Cams in street applications!

Erik@LCD said:
FYI, you can run a little tighter (.08-.09 intake and .18ish for exhaust) for even greater effect
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Recommended is .10 and .20 right? Where are you seeing a difference in having the valves set a little tighter? power? less smoke, lower egt's or spool up?
 
You'll see slightly less smoke, better spool, smoother idle and better response... but about 75* higher egt. I set mine at .008/.017
 
I have a Hamilton Big Stick in mine, better spool up, lower egt's, less smoke, SMOOTH IDLE, pulls hard on top end!! All in all.... id do it again for sure!!
 
soulezoo said:
You'll see slightly less smoke, better spool, smoother idle and better response... but about 75* higher egt. I set mine at .008/.017
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Thanks for the info. the altitude where I am at is 4800 ft so I have a bit of disadvantage when it comes to spool up and smoke with the thinner air up here. My truck drives like an absolute animal around sea level, I could not have been happier. Then I get it home and had the wind taken out of my sail. not nearly as fun to drive. I have to be a bit more easy on the peddle until it starts to light up...
 
coon smile said:
If I was not running an aftermarket cam (Fletcher's drop in), I never would have asked Engineered Diesel to build me a 66mm charger to run over their s476 on my daily driver.
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That's great to hear...Did you use the "killer bee" or the "108" cam? They are both drop in's...What elevation are you at? I have twins, 64mm and a S480 with flux 5.1's, I wouldn't mind going to a 66mm and an S483 or S495 if it spools like I am thinking it will. What size injectors are you using?
 
MMAguy said:
Thanks for the info. the altitude where I am at is 4800 ft so I have a bit of disadvantage when it comes to spool up and smoke with the thinner air up here. My truck drives like an absolute animal around sea level, I could not have been happier. Then I get it home and had the wind taken out of my sail. not nearly as fun to drive. I have to be a bit more easy on the peddle until it starts to light up...
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I am at 4000 ft myself... I understand...
 
MMAguy said:
That's great to hear...Did you use the "killer bee" or the "108" cam? They are both drop in's...What elevation are you at? I have twins, 64mm and a S480 with flux 5.1's, I wouldn't mind going to a 66mm and an S483 or S495 if it spools like I am thinking it will. What size injectors are you using?
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I don't know which one it is. I think it's the older one, because I got it in the spring of 2009.

Injectors are a modest 6x12.
 
cams

I have had good sucess with my maxspool cam from "comp461" i was able to increase the size of my exhaust housing with no change of orginal spool without the cam. I was happy with the spool before but i wanted top end and it gave me exactly that.
I ended up with 150rpm decrease in spoolup time and almost 200 degree drop in peak temps and 100 degree drop in cruise temps. It might sound like small increases but in our diesels it means alot. I feel i could step up another size of exhaust housings to a 16cm on the s300 and turn the fuel up a hair and have the same temps as before the cam, at cruise and peak, but have even quicker spoolup frfom the increase fuel and make more power than ever.
Greg is a easy guy to deal with just have all you info ready fueling turbo gearing.
I would encourage everyone that is not doing other things at the same time or could wait to do the other things, to dyno their trucks before and after you will see the difference and be happy you spent the money.
 
MMAguy said:
That's great to hear...Did you use the "killer bee" or the "108" cam? They are both drop in's...What elevation are you at? I have twins, 64mm and a S480 with flux 5.1's, I wouldn't mind going to a 66mm and an S483 or S495 if it spools like I am thinking it will. What size injectors are you using?
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Im running a Big Stick 107 from Hamilton Cams, and I frequent the Tahoe area for snowmobiling. I am running 90hp stix, 64mm charger and Stg3 pump...my truck at 7500+ft spools excellent when towing and with the PoD I can drive "Smoke Free" climbing a 10% grade up to the staging area thats 10+ miles long.

For me the cam has been the single best engine mod to date.!!!!
 
If these aftermarket camshaft profiles are so much better for spoolup it makes me wonder why on earth didn't the engineers that designed the engine do it to begin with?

