RX-7 Engine

:confused:

Hey i own a 1994 Red RX7 TT and was thinking of the new Renesis Engine in the RX8 and all the other rotary engines that work in the RX7 and was wondering in your opinion what the best engine for the RX7 is?

1.) your profile says you own a 1993 with a VeilSide Body Kit? Veilside bk's are junk...
2.) if you can find a renesis, it would be an awesome engine to put in a third gen. I'm going to do this in a few years when dumbasses start wrecking their RX-8's, but until then, the engines are going to be a lot of money. But with your car list, that doesnt seem like a problem for you.

The best thing to do would be to keep the engine u got. Rebuild it and put a GT3540 on it.

I say keep the engine you have or buy another one just like it. The Renesis engine will probably be more reliable, but I'm not sure it has been proven yet. Even if it is more reliable, there are still no turbo's. I think the Renesis is an awesome engine, don't get me wrong, but it needs a turbo or two. That is just my opinion.

One more thing, doesn't the 93 TT engine have more hp stock than the Renesis??? I have it in my head for some reason that the Renesis has 250 hp, correct me if I'm wrong, but doesn't the 93 TT have 255 hp stock??

Originally posted by 13BDriver

One more thing, doesn't the 93 TT engine have more hp stock than the Renesis??? I have it in my head for some reason that the Renesis has 250 hp, correct me if I'm wrong, but doesn't the 93 TT have 255 hp stock??


Shouldnt that tell you something? A n/a engine has only 5 hp less than a twin turbo engine... Slap an exhaust onto the renesis and you've got close to 300 hp.

Yes, this is true. The n/a Renesis has only 5 less hp, and with an exhaust, I'm sure it is possible to get close to 300 hp. But...here are my thoughts.

Turbo engines have more potential than n/a engines. A BPU twin turbo RX-7 is easily capable of 300 hp, and this is with just exhaust, boost controller, and intake. I'm not exactly sure of the hp numbers this can achieve, but I would be willing to bet that a BPU RX-7 would go easily above 300 hp, depending on how much boost that car was making. Anyway, this 300 hp BPU RX-7 still has many more things that can be done to gain hp. You could upgrade the twin turbos and put bigger ones on, this would gain considerable horsepower. I don't know why anyone would do this however, because you could do a big single turbo and make even more power. I'm not saying that there isn't anything you can do to an n/a engine because I know this isn't true. Just as far as building a car goes, there really aren't a whole lot of things to do to add considerable hp to a n/a engine. Say for example you put an intake, exhaust, pulleys...and so on, let's just go to say you put on every bolt on possible on the renesis, the potential for horsepower is no where near as great as it is with the tt engine.

please bear in mind that the main differenc between the N/A and Turbo Rotary is merely 2 things...

The turbo's have lower compression, and a turbo...

Therefore N/A's have more potential, because they do not have a turbo... yet....:biggrin:


eg, what happens when you put that great TT system on a renesis and work out all the engine management bugs...

LOTS OF POTENITAL HUH!!!!

I'm just being a smart ass and agreeing with you (13BDriver)

Also bear in mind things like power to weight ratio's sure the 13B-REW only has 5 less HP, but how much more does it weigh? How much more heat does it generate with that great tt system? therefore, how much more room up front is being taken up by the volume and weight of more heavy duty cooling devices (heater core, oil cooler(s) radiator, ast, massive front mount intercooler... etc)
On that note remember the Renesis is physically smaller.

Again, I would simply buy the renesis. tear it apart, port the shit out of it, with the money i save from all the ancilary turbo stuff buy a great aftermarket ECU and dyno/track tune the hell out of it...


the problem now is waiting until the Renesis decreases in price enough for all this to be feasible.

My main reason for prefering the N/A engine is the power band... much much flatter, and wider torque curve, than even the super smooth seemingly transistionless TT system on the 13B-rew.


Have you driven a Combo-Port lately?

Don't get me wrong, I love the Renesis engine. I love that Mazda brought it back and hopefully, finally worked out the rotary engine. So don't think by any means that I am dissing the renesis or anything like that. If I were going to build a car to autox, I would go with the Renesis engine if it were at this time feasible. This engine would make a much better autox engine because of the flatter powerband and wider torque curve.

