GTR

iTrader: (6)

Back then,
If you told me to swap a V8 in my RX-7, I would tell you to **** off. And when I saw people's V8 swaps, I just shook my head. A RX-7 needs a rotary!

Now,
Advancement in the LS series V8s now, and it deserved another look.
We're no longer talking about cast iron blocks with a huge carbs sticking out of the hood or stupid hood cowls. We're talking about all aluminum engine with a 5.7L, 6.2L, or 7.0L and swap kits that make it almost painless. No more hood cowls and holes in the hood where the air cleaner sticks out.

About me..
I love rotaries.
I've always loved rotaries.
I knew more about rotaries than regular piston engines when I first got into cars.

Being able to just rev the car so high and have that turbo kick in, it was fun...
All the rotary people I met through years were extremely cool and helpful. It's like we were a different breed and I'm pretty sure most of you guys can relate.

When I had my FC RX7, it was at 130k and it had low compression. I rebuilt engine with pretty much all new OEM parts except rotor housings and rotors. From OEM apex seals, springs, oil control rings, side seals, bearings, oil pump, chain, gasket set, and having the housings lapped. Then adding a upgraded turbo, wastegate, manifold, lines, etc... after it was all that, It was probably 5-6k and that didn't include the standalone and intercooler it needed. So I probably would have spent around 8-9k after all that. If I dyno'd it, it probably would have put out 300-350hp. I sold the car before I had a chance to really finish it.

I had the itch a while back and I wanted to get into it again.
I looked around and found a clean FC that sat for a few years.
I bought the car and sure enough, it had a blown coolant jacket wall and the housing needed to be replaced, also needed a rotor housing.
I searched around for a month, looking for parts and what mods I was going to do to the engine and priced out the parts for the rebuild. It was about 1500 in seals and it was pretty much deja vu. It was going to be the same story all over. Probably another 7K+. I asked myself if I really wanted into invest into another FC rotary. So I said I would invest that kind of money into at least a FD and here was my deciding factors.


Cons:
3.5k engine rebuild (could be cheaper but I figured replace as much as possible)
2.5k turbo/manifold/lines
2k Standalone
1k Racing Beat Exhaust system.
Turbo Lag -
No emissions (stinky exhaust),
Premix every time I filled up
Poor gas mileage
Finding parts can be a chore and when you do, it's pretty damn expensive.

Pro:
High Revving Rotary Engine with Turbo.
Big power out of small engine.
I don't have to upgrade pistons, rods, valves, valve spring, camshaft and retainers.
Being around other cool rotary owners.
I guess that's it unless I'm missing something.

V8 Cons:
2-4k LS3 Engine or 8K for EROD Smog legal LS3
1-1.5k T56 Transmission 3.5k for T56 Magnum
1.2k for Factory ECM or 2K for Holley EFI
4-6k Swap Related Parts (headers, radiator, fuel pump, clutch master, hoses, lines)
2-3k Rear End 8.8
Handling of the car will be changed due to engine being heavier and rack placement. They make bump steer kits but It probably wont fix it completely (especially if you have a lowered car)
Camshaft, valve springs, retainers, valves, etc.

V8 Pros:
350-400 easy horsepower
TORQUE!
Better Fuel Mileage
Can be made SMOG LEGAL with the EROD kit
6 Speed
Buying parts is super easy. SUMMIT and JEGS has so many parts for LS engines. Buying replacement parts is easy also. Going to autozone, dealership, etc..

While the high upfront cost of the V8 swap a lot, but if I planned to keep the car for a long time, another rotary engine rebuild will offset that cost by a lot

I think the biggest pros are

- CARB legal and never having to worry about CA STATE REF.
- Gas mileage
- Torque
- More reliable than rotary (Most rotary owner knows this but won't admit, the more mods you do to the rotary, it will become less reliable ) This happens with most engines.

