Mild 6.0L Build Suggestions?

[Matthew Jeschke]

That's the low lift version of the first cam I had in my 6.0. Awesome cam I recommend it for anyone 4.8, 5.3, and 6.0 because it works great and doesn't lose anything anywhere, and is probably the best option for MPG. But......... I think it misses out on some top end power.

What was the lift on the cam you had used?

I'm thinking I cannot get low end power and high end as well w/o loosing gas mileage? The duration has to be wider to gain power up top? Then the overlap increases and air doesn't enter the cylinder as well when both valves are open at low rpm?

I think I'm starting to get the hang of this camshaft spec thing haha

Also whatever cam I get I think I'll get a bit better performance out of it with these Johnson lifters. They are a slow leakdown design. I believe they'll oil fine at lower RPM (although a bit concerned about that). They are designed to no collapse and maintain a high seat pressure. https://johnsonlifters.com/Products/HydraulicRollerLifters/2116LSR.aspx

I found a set for $325! Snagged em, *ahem* although they are low mile / used so I'll have to give them a REALLY close look when I get them. I know isn't kosher to use used lifters.

 

[iamdub]

This comp cams one looks interesting...


https://www.lsxceleration.com/comp-...-strong-mid-range-power-good-performance-cam/


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Almost identical to my cam, just has less lift. I don't know how my TSP Stage2 lobe profile compares, but a quick Google search showed the Comp XFI lobes to have more aggressive ramp rates, which is why they get away with lesser lift. To put it into perspective, they snap open the valves more quickly to their full lift then close them more quickly. "Softer" lobes open the valves more gradually. If you could put it into a graph, the XFI lobes sharply beginning their lift and reaching their max lift then the same quick action on the closing side would create a tabletop looking line, like a "mesa". A softer lobe profile would be more gradual to the peak then curve back down like a gentle hill. The more aggressive ramp rate opens the valve sooner, so it starts letting air in a little sooner. This lets more air volume in with less lift over a given amount of time. By comparison, the softer (less-aggressive) ramp rate doesn't open as much as early so it needs to open more (more lift) to let that air volume in. The aggressive ramp/lobe profile could benefit something like a high compression/tight quench setup where PTV clearance is a concern, but the trade-off is additional valvetrain stresses and harmonics. By "valvetrain", I'm including the lifters. The softer ramp/lobe profile would be easier on the valvetrain. There's a lot more to this that reveals additional pros and cons of each, especially intended operating RPM.

 

[iamdub]

I'm thinking I cannot get low end power and high end as well w/o loosing gas mileage?

For mileage, the general idea is to have a cam that boosts torque at the intended operating RPMs. For example, with my 4L60E, 3.73 rear gears and 32" tires, I'm in the 1,700-2,000 RPM range at highway cruising speeds. My cam really starts to show it's mid-range power around 2,000 RPM and whatever percentage of throttle that entails (when cruising at a steady speed). So, compared to stock, my engine is making more power at that RPM, requiring less throttle input, which equates to more efficiency, which means more MPG. The compression is a considerable factor as well and plays a role in the cam selection. If a cam costs a little dynamic compression ratio down low due to overlap or tighter LSA, you can raise the static compression ratio to counter this as well as boost power across the entire rev range. This is why I'm a fan of running as high of compression as you can afford in timing, tuning and octane rating.

 

[Matthew Jeschke]

I keep going back to the sloppy stage 2 cam. That dyno graph from holdener showed it building power cross the entire RPM. I watched this dude give 2 hour lecture on specing cams. he basically describes SS2 :/

hrm... decisions decisions decisions haha

I wonder if I am leaving anything in efficency on the camshaft table. I would be stoked if I could push my tahoe up a hair from 17 mpg..

Reading more and more on this. I think I see a cam that increases operating range torque is what I need? A cam that gives more power at highway speeds and below. The more the better, but any more is better than before?

