Camshaft Discussion Thread
02-Apr-2007, 04:00 PM
#1
Senior Member
Thread Starter
Join Date: May 2003
Location: Ontario
Posts: 18,367
Camshaft Discussion Thread
This is a camshaft discussion thread. Please post your thoughts and experience with certain branding, specifications and tuning method. Moreover, there are bound to be various opinions and any personal attacks, or belittling posts will get deleted.
Let’s share our knowledge, in a sophisticated way.
Let’s share our knowledge, in a sophisticated way.
02-Apr-2007, 06:00 PM
#2
Registered User
Join Date: Mar 2007
Posts: 532
Alright I'll get this started I have Cat Cams which I really like. I believe they are stage 2 the product code is 2501605. The only thing that sucks was JRP told me the springs and retainers weren't needed.. I talked to a few people with them and they said after I awhile they lost power with the stock valvetrain... lying bastards. So I bought some Cat Cams springs and retainers and it should be good once they go in to avoid valve float and that ****. I'm new to this tuning with adjustable cam gears but I think they recommend 4 degrees advanced with the intake cam and 2 degrees retarded with the exhaust cam. Oo yeah the cam gears I have are BDL.
Right now I love the camshafts and I can notice a huge difference but I try not to drive it hard until I get my valvetrain installed. My engine is a b16!
Comments on what you thinK!
Right now I love the camshafts and I can notice a huge difference but I try not to drive it hard until I get my valvetrain installed. My engine is a b16!
Comments on what you thinK!
03-Apr-2007, 01:27 AM
#5
i wouldn't dare use stage 2 cams without changing the valve springs and retainers...thats asking for bad news....and i wouldn't dare drive the car untuned with different cams either.
The only way to know what settings are best for a specific set of cams is to either degree the cams to the manufacturers specs or tune them on a dyno.
I'm personally using crane stage 2 cams, crane dual valve springs and titanium retainers along with ferria valve locks and venom adjustable cam gears....honestly, they're too much cam for a b16, but i got a smoking deal on the stuff brand new ($950 for the cams/valvetrain) so i figured why not, i knew i'd be upgrading to a 1.8L or 2L bottom end anyways.
The difference with these cams is night and day. The midrange is awesome, it has a smooth idle (i've heard a lot of people having problems with these cams not idling so hot) and vtec hits hard at 6k (dyno proven to be the best spot for the vtec crossover).
I however haven't had a chance to fully tune my engine on the dyno, but hopefully i'll be going back soon to finish tuning it, i haven't even started to mess with the cam gears (on the dyno at least).
I personally am a big fan of ITR cams in b16s and GSRs, even in stock(ish) b20vtecs they're a good choice IMO. I actually tuned a car tonight (poor mans type R with b16 pistons) that had ITR cams and again i was impressed. The midrange was phenominal.
I don't get why people would toss a big set of cams in a relatively stock engine and expect good results.
In order for stage 2/3/4 cams to be efficient the head has to have work done to it. Such as different valve springs/retainers (if using anything other than ITR/CTR/stage 1 cams), higher compression (theres no point in having higher lift/more duration if the engine can't flow enough CFM), port and polish, a decent valve job and all of the bolt-ons (or at least an intake, header and exhaust).
I've tuned a b20vtec with stage 1 or 2 cat cams and i was less than impressed, this was b/c they were too big of a cam for the setup, low compression, no headwork, stock exhaust and exhaust manifold. I personally think that stock b16/GSR/ITR cams would've been better for this setup.
If anyone is really interested in getting some cams i'd seriously consider checking out UGR (under ground racing), they make direct copys of all of the popular cams for a very reasonable price.
Or you could always go with the ever so popular and proven time and time again skunk2 stage 2s or JunIII's.
The only way to know what settings are best for a specific set of cams is to either degree the cams to the manufacturers specs or tune them on a dyno.
I'm personally using crane stage 2 cams, crane dual valve springs and titanium retainers along with ferria valve locks and venom adjustable cam gears....honestly, they're too much cam for a b16, but i got a smoking deal on the stuff brand new ($950 for the cams/valvetrain) so i figured why not, i knew i'd be upgrading to a 1.8L or 2L bottom end anyways.
The difference with these cams is night and day. The midrange is awesome, it has a smooth idle (i've heard a lot of people having problems with these cams not idling so hot) and vtec hits hard at 6k (dyno proven to be the best spot for the vtec crossover).
I however haven't had a chance to fully tune my engine on the dyno, but hopefully i'll be going back soon to finish tuning it, i haven't even started to mess with the cam gears (on the dyno at least).
