V8 Rx-7 F.A.Q.
 

I've added a FAQ to my site for V8 (or other swaps) converted RX-7s. It's still young, but hopefully as time goes on it will grow and become more refined.

http://www.team140.com/faq

Sticky!

yes, another sticky vote.

was checking out the swap details for the first time tonight, and ran accross this on tc, faq's been a great place to start.

Stickied

You should have a "Last Revised" date somewhere on the main page.

Good idea. I'll add that on the next update.

awesome post thanks bro

For your faq, you might want to paraphrase much of what's in this site:

http://www.britishv8.org/swaps/index.htm

Especially this slightly tongue in cheek page, entitled "TOP 10 REASONS TO BASTARDIZE A PERFECTLY GOOD CAR":

http://www.britishv8.org/swaps/top10.htm

Links are dead.

Yeah, looks like they recently revamped the entire website. It had links ot a LOT of big engine/small car conversions, as well as Why to Bastardize a Perfectly Good Car FAQ.

Ok, teh new versions of the links are here:

http://www.britishv8.org/Articles/top10.htm

And the links to all the cars are located here:

http://www.britishv8.org/British-V8-Website-SiteMap.htm

Something to discuss "weight balance" Gen 1,2,3

The rotary engine, support equipment, and exhaust systems are heavier than they look. Typical weight gain for a 1st gen V8 conversion car is only 75-125 lbs.

One of the main engineering goals of the RX-7 was to stay close to the perfect 50/50 chassis balance. When they added the extra weight of a turbo system to the Turbo II model(180-200lbs), they needed to come up with a way to maintain the chassis weight balance as much as possible. Some of the methods they used include...

...They went to an Aluminum hood
...They moved the intercooler rearward to the top of the engine
...They used a heavier spare tire & jack

This just goes to show that the Mazda factory uses the same methods to balance their cars as the regular guy. They reduce the front weight as much as possible, then move components if possible, and finally add weight to the rear if needed, in that order.
This is the biggest reason the added 180-200lbs of the Turbo II option did not ruin the balance and handling of the RX-7. The factory decided that the extra power that the turbo system offered more than offset the added weight.
This is what power-to-weight ratios are all about.

Some weight related numbers...

...An aluminum intake manifold is 28lbs lighter than cast iron.
...Aluminum heads save about 50lbs over iron.
...An aluminum block will lose ya another 55 to 95lbs.
...A 4.3 V-6 is only 11 percent lighter than a V-8.
...An aluminum hood(turbo II)will save you about 30lbs.
...Headers are 20 some lbs lighter than iron manifolds and headpipes.
...The typical RX-7 A/C system weighs 55 lbs.

...The RX-7's layout and structure is well suited to engine conversions. The rotary engine's eccentric shaft centerline is way up in the center of the rotary engine, dictating a much higher transmission location than that of a piston engine. The net result is that Mazda designed the RX-7 with a HUGE transmission tunnel, big enough to fit even the monster T-56 6 spd manual transmission which was used in the Viper and Corvette. The rotary engine's low torque output required Mazda to use a very heavy flywheel and a high rear gear ratio, a combination of factors that combined induce large amounts of stress on the RX-7's rear axles and hubs. Mazda planned accordingly, and designed plenty of strength into the RX-7's rear differential/axles/and hubs. Experience has shown that the stock NA RX-7 components are strong enough to withstand low 10sec 1/4mi passes, a feat that requires around 500hp.

The RX-7 chassis is well suited to V-8 power. It was designed as Mazda's flagship sports car right from the beginning, with many features that address the dreaded chassis flex that plagues other small car V-8 conversion candidates. RX-7 design features include...
1...a very large transmission tunnel. The large tunnel dimensions necessary to accomodate the rotary engine's higher transmission location add considerably to the beam and torsional strength of the RX-7's floor pan. The 3rd gen cars use struts across the bottom of the tunnel to further enhance this effect.
2...deep door sills add even more beam strength.
3...generously rounded door openings add body structure torsional strength.
4...subframe connectors are installed right from the factory. As countless highly abused RX-7's can attest, there is none of the buckled quarter panels or popped out windshields the are common with other V-8 converted small cars that were originally designed with economy in mind.

