phDiesel

'96 LT-4

I'm planning on doing a mild Cam and 1.6 Ratio rockers this January.

Is it required to do ECU tuning to optimize for the extra lift and duration?

How does one go about tuning the comps on these cars?

gdl2165

The LT4 has 1.6 rockers stock so you can save yourself some money there unless you just really want some aftermarket ones that are adjustable or non-self aligning. You don't state what cam you're looking at, your choice there may affect whether you need the adjustable rockers or not. The GM Hot Cam was designed as a direct drop-in for LT4 motors so if you go with that one you can reuse the stock rockers, push rods, and springs. A lot of people will recommend new springs and lifters regardless, I reused mine at just over 100,000 miles and haven't had any problems with them.

Yes you're going to want a tune. There are a few places that do dyno tunes still but it's more common to do a mail order. pcmforless.com, Moe Bailey in San Antonio, Ed Wright in Tulsa, fastchip.com are all possibilities. Some of those do either dyno or mail.
For the mail order stuff you can pull your PCM and send it to them, they program it and send it back. I did pcmforless on mine, they offer the option to have them source a replacement PCM so you don't have to send them yours, you just have to pay the core charge. I went that route on mine partly so I could be 100% certain I didn't lose the LT4 knock module in my stock one. I don't know if they all offer this option or not, but that LT4 module is expensive to replace so you definitely want to make sure you don't lose it.

phDiesel

Good info.

I was looking at a Lunati that had VERY similar specs to the GM Hot Cam that was in Parts For Sale side. Super good deal at $250 shipped.

It's good to know that it already has those rockers, though.

I've also been looking at headers but the bolt-on selections are pretty limited and I'd rather not put shortys on it because I feel like that wouldn't be worth the money.

gdl2165

When I did mine I looked into the Lunati cam as well. It does have similar specs but has a bit more lift so it won't work with the stock springs. If you're planning springs anyway it could be an okay choice but if you're wanting to keep the stock springs you'll need to stick with the hot cam. Check ebay, you can get it there for about $250 shipped as well.

Shorty headers are generally not worth it unless you get a screaming deal. I did shorties on mine because I did get a great deal, plus my stock manifolds were developing cracks so I had to do something. Mine's a convertible so as far as I could determine from research it's impossible to do longtubes with cats and keep the x-brace underneath so I had to do shorties. Longtubes make good power but they're not cheap.

phDiesel

To be completely frank, as superficial as it is, I'm trying to clean-up the engine sound a little bit. I'm alright with not picking up power if they reduce some of the "truck like" sound I get from my LT at lower rev ranges.

When you did the switch did it alter sound at all? Looking for a little more growl.

gdl2165

I did the cam and shorties at the same time so I don't have a direct before/after comparison but my gut feeling is they don't really change the sound much. For a cheap growl you can do muffler eliminators but I don't know if that eliminates the "truck like" quality you're talking about. I did those on mine and I really like them. If you want something a little more exotic sounding, the sound clips I've heard of either an X-pipe replacing the resonator or the full Corsa cat-back exhaust seem to be the ticket.

Post up your location, maybe there's someone near you with some of these exhaust options you could listen to. Otherwise your best bet is Youtube with headphones or a high quality sound system.

phDiesel

If is basically a SBC at the end of the day so I can't hope for the world here.

The PO had some form or fashion of Magnaflow exhaust out on it but I'm not sure I like it. It drones pretty badly at 2,000 rpm and doesn't really offer a lot of sound to compensate for it. I have some people think it's stock. I've heard that Corsa and it sounds savage. I DD this car so it's got to be a jack of all trades. I'll do a little digging and hopefully have enough pennies in the piggy bank for what I decide on.

Thanks for the info though, much appreciated.

steven mack

I would be very careful on what exhaust mods you choose.You already have a drone at 2000 rpm.If you choose a system that makes it any worse You won't want to drive your Vette on a daily bases.

phDiesel

It's such a delicate balance. My solution has generally just been to drive faster when I'm on the highway.
Would adding a resonator clear that up a little bit?

steven mack

I believe it would.