PontiacBonnevilleClub.com

willwren wrote:Many L36's here have used the 3.5" FWI and are very happy with it. Get someone to compare 3" to 3.5" on the same car to settle that.

My opinion? The 3" is a proven good size for the L27, and the L36 moves more air (because it revs and shifts at higher rpm's) and revs quicker (needs to develop velocity quicker) simply because it has lighter rotating internals.

You'll be better off with a gutted airbox than an ebay intake. The airbox won't pull hot air from the engine bay.

Are there any forums showing how to properly gut an airbox for a 96 bonny?

Thanks,
Bumpin'

i don't feel like searching, i can help you out with the gutting though....

Barry wrote:If so, what was the purpose of GM going from the 3" to the 3.5" throttle body inlet?

To make up for the cross sectional area that is lost from the MAF sensor.

95naSTA wrote:

Barry wrote:If so, what was the purpose of GM going from the 3" to the 3.5" throttle body inlet?

To make up for the cross sectional area that is lost from the MAF sensor.

That theory doesn't hold water. The MAF posts are essentially the same between the 3" inlet L27 TB and the 3.5" L36 TB inlet. Same basic cross-sectional area.

The L36 TB inlet OUTER diameter is 3.5" instead of the L27 3.0" because the L36 throttle plate is a larger diameter to support more flow (at the higher rpm's the L27 never sees with it's lower shift points).

In simpler terms:

GM 3800's went from a 3" TB OUTER outlet diameter to a 3.5" in 1995 with the debut of the L36 because the throttle plate changed from the 58mm L27 size to the 65mm L36 size.

That's about 2.25" in diameter for the L27 to 2.5" on the L36.

Hey I Installed the cheap ebay intake and I see exactly what you mean by useless. The filter itself got almost too hot to touch after only a short drive. It was like 92 degrees Fahrenheit outside today too so that wasn't helping the situation. I'll probably just throw the stock box back on until I can assemble a good CAI with a box and insulation.

P.S. I looked through almost all your pictures and I couldn't find any of the 96-99 style bonny with the blacked out tail lights? I saw one pic that may have been the corner of one but that was all I could find?

Forget even using that filter if you plan on shielding it.

I'll bet you that filter will hold water. Try it. APC brand? Not marked? Give us a link to your auction/seller etc or a pic you have of the intake.

willwren wrote:Forget even using that filter if you plan on shielding it.

I'll bet you that filter will hold water. Try it. APC brand? Not marked? Give us a link to your auction/seller etc or a pic you have of the intake.

http://cgi.ebay.com/ebaymotors/92-05-Po ... enameZWDVW

Let me know if that link doesn't work.

That looks like a cheesy ass spectre filter, they do hold water and they have a loose seal at the base plate. Mr.Wren is very correct about them holding water, I tested one 3 weeks ago from a friends 92 Riviera. I poured water into the filter and it took 18 seconds to drain it and 2 days in 100 degree weather to dry it out.

K definetly ripping that piece out and slapping the stock box back in for now. Ho do you gut a stock airbox?

Thanks,
Bumpin'

send pictures of your box looking into it from both sides in a pm, i'll show you want to cut out.

I had my suspicions about those filters when I found DrJay on the old Forum had one when I was in Washington at his place about 5 years ago. On a hunch, we used water to test flow, as we all know how K&N's deal with water (if you've ever cleaned one).

An hour later he had better performance and a different filter. 2 hours after that he had a heatshield. INTENSE hadn't created the FWI at that point.

We also knew alot less at that time about diameters, flow, what works, and what doesn't. Our point here is to make sure that you actually do add the performance you want, rather than lose.

willwren wrote:That theory doesn't hold water. The MAF posts are essentially the same between the 3" inlet L27 TB and the 3.5" L36 TB inlet. Same basic cross-sectional area.

The L36 TB inlet OUTER diameter is 3.5" instead of the L27 3.0" because the L36 throttle plate is a larger diameter to support more flow (at the higher rpm's the L27 never sees with it's lower shift points).

In simpler terms:

GM 3800's went from a 3" TB OUTER outlet diameter to a 3.5" in 1995 with the debut of the L36 because the throttle plate changed from the 58mm L27 size to the 65mm L36 size.

That's about 2.25" in diameter for the L27 to 2.5" on the L36.

I don't really see how that disproves my theory.
Yeah, the MAF posts are the same size in both TBs. I doubt it would have been cost effective to change that.

Mike, you stated the MAF cross-sectional area loss was the cause of the 3.5" TB. It's not. It's the throttle plate diameter increase that caused it.

willwren wrote:Mike, you stated the MAF cross-sectional area loss was the cause of the 3.5" TB. It's not. It's the throttle plate diameter increase that caused it.

Ahh. Yep I read the OP's question wrong.

You're right.

hey sorry for the delay. Here are some Mad pics of my stock air box so someone can tell me how to properly gut it.


headlight side


left side


Engine side


Engine side hole with elbow


Engine side hole without elbow


inside of headlight-side half


stock filter on engine-side half


inside of engine-side half without the filter



Thanks for any suggestions to get MORE POWER!!!!

Bumpin'

here you are.

for the headlightside, cut or yank out along the red dotted line.

for this engine side, cut/yank along the red. you might be able to do sometihng along the green side, but idk if thats the back of the box, you will have to look.


do not touch the side of the box where the elbow to the throttle body connects

You'll see little plastic tabs that hold the baffle in there, along the red dotted line. Just grind or drill them off. The baffles will come right out.

First remove this piece




This will be the result





Then start cutting the front of the Box Open




Then you'll have to remove this baffle



As you can see here the Tube is attached to the baffle, You'll now see the rear half of the Box is open...



Thats pretty much what you do to Gut the air box..

I did that about March. we also threw in a new exhaust and cat in.
well...the mechanic did the cat. he knew i wanted HP so he found something.

result.... the car has MAD pickup power. all i hear with someone else in the car with me "are we taking off for space or something?" I even keep up with my dads 745Li. (its used lol). I mean i have another friend with an SSEi and its no comparison but still one heck of an improvement. you'll like the gutted box idea. quick fix to power.

Hey I did it and Am going to install it tonight and get that crappy ebay hunk outta there! I am now thinking of wrapping the stock air box in that Reflectix stuff from menards to help with heat. What else could I do? Does any one sell any high flow air filters that fit into the stock box?

Thanks,

Bumpin'

P.S. special thanks for the guys who posted the awesome pics. they made gutting a breeze!!