**EDIT** it doesn't do anything. Ignore the # if you have a car.

**MOD EDIT** As was mentioned multiple times in the past, present, and future most likely


I just started reading about it. Apparently, it delays PE mode under the rpm you set it at.

Stock was 5500 rpm.

So, I set it at 1200 rpm. I can definitely feel PE kick in sooner and faster. Thus, my car feels faster, especially in the 3000-5000 rpm range.

Now, I can probably tune PE more accurately at all rpms.

Anyone else mess with this?

If I'm understanding it correctly, before I changed the value, if I punched the gas at 2k rpms in first, it would blend between stoich (14.63 a/f) and PE at that rpm (about 12.4 commanded right now) until it would end up at the PE commanded A/F.

So, I was technically running lean when I punched the gas under 5500 rpms for a little bit??

So, now if I tune PE at 2k-4k, should the values be leaner (lower PE multiplier) for those ranges compared with 4k plus?

 

actually, although you see a parameter preset in that field, you do not have a PE delay. I don't believe any GM cars had a PE delay (mentioned somwehere way long ago, it was meant for trucks while towing. So no, you did not feel anything extra. Ever seen a stock dyno run? If a car without any prior tuning can make 12.5-13.0 A/F on a dyno at WOT, that would be a good indicator if you have any "lean" bias there, at least not due to any PE delay. If anything, the only reason why you may run lean at WOT, is if you've enhanced airflow through modifications, and not adjusted the MAF, the WOT VE areas, or PE multipliers to achieve your desired ratio. From stock configuration, the PE multipliers are far off from producing commanded A/F.

 

I read it somewhere too about cars "not having PE delay" yet, there it is, with the number 5500 put into it.

And in the HP tuners "help section" it reads: Mode Delay RPM: PE mode is delayed if RPM is below this value.

I haven't logged since I changed the value. But, on my previous logs, my LTFTs wouldn't hit zero until about 4400 rpms when I floored it from 1200 rpm in 1st gear.

I don't have a wideband, so I don't know if it was lean before at 2k rpm or whatever.... So I'm looking for some insight from someone who's changed the value and used a wideband to compare before/after.

 

i've had some experience...



It makes no difference....

 

I'm not saying that you don't know what you're talking about, you obviously have some experience in tuning......

But, unless I'm understanding what he wrote incorrectly, the HP tuners owner disagrees....

"PE delay is used to delay the onset of PE mode. We don't actually show the delay in the editor because setting the delay RPM to 0 eliminates the delay."

http://www.hptuners.com/forum/showthread.php?t=5634


Again, if I'm understanding it correctly, this doesn't keep you from entering PE under that RPM, it just "DELAYS" how long it takes after you meet the criteria (TPS %, RPM, MAP, etc.) to go into PE mode.

What I think I felt today, was that when I punched the gas at 3k or so in 1st gear, it had better throttle response.

I'm just trying to figure out if it was just in my head.

 

And I have done wideband logging/testing on cars stock, modified, highly modified, broken, some with PE "delay" some not, and after all that, i'm shooting down he idea that it causes leaner A/F ratios by virtue that it is "delaying" PE fueling. I thought I was addressing your initial question quite adequately

As for your thoughts on throttle response. I have reflashed an exact tune in someone's car that had ZERO changes from what I pulled originally ( ), and he was so impressed with the throttle response. The mind can be a powerful thing, in my own experience, and through many other vehicles, never has modifying this parameter led to any noticeable or quantifiable measure of performance. But if it bothers you, set it to zero. Doesn't hurt a fly.

 

From what I have seen the commanded A/F is slower to transition to PE values when the delay is set to 5500. I changed my value from 5500 because before my commanded A/F was just barely getting to the PE value at low RPMs, after changing it to 1000 my commanded A/F was right where it needed to be without what felt like delay. Make any sense?

 

all cars have the PE delay set at 0, regardless of the PE delay RPM. We didn't add the actual delay table (for truck owners) because there's no real point, no-one wants to shorten the PE delay they just want it gone, which setting the PE Delay RPM to zero achieves.

 

 

Well, I went back and looked at some logs I did before changing th delay rpm number.

Regardless of RPM, when my throttle is 100%, my STFT and LTFTs are all zero, and commanded A/F is based on my PE number.

So, it's all in my head.

 

Is there anything that momentarily enrichens the fuel like in the old days of accelerator pumps?

 

i have never messed with the delay table and i get what i am commanding as soon as i stomp on it, regardless of the rpm i am at. So IMO PE Delay table has no effect on anything.

And yeah I log wideband all the time, as a matter of fact always, I got one of those zeitronix LCD wideband kits so its always right in front of me.

 

One of the tuning guides, can't remember which one made mention of this delay field. Can't remember the exact wording but something along the lines of "reducing this number to launch or stall RPM is sometimes a fix for tip in KR problems". I assume based on what I've read here that would be incorrect?

Found the post in the stickies; http://www.transamws6.net/HPTuners/ls1tuninginfo.doc

Read PE tuning section.