I also own both an RX8 (supercharged) and a FD. By far, I like the FD best. Even with stock turbo's the FD is capable of mid 11's in the quarter mile, gets much better gas mileage than my RX8 ever did while NA, has less interior rattles, idle's smoother and the motor runs cooler when driven normally. Even the AC works better in my 7 than my 8. The advantage of the 8? 4 doors, softer suspension, simpler engine bay, better emissions. I do like the steering feel better on the 8 than the 7 though.

The 13B-REW's p-port exhaust w/9.0 compression and slight intake/exhaust overlap seems to be the turbo rotary magic ticket as there are several RX7's doing over 400whp reliable and streetable off of 15psi on pump gas. This is even with "old tech" non-ball bearing turbos and they're still completely spooled by 4000RPM with less aggressive intake porting than a stock RX8. The 13B-REW RX7 also gains from a simpler, 2 tract tubular exhaust manifold that can perfectly mate to a divided housing T4 (or T6 -- http://i698.photobucket.com/albums/v...d/DSC04517.jpg ) turbine in an engine bay that actually has space for it. Combine the better (when FI) engine with the more appropriately geared and tougher FD transmission and I find myself with very few objective sports-car related virtues to bring up in my RX8's defense to trump the RX7 with.

 

Nice man!! I think im going with a old school 74 rx3 with a 13b carb supercharged. fix her up as my weekend cruiser and buy a roller/blown engine fd. Only reason i want FD is cause its 2 doors and smaller. Rx8 is a great car just i don't need a back seat. lol i just turned 20 so not married nor do i plan to anytime soon. but FD i build will be a track warrior too, and yeah with right mods it should run better than a boosted 8.

 

the renasis engine is still under developement
OD

 

thats my point, im sure its a great engine. But it is only worth it for those that have bunch of money to test and tune. Im a kid, don't got thousands of dollars to try new things on it. Hopefully one day i will come back to the rx8 series or rx9? But i think right now the renesis won't get much action. Once that 16x comes out i think it will take its light.

 

I just crossed you off my xmas card list

 

Wow Joff, even a SC-ed 8 is not up to par with your FD? Interesting indeed.

Which one would you drive everyday though?

 

Interesting? Never thought a previous FD owner (esp. one whos experienced building theirs up to 425whp) would ever question that assertion.

I still love my SC-ed 8 -- no need to pretend as if this is incompatible with me thinking the FD RX7 is still the best Mazda ever made. I have similar feelings about car colors in that I think one is best, but don't necessarily think the others suck. Along those lines, I ended up with a white FD mostly by chance, but now that I've had it awhile, both my wife and I are now extremely confident it is by far the best color..... Funny how that works... makes ya wonder if its really the best color or is it only the best because thats what we have?

My volkswagen. Definitely not to be taken as rationale that I think my Volkwagen is better than my RX8 though.

 

I said interesting because two people with basically the same two cars can have such different opinions.

I never said the FD's suck or any such thing. IMO - I would rather drive my 8 than my old 7 any day on anything other than a track. It is bigger, more comfortable driving position, chassis seems better sorted out - the suspension doesn't kill me over bumps etc.... while power is power and you can't argue that - I think my TC-ed 8 is a better street car than my Single Turbo-ed FD. I would pick the FD over just about any other car I have owned or driven.... but not the 8.

Opinions are like a**holes though right?

 

exactly--its 2 different cars and 2 different people.
To the kid---I hear ya. Been there done that. Your day will come. I messed around with cheap power for yrs --hince the name--but the rotary is a challange--hell i know everything else!
OD

 

Well its not really about it being a rotary. Hell i think i have messed around one more than your average 20year old. Actually going to star a rx3 build here soon. Just waiting on shipment of car..
But The reason i don't want to mess with rx8 cause its too new and too much money. Im not into the whole cheap car, just rather not be the one doing the R&D on a new car when i don't have the funding's to do so. Its easier to buy a FD and put ### power than to do it with the Rx8.

Also any of you port and polish your TB? cause i just drove a 07 with it done and it felt way smooth. Response felt better. Deff worth to do if you know how to.

