View Full Version : How easy is it to extract NA hp out of the RX8?
NECurve 12-29-2003, 12:44 AM I am in the market for a new car and have the following list:
350Z-Lots of problems, very heavy, but has great looks and good performance.
S2000-Hand built, top down fun with good performance out of the box.
EVO8-Wow...great numbers, but damn could they make it any uglier.
Now the RX8-seems like it may be a compromise of those above. Better looks than the EVO, more room than the Z and just as much fun to drive as the S. But...the performance numbers are not as good as I would like for the money. How easy is it to get more naturally aspirated power out of the RX8? and..what type of problems (major) are people having, ie. clutch, tranny etc.?
Thanks for the input!
The easiest way to gain power will be ...
1. ECU , the highly encrypted 32-bit ECU is proving hard to dechipher & will take a bit longer before a plug-n-play upgrade is available. Worth getting when they are available. Should be good for around 10-25kW
2. Intake, already quite good for a production car. Should be good for about 5kW
3. Exhaust, the secret to NA rotary performance. Extractors are a must, then a free flowing exhaust such as the (pending) Racing beat system should net you 15-25kW depending on the muffler choice.
Remember this though, the previous 13B design was good for about 225kW (330HP) as a peripheral port race engine. very angry, very noisy, very peaky (power band starts from 6000). What the max power of the 13B-MSP will turn out to be should (in theory) be less than the best from the previous types
RobDickinson 12-29-2003, 04:10 AM Canzoomer is (almost) shipping an ecu mod that gives 20-25 bhp more.
Looks like exaust/CAi will give 10bhp each ish.
From your 238bhp , without opening up the engine or FI I think you could get 280bhp at crank with the renesis.
Turbo will get ya into low 300's I think - probably not a lot more without opening up the engine.
As for problems:
Theres been a few dead engines (60?), either water in engine (seals?) or failed oil injectors which seize the engine.
Also there have been a few dead transmissions, mainly lead by Judge Ito who's managed to kill 2 so far (with 1/4mile powershift thrashing).
Thats it for major problems - and all under warrenty too.
SpYnalChRd81 12-29-2003, 04:24 AM The 350Z looked awesome the first few weeks of seeing it.
After that, seeing it every day, it makes me want to throw up...
Especially the white one that looks like a friggin bar of soap.
And the gold one that looks like a friggin bar of bronze.
I've looked at the RX-8 just about every day for six months, and it never stops looking incredible.
Get an RX-8. You never know when you're going to desperately NEED two extra seats!
flatso 12-29-2003, 08:33 AM While these type of increases sound tempting. Don't most void the warranty?
RobDickinson 12-29-2003, 08:37 AM Originally posted by flatso
While these type of increases sound tempting. Don't most void the warranty?
Yes. sort of.
Mazda would have to prove that the mod caused any problem.
So Exauhst shouldnt void warrenty, ECU updates/air intakes may (probably will).
But they couldnt refuse work on say a fuel pump if you have CAI fitted.
flatso 12-29-2003, 08:43 AM you guys that upgrade are braver men then I then
Remember this though, the previous 13B design was good for about 225kW (330HP) as a peripheral port race engine. very angry, very noisy, very peaky (power band starts from 6000). What the max power of the 13B-MSP will turn out to be should (in theory) be less than the best from the previous types
How is this? From my understanding the Renesis has some fundemental differences making it a more efficient engine then the 13b was while maintaining the same displacement. So it should be capable of superior power then the previous NA 13b.
From what I have picked up it is programmed stock to be very emissions friendly and these restrictions are hiding its true potential.
Genom 12-29-2003, 09:31 AM I've already replaced my exhaust for a slightly smoother ride and better growl. I've got my canzoomer mod on order too. After that some lower springs and it's time to make the carputer :D
I understand the warranty issues, but the exhaust and springs shouldnt be a problem for 90% of the service I might requiere, and I am prepared for anything else.
Weeeee!