But...didn't the guy that said he wanted to put a Renesis in his car have a 93 or 94 TT? Correct me if I'm wrong but don't those have the perfect 50/50 weight distribution also, even with all of the heavy cooling devices and such?? I'm not trying to argue with you dayna240sx, just trying to make a point. :biggrin:

Anyway, for me, I have to go with the turbo. My friends around here all have turbo cars, and if I am even going to come close to competing with them some day, I know that is my only option. My best friend has a 03 WRX with up-pipe, downpipe, turbo back exhaust, VF22 turbo, Link Engine Management, and a supra fuel pump. He ran a 12.9 at the track. His car doesn't fuck around. Also, I have a friend with a Supra with an SP74 turbo and too many other things to list, and when it went on the dyno, he had 805 hp at 5,000 rpm, but the radiator started spitting fluid so they had to let off. I know there is no way I could ever build a naturally aspirated car to come close to them, without going through the headache of converting the car into a turbo car, which is going to cost lots of money and consume lots of time to get everything right. Hell, I was thinkin' about putting a turbo on my Civic, but even if I did get it on there, it wouldn't be worth the time because it would still be slow unless I wanted to throw like 15 more grand into the engine after I got the turbo setup. So, I guess my point is, if you have a tt engine, it is much easier and less costly to build than it would be to build the Renesis engine.

Having a Renesis engine in an FD3S would be very nice. No turbo-lag.. While the FD's twin scroll turbo greatly reduces that lag, it still exists. I would give up 5 hp from a turbo for almost the same amount of real engine power. And if you wanted more hp in your Renesis, you could add a turbo.

Originally posted by gawdamu2.0
Having a Renesis engine in an FD3S would be very nice. No turbo-lag.. While the FD's twin scroll turbo greatly reduces that lag, it still exists. I would give up 5 hp from a turbo for almost the same amount of real engine power. And if you wanted more hp in your Renesis, you could add a turbo.

Im not here to flame you...

Ive heard the RENISIS suffers from S200 syndrome, where the torque is above 6k rpm, id give up a bit of lag to have low end torque

Ive also heard the RENESIS is diffucult to turbo because the exhaust manifold is a weird design and bends around the frame...dont quote me, I think it was in SCC...

doesnt swin scroll mean a single turbo with some fancy trick to it, like the STi and new Legacy, whereas an FD would have a sequential turbo?

Originally posted by Dorikin


Im not here to flame you...

Ive heard the RENISIS suffers from S200 syndrome, where the torque is above 6k rpm, id give up a bit of lag to have low end torque



As an aside, the S2000 actually has more torque than most 2 liter non turbo engines, and has more torque down low than most 4 cyl sports cars have had, ever. While the PEAK torque figure is pretty high, the actual torque curve is so flat that 80% of the total torque is available by 2500 rpm. In fact, it makes more torque at 2500 rpm than a stock 2.7 liter VR6 VW engine...

Here's aplot. Notice how flat the S2k's torque curve is (these are rear wheel numbers, and pretty good for a 2 liter sports car)

http://www.comptechusa.com/images/dyno/s2kintake.pdf

http://www.randdmotorsports.com/images/projectcars/dynopulls/dyno_stockpull.jpg

Hmm, thats not bad. My dad had a S2k (borrowed it off a friend working at Honda) and it wasnt lacking on power, but a bit more torque all round would be nice.

I love how this guy never seems to reply to his own threads... :sly:

lmao, 50 hp from exhaust on an N/A rx7 ... thats funny

Have you not heard of the triple rotor 20b.
It is able to be fitted to RX7 RX3 etc.
UP TO 1000HP IN RACE TRIM.
i HAVE SEEN ONE PULLING 9OOHP ON 24PSI BOOST

Yes, ive seen one in real life.

Originally posted by 20bgod
Have you not heard of the triple rotor 20b.
It is able to be fitted to RX7 RX3 etc.
UP TO 1000HP IN RACE TRIM.
i HAVE SEEN ONE PULLING 9OOHP ON 24PSI BOOST

A triple rotor 20b is heavier than a pushrod V8, and longer. it sits farther forward in teh engine compartment than teh 13B OR a V8 would, making the car far more nose heavy. It's over 400 lbs in turbo form, and it sits ahead of the front axle. It's VERY expensive in the US, yet you dont' get a lot for that money. OF the handful of people who have done that conversion to RX7s in the US, the cheapest was $15k. And that was a stock 280 hp version. A guy I know here at work has a 400hp one in an FC and cost him over $30k to do.

A 20B does the one thing to the car that a V8 conversion doesn't: messes up the balance of the car. And it's still unuseable on the street over 500 hp...

