O.k. if you have seen the answers to this in LT1 tech, leave it alone. Let's answer this question intelligently In advanced tech. Seems to me you get your head bit off in LT1 tech to say anything that the lemmings don't agree with.

My thoughts:

TPIS is right on, they don't mention anything to sell to anyone in their answer, just a honest answer.

I think that on stock LT1 heads the ZZ3 cam with 1.6's is the way to go, seems to me that it has the same MPH potential as a Hot Cam but makes more TQ. Other than it raises the DCR with the ZZ3 cam, and there is very little overlap.

Now add some CFM to the heads, i.e. LT4's you now have 200cc heads that flow 240cfm, not a whole hell of alot of velocity there. Relative to say a 300cfm 215cc port. But more flow.

A 218/228 cam with .525/.525 lift (1.6's) 112 LSA
vs a
208/221 cam with .512/.544 lift (1.6's) 112 LSA

Seems to me that from 5500-6500 the Hot Cam would be better, but the average power from converter stall or clutch drop (and not some insane 6000rpm one ;-) ) would go to the ZZ3 cam.

I don't think that 10hp max at peak is really worth it. Less vaccum at idle, less average TQ, lower DCR, less driveablity.

Going to a larger cube engine, with better flowing heads, I would like to see a 215-225 duration intake and 225-235 duration exhaust lobe. Which yes, the Hot Cam falls into, I would just like to see more lift.

A Hot Cam does work in a LT1 w/ Stock heads, but it seems to me that the bigger is better theory of engines and their related parts has infected the LT1 tech forum and my opinion is that it's not the best for all parties out there. This is kind of basic, but the way that this forum is run reguarding differing ideas and the mutulal respect for one another should make a good conversation. In the end hopefully help out some guys reading this, maybe bring some guys who don't get some of these topics into a question that is directly related to them and their ride.

So what do you guys think about this answer? What would you advise?

Bret

I've come to realize that this post gets some old readers from time to time, which honestly amazes me. When I talk to guys and they reference this post after this long, 2 times in one week I should go back and add some thoughts to this.

The basic purpose of this thread was to have a cam discussion on what works best for most of the people. Hence throwing a wrench in the gears and saying the Hot Cam SUCKS! Looking at the length of this thread I think that it worked.

Depending on the head setup of your car and the cubes along with the RPM band you want to run in the cam will be different.

For a stock headed 6,500rpm (or so) shift point, I've worked on a cam that will give you both good power and good TQ. It's closer to the Hot Cam than the ZZ3/4 cam in duration, but with the rest of the specs and the modest lift it should compete with the larger cams like the CC306 in HP but make much more TQ. As I said above taking a loss on 5-10hp at peak but gaining 20 ft lbs thru the whole mid range is going to be a faster car. The basic premise of this orginal thread is basically what I thru into this cam design, it's just more radical to eak out more gains.

Going in and adding a good valvetrain that will hold up to this is also a good idea, and that's what's going to keep it making power above 6K. The only semi drawback to this cam is the lumpy idle like what a CC306 has, which I can vary to some degree for you.

The cam is the BRE-M1 cam. So if you are interested give me a e-mail. Or if you just want to shoot the **** about cams drop me a line.

 

Bret,

I think TPIS answer is a load of crap.

The hot cam is a pretty small cam in my opinion.
Yes the hot cam will be a pig (at low rpm) if the computer is not programmed but that goes for most after market cams with LSA of 112. Remember your pcm is programmed for a smaller cam with a larger LSA of around 115 –116. I have talked with TPIS on occasion and I believe they are into selling their own stuff (that goes for most companies) but their answer holds no water and it’s a load of crap.
If you do not plan to reprogram your pcm then I would stick with a cam with a LSA of around 114.

I just recently rebuilt my motor and did a few upgrades in the process and one of them was a bigger cam. (Custom comp extreme blower cam 224/236 with 114 lsa). This cam idles really well (at 900rpm with a little lope) and had no bucking or surging problems. (All this with stock programming) I did not install my blower until I had about 1500 miles on it.
To tell you the truth I was really surprised how well it preformed with out the blower and would recommend this cam to anyone who does not want to reprogram their PCM. (but with any cam change you will not get max power unless you reprogram the pcm)

I know a lot of people who run LT4 hot cams who had the pcm reprogrammed without any problems. In fact most step up to a bigger cam because is to small. I thumb my nose to anyone who tells you that the lt4 hot cam is to big .

Jim

 

I think it is to big for a stock set of heads.

Why? Well WTF would I want to add 10deg of duration on the intake to gain .010lift? and on top of that I can have more lobe area in less duration for the exhaust.

I know that a ZZ3 is a better cam than a Hot Cam by a ton. If I'm going to the 218 range for intake duration I'm going to get my own cams made because .525 is not enough lift for well ported heads. Hell a 214 with 1.6's can get .565.

Really the LSA is not the magic for the ECU it's the overlap, I would bet that the ZZ3 overlap is alot closer to stock than most of these super big duration 114LSA cams are.

