Camshaft Weights!
Originally Posted by Gruppe-S
Actually from a physics standpoint becuase the mass is rotating you will actually see a greater effect from the reduction of mass. This is similar to the positive benefits of reducing wheel weight and their effect on performance. Simply shaving 2lbs off a rotating wheel is worth far more than shaving 20lbs off the weight of the vehicle. Although it is true that the inertial mass is close to the center of spin, you always have to keep in mind you have camshafts (and gears!) spinning at 7000+RPM.
Here's Mitsubishi's own comments regarding the hollow camshafts - "Under the magnesium valve covers, hollow camshafts save rotational weight, and less inertia means that engine RPMs build faster and acceleration times go down. " - Mitsubishi Motors USA
Although it is difficult to measure the true benefits of the weight of camshafts, I think it's reasonable to say Mitsubishi invested some time and energy in making hollow camshafts - it is very difficult for any camshaft manufacture to make a chilled-cast hollow camshaft that can withstand the high revs found in modern high performanc engines. This is primarily why none of the chilled-cast camshafts have hollow cores, and why Helix was only able to do it with a billet core. And for Mitsubishi to invest this time and energy, there must be substantial performance gains, as God knows they didn't invest much time and energy on the interior of our cars!
Cheers,
Gary
Gruppe-S
Here's Mitsubishi's own comments regarding the hollow camshafts - "Under the magnesium valve covers, hollow camshafts save rotational weight, and less inertia means that engine RPMs build faster and acceleration times go down. " - Mitsubishi Motors USA
Although it is difficult to measure the true benefits of the weight of camshafts, I think it's reasonable to say Mitsubishi invested some time and energy in making hollow camshafts - it is very difficult for any camshaft manufacture to make a chilled-cast hollow camshaft that can withstand the high revs found in modern high performanc engines. This is primarily why none of the chilled-cast camshafts have hollow cores, and why Helix was only able to do it with a billet core. And for Mitsubishi to invest this time and energy, there must be substantial performance gains, as God knows they didn't invest much time and energy on the interior of our cars!
Cheers,
Gary
Gruppe-S
what is nice is that you'd shave 4 or rather not ADD 4 pounds to a high part of the vehicle. that's like having another carbon fiber hood, or not... having... another... carbon fiber hood....
Interestingly, everyone seems to be assuming all the weight difference is at the center of the camshaft. However, because the Helix save their weight across the whole of the cam, would not the lobes be lighter than those of the HKS? This in turn would make the, albeit small, weight savings even more beneficial.
uhm... if the helix cam is hollow then the lobes are very minimally lighter than cam shafts which are not hollow, you're talkin' fractions of an ounce if in fact billets are lighter than casts.
Obviously the weight differential is small. But since we are all talking theoritical here without any actual observed data, other than weight, a weight differential at all is a benefit.
3500+rpm is still a fairly high rotational speed. Without some emperical data that shows having this small weight differential doesn't benefit response or wear, it's all speculation. What we do know is that less energy is loss when accelerating things that are lighter.
3500+rpm is still a fairly high rotational speed. Without some emperical data that shows having this small weight differential doesn't benefit response or wear, it's all speculation. What we do know is that less energy is loss when accelerating things that are lighter.
Last edited by articfury; Sep 19, 2006 at 03:33 AM.
this is interesting info but selecting, or even considering selecting, a camshaft by weight makes as much sense as buying a certain brand of brake pads because you like the color of the box. Power is generated by the cam's profile and an "optimum" grind heavier cam will make more power than a lesser grind lighter cam. You can debate rotating mass all you want but the profile is what matters, is what will build power, and is all that should be considered when selecting a camshaft.
Originally Posted by Steve_P
this is interesting info but selecting, or even considering selecting, a camshaft by weight makes as much sense as buying a certain brand of brake pads because you like the color of the box. Power is generated by the cam's profile and an "optimum" grind heavier cam will make more power than a lesser grind lighter cam. You can debate rotating mass all you want but the profile is what matters, is what will build power, and is all that should be considered when selecting a camshaft.
Last edited by mchuang; Sep 19, 2006 at 08:54 PM.
Good for Helix. I never understood why many of the aftermarket race cams weren't hollow. The lower weight won't translate into power, but it could only help engine responsiveness. Are there any WRC teams that don't use hollow camshafts? 
What I really find amusing, other than the good technical discussion, is that Mitsu stated the reason they made the camshafts hollow. I forget where, but it was in the literature I believe. It was the same reason they went with the magnesium valve cover. They did it all in an effort to lower the engine's center of mass. I don't recall them making a statement about the cams in an attempt to lighten the reciprocating assembly for that purpose.