FirstSpin 12-29-2003, 10:44 AM Just for reference, 225 kW is equal to 301.7 HP (not that I care, but someone might.)
flatso 12-29-2003, 10:51 AM What type of increase in torq is predicted?
neit_jnf 12-29-2003, 11:08 AM I'd suggest a drop-in high flow air filter as the stock intake system is very optimized (5hp), a complete high flow exhaust (header, straight pipe and high flow muffler) (20hp), and agressive air/fuel and ignition tuning with something like Canzoomer's Stage 2 kit or a programmable kit like e-Manage (30hp). Also, lightweight pulleys and flywheel improve throttle response and give some power because of less rotational inertia.
I believe the Renesis is capable of 300 hp at the crank in NA form without pulling the engine. Now, when the porting gets figured out it will be another story. :D
Keep in mind that rotary engines are capable of insane power levels (think over 500 hp streetable) with a correct turbo setup and porting.
NECurve 12-29-2003, 10:41 PM You guys almost have me convinced...anyone tell me if the diff/clutch can handle the extra power? What about long term reliability with Mazda, this would be the first M that I own. If it becomes my choice
vaughnc 12-30-2003, 05:19 PM The previous NA engines from 1986-1991 RX-7s lasted about 150-300+K miles depending on internal modifications, driving habits (slow=bad) , and maintenance. Even when the engines did get low on comrpession, most were DIY rebuildable which cost ~$900 for the rebuild kit and mabey $100-$250 for new motor mounts & tranny mounts.
The transmissions last practially forever, but they do need new syncros every 135K miles or so.
The clutches were built with 250BHP in mind, and since HP will increase dramatically while torque increases mildly, any external modfications shoudn't overpower the clutch.
Anyone want to confirm this with realworld experiences?
The RX-8 is built from the ground up as a street/track sports car whereas the rally type cars are still sedan based. If you want the best feel, form, & function out there with 92% of the handling/grip of the 3rd gen rx-7s, the RX-8 is the only car to get. A few springs & shock upgrades will restore the full handling of the 3rd gens as well.
Another car I've been following is the Pontiac GTO, but that's still in the Cobra class and mostly likely won't have the RX-8s "I'm on rails, ultra tight grip/handling/feel" we've all come to enjoy from Mazda as the GTO is sports sedan based. Plus is looks like a luxury car. But if you want to hall lots of stuff/kids & go fast, it's roomy :D Doubt any of the owners will race them, just take them to the dragstrip.
If you haven't already, I'd test drive the RX-8 and some of the other cars. Try to find a dealership that might be near some curvy backroads. Atlatna's Jim Ellis dealership let us abuse a test car, and I was thrilled to experience & show my passengers what the RX-8 could do with the ECU set to "limit HP due to breakin."
I personally ignore the #s and read what the Road & Track type magazines like / don't like about the feel & handling of the car. Fast numbers are just icing on the cake, but if the car doesn't have purist sports car "I love curvy roads more than quarter miles" soul, it's a sedan to me.
Also check some of the "I drove the others & bought an RX-8" post. That will give you some idea of what people do/don't like the RX-8.
Here's one, but it may be a bit biased as he's an FD owner:
http://www.rx8club.com/showthread.php?s=&threadid=17401
-=Zeqs=- 12-31-2003, 02:16 AM Originally posted by flatso
you guys that upgrade are braver men then I then
That's why I'm waiting for Mazdaspeed to bring stuff stateside. Then I'm getting the kind boys at Mazda to install them. Will cost more yes...but the warranty will stay in tact, and my ass will remain unharmed because I will not have violated my agreement with my girlfriend and step-father ;)
O.R.A. 12-31-2003, 08:13 AM Originally posted by RobDickinson
Yes. sort of.
Mazda would have to prove that the mod caused any problem.
So Exauhst shouldnt void warrenty, ECU updates/air intakes may (probably will).
But they couldnt refuse work on say a fuel pump if you have CAI fitted.
Well, they would only have to prove it if asked so in a court of law. In reality, all they need to do is claim that you are abusing the car and simply deny the warranty coverage.
93rdcurrent 12-31-2003, 01:34 PM Originally posted by -=Zeqs=-
That's why I'm waiting for Mazdaspeed to bring stuff stateside. Then I'm getting the kind boys at Mazda to install them. Will cost more yes...but the warranty will stay in tact, and my ass will remain unharmed because I will not have violated my agreement with my girlfriend and step-father ;)
Boy you too... My wife won't let me do anything that might void the warranty so I am waiting for Mazdaspeed as well ;) .
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