Stroker specific cams?

[DrEamer]

IMHO.... A lot of what is being missed here is that you are going to use EFI. One key on the cam used for that 351W EFI build is that the LSA is wide... in the 112-114 range.... to keep the MAP sensor stable at the lower RPMs for stability in the EFI system. The lobe shape has little to do with that, so don't get hung up on ideas about the XFI lobe being particular in that regard.

Your desire to not give away a broad performance envelope will drive you smaller durations, not larger ones. Your car driving description wants a very broad torque curve that reaches well down towards 2K RPM, and puts much less emphasis on peak HP. (But you will get good power from your breathing parts on your engine anyway. 'Drag race' grinds are not what you want.

The duration spread has more to do with the valves and ports in the engine and little to do with RPM range or being EFI or carb.

All good points, and something I was aware of. Below is a dyno sheet from ATK's 408 create engine, the cam specs are 229/233 @050 .520in/.515ex 110LSA. I found it to be a shelf Howards Cams grind with using a 1.5 ratio rocker. Their website states a 1.6, so maybe they have a custom grind? Anyway, by using the 1.6 on the shelf cam the lift goes to .555/.549 which would be fine with the extra flow from the TFS heads. With the springs being rated at .650ish lift, not a spring killer, as long as the pressures match up. I have considered using this cam, but like many wondering if there is something better. The torque curve on it is very street friendly, and I would think, a blast to drive. The counter part to this cam would be the custom cam that Brian at IMM recently used. It used [email protected] on the intake with 580ish lift IIRC. I'll have to talk to him about that one though.

 

[rumblefish360]

That is a street friendly cam.
The curve looks good. That other cam Brian has/or speced, that would great with the right converter and gear. Love the lift spec taking advantage of the heads flowing ability. That would make a for a really nice street machine.

 

[yellow rose]

I'm still trying to figure out what a Chevy lobe is, and a Mopar lobe is. Ford lobe anyone? Specifically, where's a diffinitive chart, or data....something credible.... that shows duration at .200", .050", etc...
and lift of said lobe that shows when the lobe becomes either that dreaded god awful Chevy lobe or the awesome almighty Mopar lobe? Seriously, the Chevy lobe nonsense is tiresome. Slow ramp lobe up to very fast and everything in between. Choose your specs accordingly.

It's not all nonsense. It's pretty math specific. A Chevy lifter is .842 diameter, a Ford is .875 and the MoPar is .904, so that's where the lobe difference comes in.

The bigger the lifter, the more lift per degree of rotation you can have. And it is a case where most of the time, (again...MOST of the time so someone doesn't come along and try and stir ****) you are better off with a faster lobe.

Why? Because you can cut the seat duration way down, still get the at .050 timing you need for your application.

If you are building milquetoast stuff then it mostly may not matter. Even then, I can't see why you'd not take advantage of the bigger lifter.

That's why you don't see many Chrysler's in some of the circle track crap out there. You have to run an .875 lifter. So why bother. In fact, before NASCAR went back to roller cams, they had lifter diameter rules (everybody got stuck with the .875 lifter) and bore rules (Chrysler could easily go 4.200-4.220 while a Chevy at 4.185 was maxed out...so everybody got the 4.185 bore size) and rules upon rules upon rules.

 

[DrEamer]

That is a street friendly cam.
The curve looks good. That other cam Brian has/or speced, that would great with the right converter and gear. Love the lift spec taking advantage of the heads flowing ability. That would make a for a really nice street machine.

If nothing else, it is a pretty well proven/ known cam, both Comp and Crane offer a version that are really close. If going with Comp, the lift gets close to .580, and the Crane .563 with a 1.6 rocker. The plus for the Howards and Crane is being able to use a regular distributor gear.

 

[rumblefish360]

The bigger the lifter, the more lift per degree of rotation you can have. And it is a case where most of the time, you are better off with a faster lobe.

Why? Because you can cut the seat duration way down, still get the at .050 timing you need for your application.

