Heads/Cams?

[Jivepepper]

I hope to purchase MMR stage 3 heads in the next week or two, and was considering upgrading my cams too.

So far the two I have considered, are Cushman stage 3 blower cams, or a stage 3 custom grinds from comp and MMR.

I have been running Houston Performance S292 cams on the stock heads and have been very happy with them. I picked up about 80 hp with them and just a retune.

The specs for the HP s292 are:
.531/.531 lift, 242/242 .050 duration, 114 LSA.

The Cushman stage 3 blower cams are:
.545/.545 lift, 238/242 .050 duration, 115 LSA.


Besides .014 of lift and 1 degree of lobe separation both cams are very similar, and I was wondering if they would really help much. I actually paid more the for the HP's compared to the price of the Cushman's

The Cushman grinds are the same as the VT stage 3 cams for those who might not know that Jim started his own company after VT engines.

So my options are (Unless some thinks of something better) are:

Keep the HP s292 cams

MMR/Comp custom grind. But MMR is better known for turbo set ups

Cushman stage 3 blower cams. (Formerly VT engines)

I appreciate the suggestions and info. Thanks!

[SonofaBish]

Like you said, the new cams you're looking at have more lift, but you have more intake duration on the old cams..... Personally, i wouldnt change them....
I just doubt you'd see a big change in power either direction...

[Rodeheaver's]

i like the 115 lobe separtion on the other cams, those blower cars love the bigger lope sep...

[gmkillr]

LSA is the result for the required valve events not a guide that needs to be followed.
The cam events are what makes the cam. Simple lift and duration are pointless.
What makes a cam "good"?
The cam events.
The rate in which the lobe accelerates.
The lift.
The dwell at lift.
These are what makes the intake center & exhaust center.
The centers make the LSA.
Not backwards.

[Rodeheaver's]

i was under the impression that lsa meant "lobe separation angle" and its a proven FACT that forced induction engines like a larger LSA...and Na engines like a closer LSA.. Stick to what you dont know boy...

[gmkillr]

Read my last post a little closer, because it is FACT.
People who choose a cam based off of the LSA have NO idea what they are doing when it comes to choosing a cam. Am I saying that I know it all? Not by any means, but atleast i'm willing to admit it and learn.......
Maybe you should take your own advise and stick to what you know boy... Mr. Jack of all trades, Master of none......

[Jcelli04]

another place you might wanna check out is Modular Power House. they will custom grind you a cam to fit your needs perfectly. or im pretty sure they have cams already made for centri blower cars.

i know they have kenne bell cams

[gmkillr]

If you want to speak to an EXPERT on cams then go here.
www.CamshaftInnovations.com
Great guy to deal with and has unlimited knowledge when it comes to valvetrain technology.

[Rodeheaver's]

mod motors and pushrod motors are slightly diff when it come to cams, the mod motors dont react to lift as much as pushrod motors, they really respond to duration and LSA... LSA can make or break a mod motor, its hard to make NA power in a mod motor so more people use forced induction on em and it has been proven that forced indution motors love a big LSA, or course cam events are important but on a mod motor as far as i know there have only been slight changes from stock in cam events, the duration and lifts are played with very little, heck comp never used to make a cam over 550 lift, just duration and LSA changes.. jsut my 0.02$, didnt mean to get mad before.. Its cool man, i know you only give praise to people that screw you and that wasnt me..... cough cough Jay Allen...

[u1arunit]

Stick to what you dont know boy...

Maybe you should take your own advise and stick to what you know boy... Mr. Jack of all trades, Master of none......

Hey guys don't make it personal.

[95riosnake]

man, this is becoming another thread to get the out for between you two

[SonofaBish]

I took rodeheaver's post to mean that boost like cams with higher LSA .... not necessarily that you should choose your cam BASED on LSA alone...

One thing the OP may want to consider is valve overlap... I don't know much at all about mod motors, let alone their cams, but valve overlap is [(intake+exhaust)/4-LSA]*2 (unless its different b/w mod motors)

When i researched cams for my setup, for boost, you wanted to stick with 6* of overlap or less.... you don't want air that you're pushing in (boost) to just go right back out the exhaust valve.... Now, obviously, that's going to be very tough (or impossible) when you get into setups with larger duration cams like the OP is speaking of... But then again, mod motors may be completely different than my motor...
just something to take into consideration

[Jivepepper]

I might just put the ported heads underneath the cams I have now, and see what it does. I was just trying to avoid doing things again, but if I good save some money on new cams it would really help. I'm on the borderline of being able to afford and justify it.

[no1sirbutler]

Damn Jive your a modding fool anymore. LOL

[Jivepepper]

Damn Jive your a modding fool anymore. LOL

And I'm still slow.

