Fissile

I recently picked up a manual 2006 C6 Z51 convertible. I don't really know much about cars beyond the obvious. I can change oil and air filters and what not and that's about it.

I'm looking for things I can do to boost performance without breaking the bank. It's already got a Corsa exhaust on it (its only mod). I think I'm going to get an Airaid intake for it. I looked at the instructions and it seems mind-numbingly simple to install.

Is there anything else I can do myself pretty easily or not terribly expensive to have installed? Also, I'm only looking for things that have a low risk of trashing the engine and keep it street legal.

• Is there any value in an upgraded intake manifold without forced induction? (I understand this may require a different hood)
• What about headers? Would it be expensive to have them installed?
• I've seen mixed reports about dyno tunes. Some people claim wild gains and others are modest. Worth it? Any recommendations in the southeast NC / northeast SC area?
• Should I be worried about any of these when it comes to emissions testing?

Everything else I want to do is cosmetic (minor).

timd38

I have a K&N air intake and headers as well as a tune and have no problem with emission testing that is required in Wisconsin.

goatts

You said you wanted to boost performance. The Airaid will do nothing. Go with Vararam. Headers will give you 20hp but you'll need a tune. Go with high flow cats.

Fissile

Vararam ordered. What cats would you recommend?

0HinsonSuperCars

Headers, Vararam, Tune.

The cats will come with the x-pipe.

Seth

johnodrake

Carolina Automasters in Durham.

Best upgrade you can make for your car is a high performance driving school like Spring Mountain or Bondurant. When you can properly handle the 400HP you have.....

Be careful with the emissions. I didn't take the time to look up your county, but here in Guilford, you would fail emissions with headers.

Fissile

It had the exhaust when I bought it, but I'm not sure whether or not the cats were replaced with it. I don't fit under the car so it's hard to get a good look. Obviously I wouldn't buy anything without first figuring out what I've got on there.

johnodrake

You can see the headers from the top - cats too. Moreover, that is how the emissions tester sees the cats. He sees them, you pass visual, he doesn't see them, you fail. First thing on his list!

In the C5 you could get away with long tubes because the cats remained in the OEM location. Not so with the C6. Best you can do with the C6 is to install Z06 (or ZR1) exhaust. Not as good as long tubes but better than nothing.

dgoldenz

Nothing a $20 bill can't fix....or $50 if you're generous.

goatts

Are you going to install the Vararam yourself? Order the cats with the headers.

Here's an example, you can see the cats in the middle.

http://www.lmperformance.com/7385/74.html

Fissile

The Vararam looks like an easy install. I know what catalytic converters look like. We cut them out of my brother's car and replaced them with straight pipes when he moved to SC (no emissions requirements).

Why do exhaust systems like the linked one include cats at all? If you're not going to meet emissions requirements, then what's the point?

However, if headers are going to make it fail inspection, then I'm not installing them.

johnodrake

Sometimes, I guess. But you are asking the inspector to bet his liscense (and a big fine) for 20 bucks. Not to mention that bribery is a crime. But hey, not my butt on the line.....

johnodrake

It really isn't about meeting emmissions levels, it is about what the law (EPA) requires - even though the law may be dumber than a box of rocks. Many, maybe even most aftermarket cats will meet tailpipe test - heck, some may be better than the OEM. But there are fewer and fewer places that do tailpipe testing anymore. VA and NC use OBCD II and visual inspections.

Fissile

What does the on-board diagnostics actually report? And what might be considered a satisfactory test?

goatts

Some guys do not like the odor without cats. Vararam is easy but do your homework. Glue the seals in place with epoxy. The newer units don't warp but keep an eye on it. Make sure you place a thin piece of plywood etc to protect the condenser when cutting the shroud. Vette magazine has a good writeup.

Fissile

I bought a replacement shroud in addition to the Vararam. If I decide to sell the car in the future I want to be able to put it back how I got it if necessary.

dgoldenz

Or a wink and a nod if you're convincing.

sh2002

R.P.M (Ryan's Performance Machines) in Garner does great work on installs and dyno work. He knows Corvettes and how to make them run.

If you do go with headers make sure they install the back O2 sensors for visual. The back O2 sensors are turned off by the tuner to avoid throwing any codes but the computer the state uses can't tell they are turned off and they will be there for visual .

Bought my first Corvette '05 out of state with headers and highflow cats and had to put in the back O2 sensors because I failed visual the first time but passed once the back ones were installed.

Hope this helps.

Steve

Fissile

So after the air intake, next should be headers / cats?

What about after that? Apparently most people do custom cams, but I don't want to make any gross changes to the engine.

What about the intake manifold? Is it worth upgrading without forced induction or a cam upgrade?

johnodrake

If you don't have a CEL you will pass. (If you have had a CEL, you need several start clcles to clear the Not Ready monitors.)

Here are the NC rules:

A vehicle shall Pass an OBD inspection if:
(a) The Malfunction Indicator Light bulb check status is ok and
(b) The Malfunction Indicator Light bulb is not “ON” with engine
running and
(c) The Malfunction Indicator Light is not commanded on for any
Diagnostic Trouble Code and
(d) The number of supported readiness monitors that are set to “not
ready” does not exceed the maximum limits based on the vehicle’s
model year. (See note below)


8. A vehicle shall Fail an OBD inspection if:
(a) The Malfunction Indicator Light bulb check status is not ok
and/or
(b) The Malfunction Indicator Light bulb is “ON” with engine running
and/or
(c) The Malfunction Indicator Light is commanded on for any
Diagnostic Trouble Code and/or
(d) The Diagnostic Link Connector has been damaged, tampered with or
is otherwise inoperable.


Note: For model years 1996-2000, a maximum of two (2)
readiness monitors may be set to “not ready”. For model
years 2001 and newer, a maximum of one (1) not
completed readiness monitor is allowed.)


The manual here:http://www.ncdot.org/dmv/vehicle_ser...nforcement.pdf