If I had a choice between a stock V8 and make 350-425 hp or a modded rotary for the same numbers, I would chose the V8.

real1st

iTrader: (3)

I swapped my rotary with a LS1/T56 combo years ago, less headaches, especially with emissions. Less issues with parts, worrying about everything. Now I can actually drive the car... There will always be issues, but thankfully, rebuilding the engine is not it.

tbkonwso

iTrader: (4)

i drove my v8 rx7 to snow boarding in lake tahoe... and the following week drove 10 hour to vegas ... you get in and just drive...you stop worrying period. bumper steer does mess with the car a bit, but proper alignment..adjustable ps, tire/wheel setup will bring the handling back to 80-90%... 80-90% as in..how the rotary rx7 felt like.. not as a downgrade car handles well powerband is great ... either way

gnx7

iTrader: (10)

I built a basically stock LS2 bottom end aside from rod bolts and stock LS3 heads/intake for my old FD race car when I sold it. Made 460rwhp/420rwtq with a baby cam and compression good for 91 octane. The car has set fastest time of the day many times and over the past 2 years of hard racing has yet to have issues. It does run an ARE dry sump system. I kept the rev limiter to 6600rpm for longevity sake. It runs $250 dual springs from Brian Tooley and one of his cams.

These motors are work horses and if you keep the RPMs down they don't need any exotic parts to make good power and last a long time.

Natey

iTrader: (19)

I love love LOVE the sound of a ported 13b singing past 8k, but 400lbs of smog legal torque is hard to argue with.

7dust

iTrader: (14)

Eh, my honest opinion is that V8 RX cars suck *****.

phdofski

iTrader: (4)

My guess is you've never driver 1.

jimbo03886

Some people are just dead set on a rotary. If they want to be closed minded then so be it.

rafgonz

iTrader: (3)

Great assessment GTR! I have very similar views to yours.

I am on my second FD. The first time around I did an LS1 swap. Quite honestly I did not see a big difference in terms of handling, then again I am not the best driver out there. On autoX days I was getting similar numbers to another rotary FD.

Even though rotaries can be reliable, they require extra attention in my opinion. I cannot begin to tell you how often I would drive my other vehicle from South Carolina to Florida when I had my rotary. Once I swapped the LS all I worried about was having gas in the tank.

Recently I got another FD, it has a rotary. Maybe it just this car but I am starting to miss my v8. The other day I decided to go for drive, I forgot something at home so I made the terrible mistake of shutting the car off when it was cold. Flooded.

Maybe I am getting old, or maybe I am tired of the complains from my lady friend of how my new FD doesnt have a/c, she stinks like gas, or she cant hear the radio over the exhaust, etc etc. At the end of the day I am having a hard time not switching to another v8.

cone_crushr

iTrader: (18)

I really appreciate the frank, intelligent , well reasoned post GTR. But whenever I hear the advantages of a V8 (and there are plenty), seems that people don't get it. Just buy a Vette and be done with it. You want torque, an RX7 is not the car for you. You want to drag race, buy a Mustang or Camaro.

Headaches come with the territory. "Oh is't so easy to deal with a V8, I just stab the throttle and the car goes." Jesus. The RX7 is an exotic car, of course it requires extra attention. Turning it into a bastard Vette is the wrong answer, despite spreadsheets hinting otherwise.

LargeOrangeFont

iTrader: (7)

Headaches come with what territory - Running a rotary engine? Yes you are right, and that is why people swap them out for V8s.

What is it that you think people are not getting? The RX7 is a good car with a finicky motor. Yes you can make the rotary work well but it is expensive, and one overheat, one knock event, and it is done, you need a new motor. The car is by no means exotic. Yes the FDs were not high production cars, but they made quite a few of them. If you are worried about people ruining these cars, talk to the drift guys.

My v8 FC is more reliable than any other FC track car (with similar power) than I have seen. I have over 4000 track driven miles on my setup to date with zero drivetrain related issues. It is a 30 year old car I can beat on all day, and it runs with modern high end sports cars. It does not overheat, it makes over 400 to the wheels and it runs on 91 pump gas that I don't have to premix. Oh, and the gas mileage is about double that of a 400WHP rotary.

The question is - How many guys that had an Rx7 with with a functioning rotary engine, went V8 and subsequently said they don't like it and want to go back to a rotory.. That number is near if not right at 0.

It is not that you cant make a rotary with that level of power, you will just waste a lot more time and money doing it. A 400WHP rotary is just as fast as a 400WHP v8, so why not just SAVE yourself the headaches.

I get nothing but positive response when people come over to look at the car after seeing it run, but I'm sure people that have some problem with it are not going to walk up and tell me.

Narfle

iTrader: (16)

God forbid you attempt to tarnish the perfection that is a v8 FD. Don't butthurt these nice people any more, they were already butthurt by the rotary god.

