Turbo on RX-8

[mazdamaniac]

Originally Posted by rx8man

maybe it is worth turboing a rx8???

I think so.

Its a matter of having clear goals and making correct choices.

If you are building a dyno queen or a drag car, I'd say putting a turbo on the Renesis (as it sits) is a waste of time.
If you are addicted to horsepower, the same holds true.

However, if you want a streetable screamer that you can track respectably and still put your 1.5 kids in the back and go on a road trip while embarrassing STi and Cobra owners, than a turbo Renesis is more than up to the task.

[rx8man]

Originally Posted by mazdamaniac

I think so.

Its a matter of having clear goals and making correct choices.

If you are building a dyno queen or a drag car, I'd say putting a turbo on the Renesis (as it sits) is a waste of time.
If you are addicted to horsepower, the same holds true.

However, if you want a streetable screamer that you can track respectably and still put your 1.5 kids in the back and go on a road trip while embarrassing STi and Cobra owners, than a turbo Renesis is more than up to the task.

"streetable screamer "-- is about all I'm after, having done a 20b in a rx7, -- which was heaps of fun, but once (well, what I found) you get up in the hp (kw) numbers (maybe toque?)-- then a the drive train weak(er) link will be found.
In my 20b case--2nd gearboxs and clutch were getting replaced.

But to embarrass STi (and Evo) owners I would be more than happy with

[Nutsid]

Perhaps it is just me, but I feel that newer cars aren't worth tuning. I mean, twenty years ago if a car did a 14 second quarter mile out of the box, it was damn near super car status. I don't know about any of you, but honestly, racing the STi from stop light to stop light just isn't fun to me.

I'm blessed with windy roads all around me. It is all pretty flat, but taking country roads semi quick will always be more fun than just going fast, and the Rx8 does that remarkably well.

I understand that people are always going to want to go faster, and be faster than such and such car and so and so. I just don't see the Rx8 as the car to really do it in. When I drive the car it doesn't even feel like a sports car until I really want it to be. It feels more like a regular car. It doesn't stir emotions in me that other sports cars I've owned have (I don't like FC's, but even they stir more of a sports car feel in me than the Rx8). The Rx8 just feels like it was made to be too comfortable while maintaining the sports car characteristics. A sports car like no other because it is almost the perfect blend of comfort, practicality, and a sports car.

It makes it sound like I don't like the Rx8 at all, but its quite the opposite. I love the car. It just isn't a pure sports car to me, which makes me feel like it is worthless to turbocharge, or modify to any great deal. The car is a blend of everything, and it does it perfectly well. Modifying one just takes away that balance a bit too much in my mind.

Now that goes without saying that in ten years I'd probably be more than willing to pick up another Rx8, turbocharge the bastard, and modify it like any true sports car, but that is when parts will be significantly cheaper, and the only practical rotary to modify will be an Rx8 (FB's will be like Rx3's are now, and FC's will be like FB's now, etc. etc.)

[Wangan_X]

Originally Posted by scotty305

The Lancer Evo and WRX STI include both MAP and MAF sensors. I won't pretend that I know much about how their stock ECUs work, but they are two good examples of modern turbocharged engines. It would be much cheaper to use only one sensor as opposed to two, so that makes me think that there are enough advantages and disadvantages that the OEMs would want to use both.

are you talking about the 08 models? If not I must correct you, the Evo 9 and 8 both have a MAF, which is why when they run VTA BOV's they run like poo.

[warwickben]

i bought a 05 rx8 a few weeks ago as my daily(yeah i know a daily 8 in new england isnt th best idea). my other car is a 1980 sa. i love my 8 so much even tho ive had a clutch problem with it since i got it. iam glad i sat down and read this thread. i can read this stuff all day long.

yeah i would love to get more power out of my 8, but like spock(mazdamaniac) said in a way........ most people would rather have a streetable screamer that they could drive every day then a super high hp car that they have to baby drive 90% when they have it on the road. i drive 100 miles every other weekend in rush hour traffic to hang with my friend for the weekends.i drove a buddys wrx sti up there once that was making 500 hp and id never want to do that again.

mazdamaniac i wish you could help me with the 84 mercury turbo 2.3 capri me and my buddy are building. it has a vain air meter. if you could give me tips on that ect id love you to the end of time. the whole tunning area scares the crap out of me. thats why iam a welder/ fab guy on the capri. if you could do we have to redriect the bov back in to the intake or can we vent it out with a vain. i know we could run with out and just on map but we want to have a car that the motor will last.

[rotaryextreme]

bump

[CyberPitz]

Extremely great information here....glad it got pumped!

[Nutsid]

Upon doing a lot more research on the topic, I think I would much rather do an engine swap, whether it be a 13B-REW or a 13B-RE, that would be personal preference. But you'd get a 13B much more capable of putting out gobs of horsepower, more torque, and all at around the same price as a turbo kit with aftermarket standalone system.

That would be the route I would take at least.

[rotaryextreme]

http://www.rx8club.com/showpost.php?...&postcount=346

bridgeport rx8 renny plus turbo, for you rx7 guys to take a look at.

Pretty impressive.

[Rotary Inspired]

That's with a custom made upper intake mani and a half bridged motor. I would hate to tell you what the same modifications would yeild on a older 13BT. I am over 400whp w/ stock intake manis and a 60-1 turbo. If I had all the mods he has and I wasn't over 600 on a 13BT I would be very dissapointed. Yes I have an 8 too. Great car its just not going to make the same power.

