Somewhere an engineer is crying..

Probably the one or two that designed the intake system on the RX-8 I'm guessing.

Look at our problem this way, Mazda designed our cars to have about 250HP.

Our cars really put out (in NA trim) around 220HP.

If the car is 30HP shy of the design and something other than the intake or exhaust has been changed to loose the 30 HP changing the intake or exhaust isn't going to bring it back.

The higher the bullshit HP claim the more I despise the company making it.

That's all I have to say about that.

Vince

VINCE

MAZDA has certainly lost in the reputation stake for honesty , but they are partly owned by FORD (FOUND IN RUBBISH DUMP)

Before i buy another mazda i will be more cautious in their power output claims , they have lost their credibility imho.

michael

What's the stock intake size anyway.... 3" or just a bit more

http://rx8.swankmonkey.com/images/snorkel.jpg

And it's not that long of an intake anyway!!

edit: arrow points to emissions crap, not the intake

Originally posted by Lock & Load
Before i buy another mazda i will be more cautious in their power output claims , they have lost their credibility imho.


I don't think Vince's particular point here is Mazda - he's complaining about the vendors of aftermarket air intakes and exhausts that make ridiculous claims like 14 hp for a replacement intake (*cough*K&N*cough*).

Regards,
Gordon

OOH OK

Thanks

Originally posted by Gord96BRG
I don't think Vince's particular point here is Mazda - he's complaining about the vendors of aftermarket air intakes and exhausts that make ridiculous claims like 14 hp for a replacement intake (*cough*K&N*cough*).

Regards,
Gordon

He's talkin' Mazda all up in his post there.

Originally posted by syntrix
He's talkin' Mazda all up in his post there.

Sigh - let me translate:

Thread title: BS intake and exhaust HP claims Mazda makes no intake or exhaust HP claims. It's aftermarket vendors who make claims of improved power for their replacement components.

Somewhere an engineer is crying..

Probably the one or two that designed the intake system on the RX-8 I'm guessing.

Look at our problem this way, Mazda designed our cars to have about 250HP.

Our cars really put out (in NA trim) around 220HP.

If the car is 30HP shy of the design and something other than the intake or exhaust has been changed to loose the 30 HP changing the intake or exhaust isn't going to bring it back.

Translation: Mazda designed the stock intake and exhaust systems to easily handle engine output of 250 hp. For various emissions-related reasons, the ECU has been detuned so the engine is only putting out around 220 HP (238 claimed by Mazda). Therefore, the stock intake and exhaust are capable of supporting significantly more power than is being generated stock. The intake and exhaust systems are not the restriction on power output.

Therefore, changing the intake and exhaust systems for aftermarket components will not show any more power, especially if the ECU is unchanged.

The higher the bullshit HP claim the more I despise the company making it.

Translation: aftermarket intake/exhaust vendors claiming BS HP increases from just the installation of their components are despicable. NOT MAZDA. Aftermarket vendors.

Got it now? :)

Regards,
Gordon

Gordon,

You are so well spoken!

Vince

Well, if the ECU is making the car run very rich in open loop and you make the car breathe better, it would lean out the open loop mixture and produce more power, right?

Intakes and exhausts are really not designed for "X" amount of power, but for "Y" amount of airflow (and then noise, packaging, cost, etc. enter the equation).

I'm not saying that any aftermarket company's claim is correct or not, but there is some logic behind an improvement.

I know it's kind of like using a wrench to hammer a nail, but it does go in eventually.

;)

Originally posted by Lock & Load
VINCE

MAZDA has certainly lost in the reputation stake for honesty , but they are partly owned by FORD (FOUND IN RUBBISH DUMP)

Before i buy another mazda i will be more cautious in their power output claims , they have lost their credibility imho.

michael

FIRD?

Originally posted by O.R.A.
Well, if the ECU is making the car run very rich in open loop and you make the car breathe better, it would lean out the open loop mixture and produce more power, right?

the problem is that aftermarket replacement parts which are suppost to change the optimization of the comprimise more toward power making, don't. the problem is that the engine isn't breathing more effectively, and that "more air" isn't going in.

not to mention that the sensors the ECU uses to estimate the amount of fuel to add would simply adapt to this higher rate of ingestion appropriately, ending you up with similiarly related fuel curves anyway.