RotaryEvolution

iTrader: (30)

eh, my car has been the most reliable thing i've owned, and not far off the marks you gave and back when i built the last engine(did replace it after about 80k miles) i wasn't exactly using new or even the best used parts. and it got almost 24mpg on the highway until that engine lost enough compression that it just wouldn't start reliably anymore.

course it probably woulda lasted longer if i didn't run it 3 full tanks without any premix a while back...

i don't hate V8's, but i still would never do the swap because the rotary engine once simplified is easy to work on and can be made semi reliable. mostly it is in simplification, not redundant safety measures that can fail and actually cause issues. i haven't touched the tune on it in, what? 6 years? i don't even run a wideband in my car, it comes out once i have made adjustments.


i do however see a lot of people build a rotary rx7, dump a bunch of money into it and less than 5% from completion they get cold feet and sell the car in worry of blowing it up. or they do a hacktastic job building the car, blow it up, flail their arms and bitch fit that the rotary is junk.

valley

iTrader: (1)

Considering the nature of the automotive world in 1995, the cost of the RX7 compared to other cars, and its performance, yes, one could easily argue that it qualifies as an exotic without even mentioning its engine.

And you've been very lucky LOF. Most other guys who run cars with LSx motors manage to blow them at drag strips; even when they do everything right. It's also not difficult to understand why an engine that is more stressed than another at 400whp might last not quite as long assuming everything else is equal. Although, a bit ironically, rotary engines seem to last quite a bit longer [racing] when in lower whp configurations than similar piston engines. Go figure.

And a swap isn't a headache? Or a money pit? A 400whp rotary will always have an advantage over a 400whp LSx swap: weight. The engine weighs more, the trans weighs more, the 8.8 diff weighs more, etc.

LargeOrangeFont

iTrader: (7)

It was about as much as a Corvette in 95. Calling a RX7 an would be like calling a Corvette, 300ZXTT, or a Supra an exotic car.

I do agree, the non turbo rotaries are pretty bulletproof if taken care of. I blew a coolant seal in mine on the track running the oil above 250F.

You kind of made my point for me.. It is a lot easier to run an engine designed to make more power stock, than to run another engine modified to within an inch of its life to make the same power. There are SCCA T1 class c5 Z06 Vettes that run the OEM engine with over 100,000 miles on them. Mildly built LS engines are about a bulletproof as an NA rotary if prepared and run correctly. My setup is pretty close to a stock LS1 configuration, with durability modifications to the oiling system and valvetrain.

And unfortunately you are wrong about the weight on 2 of the 3 counts. An LS1 weighs about as much as a turbo rotary once you add the larger turbo, intercooler, piping, and other associated hardware to it. Some combinations will weigh more and some will weigh less. A stock turbo rotary is indeed lighter than an LS engine however. Call it a 20-30 lb difference at most depending on what we are comparing.

The t56 trans weighs about 50 lbs more than the turbo rotary 5 speed. It just does, but its low and in the middle of the car.

The 8.8 conversion is within 2 lbs (mine was 2 lbs lighter) than the TurboII diff and axles. Remember the 8.8 case is aluminium, while the TurboII case is iron.

My car weighs just under 2700 lbs wet with a full tank of gas, ready to go. That is with 51.8% on the front wheels. The big brake kit I have added 25 lbs to the front axle, so with stock brakes I'd nearly be at 50/50. I have no interior in the back of the car, if I did it would probably net out perfect.

As far as being a money pit, tell me how being on your 3rd or 4th rotary engine is not a headache or money pit. There are very few people that are on they 3rd or 4th LS engine without doing things seriously wrong.

LargeOrangeFont

iTrader: (7)

The below is from the "Lets Talk Weight" thread in this subforum. ZDan had weight information before and after the swap for his FD

valley

iTrader: (1)

Last I heard the 95 rx7 cost more than the 95 ZR1 due to the yen having a large gain compared to the dollar at the time. And considering most exotics, barring actual super cars, were rather crappy at the time... well, you get the idea.

And you've been lucky, the LS forums have plenty of the rotary equivalent of people who have engines that blow up or have incessant problems for little to no apparent reason.

LOF, we've been through the weight thing before. I don't want to get into a pissing contest over it but the fact remains that all those parts weigh more than the OEM Mazda equivalent. The 13bt OEM fully dressed weight is ~380lbs while the LS1 OEM fully dressed weight is ~500lbs. These are facts and I know that we hashed this out months and months ago in another thread. Doesn't matter where they are part for part the weight is greater. pre vs. post swap weight is simply a way to bring unaccounted modifications into the picture and muddy the issue.