 

if you enjoy building (like me) there are a LOT of things you can do to this engine without spending a lot
examples
1- true phenolic intake gasket--you can make your own--ask me---real charge temps on this engine is outrageous--one reason oem has such rich a/f's
2- ventilate and smooth the castings inside the oem intake and intake and exhaust ports
3- port match the intake to the intake ports
4- lighten the oil pump assembly
5- seal up the exhaust port sleeves--doing away with the secondary air pump system and this way you can open up that exhaust port cooling jacket--substantially reducing exhaust port temps
6- rework the cooling jackets around the sparkplugs to decrease the "cracking " that can develop when the heat gets too high
7- get better balanced rotors installed--just have to match them up from many different ones--some machining can be done but that gets costly
8 -oil runoff coatings on inside of rotors.
9 better temp control with secondary radiator (my track temps on a 90F day in the south never over 195F--around town 180-185)
10--feather edges on the intake and exhaust ports
11- exhaust port lead edge can be widen
etc etc
point is -people are getting 260 at the flywheel on a na car. that aint to bad.
olddragger

 

So do all that to a car i still owe? thats my thing, I still owe a fair number on my car. To do all that it would take money and time. Then i dont have a car i can enjoy. And at the end i still have a car that i owe. lol im sure this car has potential, but it only worth it if you got it payed for.

 

Were you able to get the phenolic gasket on the lower intake without pulling the engine? What were the temp diffs you saw?

We need more people like you oldragger if the RX8 is truly destined to catch up to the FD's aftermarket. Hopefully, you can get around to doing all the above and report back the results!

I think you'd have to do a lot more for the Renesis though to eclipse the 13b-rew in the aftermarket performance capability dept like I think many people still think possible. Personally, I'd favor a path of modifcations aimed at safely increasing rev limit and VE at high RPM -- two-piece E-shafts, balanced rotating assembly, lightened rotors, transmission upgrade, lighter (ceramic) apex seals, and a extra peripheral intake port with SSV style valving for increased VE above 8000RPM. Our high compression ratio gives us the disadvantage that a lot of the charge compression happens without benefit of intercooling in the not-very-adiabaticly efficient combustion chamber, but we might be able to make it up with revs since we can't with boost. (13B-REW will always be better with boost) Of course, besides these mods costing major $$$, what you'd have after buildup would hardly be recognizable as a Renesis and when the RX9 owners start their forum many years from now, they'll gave RX8 owners crap for having to resort to such drastic internal engine work to make their huge whp numbers. :-)

 

So when are you going to let me have a ride in your FD, Joff?

 

She goes into pimped out mode tomorrow...... like my udgrades?

 

what is that white hose in front of the washer fluid tank ?

 

I believe thats for air pump. but i think he had said something about having something stealthy in there??

 

Oil Catch Can in old airpump housing..... NINJA!

 

lol ninja!! That is pretty cool tho, props for that. It's pretty original I've never seen anyone doing that before.

Your engine bay looks stock but your interior isn't...your gauges are pretty visible. Have you thought about hiding them?

Come on, NEWB!

 

LOL - yeah I had to strike a balance between OEM and having the car function like I needed it to!

So I figured stock looking install is as close to OEM as I can get....

 

You still did good as a sleeper. I bet you surprise the **** out of a lot of people.

Really I'm still pretty sleeper since the MS kit is pretty OEM looking just more aggressive, and most people don't see RX8's all that often so they have no idea anyways. Really only vented CF hood gives anything away. If it wasn't for that, with my hood closed no one would really know (until they hear me get on it, lol)

 

Yeah? You got one of them really loud exhausts? If you know what it sounds like you can hear mine spool... but I try to keep it on the low low.

Your intercooler will always give you away....

 

Ya my exhaust is loud. I'm used to it tho. I didn't think it was that loud, until a stock RX8 was at a stoplight next to me last week. I was like, "Oh **** my exhaust is loud!" It has a nice rotary rumble to it tho.

The intercooler will....most people won't even see it tho.

 

I made a thread about that.... LOLZ