ON TOP of that, most aftermarket bullshit is built to conform to market tastes and desires, not to what actualy will perform better. take exhausts for example: no one will buy anything less than a 3" internal diameter exhaust, with no less than a 4" tip or some stupid thing on the back of their fart can muffler. does this actually help your engine breathe better?? i've got many an arguement which says no (the resonance changes with the diameter and length change, velocity isn't optimized meaning that the pressures are wrong), and heard only one voice contending it, who's still not produced any sort of theory to back up what he's said. and this "one size fits all" application nonsense is just as bad on the intake side.

"paint it pretty colours, and retard kids will buy them".

i like this thread.

Well, that's why its important that testing, be it dyno, G-Tech, whatever, be done on these products. That serves a two-fold purpose, rewarding those companies who have intelligently designed components that do what they say they'll do, and trashing those who do not.

jds

GORDON

Thanks for your clear conscise , accurate translation .

Speaking 3 languages makes life sometimes difficult , tend to think in spanish and hungarian and try and wriite in ENGLISH or should i say Australiana , and interpred in all 3 languages ,hey no wonder i get confused .

michael

No problem!

Speaking of Hungarian - Well, I can't speak it, but I do have a Hungarian dog - a Puli! :cool: Extremely cool dogs!

Regards,
Gordon

GORDON

YEAH i can just picture you with your cool dog cruising the roads , hey how can the women resist.

The puli not you , just kidding

I resently lost my boxer ( claudia to cancer ) she used to travel with me most of the time sitting upright in the passenger seat , i really miss her .

Women come and go but a good faithfull dog or car stay forever .

michael

Dynos don't lie.
If you install an intake/, exhaust or both, and you do before/after runs that verify power increase or decrease, then that is what is happening.

There are engine pumping losses through the intake and exhaust even when air/fuel ratios aren't even considered.

Rotaries respond well to intake/exhaust mods.

Well, the dynos don't lie, but they can be used in such a way as to bias the results. You don't believe the "dyno" results that you see in the commercials for products like the Tornado, do you? Just think about it, there are any number of things that you can do, like pump up the A/C in the building or running the base run while the engine isn't warmed up etc.

It might not even be a completely stock car. For an intake they could put in an exhaust with less backpressure (or not cat etc.), then by adding a intake you get even more gains than you would with just an intake. Or vice versa.

There are enough BS "dyno" results published that I'm usually skeptical unless the company has a good reputation.

Originally posted by deadrx7conv
Dynos don't lie.
If you install an intake/, exhaust or both, and you do before/after runs that verify power increase or decrease, then that is what is happening.

There are engine pumping losses through the intake and exhaust even when air/fuel ratios aren't even considered.

Rotaries respond well to intake/exhaust mods.

this is of course not what we're saying. if a real observable increase in power is evident, of course we're not going to say that it isn't... but this is the problem: we aren't observing the kinds of gains claimed by manufacturers for many reasons, all which we find reprehensible.

no mechancial process can be done with perfect efficiency. using comprimises to the effect of sound produced, fuel efficiency, drivability etc we can find more speed, but seldom do the replacement parts do this to the extent that we desire or intend (this is why the guys with the fastest cars do it themselves).

saying that rotaries respond well is of course true, as it's not entirely different from piston engines: it still ingests and exhausts itself of the same gasses, combusts them in the same manner, and transfers power the same way. they use almost universally the same hardware and "support" systems (cooling, lube, etc)... they're really not all that different, other than in fundamental archetecture.

Which aftermarket manufacturers for the RX8 have made HP claims that were proven false?

I also think that everyone assumes that an HP increase must always occur at peak. Most of the time, this is not the case. I've seen aftermarket components add 10hp without changing the peak HP. Toss in ricer math and everyone gets pissed.

And, like I said, YOU DO THE DYNO run for your own verification.

Anyone who believes any marketing/advertising dept is an idiot.

Originally posted by deadrx7conv
Anyone who believes any marketing/advertising dept is an idiot.

i think everyone agrees with this :)

Originally posted by Gord96BRG
No problem!

