Never mind trying to make power out of it. yes, I know full well that there are mega hp rotary engines. But when was the last time you saw a 400 hp, daily driveable, 25mpg, sub-$2000 one? Since the car was a $2500 car to start with, and a $500 car with no engine, I really couldn't justify the cost (which I didn't have, anyway). I liked the car, and it worked real good as a slalom racer. And I noticed how big the engine compartment was while the engine was out...
Now, I was raised with seeing some of the worlds best hybrids go road racing. The Cobras, the Cunninghams, Lister/Chevrolets, amongst others. Porsche powered VWs, Chevy powered road race Jags, Sunbeam Tigers, TVR Griffiths (you think 2nd gen RX7s are unique? Not like any of THOSE cars...). Taking an excellent chassis, and dropping in a strong engine is a tried and true route to not just drag race performance, but road race and autocross, too (anybody remember a couple years back, when the top 2 A Mod autocross cars were a rotary powered Sprite, and a 302 Ford powered Midget?). Just so happened that I had a 302 sitting in the garage already from an ex-patrol car. The Ford 302 weighs less than a hundred lbs more than the 13B (While this fact is well documented in engine swap literature, like those found in Kit Car guides, I actually took the two and weighed them. The 302 was 420lbs, and the 13B was 340) And it's physically not too much bigger. In fact, in the 7s engine bay, it looks like a V6. I didn't use that 302 (as it was my brother's, for his '63 Comet S22), but a good friend had recently built a 302 for his race car, and had decided to go with a big block, instead. So I purchased it from him at the cost of parts (basically, what it would've cost me to put it together. Except it was already done, so there was no waiting. Good thing, as the car was my driver, and I couldn't have it down for too long). That engine dynoed at a bit under 400hp. For a thousand dollars (which I made payments on at $200 a month...) I also picked up a modded AOD 4 sp automatic (I know what you are going to say, bet there are a ton of good reasons for using it, not the least of which was the fact that a couple years before, I had spent 6 months in a wheelchair because I had both legs heavily burned in a car fire (not my car, not my fault), and my left ankle hasn't been the same since. Add to the fact that it's easier to do teh conversion that way, and teh fact that most of the V8 powered autocross cars in my club (including a couple national champions) used automatics, in order to be able to concentrate on learning the courses faster, and smoothing out the V8 power application).
The engine went in like it was supposed to be there. The chassis already had the autocross mods done to it. I merely moved the battery to the well behind the passenger seat). Since the engine sat nearly completely behind the front axle centerline, the added weight (which, as I explained, wasn't much) got spread fairly evenly front to rear, with more actually going rearward than frontward (giving it a better f/r weight balance than it had stock, as measured on the Fordahl Motorsports corner scales used to set up nationals winning autocross and road race cars). the stock 4.11 IRS has held up to the added power for nearly 6 years (4 while I had it, and the current owner added a 125hp nitrous shot to it...yikes! Unfortunately, he also added a fugly hood scoop to cover the taller air cleaner installation...but it's his toy now).
The conversion cost me less than $1500 to do (I designed and built all mounts myself) to start with, though I added some extras as time went by (the Griffin radiator was one. Turned out that the 113k mile stocker was plugged, and would've cuased the downfall of the rotary pretty soon anyway...) I ended up with a unique car that I built myself. One that was very quick, handled vastly better than stock, and cost less than just the 225 hp Cartech turbo kit. Now, I really don't advocate doing this to something rare and valuable. The 2nd gen N/A RX7 is neither. It is, however, a great chassis to build from, regardless of which route you decide (or have the budget) to go. I'm not here to tell anyone that they should convert their cars. That's a personal decision that was best for me at the time, not necessarily the best solution overall, for anyone else. I'm merely defending and explaining the choice to do so. And I probably wouldn't simply buy one to convert (unless I found a sub-$1000, dead convertible...lol!).
Oh, BTW, the final year that I had it (2 years ago) I ran it against the RX7 that got 3rd in class (E mod) at the SCCA nationals. That car weighs 1500lbs, has no interior, is trailered, and was running on 12" wide slicks. Compared to my fully licensed and street equipped 2700lb driver with 225/50 15 A032Rs. I was less than 2 seconds off that car's pace, and the fastest street car by a good margin. In fact, judging by my car's continual results, I could've placed 4th at the Nats in E-mod that year. With a street car. No, it wasn't a nose heavy pig that handled like crap. No, it wasn't ruined. And yes, I miss it. you guys that are building up V8 conversions (and some of you who have e-mailed me over the years) enjoy your cars! That's what they're for. And to those of you who are building sweet rotary cars, enjoy them, too! But please, both sides: no moronic bitching about the "other guy's" choices.
