Mazda RX-7 V8 Conversion

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If anyone could help me out, I cannot find a good quality site that shows the parts needed for an RX7 V8 Conversion. My friend is considering this instead of turboing so please if anyone could link me to some sites that explain or at least list the parts necessary for this conversion it would be very helpful.

posted by  Pythias

Good luck fabricating everything you need. Might as well go 20b.

posted by  importluva

No not 20B , Chris has talked about this 1 enough already, just do urself a favor and go V8

posted by  Walt

oh just while you two are talking rotaries, what do the 13b and 20b stand for? ive searched but just cant find anything on the subject. so can someone help?

posted by  ahoo

Would love to help you out...

Three excellent sites to work with, V8 is the only way to go with the RX7 if you want cheap, reliable power. Grannys is great!

As to importluva who said why not do the 20b conversion, well, my girlfriend went that way with her 94 Touring RX7...went through the near stock 13b-rew as soon as she bought it with what I think a little over 60k or 80k miles (apex seals WERE 3mm, still didnt hold...had other problems as well). So we looked into our options, and at the time I found out a page that sold stock and race prepped rotaries ( and they had a nice ported 20b (claimed 340-360 stock horsepower) for $4200 inculding tranny and complete engine w/ ECU and everything...then the problem arose of...where to get this thing put in. After many calls to many places, no shop within hundreds of miles of Atlanta would lend a helping hand, no place had ever done it. So we had to turn to more resources to find independent guys, and finally got willing people, only problem was, they knew it's impossible to find people to put this engine in anything so they knew what to charge. I got quotes anywhere from $2500-$4000 to fully mount the engine/tranny and to get it up and running. Most everyone said it's a tedious process and would take them a few weeks to finish off. Finally we got a guy who said he would do it for (I think it was) $1700...only problem was it took him a month to finish the deal. But things went seamlessly, and the new enigne/tranny have probably 10k miles on them now with zero problems, although with rotaries problems are always in the future. After going through the entire ordeal my girlfriend and myself both agreed, an LS1 would of been a much cheaper, easier and powerful option to go with. The best thing the RX-7 chassis is great for even all the torque V8's put out. I remember a friend and I put a Ford 302 into a FC 2nd gen RX7 and it took the two of us TWO days to take the old and put in the new. Final cost tally for that swap was well under $1500. The old 1/4 mile was 15.80s and the new 1/4 mile with a stock 1988 302 from the junkyard with exhaust, new heads and intake manifold/intake was 13.60s.

posted by  thunderbird1100

13b and 20b were engines. The 13b started out life in the FC 2nd gen RX-7 and lived all the way through the FD 3rd gen RX-7 (it was a two rotar, rotary). The 20b we never got stateside but was in the Cosmos in Japan (three rotar, rotary).

posted by  thunderbird1100

Thank you this helps greatly. I googled and yahooed and couldn't find it lol, this will also be a work in progress as of he is planning for the future and if he decides to do it (which I believe he will) it will happen around next summer. But I also advised him to go with a 302 rather than a 350.

posted by  Pythias

Wow. Got to this one late. Granny's uses my car pictures to advertise their Ford conversion, but my car didnt USE their conversion and they didnt use my parts. te plans to make teh mounts for my conversion are still on the site, however, as well as a small writeup on the build for my car. their forum has all teh knowledgeable people on doing the conversion.

They even are organizing a V8 RX7 meet for next spring. So far, nearly a hundred owners are signed up!

While I won't tell someone that they should do a conversion like this, I will help them once they've made teh decision. And I will tell of the reasons that it's better than, say, a 20B conversion. mainly, the 20B is more expensive by a long shot, ins't as reliable, requires at least as much work, and does the one thing to the car that the rotary purists claim the V8 conversion does: ruins the f/r weight balance. The V8 conversion often improves the balance... (for example, my car had less weight on the nose than a stock RX7 TII, even though I did nothing to lighten the car).

the engine choices for a swap, in order of desireability, are:

Ford 302
Chevy 350 (old style)

The LSx series and the Ford 302 are the lightest, but are on opposite ends of teh cost spectrum, with the LS being much more expensive than the 302. But it's easier to make a lot of power from the Chevy (a couple minor tweaks on an LS1 and you can have almost 400 hp at the rear wheels).

posted by  ChrisV

Thanks ChrisV, my friend said he will be getting job soon and saving up to do this. I will definitely bookmark the page for when the time comes, assuming all goes as planned.

posted by  Pythias

When installing the 302 in my friend's RX-7 he was telling me the Ford motor is easier to work on than the Chevy LT1/LS1 motor, is this true? I wouldn't know as I never have touched both motors really.

posted by  thunderbird1100

So heres the thing, I always knew our good friend Chris here was a damn Genius, so I googled his name (Which Im not gonna release, but found on a certain website that had to do w/ alternative engines in certain models of cars) and came up with an impressive list.

Tons of engineering, tons of cars, tons of experimental engineering and areonautical stuff.

Anyway, the point is, big ups to ChrisV! :thumbs:

posted by  Zalight

20b or V8, its a tedious process in any rx7 and the rx8. 20b is rare in the US, more unique and thats why i suggest it.

posted by  importluva

It's definitely cool, but it's vastly more expensive, and it does negatively affect the weight balance, unlike the V8 conversions.

But is is way cool! One of the guys here at work has a 20B FC convert. Very fast.

posted by  ChrisV

The 302 is a bit easier to work on, due to the front mounted distributor. And it's physically smaller so it's easier to reach everything. But the actual difference is probably very minor. These aren't extremely complex engines. Just the electronics are complex, and those are no more so than any other car.

posted by  ChrisV

20b is a lot more expensive and tedious, first hand learned of that. But like Chris said, they are very girlfriend's 94 Touring has suprised a few 03-04 Cobra drivers.

posted by  thunderbird1100

Go to granny's. 13b is a 1.3l twin rotor and 20b in2.0l quad rotor

1nasty5point0   29 Nov 2012 02:03

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