boostd4

I test drove a car I'm looking at buying today and it has a stock 99 LS1 shortblock, GM MLS gaskets, GTP Stage 2 5.3L ported heads, and a 225/225 112lsa cam.

I was kind of dissapointed in the low end considering the 5.3L heads supposedly increase C/R (and therefore torque), and definitely dissapointed in the cars ability to hold a good idle. I'm thinking both of these issues might be solved by a cam swap.

I'm looking for a cam that has stock like smooth idle and doesn't lose any low end torque.. in fact, MORE would be better. I'm not revving this thing beyond 6500rpm, and would like the most usable torque I can make.

Thanks!

rms25thta

I am interested in hearing some opinions on this one myself. I am looking for a cam for my build that will have great low-mid power.

LS1-NAVY

iTrader: (1)

well holding the idle thing is all in the tune so it needs tuned but it your are going to change the cam do that then tune. i would get a hold of pred-z on here he is really known for specing cams around here

boostd4

The car I drove supposedly had a really good tune. Perhaps the 112 is just too choppy. outside of the LSA for idle purposes, what specs should I be looking for in a cam to make the most low end torque?

LS1-NAVY

iTrader: (1)

i think the proven TR224 on a 112 or 114 would also be good. I would go with the 114 LSA if you want a smoother idle. I also think before you get a cam though you might want to try some gears, it will make a huge difference 3.73 for an auto or 4.10 for a M6. also if you r an auto guy try a stall that will help alot to.

Sharpe

iTrader: (7)

That cam and those heads should be great for low end.

How many cammed cars have you owned/driven? I think you're chasing the dragon here. LS1's don't really have the same "feel" as a 3rd Gen 350 or an LT1. Their power sneaks up on you because it keeps making power through the RPM's. If its curve fell off real early like those other engines, it would "feel" more powerful.

Tune/exhaust is the first thing I would inspect. I'd keep those heads and cam for what you want.

MrElectric03

iTrader: (71)

TR224 on a 114 would be ok. The thing is typically when you lower the LSA giving it a choppier idle it gives it better low end, and when you raise the LSAit moves the power higher in the rpm range.

I doubt the compression is very high, if you are doing a cam swap id pull teh heads and mill them and toss some cometics in as well.

And everybody has a "good" tune. How many guys would take their car to a guy they know cant tune.

boostd4

Correct me if I'm wrong, but the closer the lobe separation angle, the MORE overlap you have, right?

I thought the more overlap you have, the bigger your top end will be. Basically at low rpm, the longer the exhaust valve is still open while the intake valve is (especially with headers that allow gasses to escape faster than stock manifolds), some of the fresh intake charge can actually escape out the exhaust valve and you lose *some* of the fresh oxygen for the combustion cycle. As the motor speeds up, the air has less time to escape during overlap and the motor builds pressure in the exhaust which also keeps the intake charge from escaping.

This, I thought, is why a lot of people feel that the car loses a bit of low end torque when they go with long tubes, as well as some cams.

If that assumption is correct, wouldn't a larger LSA (115-118 like perhaps the smoothest TR224, or perhaps the GR2-3) mean more torque at 1200-5000rpm?

caviness

iTrader: (14)

did you buy the car???if so id go have the tune checked first,and is it a4 or m6??

Jason 98 TA

iTrader: (4)

Here's a dyno graph of several different camshafts near the same size so you can study torque with different camshaft.

boostd4

M6. On the test drive, I think a lifter froze. It drove fine for the first 15-20 minutes and it was fully warmed up. THen there was this louder tapping noise. I limped it home and it felt like it was missing on a cylinder. As soon as I got out of the car to look under the hood, the noise stopped on it's own. Needless to say, the valvetrain is NOISY. I know the 98-99 cars have really noisey lifters/valvetrain, but this one seems really noisy. I was told I can swap in a new set of LS6 lifters and that will help. I was also told that the Stage 2 GTP heads haven't had the springs checked in 40k, and could probably use new spring (previous owner liked to rev it to 7k frequently).

Regardless, if I have to pull the head to do the lifters, I might as well swap the cam.

I think I'm pretty much set on the LPE GT2-3 cam. Supposed to be pretty agressive though STOCK idle. Not great for high horsepower, but with the ported 5.3L heads w/OS valves and good tune, I only want to make 400whp (car also has LS6 intake, JTR longtubes).

Does that seem reasonable? Car hasn't been re-tuned in over 4 years, so I'm sure there is a lot to be gained from that. If I'm planning on changing the cam, I'll just pay for the tune once, after the cam.

caviness

iTrader: (14)

id say if thats the cam you want do it and new lifters and head gaskets and check the pr length.maybe some thin gaskets for heads,and check cc on heads might need to mill them a little for compression you'll have to check,you should hit your goal of 400 pretty easy.

transaman98

iTrader: (16)

Why not do a reverse split with a tight LSA? I wouldn't worry as much about having a smooth idle as I would finding a tuner that is capable of making whatever cam you go with idle and drive like you want it. Just my .02.

Nitroused383

iTrader: (10)

Cams are designed for the rpm range they run in. High amounts of overlap do not always mean they are a top end only cam. Its all about the valve events, usually 114-116 LSA cams are going to have crappy low end, smooth idle and more top end. Once again all valve events. I feel my 224 cam is a very good torque cam with no loss of power down low and pulls really hard starting around 3000. My cam has more overlap than the Torquer V2 cam. Overlap does help high rpm scavenging and over rev, probably why I am within 3hp from 6000 to 6500 rpm.

boostd4

After talking to some tuners, it seems the tune solution for lumpy idle is to RAISE the idle. My car has LT's and no cats, it already stinks of exhaust at idle, FME raising the idle makes that worse. Also, to "tune-out" the falling revs catch problem, they make the revs fall slowly when shifted to neutral, and I don't really care for that option either.

Perhaps a small cam is for me, and maybe it can be tuned for a few more low-end ponies since I can run 93 all the time, or I'll look into milling the 5.3L heads a bit more.

LS1-NAVY

iTrader: (1)

not bashing on the new lobe but i see the new 224's trq is lower in the midrange a little

95CamaroLS1

ha i dont know why there cant be a cam that has the title "torque king, for DD drivers". Cause i am looking for a cam with good low end, mid-range torque. Except i want the loud obnoxious sound with choppy idle..

bww3588

iTrader: (49)

torquer V2.....good all around DD cam with a nice choppy idle.

00MaroonZ28

iTrader: (3)

Reverse split cam!!!!!!!! Great low end torque.

garygnu

compcam LS lobe 54-455-11