Removing injection events - compensation?

[2007 5.9]

Tried Andrew's tune on my truck....needs some adjustment for my setup. Did start easier, run quieter, but much dirtier than my DD tune. I told andrew that I will be working on it during the week and see what I can come up with.

I think we can work it out...just needs time.

~Les

[AdamRRT]

Yup I'm in the same boat, due to my larger sticks. I'm gonna clean up the DD portion this weekend. I normally hit about 50psi on a Smarty/BDTD CL tune, but on this one I'm at 38-39psi. BUT that said, I don't feel a LOT weaker. Most likely due to being in a happier place in the compressor map. I'm gonna enrich the heavy TPS portions to see if I build more boost to about 45psi.

[olboyowl]

loaded the no pilot tune back into the truck. gonna work on it more tomorrow. i added a little timing between 800-1400 to try and clean up some of the haze. will get some info up tomorrow night.

[cumminsDK]

Leaving pilot off actually makes the truck start easier. But it's more so for the principle of it, the challenge. I know there are nay sayers, but I just want to see if I can make my theory work in my head.

Also, if we were to switch to a cam where the lobes aren't ground to overlap the exhaust valve when the intake starts to open to leak exhaust gas back into cylinder like Cummins did to pull off the in-cylinder egr, would we need to do anything to post?

I think you will find "valve overlap" in any cummins b series built since at least 1989. Also duramaxes, and John Deere engines dating back to the 404 in the '60s. Its not for in cylinder EGR

[2007 5.9]

I think you will find "valve overlap" in any cummins b series built since at least 1989. Also duramaxes, and John Deere engines dating back to the 404 in the '60s. Its not for in cylinder EGR

True to a point...CR engines has THE MOST valve overlap of any Cummins B-series engine, for the simple in-cylinder EGR effect they needed to not have to go to the external EGR you have seen in the ISX, ISL, QSX etc... and the B-series 6.7.

When i swapped my cam, I noticed cleaner oil and cooler oil temps....

~Les

[cumminsDK]

True to a point...CR engines has THE MOST valve overlap of any Cummins B-series engine, for the simple in-cylinder EGR effect they needed to not have to go to the external EGR you have seen in the ISX, ISL, QSX etc... and the B-series 6.7.

When i swapped my cam, I noticed cleaner oil and cooler oil temps....

~Les

i have been researching this and haven't been able to locate any info to confirm, and for that matter anything describing the amount of overlap on any cam....not to say you are wrong, just that valve overlap has always been there to some degree without being for the purpose of EGR. i would be interested to have a read on something giving info on the amount of extra overlap on the CR's for the purpose of in cylinder EGR. this would make sense as cummins has always found simple ways to meet emmissions requirements ahead of time without a lot of extra parts or systems.

[AdamRRT]

I still can't fathom overlap on a boosted engine helping to burn EGR gases. If the exhaust valve is open at the same time the intake valve is, you'll have the boost blowing it straight through. Now opening the exhaust valve only then the int valve, may do it. But overlap is normal for making power cause it allows the exhaust pulse to pull the intake charge in at higher rpm (NA engines), and greater cylinder filling velocity due to that flow through (boosted or non).

[DoghouseDiesel]

You're thinking overlap in the wrong way.

What it does is CLOSE the exhaust valve early trapping the exhaust gas and bringing it into the next intake stroke.

And yes it is there.....3rd Gen OEM cams SUCK!

Here are the cam profiles from the various generations. Specifically, look at the lob seperation angle (LSA).

The 24v VP44 trucks had a much better cam than the CR trucks do.

12V Stock:
INT: 159° @.050”.235” Lift
EX: 204° @.050” .263” Lift
102* LSA

24V Stock:
INT: 159°@.050” .235” Lift
EX: 206° @.050” .297” Lift
107.5* LSA

24V 3rd gen:
INT: 163° @.050” .237” Lift
EX: 191° @.050” .299” Lift
98.5* LSA

[FUBAR]

Thanks for the hard numbers Rich. But either way, like you said it, stock 3rd gen cams suck.

[cumminsDK]

You're thinking overlap in the wrong way.

What it does is CLOSE the exhaust valve early trapping the exhaust gas and bringing it into the next intake stroke.

And yes it is there.....3rd Gen OEM cams SUCK!

Here are the cam profiles from the various generations. Specifically, look at the lob seperation angle (LSA).

The 24v VP44 trucks had a much better cam than the CR trucks do.

12V Stock:
INT: 159° @.050”.235” Lift
EX: 204° @.050” .263” Lift
102* LSA

24V Stock:
INT: 159°@.050” .235” Lift
EX: 206° @.050” .297” Lift
107.5* LSA

24V 3rd gen:
INT: 163° @.050” .237” Lift
EX: 191° @.050” .299” Lift
98.5* LSA

Actually he's thinking of it right when 1 it's at TDC of compression both valves for 6 are open hence valve overlap so exhaust doesn't close early.now a far as boost pressure blowing the exhaust out of the cylinder remember to have boost we also must have drive pressure with 1:1 being ideal some turbos are as much as 3:1 so drive pressure would keep exhaust in the cylinder