BMW Man

Okay... I now own a M3 & had to change my name on here because someone hacked onto my ebay account like a panzy from info that I had on this site. Whoever that is, your a deadbeat. In regards to my RX-8, I got rid of it because I was finally sick of the 36 days it had been in the shop total in 7 mos. Our local BMW dealer bought it and I got a sweet deal on a '04 Black M3 6-manual.

Anyway.......

When first inspecting the RX-8's intake system, I noticed it was pretty damn good for a stock setup, but there was room for improvement. Aftermarket Short ram's were not producing too much hp, so I decided to buy both K/N and Rotary Extreme's and give them both a shot. RE actually gained maybee 4 whp, and KN's definately lost big time hp and tq figures. People continue to argue that the stock system is the best way to go, but I disagree. Rotary Extreme, SR, or Racing Beat's are all better than stock. Maybee 3 whp, but that's still better than stock all $ aside. But something that neither of these setup's were offering was a change to the absolutely horrible location of air for the intake to suck in.
The stock RX-8's intake tube is located in a heavily concealed area behind the front bumper and along the body's frame. It is getting NO AIR and is just sucking up dead air in this confined dead space. After all the knowledge I have of air intakes with our racing shop, and the setups we had on our Viper comp. coupes, the Mclaren race car, and a little bit of common sense; I decided to chance the complete source of air.
The setup I put together is below. They are 2 air intake tubes that feed air into the intake and actually produce WHP! These pictures show my first two attempts, but I finalized my intake setup when I put both of the tubes together on the driver's side of the Rotary accent piece and it created the highest vortex of air intake. I don't have exact pics of those, becuase I don't own the car and I never took pics of it. Bascially this first example is when I tried to make it so you couldn't see the tubes, but this is only a little better than stock. The best way was to have the 2 tubes cut down from what I had so they would be shorter, and I zip-tied them in right where the bumper gets the most head-on air. Them 2 being straight created the greatest intake. But, it was here when I noticed my first problem. I was driving at full throttle when testing this on a track, so I didn't notice it at the time. While driving normal, the car literally surges every 5-10 seconds that you don't have it on full throttle; because it is getting so much air it doesn't know what to do with it. I found this fine for the track, but on the street I needed to solve it. So, I tied them into the fron honeycomb grille where less air came in and it was not as much of an increase in whp than being lower, but it was now smooth while driving.
I highly consider having two positions for the tubes if you track your car. Have them right on the front lip during track days where it gets the most air (I mean it is a huge differance); then tie them up in the honeycomb grille for daily driving (this is still a big improvement that stock).
I wish I had more pics to show you guys the final product, but I don't own the car anymore. Sorry..

The materials I used:

Roughly 10 black zip-ties
(2) 3.5" exterior diameter, 3" interior diameter, double-walled and ribbed 1,100 degree race tubing (This is what we use in our Viper's when we race in tourny's). You might be able to find these if you know anyone who works at a race shop? I don't know. I could probably give you a contact if you guys need it.
12V or 18V cordless drill
1/8" dia. drill bit

Now that I have typed my ***** off. Here are my comments...
- I put the RE intake, B&B mid-pipe, and Greddy cat-back on before I did this mod; and all those together doesn't even combine for the gain that I had with these intake tubes. This is forcing air up into the intake, the whp gain increases as you go faster (ie. the faster the speed, the more air that is being forced up into the intake).
- Make sure that you have high-temp tubing, otherwise it may catch on fire due to the high heat of the radiator, etc.
- I know this works and what gains it produced, you can either take it for what this is or never look at this post again. I don't care either way, I own a M3 now so no RX-8. I just have gotten numerous PM's asking me to post pics, and I finally have had a chance to.

Here are the pics... Now the first concept was to put them by the radiators so they weren't noticable. This woked, but was not direct air. Only a minimal gain. The second is what you can barely see in the pics; this is where I tried to tie them to the 2 post in the middle of each side of the lower intake. This was a lot better, but I still wasn't taking advantage of the full intake vortex. The third and final was then I had 2 tubes right next to eachother tied onto the Rotary accent and the lower bumper lip. Now, you could see 2 black tubes right next to each other, but the peformance gain outweighed the looks factor. This consisted of me cutting the tubes to make them directly straight on for a straight intake. This had the highest intake vortex because I had 1 big opening, instead of 2 openings that were weaker becuase they were appart. Rotary extreme said a true CAI didn't work, which I agree with; but this is basically a short-ram intake with ram-air tubes that shove air into the intake. It works better than any mod I ever put on my RX-8.


If you have any questions, pm me. Also, I don't need to read flame about this; I am doing you people a favor.

Peace,

Troy J.

BMW Man

This is a drawing of the normal driving setup... And then the track setup is second.