I personally am a big fan of ITR cams in b16s and GSRs, even in stock(ish) b20vtecs they're a good choice IMO. I actually tuned a car tonight (poor mans type R with b16 pistons) that had ITR cams and again i was impressed. The midrange was phenominal.
I don't get why people would toss a big set of cams in a relatively stock engine and expect good results.
In order for stage 2/3/4 cams to be efficient the head has to have work done to it. Such as different valve springs/retainers (if using anything other than ITR/CTR/stage 1 cams), higher compression (theres no point in having higher lift/more duration if the engine can't flow enough CFM), port and polish, a decent valve job and all of the bolt-ons (or at least an intake, header and exhaust).
I've tuned a b20vtec with stage 1 or 2 cat cams and i was less than impressed, this was b/c they were too big of a cam for the setup, low compression, no headwork, stock exhaust and exhaust manifold. I personally think that stock b16/GSR/ITR cams would've been better for this setup.
If anyone is really interested in getting some cams i'd seriously consider checking out UGR (under ground racing), they make direct copys of all of the popular cams for a very reasonable price.
Or you could always go with the ever so popular and proven time and time again skunk2 stage 2s or JunIII's.
03-Apr-2007, 07:22 AM
#7
Senior Member
Join Date: Jun 2005
Location: At your moms
Posts: 2,633
funny, people use to freak when i said i was running 13:1 compresion on the street, now it would seem that people are pushing the compression to that range on the street. its one of the ways to get big cams to work through out the whole rpm range...my engine made 140wtqfrom 2000rpm and then at 4600rpm it jumped to 160wtq till about 8000rpm....and my torque curve was pretty much flat...i like the Endyn "bump stix" as far as cams go and i wish i had them in my engine...
03-Apr-2007, 10:29 AM
#9
Registered User
Join Date: Mar 2007
Posts: 532
well I am also not a mechanic so I didn't know. I am still learning a lot. I paid only 700 in total for my cat cams, valves and retainers all brand new. I am getting my head work done at the end of the month. It will include shavin the head valve angle job and maybe a p & p.
03-Apr-2007, 03:04 PM
#12
Senior Member
Thread Starter
Join Date: May 2003
Location: Ontario
Posts: 18,367
Originally posted by LEITNER
on the port be carefull...a head can become garbage quicker than it can become a jewel...watch who you take it to...i can only think of 2 places that i would even consider going too in the gta...
on the port be carefull...a head can become garbage quicker than it can become a jewel...watch who you take it to...i can only think of 2 places that i would even consider going too in the gta...
03-Apr-2007, 08:12 PM
#16
Registered User
Join Date: Apr 2006
Posts: 261
I think the whole dynamic and static compression is coming up ....you coudl run 13:1 cause you had huge cams which would in baisc terms bleed off some compression
if I remember correctly from my theory short stroke b16 = lower dynamic compressoin that longer stroke b18 ..? correct? which is why big cams don't fare well in the b16 and over camming is a issue. It seems like the guy's who over cam a setup are the ones making low numbers or big "peak" with no curve. You need the whole package compression head flow and cams
if I remember correctly from my theory short stroke b16 = lower dynamic compressoin that longer stroke b18 ..? correct? which is why big cams don't fare well in the b16 and over camming is a issue. It seems like the guy's who over cam a setup are the ones making low numbers or big "peak" with no curve. You need the whole package compression head flow and cams
04-Apr-2007, 04:18 PM
#17
Registered User
Join Date: May 2005
Location: Vancouver
Posts: 180
I just picked up a set of Toda B's.
I'm currently going to go all Toda in terms of valvetrain:
Toda Valvesprings, Toda retainers (if they still make them), Toda timing belt, Toda cam gears, and most likely Hondata S100.
I may leave the compression alone, but i'm debating a thin metal headgasket to bump it up a bit.
hope to get some dyno tuning on these cams so i'll post up once i get results. I've been told they're great for mid-range power.
I'm currently going to go all Toda in terms of valvetrain:
Toda Valvesprings, Toda retainers (if they still make them), Toda timing belt, Toda cam gears, and most likely Hondata S100.
I may leave the compression alone, but i'm debating a thin metal headgasket to bump it up a bit.
hope to get some dyno tuning on these cams so i'll post up once i get results. I've been told they're great for mid-range power.
