NAVYBLUE210

Member/friend of mine 64Post had that combo, 347,ported 243s,Titan 4, ~11.0:1 comp, but with a short runner snyper intake
in a Fox with turbo 350 ~2200 stall, & 3.55s, Ran GREAT!
The TBSS will run even BETTER!
I would guess 425-450 RWHP depending on driveline.
Torque every where and pull to 6500+

CAMMOTION PERF

Here is a couple graphs for the tech fans to think about. I have had a few people over the years argue that there is no reason to cam a rectangle port engine different than a cathedral port engine. Well, as you all know, I think there is. And that is why our cams are different.

Comparison #1
6 liter LY6 short block
706 heads
TBSS Intake
2" American Racing Headers (Our dyno headers)

Comparison notes. Very similar cams. One is 111+4 and one is 113+4. I am not looking at the LSA here, I am looking mostly at overlap and intake valve close timing (IVC). Titan 4 LS1 has a 42.5 degree IVC and 3.5 degrees of overlap. The HotRod cam has a 40.5 degree IVC and 10 degrees of overlap. Notice how the HotRod cam pretty much outperforms it everywhere, even at high RPM. With an earlier IVC and less lift, one might expect this cam to perform better at lower RPM like it did, but may not has expected it to outpower the Titan 4 at high RPM. But the HotRod did outperform the Titan 4 at high RPM. That is the overlap talking. Now, some might be tempted to wonder why anyone would choose the Titan 4 over the HotRod cam? Drivability. Even on the dyno, the idle quality of the Titan 4 was very noticeable. And, when you drive them, the Titan 4 is a much smoother experience. This is where a trade-off decision must be made. Do you want a nasty idle and all the power, or do you want manners better drivability?

HotRod LS cam (227/237 111+4 .595"/.587")
vs
Titan 4 LS1 Cam (227/232 113+4 .612"/.595")



Now for the 2nd comparison:
6 liter LY6 short block
823 heads
Truck Intake
2" American Racing Headers (Our dyno headers)

Comparison notes: Notice how much less advantage the HotRod cam had in this test compared to the cathedral port test. Is this a perfect comparison test? Nope. But, if you look, there is still something to be learned. Since I get to see a lot more test, I will share with you that, in general, the bigger heads did not need as early of an IVO to perform. And, generally, this means less overlap. Know that you can have more power with less overlap and better drivability with a better flowing head. The cam/head/intake relationship is real. Pick the right cam.

HotRod LS cam (227/237 111+4 .595"/.587")
vs
Titan 3 LS3 Cam (227/237 113+3.5 .621"/.604")

G Atsma

That is a great test! Overlap carries it to the top, PLUS low and mid range. That was my point about the truck cams, only there, the low duration still allows a very good stock-type idle. You pointed that out about the Tooley cam I brought up, but I bet it holds true for your 4.8 Stage 2 truck cam with a 202 intake duration and 31 IVC. I think you would see low end gains if the LSA were narrowed to 112 and advanced 2 degrees to keep the 31 IVC. I love playing with Summit's cam calculator... lol

CAMMOTION PERF

Then you would love hanging out with us on the dyno days! We work crazy hard and fast, but we love every minute. In fact, we have a video of us changing a cam in 10 minutes and 20 seconds. I was able to do one myself in just over 20 minutes.

I am glad you enjoy the Summit Camshaft Calculator. If you notice, that was contributed to them by Cam Motion!

~Steven

RedXray

I last year I ran the "Little Chopper" in my LQ9 RCSB 3,200 stall truck and that little somebitch would pull strong to 6000 RPM. Went to aftermarket heads and needed a different cam that would turn more RPM's with a later IVC. Just because the chopper sounds good doesn't mean it can't run good with the correct stall and gear set.

The Little Chopper had better low to mid range power than the Sloppy Stage 2 it replaced. I thought going from a 112* LSA to 108* I'd have to do a lot of tweaking in the tune but the chopper fired up and idled great on the SS2 tune. A few VE and MAF data logs was all it took to get the chopper tune squared away. I think it's a great cam for a mild 5.3 or 6.0 build... that is if you can handle the cool sound

G Atsma

I KNOW I would!! You NEED to post that video! Gearheads Unanimous would owe a ton of gratitude!
Yeah, I knew that. Summit gives credit to you for that.
I like to see how much cam I can spec without going more than 35 IVC or less than -20 overlap, both of these specs from the TruckTorque cam.