I'm building a 383 now with a duration similar to yours but on a 110LSA and it should idle really well at 900rpms, there is alot to it. Meaning that there is more than just LSA to the idle, driveablity deal.

AS far as a blower goes, you could most likely use a ton more duration on that cam, I would expect that it would make a decent N2O cam though.

Just my thoughts, not that I claim to know anything about cams.

Bret

 

I think there is some validity to what Bret is saying, it just depends on the use of the car. Yes, people want TOP END power. It's useful at the drag strip and "races from a roll".

My gripe with the HOT cam is I think its advertised duration must be really high for it to lope the way it does. My gut says a bigger cam with steeper ramps would actually idle better and help keep some of the low, low end torque simple because it doesn't overlap as much.

Another comment - look at the exhaust duration! 208/221? That's 13 degrees different and with the intake side so small, it makes even less sense. It seems TPIS may have discovered through testing that LT1 heads require a heavy bias on the exhaust side to make good power. I've heard this cam idle in a blown car - it doesn't idle that great.

It seems every cam I've seen on a 114 idles well. It is quite telling as it show how much of an effect overlap has on vacuum at or near idle.

Also, people throw around "tuning" the low end of the HOT cam. You can't do much tuning - the MAF handles all fueling. The only changes you can make is timing and if you really don't like the idle, you can raise it's RPM and even try "WOT" tuning your idle (nice way to fool the car into keeping it open loop while controlling fuel with PEvsRPM). Other then what I mentioned, little else will change low RPM characteristics as it is pretty well established the VE tables are not used in closed loop with the MAF working.

That's my 2 cents...

-Alex

 

No offense to anyone but I have to disagree that the hot cam is too big for the stock heads 350 combo. (I think it’s just what the stock heads need to make some decent power).
I run completely stock heads on my car and my other friend who runs the lt4 hot cam set up runs completely stock heads and stock exhaust manifolds…. And he was still able to click off a 13.00 at over 109 (nothing else expect for cat back exhaust) traction was the problem for not getting in the 12’s. Oh did I mention that he drives is car every day in traffic etc. the key to running this cam or any other after-market cam is programming. (Which makes a huge difference on how the car idles and runs at low rpm)
Yes there is no denying that the stock heads have much left to desire but they are also not as bad as many think.

 

Alex, on the low RPM timing is almost everything IMO. I know because even a degree or two here or there can make a huge difference at low RPM in a cammed car. I kept trying to re-capture magical torque off idle that I had with my, plenty larger than weenie cam, but kept running into ping on 91 MTBE. I am talking about a HUGE power difference, it would pull the car hard forward just by putting it in gear.

I unfortunately though never found that magical timing sweetness without the ping, and dont know very low RPM torque numbers. I made about 325 RWTQ @ 2500 (dyno run start) and 385 peak, with a dying opti.

If your not pinging, your fuel is going to be somewhat close. If your BLMs aren't split like mad and the IAC counts are ok, all the rest is in the timing.

 

I likewise think its ridiculous to call it too big, but it depends I think on what engineering end we are talking about. The original discussion had to do with a bit of lag between full throttle, all kinds of cars have this issue. I've been in a HOTCAM car getting only about 10 MPG with a mail order tune, but it still ran great on the street as far as feeling goes, it pulls very nicely even with modest throttle input.

If we are talking about the ultimate in overall efficiency then I dont see a reason to look into what TPIS is saying, otherwise I look at it in the same light as all these people that say 230+ intake duration cams are pigs on the street and undriveable with stock rear gears (M6 car), because its usually non-experienced or poorly tuned car people that say that. We all have different opinions on what is acceptable torque and where the TQ is though.

 

Hmmm...that's some good info right there. I've been wanting to play with my timing numbers under 1,500 for a while now but both my of laptops won't run Tuner Cat or LT1_edit! Grrr...

So, adding like 1-2 degrees really made THAT much of a difference? My car is very INsensitive to timing changes (it pulled 12 degrees one time because of a code on the dyno and it lost under 5rwhp).

-Alex

 

Not to "front" on anyone opinion here...

but...I think this discussion is kinda apples to oranges. Look at what the HOT cam is designed for. Max tq and hp on stock heads? no. Could there be a better cam for torque and power? yes. Does the HOT cam suck? no. Is the HOT cam too big for stock heads? no. Is it a great cam (aka key word here is package) for a stock headed motor? YES.

I dont really see anyone getting a better deal than a HOT cam kit for $475 which includes cam, springs, locks, and 1.6rr's. That is a great deal for someone wanting to keep it at that level of performance.

Personally I have driven some well tuned HOT cam cars that make very good tq and hp. Low 12s at 112-113 in a stock headed motor is pretty good.....killer if you look at the price of the kit.

If you went and purchased a cam, rockers, springs, etc...all seperatly in a package that would make more power you are looking at $800.

Cant beat the HOT cam kit for a nice little NA upgrade on a budget.