04-Apr-2007, 06:57 PM
#18
fack... ok first of all this thread sucks right now. let's get some real info here that people can use.
to be of any real use, we need to explain first of all what a camshaft is, what it does, how it works...
some definitions so we're all on the same page... duration is how long the lift is, lift is how high the lobe is, the lobe is the 'bump' on the cam, overlap is how long the intake and exhaust valves are both open... lemme know if anyone wants to correct or better explain any of these.
to simplify I'm gonna start with a SOHC cam... it's one cam, carries lobes for both intake and exhaust valves. the profile of the lobe is like an egg shape if you will... and egg has a round bottom part (this is where the valve is closed) and like a pointy top part (where the valve is open)... the shape of this pointy top part determines duration and lift... overlap is determined by duration and the relationship of one lobe to the other (exhaust and intake lobes). so anyways, where was I.... oh yeah SOHC cam, ok it's got 4 lobes for each cylinder, for a total of 16 valves. two intake, and two exhaust valves. when cyl 1 is at top dead center, the valves are closed, and cylinder 3 is also at the top of it's travel, except cyl one is in the compression stroke, and cylinder 3 I think is at the end of it's exhaust stroke, the next time cyl 3 comes down it'll be sucking in an intake charge... the firing order is 1-3-4-2. ok, so everyone got this... 1 and 3 are up together, 2 and 4 are down together. so the camshaft is spinning in a 1:2 ratio to the crank, like you turn the crank 180 degrees, the camshaft turns 90 degrees... everyone with me so far? so... on the cam, the lobes for cyl 1 and 3 are offset by 90 degrees, that's why when you do a lash adjustment you follow the firing order. yes? yes.
ok, so these camshafts dictate the timing, lift, and duration of the lift event for the valves... the basically open and close the valves. the opening and closing of the valves affects many many many things in the engine, from emissions, vacuum, idle quality, scavenging effect, and finally and most importantly to us... volumetric efficiency. the engine is sucking in fuel/air and pushing out exhaust gasses past these valves... the easier we make it for the engine to do this, the better power we get (simple explanation, I could make it more complicated but there is no need). that's why a cam is so important and why there is so much discussion about them. that's also why a cam is useless w/o tuning... if you can't compensate for the increase in volumetric efficiency, you've done nothing. also, this is why you gotta also make sure you've removed all other restrictions that can cause pumping losses like better filter/intake, header and exhaust.
now, the valves and pistons are real close neighbours, you give the valve too much lift and it'll hit the piston, so when building an engine, that's why you gotta clay the pistons with the head installed and the correct cam you plan to use. also, at really high speed, you gotta remember these valves weigh... and weight and speed equal momentum (thanks Sir Isaac Newton), basically what goes up must come down... that's what the spring is there for... too heavy a valve, too much rpm, too long a duration etc.... valve float occurs, and the piston goes smash to the valve. not good. so, big cam and high rpm, you want lightweight components... light valves (maybe even machined stems), light retainers, stiffer springs, etc...
now DOHC, the intake and exhaust cams are separate, so you can affect cam timing and overlap by using adjustable cam gears... that's why DOHC engines make a lil extra power, the events are better timed, even though there are parasitic losses (very slight BTW) from having ONE more rotational assembly.
now, add VTEC to this, VTEC is just a way to affect geometry of how the camshaft acts on the valves, thereby changing the timing on it. VTEC is a whole other beast, you can do a search or read up on temple of vtec or something... it's well documented for even a basic level of understanding, all the way to a very advanced level.
anyways, I just covered this real quick and fast off the top of my head, if there are any corrections, additions, etc.... feel free to toss it out there plz. I just thought I'd bring the n00bs up to par so they can read with intelligence.
also, I don't wanna hear all this isht about Skunk 2 this or Blox that or CompCams such and such. cut that noise! I wanna hear the specs on the bitsh, lift, duration, overlap... what are the actual specs, why did you choose those specs, what do you believe they will in theory do for your volumetic efficiency. I personally dunno much more about this... the book someone (
you know who you are, lover 
) lent me had all this info but I failed to read it in a timely fashion so I remain in the dark as of now.
to be of any real use, we need to explain first of all what a camshaft is, what it does, how it works...
some definitions so we're all on the same page... duration is how long the lift is, lift is how high the lobe is, the lobe is the 'bump' on the cam, overlap is how long the intake and exhaust valves are both open... lemme know if anyone wants to correct or better explain any of these.