Originally posted by Chris V


A triple rotor 20b is heavier than a pushrod V8, and longer. it sits farther forward in teh engine compartment than teh 13B OR a V8 would, making the car far more nose heavy. It's over 400 lbs in turbo form, and it sits ahead of the front axle. It's VERY expensive in the US, yet you dont' get a lot for that money. OF the handful of people who have done that conversion to RX7s in the US, the cheapest was $15k. And that was a stock 280 hp version. A guy I know here at work has a 400hp one in an FC and cost him over $30k to do.

A 20B does the one thing to the car that a V8 conversion doesn't: messes up the balance of the car. And it's still unuseable on the street over 500 hp...

I'd much rather have an LS1

GImme a JC Cosmos, and a FC transmission :D

I wish I could get a decent JC Cosmo here! Absolutely one of my favorite coupes on the planet. 20B turbo in a beatuful body. Yummm!

http://www.rx7-gallery.co.uk/bincosmo/cosmopics/blu_cosmas59.jpg

can i swap a rx-7 motor into my mazda b2200?

Originally posted by Chris V
I wish I could get a decent JC Cosmo here! Absolutely one of my favorite coupes on the planet. 20B turbo in a beatuful body. Yummm!

http://www.rx7-gallery.co.uk/bincosmo/cosmopics/blu_cosmas59.jpg

A friend of mine in baltimore almost bought one for sale in Florida.

is there anywhere that sells the Renesis engine besides mazda sealers..and a Renesis would be nice in a FC3S...i would take one over a 240sx

Originally posted by Dorikin


Im not here to flame you...

Ive heard the RENISIS suffers from S200 syndrome, where the torque is above 6k rpm, id give up a bit of lag to have low end torque

Ive also heard the RENESIS is diffucult to turbo because the exhaust manifold is a weird design and bends around the frame...dont quote me, I think it was in SCC...

doesnt swin scroll mean a single turbo with some fancy trick to it, like the STi and new Legacy, whereas an FD would have a sequential turbo?

Correct. A twin scroll turbo means a single turbo with two exhaust intake scroll passages. I confuse myself sometimes. The FD has the two turbos that spin at different RPM's(sequential). My bad.

I do think the Renesis needs more trial, more road time, especially if modifying. But, it's mostly proven, and new exhaust porting is superior except for extra heating of the block.

A journalist [not coolant/lube journals, but literature ;)] stated the exhaust is cooler this way, but I don't want it, I want it hot and direct for a turbo. The side-housing exhaust is helping hold the bang longer and seep an exit slower than the earlier peripheral-port exhaust. Both the intake and exhaust ports of the renesis ask for mild port rounding and a higher rpm limit, so expect >300 hp NA at high RPM, but we're talking about peak horsepower on a >8krpm engine, and power is a product of ignition frequency. Double the rpm, and get a theoretical 600 hp.

I think the renesis's exhaust porting to the side of the rotor, having it snake through more metal before a manifold, is great for non-boost, but a mistake for pumping a turbo. This is a great engine to keep non-turbo.

I'm not going to talk about a super-boosted 20b that pings/detonates at 105 octane with water fogger, with drastic low-rpm ignition retard, with a 1500 ft-lb clutch, at 105 octane, that trashes composite axles and differentials/transaxles for breakfast. Oops -- just did.
Without engine bay modification for a 20b, variants of the 13B are satisfying. But this is funny looking squirrel: http://media.car-videos.com/videos/mazda/dentist_Pac_RX-3_20B.mpeg

I'm a happy TII owner. I use a separate Audi boinger for daily grind.

The RX-8 chassis greatly out-classes in rigidity. The body aesthetics and the novelty rear doors don't encourage me. If the RX-8 were maybe the price of a used FD series, hmmmm....

Yet, lately I've have Porsche turbo on the mind.

"best" is relative to application.

Yay. its another Twin Turbo. I think everybody should just buy PORSCHES.

is there anywhere that sells the Renesis engine besides mazda sealers..and a Renesis would be nice in a FC3S...i would take one over a 240sx


Twin scroll in designs I've seen, are only a secondary set of impeller blades, each a companion with primaries, without congesting the intake with multiple leading edges of blades; it steps the secondary set below the primary, keeping a good open cross-section.

This helps grab new air, trap, and maintain boost compression at the spool-wheel perimeter. An example of weakening the principle -- reduce the quantity of impeller blades, say to 2, and do not increase spool rpm, do not increase blade pitch, and do not lengthen the blade path, do not increase spool diameter, the result is lower boost. However, at that lower boost, e.g., few ounces, the spool efficiency is high from lower impeller drag.

