2ND generation rx-7 --- v-8 conversion kit.

[FunkLord]

this
hp = Torque X RPM / 5252 (hp is a function of torque)
is a mathematical equation. it goes both ways.

torque = hp x 5252/rpm
this is a real equation, and in this equation torque is a function of HP.

i know how torque and hp and rpm's work. maybe im not very good at explaining it, but that doesnt matter since you know how it works too.

its true that rotary engines lack torque... but torque is a function of horsepower. low torque at low rpm's is just crappy, but in a racing situation low rpm's arent used... so it's not an issue.. however low torque at high rpm's can be compensated with gearing. 150lb-ft@9000rpm with a 5:1 differential will have the about same turning power as 300lb-ft@4500rpm with a 2.5:1 differential... the 9000rpm engine will move through the rpm's faster, but will probbably have a powerband about double the range of the other one... maybe 4000-9000 as opposed to 2000-4500.... if both cars have the same HP, then the lighter one will cross the finish line first. this applies to all engines, not just rotary VS piston... but its also how those hondas can be fast with no torque.

this was my main point, and i still see nothing to discredit it.

[FunkLord]

i just read over that link you sent... and basically it says exactly what i've been saying.
torque = feels better for the driver
hp = what gets you over the line 1st

The Only Thing You Really Need to Know
Repeat after me. "It is better to make torque at high rpm than at low rpm, because you can take advantage of *gearing*." :-)

compare the torque of a 2002 mustang gt to a 2002 honda s2000.

the mustang makes 302@4000 and the honda makes 153@7500. yet somehow the honda is faster. if you take 153@7500 and gear it down to 4000rpm, you get 287lb-ft. so the output to the wheels is a lot closer than it would appear. the honda still makes a little less hp (240 vs 260) and torque, but its also using half as many cylinders and less than half the displacement. overall the car is about 500lb lighter. so using that old saying "100lb or 10hp = 1/10) the honda should be about 0.3 seconds faster in the 1/4 mile.

Car-Stats.com Report for 2000 Honda S2000
Obtained from MT February, 2000
0-60: 5.2 Transmission: Manual
1/4 Mile: 13.8
1/4 Speed: 100

Car-Stats.com Report for 2001 Ford Mustang GT
Obtained from MT June, 2001
0-60: 5.4 Transmission: Manual
1/4 Mile: 14
1/4 Speed: 100

looks pretty close to me. looks like having twice as much torque didnt overcome the similarities in the HP. the mustang might *feel* faster, but the s2000 is faster.

[blsmooth]

do you guys have any good sites for kits. I have a 95 rx-7 with a perfect motor, but a wrecked body... Any suggestion? It's not easy finding a body. I figured a kit would look hot?

[VR6Turbo]

S2000s hit 60 in about 5.8 if you are a really good shifter.
Mustang GTs in 6.0.

I agree that putting a piston engine in an RX-7 is sacreligous. The rotary is a huge attraction to the RX-7 for me. It has so many advantages over reciprocating engines. It also sounds much better!!

[Chris V]

I agree that putting a piston engine in an RX-7 is sacreligous. The rotary is a huge attraction to the RX-7 for me. It has so many advantages over reciprocating engines. It also sounds much better!!

Advantages in a 2800 lb car that mean that it has 143 hp and less torque, lower lifespan due to overwork, and a greater rebuilld dollar amount per hp? Side, tip, and apex seals that can't stand even a single instance of detonation? Horrible fuel mileage for it's displacement?

It's a great engine, but it's still just a car, not a religious shrine. And 143 hp isn't the best tool for that job. Oh, and make one make 300+ hp, and the reliability goes straight in the toilet.

Leave the rotary in seriously lightweight cars, like RX3s, R100s, and early RX7s (or Austin Sprites, triumph Spitfires, Fiat X1/9s, and some kit cars, like Lotus Super Seven replicas).

And after years of racing various rotary powered cars, and listening to built ons on the street day in and day out, I don't think the weedwhacker-on-steroids sound is all that pleasant.

[VR6Turbo]

First of all the FD3S didnt have 143 hp. It was 255hp. 215 ft/lbs of torque. Take a Mustang GT 260hp, 300 ft/lbs. the Mustang hits 60 in 6 seconds. the RX-7 in about 5. With less power, and a smaller powerband. Camaro Z28s get to 60 in a little over 5 seconds.