Z28SteveA4

iTrader: (16)

So this might be a dumb question but goes out to cam motion. How much does lift really play a roll with these cams? I understand it has to do with headflow and valvespring wear but lets take the titan 4 cam (227/232 113+4 .612"/.595") instead of the lift you have. What would happen if the lift was dropped down to .570/.570 or raise to .630/.630? Keeping the same durations. I guess more or less how do you come up with the lift for intake and exhaust? And how much will it’s effect the performance going lower or higher with lift?

G Atsma

I've wondered about lift myself. Looking forward to CM's reply....

CAMMOTION PERF

Actually, this is a very good question. And, it is kind of a big question. It is a big question because the answer is straight forward but not simple. It speaks to what I will call the lift duration relationship.

When we talk about duration these days, mostly people are referring to the "duration" in crankshaft degrees at .050" lobe lift. That means that, as you rotate the engine, you start measuring crankshaft degrees of rotation once the camshaft has raised the lifter to the height of .050". You continue to measure the crank's rotational degrees as the lifter goes past .100", .200", .300" etc all the way to peak lift and then back down until your reach .050" of lifter lift.

While that is the most common way to discuss or specify the "duration" of a camshaft, you can also specify duration at .006", .100", .200". 300" or even .400". I tell you this because higher lift durations can and most often are affected by total lift. For example. Say you have a camshaft lobe that is 232 degrees of duration at .050" with .350" lobe lift (.595" valve lift with a 1.7 rocker arm ratio). That lobe may have a .200" lobe lift duration with as little as 148 degrees. Now look at another lobe that is 232 degrees of duration @ .050" that has a lobe lift of .383" (.650" valve lift with a 1.7 rocker arm ratio). This lobe could have as much as 155 degrees of duration at .200" lobe lift. The disparity between these two cams will be even greater at .300" lobe lift. .200" lobe lift is .340" valve lift with a 1.7 rocker arm ratio. .300" lobe lift would be .510" valve lift with a 1.7 rocker arm ratio.

So, if your head flow is 220 cfm at .340" and 280 cfm at .510" lift, you can see having the valve spend more time in these higher lift areas of the lift curve will allow extra air flow that will make more power. Many people think that if their head flow does not increase past .600" of lift or whatever number, there is no reason to have a camshaft with more lift than .600" etc. This is wrong thinking. While your head may not increase in flow past .600" of lift, it is likely doing its best work between .300" and .600" valve lift. So, if you can increase the duration in that area, you are getting more of the best part of the lift curve. In many if not most cases, a lobe with higher lift will allow you to increase higher lift durations. That is, if the lobe is properly designed to take advantage of the additional lift. To clarify more, as you increase the higher lift durations, it is typically necessary to add more peak lift to maintain a good smooth lobe shape. This is an important relationship.

But wait there's more! (couldn't help myself lol) Some lobes can benefit more from additional lift than others. For example, a very long duration lobe with lobe lift such as a 265 degrees of duration @.050" lobe with .330" lobe lift will pick up a lot more .200" duration with an increase in peak lift than a shorter duration lobe like a 226 degrees of duration @ .050". This is because there is only so much lift you can put on a given duration until the acceleration and deceleration rates become too high to control. Also, there is only so much higher lift duration you can put on a lobe with a certain valve lift. The lift to duration relationship has direct impact on stable lobe design.

Now that I have told you this, I will give you advice that I give out almost on a daily basis. DO NOT TRY TO PICK A SUPER AGGRESSIVE LOBE TO MAKE POWER. Instead, pick a lobe that fits your valve-train's capabilities and then pick the proper cam specs (valve events) that are needed to tune your combination to the desired RPM range and performance characteristics. Countless people have tried the more aggressive lobe mindset only to be served up disappointment and a pile of broken parts. And, this is not just the inexperienced either. Lots of big time engine builders try this too. The key is to find a lobe the will take advantage of your valve train's capabilities, but also afford you reliability and longevity. For LS guys, you have it easy. Our XA hydraulic roller lobes will make great power and remain stable in most any LS combination to 7500 RPM with a modest valve springs and a stock rocker arm. This has already been thought out for you. No need to try to re-invent the wheel. Instead, stay focused on getting the right specs and valve events. That is where your focus and energy will pay off.

