camshafts
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430 Posts
you never interchange cams into differnent engines unless the timing is exactly the same.
you'll end up bending all your valves. and maybe have detonation.
you'll end up bending all your valves. and maybe have detonation.
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70 Posts
Your camshaft choice depends on the type of perofmance you're lookinf for. What RPM range are you looking to operate in, and where on the RPM curve do you want your HP and Torque? A more racy camshaft will generally raise your redline and cause you to have a decrease in low end torque, while increasing overall performance at higher RPM's. This is good for on-track performance and drag racing, but this could hurt your overall driveability when driving on the streets.
race camshafts, (Or any cam with a hot lopey profile) will cause the car to have a rougher idle (Even force you to raise the idle to as much as 1200 RPM or more). You cash in on the benefits when you get the motor wound up on the tach. The improvement is greater throttle response, more high end HP and a broader torque curve at higher revs. You will probably want to avance the timing a couple degrees too to offset the cam.
As with any cam swap, you're going to want to check and be sure that the springs on your existing valves are going to be adequate for the camshaft you're using. If they ware too weak and you're cam has a very aggerssive profile, the springs may not be able to fully close the valves in time and you may notice that you're not getting good compression at higher RPM's, or even worse, you may destroy your engine if the piston comes up on an open valve. Over time your springs may fail completely resulting in a loss of power and a huge repair bill to reove the top end and replace the springs and retainers.
race camshafts, (Or any cam with a hot lopey profile) will cause the car to have a rougher idle (Even force you to raise the idle to as much as 1200 RPM or more). You cash in on the benefits when you get the motor wound up on the tach. The improvement is greater throttle response, more high end HP and a broader torque curve at higher revs. You will probably want to avance the timing a couple degrees too to offset the cam.
As with any cam swap, you're going to want to check and be sure that the springs on your existing valves are going to be adequate for the camshaft you're using. If they ware too weak and you're cam has a very aggerssive profile, the springs may not be able to fully close the valves in time and you may notice that you're not getting good compression at higher RPM's, or even worse, you may destroy your engine if the piston comes up on an open valve. Over time your springs may fail completely resulting in a loss of power and a huge repair bill to reove the top end and replace the springs and retainers.
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430 Posts
hmm, was thinking he meant changing cams from different engines..
performance cams can be put on, yeah. but i wouldn't do it til the rest of your engine is up to speed.
Variable Valve Timing is made for one thing... having speed at low end and high end.. or low and mid... or mid and high....
tells you exactly what cams are for... power at particular points of your power curve. but for you to really benefit from racing cams... it'd be nice to have a bored block that will accept the added fuel and air and exhaust.
just never saw a point to spending that much, before you play with the block. more power comes from the block for your money. but when you play with that, you gotta play with the whole system. but that's how you make a badass engine. from the block
could be why most engines you find in yard are junk now...cuz effers just throw on turbo and cams and blow it up.
performance cams can be put on, yeah. but i wouldn't do it til the rest of your engine is up to speed.
Variable Valve Timing is made for one thing... having speed at low end and high end.. or low and mid... or mid and high....
tells you exactly what cams are for... power at particular points of your power curve. but for you to really benefit from racing cams... it'd be nice to have a bored block that will accept the added fuel and air and exhaust.
just never saw a point to spending that much, before you play with the block. more power comes from the block for your money. but when you play with that, you gotta play with the whole system. but that's how you make a badass engine. from the block
could be why most engines you find in yard are junk now...cuz effers just throw on turbo and cams and blow it up.
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70 Posts
Agreed. And that is one thing I forgot to mention...
If you have modified cams in anything with variable valve timing you run an increased risk (I say increased because the risk was always there to begin with) of causing internal engine damage during hard deceleration (Especially in manual transmission cars). The reason is because the engine slows down faster than the camshafts can alter their position, causing valve / piston contact. This risk is most common in older cars and engines with early VVT systems, but the condition is more likely to happen with longer duration/higher lift camshafts.
If you have modified cams in anything with variable valve timing you run an increased risk (I say increased because the risk was always there to begin with) of causing internal engine damage during hard deceleration (Especially in manual transmission cars). The reason is because the engine slows down faster than the camshafts can alter their position, causing valve / piston contact. This risk is most common in older cars and engines with early VVT systems, but the condition is more likely to happen with longer duration/higher lift camshafts.
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784 Posts
. only sr20's with VVT are the s14 and s15 SR20DE LEV's, and the SR20VE with the Neo VVL system.
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430 Posts
exactly why ppl are afraid of it...
but that's like saying "i'll stick to my horse... it more reliable... even though it'll die sooner than a car"
..get this.... ;]
....
..*building up for something that's been in his head and not too sure if he should put out there cuz then he'd be losing money and business later, but since he's a poor boy and this is a small forum...*....not too mention some egghead in a small white room already made minimum wage off it to a corp.
...tapered cam lobe deceleration edges that allow you to stop the car just as fast as any other stationary cam lobe.
;]
i hate being poor... as business savvy i am, i should be rich. ...too bad i can't keep my foot off the gas pedal and so.... i'm still poor.
f^ckin facist government... ha... *drunk again... ignore me... but not really*
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430 Posts
course... the simple way...
piston valve reliefs.
...but that changes comp ratios when you're try to keep the combustion chamber nicely mixed
but mentally, i can't picture a sure bet way of two different cam lobes QUICKLY changing out..
cept...
and yes, this sound sci-fi, but so did DOHC at one point...
a moving cam.
a full 3 demension (the cam lobe demensions) taper.
one that is tied into the throttle...
giving maximum perfomance in the Intake and Exhaust during each ECU calculated rpm
piston valve reliefs.
...but that changes comp ratios when you're try to keep the combustion chamber nicely mixed
but mentally, i can't picture a sure bet way of two different cam lobes QUICKLY changing out..
cept...
and yes, this sound sci-fi, but so did DOHC at one point...
a moving cam.
a full 3 demension (the cam lobe demensions) taper.
one that is tied into the throttle...
giving maximum perfomance in the Intake and Exhaust during each ECU calculated rpm
Joined
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430 Posts
thing is....
;]
can't say...
but in the end, you get it to work.. and you have an engine that will have high gasmilage and high performance for each friggen rpm.
;]
can't say...
but in the end, you get it to work.. and you have an engine that will have high gasmilage and high performance for each friggen rpm.
Joined
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430 Posts
BUT!
take a look on YouTube...
Coates Valve Train
;]
no oil
no cam linkage
60% more efficient.
and the kicker...
easily revved up to 15,000RPMS!!!
take a look on YouTube...
Coates Valve Train
;]
no oil
no cam linkage
60% more efficient.
and the kicker...
easily revved up to 15,000RPMS!!!
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