Yeah we all can read that on grannysspeedshop.com but as we all know their are purists that like the sohc 4 banger in the datsun 510's and those that put sr's or 13b's in them. Some like the 4age in the corolla other prefer the sr or 13b. I mean as adults and car fans we all have different tastes and opinions we will swear by. In my opinion the 7 heads that won't accept a v8 rx7 as a 7 anymore is because 75% of the v8 guys blew up the rotary and blamed it on the engine instead of the fact they ran 14PSI with stock fuel system or didn't upgrade the ignition. I mean we know the 13b costs but all import parts cost a buttload of money to mod so to me the $$$ thing don't count and v8's aren't neccesarily more reliable when modded their just cheaper and you can accidentally find a manual or some guys that know how to rebuild them just cuz it's been here since like 69.
Personnally for those that have,had or are getting a v8 they ain't care free, but it's the fact you can't go to a junkyard and not find a 350 for $500 bucks they are like cockroaches man their everywhere. Which is great and since they've been here you can mod a 350 to get 450hp all motor and it last for a good period I mean it'll at least get 100,000 if maintained properly. But hopefully the guy with the 500hp v8 that lasted 300,000 or the 250,000 13b stuff won't end up on here.
For Example my best friend has a 63 mg cobra witha 289, lasted 28,000 mile of full throttle funa dnwas fully built andf maintained like ashowcar. I mean that enough to make me won't to get a chevy but my buddy mike said it happens and shrugged it off. While my uncle swears by ford and tells me truthfully a modded 31 or 350 will get 180,000 at most but he won't let itr get that high. He says true gearheads prevent it by a rebuild so it's still in good condition(90,000) cuz if you run it till it blows your facing extra cash for maching for no point. He also tells me driving a rx7 is like driving a gas tank wit a match in it cuz he knows about the fuel pulsation dampener flaw.
Take it for what it is and nobody take this as a diss but I hope you can understand what I'm saying and tell me you thougths fellas.

im looking into a v8 swap cause im looking for the most bang for the buck. i have alot of friends that race dirt track and they have all kinds of extra parts laying around.

Does anyone here know the actual price difference between the LS1 and LS2?

the link is dead :(

Probably 2-3k depending on what you are actually getting... I'll have less than 2k in my LT-1 / T-56 combo, and that is including the engine rebuild... I couldn't find a LS1 / t-56 combo by doubling that amount...

im having an issue finding a ls1 also :(

I guess it's all about being patient and keeping your eyes out at salvage/junk yards. I was looking at the LT-1 as well. The only noticeable diff is that it pulls rather than pushes like an LS-1, right? Also heard of better trans on LT-1/t-56.

:scratch:

They are all over the place....


check out cleveland pick-a-part or v8rx7forum.com

as far as ls1 or ls2? go LS1 and work the heads/cam and you'll make plenty to the rear wheels... mid 400's have been realized by many.

here's a site that searches junkyards http://car-part.com/

there are other sites similar

or try LS1tech.com

Last summer I noticed 2 LS2s with t56(s) for around $5k for each LS2/T56 combo

both with low miles, one was missing the computer though

dude that site is the shiz nit!!!

cool

Nice faq, answered most of my questions!!

nice site

I am currently running the LS1 with a T56 6 speed and a custom Ford 8.8 irs rear diff setup. in my 88 T2..I love my car. It is so much more of a car just because of the tune ability. I m currently building a LS3 with a LS7 dry sump setup on it. It will be a 416 stroker pushing about 650crank hp. My LS1 with head cam is sitting at 535hcrank horsepower right now. I weighed the car in at 2657lbs with full tank minus driver. The 50/50 balance is still maintained because of how the ls1 sits further back and lower than the rotary. I have driven both rotary and V8, Lets just say for the wicked power you cant compare the two, the LS series engines make power easy. Second part, The fuel mileage is amazing. I get 28-29 mpg in the city and 33-34mpg on the highway. Sorry to say, but my old rotary was barley half that. Dont get me wrong i like the rotary, mine was in perfect running order, it was sitting at about 350whp with the rotary, it is like comparing apples to oranges.