Excellent add in!

If you are building milquetoast stuff then it mostly may not matter. Even then, I can't see why you'd not take advantage of the bigger lifter.

Exactly. Then again, when the complaints start rolling in............... suddenly that mundane cam suddenly doesn’t seem so bad for that, “milquetoast” build. The cam and springs last forever.

 

[Wyrmrider]

"cam for EFI" is marketing BS
If you have DI you can design around blowing fuel out the exhaust

 

[Wyrmrider]

12
just go to any cam lobe list at any cam grinder
for example
Mechanical Flat Tappet | Jones Cams
pick a duration and compare chevy, ford, mopar
or pick a lift and see how much duration you need to get there
or

 

[Wyrmrider]

What YR said
do the math
Chrysler has longer rods than SBC, so rod angles are different and maximum piston speed is further down the bore (more crank degrees} and maximum airflow is further down yet
It is the airflow curve we are trying to maximize
so if you look at a cam spec for a Mopar and they use exactly the same camspec for a SBC you can bet the house that they are using the SBC optimized timings and just using a "gang master" where all the lobes are on the same master
and just sticking a ford or mopar core in the automated cam grinder
so you not only give up the lifter advantage you give up the efficiency of the longer rod, have more overlap than necessary because the short rod chevy requires the intake to be opened earlier- and same with exhaust close
and the long rod mopar is fussier around BDC Intake closed and exhaust open as the short rod "dwells" more around BDC so is not as fussy about valve events

 

[DrEamer]

"cam for EFI" is marketing BS
If you have DI you can design around blowing fuel out the exhaust

I suppose the cam companies can be like snake oil salesmen, they all have a kool aid to sell, you just have to figure out if you are going to drink it or not. It can't be easy to be a cam company and trying to keep making something new and improved. Then they have to promote their product whether the gains or real or mystical. That is why I am here, to learn, and avoid the kool aid.

 

[DrEamer]

What YR said
do the math
Chrysler has longer rods than SBC, so rod angles are different and maximum piston speed is further down the bore (more crank degrees} and maximum airflow is further down yet
It is the airflow curve we are trying to maximize
so if you look at a cam spec for a Mopar and they use exactly the same camspec for a SBC you can bet the house that they are using the SBC optimized timings and just using a "gang master" where all the lobes are on the same master
and just sticking a ford or mopar core in the automated cam grinder
so you not only give up the lifter advantage you give up the efficiency of the longer rod, have more overlap than necessary because the short rod chevy requires the intake to be opened earlier- and same with exhaust close
and the long rod mopar is fussier around BDC Intake closed and exhaust open as the short rod "dwells" more around BDC so is not as fussy about valve events

Now we are talking, this was my interest in the linked article. While the lifter diameter is of interest to me, I was wondering if a cam could be designed to compliment/compensate the timing events in a stroker. If so, what are those things.

 

[yellow rose]

Now we are talking, this was my interest in the linked article. While the lifter diameter is of interest to me, I was wondering if a cam could be designed to compliment/compensate the timing events in a stroker. If so, what are those things.

They can use lobes and timing to benefit a Stroker because I say Rod ratio makes a difference. So do a ton of other factors. What those things would be, I can't say for sure. That's why I always say call a company that will custome grind something for you. EFI is going to make it tough from what I know. IMO, when you are induction limited (and you are) you need to have the LSA be tighter than what you would run. From what I understand, EFI doesn't like that. That's what I'm told. That's why I'd call someone (more than one...Id call 5 or 6 and see which guy I get on the best with) and let them custom grind something for you.


Also, there is a bunch of hype by big cam grinders. One of them is when they started marketing cams with different durations for different cylinders. Snake oil.

Also...look at what Comp offers for "street" solid roller cams. Most of them are nothing but hydraulic roller lobes that they use a tight lash on.

So there is some marketing monkey motion out there. The biggest being the 110 LSA as the de facto number. It's wrong for most everything except Comps bottom line.