The rotary engine is not as cheaply built up as a V8. They also dont have the ability to make the same amounts of power. That doesnt mean that you should put a V8 into an RX-7. If you have the money to keep up a rotary its not a problem though.

[VR6Turbo]

How old are all of you Anti-Rotary bigots? I can imagine that an older adult would lean more towards the tried-and-true,classic V8.

im 20 years old, I like the "weedwhacker on steroids" sound, i like the feeling when your boost comes up, I like having an engine that is not the same as EVERY other damn car on the road.

I dont care if you want to put a 5.0 Mustang, LS6, L-88, even a Flat 4 Beetle engine in YOUR Rx-7. I would never put one in MINE. It doesnt mean YOU are right, it doesnt mean IM right. Its a matter of opinion and personal tastes.

[Chris V]

Originally posted by VR6Turbo
First of all the FD3S didnt have 143 hp. It was 255hp. 215 ft/lbs of torque. Take a Mustang GT 260hp, 300 ft/lbs. the Mustang hits 60 in 6 seconds. the RX-7 in about 5. With less power, and a smaller powerband. Camaro Z28s get to 60 in a little over 5 seconds.

First of all, the STOCK engine in my FC3S had 143 hp. If you're going to talk about a car like mine, know what you're talking about. It was a NON turbo 2nd gen RX7. 1986. 16 second quarter mile time, stock.

But to go on about the hp of the rotary being better due to the slightly quicker time stock of a vastly more expensive twin turbo FD3S (the 93-newer version) completely ignores that the RX7 has lighter weight and considerably shorter gearing. Simply putting the final drive gear ratio of the RX7 into the Mustang would make it quicker.

The rotary engine is not as cheaply built up as a V8. They also dont have the ability to make the same amounts of power. That doesnt mean that you should put a V8 into an RX-7. If you have the money to keep up a rotary its not a problem though.

Ok, so I should be able to afford a $2500-4500 stock rebuild on a car that was only worth $2000 in stock form? Why should someone have to be rich to own a $2000 car? Just so they can go around saying "I have a tiny little engine, and teenage boys that worship it will like me?"

How old are all of you Anti-Rotary bigots? I can imagine that an older adult would lean more towards the tried-and-true,classic V8.

im 20 years old, I like the "weedwhacker on steroids" sound, i like the feeling when your boost comes up, I like having an engine that is not the same as EVERY other damn car on the road.

I dont care if you want to put a 5.0 Mustang, LS6, L-88, even a Flat 4 Beetle engine in YOUR Rx-7. I would never put one in MINE. It doesnt mean YOU are right, it doesnt mean IM right. Its a matter of opinion and personal tastes.

First you say that I'm an anti rotary bigot, then say it isn't a matter of me being right or you being right. I've owned quite a few rotaries (from RX2s and RX3s to RX7s, and put rotaries into cars that didn't have them, stock). Just because on one of my cars I wqanted to make it have huge power and torque to go along with the excellent chassis, and didn't want to have to spensd a huge cunk of change to do it, does NOT make me an Anti-rotary Bigot! I LOVE rotaries. I just don't think they are god's gift to teh automotive world. Cars are not religious shrines, especially in mass produced, stock form.

I've owned over a hundred different cars in the past 20 years. From rotary engine cars and tiny 4 cyl traditional sports cars, to 600+hp musclecars. My RX7 with the V8 was VASTLY more unique than the legions of stock 2nd gen RX7s out there. How DARE you say that merely having a rotary car makes your car unique! A one off custom is MORE unique, and got more respect from more people than a clapped out GXL would have!

[MyGTR34]

You can find those conversions but theyre only in like Puerto Rico where the rotary engine was and still is very popular. I personally wouldnt waste my money on a conversion like that because of the possibilities that you have with the rotary engine but...

[VR6Turbo]

Its very nice that you have a FC3S, good job, I understand buddy. Calm down. You keep complaining about the power of the car, "....143 hp is not exactly the tool for the job."
I was just bringing up the VAST difference in performance between 2nd and 3rd gen.
I called you an Anti-Rotary Bigot because you seem to believe that the engines are better off in a junkyard rather than in an RX-7, replaced by some lo-tech V8 out of a 5.Slow. Everytime someone made a post talking about the rotary, you made this HUGE elaborate post, quoting EVERYTHING that they said, then telling them how wrong they were. If you were so ENORMOUSLY concerned with the cost, why didnt you just cut the floorboards out and make yourself a FLINTSTONES car!!!!
Yes, you probably did the right thing with your old a$$ blown engine 2nd gen.