Speaking of Hungarian - Well, I can't speak it, but I do have a Hungarian dog - a Puli! :cool: Extremely cool dogs!
I AM Hungarian :D
(so I can speak the language of course)
Pulis are cool dogs... a good friend of mine has a "vizsla" which is also a Hungarian dog.

And, to keep this post car-related, I can't wait for my RX-8. End of October is here but the car isn't - yet... :mad:

I completely agree with his post.
The original intake is VERY well designed, flows well, pulls in fresh cold air, and is resonance tuned.

There are some HP to be gained in the exhaust.
Mainly in the midpipe, by installing one with no, or at least a less restrictive catalytic converter.

Of course these solutins involve possibly not passing emission tests in at least some jurisdictions.

Wakeech also hit an important point dead on the money:
If your ECU is controlling the flowo and fuel, then adding more airflow WILL cause it to add even more fuel at the high range of 6,000rpm and up.
The way the ECU decides how much fuel to inject is based on the readings it gets from the MAF sensor in the intake. More air WILL result in more fuel.

That is the LAST thing you need at higher rpm ranges.

As we are already WAY too rich here ( like 10:1 air fuel ratio at WOT at 6500rpm, when it should be around 12-13:1) you stand a good chance of making even less power with stock ECU AF maps.

IF you want more power, you have to:
1) Deal with the air/fuel control
2) deal with ignition advance settings
3) Open up the midpipe resistance.

I sincerley doubt any cat-back, by itself, will yield any significant amount of power, and i suspect that changing the intake will LOSE you some power.

Don't get me wrong, there is a LOT of power available in the RX-8, but it can ONLY be had with a complete solution, and touvhing the intake or exhaust by them selves will gain you jack all.

Originally posted by canzoomer
there is a LOT of power available in the RX-8, but it can ONLY be had with a complete solution, and touvhing the intake or exhaust by them selves will gain you jack all.

*wanted to highlight the most pertinant part of the post*

If you do get more air and thus more fuel, won't the ratio be the same?

100 CFM at 12:1 is going to make more power than 80 CFM at 12:1 (I am just making up the cubic feet per minute numbers)

Anyway, the biggest problem I see with aftermarket products is that it is so easy to cheat. Turn the A/C on and you lose 5HP or more right there. So as an example, they do a before run with the A/C on and they get 100hp, then put on their 2hp mod, turn the A/C off and do a test at 107hp. Wow the 2hp mod made 7hp!!

That's just an example. The dyno has to be third party.

I recommend buying a Gtech or Gtimer and do your own dyno work. If a device claims "10% more power" then at some point in the RPM band it should be making 10% more torque and thus 10% more g's. If it don't they are lying.

-Mr. Wigggles

These comments on the intkae are all very interesting to me, especially now that Rortary Extreme has just put up dyno charts of their new intake that appear to show a pretty clear increase in both torque and power across the rev range. Yes, the dyno was done by the manufacturer, however he makes a pretty good point in that why would he have waited until now to fake the dyno...he could have had the intake on the market a long time ago if he was going to do that. Sooooo...who's going to jump first and get one of these things to test independently???

jds

The dyno has to be more than third party!

Dyno's do LIE!!!!

A tech has to put in humidity and one or two other variables.

If you are in the car.. or a tech is in the car, what's to say he's not in 4th instead of 5th? What's to say the A/C is not switched on for the baseline?

What's to say that 11,001 monkeys are not near the back of the car blowing on the top of the wheels to accel faster? LOL

Is 5th better? It's probably more near 1:1 which would bypass the gears in the gearbox all together. If there's a gear difference, that could throw everything, and you would never know looking at the results!

Just trying to open your eyes a bit about dyno testing. But most manu's will do halo infested runs on a 3rd party dyno anyway ;)

-------
If it's cold here in Vegas, I could run to a shop and get a baseline.

10 mins later on a fairly warm engine, I could have 20whp without touching the car or affecting the tech's inputs on the variables!
--------

Like I said, HALO's everywhere, but it is easy to trick a dyno, and to even get varying results between HALO'd dyno runs.

I'll be the first to try a mod and put it agains LAP TIMES on a well known ROAD COURSE. That's how I judge my mods. (I will dyno for some average numbers though, but I won't rely on them until my lap times decrease!)

