Stock Air Box is Crap

E

esinger

Stroker Hot Air
Joined
May 28, 2004
Monday we put my buddy Pat's (SloGN) stock 84 WH1 on the dyno. It made about 145 HP and I honestly can't remember the torque numbers. He then decided to disconnect the stock airbox and make a pull. It was totally unbelieveable, the HP jumped to 185 and the torque was around 300.

Talk about a totally crappy design and one huge restriction:eek:
 
i dynoed my stock 84wh1 this past weekend. the only mod is the cat is gutted due to it coming apart and causing a no boost issue. It still has the stock exhaust.


the first pull was 144. hp 260 tq @ the rear wheels

The second pull was 185hp 300tq the only change that was made was the maf sensor and elbow was removed from the air box.

So that tells us how bad the air box assembly is. It has a paper filter in it too.


so the next this was we removed the lower half of the air box and just had the air filter and the top of the air box and the the maf sensor and elbow hooked up just like stock.

doing that netted 177 hp 292TQ. so i'm sure there will still be a gain in using a k/n filter and still leave the lower air box off. Doing that leaves about 3 inches of the filter exposed all the way around.


so i really think the 84-85 car were underrated too................


the boost was 12-13 psi.



Go get-um hot-air
 
It's amazing what just removing the intake restriction boosted the numbers. Good info and congrats.
 
the stock airbox had three design parameters it needed to meet.
1) hold an air filter of some sort
2) be quiet
3) be cheap to produce

notice that airflow capacity wasn't one of the design parameters..
 
Next time we have dyno play time, I think we should strap her on and take the intake tube off and see how much she gains from that.

Novaderrik, it simply amazes me that GM would leave so much power on the table just to choke the engine with a cheap airbox.

I think GMs got a little better over the years with their airboxes, but my 2009 G8 GT was way too silent from the factory. You wouldn't have a clue that there was a 6 liter V8 under the hood. Is the average Joe so neutered that they can't put up with some sounds of performance?
 
How similar is the 84/85 air box to the 86/87?

I have 2 stock 87 air boxes on my Chevelle, wondering if there's room for improvement.
 
It's good to see actual dyno numbers to back it up. When I first got my '84 the first thing I did was install a cold air kit, and whatta difference. I actually hit full boost quicker, did you notice that also?

So, these are RWHP numbers? That's like a 27% gain just from eliminating the stock airbox. Dang!
 
Jerryl said:
Good test.
Not trying to argue the results, just confused.
If the stock air box is good enough for 12's on an IC'd car, than the HP increase with the removal has me thinking. :confused:

http://www.turbobuick.com/forums/general-turbo-buick-tech/234280-times-thru-stock-airbox.html
Click to expand...



Jerryl

The 84-85 air box is different than a 86-87.

The snorkel is made onto the top of the air box on the 84-85 units.

But the 86-87 air boxes have a slightly longer plastic snorkel that curves slightly till is reaches the opening behind the high beam headlite


There must have been a big flow difference there cause why would have gm redone the air box?

Buick was looking to extract as much power as they could so the I/C,airbox and the intake were the first place they started.


But since jerryl don't seem to like real world data...........:eek: I'm gonna do a back to back flow test on air boxes 84-85 VS 86-87 units and see which unit flows better. i do have access to a flow bench:tongue:


Also just a tidbit of info the 84-85 air boxes are the same units that were used on the carbed turbo regals.

so they were actually meant for the 150hp turbo 6 not the 200 hp sfi 6
 
SloGN said:
Jerryl

The 84-85 air box is different than a 86-87.

The snorkel is made onto the top of the air box on the 84-85 units.

But the 86-87 air boxes have a slightly longer plastic snorkel that curves slightly till is reaches the opening behind the high beam headlite


There must have been a big flow difference there cause why would have gm redone the air box?

Buick was looking to extract as much power as they could so the I/C,airbox and the intake were the first place they started.


But since jerryl don't seem to like real world data...........:eek: I'm gonna do a back to back flow test on air boxes 84-85 VS 86-87 units and see which unit flows better. i do have access to a flow bench:tongue:


Also just a tidbit of info the 84-85 air boxes are the same units that were used on the carbed turbo regals.

so they were actually meant for the 150hp turbo 6 not the 200 hp sfi 6
Click to expand...

Actually, you got one thing wrong; I live by real world data, but do my homework on paper. :tongue:
My response was merely to further my education, that's all.
Like I said, I am not questioning your results.

I now know the difference and will be looking for an 86-87 box. :eek:
Thanks for sharing.
 
esinger said:
Next time we have dyno play time, I think we should strap her on and take the intake tube off and see how much she gains from that.

Novaderrik, it simply amazes me that GM would leave so much power on the table just to choke the engine with a cheap airbox.

I think GMs got a little better over the years with their airboxes, but my 2009 G8 GT was way too silent from the factory. You wouldn't have a clue that there was a 6 liter V8 under the hood. Is the average Joe so neutered that they can't put up with some sounds of performance?
Click to expand...

the oems have to design the cars to be below a certain decibel level as the car drives by, and intake noise is actually a big part of that.
they have come up with some weird baffle designs to try to quiet down cars over the years- that big "home plate" shaped plastic thing that sits on top of the intake manifolds of LT1 powered 94-96 B bodies (Caprice, Impala SS, etc) is actually a resonance chamber that acts to muffle the sound of air getting sucked into the engine. my 97 Cavalier had a goofy looking plastic thing stuffed up behind the driver's side fender to quiet the engine down- just taking that thing out of there actually made the car sound kind of good to me and gained me a couple of mpg.
 
kaj said:
so. what's involved in attaching an '87 box on an '85 car?
Click to expand...

There is no advantage to swapping in a 86-87 Air box. The box design is the same except for the 84-85 got the mtal snorkel and the 86-87 got the plastic one.


There is nothing more restrictive than a TR air box!.


My dyno tests prove that!
 
SloGN said:
There is no advantage to swapping in a 86-87 Air box. The box design is the same except for the 84-85 got the mtal snorkel and the 86-87 got the plastic one.


There is nothing more restrictive than a TR air box!.


My dyno tests prove that!
Click to expand...

gotcha. so go with the ol' K&N cold air intake then. works for me.
 
schody

Very curious and engrossing site, rare side on correspond to subjects so curiously worded, regularly updated and in a nice setting. And I propound checking back often.
 
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