[MyGTR34]

"From what I can tell it seems like Chris V has a lot of pent up anger directed towards rotary engines. This could trail from his childhood past, maybe his father owned a rotary, and mistreated him with it, or maybe he just couldnt take the power at such a young age. Or Maybe he had a bad experience as a teenager when on prom night he and his date in his big Mustang 5 point slow pulled up next to an FC3, and got the living crap beat out of him. There are several contributing factors Im sure, but there is still only one reason for Chris V to not like Rotary Engines, he cant hang with the rest of them, cuz theyre already across the finish line baby!" these and more words from Dr. Phil when we return.

[VR6Turbo]

LOL!!!!!!!!!!!!!!!!!! That was great. You shouldnt bring those horrible memories back to him, it could trigger some kind of psychotic breakdown. Oh wait, by the looks of it, it already happened!!!

[MyGTR34]

I want Chris V to go to "Those Annoying RE Haters' and to respond so that we dont have to keep coming here to continue this conversation. :frog: :monkeypis

[Chris V]

Originally posted by VR6Turbo
Its very nice that you have a FC3S, good job, I understand buddy. Calm down. You keep complaining about the power of the car, "....143 hp is not exactly the tool for the job."
I was just bringing up the VAST difference in performance between 2nd and 3rd gen.

You made the ASSUMPTION that every RX7 is an FD3s, and that EVERY rotary is a TT 13B or 20B. The power of my car when I did the conversion was exactly Zero HP.

I called you an Anti-Rotary Bigot because you seem to believe that the engines are better off in a junkyard rather than in an RX-7, replaced by some lo-tech V8 out of a 5.Slow.

You seem to feel that I feel that way because you only read as far as seeing I put a V8 in my car, and no goddamn farther. You made a WRONG assumption and started insulting me. Then you want ME to "calm down". Sheesh. You COMPLETELY missed ALL the references to how many rotary cars I've owned and enjoyed.

And do we have to go into the whole Low Tech vs High Tech crap again? Until you actually HAVE any experience in car building, you don't have a clue. YOur narrowmindedness shows up in your rather BS nickname for a Mustang 302 (which is proven daily ion dragstrips and road race tracks around the country).
The Ford 302 is a thinwall desing that is extremely compacrt, not just for it's displacement, but for automotive enignes in general. It got that way by using more modern technology than the average OHC engine (hell, the first DOHC enignes were around in 1912, and even the US had a production DOCH, 4 valve per cyl, alloy engine by 1932! The thinwall pushrod V8 came from technology developed dacades later (about the same time Felix Wankel was developing the rotary from a design patented in 1908...)

Everytime someone made a post talking about the rotary, you made this HUGE elaborate post, quoting EVERYTHING that they said, then telling them how wrong they were.

Because, like you , they WERE wrong, and didn't bother to read completely. Maybe your short attention span is WHY you don't know squat...

[Chris V]

Originally posted by MyGTR34
"From what I can tell it seems like Chris V has a lot of pent up anger directed towards rotary engines. This could trail from his childhood past, maybe his father owned a rotary, and mistreated him with it, or maybe he just couldnt take the power at such a young age. Or Maybe he had a bad experience as a teenager when on prom night he and his date in his big Mustang 5 point slow pulled up next to an FC3, and got the living crap beat out of him. There are several contributing factors Im sure, but there is still only one reason for Chris V to not like Rotary Engines, he cant hang with the rest of them, cuz theyre already across the finish line baby!" these and more words from Dr. Phil when we return.

This of course is a PRIME example of someone thinking they are smart, but NOT FU(KING READING!

When I was in high school, I was racing both my 429 powered Torino GT AND my rotary powered RX3. That RX3 is STILL one of my favorite cars. '73, with a '78 12A, heavy street port, Racing Beat header and Holley carb kit, RX7 5 speed, 4.88 rear gears. Very quick, and very good handling. But not very streetable, with no useable power below 3000 rpm and a lightened aluminum flywheel.

Sorry, asshole. I love rotary cars. It just happens that ONE of them I owned got a built V8 when it died... Sorry you're too stupid to be able to handle that.