pros and cons of aftermarket cams?

evil04svtcobra

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i know it sounds awesome, but seems like little hp gains from aftermarket cams...

just wondering some pros and cons of changing cams?
 

fr03cobra

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if you do it your self just the price of cams. if not about 1k to install. for 30hp. your call
 

DarkSnake

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Custom grinds can help a lot if you are willing to up your boost. at 19 psi you are leaving a lot on the table. You can probably add 100 rwhp with custom grind cams and 26 psi boost.
 
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04sleeper

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A friend of mine bought some just for the sound. He has a Whipple 3.4 and stock ported heads.

He bought the Crane stage 2 kit. After 1000 miles a retainer broke and it took out the whole motor.

He found out that the springs that come with the kit were very poor and thats why it dropped a valve.

He only picked up like 30 HP running the Whipple 3.4 @ 21 psi.

For 30 HP and a chance of dropping a valve, I'll keep the stockers.
 

04cobra13

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A friend of mine bought some just for the sound. He has a Whipple 3.4 and stock ported heads.

He bought the Crane stage 2 kit. After 1000 miles a retainer broke and it took out the whole motor.

He found out that the springs that come with the kit were very poor and thats why it dropped a valve.

He only picked up like 30 HP running the Whipple 3.4 @ 21 psi.

For 30 HP and a chance of dropping a valve, I'll keep the stockers.

Damn really? That makes me sacred of getting aftermarket cams now..:??:
 

PistolWhip

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It's all about usable power under the curve. Most of the time in these cars, cams don't produce staggering peak RWHP increases, but they can absolutely increase power over the entire power ban.
When you think about it, 4 valves at the top of a 3.55" bore allows for allot of room for air to get in and get out. With that in mind, if you can maximize the combinations efficiency further by adding a custom cam profile that not only increases power under the entire curve, but also puts the curves peak at a more usable spot in the RPM range, does it really matter that the end result was "only" a 30 RWHP peak increase?
Cams are not for everyone and I will admit, most of the common combos (including mine) found in Terminators have very acceptable power curves without a custom cam profile, but if I was trying to extraxt every last bit of performance from my combo (notice I said performance and not peak power), cams would be my next mod and long tubes would be right behind them in line.
Ultimately the only person that can make the call as to whether the power to investment ratio is worth it, is the person spending the money. The one thing you can be sure of though, is even if you don't get the peak # your hoping for, you will no doubt have a BAD ASS sounding car ;-)
 
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virginiafiveo

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cams are the last thing I will do. I'm at 684 with a whipple 2.3L stock shortblock with 80k on the clock roughly. custom cams might yield me a significant gain. but unless your over 500, I wouldn't mess with them. also...if your over 500....do them either WITH long tubes, or install your longtubes first. I don't know what mods you have done....but I would think about it long and hard. if you do it. custom grinds only. and remember you get what you pay for....so don't skimp.
 

04sleeper

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I always say that unless you are racing a specific class, like in NMRA or something, where you have to get every last bit of power out of a combo, then leave the stockers in. The power you gain can easily be made up in other areas.
 

evil04svtcobra

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cams are the last thing I will do. I'm at 684 with a whipple 2.3L stock shortblock with 80k on the clock roughly. custom cams might yield me a significant gain. but unless your over 500, I wouldn't mess with them. also...if your over 500....do them either WITH long tubes, or install your longtubes first. I don't know what mods you have done....but I would think about it long and hard. if you do it. custom grinds only. and remember you get what you pay for....so don't skimp.

i have slp long tube headers... i make 635 at 6400 rpm's... with different cams will you be able to up the peak rpm's?
 

EvilTwins

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I just wish there wasn't so much hearsay and guess work when it came to aftermarket cams!!

I might just go with some Ford GT cams for my build because I at least know I can rely on their build quality. Good way to pick up some extra lift I guess so they should help with my ported heads...

Oh and a big :nonono: to people that want cams just for the sound. Spend your money for performance and not to be a domestic ricer. I actually like having a smooth idle!!
 

virginiafiveo

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cams can help the overall redline, but EVERYTHING needs to be capable of higher RPMs PM NAZMAN. he's had several NA and FI cars that go 8000 RPM redline. if your going to do cams, get a reputible person to port your heads out nicely, then get yourself some better springs and I'm thinking GT cams or possibly the FR500. just how much are you planning on bumping up the RPM. I think the stock engine itself in an 03 is capable of 7000 RPM...it's the blower holding it back. but seeing as you have a twin screw based on your stated power level. I'm going to say talk to your tuner about the max RPM your current engine can withstand.
 

ramairfreak98ss

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when you switch to aftermarket cams, how much lift is there compared to stock?

