CAI and Mufflers?

[WS-13]

So I'm looking to squeeze a few more ponies out of my SLE. Just wanted to see what CAI and the different types of mufflers that most members are using. I would like to keep the car as quiet as possible as far as the exhaust goes. Thoughts?

[willwren]

Forget the muffler. It won't add any power until you modify your valvetrain for more flow (rockers or a cam). Want quiet, keep it stock.

Upgrade the catalytic converter to a high-flow unit for a 5-10 hp gain. A CAI will benefit you IF it's truly a COLD air intake. I suggest the FWI from www.intense-racing.com over all other options.

[00Beast]

I agree with willwren. Unless you want the sound, keep the stock mufflers.

I have the Intense FWI, and really like it. Easy to install, and good power gain.

[WS-13]

I have always had a good experience with better flowing mufflers vs OEM on my F-Bodies. It seems that they were always food for few extra ponies on the dyno. Nothing to write home about...but still. Do the factory mufflers flow that well?

[00Beast]

It's not that they flow terribly well, but the L36 doesn't flow much to need improvement. F-body is a whole different animal, a V8 needs way more flow than a V6. I'd upgrade to a high flow catalytic converter, and get a tune to get the rear O2 sensor removed (or at least the codes turned off).

[WS-13]

Is this the CAI kit that you guy's are referring to?

http://intense-racing.com/Merchant2/mer ... _Induction

[gonzo4191]

yes sir

[CMNTMXR57]

I have always had a good experience with better flowing mufflers vs OEM on my F-Bodies. It seems that they were always food for few extra ponies on the dyno. Nothing to write home about...but still. Do the factory mufflers flow that well?

The difference is, the exhaust layout and the one massive muffler (which is very restrictive on a stock layout) for an F-Body stinks monkey poopoo! SO when you replace it with any of the aftermarkt options, it really uncorks the system. It usually leaves the drivers side as the primary outlet being a free for all pass through, and the passenger side just picks up what is left over from the perforations in the tubing inside the muffler. Couple that uncorking with an engine that loves to flow air through it's heads as RPM's build, and that's why your LS1 had soo much gain.

Whereas, the stock layout on a Bonneville is pretty straight, the mufflers aren't bad, but not really performance minded. SO there isn't as much initial restriction. No matter what many here say, the OEM mufflers are a balance of sound, performance, and durability. They have to be or GM couldn't sell it that way. Hence there is still room for improvement from a performance perspective. But yes, it is mostly sound quality that you'll affect by changing them and you probably won't notice much in the butt-o-meter by changing them out.

[willwren]

The L67 actually outflows the F-body 8. But our exhaust is much less restrictive.

[WS-13]

I'm going to test this theory soon. I'm going to to a dyno pull before I replace the muffler, and after. Like I said before...I'm not nor am I expecting huge gains. Even on an F-body, the gains are minimal at best. I'm just looking for a little more hp and gas mileage improvement to make the the car more efficient.

[00Beast]

Unless you throw in a larger, high flow cat, the muffler isn't going to be the restriction. I'd add a 2.5 or 3" Downpipe and HF cat before I would change my mufflers.

[01bonneSC]

I'm going to test this theory soon. I'm going to to a dyno pull before I replace the muffler, and after. Like I said before...I'm not nor am I expecting huge gains. Even on an F-body, the gains are minimal at best. I'm just looking for a little more hp and gas mileage improvement to make the the car more efficient.

Throw higher ratio rockers on...

[WS-13]

I'm going to test this theory soon. I'm going to to a dyno pull before I replace the muffler, and after. Like I said before...I'm not nor am I expecting huge gains. Even on an F-body, the gains are minimal at best. I'm just looking for a little more hp and gas mileage improvement to make the the car more efficient.

Throw higher ratio rockers on...

I was think about this, and possibly a cam and spring swap. I'm going to pull the intake manifold anyway to replace the gaskets.

[01bonneSC]

If you are gonna do a cam, dont do the rockers then. Gets iffy with piston to valve clearance on these engines.

[00Beast]

Or if you do rockers, go with 1.6's. They help cut down on valvetrain friction. If they free up 5HP, that's about it, though.

[01bonneSC]

Or if you do rockers, go with 1.6's. They help cut down on valvetrain friction. If they free up 5HP, that's about it, though.

Thats the ratio stock right? Just for my own knowledge

[00Beast]

Or if you do rockers, go with 1.6's. They help cut down on valvetrain friction. If they free up 5HP, that's about it, though.

Thats the ratio stock right? Just for my own knowledge

Yeah, stock ratio is 1.6. Upgrading to roller rockers is just for lower valvetrain mass and friction.

[01bonneSC]

Or if you do rockers, go with 1.6's. They help cut down on valvetrain friction. If they free up 5HP, that's about it, though.

Thats the ratio stock right? Just for my own knowledge

Yeah, stock ratio is 1.6. Upgrading to roller rockers is just for lower valvetrain mass and friction.

Thanks! and yuppers!