Glen, Danny, Tim, and I all had RB intake.
Top car had a CAI, final car was stock.

 

MORE food for thought: Here's the car with the K&N version 2 intake. (finished DEAD LAST)

 

as this is proof, it really is not..

you would have to do it on one car. test the change.. and still. the dyno shown does give info..

i doubt anyone here has enough testing experience to feel a 10 hp change, and a less than 5 hp change. not so much.


beers

 

The K&N has a slightly oversized MAF housing.
It causes the MAF to read low and the open-loop fueling to be lean.
That is where its power comes from.

I just spent an afternoon with one, trimming its MAF calibrations.
It is 8% off across the board.

 

I agree with swoope.
To see the diffrence; use the same car, and try both intakes.
There are a lot of other factors in the dynos...

 

-


Interesting - would the LTFT bring the fuel back in line with stock ?

 

I think Phil might had one. I'll ask him about it Sunday. Maybe he will let me use it when I Dyno on Wed.

Hey Jeff!!! is that good or bad? PM if you have to.
Thanks,
-Gil

 

he does not i talked to him already.

 

he could of had bad coils or a weak engine, i seen that most of these low dynos usually meaning beacuse the coils are on the verge of going out or engine is weak if he had a reman.

 

interesting...

 

^Dam it. I for got to ask Jeff about that post

 

hmm thats interesting ...

 

Yes, but only in the calculated load areas that equate to closed-loop - under 5500 RPM and less than .45 or so calcLoad.
After that, its open loop and the trims won't matter.

What? The Revi? It probably won't affect your dyno particularly. Its mostly meant to help cool the intake when the car is on the road.

 

I see thanks!

 

I have a couple of quick questions-

First, does the Long Term Fuel Trim carry over to Open Loop operation as Jim M. indicates on the Racing Beat web site? If it does then that 8% negative trim would most certainly lean high load operation. Perhaps clearing LTFT before each dyno run and logging data to confirm that there is no trim would remove this concern from the dyno comparison.

Second, has anyone data logged mass air flow back to back to back with all the options (plus stock) to see what increases in pumping efficiency can be had with each modification? If MAF goes up, you have more air getting in and you should be producing more power (all other things being equal).

 

From Racing Beat, "If you are interested in obtaining maximum horsepower at the extreme upper end of the RX-8 power band (i.e. racing or high performance applications), but are willing to sacrifice some level of drivability, we can make a recommendation for an alternate product from another manufacturer."
http://racingbeat.com/FRmazda4.htm (under the Revi FAQ)

Call them and ask, that alternate product is the K&N.

 

Another thing to consider, from my own experience:

When I first installed my RB intake+duct, I actually felt like I lost a little power for a while using my butt dyno. Not only that, the intake sound was kinda loud and hollow-sounding. But after like 2 weeks of driving, I (at least, believe) I felt the power increase to a little over what it was before, and the sound mellowed out. Maybe intakes need to be "broken in" a bit before you compare them?

 

Ahh it was only a matter of time.

 

if the k&n gains are from a 8% larger maf, then I consider that a false gain since the gain isn't from the intake or it's design, but rather from tricking the MAF to thinking there is less airflow and thus result with leaner AFRs.

Should you tune your car with an int-x, emu, or accessport, you'd have a leaner AFR, and be able to fine tune it properly.

 

The feel is your butt dyno.

Not much creedance there.

 

Meh works for me

 

What exactly are you expecting the difference to be between the 2 systems ? I said "even if" the difference was 5 hp, you wouldn't feel it. What do you think it is ? 10-15 hp ? Because then I would call you sadly misinformed/delusional. The poster above me said he could feel the difference between the two. I said tat is not really possible as the *** dyno isn't going to be able to tell the difference (EVEN IF IT WAS AROUND 5 hp, let alone something like 0,1.2, or 3 hp).

 

The primary issue from the K&N II is the fact that the design doesn't seal it off from the rest of the motor. If you're like me and you run without the engine cover on, you get all the hot motor air seeping into the intake...it's even worse at idle.

The RB intake duct would be useful and I've thought about installing that on my intake setup to help with IAT's while driving or in performance situations. Still, my IAT's during the summer here in AZ see upwards of 165 to 170 degrees. I have older datalogs showing it...it's insane!

I think we might be able to see true gains with the accessport once the MAF is calibrated to the intake tube size.

Actually I think that it might be off more than that as I recall the STFT trimming another 1 to 2 percent. Still, it's a good amount.

 

WHERE DO YOU GET THESE#'S???? BEACAUSE YOU ARE SADLY BEING MISINFORMED, REGARDLESS IF I GAIN HP GAIN TQ OR LOSE HP OR LOSE TQ, MY CAR OVERALL FEELS BETTER W/THE K&N RB DUCT SETUP.UNLIKE MANY OTHERS I ACTUALLY EXPERIENCED BOTH SETUPS.

 

I would love to see a blind test where you wear earmuffs and try driving your car with each of the intakes to see if you actually feel the difference, or if it's in your head due to the sound.