Thread: Tuning for optimal mpg with DHP

Take a peek at the PE Enable Cylinder Mass Air vs RPM table in thingy suite or tiny tuner. GM left this zeroed out for all 97-03 w-bodies, so as a result most tuners will use TP% to decide when to enter PE. This either results in worse fuel economy from entering PE too early, or knock from entering PE too late. Using cylinder air mass is a better solution since it relates to engine load. I used PE Enable TPS of 15-30% coupled with the cylinder air mass enable (both conditions must be met for PE to be triggered, so you want to set the TP% low). Result was a vastly improved daily driving experience. Give it a try some time. Table I used for cylinder mass enable follows.

520
520
520
420
480
480
440
460
460
400
85
0
0
0
0
0

This should be a good start, basically what you're doing is using engine load to determine when to enter PE. You can raise the cylinder mass numbers to enter PE at a higher load, or lower to enter at lower load. If you want to tune the numbers further, you want to enter PE as late as possible while still maintaining no knock in order to maximize fuel economy.

I don't have DHP anymore I have HP tuners now but I'm at the PE tps vs rpm if that's what you mean? And my numbers are 40, 40 etc etc etc not 3 digits unless yours is 58.0

that's PE enable by throttle position. There's another table that allows you to enable to cylinder air mass (basically engine load) instead, but I don't think HPT gives you access to it.

Yea can you use tiny tuner? If you know

With HPT? Sort of... I believe you can read in a .bin once, then it gets converted to a .hpt. So you could start with a stock .bin for your vehicle, modify it with TinyTuner, than load it with HPT. But you can't (easily) go the other direction (from hpt to bin)

AFAIK anyways, I've never had HPT so I'm just going on what I've read.

Not sure, did you follow the instructions in the Read Me First file to get the database pulled in?

Eddie is the expert since he wrote this stuff. Perhaps you're using an OSID that's not in the database? But if that were the case you shouldn't see any tables listed. Could be the access database is malformed, I don't know that the public release has ever went through much testing. Try loading a different OSID bin out of curiosity to see if it's specific to yours.

Originally Posted by Scottydoggs

it still refused to take my bin, tried another one, it took, so i then went to my bin and it saved it, put your numbers in and then took 10% out of the tps on each line to 2800. that sound ok you you?

Sounds reasonable, flash it and do a scan while trying it out. If you load the scan into table modifier, you can see what the calculated cylinder air mass was if you need to do any tweaking of the PE start points.

One more table to take a look at: PE A/F vs TPS. I ended up richening this up quite a bit over stock since you're hitting PE at lower throttle now. Table I used below.

1
1
1
1
1
0.7197266
0.4501953
0.2597656
0.09960938
0.009765625
0

99% chance you are not using the "use database when available" function, or you are trying to use an unsupported OSID, which in that case you need to add it to the database.

I thought I saw a dhp guide on tuning for optimum fuel economy, but after looking through Bill's drop box, I have come up empty handed. maybe I need to do some more searches.

+1 for more info on tuning for MPG. Getting a commuter GTP for my wife and she is more concerned with saving gas than raw HP. I have a DHP but as I haven't gotten my car assembled yet, I haven't played with it much yet.