 

[nm9stheham]

"marketing monkey motion"......

Is that trademarked or can any of us use that phrase? LOL

 

[DrEamer]

They can use lobes and timing to benefit a Stroker because I say Rod ratio makes a difference. So do a ton of other factors. What those things would be, I can't say for sure. That's why I always say call a company that will custome grind something for you. EFI is going to make it tough from what I know. IMO, when you are induction limited (and you are) you need to have the LSA be tighter than what you would run. From what I understand, EFI doesn't like that. That's what I'm told. That's why I'd call someone (more than one...Id call 5 or 6 and see which guy I get on the best with) and let them custom grind something for you.


Also, there is a bunch of hype by big cam grinders. One of them is when they started marketing cams with different durations for different cylinders. Snake oil.

Also...look at what Comp offers for "street" solid roller cams. Most of them are nothing but hydraulic roller lobes that they use a tight lash on.
So there is some marketing monkey motion out there. The biggest being the 110 LSA as the de facto number. It's wrong for most everything except Comps bottom line.

As far as the EFI goes, Edelbrock recommends a minimum of 8 inches of vacuum at idle, and have a 3 settings for cam based on duration. It seems fairly forgiving to a point, but I want to keep the duration under [email protected] for good measure. I am spending some time on their forum to see what other users are running for cams.

What is interesting is Comp uses 114 lobe separation and 8 degree duration separation on the linked cam. I'm not sure if it has more to do with it being a stroker cam, or that the XFI lobes require it. The research continues.

 

[rumblefish360]

I suppose the cam companies can be like snake oil salesmen, they all have a kool aid to sell, you just have figure out if you are going to drink it or not. It can't be easy to be a cam company and trying to keep making something new and improved. Then they have to promote their product whether the gains or real or mystical.

BINGO!!

 

[rumblefish360]

Right on!

They can use lobes and timing to benefit a Stroker because I say Rod ratio makes a difference. So do a ton of other factors. What those things would be, I can't say for sure. That's why I always say call a company that will custome grind something for you. EFI is going to make it tough from what I know. IMO, when you are induction limited (and you are) you need to have the LSA be tighter than what you would run. From what I understand, EFI doesn't like that. That's what I'm told. That's why I'd call someone (more than one...Id call 5 or 6 and see which guy I get on the best with) and let them custom grind something for you.


Also, there is a bunch of hype by big cam grinders. One of them is when they started marketing cams with different durations for different cylinders. Snake oil.

Also...look at what Comp offers for "street" solid roller cams. Most of them are nothing but hydraulic roller lobes that they use a tight lash on.

So there is some marketing monkey motion out there. The biggest being the 110 LSA as the de facto number. It's wrong for most everything except Comps bottom line.

 

[rumblefish360]

What is interesting is Comp uses 114 lobe separation and 8 degree duration separation on the linked cam. I'm not sure if it has more to do with it being a stroker cam, or that the XFI lobes require it. The research continues.

The wide separation is for the computer. The 8*’s more exhaust duration is a popular thing to use. What you need maybe different. Remember, there grinding the cam that way for a wide audience and less trouble for the wide verity of end users that can’t tune the computer.
In general, the cam will work and probably pretty good. If you sat down with someone that had a dog in the game, everything would change. Say for example, Comp sponsored you. There parts would be second to none they sell and there cam finders would have more than a basic telephone tach guy working on Your engine to search for max return.

Your 232* duration just simply puts the operating hand at a certain point to start. Where it ends is another story based on the part on the engine.
After that, the court is WIDE OPEN to how everything else is being done. And that’s a huge field.

Back to the split duration....

It should be designed to get all of the exhaust out effectively and efficiently without loosing power while still having the ability to help (Along with the exhaust) fill the cylinder when the intake valve opens. Huge gains and losses are here. For a stroker, the ability to fill and extra 40 cubes or 6 cubes per cylinder should be just a minor adjustment but it is t due to the mystery of the actual quality and flow of the intake and exhaust tracks. If that was scientifically know, it would be easier.

