i dont think it. it was okay before the installation. argh maybe its just me. im gonna go get that 3" doughnut and put it in. hopefully that will make the difference. but yea... my car reved very slowly yesterday night. it was weird because it seemed like it was taking forever to hit 100. i usually hit it quickly.

btw, does anyone know where i can get a 3" doughnut. i can't seem to find ANYWHERE that they sell it. i've checked midas, autozone, pepboys. anyone know where i can purcahse it?

 

The funny thing about the concern over backpressure and torque is that the effect of backpressure is directly related to the amount of overlap between the intake and exhaust cycles and the Renesis is said to have no overlap. On the other hand, a 3" system from the manifold back will typically net 10-15 h.p. on the RX-8.

 

Another way to reset the ECU is to pull the room fuse in the driver's kick fuse panel (the 15 amp fuse that is on the bottom).

Leave it out for 30 seconds. Reinstall.

If after a hundred miles you don't notice an improvement then there could be another issue with the car.

From my experience the car doesn't seem to have as much torque in the lower RPMs as when there is a cat pipe. It is also a deceptive thing because of the noise it creates having a catless midpipe a person feels the car should be going faster for the amount of noise it is producing.

In the higher RPMs there is a definite improvement with a cat delete pipe.

 

I think the need for backpressure is misunderstood. Backpressure is bad. Your motor has to actually work pumping out the exhaust gases. How is that good?? Could you imagine if your motor could get away with that pumping penalty... well it sorta can.

What you have is a situation where you have bigger piping optimized for a higher rpm window. What's happening at the low end is the enlarged pipe diameter is actually causing slower exhaust velocities compared to say when you had the smaller diameter piping on (This is also why you can't go too large either on intake manifolds). The smaller the diameter, the higher the air velocity and momentum you will attain for a given CFM, but within limits. If you can sustain high enough air velocity, it'll be like leaving a vacuum to help assist the next exhaust cycle.

The trade off for bigger piping is helps free up restriction AT a certain operating range.

 

F22, what you point out is exactly why I said that the Renesis is peculiar in that, even with almost no overlap, a well designed 3" exhaust without a cat still gains 10-15 h.p.

 

haha yea i juss gave up this idea of losing power once charles talked about the gains in the upper rpm range. i guess it'll pay off later. im not worrying about it anymore. hahah thanks guys

 

If you have a very noticeable loss of power you have lost lots of hp - maybe 30+ . There is no way the exhaust would do that (unless it is blocked) & reseting the ECU won't fix it either .

Maybe there is a blockage ???????
can you post a pic of what the donut connection looks like ?

 

Is it possible that the muffler used in this kit isn't up to the task? I would figure this problem that peter is having to be an isolated issue, however, over the last two years that I have become more and more involved in the aftermarket scene I am finding that very few people truly KNOW what the hell is going on. Mazda has no clue as to why the '04 models are having problems, the service techs are of no help, and many of the aftermarket companies are lacking in their customer service skills and technical knowledge, as well. As such, it wouldn't surprise me, at all, if the Agency system wasn't fully tested out before it was offered.

 

if it's true you should be able to swap back and notice the difference

 

well for the next week or so i am just gonna ride my car. I am going to take my car for a flywheel and clutch installation in aobut a week or two so i'll post pictures then of my doughnut.

after hearing all of you guys try to help me out, which i am very glad for, i have concluded that it is just me. i am going to dyno my car with everyone else on the 31st and check how much i am pushing. if its a good amount, then its okay. haha

but yea thanks to everyone. i guess i'll check my exhaust the day of my installation. if it is blocked or anything.

thanks again guys i'll update soon and take pics which MIGHT help you guys help me out. hahah

 

There you go again. If you think you lost power, wait until you install the flywheel.

Once again you will loose torque. Torque makes power. You will feel slower. It is slower.

The trade off is it rev's faster with the fly wheel and you can get a quicker 1/4 mile.

You will be slower in daily driving. The exhaust does the same thing. looses torque.

I'm still not convinced that a 3" exhaust will give you better results ans the engine is so small.

It seems like the the 3" setup is the way to go. I have a 3" in the back, but not up front with high flow cat yet.

Once again a too large exhaust diameter is slower. The AEM intake hasn't been proven to be superior to RB intake and is most likely slower. After adding the full 3" system you may have over done the system.

However, if you go FI or some sort of ECU upgrade you can take advantage of the the full exhaust system.

That's why a lot of people don't up grade. You get slower performance due to less torque which is less pulling power.

How often do you drive at 6k consistently during daily driving?

Everyday your slower, but if your on it you get results. Remember results are only obtained if your 6500 or more consistently in your driving.

That type of RPM will make you over the speed limit and attact attention due to the noise. It's a trade off.

Show me where you can consistently go over 6k in each gear and be legal.

 

You must be joking...

https://www.rx8club.com/showthread.p...hlight=turboxs

Our peak trq hits at 5500rpms anyways, 500rpms is not going to make a diff.

A full three inch exhaust will not drop you trq if paired with a midpipe. As a matter of fact it increases from 3000rpm on. I will admit you will not see much of a change before 3000rpms,but to say you lose trq is wrong.

 

True, that would be the best way to see if another problem exist.

 

What's worse about doing a flywheel swap while still not being sure about what is/isn't happening with the exhaust system and any power losses is that when we change more than one variable at a time we can never be sure which change is responsible for whichever outcome we are trying to analyze. Further, there are enough of us running around with 3" catless exhaust systems and light flys to tell you, unanimously, that they provide worthwhile gains across the board.

 

What planet are you on ?

 

Ya think Razz wants to test his theory by meeting me on that Forza Challenge show?

 

Ask any professional drag racer. Torque makes power. They have enough HP.

They'll take an increase in Torque over HP any day.

 

heh - only seen that once . a guy in a honda with a fake nitrous setup against a rx7 . You wouldn't do that would you charles ?

 

Ok, I'm up against Daddy Rat Fink.

And I will loose..........

It will be a fun show!

 

i'm getting a sore head now Razz

 

im getting a headache too. two sides to choose from. hahah oh well. like i said before, i am gonna trust charles cuz that guy knows a lot bout the 8(not like the others dont) but since i am looking into the same set up as he has. i will put my 8 in his hands.... hahaha

 

I looked at the photos on-line of the Agency system and I can't see anything inherently wrong in its design that would drastically differentiate it from other systems. There was one thing I did notice; the flange connector that bolts up to the factory exhaust manifold has a reduction in cross-section designed into it. If there were to be any obstruction that was obvious, that would be it. I know my Bonez midpipe has no such reduction in diameter. I also tend to prefer the single muffler design of my Borla system, but that's subjective.

 

lol i just read through this whole thing very intresting. if back presure is the issue and there is one pipe that splits in two. what would happen if you put tape over one of the mufflers. wouldnt that create more back pressure. if you get your power back then thats your problem.

ps if i just said something totaly stupid be nice "newbie"

 

ummm... Tape over an exhaust?

I will just be nice and say no, that will not help...

 

my turboXS unit came with silencers. u might try something like that and see if the car is more responsive. thatll let u know if backpressure has anything to do with it.