Then it is all in optimizing the tune and rest of car? I recall my camaro build, I put in a big cam. raised idle to 1000 rpm, got a ****** tune. my mileage on highway fell by a 2 or 3 mpg. However I also deleted the EGR which I wonder if that effected it? My in city MPG got way better with that build. Later on I installed an electric water pump, smaller crank pulley and all of that too.

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[Matthew Jeschke]

That's the low lift version of the first cam I had in my 6.0. Awesome cam I recommend it for anyone 4.8, 5.3, and 6.0 because it works great and doesn't lose anything anywhere, and is probably the best option for MPG. But......... I think it misses out on some top end power.

Missed your comment... I am looking at the lobe profile. I see what they are doing. They are decreasing overlap but making a very aggressive ramp up have an overall greater volume of air flow. I wonder if thet decreases the life of the valve train at all? It's not as gentile as a traditional lobe. I wonder if there's much data out there on how long these last? I cannot seem to find any reviews other than one by Richard Holdener for 54-469-11 which is an absolutely massive beast cam and only a dyno test.

I see Comp Cams has a whole series of towing camshafts for the 6.0L, most claim great MPG. I wonder if this isn't my solution, one of these HERE

 

[Dantheman1540]

@iamdub great info! I really haven't ever dug into ramp rates and lobe design.

I'd say getting over 17mpg in a Tahoe with a 6.0 is going to be difficult without maximizing the wheel and tires combo for minimal drag, weight, and rotating mass while also silencing out the gear ratio.

Tune has a huge part to do with MPG and it takes considerably more time to dial in the part throttle tuning than it does WOT or idle. There are also some theories on Lean Cruise techniques and other things to help with MPG. Additionally some tuners turn off things like deceleration fuel cutoff (DFCO) because it messes with fuel tuning but they never turn it back on which means during deceleration you will be wasting gas.

I would 100%say lobe ramp up has an effect on reliability but I feel proper springs are more important.

All of those are pretty small and I'm sure would net good mpg just because they aren't wild and would produce gains at the regular driving rpm not 6,000. I really liked the 212/218 high lift it's the same one DUB has I believe and I'd guess is the most recommended cam out right now. It's also a great cam for boost later down the road.

Also for MPG I'd suggest high completion ration with maximum quench so you can run more timing and have a higher threshold for knock.

 

[Matthew Jeschke]

forgive my noice what is high completion ration with maximum quench?

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[wjburken]

forgive my noice what is high completion ration with maximum quench?

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https://help.summitracing.com/app/answers/detail/a_id/4941/~/engine-quench

 

[Matthew Jeschke]

@iamdub is this your camshaft HERE if so how do you like it? Seems reasonably priced Which one did you get the 112 or 114 LSA?

@wjburken thanks I had thought it might be something like that. Never heard that word quench used before. Pretty big green horn here haha I build a motor like once a decade.

 

[iamdub]

@iamdub is this your camshaft HERE if so how do you like it? Seems reasonably priced Which one did you get the 112 or 114 LSA?

@wjburken thanks I had thought it might be something like that. Never heard that word quench used before. Pretty big green horn here haha I build a motor like once a decade.

Yup. That's mine. I have the 114 LSA. Didn't have a choice since the cam was offered to my by a friend for $100. I really like it for my purposes. Not too wild to sacrifice anything that I can tell and, through the idle tuning, was able to make it lope like a little bit larger cam. Haven't been back to the track yet to compare it to stock, though. As far as MPG, I get ~1-3 miles per gallon MORE than I did with AFM, depending on cruising speed. I average 20-22 on the highway at 65-70ish.

BUT, this is on a 5.3. More cubes would need slightly more cam to achieve the same results. Look at it like this- a slightly rowdy cam in a 5.3 would be more tame in a 6.0 or larger. A rowdy cam in a 6.0 or larger would be extra rowdy in a 5.3 or smaller.