Track..

shelleys_man_06

Mmm. NACA ducts. How much power did you predict this supposed system would make? What about average power gains?

BMW Man

And for the stupid people, this is what the pics in the original post are of. the 1st and second concept which were both better than stock, not even close to my final track setup.



The setup that looks good (you didn't even see it), but wasn't too effective.


Bascially, the track setup looks bad with 2 tubes in front, but if you are on the track; who cares! Also, when you are driving around town you can tie them up to the grille where they are getting less air and they look good and the car drives fine because it isn't being fed too much air w/out being open throttle.

TRoy J.

JeRKy 8 Owner

Thatis awesome. Thanksfor finally posting those pics. Asfar as the tubes interfering w/the way the car looks - I think a Mazdaspeed front bumper could cure that problem b/c you probablywouldnt even be able to see the tubes unless you looked really close. Its toobad about the surging issue though

BMW Man

That surging issue is due to the fact that the car is getting just so damn much air! I am not kidding, the intake manifold & filter are directly straight on to where this air is being shot right up. If you put them in the front honeycomb grille, it will be fine. The only surging I found was when I was going 110 and the even behind the grille; tons of air was flowing it at it. The surging that I speak of is just the car wanting to go faster; it is not unsafe, but it does get annoying when the car is jerking you every 5-10 seconds.

In regards to the power. Honestly, if I were to say that the intake, midpipe, and cat-back made 9 whp; this would have to be 11-13 whp when it is in the track setup and @ full throttle all the time and 9 whp when behind the grille and not sucking in as direct of air. Remmember guys, I only had an auto, there was 1,500 rpm more or an even higher rate of air suction.

BMW Man

When you get a chance. Pop open your hood and undo the 10 or so plastic caps on the top of your bumper and look at the air intake tube. You will all see that it is sucking up air from no where except dead space that is getting no cold air.

JeRKy 8 Owner

I wonder how my stock intake would handle this.

BMW Man

When I traded in my RX-8, it had the stock intake in and it was perfectly fine. It felt less peppy than when I had my RE intake in, but it still felt good. I didn't put it back to stock, so I have no idea what increase it had over stock. I traded my car in with the tubes in the front grille.

Nemesis8

iTrader: (3)

LOL :D

I wonder what they thought?

Gord96BRG

Sorry, would you mind explaining in physics or engineering terms just what the hell a "vortex" of air intake is?

Troy, I can appreciate that common sense actually did get you a better air pickup location as you stated above - but cut the BS and techno-babble! Did you do any before/after pressure readings or temperature readings to confirm or quantify the lower air intake temperatures or higher air pressure at the filter face? Real race engineers don't just guess, they guess and measure real parameters to confirm the validity of their guesses. Real product development engineers, too.

If you really wanted to see an improvement, you should have put the stock airbox back on, and then sealed your air inlet tubes to the airbox. As it is, you didn't benefit nearly as much as you could have, because there was no seal between the hoses and the K&N filter hanging open in the engine compartment.

Regards,
Gordon

wakeech

due to funny MAF readings. read the ram air thread.

until proven (meaning stuff like scientific measurements, but bullcrap gtech dyno runs or something which can't measure a change so small) guilty of working, this mod is assumed innocent.

RobDickinson

BMW Man - lol you realy have a 'mclaren race car' come in for work? lol. Somehow I dont believe that a place that just sticks random piping to the front of an RX8 without any testing or evidence has even seen a 'mclaren race car'.

For info if you need any work doing on your Mac F1 you phone mclaren up (press the service button on the mclaren phone) and they fly someone out to you if needed. Or the cr goes to one of their dozzen or so service centers round the world. Or they dial into its ECU and see whats up.

rotarygod

While the basic idea of this system is good, and it may have in fact given him a gain, there are many problems with it's execution.

First of all, dryer duct should never ever be used in a car. The stuff is fragile and doesn't flow particularly well due to it's shape. There are many racers who use this stuff to vent their brakes. In many cases it breaks apart sending dryer duct parts into the wheel wells. Admittedly the wheel well locations are much more hostile to the ducting than this application though.

A very obvious problem with this system is the fact that the airbox is not closed in like the stock box. It is only shielded. Some people say this is enough. Let's just say I'd rather be fully enclosed in a bunker rather than a bulletproof vest when someone is shooting at me. Much of this incoming air is only going to leak out from anyplace it can and into the engine bay. The air is not being rammed into the engine. The above suggestion that ducting should be added to the existing factory setup would be far more beneficial.

The statement about the car surging from too much air to the engine can be valid. However in this context there is too little information to determine whether or not this is true. Typically when an engine is running very lean at cruising or part throttle, the car will surge. Yes this is from an abundance of air. What has failed to have been divulged is at what speeds does this happen at in this application? You are not going to get me to believe that it happened under about 100 mph (give or take a few). This also assumes that the system is completely closed in, which it isn't. It is shielded. Because of this leakage, alot of air will just bypass the intake altogether and the engine will not ingest more. There is no dead area behind the bumper. It is only a shielded area. If it were dead air where none could get into, the engine wouldn't run. It is just not ram air.