I mean, usually you change a camshaft to optimize an engine operating range outside of what the engine was originally designed for. Usually higher rpm values are what we seek because if we make the torque higher, we can make more power, run faster, pull harder, yada yada yada.

But if you guys are noting better response off the bottom (spooling the charger(s)) then this isn't the case. It's actually doing better than the stock piece in the range the engine was designed for.

So are the Cummins engineers that designed the OEM camshaft profile just dumb? Or what?


And lastly, what type of change is made that helps spool? What is the conception behind the profile changes being made?
 
Charles said:
If these aftermarket camshaft profiles are so much better for spoolup it makes me wonder why on earth didn't the engineers that designed the engine do it to begin with?

I mean, usually you change a camshaft to optimize an engine operating range outside of what the engine was originally designed for. Usually higher rpm values are what we seek because if we make the torque higher, we can make more power, run faster, pull harder, yada yada yada.

But if you guys are noting better response off the bottom (spooling the charger(s)) then this isn't the case. It's actually doing better than the stock piece in the range the engine was designed for.

So are the Cummins engineers that designed the OEM camshaft profile just dumb? Or what?


And lastly, what type of change is made that helps spool? What is the conception behind the profile changes being made?
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I'm quite sure these cams open the exhaust valve alot sooner or sooner at the very least. I'd think this would lead to more emissions given there's less time for the cylinders content to remain in the cylinder which may not promote as clean/complete of a burn. Clean being a term the EPA has come up with.
 
NickTF said:
I'm quite sure these cams open the exhaust valve alot sooner or sooner at the very least. I'd think this would lead to more emissions given there's less time for the cylinders content to remain in the cylinder which may not promote as clean/complete of a burn. Clean being a term the EPA has come up with.
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But some of these guys are talking about 12v trucks too. Maybe not in this thread, but the sentiment is the same.

I'm not aware of any real emissions issues with those old mech engines, yet the guys that swap cams seem to have the same reports.

If it is emissions driven, even on those engines then that explains it. Otherwise, how did the Cummins guys screw up so bad?

Is it emissions then?
 
Charles said:
But some of these guys are talking about 12v trucks too. Maybe not in this thread, but the sentiment is the same.

I'm not aware of any real emissions issues with those old mech engines, yet the guys that swap cams seem to have the same reports.

If it is emissions driven, even on those engines then that explains it. Otherwise, how did the Cummins guys screw up so bad?

Is it emissions then?
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Charles my 12v truck came with a catalytic converter so I would assume there was thought given to emissions. But honestly not alot ot thought just as today not alot of thought is given to emissions if you want my honest opinion. I've said this before, shoving potatoes in the exhaust pipe and putting toilets under the hood are not good ways to solve emissions problems. Addressing the emissions from the source, the breathing and fuel distribution in the motor itself, are the keys to reduce emissions and achieve whatever mpg the manufacturer wants. Guess why you don't see that, because no one else is doing it either. Sorry for the slightly off tangent rant.

In the case of the 12v it came down to this I think. They needed between 160 and 215 hp out of a 360" turbo charged 17 to 1 motor. Only a very small turbo charger was needed for that so tons of thought was not going to be put in to the cam program nor the cyl head. I don't think you'd see a huge difference in spooling a stock hx35 with stock exhaust, stock fueling, and a stock intake with a cam if any at all.
 
I would think spooling a large charger was the last thing on Cummins minds when they engineered their cam profiles....And with longevity being one of Cummins top concerns I would think they wanted the least aggressive ramp rates possible.
 
Reading Charles' question 2 things came to mind... Same things Nick and Sinner said...

How easily our tiny turbos spool with a stock cam, and the accelerated wear and increased stresses from higher ramp rates...

Neither is a benefit for Farmer Brown trying to move some hay and feed, or the hotshot driver, or camper puller...

The limitations of a stock cam become visible when numerous non stock parts are used, by people paying a great deal of attention to how the truck runs, as they try to get every bit of performance out of it. Which the average owner won't be doing.

And there is little incentive for Cummins to spend major R&D on something that doesn't need to be the ideal high perf part. Different usage...
 
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