ccw998

Hi,
Today when I show my M2 air box to a mechanic (he doesn't know much about FD), he said that M2 is a cold air intake box, but it is difficult to get outside air into the box. He said that I need to make a custom hose connect from the front bumber to the M2 box. Is it ture? Any suggestion?

Thanks!!

Johnsrx7

Did you take the foam from the side of the radiator out? If so, it gets a ton of air and a lot more than stock. I would not listen to your mechanic here.

matty

see..i think some sort of duct would help

ZeroBanger

If you dont have an R1 you can put a ram air from where the oil cooler would be. Also, you can do it from under the car inbetween the radiator and the chassis. Thats how I did mine.

The cost is minimal and its not noticable unless your looking for it. I picked up 5 MPH on my trap speed from this, but I warn you that you need to clean your filters often. My box is the rx7fashion box, but its the same.

The ram air that is in the nose of the car (between radiator and chassis) is done by using an old stock IC hose.

The other one is more complex, it involves a 8 X 9 X 4 plastic container that fits exactly over where the oil cooler would be if it was an R1 (you have to remove the black plastic piece). I bought it at home depot and it has a 3 inch round opening at the top. I think this piece was designed for gutters or something, Anyway from there I bought 3 inch vaccuum cleaner hose (the cooregated hose) and routed it from that location, throught the plastic undercarriage and into the bottom of the air box. the ram air from under the car goes to my primary turbo, the other ram air goes to my secondary turbo.

ptrhahn

iTrader: (9)

Anything might *help*, but i would figure figure that if the surface area size of the opening is any larger that the area of the two openings in the 2.5" intake pipes, it really won't help anything... assuming that opening is getting a clean shot of air...

rynberg

Zerobanger has proved in drag strip testing that the cold air boxes do NOT flow as much air as a modified stock box. His trap speed was consistently lower by 2-3 mph after he installed his CAI box. Once he re-ran a duct from the front of the car to the intake (same set-up as his modified stock box), his trap speed went back up to where it was.

ccw998: You will definitely notice a difference running a duct to the front of the car.

This is just more evidence that a modified stock box is as good as you can get for air flow/temps. It's too bad you have to ditch it to run a larger IC.

EDIT: Geez, I don't type fast enough.

ZeroBanger

I did substantial testing last year at the drag strip. I ran about 60 1/4 mile runs last season. During these tests I compared my trap speed with

Stock box
stock box with ram air through bottom

rx7fashion box
rxyfashion box with ram air

I found that the M2/Rx7fashion box were no more effective than the stock box until you rammed air into it. In the end I gained about 5 MPH on my trap speed with the ram air into the rx7fashion box than without. I also found that the m2/rx7fashion box was a better box to ram air into due to the filters and the fact that the box is smaller and cant more air to the turbos quicker (assuming you ram air).

You also need to seal the bottom of the box to keep the radiator air from getting into it.

ZeroBanger

ROTFLMFAO....

Thats funny! Yea Tyler, I think that once the stock box and the rx7fashion/m2 boxes have ram air, that the rx7fashion/m2 box are better. But without ram/air both boxes are equivelant.

The fact is, look at the design of the rx7fashion/m2 box. air doesn't ram into the box unless you force it with a tube. The fact is the front bumper is in the way of the air flow and if you have fog lights its even worse. Its not the fault of the boxes, its just they had to build around mazda's unique engineering.

BTW..if you look at my threads from last year, I had exhaust, ecu and bolt ons with a STOCK air box that was modified with a ram air. I then got a midpipe, injectors, fuel pump and rx7fashion box. I went to the drag strip and my trap was a few MPH LESS than it was with my highflow cat!!!! I rammed air into my rx7fashion intake and my trap went from 105 to 110.

ccw998

Thanks for the information. Where can I get the duct or ram? Any picture for them?

Thanks!!

Mahjik

iTrader: (1)

Check this thread:

https://www.rx7club.com/forum/showth...hreadid=162205

ZeroBanger

i'll try to get a basic picture, but in the end you have to engineer it yourself, there are *MANY* ways to do this.

That damanB or damian (you know the genious) he did something simlar with dryer ducting. search on his name and you may see his idea, he has lots of pics. I used the hard plastic hose, cause it cant get damaged/dented.

Airflow is the name of the game we play, dont forget it.

ZeroBanger

I must be reading everyones mind today. Ok, Im done. Good luck!

ptrhahn

iTrader: (9)

I don't see how that ducting would be posssible with dual oil coolers.

ZeroBanger

you can still duct the car underneath between the radiator and the chassis. You will be drawing air in from the nose. If you have factory fog lights its more difficult, though.

ptrhahn

iTrader: (9)

But it already draws air from between the radiator and chassis w/ an aftermarket box.... it would likely be high pressure as well since they even determined air was actually spilling BACK out the nose opening w/ the '99 nose...

