Slowly learning - critique my dontbsme tune

2002 RCSB Silverado. Pretty much copied the dontbsme combo
Stock unopened 4.8, Sloppy Stage 2 cam, PAC1218s
80E/HD2 with a Jake's 3200 street series converter, 4.10 8.8
Billet 7875, VSR 44mm WG, no BOV, Deka 80s
0411 PCM with 3bar MAP, no MAF

Still working through VE tuning at cruise and part throttle, but my WOT seems okay in the mid 10s.

I am still fighting a stumble on startup (more BRAF?) and some lean spikes during steady state cruise. My other "project" is working on adding some timing to all the non-boost cells as it's kind of a dog until the boost comes on. I think some added timing below 3000 would help the turbo light off sooner too. I've attached a "draft" tune with the stock timing copied over into the cells .5 g/cyl or lower, haven't tried it yet. Other than that it actually drives very nicely.

Feel free to critique. I am a total newbie at this and am open to constructive criticism.

The open loop eq ratio should not be 1.00 for every cell. It's not ideal for the computer to command stoich when the engine temp is well below 100 degrees. There is a reason that the factory have the open loop eq ratio richer as the engine warms up. Partly for emission and most engines run better when it's a little richer on cold starts. You just want it to lean itself out to stoich past 130 degrees.

Try to smooth out the VE to reduce the lean or rich spikes. The VE has pretty choppy when looking at the 3D graph.

Try the new tune with more timing and the open loop EQ set back to a more stock like table and see how it is. Also remove the 1 bar MAP channel from the logs, you don't need it.

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Originally Posted by 5FDP

The open loop eq ratio should not be 1.00 for every cell. It's not ideal for the computer to command stoich when the engine temp is well below 100 degrees. There is a reason that the factory have the open loop eq ratio richer as the engine warms up. Partly for emission and most engines run better when it's a little richer on cold starts. You just want it to lean itself out to stoich past 130 degrees.

Try to smooth out the VE to reduce the lean or rich spikes. The VE has pretty choppy when looking at the 3D graph.

Try the new tune with more timing and the open loop EQ set back to a more stock like table and see how it is. Also remove the 1 bar MAP channel from the logs, you don't need it.

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First off, thanks for your input, it's appreciated!

VE definitely needs work. Still chipping away at that.

It should be mentioned that the truck is fully open loop with no O2 sensors. Strictly using the wideband to tune VE. I will look at the OL EQ to try to richen it up for cold starts. Definitely has an issue always starting cold after a day or two.

I've since removed the 1bar MAP in the scanner it was freaking me out watching boost peak at 105kpa while the gauge went to 8psi, lol

Now that I have most of the mechanical bugs worked out I took it out tonight for some hits in Mexico. It seems to take forever to spool up and doesn't actually make peak boost until 4800. I'm wondering if that has something to do with it blowing through the stock muffler.....

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I responded to you on LS1tech. Shoot me a pm if you need some more help. there are quite a bit of things that need changed for it to run like it should.

need to do a pressure test to find all the air leaks in the plumbing

The map sensor won't tell you. And if you have big leaks it will create alot of extra exhaust gas pressure and lead to detonation and poor performance.

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Originally Posted by SeriousSN95

I responded to you on LS1tech. Shoot me a pm if you need some more help. there are quite a bit of things that need changed for it to run like it should.

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I responded there. Thanks for the help!

Quote:

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Originally Posted by kingtal0n

need to do a pressure test to find all the air leaks in the plumbing

The map sensor won't tell you. And if you have big leaks it will create alot of extra exhaust gas pressure and lead to detonation and poor performance.

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Would leaky I/C plumbing cause a slow spool? It hits hard after 4000rpm, you'd figure it'd be a dog throughout the rev range rather than only above a certain RPM.

If i am correct any kind of boost leak will cause a slower spool because u are loosing pressure from your leak. But i could be wrong

I changed around a bunch of additional stuff, mostly making PE enable more aggressive and adding in some timing .68 g/cyl and under in the diagonal "belt" of where it runs under WOT from 1200 rpm to boost. Marginal improvement but headed in the right direction. For fun I also experimented with making a "sloppier" trans brake...essentially using VCM scanner to lock the trans in 3rd while footbraking and mashing the gas. It built right around 4psi of boost stalling at 3,000 rpm and 20 degrees of timing. I wonder if adding a couple degrees will help it get up on boost more as it didn't want to go any higher. Letting it kick back into 1st and releasing the brake made for either a hell of a holeshot or boatloads of wheel spin.

Fun evening!

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Try pulling timing to get it on boost when doing your pseudo trans brake trial

I'm actually going to try adding some timing using the VCM scanner while using the sloppy brake to see if it helps it spool up. There was a really good thread on LS1Tech a while back about this same issue, but those guys were using 2 steps. Similar theory, though.