Springer's LT4

Has anyone put a LT4 hotcam in their otherwise stock LT4? What kind of gains did you see? Anything else need to be done like reprogramming or is it pretty much just a swap in/out?

Anyone have any idea on the labor involved for something like that?

Thanks!


Jim

vader86

Id guess, from comparing the two cams, you should get maybe 40-50hp.

Jay Axson

Just put in because it is fun :D

rcolling

I think NoGo did it to his and realized about 30hp gain. I know he's got me thinking about this one...

ericcer

We can talk about this when you come over for a test drive. I did the job a few weeks ago.

Springer's LT4

That'd be great Eric... can't wait to see how she runs!

Hib Halverson

The LT4 "Hot Cam" bolted into an otherwise stock LT4 that still has cats and a stock exhaust will add 10 maybe 15 hp.

While it's a great cam profile designed to work well with the existing LT4 valve gear, one of the problems with the LT4 Hot Cam is that it was designed for use in road race engines with no cats and either a very low level of exhaust restriction or open exhaust. It needs high rpm and very low exhaust back-pressure to work well. Stick it into a stock engine with cats and stock exhaust and you may see an increase but some of the potential increase will be blunted by the high back-pressure that's present.

Another problem with the Hot Cam can come in states where IM240-style exhaust emissions tests are required. The LT4 Hot Cam's increased overlap sometimes causes problems with misfire at idle and that will usually flunk a smog check. The solution is to reprogram the ECM for a higher idle speed, usually about 800-850 rpm. Do that and the misfire-at-idle problems usually disappear.

Lastly, the Hot Cam makes all it's extra power at high rpm. To really see its benefit the LT4 rev limiter needs to be raised about 400 rpm. Again, that requires reprogramming the PCM.

Nathan Plemons

On my LT1 putting in an LT4 Hot Cam kit gave me 44 horsepower There are a few ways to look at that. You can say that I saw more of a benefit because my car didn't already have roller rockers. You can also say that the LT4 stands to gain more because of it's better heads and intake design.

I'll agree that the Hot Cam prefers low / no restriction exhaust, but it will also do very with full exhaust. So far the best increase I've seen was the cam alone. I've gained 44 hp with the cam, 23 for headers, 30 for heads. Bang for the buck in my case was the Hot Cam. Also I only spin my motor to 6300 which is less than an LT4 anyway isn't it?

The Hot Cam seems to be a very adaptable cam. Sure it runs better with heads and a low restriction exhaust, but it will still run very well without. For your LT4 you CAN use your stock springs and such, so you can get away with the cam alone. I don't think you'll be able to beat the horsepower you'll gain for a mere $180 for the price of the cam.

ericcer

That is not true according to the many people that have done just that with dyno sheet to prove it. It is usually 25+rwhp. All you have to do is use the search function on this board to find out.


[Modified by ericcer, 11:36 AM 9/27/2002]

Springer's LT4

25 hp I'd be very pleased with.... I do plan to do some form of Catback... or just Flowmasters with stock tips... but thats about it for exhaust. :cheers:


[Modified by Springer's LT4, 1:29 PM 9/27/2002]

Springer's LT4

Well... I got one quote from a supporting vendor of 975 bucks labor to change the cam... 1200 labor if I do the springs also. :eek:

1CanuckVette

I did mine in the spring along with some minor port polish and the car runs great, still need to get it tuned for the full affect. No dyno sheet yet, but the car has run 13.1 at 111mph with a 2.2 60ft with an average driver. The cam really changes the way the car pulls up top, but you do need to reprograme for some extra rpm. At the track I have gained 5mph from last year, the 60ft's suck because of the old track and the GSC's that won't hook. On the street I've managed to hang in with a 02 Z06 by a car length up to 200kph. The best part is the lumpity lump at idle :yesnod:

Nathan Plemons

Do you have about a week's worth of time and can you spin your own wrenches? It's really not all that hard at all and it will save you a lot of money.

Springer's LT4

I can do the work myself... built plenty of engines in the past... just don't have a place to do it. I've got a garage with my apartment, but your not suppose to do any type of work. I've gotten away with minor stuff like oil changes... but doing the cam might be a tad more then I can get away with... esp being in FL it's not like I can close the garage door and work in that heat :)

silver & red CE

$975 labor for the cam change and an extra $225 labor to change the valve springs?!?!?! Here in Chicago, one of the pricest labor markets I've ever lived in, last time I checked it was less than $700 labor for a local shop to do the cam.

Eric

Springer's LT4

dang!

Maybe I'll call around to other speed shops... it is only a cam swap... not like it's any different on a vette then any other LT1.

Nathan Plemons

On my car I can probably do a cam swap in one FULL day if I really worked at it and had some help. But I guess rules are rules. If you've never done it before there are little quirks. First time it took us a week and a half, next time I had it apart I could have had it done in 3 days. Now I'm down to a day or two ;)

Ah the joy's of having to fix the car EVERY FREAKIN DAY!

silver & red CE

That's the key. Around here when I check out a specialty Vette shop, the prices are stupid. The quote I got was from a shop that does both Vettes and Camaro/F-birds. Since the economy sucks, I'll just do it myself.

Eric

Shriker

I remember someone on here doing just the Hot Cam kit and nothing else. I believe he gained 25 rwhp on his LT-4. It would be a good idea to get a good tune anytime you change cams. The kit comes with LT-4 springs etc and you would not have to change them but it would be a good idea to put in good pushrods, springs , retainers etc when you do the cam along with a good tune.

Generally a decent LT-4 dynos around 295-300 on average and with long tube headers/catback, Hot Cam, lid/filter, and a good tune you should see around 350 rwhp. The only real limitation I have seen with the Hot Cam is that even with worked heads/intake our 350 cid LT motors only seem to get up to around 370-80 rwhp , which is not bad just could be more.

I have seen LT-4 heads/cam cars make 415-20 rwhp with more aggressive cam setups........ :seeya

GS470

The previous owner of my car installed the Hot Cam into a bone stock engine, all they way down to the exhaust and computer program. Car had 294RWHP before the cam and 326RWHP after the cam.

Is it safe to spin a stock LT4 bottom end up to 6700rpm??? My computer program is still stock and I was thinking about bumping my rev limiter to about 6500. Should I have it set higher?