Intake mod for 97+ Q45

[bullittandy]

I tried a little experiment on the intake of my 99 Q45. Using some parts off my parts car I made some modifications to the intake tract by cutting off the silencer next to the driver's side valve cover and drilling several holes in the top of the airfilter box.

My goal was a better sound and overall it was moderately successful. The intake noise is more noticable but the there is no "roar," as compared to my 94 Caprice Wagon with a LT1 which sounded 10,000 times better with the intake silencers removed. There is also a slight increase in vibes which I can feel though the pedals.

Here are some pics and I plan on posting some video soon.

Does anyone have an opinion on the engineers original design and its balance of NVH? (sarcasm for you know who)

[Skibane]

Although I've never confirmed it myself, there is an old hot-rodder rule of thumb which says that ever 10 degree F. increase in air intake temperature results in a several percent* decrease in horsepower.

Cold air induction is expensive and takes up a lot of engine compartment space - and yet most manufacturers seem to think that it's worth it. For this reason, I'd be reluctant to dilute its benefit by introducing hot engine compartment air.

*I can't remember the exact number, but seem to recall it being something on the order of 2 or 3 percent.

[Q45tech]

1.00% loss per 11.0 F increase in air temperature.

[maxnix]

Might want to read TGvince's post on his solution and the assocated documentation.

Personally, I prefer 2 cards in the spokes! Vroooom! Vroooom!

Love that sucking soud!

[Q45tech]

Record and play back thru under car or engine compartment speakers any sound you want!

[bullittandy]

This summer I tried runing the car without the air "scoop" that sits on the radiator and the sound was much improved but intake air temps shot up quick when stationary and did not come once moving very quickly.

I'm just about to head out with a temp gauge mounted in the airbox to check air temps going in through the holes I drilled.

To help mitigate the hot engine bay air entering the airbox I also removed the small rubber seal under the hood that touches the radiator support.

Results to follow. . .

[qship96]

Nothing like a 13 year old 4 door sedan with child strapped in childseat rumbling and gurgling down the highway with open exhaust and modified intake....must make quite the impression pulling up to the daycare center!!!!

[bullittandy]

Prelim results are in, intake air temp just inside airbox where holes have been drilled is 12 degrees above ambient.

Will report with further results.

[Skibane]

I'd bet that the intake air temperature is quite a bit higher when your vehicle is stationary or moving slowly. In the absence of any cold air being rammed in by vehicle motion, most of the air being consumed by the engine would be drawn in through the holes in your airbox (which is the path of least resistance). Also, engine compartment temperatures are usually higher when the vehicle is stationary or moving slowly.

One way of getting some of that extra intake sound without actually ingesting hot engine compartment air would be to glue a very thin membrane (mylar?) over your air box holes, so that sound could escape without allowing air to enter.

[bullittandy]

After an extensive drive it appears that air temps are 5-12 degrees higher in airbox where I drilled holes and they rise to 15 degrees higher while stopped at a long stoplight and drop back within the lower range at abt a block travelled.

I'm going to move my temp sensor into the factory air scoop over the radiator (and cover up my drilled holes) and see how they compare.

Next move is to see if there is a hole in the fender liner that can be exploited.

[Skibane]

...preferably some place that gets LOTS of mud and water thrown off the tire...

[yodawill2000]

Can any of you Guru's tell me what looks to be two additional air intakes are on this Nissan Leopard a guy owns over in the J30 forumTotally different Intake than our J30's.I would love to have this setup on mine.

[1QIKQ45]

Did this on my G50 and the "roar" was amazingly loud!! It was a night and day differience.But i felt NO power differiences, good or bad, what-so-ever.Now if you Fabed up a true cold air, then im sure there would be SOME increases. You might not "feel" them, But at lease larger amounts of a little bit colder air would make you car breath easyer. And it wouldnt have to be working AS hard.