Aetos

iTrader: (4)

Before people tell me to search, I have and have read tons and tons of pages of information, but never quite understood the reasoning behind people saying low end power wins street races.

My reasoning:

What is the point of low end power during a race when, if you are smart/understand cars, you will down shift into a higher RPM range and benefit your actual power band during a race? Sure, the smaller cams have power under 3k rpm, but honestly, what person intending to win a race goes WOT at 2k rpm, unless you're already in 1st gear where I see the small cam having the only advantage(but 1st gear goes by pretty quick). To reiterate, If you intend to win, you down shift into your power band. So, in what way does the low end power of a small cam come into play during a street race?

I can see the smaller cam being funner low end because of the torque, but aren't most races top end power, not low end grunt? Sure, your car is gonna win the race to the car stopped in traffic 5 feet in front of you, but the bigger cam will win during pretty much any highway roll, right?

Now, the question of drivability arises: From everything I've read from tuners and owners of big cams that actually have first hand experience, drivability of a big cam is all in the tune. If your tune is fine, the drivability of the cam will be fine, you just won't have all that low end power, but that's the nature of the cam. So, the smaller cam isn't that much greater in drivability as long as you have a competent tuner.

Short Version:

Big cams can down shift to get into their power band mooting the point that smaller cams have power quicker. So, whats the point of low end power?


The reason I'm asking is in order to learn more about what build I will be going for in the future. At the moment, after talking with Joey from Tick a bit, I'm highly leaning towards the Polluter with its nice top end and decent low end. Before I spend this much money, I want to coherently see why people advocate smaller cams as dominator's of the street.



Edit: Didn't see a new similar post to mine under this was created while I was writing this one, but its a bit different... SORRY!

DaveX

Your making some very general assumptions and I'm not sure what you are considering big or small. And really there is alot more to it than simply big vs. small and power range. The truth is a well sorted out combo with a "small" cam can out run someone who simply threw in the biggest cam they could find along with a set of headers. Some of these "small" cam combos start pulling hard about 3,000 rpm and make peak power in the 6,200 - 6,500 range, with a desired shift point of about 6,800. IMO this is plenty to throw at the factory bottom end. To get the most out of a "big" cam you will need to twist it a bit higher, which is not a good idea on the factory bottom end. If your going to build a motor to handle it and drag racing is your objective, that changes things. Another issue you mention is driveability. This is a subjective topic. Plenty of people say their big-***-hairy-*****-don't-F-with-me cam drives like stock. While they can be tuned to drive well, they will still drive like a car with a cam in it. Tuners have many tricks. To improve driveability of a cammed A4 car, you pretty much have to raise the TCC lock/unlock speeds if the car has a decent size cam in it. Which solves some issues but at that point it doesn't drive like it did before the cam. And bigger cam = higher stall, not necessarily desirable for a car regularly driven on the street. M6 cars typically have to keep the rpm's a bit higher to avoid the chug-chug affect. You get used to it to a certain degree, but again it's not like it was before the cam. Some are willing to tolerate all of this, and actually prefer it. I did 20 years ago. Now, not so much.

Aetos

iTrader: (4)

What if we look at the "big" cams such as the polluter (24x/24x (.61x"/.61x") which make peek torque at approximately 6.5k rpm or so. Stock blocks can be spun to 6.5k all day long, no? Wouldn't a correctly specced Head/big cam combo beat a correctly specced head/small cam build? They will both pull hard, the smaller cam will pull stronger in the low end, but the bigger cam will tend to make better high end numbers where the cars stay for most of the race leading to the big cam to win?

From what I've witnessed on the forum, most people that say big cams are not for DD tend to be people that have never owned a big cam and went straight to a small cam. This isn't always truth, but thats what the common trend on ls1tech is. While, most tuners and actual owners of big cams say drivability is pretty good with a good tune.

DaveX

Stock bottom end can handle 6.5 ok. But I think you would really need to twist it a bit higher to get the most out of that cam. Just keep in mind the more time it spends up there the quicker it wears out. But in general yes, a larger cam with a matched set of heads should win the drag race all else being equal. If this is your only objective then that is the route you should go. The thing is, everyone has different goals and tolerance levels with respect to driveability. What one guy considers acceptable may not be the same for the next guy. So you really won't know what your getting into until you go there unless you know someone with a similar combo that will let you drive their car.

Johnnystock

iTrader: (6)

And theres the drivetrain too that comes into play. Heres an exemple: you do a roll side by side(having big cam with 3:42) with someone(given the same ls1 car) with a smaller cam and same gear, he'll be in his powerband sooner and longer than the big stick guy.

BUT, if youre well geared, stalled and in your powerband, I say the big stick should win. Of course 7000rpm is harder on the valvetrain and engine than 6000-6500rpm too.

