Food for thought on intake setups....

[Bas]

Last saturday we finally where able to test the intake system on the Dyno. We ended the day with Mixed feelings… Did we make more hp / torque, yes we sure did (8,5 hp over a stock airbox with taitec (similar to downforce) scoop).. But the intake is far from ready! Background, we wanted a back to back comparison of various airbox types / scoop setups. We did 3 runs with every setup to make sure there where no “lucky runs”

The results:

1st run: 273 bhp (flywheel), Setup: Gruppe m air intake with stock scoop.
2nd run: 279 bhp (flywheel), Setup: Stock airbox, stock scoop.
3rd run: 281 bhp (flywheel), Setup: Stock airbox, big scoop.
4th run: 269 bhp (flywheel), Setup: R-dev intake, big scoop (This is the point where i was shockend, dissapointed etc etc. But hey thats what development is about. The only restriction we could think of was the filter.. Conclusion; remove filter.)
5th run: 287,5 bhp (flywheel), R-dev intake (without foam filter), big scoop..
We also tried putting extra fan’s around the scoop bellmouth, this had 0,0000 bhp effect…

Conclusion of the day:

1. The Honda engineers have done a pretty amazing job…
2. Every Company that sells the large scoop and claim 6 whp are talking “shit”…
3. The design we came up with “works” but only without a filter element.. So really it’s a useless result.. But we are going to work on a different filter setup.

I can hear All Nsx Owners thinking, but i can feel the differance when i mount my “big scoop” And k&n / uni filter.. This shows that “sound” makes a bigger differance then bhp’s .. Why can you be Sure the results are real and unbiased.. Well quite simple, our “own” airbox design gave a Crappy result And i’m not ashamed to honestly tell it on the web.. (I’ve invested € 3k+ in this project so yes i’m dissapointed)

Whats next? Back to the drawing board! To be continued!

Before i forget, special thanks to Gerard And Dimer van Santen and Theo Berkvens for the help! And ofcourse Pieter Oonincx at www.dp-engineering.nl for the use of his Dyno and patience between the runs when we where changing the setups.

 

[greenberet]

Thank you very much for posting that.

Is this the system you tested that made 287,5 bhp (flywheel) without a filter? That carbon intake sure looks good. Did you originally use a conical or flat foam filter and where did you position it? What were the filter's dimensions?

 

[Bas]

Thank you very much for posting that.

Is this the system you tested that made 287,5 bhp (flywheel) without a filter? That carbon intake sure looks good. Did you originally use a conical or flat foam filter and where did you position it? What were the filter's dimensions?

Yes thats the system that made 287,5 bhp, the filter position was near the TB (where the metal coupler is). We are now debating new options on filter placement and think we might have a very good option placing it furter "downstream" but i want to test it before i'm telling what i have in mind!

 

[greenberet]

I look forward to your next design and really appreciate your honesty.

Since removing the filter netted an 18.5 bhp (flywheel) gain with your first generation intake, it seems like the filter itself may be a significant restriction. To minimize the restriction the filter causes, a large surface area is good as is potentially using a filtering medium that has low restriction while still filtering the air and therefore protecting the engine well.

If it isn't too much trouble, at your next dyno day could you do one set of runs with your third setup (stock airbox, big scoop) using a stock paper air filter and one set of runs with the same setup except using a plate filter that has the same filtering medium as the R-Developments intake?

 

[RYU]

thank you for posting Bas. I'd be interested in the results of a factory airbox without the factory air filter.

 

[Bas]

Hi Regan,

The factory intake gains 1 BHP when doing a filterless run. That clearly shows that my filter position is wrong, but the shape of the intake improves the performance.
So it's back to the drawing board regarding filter placement!

Regards Bas

 

[greenberet]

2nd run: 279 bhp (flywheel), Setup: Stock airbox, stock scoop.
3rd run: 281 bhp (flywheel), Setup: Stock airbox, big scoop.

The factory intake gains 1 BHP when doing a filterless run.

4th run: 269 bhp (flywheel), Setup: R-dev intake, big scoop
5th run: 287,5 bhp (flywheel), R-dev intake (without foam filter), big scoop.

So the R-dev intake/big scoop without a filter should produce about 5 more horsepower than a stock airbox/big scoop without a filter. When you test your next design, it would be great to hold the big scoop and filter material (if any) constant and just vary the stock airbox/R-dev portion and the size, shape, and position of any filter material used. If the stock airbox design itself costs 5 bhp in a stock NSX, that's not good.

When redesigning your intake, it might be helpful to measure the pressure drop caused by various components. If you haven't seen it, there's an interesting article regarding that on autospeed.com: http://www.autospeed.com/cms/article.html?&A=0629. I've found the Dwyer Magnehelic differential pressure gauges they recommend can be bought cheaply on ebay and are really useful.

In any case, I look forward to your next series of tests!

 

[racer9x]

Looks like the highest numbers where on the 3rd run, using the stock air box with the big scoop yield an extra 2hp, over the stock scoop; you mentioned that the stock air box without the filter element increased 1HP, so I would guess that replacing the stock filter with a filter such as a UNI filter, would most likely make no difference in HP. Like others mentioned it will be interesting to see future results, I'm thinking that placing the filter element further from the throttle body will positively improve you're system.

 

[jaffaz32]

Out of curiousity did you test the Downforce Stack?

It's similar to the Gruppe M but different.

 

[TrustJDM]

Thanks for posting results of your experiment. I was curious to see why was there not a run w/the Gruppe M & a big scoop?

 

[Honcho]

I think this info just confirms what we have been saying for years- the intake restriction on a NA C30A is NOT the scoop or airbox. It is the manifold/TB itself.

 

[docjohn]

Thank you for some real robust data......this should be linked to our wiki

 

[dmscrx]

I think this info just confirms what we have been saying for years- the intake restriction on a NA C30A is NOT the scoop or airbox. It is the manifold/TB itself.

That would only be relevant if someone was considering ONLY an intake and nothing else done to the car. The DF scoop with a custom 3inch pipe connected directly to the throttle body has had the highest yield for 5 of my customers; all with other modifications done to the car. I can't say if a bigger pipe would be more beneficial or not, but if I feel like testing it later down the road I will post results here. I agree the intake manifold and TB are a big restriction for these engines, but the stock airbox is only worthwhile if the car is stock

 

[kwinkler]

Out of curiousity did you test the Downforce Stack?

It's similar to the Gruppe M but different.

These are in no way similar, other than they are both intakes. The Gruppe M is basically a ram air filter that sucks in hot air from the engine bay. The Downforce Stack is a Mugen replica that is a sealed system to the fender, which basically sucks in the cooler air from within the fender.

 

[stuntman]

It's great to see people properly testing their designs and sharing both positive and negative results during development rather than slapping something together and trying to sell it. Kudos to you!

Do you have a picture of your R-dev filter arrangement? As you alluded to, that is where your issue is and to better eliminate your filter's flow restriction it would help to see what the current design looks like.

 

[96cxt]

what size piping did you guys use?
How big was the filter (surface area wise)?