Hi guys,

came by a US site with this cold air intake

http://www.shaneracing.com/RX8_Perfo...ake_Parts.html

would any of you consider it...i mean from what you see and what is said, do you think it could be commendable, have any of you tried it??

excuse my mechanical lack of education, but if this were to be considered, would it fit in an Aussie RX8 application (being U.S and all)??

Cheers,

Daryl

 

To be perfectly honest, the stock setup is a 100% cold air intake, and the air filter is larger than a 5.7L Chev. A larger MAF tube might be beneficial, but your MAF would need to be re-calibrated.

I think it is too early to say any of these are any good.

Cheers,
Hymee.

BTW - it would fit.

 

Hmmmm, a claimed 17Kw for approx $710 plus shipping plus customs....the claim is too high IMO, the price is OTT as well.

Even the underdrive pulleys are way too dear at $USD469....

Can see no reason why it would not fit an Aust RX-8 though....

Gomez.

Edit: Just had another look at the Dyno figures.......the 17Kw is for Hi Flow Cat, Cold Air AND underdrive pulleys!!!

 

Promaz in Melbourne advise NOT to modify the standard box as its virtually perfect...He actually took the **** out of a lot of the Yank replacement units.

He replaces the stock filter element with a K&N and claims around 6-7kw increase.

 

He can claim all he likes...no way 7Kw

 

He has before/after dyno charts...

 

Sure

 

Here's a thread, there's heaps more including tests on whole K&N intakes and pod filters etc..

https://www.rx8club.com/showthread.p...k&pagenumber=1

General consensus...2hp or less. The orig paper filter is bloody huge, it has a negligible affect on air flow.

Gomez.

 

ok, so do you guys know a good store/distributor around, that has the K&N rx8 application...


Thanks

 

You are probably better off spending money elsewhere such as exhaust/suspension if you have not already done so.

Just becareful you don't over oil the K&N's as to get the MAF oily.

 

I can show you a before and after dyno chart that shows big gain and comparing "stock" to "stock".

They can be made to lie.

It is a hard world. Everyone says "Show me the dyno...", then when you do they argue about it.

I personally believe the gain shown on a replacement air filter was because the stock one was dirty.

Remember, the RX-8's element is considerably bigger than the 5.7 LS1 and they flow 300kW no worries. I know a tuner in perth and found no difference in performance between a brand new clean paper element, and a K&N style wet element. At least you can re-use the K&N. I had a KingDragon on my SS. 235rwkW unopened motor, MAF tune.

Cheers,
Hymee.

 

It would be very interesting (but not feasible) to run a car on a dyno with no air filter in a clean air environment - then we could really know what difference, if any, a freer flowing filter could theoretically make.

 

I'll talk to GTP about doing a test next time we have some time on the dyno.

 

You're better off doing some proper testing with a manometer. Mazda airboxes are ALWAYS designed well, it's just that the filter is the easiest thing to change.

Dif. Pressure testing will show you what's worth looking at and what's not. Much better than hit-and-miss mods.

 

Good advice. What rpm_pwr is saying is testing with some equipment that measured the Manifold Absolute Pressure. If the pressure there is lower than atmospheric, then there is an intake restriction. If the pressure in the inlet manifold is about the same as atmo, then there is little intake gains to be made upstream of the throttle, as the atmosphere is already pushing as much fresh charge in as possible.

Unfortunatley the RX-8 does not have an on-board MAP sensor, so an external peice of test equipment, such as the manometer, is required.

Cheers,
Hymee.

 

Exactly.

From MoTeC on the RX-8:
Unfortunately they didnt mention what the ambient pressure was, but even in the middle of a cyclone that's a low reading.

A manometer compares pressure at two points and gives you the difference. So you can move the connections around and pinpoint the exact source of the restriction. They can be much more accurate than a MAP sensor or conventional pressure gauge.

 

I would consider 95 a restriction. 100kPa is what atmosphere is, or thereabouts. It is pretty cheap and simple to get the LS1 up to 98, 99 with the stock MAF. I made my own 100mm MAF to TB tube. But the RX-8 basically has the MAF built into the equivalent tube that feeds the throttle body. It is quite well engineered. But a 4-5kPa loss could be worth chasing.

GTP already has a Motec running on a 6-port renesis. He did a 13.0s 1/4 with it, but not in an RX8, rather an 808 Wagon. He also has had to show the Motec dudes how to tune a rotary

Cheers,
Hymee.

 

Check the thread I linked earlier.....rotarygod has some experience in this area, he claims up to 4 hp, some individual RX-8's actually lose power.....

 

The problem with not running a filter, or mucking around a lot with the MAF screens is that the MAF sensor is very sensitive to air flow. Give at a trubulent airflow, and it is going to give a bad indication to the computer of how much air is going into the engine, therefore an incorrect fuel delivery. That is why some guys report bad idle when the play with things. I have seen it when we were fiddling with the RE intake on Wildcards car.

Cheers,
Hymee.

 

I know, and I'd lay money that's where Motec got those numbers and testing from

I think you're right - if it's the AFM screen there's not a hell of a lot you can do. But there is still a good chance that the restriction is elsewhere.