For any grinder, there generalizing for the masses.
And hence, the reason why you have cookie cutter cams.

 

[Wyrmrider]

on the EFI part of the question
what kind of EFI
throttle body
port
common pulse
sequential
DFI?
Whatever, most are going to have the LCA spread out except maybe the DFI
however as to special lobes? snake oil

as rumble just said exhaust duration depends on lots of factors
open headers versus mufflers vs stock manifolds just for openers
your exhaust head flows
and the rod length which is longer than a chevy (we can both do custom)
but 8 degrees is getting to be "old school" with ported or modern heads

232 degrees duration- more snake oil
.050 timing is really only useful for degreeing your cam unless you are comparing the same series from the same grinder as "intensity" and therefore real seat timing varies all over the map

If comp sponsored I'd use a different grinder and a comp decal for a MOPAR

 

[Krooser]

I have been burning the midnight oil trying to figure out a cam for my 408 build. I stumbled onto the linked article , which made a lot of sense since my build is somewhat close to this in many ways. The cam is for a Ford small block, but it would seems like they could put it on a Mopar core. I might settle for a little less duration, but the theory seem sound.

Street Stroker 351W Gets a COMP XFI Cam

You don't want a Ford XFI lobe on your Mopar you want a lobe designed for a .904 lifter. Big difference.

Speak to an expert not a guy who answers the phone... Call Jones or Bullet or another of the custom cam guys. A custom Jones solid flat tappet is $238 IIRC...peanuts in the scheme of things.

 

[yellow rose]

As far as the EFI goes, Edelbrock recommends a minimum of 8 inches of vacuum at idle, and have a 3 settings for cam based on duration. It seems fairly forgiving to a point, but I want to keep the duration under [email protected] for good measure. I am spending some time on their forum to see what other users are running for cams.

What is interesting is Comp uses 114 lobe separation and 8 degree duration separation on the linked cam. I'm not sure if it has more to do with it being a stroker cam, or that the XFI lobes require it. The research continues.

Interesting. So as long as you have 8 inches of vacuum the EFI won't care? If that's the case, that should be easy.

Did you ever post your heads and intake manifold??? Because 232 at .050 unless your heads are well prepped W2 or better is going to put peak power at 5200. Maybe. And that to me is a waste.

Again, this points back to a custom cam. And I can't see the 114 LSA ever unless you have a killer set of heads. But Comp and I (and many others in the cam world) will never agree on the LSA issues.

 

[DrEamer]

on the EFI part of the question
what kind of EFI
throttle body
port
common pulse
sequential
DFI?
Whatever, most are going to have the LCA spread out except maybe the DFI
however as to special lobes? snake oil

as rumble just said exhaust duration depends on lots of factors
open headers versus mufflers vs stock manifolds just for openers
your exhaust head flows
and the rod length which is longer than a chevy (we can both do custom)
but 8 degrees is getting to be "old school" with ported or modern heads

232 degrees duration- more snake oil
.050 timing is really only useful for degreeing your cam unless you are comparing the same series from the same grinder as "intensity" and therefore real seat timing varies all over the map

If comp sponsored I'd use a different grinder and a comp decal for a MOPAR

The EFI will be Edelbrock's Pro Flo4, so sequential port EFI. I found some information on their forum today, some of the guys are running 110, but one of the more knowledgeable members said 112 or more works better. Thanks for the continued input.

You don't want a Ford XFI lobe on your Mopar you want a lobe designed for a .904 lifter. Big difference.

Speak to an expert not a guy who answers the phone... Call Jones or Bullet or another of the custom cam guys. A custom Jones solid flat tappet is $238 IIRC...peanuts in the scheme of things.

I have about had it with Comp anyway, the kid that I have been dealing with really needs to learn to listen to what I want, not just offer the lamest box cam because it is easy. I have a submission into Bullet, and may do Jones as well.

