Helix 2 vs MaxSpool? Opinions

TMONEYDIESEL said:
Hey Don, We just installed a Helix 2 in my 12 valve, im running twins with a HTT stainless 65/13 to a big brother, around a 1000cc's p-pump, what should i expect from the Helix2?
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A broken cam?:hehe: I use the same cam in my 12V with a 13mm pump. Runs hard past 4500 and will push you back in the seat much better past 3000 VS a stocker.
 
Soup Nazi said:
The other parts of your post was mostly incorrect, so I did not even bother to quote it. Im back to that brick wall theory I hold so dear.

Anyway, with duration numbers that low people may as well keep the stock cam in the truck. Stock durations are as follows:

12V: 155 intake and 200 exhaust
12V Marine: 175 intake and 202 exhaust
24V : 161 intake and 202 exhaust
CR: 161 intake and 192 exhaust

The Maxspool numbers look like you took a stock marine 12V intake lobe and snatched an exhaust lobe from someone I know very well and called it a "designed" cam. Those duration numbers match perfectly. :badidea:

Cams are probably the most copied part in the hot rod business. Some grinders have a zero degree of sophistication
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Soup Nazi said:
Pat,



Diesels are NOT that way at all. Diesel cams are very short on duration when compared. When we want more fuel, we just inject more through the fuel delivery system. Diesels also have a very wide range at which the air/fuel will burn and continue to make power. Gassers dont. They have a very thin range of making efficient power with parts per air and fuel.

Diesel cams come very optimized right from the factory and the further you play outside a window of what works, the worse things get. This is part of the reason we see so many flops in cam grinds that are supposed to enhance performance. Adding duration to a Diesel cam can get one into trouble fast. We only need to look at some of the fastest 12V trucks running around the drag strip to see that stock cams are super. Of course the fastest VP44 and CR engines are using an aftermarket cam. The H2.

Regardless, we cant look at a radical number on a Diesel cam and say " that one is better" or "it makes more power" on a Diesel like with gassers. Honestly I think it would cause more confusion and less performance in the end if the numbers were published.

Tricks of efficiency are what the H cams use. More airflow, hence lower EGT. HP is rarely found with a Diesel cam change and if so it is on the order of 20 or less at peak. Power band changes or when the power comes on is the best anyone can do.

Going radical is fruitless. Big numbers are bad.

I have dyno tested some radical stuff we tried and cam profiles from the more dirt oriented puller stables. It was all junk and cost, in some cases over 100 HP.

You cant gain big with a Diesel cam, but you can certainly lose. Thats not counting the countless bent push tubes and valve float from using unmatched springs and lobe designs.
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Most people only look at the numbers at .050 and don’t understand acceleration rates of the lifter. Numbers at .050 don’t mean much one way of the other if you don’t beef up the .200 number. I could post the .006 .020, 050 and .200 numbers of others cams, if they them self’s only knew them.
 
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Soup Nazi said:
That is exactly the problem with the regrinds. Once you grind off base circle material you end up adjusting too much on the rocker arm to get the lash set back.

What COMP is not telling you is that the centerline of the lobes has to change as well. This means you grind more than just the base circle off. Depending on how far you change the centerline of the lobe determines how much gets whacked off the ramp area. I found early that a stock CUMMINS cam will not last long after you play with intake and exhaust centerline points to get the lobe seperation you need to run a longer durations.
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And thus we come back to my previous post..

I'm a bit sick of the bashing, by raping an pillaging others posts, that seems to follow you around..
I'm not an engine builder, lets get that out there.. But here's my issue..
I see the diagrams Greg posted and they make sense to me.. Making the base circle smaller = more lift.. And = faster ramp..
Where does the centerline affect the price of rice in china?
Yes a smaller base = faster ramp.. Is this an issue? For most I would suspect not.. My question, when I asked you and Racin in my thread, what is the difference between running my old 215K cam vs a regrind from Greg.. Ya know who answered?
So to sum it up, it sounds like a perpetual pissing contest, with the breeze in your direction..
I'm not trying to be an ass, but it pisses me off when people say their stuff is better, just because they say so.. You guys running 4700rpm pullin sleds may have issues with regrinds, but what the hell is the difference when these motors have 500k with the stock cam??? A regrind should do the job for "most" of us without the expense....

So, give some details (proof) to discredit the use of regrinds, CompyCams, etc... For right now you sound like an arrogant ***** touting your stuff vs his stuff everytime this comes up..

We all want valid info to base our $$$$ on, if you can't give that, then why are you here?

Brad
 
COMP461 said:
Most people only look at the numbers at .050 and don’t understand acceleration rates of the lifter. Numbers at .050 don’t mean much one way of the other if you don’t beef up the .200 number. I could post the .006 .020, 050 and .200 numbers of others cams, if they them self’s only knew them.
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Oh COMPY I know the numbers of my cams lobes and stock Cummins lobes in 1 degree increments throughout the entire 720 degrees.
 
