I've a C5 Convertible 6 spd, with the standard LS1 engine and in process of deciding whether to uprgrade with cold air intake and American Racing Headers ( #C5-04178300LSWC); my concern is how severe the noise increase will be inside ? Can someone offer an opinion?

 

Save you money on the cai. A stock z06 air box flows about 1100 cfm with a paper filter.

Headers will be louder in the cockpit and at the exhaust tip, but a lower tone. Plus they throw a lot more heat. If you go with them consider a thicker tunnel plate and DEI tunnel insulation kit.

I had a 2003 vert. Installed 3.90 gears, a Z06 air box lid, and had a dyno tune. Ran like a bat out of hell. The gears transform the acceleration. Never considered engine mods after that…

 

I have headers w/ a z06 cat back. Interior noise is not much worse than stock, like vette4fl said, just a lower frequency noise.
I hear my supercharger much more than the exhaust.

 

Thank You. I'll probably show my ignorance here, but what do you mean by 'cat back'? Have had one other reply warning me to think about the extra heat from the headers. I know yours is a Z06 but Did you notice a difference?

Sorry, this REPLY was meant for JMG2

 

vette4fl - Thank You. I'll take your points into my decision process. I think I Should have added some other info for you tho. Along with the Airaid SyntaMax MXP CAI, the shop is suggesting an AEM Air/Fuel sensor. Also, about 5 years ago, a buddy put a K&N air inlet kit, and new valve lifters ( cant remember/find the spec., but they just hold the valve open very slightly longer,) and He tried to put a different mass flow sensor too but could never get it to stop kicking error codes so took it off.

 

There are a couple different terms and systems used. Cat back generally refers to the part of the exhaust after the catalytic converters. Borla, FlowMaster, and a few other companies offer a cat back "X" pipe to replace the inefficient "H" stock pipe. You might also consider an "axle back" system, which is replacing the exhaust at the flange connection just ahead of the rear axle.
Really, unless you're racing, most systems are just for sound.

 

Welcome to the forum! I agree that the cold air intake is more trouble than it's worth. Headers are a great mod though. when the shop does the headers, they will almost certainly do an x-pipe with them. The cat back or axel back system as mentioned is everything behind that in the exhaust. The headers. x-pipe, and cat back will be better than the CAI. Since you're worried about noise, I would avoid any aggressive cat back systems. Your best option would likely be the titanium exhaust off of a Z06. It's lighter than your steel exhaust, and flows just about as well as any of the aftermarket options. However, it won't cause any drone or unwanted noises. It will be a bit louder when the car is at wide open throttle (WOT). A few things to think about with headers though. They do generate heat. As mentioned, an insulated tunnel plate will help with this (and will also improve handling). You may also consider some heat shielding for your spark plug and starter wires. Also, you can get the headers themselves ceramic coated or wrapped to help with any additional heat. Finally, you need to be aware that getting headers will require you to get a tune for the car. Without a new tune, you will have lights lit up on the dash. Plus, you won't really be getting all the benefits from your mods.

 

Suggest you get more detailed information from your buddy on what exactly he did. Normally lifters won’t change the duration of the valve lift. Perhaps he installed a camshaft or different ratio rockers. Need to nail that down…

On the intake…. The aftermarket intakes(filter housing) look cool but do very little, if anything, for performance. Their ads claim X more HP, yet you’ll not see them display flow bench tests. The choke point is actually down stream of the filter at the throttle body and intake manifold.

The fuel sensor is for tuning, but I’ve not had one of those, so I can’t offer much. I’ve had cars tuned, but they never asked for that. Does this shop have a dyno to run your car on?

BTW, all exhausts throw heat, it’s just that header tubes are very thin compared to the stock cast iron manifolds, so they release heat much faster in the engine compartment and near the floor. The tunnel plate and insulation kit are a benefit to all our cars, but even more so for headers. It’s convenient to have that done at the same time as header, because one needs to drop the exhaust pipes anyway to remove the tunnel plate. The stock plates are about 1/16” and do a poor job of insulating the floor and console from exhaust pipe heat. An aftermarket plate is 1/4” thick, so along with the insulation stuck to it do a much better job of reflecting the heat away from the floor and console.

If you can contact your buddy and get additional info on what he did it will help.