[gmkillr]

*Lobe Separation Angle* (LSA)
You have the intake opening @ .050" and the intake close @ .050". Together these items make duration @ .050" and the intake center (IC).

You have the exhaust opening @ .050" and the exhaust close @ .050". Together these items make duration @ .050" and the exhaust center (EC).

Anyone who knows anything about camshafts goes about it from this avenue. They may look at different aspects of the engine in the designing phase by looking at velocity, pressures, cylinder pressure, etc, but in the simplest of terms, this is how it starts.

Basic remedial math here.

The (IC) + the (EC)/(2) = LSA

[B]Thus, the average of the centers is the LSA. When you speak to a guy who claims that camshafts aren't voodoo and speaks in terms of LSA, well, he's very uneducated. When a person says LSA, what is he really saying?[/B]

Example.

I design a camshaft and I feel as though the events at .050" need to be:
IO = 15
IC = 55
EO = 66
EC = 14

Now put these together. The in @ .050" = 250* and the ex @ .050" = 260*. These events make the IC = 110 and the EC = 116. Thus.......

110 + 116 = 226.......226/2 = 113 LSA

In the above example, those EXACT opening & closing events yield the specs above. Period. Now when a guy comes along and says that a 113 LSA is a NOS cam, a motor cam should have tighter LSA (or more common going from motor to NOS) that ALL you need to do is change the LSA, you cannot just magically change the LSA. Its impossible.

Backwards. 110 + 116 = 226/2 = 113 EVERYTIME. But if I come at it and say I want a 113 LSA, how many different combinations of numbers can you have and get to 113?
Infinate.
The point is, LSA alone shouldn't be a parameter to compare/select cams since it is derived from the important details.....valve timing events. You could have several cams with the same LSA, but with totally different characteristics. LSA is built-in the cam grind as a result, not a target, and not adjustable.

[Rodeheaver's]

*Lobe Separation Angle* (LSA)
You have the intake opening @ .050" and the intake close @ .050". Together these items make duration @ .050" and the intake center (IC).

You have the exhaust opening @ .050" and the exhaust close @ .050". Together these items make duration @ .050" and the exhaust center (EC).

Anyone who knows anything about camshafts goes about it from this avenue. They may look at different aspects of the engine in the designing phase by looking at velocity, pressures, cylinder pressure, etc, but in the simplest of terms, this is how it starts.

Basic remedial math here.

The (IC) + the (EC)/(2) = LSA

[b]Thus, the average of the centers is the LSA. When you speak to a guy who claims that camshafts aren't voodoo and speaks in terms of LSA, well, he's very uneducated. When a person says LSA, what is he really saying?[/B]

Example.

I design a camshaft and I feel as though the events at .050" need to be:
IO = 15
IC = 55
EO = 66
EC = 14

Now put these together. The in @ .050" = 250* and the ex @ .050" = 260*. These events make the IC = 110 and the EC = 116. Thus.......

110 + 116 = 226.......226/2 = 113 LSA

In the above example, those EXACT opening & closing events yield the specs above. Period. Now when a guy comes along and says that a 113 LSA is a NOS cam, a motor cam should have tighter LSA (or more common going from motor to NOS) that ALL you need to do is change the LSA, you cannot just magically change the LSA. Its impossible.

Backwards. 110 + 116 = 226/2 = 113 EVERYTIME. But if I come at it and say I want a 113 LSA, how many different combinations of numbers can you have and get to 113?
Infinate.
The point is, LSA alone shouldn't be a parameter to compare/select cams since it is derived from the important details.....valve timing events. You could have several cams with the same LSA, but with totally different characteristics. LSA is built-in the cam grind as a result, not a target, and not adjustable.

hey whatever sight you right click and saved that from should be torn down, it is pretty WRONG.. And i dont feel i need to explain myself any further, Just try and be a little disernful in the future, you can't believe everything you read on the web...

[gmkillr]

Copy the above post and send it to the president or owner of Comp Cams and see what he'll say about it. I can gaurentee that he'll say the information is 100% correct. I'm not trying to take credit for ALL of the above information but some of it's mine and the rest is credited to a highly respected sbftech member. I don't claim to know it all, far from it infact, but I do know when I can learn from others, I'm willing.

[mineralrob]

And I'm still slow.

I would take 11.2's anyday. Sounds fast enough for me:D

[SonofaBish]

Copy the above post and send it to the president or owner of Comp Cams and see what he'll say about it. I can gaurentee that he'll say the information is 100% correct. I'm not trying to take credit for ALL of the above information but some of it's mine and the rest is credited to a highly respected sbftech member. I don't claim to know it all, far from it infact, but I do know when I can learn from others, I'm willing.

So, when do you plan to go to Rodeheaver's to have new cams put in??

....


easy now boys.... like Mark said above, don't make it personal...