Interesting. So as long as you have 8 inches of vacuum the EFI won't care? If that's the case, that should be easy.

Did you ever post your heads and intake manifold??? Because 232 at .050 unless your heads are well prepped W2 or better is going to put peak power at 5200. Maybe. And that to me is a waste.

Again, this points back to a custom cam. And I can't see the 114 LSA ever unless you have a killer set of heads. But Comp and I (and many others in the cam world) will never agree on the LSA issues.

Heads are going to be Trick Flow 190's, Edelbrock uses a Super Victor EFI on their system. Everyone that has used so far the it said they had better throttle response then the duel plane carbs, or TBI systems that they had replaced. I do need a little more vacuum, since I am running power brakes. read my response above, I'm talking to custom cam guys soon!

 

[Matts440]

Dont forget Shane at crower to talk to him, he did my custom cam for my build plus many others. Great guy as well.

 

[DrEamer]

So, I have filled out online cam recommendation forms from Crower, Bullet, and Jones cams. The forms were interesting if nothing else. I found it interesting that Jones and Crower both asked for head flow numbers, but Bullet did not. Then Jones and Bullet asked for spring pressures, but Crower did not. Comp on the other hand asked for neither. I will be interested in see what they all come up with.

 

[rumblefish360]

Spring pressure?
IMO, a moot point on a fresh build or serious upgrade in cam. But there is merit in it.

 

[RustyRatRod]

I'm still trying to figure out what a Chevy lobe is, and a Mopar lobe is. Ford lobe anyone? Specifically, where's a diffinitive chart, or data....something credible.... that shows duration at .200", .050", etc...
and lift of said lobe that shows when the lobe becomes either that dreaded god awful Chevy lobe or the awesome almighty Mopar lobe? Seriously, the Chevy lobe nonsense is tiresome. Slow ramp lobe up to very fast and everything in between. Choose your specs accordingly.

Like rumbleness said, it's all about the lifter diameter. In other words, the larger the lifter diameter, the more lift per a given duration that lifter can stand. Make sense? Sometimes though there are situations where you actually WANT a Chevy or a Ford lobe on a Mopar camshaft. It's all dependent on what you're doing. Say for instance you're running a large by huge solid roller on the street and you want it to last, rather than wear out the valve springs or the rest of the valve train. In that instance, you're not lookin for every ounce of power. It's probably gonna make a pile anyway, so if you're not racin for money, you want that expensive stuff to last a while, so you choose a lobe that's less aggressive "to a Mopar". Conversely, you may want something that's on the ragged edge of everything in the world and if that's the case, you're probably racing for dough and want to spank everything out there, so you choose the lobe best designed to the Mopar lifter diameter to do that. Chevy especially does not have that advantage, because they cannot stand a Mopar lobe with a ton of lift without ill effects. Mopar has the best of both worlds, because we can pick and choose lobes from any domestic lifter diameter we want to accomplish a given objective. Did any of that make sense?

 

[RustyRatRod]

I’ll say NO to the resounding exclamation and excitement of others. Here is why, build your engine, dyno it, if it lacks HP up top, the next size cam is what you need to achieve your goal. Not enough torque down low? The next smaller cam is what you need.

Unless you have more information that needed about your engine vs a rocket launch to the moon, any choice you make will more than likely be a good one. However to maximize the engine, start with the cylinder heads port flow balance and work on the cams lobes to get the most on what your endeavoring to achieve.

I would start with a top of the line computer sim that has more parameters than simple head flow numbers. Tighten up your belt, it’s going to be a heck of a learning curve and your information list is going to get long.

I agree with this. All I would do is what I outlined. Choose a cam based on the cubes and let er rip. You start trying to pick a "stroker specific" this and that and you're gonna end up with a project that's not gonna get done for a while, because you're trying to grasp all of the info that's probably splittin too damn many hairs anyway.