[rotaryextreme]

Well, with as much money he spent, I am 100% possitve a 13b rew would be at around 700 to 800 whp.

He said he has like 15k invested.

Still, its nice to see the renesis getting this attention.

I'm everyone is waiting to see what this infamous 16x will do when it comes out.

[Nutsid]

I'm not really a big fan of turbocharging the Renesis. I think I've made that pretty decently known in this thread already. On one hand I wish the Rx8 had more power, but on another I just wish it had less weight. The power is plenty enough to be fun stock, it just feels like it needs to go on a bit of a diet. The more I drive the car the more I get confirmation of this. Obviously this is all my opinion.

There will always be the power hungry out there, and I can understand that and appreciate that. I'm glad to see the Renesis finally putting out some decent numbers, but the cost efficiency just isn't there. I'd rather do a three rotor swap and keep it all motor with a big street port, or do a 13B-RE or REW swap into it with a big street port for the kind of money it takes to even make 350 horsepower out of the Renesis. And with any of the other three engines built like that it would be well over the 350 mark.

I just think that the Renesis is a fantastic engine naturally aspirated, and it should stay that way. Do intake, bridge it if you must, throw on some exhaust, get it tuned and you should have ample amounts of power. Get rid of the catalytic converters if you don't have emissions testing. If you want gobs of power, do an engine swap.

[Chibana]

While I can agree that compared to older rotary powered vehicles the RX-8 is heavy, this isn't a fair comparison. All modern cars are heavy. Compared to almost any other car you could compare it too, the RX-8 is lighter, sometimes by several hundred pounds. I think Mazda did a good job in keeping it's weight under control when so many other performance cars and supposed sports cars are pushing 3500 or more pounds. Hell, the new Camaro is what, 3900 lbs. with the V8? Even with the V6 it's still over 3800 lbs., I think. I'm all for a smaller, lighter 16x powered car for the next generation, but then again, I may not fit in such a car (the MX-5 was out for me for just that reason).

Having said that, I'm curious as to why the RENESIS is not as good at producing higher power numbers as older Wankels. As far as I can tell, it's the side exhaust port configuration, resulting in that 90 degree bend in the exhaust path. Are there other issues?

[Herblenny]

I like how my 8 drives.. I think turbo'd 8 does sound great.. but I'm curious how reliable it would be (as street car).

I bought a renesis motor that came out of a turbo 8 (blown motor) and it was toasted.. all 3 apex seals are gone! But the side seals were fine I'm guessing its similar to why some of us don't use high compression rotors + high boost... its bit more difficult to tune but you do gain bit of low end torque and power.

I think if I see consistent results with the set up, I might consider it. But if you add the cost involved, its still hard for me to justify. FD with BNR stage 3, upgraded IC, with 2 more 850s and it will make close to 380 in sequential set up... that's total of maybe 15-16K for the set up total (including the car).. Or buy one built for about 16K +/- 2K.

I just like how my 8 is now.. Its a good daily with back seats that I really don't use as I don't have kids and my wife hates riding in it... 90+% of time, I'm the only one driving it.. My next daily will be a G35/37.. prefer auto as I'm sick of shifting gears and want to be on the cell phone while I drive to work and home

[Nutsid]

Originally Posted by Chibana

While I can agree that compared to older rotary powered vehicles the RX-8 is heavy, this isn't a fair comparison. All modern cars are heavy. Compared to almost any other car you could compare it too, the RX-8 is lighter, sometimes by several hundred pounds. I think Mazda did a good job in keeping it's weight under control when so many other performance cars and supposed sports cars are pushing 3500 or more pounds. Hell, the new Camaro is what, 3900 lbs. with the V8? Even with the V6 it's still over 3800 lbs., I think. I'm all for a smaller, lighter 16x powered car for the next generation, but then again, I may not fit in such a car (the MX-5 was out for me for just that reason).

Having said that, I'm curious as to why the RENESIS is not as good at producing higher power numbers as older Wankels. As far as I can tell, it's the side exhaust port configuration, resulting in that 90 degree bend in the exhaust path. Are there other issues?

Oh, I agree with the weight by today's standards entirely. I actually think that a base model is really light all things considered. I'm simply stating my personal preference. I could do without my electric seat, my sunroof, my heated seats. The R3 package, for example, sounds perfect to me. Well, at least as close to perfect as you can get in a modern day car. I'm sure I'd still be longing for more weight loss, but I can understand entirely that modern day regulations prohibit the days of the FB.

And the reasoning the Renesis can't make the power older rotaries can is because of the ports. Older rotaries (ie - 13B-RE and 13B-REW) utilized large intake ports. The Renesis, albeit large, is also sacrificing port size due to its six port design (at least in the manual version), and therefore you can't have the ports as large. If you made a solid opening for the intake ports in a Renesis, however, you'd sacrifice your low end torque, and let's face it, it isn't a grand amount down there.

The six port design for a rotary only works excellent as a means to stay naturally aspirated. Four ports are what you want for a turbo application. Having said that, I am really curious as to what would happen if you ported a four port to have the same closing timing as a six port, and turbocharged it using lower compression rotors. If I had way too much money I'd test that out. If you'd notice, though, all the turbocharged rotaries that Mazda has ever produced have been four ports. Good reason for that.