LT1 cam timing, Will retarding it save my 901? Options

[bondo]

An LT1 in stock form develops 325 ft-lbs of torque.. 25 over the reccomended limit for a 901. I've read that retarding cam timing will shift the powerband up in RPM and reduce peak torque. Is this something i should consider doing? Will it mess anything else up? I plan to use the stock firebird EFI. (It's a 93, so it doesn't have a MAF sensor, and the chip has to be replaced to "chip" it, instead of the later LT1 reprogrammable type)

[Andyrew]

From what I understand, what breaks the trani is an inital hit... If the engine runs like a stock turbo.. (laggy down low.. and has a flat hp band, and a flat, increasing radius, tq band...) Then it should be a ton better for the trani...

It could save it... but you know as much as I do.... lol.

FYI, Im going 26-28 degrees on my timing. I was going to do the "4 degree's" whatever for the cam timing, but I didnt have an adjustable bracket! Oh well...

Heck, I'd do it.... but dats me...


Im also looking at turbo systems on ebay for 300 bucks... but THATS me as well.. lol

[bondo]

Flat incrasing radius torque band? Isn't flat the biggest radius you can get? I think the LT1 may be able to squeeze more power through a 901, because it's a very smooth engine with a flat torque curve. I drove the firebird before I pulled the engine, and it was amazing. It's hard to imagine how much fun it will be in a lighter car. It would pull contunuously from just off idle to 5000 RPM, with no noticable torque peaks. You just stick to the back of the seat until you let off the gas. It's gonna be a blast.

[bondo]

bump?

[iiibdsiil]

I don't know about retarding the timing. I have seen them apart, and usually, if you are one tooth off on stuff, you will bend valves.

Then again, I have never degreed a cam before. I have seen it done on a 911, but I can't say that the LT1 setup is anything like that. I thought the Chevys were slide it in, put the chain on, more or less. I could be completely wrong.

But, if that reasoning is correct, then you would have to physically put it one tooth off, which I think would be waaaay too much.

Another option would be to go to PCMFORLESS.com They can make you custom chips. I am sure you can just have them retard the timing to get you to the HP you need. They are really great guys over there, and know their stuff.

That option is $150, plus $20 each upgrade, and it is a piggy back system. They are one of the better people at doing it. There is a different guy for the ECUs than for the Chips, but I have never heard a bad thing about Bryan Herter, who does the ECUs.

I think that is a better option for you. Or maybe you can pick out a cam that will just move the powerband up higher. You can put the 1.6 roller rockers and valve springs in, and make it rev a little bit higher.

Just a couple ideas. I had an LT1 in my 95 Caprice, so I know a pretty good about it. At least what I can read, I never had to do anything to it, it just ran and ran. And I am sure there is someone here that knows a lot more than I do.

[charlesmac]

Check out www.lt1tech.com . Theres a lot of good info on that site. I've been checking it to help with my '95 T/A. They have info on lt1 swaps as well. good luck

charles

[bondo]

I think to be able to adjust the cam timing I would have to buy an aftermarket adjustable cam sprocket. I looked in to different aftermarket cams, and some do indeed move the powerband up, but they all seem to increase peak HP and torque. Most also require different valve springs and rockers due to the higher lift. I also have looked into the LT4 cam, but I don't know how it would perform without the heads/rockers/springs/valves/intake that it was designed to work with. I haven't been able to find any info on the performance of a stock LT1 with an LT4 cam.

[bondo]

That looks like a great site, thanks! I wonder why I didn't find it through my LT1 searches.

[iiibdsiil]

http://impalassforum.com/cgi-bin/ultimateb...ic;f=1;t=007888

Here, I just posted it up on my other forum I visit, we'll see what they have to say.

[charlesmac]

I don't think the lt4 cam would give you much more power, but it might move it where you can use it more. It seems the consensus from the lt1 guys is to find a cam that works best for where you want the power. Something about "it's all in the combo"? (IMG:style_emoticons/default/biggrin.gif)