ZeroBanger

Actually no. I have done enough research to realize whats happening. Next time you see a M2 or Rx7fashion air box take a look at the opening of the box under the car. The bumper of the car is parallel to the opening, which blocks the air. You get very little air.

My tests dont lie. Im not talking about 1 or 2 drag strip runs, I'm talking about 60 or so. Test after test after test came to the same conclusion.

Also the rx7fashion intake has a hole to the left of it to relieve any excess air that gets into the intake. Hope this helps.

BTW...Anyone that doesn't believe me can go to pepboys or target and for 7.50 get a digital thermo probe that has a temp relay with a cord and a digital display and put it in your intake box. Do it with ram air and without and see the difference in the air temps.

darkside7

iTrader: (12)

i don't know about getting more air, but what i'm doing is cutting out a vent on top of the M2 box which sits right bellow my vented hood. i think this should help move more air, and help prevent air in the box from being stagnet and heating up.

ptrhahn

iTrader: (9)

IF you could add a ram air source independent of the nose opening (like with the oil cooler opening) i would agree that it would help (i actually have this rigged up right now, though the hose only points AT the opening beside the rad), but without the use of that opening, i havent SEEN any rigged up ducting strategy that wouldn't block more air then it feeds... believe me i've looked.

Also, any air that enters the nose will naturally flow to the path of least resistance (which i'm certain is a gap beside the radiator with SUCKING intake filters behind it, rather than a dense radiator)... thats why if you don't fill the gap on the other side, you won't get maximum cooling... air finds the holes....

i don't doubt your results, just that i havent seen anything effective other than using the OC opening, and i won't have that option in another week :-)

adam c

iTrader: (2)

Zerobanger is right about the ram air effect. There is definitely some power to be gained. The downside is that you get a lot more than air coming in that ram funnel. It can suck up bugs, water, leaves, rocks, and just about anything else that the front of the car encounters.

If you remove the foam next to the radiator, a lot of cool air will come in. In addition, the intakes will pull cool air from under the car. You can still get pretty good airflow with out the funnel.

It's a trade off. If you want a little more power with the ram effect, you are going to clean/replace your filters more often. If you have a stock airbox, you can do my "Cheap Bastard" intake mod, and get the same performance as the M2/Fashion boxes.

ptrhahn

iTrader: (9)

As a comparison, the PFS intake basically mimicks what you are doing (at the expense of the intercooler), by shooting a 3" hose at the intake box from a ram air (IC) duct. I cut the bottom out of it and added sheilding to mimick the M2/CWR boxes... and it did help considerably.. so i'm not doubting the theory...

i just don't know how you would do that in reverse w/ the M2/CWR boxes if you can't source from the oil cooler duct.

ZeroBanger

FYI,

My ram air tests were done with the hose drawing air from the nose of the car. I got my highest trap speed (110) in the 1 test that I did that had BOTH ram air intakes. In otherwords, I got about 3 MPH from the lower ram air and about 2 MPH more when I added the 2nd ram air. I didn't get to follow up with more tests yet, but I can say that the MAJORITY of my tests were with the ram air from the nose of my car and yes it does add alot of power, it channels the air INTO the intake, something the M2/Rx7fashion boxes DONT do.

ptrhahn

iTrader: (9)

Got any pics of the duct from the nose of the car (NOT the one from the oil cooler)?

Like i say, i have yet to SEE any feasable duct like this... i'm not willing to just stuff dryer hose into the gaps... too ghetto for me, and won't hold up if i have a mechanic work on the car....

I was never debating that more ducting to the intake wouldn't help... just how you'd get there...

adam c

iTrader: (2)

Maxpesce has a funnel from the nose of the car to supply additional air. He has some pics somewhere on this site. Wish I knew how to find them.

ZeroBanger

I have an IC duct hose, the part that is attached to the lower part of the intake is squeezed, so it forms an oblong shape into the bottom of the intake. This is because there is not much room between the radiator and the chassis to put the hose.

Actually now that I think about it, you should try to find my old thread..its something like "Interesting trap speed experiment" or so. I would guess its from last october. I remember another way i tested this. Try this for yourself. Take an IC hose (3.5-4 inches) and squeeze it between the radiator and the chassis and reach down in the intake box with a pair of plyers and pull the hose till its sealed inside the intake box. stick a fan infront of the nose of the car and turn it on high. put your hand in the intake box and feel the flow of air. Then take out the ram air and do it again. ITS AN AMAZING DIFFERENCE.

Now, I realize that everyone has views and opinions and I respect that. We are all hear to learn and I have done some research so i'm just sharing. But try my example above. You can even use a hair dryer, but a fan is a better example since its stationary.