CaR 13

does anyone have a ram air set up im trying to figure one out


88 base rx7

darkwaveboi

is it just me, or does the rx7 community not really care about cold air intakes and ram air kits..?

MaTT_FoULk

It seems that way, maybe because everyone is saving for a nice exhaust setup instead.

darkwaveboi

saving up? RX7 owners are notorious fo' bein po' (poor )

I know i am

Fatty_FC3S

The best cold air intake i have seen for an NA is the one that Checkpoint makes here in sacramento. It uses large diameter piping and mandrel bends. The filter is a real K&N and it sits in the front grille. There is a "spray shield" included to keep bugs and junk from gumming up the filter. An '89 NA put the Checkpoint Intake, Racing Beat headers, HKS catback, and Turbo 2 fuel pump on, and his car felt just like a stock '89 turbo 2. Best intake ive seen (its made like the AEM ones you see on honduhs).

Graham

pd_day

iTrader: (6)

I have a home made ram air.....
search my threads....it's a really old one...

Snufelupogus

iTrader: (2)

hehe ease troughing pd_day?

I will be making a ram air type dealy for my car. Im putting a scoop on my hood and it will flow into a box that has my cone filter in it.

darkwaveboi

hey, i read earlier about how cutting the wall between the headlight and filter was stupid.

is that true? i mean, if you cut enough of an area out to attach the filter under the stock lights, than you'd have a true cold air intake. for fREE! haha

rx-7fc

Fatty_FC3S you have any pics of the intake

bcty

i have mine under the front grill

bcty

i posted a while back with a post saying i lowered my intakes temp by half... lately when i was on a drive for an hours an a half.. its was sooo hot outside and my car ran soo cold it went back into the warm up cycle! beat that

boostmotorsport

real ram air setups make actuall posotive pressure. None of those setups are really ram airs. Efficient and worthwhile yes but not ram airs. I hate to use it for comparison but thise style intakes are all over for Civics but none are referred t as ram airs. I have read that for avery 11 degrees farenheit dropped from the intake temp you are rewarded with a 1% HP increase! Do the math!! I made a carbon fiber cold air box with a dryer duct feeding it cold air in my T2, works well, and I feel it was very worthwhile.

darkwaveboi

ahh, running TOO cold is also a problem~!

kristopher_d

Running the ENGINE too cold is more of a problem than running the INTAKE too cold. In order to increase air density enough to cause detonation, you will have to cool the intake charge well below freezing.

rx-7fc

boostmotorsport do you have any pics of your carbon fiber box

superpimp35

i actually just bid on a set of (i know z3 fenders are gay) z3 inserts, and i was going to put them into my hood......after that, i might as well make them functional by ducting them to my intake so, i also am working on a ram air type of deal....(i know get a TII hood, but i want my rx to be a little unique)

mazdaspeed7

scathcart

TII fuel pump... not so bright. The NA fuel regulator is over-run by the excess fuel and the car runs rich. Did you guys do any checking of the air/fuel ratios? I bet the car would have run faster with a good-running NA fuel pump.

I'm also always skeptical of "felt as fast" reports. I've raced cars that "felt like" 12 second cars, but actually turned out to be more like 17 second cars. If you didn't run it down the track or on the dyno, there is no valid comparison.

About december area, I am going to be making a ram air kit for my RX-7. It will attach to the stock hood scoop, and feed air to a cold air box by the air flow meter. If their is interest in a kit like this, I could manufacture one.

One of the first things I am looking into is a inlet pipe for NA RX-7's, perhaps made out of Carbon fiber. Other than airflow and cool looks, I would also include a sealable zip-up sleeve that could be filled with ice or dry ice and left prior to a drag race.

I have a few other ideas as well that I will be introducing about the december area, when production gets under way.
If their are any products you are particularly interested in seeing in being produced, I will look into having them made. Just brainstorm here.

Sean Cathcart

scathcart

Do NA cars even have a air temp sensor? I was under the impression that only TII's had them.

Regardless, I doubt that an air temp change would lower your engine temps enough to put the car back into the warm-up cycle. Even in -20 Celsius weather, after hours of driving, the cold air is not enough to cool the engine significantly enough to put the car into warm up mode.

My guess is a mechanical failure of one of your parts, either a sensor, or stuck TB plates (inducing a higher than normal idle). If not, than this I have to see, and you can show me!

Sean Cathcart

boostmotorsport

Sorry no pics of the box right now. basically if you can find any of the pics floating around of the aluminum boxes people have made, just imagine that out of CF.

Scott 89t2

I will have a VERY nice one in 1-2 months just finishing up the planing stages

but for now I'm stuck will this (no cutting!!)

NZConvertible

Yo Sean, where you been hiding?
Yes the NA's do have an air temp sensor, it's on the opposite side of the plenum to the runners, towards the rear.
There's absolutely no way a cold air intake can cause an engine to run too cold or go into it's warm-up cycle. A 100% perfect cold air intake would only be pulling in ambient temp air anyway. "Cold air" is a misleading term; "colder-than-the-engine-bay air" would be more accurate!
Ram air is another term often misused. For an intake to be truely "rammed", a decent sized scoop must face directly into the airstream, and the entire system must be sealed so that the additional pressure is contained. This means using an airbox, not a pod filter. Since I've yet to see a single car here that still uses an airbox (other than the restrictive stock one), no one here really has a ram air intake.
But a duct of at least 3" diameter pulling air from the front of the car and directing air to a pod filter cut off from the engine bay by a shield is an excellent idea, as the more ambient temp air the filter inhales, the more power the engine will make. The lower temp of the air will be detected by the air temp sensor in the airflow meter and the ECU will then calculate the higher mass of the colder air. More air mass means more fuel injected and more power.
As an example, 20degC (68degF) outside air is 9% denser than 40degC (104degF) engine bay air. That means 9% more oxygen entering the engine. You do the math...

scathcart

Just back from work. Made a bit of money for the project. How ya been?

Evil Aviator

Unlike Honduhs, the FC comes with a cold air intake from the factory.

The Checkpoint intake (see Fatty_FC3S's post) shows a ram air pressure rise when monitored by an aftermarket EMS.

Another common method is to make a system similar to that in mazdaspeed7's pics, but seal the perimeter of the radiator. The lower half of the front end is an excellent place to pick up high-pressure air.

How do you get 9%? Are you factoring in humidity?

NZConvertible

Trust you to pick that up!
No, I just found a graph on the net of air density vs. air temp that showed ~1.2kg/m³ @ 20ºC and ~1.1kg/m³ @ 40ºC; about a 9% difference. But now I’m looking at a proper psychrometric chart, just to make you happy! The above figures relate to about 20% relative humidity, witch is a bit low.
Assuming 20ºC air with 60% RH, heating this to 40ºC (typical underbonnet temp) drops density from 1.19kg/m³ to 1.11 kg/m³, a drop of 6.7%. So it’s still a significant difference.
Happy now?!