can anyone tell me how to mod a stock air box on a stock c5. i have heard that the mod can pick up some hp.

 

There's several ways to do it. Which one? You can get more air and air intake noise, but appreciable horsepower/torque improvements may be hard to determine w/o base and dyno testing.

The sound of an increase of incoming air is what most equate to more horsepower. The computer can make minor adjustments to compensate for the change.

In C5 Tech, use search or search this forum (in the red banner). Use keywords "zip tie" or "flip tie".

Some prefer to use the top cover from a Z06 to allow in more air. The oem C5 coupe/convertible top cover didn't have an opening on the top cover as did the Z06.

I modified the top cover of my Z06/Z16 in this manner. Yes, I know...it's a very rare 110v model...

 

The mod done by Hotwheels57 is by far one of the nicest jobs I've seen. I just took a dremel and opened up several slots between the stiffening ribs to let more air in. No screen, but mine is a track car that won't see much debri other than marbles.

 

You could always do what I did.


http://forums.corvetteforum.com/c5-t...ing-loose.html

 

Very nice...but I would have went with 220v or 221...whatever it takes.

 

I'm sure he could have but he would have needed a built bottom end for that much power.

 

I did what hotwheels57 did...except way less nice I am not so sure it did much but I doubt it hurts

 

A fun thing to do,but you really wont notice any slight Hp gains you may get.

 

GMPT Assistant Chief Engineer for GEN 3 Engines John Juriga made a statement that I'll paraphrase here as a comparrison of the '01 LS6 and '02 LS6.
' swapping the '02 redesigned fresh air box ( just the top's opening is different) and removing the MAF straightener screen was worth approx. 10 hp to the '01 LS6'.

In another '01 LS6 performance article just removing the straightener screen from the MAF was worth 5 hp ('02-'04 LS6 have no MAF screen) as the air flow with the Z06 ducting was sufficiently 'straight' forthe MAF to monitor accurately.

So deductions conclude that some improvement is theoretically possible . Even a grader degree if swapping a '02-'04 Z06 fresh air box , bridge , ducting ect allowing the removal of the MAF screen. This is of course an old trick going back to the mid '80s. The trick is to get the fresh intake air to pass straight thru the MAF.


hotwheel57, nice work on that filter top !

 

Thanks! The only issue I've experienced so far is finding long enough extension cords...

 

nice work 'wheels...
Bill

 

I have watched/read many mods for the C5 Vette air intake system. Mine is different. I have a 2000 base model vert. I don't have a small triangular hole anywhere on my airbox (top or bottom). I have 2 tubes on each side that are molded into the top of the filter cover where the metal straps go that follow the curvature of the top cover and face down. Does anyone else have this type? I read about adding the front gasket for the hood but see no reason with the way my airbox is made. Had I thought I would have taken a pic as an example.

 

Go to "YouTube" and in the search box write.....C5 Corvette zip tie MOD. Its about six minutes and it will explain what it should look like and why it works.

 

I have watched it and don't like the chance of water entering the system. My stock airbox is fine with me and I see no reason to mod it. I mainly wanted to see if anyone else has this airbox cover because I have not seen one in any post I have read.

 

Here is the other side of the story, when they were working on the Z06 engine in the late 90's they started with the 01 cam profile and had completed all the verification testing on that engine. When Heinracy was testing the engine he wanted more mid level and upper horsepower so the developed the 02-04 cam profile. However the complete verification process was not complete in time for the 01's. When the testing was being done on the air intake, MAF, TB, etc the did run tests on the larger and original items. However all the testing was done with the Z06 software and firmware packages and not the stock C5 software. The 02+ MAF were the same size but the standard C5 software would not work well with the unscreened MAF and GM did not want to run all the verification testing for little or no gain. The Z06 gained more HP in the upper RPM range so they needed a little more air to optimize it, hence the larger opening in the air box. In the early C5 SCCA days they were able to get an air cleaner modification for the Donaldson air cleaner. Not because it made more power, but the wheel to wheel racing often created a lot of road dust and it was an excellent air filter. You can add all the air you want to your engine but it still has to go thru the MAF to the TB and a 5.7L engine which has about 43.25 cubic inches of displacement per cylinder, so unless you are turbo or supercharging the engine you will not add in more air. The Vera Ram is a good air cleaner system and its ram effect on the C5 corvette is about 3/4 hp at 75 mph and almost 4 HP at 150.

Your engine PCM has about 512K of data, 96 of it is programmable and the remainder is firmware that cannot be changed, unless by GM

 

Way old thread...but I'm not uptight if the info is topical.

Sounds like you have the early design...'97-'00 IIRC.





Later air boxes ('01-'04 IIRC) looked like this:




And the LS6 (Z06) air boxes looked like this:




Not sure if the lids are interchangeable from old design to new, but it looks like they could be. Either way, the complete airbox should be interchangeable. If you're not into aftermarket CAI's, or modifying the OEM...you could always swap in an LS6 airbox, if you can find one reasonably priced.

 

yep thats the one I have, the early airbox. I don't know if it's better/worse than the other versions but it's good enough for me.

Thanks for the pics and info.