JMO tho
Jason

 

Alex, not talking WOT here, just low end stuff. I didn't dyno on a Hotcam, its larger, but I still made good TQ, 325@2500 and 385 peak, without the ignition miss who knows. On the low end though yes, timing magic in the right places really help the car out, probably a good amount of this is not only the cam but the heads.

A non-programmed car with several mods including a set of heads and a larger cam, of course its not going to respond as well as it should, and IMO this is going to be pretty noticeable on the low because of it. More time and difficulty is incurred on low end timing than anything else, at least in my experience. If I was a pro tuner I'm sure someone could be much faster, but to get things PERFECT I expect someone to spend pretty serious time on the car, I did 'good enough' with a tune off the net and some fuel changes with almost nothing done to timing, but to get every stinking ounce out of it, its going to be custom tuning and some time.

Does this make some sense? I think its hard to know just exactly what I mean without the experience itself, just putting the car in gear and it freaking pulled pretty hard with modest fuel input, changing the timing to avoid the ping and I juuuuuust lost some TQ, still very driveable but a noticeable compromise that I wanted to somehow get back. 91 MTBE is not very friendly.

 

Yeah, I understood that you were talking part-throttle, I just mentioned the WOT thing because it sorta shocked me. I can't say for sure if this insensitivity to timing will carry over to low end, part throttle tuning. Also, I know your setup. You are running AI heads with a "CC306ish" cam on a 350. I think you made around 410rwhp, stock bottom end.

I actually don't care about "power" below 1,500, just that is it more driveable. The entire drivetrain will oscillate if I'm not careful and let off the gas under ~1,400 RPM. Keeping the system "loaded" prevents this but requires the thought, which, to me, takes away from the driveabilty.

If I can get a decent fricken laptop, I'll try adding timing in. I think adding timing makes for worse emission numbers though. Maybe I can borrow Christians gas analyzer and make a good balance.

-Alex

 

Ok, here's my question on the HOT cam. Didn't GM design that cam for showroom stock racing? Or, what DID they have in mind when they made that thing? Why do you think they designed it like they did? To make power without compromising mileage too much?

 

it seems to me- and take with a grain of salt- that the hotcam size is fine for a 350.
HOWEVER, I do think it can "optimized."
It has too much exhuast and the lopes aren't steep enough.
This does make for a nice "soft" cam with some grunt behind it.

TO say that you can make better power with some fine tuning is one thing.
To say its too small is another.

I definatly think it needs be matched with a good converter/gears setup though. but then again, what cam doesn't?

 

My experience w/ TPIS is that they are a great company, but their mission is total streetability w/ no noticeable detractions from tip-in. When I built a 355 for my TPI 85 IROC they advised me on cam selection. They assured me that the ZZ9 cam was what I wanted. In reality, I was very underpleased w/ this cam. Yes, my iroc idled @ 700rpms ROCK-steady like it was from the factory and yes, tip-in response was good (even w/ the factory PROM) but it was a dead goat in the upper RPMs. I realize TPI wasn't known for good top end, but a swap to a cam comparable to their ZZ-409 cam that they said was "way too big" gave me everthing I was looking for. Fast forward to my 95Z the first year I had it. TPIS again advised me on a cam, and gave me some accurate numbers. W/ their ZZ9 I could only expect 18rwhp w/ headers, intake and throttle body.....? Now, several years down the road, I've done multiple hotcam installs on factory headed cars. The one person that didn't like the idle was using a stock torque converter against my suggestion. Even he was pleased after using as split combo of 1.6 RRs and 1.5s intake and exhaust to clean up the idle. As for low-end torque, I personally don't need anymore. My Hotcam will blow the tires off wicked-fast w/ my choice of stall. The mid-high power is unbelievable and my track numbers would certainly suggest that the cam-choice was a successful one.
Kudos to the person who brought up that the LT4 hotcam was a show-room stock racing cam. It was designed to work well w/ a stock-headed, stock-manifold M6 car to give it an edge over the competition. Since in a showroom stock style race, you generally try to stay high in the rpms, GM had NO concern w/ lowend street worthiness, they were concerned w/ massive hp and torque improvements from 3,000rpms to 6500.
That article you posted touches on another touchy subject. LT4s made magnificant power on the street but many people found their port-velocity unacceptable. I do agree that for a mildly modifed car, the intake runners are a little on the large side. However, working at a performance shop in the past, we were able to adress this issue by using a smaller throttle-body, and doing some part-throttle tuning.
Don't forget that you can adjust many areas to increase intake velocity. cam timing (I had my hotcam ground w/ an addtional 2.5 degrees of advance), Valve size, rocker ratio, throttle body size, MAF size, exhaust tuning (better scavenging of the cylinder leads to better intake charge), and the list goes on. Also, LT4 heads and intakes fit like $7!T right from the factory. Half the issues I've encountered w/ poor running Lt4s had to do w/ their tendency to form intake leaks.

 

I have pinging with my recently installed cam. (hotcam/ppd heads with 2.00/1.6 int/exh and Slp midlength headers w/chip from pcmforless) Should I send the chip back for retuning. I also have an idle stumble and part throttle stumble.