I've had my Z06 fixer project for less than 3 weeks and of course I'm planning some upgrades for it as soon as it comes back from body and paint. Im looking to upgrade:
Headers
Chip/controller
Tires


1) What brand of headers will net me the most HP? are there any 50 state legalLT headers for the C5? if not, what is the best short tube header? (CA emissions laws:-(

2) I was wondering how wide of a tire I can fit in the rear on the stock Z06 wheels (I was thinkingmaybe a 315/35 or 30-18or something like that).

3) Last but not least... what type of chips or controllers would work best on my car? What do you all use and how do you like them?

 

The amount of power you get from any good long-tube headers won't vary that much from one to the other (people selling it might disagree but then you would expect that . . . ), and any difference someone saw on one car might not be the same on another car in different circumstances. Recognize that the longer the tube, the lower the key RPM the headers help most: lmost of the advantage of long tube headers over mid length is in mid range torque.
It is much more important to look for a good fit and good assembly quality than worry about HP differences. I would go with a proven name . The best headers I ever had on any car were Lingenfelter stainlesslong tubesfor my C5: the first mod I did on it, they were works of art and a perfect fit, but pricy. Diameter is important too. On a stock engine, use 1 3/4 inch diameter pipes, only use the bigger 1 7/8 on modified or stroker engines; on stock engine the bigger diameter will kill the low end.

The biggest tire I was able to get in the rear of my ZO6 was a 305. 315 drag radialsdid fit although it was getting a bit wide for the stock rim, but rubbed in the corners (the car was lowered about 3/4 inch so maybe. Lingenfelter makes a wheel-well tubbing with shock relocationtkit hat is not terribly expensive that will permit up to 345 tires on the rear

No aftermarket chip or controller is needed for the C5, you can have a good shop retune the ECM with the LS1 edit program. There really isn't much there to gain but you can sometimes pick up 8 HP or so. You definately need a retune to get the most for any mods, though.

 

As Lee mentioned you can go wrong with Lingenfelter...I have also heard good things about LG Motorsport LT Headers, just to give you a second company to look into.

 

Thanks for the info Lee. Does it really kill that much bottom end going from 1 3/4 to 1 7/8 primaries? of course I've definitely experienced the difference between a 1 5/8 and 1 7/8 but thought the difference would be negligible between the3/4 to 7/8.

I'll check out Lingenfelter's parts. I've spent a lot of $$ with them on other cars and know they make quality parts. I've also heard good stuff about LG'sbut haven't really heard of them until a few weeks ago whenI started browsing Corvette forums.It doesnt look to terribly difficult to swap out the headers every 2 years when I need to smog it so I think i will go for the LT's.

Thanks again for the info

 

The difference in 1 3/4 inch primaries on the headers from 1 7/8 is big enough you will feel the difference at around 3500 - 5000 RPM on a stock engine. Either will be much better than stock, but the smaller pipes have just enough size to limit the gas transit speed to the collectors for really good operation in that power band, the larger primaries seem to let it flow to much and you don't get as much really pressure/resonance whatever you want to call it help with gas evacuation. As you say it is not the difficult to change out headers and you can always sell a used set in good condition (as I did), so you might think about doing what I did: install a good 1 3/4 inch set now, then upgrade later when you have heavier other mods.

 

When would 1 7/8 become better than 1 3/4?

 

When you have a stroker or boosted engine, a really extreme heads and cam kit, or have otherwise crossed north of about 480 RWHP. I didn't switch out to mine until I was at 530 RWHP.

 

I forgot to mention... I found out the previous owner installed a Thunder Racing cam .563-ish lift. its a split pattern and I forget the rest of the numbers off the top of my head. I plan on head work at some point in the future but not sure exactly when. I'm in a dilemma right now... I think i will eventually have the mods to justify the big tube headers but not at the moment.

 

One of the things to keep in mind when you are doing mods is that a stroker short block is often not too expensive.Going all the way to 427 cubes (LS7 or C5R) or beyond (the new LSX decked block, which can do to about 480+) is very expensive (I just had to have exactly 427 cubes on mine, for traditiona's sake, but it cost me dearly). But , if you shop around and buy well,a stroker short blockLS2 (402 cubes) often costs only about as much as a good heads and cam kit. It won't add as much HP as a good heads and cam kit (only about 10-12% as compared to 16-20%), but it adds torque and HP across the entire engine RPM range, particularly down very low, where no other type of mod can give you anything extra. Low end torque makes a car very staifying to drive on a daily basis. And most stroker kits have premium rotating parts so now you can feel confident when you do other mods, and of course each of them will now give you another 10-12% more power than they would on a stock displacement.

 

What heads and cam do you have Lee?