Rotorain

Hello, I am new to this forum, so bear with me if this is in the wrong place. I recently bought a 2004 RX8 GT MT with 150k miles on the motor. It still runs great and feels like I'll be able to get at least another 5k out of it treating it like a baby, but I am buying a new motor (hopefully 0 or very low miles) so that when my current one dies, I will have a replacement lined up. I am looking to make about 300 whp N/A in the short run, and about 400 whp (probably boosted) at some point in the future. Because I am getting the motor hopefully before my current one dies, I want to modify it while I have it outside the car, so it will be relatively easy to do almost anything to it.

For everyone who has modified your RX8 for power gains, what would you do with a brand new motor outside the car before you swap it in?

I already have a racing beat exhaust, K&N typhoon intake, lightened flywheel, and an upgraded clutch (not sure which one, but it feels like a street disc). Based on some basic research, I am thinking about porting, injectors, upgraded apex seals, and an accessport, but if you think other mods would be better, i'll gladly take any advice!

nycgps

iTrader: (1)

*sigh*

*facepalm*

Rotorain

Like I said, I am completely new to this. If you would like to point me in a direction more specific than the search bar, I'd appreciate it.

HiFlite999

iTrader: (2)

300 hp na? Buy a Mustang.

Read the stickies at the top of each forum section.

https://www.rx8club.com/rx-8-discuss...rx-8-a-233937/

Rotorain

So the general point of that article is that in order to make any significant power gains, I have to boost it. So I guess I'm going to have to take it in the 'maximum reliability' direction so that a future turbocharger doesn't blow the engine apart within a few miles. Apex seals, coolant channels, and an accessport?

bse50

Search, there are approximately 900 threads like yours already.

To make 300rwhp NA you have to ditch the side exhaust ports. That's expensive.
To make a reliable boosted 400rwhp you have to ditch the whole engine and put on a rew. That's expensive.

HexRX

I would imagine that inorder to make 300rwhp NA you are going to have to port the hell out of the engine, IIRC heavy porting on the 13B-MSP was not recommended as it did something involving the cooling passages :/

bse50

To achieve 300rwhp NA out of a renesis you have to throw away everything that makes it a renesis. Except the high compression rotors

TeamRX8

iTrader: (25)

you will have better luck showing up at the Tour de France on a Walmart bike ...

patrick_andraste

RB26

Jake33

iTrader: (2)

ok. that engine bay looks like a nightmare.

Lvis

ditch your spare and get a fd swap

chepetech

iTrader: (2)

Get a honda civic...vtec puts out 300whp. Lol

Good luck buddy,there really isn't anything you can really do with the renesis being na.

Lvis

youll be surprised how many street drivin na k series are putting 300plus whp.
I think someone is starting to get very disappointed about buying a car with such high expectations. Like i said for good reliable power an fd swap will be your best bet

nycgps

iTrader: (1)

13B should have ended at REW.

and comparing 13B-MSP to previous 13B series is just not an apple to apple comparison, All previous rotary engines before MSP were designed for power. MSP is strictly for emission purposes. and 13B's origin is not even designed for this purposes.

the next one will design for power and emission. you can tell by looking at the early 16x engine design.

wcs

iTrader: (2)

Like wth guys??

Rotorain

Actually a good friend of mine has a civic si with a boosted k24 that puts out 300hp and like 280 lb/ft of torque, while getting 20-25 mpg. Looking at it now, the rx8 is never really going to beat that in a straight line...

Lvis

rx8's are NOT made for straight line speed, there a great track car not a drag strip car. The 8 goes fast on turns, u cant compare it to a civic its to totally different animals

Rotorain

I completely agree with you. The cornering feel is the reason I have an rx8. I could go faster for less money, but nothing really drives like the 8. I am halfway through putting a brand new motor in mine right now.
I have an efi small block El Camino for going fast in a straight line, but it's the feel of the 8 that's worth more than the numbers on paper ya know?

patrick_andraste

Build the Elky. How much power do you want?
before it got worn out by teenagers... It would pull on most anything from 60 mph to 120 mph. Below 60 it would just go sideways unless you had a good launch.

Beodude

iTrader: (3)

What the heck are you talking about? Yes, the MSP was designed with emissions and fuel range in mind, but it's still the most powerful NA 13b in a stock car. Emissions hardly even mattered in the 80s, so you don't really have much ground to stand on. If Mazda hadn't designed the MSP to be as efficient and power producing as possible, why is it that we have all posted "dude, power adders do nothing for an NA car" on every new thread that people ask for advice.

If anything, I'd say that it was designed more for power than anything else. The entire S-DAIS is designed to maximize power across the rev range. Otherwise the Renesis would have a more peaky torque curve, instead of the torque table we have. Think about all the weight they shaved, all the engineering they put into the car. Everything is meant to be light weight but safe, stiff, yet refined... I know I'm preaching to the quire, but still. The intake ports wouldn't have been 50% larger if they weren't going for power.

For what it is, the MSP is a pretty decent engine. Certainly not the best, but it's good at what it does. I think people just have carried too much expectation into getting one, and really miss out on the point.