Its all about getting the right combo. Peak power isnt always everything. For an all out drag car, its nice, but for a street car, you might look for a car that has something something better under 5000rpm.

Believe me, I'm in the same boat as you; I'm really appealed by peak hp, but I have to be realistic; my car wont see drag race too much and I'm 3:42 and I have an LS6 intake..A smaller cam is more suited for me. But since I already have 22x duration cam, I'll switch for 233/239 style cam or Torquer 3...I looked at the power curve and its good from 3000-3500 to 6500-6800. Torque is a lot better than big stick down low.

Johnnystock

iTrader: (6)

Problem is that you dont shift at peak torque, you shift at peak hp that should be 6800-7000...

RyderTA

iTrader: (3)

Johnny you consider a small cam the torquer 3 or 233/239? Those are some fairly big cams IMO, I would concider my T2 somewhere inbetween a big cam and small and it has good drivability. Sometimes I wish it had more low end but the high end makes up for it.

Aetos

iTrader: (4)

Actually.. looking at the dyno graph of the polluter it's peak hp is close to around 6500 or so

http://www.tick-performance.com/cata...ollutercam.jpg

Shouldn't you get a bigger gear on a big cam anyway? Most m6 guys go 4.11s anyway, meaning you should reach your power band quicker anyway. The thing is, you're not stuck at one rpm with cars... if you're not in your power band, shift into it which is possible on most races(unless you're going from a dig). The smaller cam will have lower end power, but that only comes into play for the first moments of the race if you go from very low speed. Will that difference in the first few moments in 1st gear make up for the power difference where you will spend most of the race? I don't see big cams just for drag cars. Even street cars who usually race from a roll. Roll races usually make you down shift usually into second, sometimes first, which will put you way up in the power band again making the low end power of smaller cams moot. The only upside to the power of small cams that I can witness is if you go from a dig in the street where you can't get good traction launching from high RPM.

Also, why wouldn't you already be in your power band if you're racing from a roll?

Also, I love the thumping idle sound of a big cam car...

EDIT: Wouldn't big cams be better for bad weather traction also? (rain/snow). They will barely making any power under 2k rpm meaning you shouldn't have any major traction issues, correct?

Johnnystock

iTrader: (6)

At a given speed, each car his in the same RPM(unless gears) and so youre not in the same powerband with a big cam compare to a small cam..That was my point. No I dont want to invest on that crappy rear end; next time it blows(4th time) I'm going 9inch. And I dont like big gears since its 99% street driven.

No I dont consider T3 or T2 small cams, but i consider my 22x cam small. The powerband is really nice though while top hp is not setting any record. So thats why I want to go bigger, not the biggest, even if its really tempting.

Gotta admit theres a lot of big badass cam outhere, like the polluter.

Johnnystock

iTrader: (6)

My SS never sees rain or snow!!

01ssreda4

iTrader: (96)

i have ridden in futral f cam (the 232 one w a 430 rear) and its a joke leaving a gear at 3k doing a roll punch, it built steam by 4k and was finally booking it at 5k. the torquer v3 (3.73 rear) i rode in had great power above 3500, it ******* screamed, but was a dog below that. my 224 has excellent midrange and top end but pulls very even. its torquey down low and doesn't fall off up top until the 6200 shift point. i dont really know under 3k bc of my stall. the 224 is a fun cam w a 3200 stall bc you dont have to find your gear and wind your motor out to get your car moving, it will pull anytime any gear it doesn't matter. thats very useful on the street. it can pull through the gear without downshifting. i also have heard that a 228 vs a 224 is only worth about 8-10 peak hp.

Aetos

iTrader: (4)

I'm not talking about a 228vs a 224 though.. I'm talking 228 or 224 vs like a 23x or 24x. The torquer 3 was a dog down low, but does it really matter was sort of power you have down low, not like you're gonna try to race anybody in low RPM, unless you wanna lose the race or its ricer you're joking with. What pulled harder top end, your torquer 3 or your 224? Which do you think would win a race during a highway roll where you can down shift to a big cams sweet spot? Theres also bigger cams than the torquer 3 which will probably pull even stronger on top end.

My final point that I'm trying to make is: Whats the point of power down low when most races take place in the higher rpm range unless you have some sort of 2k-4k shift clubs that I don't know about. Sure, you probably will get the hop off of the line or jump on a car with a big cam if shooting from a very slow roll where down shifting is not possible, but won't the big cam pull you in after its constantly in its train wreck power zone?

Thats true, but if you have a big cam you won't drive or spec you car similar to somebody that has a smaller cam. You want to be able to hit higher RPMs quicker hence bigger gearing and you will want to down shift into a higher rpm range whenever possible(which the small cam should be doing as well) so this point is really moot. You can't take 2 cars with 3.42 gears and give one a big cam and one a small cam and tell them race. You're gonna spec the car to what it needs. Big cam = big gear to reach higher RPMs quicker.