Im not too familiar with the 4v cobra cams... i only know on the GM stuff ive messed with, our GTPs go from like a .470 lift stock 'baby cam" to even our state 1 s are .510, stage 1x which is most common is .520, stage 2 like in my 99 are .536 which is still sort of small.

The burbling sounding c6s, c5s, gtos and other LSx cars go from .500s to .600s and thats considered semi-aggressive.

Are the stock svt cams that aggressive already? I cant see how a stock cammed cobra can make 600rwhp with any kb or whipple, and then only do 30whp more, sound like an older 5.0L v8 cammed and not crank out dishloads more balls?

If you on stock manifolds/stock cam with a 19psi whipple, go to headers and drop to say 16-17psi, get cams, drop another 1-3psi, your now dropping blower pulleys again to get back to at least the 19psi and now can probably run 21-23psi on the street

I know they say our GTP aftermarket cams are only about 30whp difference from a very aggressive, car hardly starts .600 lift stage 4 cam to a stage 1x thats in my silver 2001. but without the cam, we'd be stuck at much lower boost levels, make far less power etc and thats only a 6 cyl.
 

PistolWhip

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Lift has nothing to do with the aggressive idle you get from a set of cams (or a single cam in a pushrod engine). The aggressive idle is caused by the cams lobe separation profile. Lobe separation and centerline have to do with the valve timing in relation to the rotation of the crank. Lobe separation angle is basically a measurement of the peak opening points between the intake and exhaust valves. In most cases when you decrease the degree of lobe separation, the idle sound becomes more and more aggressive.
Lift is only a small part of the puzzle when choosing a cam. You also need to factor in valve duration which is just as important in choosing the right cam as overall lift.
You can increase power without changing the power band of the engine by increasing lift but maintaining the same duration. However you can't just keep increasing lift because eventually you'll create piston to valve clearance issues. This is the reason that most engines don't get a whole lot of peak power out of cams with 4.6 DOHC engines. The piston to valve clearance is already pretty close and there isn't a whole lot of room to increase lift without adding valve reliefs to the pistons.
Now the duration refers to how long the valve is kept open. Longer duration will usually move your peak power points higher into the RPM band while shorter duration will do the opposite. However, there's a trade off in low end torque with either scenario. The later increasing the low-end torque while the longer duration will decrease low-end torque. Measuring duration at a specific point in the cams rotation is another way of getting a true duration measurement since all manufacturers measure their "advertised duration" profile at a different starting and stopping point in the cams rotation. That's why you always see an added duration measurement on a cam card that says "duration @ .050." While advertised duration can be measured using different starting and stopping points, duration at .050" is always measured from the same points so it can give you a more realistic measurement of the cams duration profile.
 
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PistolWhip

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What allot of people don't realize is that when you increase duration and add a slight valve overlap (overlap is when the intake and exhaust valves are open at the same time, which is basically another way of describing lobe separation), you can drastically decrease cylinder pressure. This decrease is usually mostly realized at lower RPM levels.
A supercharger makes power because it forces the engine to ingest more oxygen thus increasing cylinder pressure. So, if you tune for that lower cylinder pressure, you can move more air by raising the amount that the blower forces into the engine. If a cam profile causes boost levels to drop, that doesn’t mean that it caused the engine to move less air, it just means that the engine is experiencing less pressure in conjunction with that amount of air. Boost is a measurement of pressure but power is a measurement of efficiency and since an internal combustion engine is basically nothing but a big air pump, the more are you can get it to move, the more efficient it is and the more power it can output. That's why I always say that peak RWHP numbers are not always the best way to measure the effectiveness of cams (or any modification for that matter). If the cam allows you to increase the volume of air that is pumped in and out of the engine without drastically raising cylinder pressure, it's done its job.

The amount of lift is just a small part of the equation and in most cases valve spring coil bind and piston to valve clearances will dictate your max lift potential in an otherwise stock engine, thus limiting your ability to increase power without a completely custom cam profile that can take advantage of duration, lobe separation and lift all together.

It can all be confusing, but if you break it down like I did with the pump reference, it makes it much clearer. Clear as muddy water right ;-)
 

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