10kRPMS

Well next I will test the cat less mid pipe, than my greddy ecu. I have already done some but that is for later. All the runs where on the same night. The testing was done for 6pm-7pm at night on "street night". I can tell you the car came out of the hole like crap no matter how you launch. I found myself chasing down people and passing at the end. If you look at 1/8 to 1/4 mile times You can tell the car pulls much harder out the back door. I will say though a lot of cars are not as fast as you would think they would be. Also don't think it is just the RX that has the intake issue. My friend went with me and did the same thing with his new GTI. Needless to say loss time and mph with his intake swap.

supergoat

Yea it makes me feel really good about buying just the RB duct and using a K&N drop in insead of getting the full blown REVi.

Although the REVi has more of a cool factor. :D

LiL BenNy

so basically you've raced the 1/4 a lot and pulled a 15.1 at best? im kinda disapointed in our cars...

Razz1

What I like is the last test.

A heat soaked tired engine using a Revi and it still out performed the other intakes.

Besides 1/4 mile is not where it's at. It's the handling of the car and the turns that makes the RX 8 so great.

You want to go fast? Buy a bike, can't beat a crash rocket.

yiksing

Tire heat buildup would be a factor too

swoope

iTrader: (5)

great job,

but when you pulled the vdaf you kind mucked it up....... would love to see this test done again with the rb duct, or with the vdaf still in place. with all the same intakes...

plus the stock airfilter.....

kudoos for the effort...

beers

r0tor

iTrader: (1)

15.1 launching at 4k rpms... again, looking for consistancy and not the lowest possible et's

supergoat

I doubt there was much, if any heat soak on the final run. Remember to test the REVi, it had to be installed first. The time it takes to install it is more than enough time for the engine to sufficiently cool for another pass.

10kRPMS

I want to get the RB duct and try it.

10kRPMS

You are right this car is much more fun to do this with!!!!!!!!!!!!!!!!

AvatarQAZ

I dont want to be the naysayer in all of this and am appreciative of the real world testing you are doing as well as the results.

But it was said earlier, human error is involved too much in this. There are too many variables to consider when testing this on the track. I.E.

1) Was the track temperature the same on EVERY test?
2) Did you burn the tires to the same temp everytime? Did you let the tires cool down adequately after the run?
3) Did you check tire pressure after every run to maintain consistency?

Once again, not to be a naysayer at all because the community is always welcome to more data input concerning our cars... but you need to focus on the control element of the experiment as well as mitigating potential errors in your experiment (human factor).

Jaguar_MBA

I removed my VFAD last night (I already have the aFe drop in filter) The car intake noise is louder then what it was before...and I "think" it has more get up and go in it. I mean if you can get 2HP gain from the VFAD removal, then why would someone spend ~$400 for a maybe a little bit more HP?


I know racing beat posted this:

The following table lists the measured power gains from various aftermarket components. Testing has been conducted on the Racing Beat engine dyno with both pre-production and production Renesis engines.

1. Intake – enlarging the oval inlet to the factory air box - +2 HP (this modification eliminates the VFAD intake duct.).

but this Racing Beat statement contradicts their prior statement above:

What is the purpose of the Variable Fresh Air Duct (VFAD) unit?

The Variable Fresh Air Duct (VFAD) is a vacuum operated intake valve that is incorporated into the fabric fresh air duct under the nose of the RX-8. The actual VFAD assembly is located under the nose of the car at the entrance to the stock air box. Contrary to many people's expectation, its NOT a tuning device for power – it is a tuning device for noise! Under most driving conditions (low RPM, low power) it draws intake air through the fabric duct to reduce intake noise. At 5250 RPM, the valve opens allowing some intake air to bypass the long fabric tube and reducing the pressure drop.

In our testing, using the stock air box with the VFAD operating as intended by Mazda, this assembly caused no measurable power loss. Removing it merely adds a small amount of noise below 5250 RPM.

rotarygod

You are confusing RB's statements. They said that removing the VFAD made no measurable difference from keeping it. However they said that physically enlarging the inlet to the stock airbox to give it better flow gave about 2 hp. This isn't a contradiction.

10kRPMS

I have been looking around the net and found most of the Magazines but the car in the 15.4 to 15.2 1/4 mile range. So I think I am in the right area.

Beodude123

Wouldn't it be better to do a third gear run, from about 2K through the range with a G-Tech hooked up? That way you wouldn't have human factor in there. Measure the time it takes to get from the bottom to the top. It would be fairly small, but it would give a good idea.

rotary crazy

on the rx-7 owners manual theres a test that i think is the best and that is a 40 to 65mph( dont remember the exact speed) acceleration test, it is just an accelarition test in a gear without shanging that gear from one speed to another that way theres no human error.

Jaguar_MBA

Thanks Rotary God...I was uncertain if Racing Beat "cut" the metal to enlarge the oval or not.

They never say how they enlarged the oval by or by how much. I surmise that by removing the VFAD you would in effect enlarge the oval by ~1 square inch. I say 1 square inch becuase the thichkness of the VFAD outer shell is taking up space inside the Oval inlet. If you cut that outer shell up into 1" pieces and stack them on top of each other, I believe you might be close to creating a 1" Cube.