While the dual large hoses in the airstream to a sealed intake box can in fact work, it would have to be moving very fast to do so. It isn't beneficial at slow speeds. This system however I believe to be flawed in many ways. The airbox is not sealed, the dryer ducting is a substandard material which doesn't flow very well, and any claims of surging at part throttle during normal driving I do not consider to be accurate. The concept is good, but the way it was attempted was not.

BMW Man

BMW Man - lol you realy have a 'mclaren race car' come in for work? lol. Somehow I dont believe that a place that just sticks random piping to the front of an RX8 without any testing or evidence has even seen a 'mclaren race car'.

For info if you need any work doing on your Mac F1 you phone mclaren up (press the service button on the mclaren phone) and they fly someone out to you if needed. Or the cr goes to one of their dozzen or so service centers round the world. Or they dial into its ECU and see whats up.

We own a 1971 McLaren track car, it cost my dad $250k in a auction. It is a one-seater race car, NOT the Mclaren F1; my dad tried to get his hands on one but it is too expensive. If we want a fast car, we have two competition Vipers that are for the track; and our Mclaren has 800+ to the rear wheels.
I don't really care what people on here say because I was just posting this becuase people asked me to. If you don't think that this works or don't believe what I am saying, then just don't read it. We have put this on every car we have, and I will do this sooner or later for my M3. If this didn't work, then why would we have this on our cars??? 760i V12, X5 4.4 V8, soon my M3, two comp. Vipers, Busch series racing truck, 350Z.

Troy J.

BMW Man

Also, the RE intake has a heat shield that wasn't on at the time of me taking pics, becuase I had to show how the tubes entered the bumper. It was pretty much sealed up besides a little on the sides.

alnielsen

iTrader: (4)

Bruce McLaren built cars which raced in the Can-Am and USRRC series during the 60's and early 70's.

BMW Man

Ours is just like the one in the first picture, except white. I have a ton of video of my racing this car, but I don't know about pics. I will look.

Troy J.

wakeech

constructive criticism my friend. it's a good thing to listen to.

Gord96BRG

Waste of good advice! Troy has never listened to anyone here. His father has lots of money, Troy doesn't need to learn! :D

Regards,
Gordon

Gord96BRG

Good lord, you left yourself wide open for such a slam with a leading question like that. Waaaay too easy! :p

Regards,
Gordon

BMW Man

I was mearly proving a point that if it didn't work, they wouldn't be on our cars. Now, my dad's 760i's is custom done in Carbon Fiber, so it looks good; but it is bascially the same concept as mine. The setup on my RX-8 cost me about $60 in tubing and that is about it, I took the zip-ties from work.

wakeech

...that doesn't prove anything.

ok, really now. you're very enthused abotu making power and obviously have all the resources (as in the cars themselves) to do this.

in as sincere a way as i can be through the internet, i'd gladly work extensively with you on theory, design, materials, whatever you want. i have ideas and it'd be cool to see them tried out. but unfortunately in this application, your mod isn't doing what you think it's doing.

rotarygod

I wonder what the excuse is with all of the "ricer" type of products out there such as huge rear wings on front wheel drive cars, etc.

I don't doubt that there is better airflow to your intake. I do doubt very highly that it is working as a ram air system as you imply. Not with an RE intake and heat shield it isn't. If you don't have dyno proof, you don't have a basis to judge improvement. In fact even then you don't. You can't feel a few horsepower. In fact the only way to accurately judge performance from a system that relies on vehicle speed is with GPS.

I'm not saying that it isn't a good idea. Cool air is always good.

If you honestly didn't care what people think, you wouldn't have posted it. You say you are doing us a favor. You obviously care about our cars performance somewhat or you wouldn't have said anything. This isn't a new idea. Everyone and their dog has tried it on every type of car out there. Learn to take constructive criticism. You might just learn something that way. Maybe you did something good, maybe something else could be improved. You'll never know being so close minded. If anything, I am doing you a favor by pointing our how to make this work better on all of your cars. Just because you did it on a McLaren doesn't mean that it works better than on a Honda. A certain vehicle is not credibility.

I like the idea. You just used the wrong materials for it. That's not an insult. Consider it as being graded in a classroom. You get an "A" for effort but a "C" for the finished product. This doesn't mean it was a bad idea. It just means it isn't perfect and can be improved on.

Just because it works doesn't mean that it can't work better. If you truly don't care what anyone thinks, then you really don't care if it works good or not either.

RXE16T

The God has spoken. 'nuff said.