LT4 Help me in answering a question regarding a cam and LT headers on my LT4.

[megatron]

Hi all,

This upcoming spring, I am certain to install EM's LT headers onto my LT4. Currently, all I have done is an open air lid with K&N and Corsa cat back exhaust. With this set up, I have dyno'ed at 300.4 RWHP.

I am also thinking about adding a cam, but am worried due to several reasons.

1. First, I am ignorant on how fool proof a cam install can be from a reputable installer. Can an installer tell if something is not right immediately before I drive out of the shop and blow up my engine?

2. Most of the searches here reveal people who want aggressive cams with a big lope and rough idle. I want something damn near stock, but with some additional performance in ET's and MPH. Any suggestions?

I'm thinking of the LT4 hot cam, but have heard either horrible things about it or great things about it. Which is it for my situation? Remember, I want and need to pass emissions.

3. If I go with the LT4 hot cam, what else needs to be replaced if anything?

4. Anyone have a sound bite of a LT4 hot cam at idle?

5. Best place to find the LT4 hoy cam?

6. Finally, what types of HP increases and ET decreases can I expect to see with an LT4 hot cam and my set up?

Thanks in advance for your responses and thanks for the education. Like I stated, I'm pretty ignorant on cams, but eager to learn!!

I posted this thread also on CF (Corvette Forum) in case anyone visits that site.

 

[Notorious]

If anyone's had trouble with the Hotcam, it wasn't due to the cam I'm sure. This is an excellent, very versatile cam designed by GM specifically as a performance upgrade for your engine. Idle is very civilized and has just a nice little lope. The driveability will be as good as stock, especially in a manual car. Computer tuning after installing will further enhance power and mileage but is not immediately necessary, the engine will still drive and run very well. The Hotcam is designed to be used with all of the components the LT4 already has, 1.6 roller rockers, your springs, etc. That's not to say that there's still not room for improvement, especially in the valve spring area. I would definitely recommend a new timing set, preferably the GM Extreme Duty set-up for the LT1/4 engines or a quality aftermarket equivalent.
Since you mentioned that you'll be adding headers too, let me suggest something that will work a little better for you. The EM is a fine piece, there's no doubt about that. But for a mildly modified engine you will make more torque in the low and mid range, without sacrificing up higher either, with a smaller set of primaries. There is only one made that I know of, Stainless Works. They are a top of the line product as well as having the advantage of being made, of course, from stainless steel. With the headers, cam and a good dyno tune, you should realize a good 40 HP or so increase.

 

[blue94]

I agree the "Hotcam" is a very good selection for performance in a daily driver. I added the kit(s) to my LT1 last winter and have been very pleased with the results. I would say to get a dyno-tune done after the install to get all out of the cam. After the tune the results were 314RWHP and 315 RWTQ.

Joe

 

[Vettelt193]

Cams are all cost/benefit really... If you want your cam to be close to stock, it probably isn't worth installing one (on a $$/HP ratio). In order to reap the benefits of a cam, you will have to trade off some 'street' drivability. Even with a hot cam, you will need a bit more throttle off the line, and you will notice the lope at idle compared to stock.

The LT4 has a really aggressive cam considering the idle and drivability qualities it retains. it isn't all that easy to install a cam in our cars, there is a lot of stuff in the way, so even though the cam is cheap, labor will be really expensive... this is why people that take the plunge into installing a cam are usually looking towards an aggressive setup. they usually are aware of the full cost, and are willing to trade off some of the drivability to gain max power.

hope this helps

 

[stgry1]

Yes I agree with the last statement. If you have the money and don't mind spending, then have at it. Might as well reprogram the ECU, port the intake and the heads etc. For me and my misealy budget, A lil race fuel and a nice 100 shot of N2O will do me just fine. Aprrox $1k to set up properly. Where else can you get those HP numbers for that amount of money?? Oh ya...and if done properly...IT"S SAFE!!!

 

[boulderlt4]

I didn't want a huge cam either, but wanted more for my money than what the hot cam provides. I went with a custom cam that my builder designed.

Here are the specs.

Intake
Valve Lift--.570
Duration--286
Camlift--.380
Duration @.050--224

Exhaust
Valve Lift--.575
Duration--294
Camlift--.384
Duration @.050--232

Lobe Seperation --114


When I put this on my LT4 with my catback and the 1.6RR's, I got these results...

354.1 RWHP
319.8 lb/ft

Those were on a Mustang Dyno also!!

And here is the dyno sheet with the cam in.

Great cam, only reason why I'm not still using it, is that I needed a bigger one since I built the 383 stroker. This cam is for sale if you are interested!!

 

[93Polo]

Boulder was that on stock manifolds? Good #s

The Comp CC503 is very close to Boulder's cam with a 224/230 duration. I'd go with a 114LSA since you want a mild idle.

The stock Lt4 cam isn't really radical:

The LTx Cam Specs are as follows:

'92_____205/207 .451/.450 117
'93-95__202/207 .450/.460 116
'96_____200/207 .447/.459 117
'96 LT4__203/210 .476/.479 115 (with 1.6 rocker)

So if you take away the 1.6 rockers you're left with

'96 LT4__203/210 .446/.449 115

Specs were found on another forum.

The best advice I can give you after doing H&C to a car is find someone with the cam you are thinking about close to you and go for a ride. The HOT Cam has very little down side IMO but my views of a big cams may not be the same as you.

 

[Vettelt193]

I didn't realize (never put 2+2 together i guess) they actually rated it with the 1.6's like that.

you still gain the speed with the bigger rockers though, wich is nice.

 

[boulderlt4]

Boulder was that on stock manifolds? Good #s

The Comp CC503 is very close to Boulder's cam with a 224/230 duration. I'd go with a 114LSA since you want a mild idle.

The stock Lt4 cam isn't really radical:

The LTx Cam Specs are as follows:

'92_____205/207 .451/.450 117
'93-95__202/207 .450/.460 116
'96_____200/207 .447/.459 117
'96 LT4__203/210 .476/.479 115 (with 1.6 rocker)

So if you take away the 1.6 rockers you're left with

'96 LT4__203/210 .446/.449 115

Specs were found on another forum.

The best advice I can give you after doing H&C to a car is find someone with the cam you are thinking about close to you and go for a ride. The HOT Cam has very little down side IMO but my views of a big cams may not be the same as you.

Cam, Catback and the RRs, everything else was stock!