So, can more lift equal more power? Maybe. If the lobe design can benefit from it. If the valve train can handle it. And, if the valve events are chosen correctly.

wannafbody

iTrader: (2)

Which is more important overlap, LSA or intake/exhaust split?

NSFW

IMO the top two are overlap and intake valve closing angle.

I'm pretty sure the numbers we use to characterize cams were designed by people who operate cam grinders, because those numbers suit their needs perfectly. But translating them into numbers that have (relatively) simple relationships to actual engine performance requires doing math on those numbers. So it's just a poor decisions that led the whole industry to use those numbers in product naming and marketing materials.

The "III/EEE @ LSA +Advance" thing, as a naming convention, is just stupid. (Yes, it is. Fight me...) I mean sure, it makes sense for the person setting up the cam grinder, but for customers and engine builders, it's just dumb. It's like using inches, feet, and pounds decades after the metric system was invented.

It'd be nice if an industry leader took it upon themselves to lead the industry to a better place, by putting meaningful numbers first (overlap, IVC, maybe a couple other events) and then following those with the old-school convention just as a footnote.

I won't mention any names, but I'm pretty sure one of those potential leaders is nearby, perhaps even listening...

biketopia

iTrader: (5)

Thanks Cammotion, lots of really good info in here and I'm trying to soak up a lot of it. Maybe I missed it but I believe you said you ground a new truck cam, was that just for the square port heads? I have a 2x4 2500 and was looking at your cam's and one of summit's truck cams. Not looking for max effort, looking for power under the curve to use the truck to do truck things.

JimMueller

iTrader: (9)

I've got your Torquey Stroker in a 418, but I'm looking for more tq between 3000-4000 wo a big sacrifice above 6000 for hpde's. I'd love to see a comparison of the Rect TS vs Rect Titan 3 between 3K and 7K.

BCNUL8R

iTrader: (2)

Funny how the small cam guys think that tiny bit more TQ they have at low rpm means they’ll beat everyone stop light to stop light.

Like gears, converter, tires, suspension, and driver can’t make up for that tiny low rpm torque advantage and put them in an rpm range to take advantage of the huge power advantage they made in higher rpms.

It’s about the combo and these dyno results should help someone pick the correct converter, gears, etc for the cam they are using.

Darth_V8r

iTrader: (4)

IMO, LSA and split are just results of the math. Between the three you've listed, I'd say overlap, because that's the only one of those three I set on purpose:

When I look at cam specs, first thing I look find/set is IVC, which is based on displacement and desired RPM range. Second is compression ratio, which is set based on IVC and lowest quality fuel that will be used. Third is EVO, which I tend to set based on compression and driver's requested RPM range.

Then, I use IVO and EVC to set overlap. Higher rpm range or increased carrying power past peak, I increase overlap. Improved drivability, I decrease overlap. Driver wants more of the torque down low, I bias the overlap to the intake side. Example: IVO at 7, EVC at 3 for 10 degrees intake-biased overlap. Driver wants the torque to come in later, I bias the overlap to the exhaust.

Sorry for the long-winded answer. The intent is to show that I will mess around with valve events to deliberately set overlap where I want it. LSA, "advance", and split will simply just be what they are at the end of the day. I put advance in quotes, because I don't look at the "+4" on a cam spec to call it advanced. If the overlap is intake biased, I see the spec as advanced. if the overlap is exhaust biased, I see the spec as retarded. If the overlap is balanced, I see it as "straight up".

Darth_V8r

iTrader: (4)

This one statement right here says a lot about what goes on behind the scenes. Very often you are working with expectations that are not based on real results.

Darth_V8r

iTrader: (4)

That might be the gold nugget of this entire thread

SLOW SEDAN

iTrader: (13)

Facts! But I don't think the baby cam guys want to mess with spec'ing a converter, gears, or even race at high RPM. Personally I don't get the desire for more torque in a street car, even a 5.3 will spin slicks on the street if you have the desire.

CAMMOTION PERF

This is another "big" question. Here is how I look at it. They all matter. But, they have a mathematical relationship. Because of that, looking at it in terms of overlap vs LSA vs intake/exhaust duration ratio or split is just not specific enough as they affect one another. So, it gets messy and often leads to incorrect generalization and assumptions.

Many tech minded people in here will tell you to look at "valve events". I would recommend this too and a little more.
Here is a screen shot of the Cam Motion "Timer"

https://cammotion.com/Timers-and-Calculators

If you enter the durations, lobe separation angle and advance, it will tell you the intake valve open, intake valve close, exhaust valve open and exhaust valve close "valve events" or timing in relation to the durations you entered. It also tells you overlap. For this, most people use the duration @ .050" lobe lift, but you can enter this for durations at any lift if you want to see the corresponding valve events.