LargeOrangeFont

iTrader: (7)

A ZR1 was ~$70k. FDs were just under $40k. Do a google search for FD window stickers. That is not an exotic, it is a sports car. Car prices do not swing wildly with currency valuation. A manufacturer would not sell any cars that way.

If you believe a rotary is more reliable than a LS v8 engine I'll let you continue to live in your fantasy land. Don't bother to look how many RX8s with 60-100k miles that have blown rotaries or are on their second engine.

We are not talking about a stock 13bt. If you want a 200 HP car, keep your rotary. Yes it is lighter than a V8. If you want a 400-500 HP of rotary power you are ADDING weight to do it. After adding dual oil coolers, front mount intercooler, larger turbo, wastegate, etc you are within 50 lbs of a fully dressed LS1. If you aren't running AC or PS on an LS1 the weight drops 25-30 lbs. If you run an aluminium flywheel, it takes off another 30 lbs, but you can also do that on the 13bt.

Even if it does weigh a bit more it clearly works, and does not upset the balance of the car.

RotaryEvolution

iTrader: (30)

pick the 2nd worst mazda rotary engine in history as an example for bias. good job.

didn't realize this was the 8 club forum.

LargeOrangeFont

iTrader: (7)

Ok then use whatever rotary engine you want. You can't tell me any of them on average last longer than an LS V8. This is an inherently biased comparasin because we are talking about a V8 designed in 95-96 vs a rotary that was designed much earlier.

My NA FC was on its 2nd engine when I bought it. The car was stock and driven by a woman.

How are rotary engines getting worse over time and not better? I picked the RX8 because it was the latest variant.

Again I ask where are the droves of guys with V8s coming back to rotaries if it is so bad? Some of the higher profile FD guys have went V8 and love it.

LargeOrangeFont

iTrader: (7)

I know this is a religious debate and no ones mind is going to change here. But these cars are not "ruined" by putting a V8 in them. That is the only point people should realize.

If you think a V8 ruins the car because of weight, then putting in a 3 rotor ruins it more right?

That's where the "car ruining" argument falls on its face. A 3 rotor is unquestionably heavier and further forward than a V8, and therefore further ruins the car.

valley

iTrader: (1)

LOF, the thing is that it is not a religious debate at all.

Facts have been stated by both parties and it appears that you want to mitigate the LSx's weaknesses. It is not some paragon of reliability. Is the rotary less forgiving of shitty tunes and lack of maintenance? Sure. Is the LSx, outside of 100% racing conditions, more likely (key word) to last more miles than a rotary? Yes. I think we can all agree on that. But it IS heavier, as is the trans typically used with it. By itself that means, without question, that if everything else is equal and "ideal gearing" for either engine is used, the non-LS car will be faster. End of Story. And we all know a 100lb (using your numbers) weight penalty is a lot in racing.

The other reality is that the rotary has nowhere near the R&D that piston engines have. We could all go back and forth of the why and meaning of it but that alone is a huge handicap as well.

GTR

iTrader: (6)

The number thing that made me switch was driving an actual LS swapped FD.
I was on fence before if I should really do it or not.
The advantages of the V8 are pretty clear on paper but being able to drive one completely changed my mind.

RotaryEvolution

iTrader: (30)

if you've ever ridden dirt bikes you can see a difference in how a 2 stroke runs versus a 4 stroke. the engines have different powerbands but are generally on equal footing otherwise.

why beat the dead horse again? some people like the high rev smooth feel of a rotary as those who prefer 2 strokes. some like the ground thumping shake of a V8 pounding the earth with displacement as 4 strokes.

different strokes for different folks. personally i feel a V8 is more complicated and harder to work on when things go wrong, but then again i don't have 20 V8 engine blocks sitting in my shop either.



if you can't build a rotary, don't have spare parts on hand, don't know how to tune or fabricate i can certainly see the appeal to a swap. a rotary in general won't last quite as long as a V8, but the differences of a properly built setup are not as bad as you guys are claiming...

and yes, the RX8 series 1 was a step back in the reliability of the rotary engine, and isn't a proper comparison benchmark.

GTR

iTrader: (6)

If I wanted to own a Corvette, I would have bought one. I made no mention about even drag racing the car. If there was no V8 swaps available, I would still be driving the RX-7 with the rotary. I've always love the FD when I first saw it when I was in middle school.

On a side note, I'm hoping to meet a 3 rotor owner and tell them you ruined the car. I would love to see their reaction.

I still love rotaries and even with the V8 hate, I still love you guys. The RX-7 community is a great , v8 or not.