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Originally Posted by Zeus
What I really find amusing, other than the good technical discussion, is that Mitsu stated the reason they made the camshafts hollow. I forget where, but it was in the literature I believe. It was the same reason they went with the magnesium valve cover. They did it all in an effort to lower the engine's center of mass. I don't recall them making a statement about the cams in an attempt to lighten the reciprocating assembly for that purpose.
Either way if you can feel a difference that you can directly attribute to the weight of the cams and not the grind you are either a god or a liar.
Hey, my recollection is not quite what it used to be... I would not be greatly surprised if I were wrong. I'd almost swear though that I remember reading it being an over all weight savings issue.
Amazing that so many believe because the cams are rotating that lighter cams would have a performance difference. making the cams 4 pounds lighter is for all practical purposes the same as just lightening the car 4 pounds. But hey 4 pound is 4 pounds. Do it 10 times and you have 40 pounds savings. If you really want to keep the valvetrain trick, stop overspringing your cams. Stock springs are only 52lb seat pressure. Very easy to turn cams on the bench. After market springs are 70-95lbs seat pressure. Very difficult to turn cams on the bench with 70lb springs. Amazing difference. About 100 times more important than making the cams lighter.
Originally Posted by hotrod2448
I remember seeing a poster on the wall at the dealership when I was buying my first Evo saying it was in an effort to increase engine response. I don't ever remember reading anything about them doing it to help the center of gravity. I'm not saying it wasn't that as well but, I specifically remember them saying it was to increase responsiveness.
Either way if you can feel a difference that you can directly attribute to the weight of the cams and not the grind you are either a god or a liar.
Either way if you can feel a difference that you can directly attribute to the weight of the cams and not the grind you are either a god or a liar.
Thats not a very acurate test because you left the bag on the HKS....how do we know that bag isnt a steel indistruct-o see through cover that weighs 2 lbs......wtf why can people just do acurate tests so we dont all get wrong information.
lol
lol
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Hi
Good debate going on here. Here's Mitsubishi's comments regarding the camshafts:
hollow cored camshafts "save rotational weight, and less inertia means that engine RPMs build faster and acceleration times go down" - Mitsubishi website RE Lancer Evolution
The Helix cams are actually lighter all around, as a billet camshaft is inherently lighter due to the material properties than a chilled cast camshaft. The camshaft is also harder so will have longer longevitiy than a chilled cast unit. As for the RPMs, my bad
I used to have the HKS cam gears and HKS 272's in my car and switched to the Helix 272's with the cam gears. The weight savings is substantial, considering the HKS cam gears weigh in at 1lbs 3 oz (and much larger in diameter than a cam!) as opposed to 0.99lbs of the Helix cam gears. Most of the weight savings is around the outter hub/gear also. The car honestly does respond faster, especially in terms of boost response on shift, and does feel to rev happier although I have nothing to gauge that with. The idle is also less rough (I'm on stock valve springs). As far as horsepower, on the stock 16G (10.5 hotside) the horsepower was identical to the HKS cams, actually it was four wheel horsepower more, but I mean 4 whp is like a couple degrees in temperature (dynoed on different days)
Cheers,
Gary
Gruppe-S
Good debate going on here. Here's Mitsubishi's comments regarding the camshafts:
hollow cored camshafts "save rotational weight, and less inertia means that engine RPMs build faster and acceleration times go down" - Mitsubishi website RE Lancer Evolution
The Helix cams are actually lighter all around, as a billet camshaft is inherently lighter due to the material properties than a chilled cast camshaft. The camshaft is also harder so will have longer longevitiy than a chilled cast unit. As for the RPMs, my bad
I used to have the HKS cam gears and HKS 272's in my car and switched to the Helix 272's with the cam gears. The weight savings is substantial, considering the HKS cam gears weigh in at 1lbs 3 oz (and much larger in diameter than a cam!) as opposed to 0.99lbs of the Helix cam gears. Most of the weight savings is around the outter hub/gear also. The car honestly does respond faster, especially in terms of boost response on shift, and does feel to rev happier although I have nothing to gauge that with. The idle is also less rough (I'm on stock valve springs). As far as horsepower, on the stock 16G (10.5 hotside) the horsepower was identical to the HKS cams, actually it was four wheel horsepower more, but I mean 4 whp is like a couple degrees in temperature (dynoed on different days)
Cheers,
Gary
Gruppe-S
Last edited by Gruppe-S; Sep 20, 2006 at 06:23 PM.