00T/AWS6

iTrader: (17)

I was in the same situation as you. I not to long ago put a cam in my car and was thinking the same thing, why put a smaller cam in your car when in racing your car is always high in the powerband. Everyone always says it's better for street and I only thought it could be better on the strip becase you will have instant power down low.

Obviously I went with a mild cam ~230/238, I shift at like 6500 redline at 6800 so still good top end power and doesn't spin to 7k. I never understood the small cam theory nor have I driven a small cam car. I think 230+ is the only way to go. Can't wait to get some 4.11's to really open this cam up and then 92/92/TFS 215's. Goodluck!!

Aetos

iTrader: (4)

Finally, another person that understands my conception of this big cam vs small cam business. Hopefully some smarter technical people with actual first hand experience can chime in on this whole argument(like performance shops).

bongva

iTrader: (7)

some good info here

01ssreda4

iTrader: (96)

well my shift points are 6200 so a cam that peaks 1 rpm higher then that is pointless. the torquer V3 and the futral i spoke of earlier were in 6 speed cars. my 224 is in a stalled car. i would chew both of them up off the line and then it would only be a matter of how long would it take them to catch me. length of the race determines the winner. i believe the 230+ cams dont even match factory torque numbers until over 4k rpms and honestly most cars dont spend most of their time over 4k. there is no one size fits all and nobody is right or wrong.

1997bird

iTrader: (2)

This is why you should run a custom grind cam, that way all of your parts work together and with each individuals driving style.

Sorry, I just found this statement funny as hell. Too bad you haven't rode in a car with matching components, I think that you would change your mind about this statement.

Johnnystock

iTrader: (6)

What I'm trying to say is maybe not everyone has the chance, the skills or the will to setup a the whole car in a perfect match of parts in one shot. You work your way up there slowly; thats why sometime you end up with a big cam and you have to wait the next year for a built rear end. But, you can still enjoy the 5000-6800 pull while waiting..

Depends on what you do with the car; If you DD it, its different than a weekend warrior. A car in town will spend most of its time under 3500rpm, not saying thats a disaster to drive a MS3 sized cam(in fact I wouldnt care) in those rpm, but you have to think about it a bit before going with it. My car rarely sees more than 2000rpm, and it still has very good street manner with my small cam.

You have to wish your tune and your car will work together well.

WeathermanShawn

iTrader: (1)

Given identical weight, gearing, and aerodynamic drag, the car that produces the greatest average HP throughout the power band will accelerate the fastest.

If you are talking about WOT racing that power band (M6) is the rpm range that occurs after each shift..~ 4400-6600+ rpm(s).

If that rpm range is your total interest, pick a cam with an IVC of ~44-48 IVC.

Yes, a bigger cam (duration) will have a later IVC. With the right combination of intake manifold, heads, and exhaust you can take full advantage of the later IVC.

It is just a point of diminishing returns. Some 224 cams may produce the same average HP as a bigger cam, depending of the entire setup. Most likely though the 230x range is what you are looking at.

Your question will always elicit a lot of debate. In todays world the type of rpm's and the resulting speed you are at, is only safely done at a track. Most people simply do not hit that rpm range in daily driving or in 'spirited' street driving.

But, the answer to your specific question is to find the latest IVC (greater duration) cam that can produce the greatest average HP in that specific higher rpm range.

Good luck.

..WeathermanShawn..

Aetos

iTrader: (4)

When you're out for a spirited drive and/or racing though won't 95% of your time be spent in the upper rpms 4k+ where the bigcam makes better average torque/horsepower than the smaller cam? I don't see the point in having power down low when the only time you are constantly down low is when driving regularly and commuting from one location to the other.

They may produce the same average HP when taking into consideration the whole RPM band, but when driving aggressively most of the time you will be in higher rpm range where the big cam will outdo smaller cams.

As I will state underneath, I'm pretty sure most people on these forums and most people that own "fast"(whether they really are fast or people think they're fast) will spend time in the upper RPM range on the streets even if it may not be totally "safe". If you're not driving fast for fun or for racing I don't see the need for the power down low.

The only time you really need power is when you're racing and/or driving very spirited for fun. If you're racing and or driving for fun and you're constantly under 4k you're doing something wrong and you will lose. I'm sorry, but if you're racing you're well over the 4k range constantly, except for the 1st 1-2 seconds when you're down shifting. You're correct in saying you will mostly be under 4k, but that is under regular driving conditions when you don't NEED the power until you start racing when you will almost always be over 4k rpm where the big cam shines.