Cold Weather Lope Tune

[cleatus12r]

Originally Posted by 907dave

I'll shoot.........I believe making a lope tune would consist of advancing the hell out of the timing @ idle to produce the white smoke and crappy idle.

Anyway, some common ways to make a lope tune involve (but are not limited to):

Increased MFD @ idle. This causes a "war" of sorts between the commanded fuel rate and the base idle speed. The higher MFD will cause a high idle but the base idle speed wants to maintain a low idle (500-750) so there's more of an on-off type idle. In my experience (which isn't much because I don't care about a "ruh, ruh, ruh" idle) this makes for the "big cam" sound better than.......

Substantially increased ICP @ idle. This will usually cause a rough idle with an intermittent "hits and misses" type of idle. Again, this is my limited experience with rough idles talking.

White smoke comes from retarded SOI. This also makes the engine considerably more quiet (works really well for quieting down the 95-97 trucks that have single shot injectors).

[907DAVE]

Ouch.......so explain to me why are mechanically injected friends can have some serious lope ? Besides their Camshaft, is it because their injector pumps have a "fixed" advance and have way too much at low RPM's?












Or is their something else going on?

[cleatus12r]

Originally Posted by 907dave

Ouch.......so explain to me why are mechanically injected friends can have some serious lope ? Besides their Camshaft, is it because their injector pumps have a "fixed" advance and have way too much at low RPM's?
Or is their something else going on?

In all honesty, I don't know what the mechanical injection guys do.

I know how I've gotten a 7.3L Powerstroke to do it but I am still very new at this so don't take my word as gospel.


I've removed the rude and uncalled for link. I didn't mean anything personally by it.

[Power Hungry]

Most lope tunes are made using ICP tables and setting them at idle so that the ICP is excessively low at about 600 to 800 RPM which causes the idle to drop off. Then you aggressively ramp the ICP from 0 to 600 RPM which then slingshots the engine back up over 800 RPM.

It's not the worst thing you could do to your engine but I will say that I have seen a couple lope tunes with almost 15 MPa in the 0 to 600 RPM range which can't be very good. It like trying to go full throttle every second.

I personally do not care for either the Lope or Smoke tunes, but people want them so we may as well provide them. We just do what we can to make sure they're safe.

Take care.

[cleatus12r]

Thank you for clearing that up Bill. I was drowning.

[Georgia Diesel]

O but bill,,,what a sweet sounding lope you can make a 6 liter do.

[Power Hungry]

Originally Posted by Georgia Diesel

O but bill,,,what a sweet sounding lope you can make a 6 liter do.

Hee hee!

[907DAVE]

Originally Posted by cleatus12r

Substantially increased ICP @ idle. This will usually cause a rough idle with an intermittent "hits and misses" type of idle.

A little off subject but this post got me thinking, I have experienced a rough idle with my single shots since I installed them and the only way I was able to smooth them out was to drop the ICP at idle to the mid 400's(normally mid 500's). This just about completely cured my issues but, was it the lower ICP that smoothed it out or was the SOI slightly retarded indirectly?

What changes indirectly when you drop or raise ICP at idle?

What happens if you have too much PW at idle, or is this even possible?

[Power Hungry]

Single shots always run a bit lower ICP at idle... usually about 3 MPa, vs 3.8 MPa for splits. I'd suspect that's what helped. The timing is usually negligible. At 700 RPM, the crank is rotating 4.2º per ms. On average, the difference between singles and splits is .3 ms (.8 for singles vs. 1.1 for splits) so the total timing difference at idle would be 1.26 degrees. Not really much in the grand scheme of things. There is also a modest change in the combustion point because of the raised ICP, but again, it's not anything significant at idle.

I suspect the rough idle was mostly from slight overfueling or an imbalance when trying to run relatively small pulsewidth values, which can often happen when ICP gets too high and the PCM is trying to cut back fuel to maintain idle speed.

Fuel pulsewidth and SOI are both DIRECTLY affect by changes in ICP. More to the point though, SOC (Start of Combustion) is affected in relation to ICP changes.

Too much pulsewidth causes an unstable idle. You can't really run a diesel lean or rich, it just makes power with the fuel you've got. More fuel and the RPMs climb. That's about it.