[edited, I babbled even more]
Blades congest the intake. The secondary blades fill-in the wide gaps between the trailing primary blades. Whatever is chosen, it's used to help scoup and hold the compressed air (a fluid).

A triple rotor 20b is heavier than a pushrod V8, and longer. it sits farther forward in teh engine compartment than teh 13B OR a V8 would, making the car far more nose heavy. It's over 400 lbs in turbo form, and it sits ahead of the front axle. It's VERY expensive in the US, yet you dont' get a lot for that money. OF the handful of people who have done that conversion to RX7s in the US, the cheapest was $15k. And that was a stock 280 hp version. A guy I know here at work has a 400hp one in an FC and cost him over $30k to do.

A 20B does the one thing to the car that a V8 conversion doesn't: messes up the balance of the car. And it's still unuseable on the street over 500 hp...

[not an argue/refute/rebut, and yeah this diverges from the original poster; I commented elsewhere about the Renesis...]

Enthusiast conversions.
A small v8 350 has been done for similar cost. The 350 has cheaper and highly available parts in the west.

I'm amazed sweaty guys in t-shirts, hitting the bong ever 5 in Puerto Rico get a 20b to run 9 seconds for under US$1500.

I would not expect a rebuilt 350 to match a rebuilt 20b in a rigorous cross-country endurance race.

The Edelbrock Performer EGR 8.5:1 provides a nice 310hp and 375ft/lb, as a long block with ignition, but nothing else. Cost of engine: US$4,970 I've read a new 20b is a rare commodity and has a disgustingly inflated price of US$20k. The do-it-yourself method is getting the longer 20b crank and stacking another rotor.

So, the 350 gives great performance, but not the same dynamics as the rotary. The highly tuned version of this Edel' 350, ~US$9,000, is ~425hp, and nearly at its absolute ceiling for power and torque for it's internals. Rolloff of torque and flattened power are at 5000 rpm.

This is package almost as throttle responsive as the 20b. Go 6 months or 100 hours in this 350 without precision valve tuning (not in my budget, and multiple re-visits), and you're cranking drops <400hp.

I think the 20b conversion is for the guys that have their investment manager's phone number in redial. But, I wanted to do it last year. I drive an Audi boinger and Mazda turbo wobbler. I can budget about $5k a year on car parts without thinking I'll live my geezer years in unhealthy poverty and isolation, but the 20b is far from a sensible conversion for the street, for me.

The Renesis mounted into an earlier generation would be a nice trick, and for boost: a simple centrifugal supercharger to avoid effort of building in a turbo, when cost matters.
---edit---
Oh, fine kit:
http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&category=36475&item=2441694621

--edit 7/9--
Courtesy AtkinsRotary.com, single turbo 20b performance, nice thrust by 3.5krpm: http://www.atkinsrotary.com/3rotorinfo.htm

http://www.daltonautomotive.com/html/pricelist.htm

Need I say more? possibly... for those of you lazy people out there they're selling 20B's for $4995 AUD

*knows where he's shopping* :iceslolan

Even Nitrous Express didnt want to go with the cosmos engine. They had bought one, but, due to the hard work and amount of money it would take to get the frickin thing street legal and driveable period, it would have been too much trouble.Personally i would love to do the whole conversion thing, but i think id agree with the multi-million dollar company and just make the FD3 a bad a$$ ride with a massive turbo and all the other goodies. But thats just me dealin with what lil money i got, but believe me, if i had the money, Id do it.

http://www.daltonautomotive.com/html/pricelist.htm

Need I say more? possibly... for those of you lazy people out there they're selling 20B's for $4995 AUD

*knows where he's shopping* :iceslolan

Sure. Now get that $4995 20B into the US. And that's a used stocker. Again, by the time that thing gets into an RX7 here in the states, you will have spent over $10k-15k to get a 300 hp engine that weighs as much as a stock 350-400 hp LS1 but sits farther forward in the engine compartment, and won't necessarily last as long. And by the time you get it to match the output of the V8, you'll have spent over $20K.

I built my nearly 400 hp Ford 5.0 powered RX7 for under $3k. And I had no problems with it the 5 years I had it. Cost to benefit ratio is not there with the 20B. At least not in the US. It is in Australia.

I agree with him. You can put an LS1 into an FD for much less than it costs to put a nice single turbo on. Once you sell off your stock stuff it works out to be close to the same.