to simplify I'm gonna start with a SOHC cam... it's one cam, carries lobes for both intake and exhaust valves. the profile of the lobe is like an egg shape if you will... and egg has a round bottom part (this is where the valve is closed) and like a pointy top part (where the valve is open)... the shape of this pointy top part determines duration and lift... overlap is determined by duration and the relationship of one lobe to the other (exhaust and intake lobes). so anyways, where was I.... oh yeah SOHC cam, ok it's got 4 lobes for each cylinder, for a total of 16 valves. two intake, and two exhaust valves. when cyl 1 is at top dead center, the valves are closed, and cylinder 3 is also at the top of it's travel, except cyl one is in the compression stroke, and cylinder 3 I think is at the end of it's exhaust stroke, the next time cyl 3 comes down it'll be sucking in an intake charge... the firing order is 1-3-4-2. ok, so everyone got this... 1 and 3 are up together, 2 and 4 are down together. so the camshaft is spinning in a 1:2 ratio to the crank, like you turn the crank 180 degrees, the camshaft turns 90 degrees... everyone with me so far? so... on the cam, the lobes for cyl 1 and 3 are offset by 90 degrees, that's why when you do a lash adjustment you follow the firing order. yes? yes.
ok, so these camshafts dictate the timing, lift, and duration of the lift event for the valves... the basically open and close the valves. the opening and closing of the valves affects many many many things in the engine, from emissions, vacuum, idle quality, scavenging effect, and finally and most importantly to us... volumetric efficiency. the engine is sucking in fuel/air and pushing out exhaust gasses past these valves... the easier we make it for the engine to do this, the better power we get (simple explanation, I could make it more complicated but there is no need). that's why a cam is so important and why there is so much discussion about them. that's also why a cam is useless w/o tuning... if you can't compensate for the increase in volumetric efficiency, you've done nothing. also, this is why you gotta also make sure you've removed all other restrictions that can cause pumping losses like better filter/intake, header and exhaust.
now, the valves and pistons are real close neighbours, you give the valve too much lift and it'll hit the piston, so when building an engine, that's why you gotta clay the pistons with the head installed and the correct cam you plan to use. also, at really high speed, you gotta remember these valves weigh... and weight and speed equal momentum (thanks Sir Isaac Newton), basically what goes up must come down... that's what the spring is there for... too heavy a valve, too much rpm, too long a duration etc.... valve float occurs, and the piston goes smash to the valve. not good. so, big cam and high rpm, you want lightweight components... light valves (maybe even machined stems), light retainers, stiffer springs, etc...
now DOHC, the intake and exhaust cams are separate, so you can affect cam timing and overlap by using adjustable cam gears... that's why DOHC engines make a lil extra power, the events are better timed, even though there are parasitic losses (very slight BTW) from having ONE more rotational assembly.
now, add VTEC to this, VTEC is just a way to affect geometry of how the camshaft acts on the valves, thereby changing the timing on it. VTEC is a whole other beast, you can do a search or read up on temple of vtec or something... it's well documented for even a basic level of understanding, all the way to a very advanced level.
anyways, I just covered this real quick and fast off the top of my head, if there are any corrections, additions, etc.... feel free to toss it out there plz. I just thought I'd bring the n00bs up to par so they can read with intelligence.
also, I don't wanna hear all this isht about Skunk 2 this or Blox that or CompCams such and such. cut that noise! I wanna hear the specs on the bitsh, lift, duration, overlap... what are the actual specs, why did you choose those specs, what do you believe they will in theory do for your volumetic efficiency. I personally dunno much more about this... the book someone (
you know who you are, lover ) lent me had all this info but I failed to read it in a timely fashion so I remain in the dark as of now.
04-Apr-2007, 09:59 PM
#19
Originally posted by bbarbulo
when cyl 1 is at top dead center, the valves are closed, and cylinder 3 is also at the top of it's travel, except cyl one is in the compression stroke, and cylinder 3 I think is at the end of it's exhaust stroke, the next time cyl 3 comes down it'll be sucking in an intake charge... the firing order is 1-3-4-2. ok, so everyone got this... 1 and 3 are up together, 2 and 4 are down together.
when cyl 1 is at top dead center, the valves are closed, and cylinder 3 is also at the top of it's travel, except cyl one is in the compression stroke, and cylinder 3 I think is at the end of it's exhaust stroke, the next time cyl 3 comes down it'll be sucking in an intake charge... the firing order is 1-3-4-2. ok, so everyone got this... 1 and 3 are up together, 2 and 4 are down together.
You're right about the firing order 1-3-4-2, so while 1 is at the top/beginning of the intake stroke 4 will be at the top/end of the compression stroke/beginning of the combustion stroke and 2 will be at the bottom/begging of the compression stroke while 3 is at the end of the combustion stroke/beginning of the exhaust stroke.