I can't speak for everyone else, but for me...when I said "3rd party dyno" I meant someone other than the manufacturer performing the dyno run independently, on their own, etc etc...not that the manufacturer take the stuff to a dyno they don't own.

jds

Originally posted by MrWigggles
If you do get more air and thus more fuel, won't the ratio be the same?

100 CFM at 12:1 is going to make more power than 80 CFM at 12:1 (I am just making up the cubic feet per minute numbers)

-Mr. Wigggles

Yes, but more pound of carbon result from incomplete combustion.

I have NOT done a direct comparison test, but I doubt much will be gained when the car is mistuned to start with.

OTOH, with proper tune it should gain some.

Time will tell.

Originally posted by wakeech

take exhausts for example: no one will buy anything less than a 3" internal diameter exhaust, with no less than a 4" tip or some stupid thing on the back of their fart can muffler. does this actually help your engine breathe better?? i've got many an arguement which says no (the resonance changes with the diameter and length change, velocity isn't optimized meaning that the pressures are wrong), and heard only one voice contending it, who's still not produced any sort of theory to back up what he's said. and this "one size fits all" application nonsense is just as bad on the intake side.



Alright, it’s been a while since I’ve posted, but here comes the “bigger exhaust diameter makes no difference” topic again, so maybe this will help. Everybody wants an engine that’s able to “breathe” better, but how do you quantify “breathing?” I would guess that it’s referring to having increased mass flow rate through the engine in so far as air is concerned.

So what dictates the mass flow rate? If we assume that the gas is ideal, the mass flow is a function of density, cross sectional area, and the velocity of the fluid, or Mdot=(rho)(A)(V). Assuming the density is constant in the exhaust system (just easier for flow analysis), if you increase the area, the mass flow rate increases. Forget velocities and pressures for now (both ends of the cycle are at two fixed pressures anyway), and just think of a big drum of water. Put a 2 inch line at the bottom of a 10 foot high tank and you get incredible velocity but awful flow rate. Add a 12” line in the same spot and you drain the tank MUCH faster, but at a lower velocity.

I’m still kicking around the nozzle/diffuser part of the argument (how an increased exhaust tip *might* help), but that one’s for another time.

Originally posted by Boozehound
Forget velocities and pressures for now (both ends of the cycle are at two fixed pressures anyway)

There's the major flaw in your assumptions. You're also ignoring any effect from resonance of the exhaust pulses, which have been proven many times over to be very significant. You can't just use constant flow calculations and assume that those are valid for exhaust system design.

Regards,
Gordon

Originally posted by Gord96BRG
There's the major flaw in your assumptions. You're also ignoring any effect from resonance of the exhaust pulses, which have been proven many times over to be very significant. You can't just use constant flow calculations and assume that those are valid for exhaust system design.

Regards,
Gordon

Exactly. The classic example of this are small displacement two stroke engines.

I once owned a Yamaha DT250 ( OK, a LONG time ago).
With the stock pipe it made 18HP
With an expansion chamber exhasut it made 29HP.

We have become a cynical bunch. Sure, some mfging folks have 'fibbed about their dyno claims, but others seem to have a pretty good rep. Examples are Banks Power, Holeshot Performance, and closer to home for RX8 guys, based on feedback from several folks on this forum, it would appear the boys at Rotart Extreme have been pretty straight.
My hands on experience with Dynos has been limited to 4 stroke motorcycles. I have found significant power in aftermarket exhausts (97 hp stock bike gaining 9 to 13 hp depending on the can) and some gains in power from mods to stock intake (3 hp but required a jet change) and 6 hp gains with a K N filter set up (again required a jet change). So, as Ronald Reagan always said, "Trust but verify".

Alright, if you do have to account for resonance in the system (which amounts to what? Nodal pressures that impede flow based on wave superposition?), that isn't to say that increasing your exhaust diameter won't do anything for you. You're essentially saying that pipe diameter doesn't matter in pipe flow.

Even if resonance is a huge issue (and I'm not sure there's been a good explanation of its effect on pulsed flow), you simply take that into account when designing a new exhaust system. But to simply discount nominal diameter and the effects of nozzles or diffusers on pipe flow is rediculous.