A 1000 cc pump with such small chargers is going to be interesting!!!
TMONEYDIESEL said:
Hey Don, We just installed a Helix 2 in my 12 valve, im running twins with a HTT stainless 65/13 to a big brother, around a 1000cc's p-pump, what should i expect from the Helix2?
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Soup Nazi said:
A broken cam?:hehe: I use the same cam in my 12V with a 13mm pump. Runs hard past 4500 and will push you back in the seat much better past 3000 VS a stocker.
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:hehe: oh great a broken cam well thats reassuring thx Don and 13mm is the size im running also, hopefully it doesnt break and just puts a big smile on my face as i get pushed harder into the seat passing 5000
 
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Distributor said:
A 1000 cc pump with such small chargers is going to be interesting!!!
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i thought the s400 would be a good bottom turbo and the sled puller 66/13 stainless would help out on some quicker spool on my 5spd,
 
Ridemywideglide said:
For right now you sound like an arrogant ***** touting your stuff vs his stuff everytime this comes up..
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You just summed up every post Don M has ever made.
 
TMONEYDIESEL said:
i thought the s400 would be a good bottom turbo and the sled puller 66/13 stainless would help out on some quicker spool on my 5spd,
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You do know that guys that pull have less than the 1000 cc's you want and have a small charger bigger than your big one???
 
I think that CL numbers should fall where they will, you should look at cam timing as four events open and close of the exhaust and open and close of the intake. If you like the place where the intake opens then adding duration to the end of the intake event will increase the CL by half the amount you add. the same goes true for the exhaust , I like to open the exhaust event earlier on a big single and use blow down pulse the charger to aid in lighting a larger charger. I can do most anything with in reason on a stock 24 valve core with out losing more then .100 base circle on street type trucks.

The stock Cummins core is cast steel and has induction heat treat deep in the core. We have goon as far as .250 off the base circle and the hardness as measured on the Rockwell C scale is still harder then a cast iron or chill iron aftermarket core. It’s amazing how well Cummins engineers their parts. This is apparent in many other parts that hold up to power levels that in a performance gas application with require total reengineering

One thing about a Cummins valve train, even at 6000 RPMs which is twice the designed level the parts stay together relative well. I had a runaway 4 years ago on the ProJacks and we were data logging a converter test. The engine went to between 5800 and 6280 RPMs most of it free rev, which is devastation on a valve train, this was a recorded 90 + second event, the data logger timed out after that. We didn’t suffer any breakage and the valve springs lost nothing in seat pressure.

Take a stock small block Chevy and turn it double and the carnage would be enormous

In reality the load on valve train goes up geometrically with rpm, that is why we can do some of the great things with a Cummins that are not possible with a gas type lobe profile which must rely on and were originally designed for a .800 or .900 lifter diameter.

One other aspect of the diesel, the science of air flow dose not stops when you start using # 2 as a fuel. A diesel is a four stroke, Otto cycle internal combustion, reciprocating power plant. Nothing more, nothing less. Air flow is the only limiting factor in porpuse built high performance engines, fuel is relative easy.
All engines rely on atmospheric pressure to push air in to the combustion chamber. A turbocharged diesel is no different. Before you all start to disagree, remember that on a turbo charged engine you have boost or positive pressure on the intake track, and you have a almost equal pressure on the exhaust track call turbine inlet pressure or drive pressure. So the difference is on a normal aspirated engine you have an absolute pressure of 14 psi on both sides of the engine and you must rely on the piston opening up a void to cause a depression in pressure to fill the chamber. And a turbocharged engine has close to equal boost and drive. This is the advantage of trying to reduce drive pressure
 
I wish i was smarter and understood this a little better then what I do. Thank you for sharing the info with us. Comp what cam would you recomend on a 24v running a set of 35/S400 twins and a large set of sticks?

Andy
 
Which cam will last longer, which will have less strain on parts for a CR?
 
Rods said:
no advantages in wider say 112 to 114 ?
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I've been down that road before, don't go there, absolutly no velocity on the bottom end, after say 2400 it's all good and pulls hard on the top!

Jim
 
I guess the gasser thinking is way off ? You know jim how a little ford likes a 112 to 114 LCA when coupled with a power adder to help get them going , least mine was with a F cam and a T70
 
Question for Don M:

We only need to look at some of the fastest 12V trucks running around the drag strip to see that stock cams are super. Of course the fastest VP44 and CR engines are using an aftermarket cam. The H2.
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Don is there not really the need for a cam in the 12V? Wonder if you can elaborate on the above quote? Thnx, Jim
 
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