Mid pipe + exhaust
 

would this combo add any HP gains on the 8 ?

would it even pass inspection without the cat ??


--josh

guess my question is whats the best midpipe out thier? and around how much HP does it produce?

found the answer to my other question :)

B&B midpipe will produce about 5 horses.
But it isn't street legal and you might have to take it out for emission purposes.

i'm not sure on legal issue but the b&b exhaust and midpipe are suspose to give 15-18 hp gain.

I thinkthe most gain youre lookingat from those 2 mods is 5 - 7 horses -- and thats being generous. The only thing youre guaranteed is that yourcar will sound louder than stock in the high RPMs.

ahh crap, figures a midpipe would add at leat 10. these rx-8's hate mods dont they!

on vividracing.com, they say that the b&b exhaust produces 12HP and the mid pipe produces 5 HP.

I dont trustany of those companies advertised figures. Your bestbet is to read through posts on the aftermarket forum and lookfor dynos and time slips of modded Rx8s posted by othermembers. Oneguy said he got 12 - 15hp from midpipe intake and exhaust but then whenpeople asked him to post his dyno he went silent and nevermentioned it again. Overall majority state they get almost nada from those types of mods. Its sad butat least theircars sound as pretty asthey look now

well rp perfromance (rx7.com)
has a competive mid pipe for sale.
they have a sound clip and dyno sheet.
they claim to make a 22rwhp with midpipe and greddy sp exhaust.
they are a bit cheaper at rx8store.com

Here is what Racing Beat has to say about these kind of mods... I like to believe what they say because they seem to be the only one to have the Renesis on an engine dyno.

"Racing Beat is about to come out with a number of products for the new RX-8. Others have already brought products to the market with what we have found to be some rather exaggerated claims. Rather than echo these claims we prefer to report exactly and honestly the results we see. In the long run, the customer will appreciate dealing with reality, not a wish. In the past it was common to see improvements in the exhaust and intake systems of rotary engines in the 12-20 HP bracket, depending on the product. Headers in particular were a great source of power- this is no longer true. Although we are still working on a final header design, we have yet to observe more than a slight horsepower gain. Space is a limiting factor to becoming creative with a header design, and besides, the port configuration is fairly restrictive on the Renesis engine. We have found that Mazda’s exhaust manifold design is actually pretty good. Mazda has already wrung almost nearly everything they can from the engine. The are small improvements possible, but the days of the early rotaries when 10-20 horsepower gains could be realized fairly easily, those days appear to be over."

The following table lists the measured power gains from various aftermarket components. Testing has been conducted on the Racing Beat engine dyno with both pre-production and production Renesis engines.

1. Intake – enlarging the oval inlet to the factory air box - +2 HP (this modification eliminates the VFAD intake duct.) Developmental work is still being undertaken.
2. Headers – approximately 4 HP peak power gain.
3. Mufflers – muffler & connecting pipe - 2-3 HP.
4. Removing the muffler from the car (engine) – about 4 HP.
5. Remove catalytic converter and resonator from the engine completely, and replacing with "cat" replacement tube – max benefit 8 HP – regardless of what muffler is used (or even no muffler).

"The muffler "off" will yield about 4 HP, with a very loud exhaust note. With it "off" the car, the noise is unbelievable! We find 2-3 HP peak RPM maximum improvement from our exhaust, or any competitive system that we have tested. So someone can see from these numbers, it is quite difficult to get a lot more HP from this engine. The max potential with a header and race exhaust would be around 10HP."