When I look at a combo, there are a lot of things I must consider before I even start with durations and valve events. Because I do such a wide range of applications, there is a lot more variation in the factors than there is in the typical stock rocker LS/LT world. For example, I might be working on something that has a full inch of valve lift. Or, perhaps drastic differences in valve and valve train weights. Or, very high or low RPM applications. But, for simplicity sake and the sake of a more simple conversation, let's say we are talking about your typical stock rocker LS build.

Once I know all the details of the engine build (displacement, head type and flow, intake manifold design, drivetrain setup, etc) I must know the desired RPM range and desired performance characteristics. Once I am armed with this info, I can start determining how I want to meet the customers needs. In general, here is a typical thought process order for me. First I will have a certain intake duration in mind. Then I will have a certain exhaust duration in mind. Next I usually think about when I want the intake valve to close. After that, I am considering the amount of overlap as it relates to desired drivability and performance characteristics. I punch some numbers into the Cam Motion Cam Timer and start looking at the IVC, Overlap, EVC in relation to the IVO and also the EVO. Once the number are in the Cam Timer, I often make little adjustments. Many times some sacrifices must be made. This typically happens when desired driving characteristics are at odds with the desired power goals. If a customer wants a smooth idle and good drivability, but also wants a big dyno number to impress his buddies, something has to give.

I look at intake duration first because I know it is going to take a certain amount of duration to make the best power in a certain RPM range. Duration, as the name implies, is time. If a head and intake combo flows "x" amount, it is going to take a certain amount of time a that flow rate to fill a cylinder with a certain amount of air and fuel. Next I look at the IVC or intake valve close. I do this because I know that if this is timed correctly, it will "tune" the engine to make peak torque and horsepower in the optimal place for a given duration intake lobe in a given combo. The IVC is probably the most influential valve event and a great place to start once the intake duration is in the ball park.

Next I will choose an exhaust duration. I look at exhaust duration in the context of how much power the engine is likely to make and at what RPM it will operate. How much power an engine makes tells us how much spent exhaust gasses will need to be evacuated. RPM tells me how much time an engine will have to expel the gasses. The higher the RPM, the faster things are happening and the less time the engine will have to fill or empty the cylinders. This is why "intake/exhaust split" is an imperfect parameter to look at if power levels and RPM are not taken into consideration. An engine making a lot of power at a very high RPM will likely need much more exhaust duration than an engine combo make less power and operating at a very low RPM. An 8000 RPM LS3 headed engine with a short runner intake manifold may have 20 degrees or more exhaust duration than intake duration whereas a truck engine with an LS3 head and restrictive and/or long runner intake that spends 99% of its life under 3000 RPM might only be given 4 degrees or less more exhaust duration than intake duration.

Overlap, like intake duration is something I think very quickly in the conversation. Overlap has two major implications. First, it has a very large impact on drivability and low speed performance characteristic. It affects idle quality, throttle response, engine vacuum and more. Second, it has a large impact on upper and high RPM horsepower. High RPM horsepower typically benefits from a good dose of overlap and drivability is typically ruined by a lot of overlap. The parameters for choosing overlap for maximum horsepower are completely different than choosing overlap for drivability. This is why high RPM, high horsepower camshafts are typically terrible in the drivability department.

Now, once the numbers are punched into the Cam Timer, I might start moving the exhaust centerline (ECL) to get the overlap where I want it. Of course, when I do this, it directly affects the exhaust valve open (EVO). So, if you have a given duration that you want to work with, you have to accept movement in one to get what you want with the other. And, sometimes I will change the durations to get valve events exactly where I wan them.

There is tons more to say about the effects of each valve event. But, if I tried to explain all the details and nuances, this post would never end. Maybe I will spill my methods out in a comprehensive, organized format someday.

This will give you some insight as to how I often start my process.

~Steven

G Atsma

For the guy with a 1500 truck with a 5.3 who tows on occasion, a cam that delivers 10-20# more torque from 1500 RPM on up serves a good purpose. It looks like CM's and Tooley's truck cams do just that, and that kind of difference MIGHT mean the difference between downshifting or not on some hills. It is NOT about the Stoplight Gran Prix....