NVK4 isn't half bad for DD.

[cleatus12r]

Here's a little background:

Almost 2 years ago I purchased Sniper Delta Force tuning software and spent a ton of money on numerous "templates" (their name for "definition files"). I currently have VRAA6, VRAA7, and VNAA8 for DPC-422 boxes. I don't need them, but I initially ended up with VNAA8/NVK4 from my supplier.

The first thing I found out was the NVK4 didn't work. Great. Well, that's not what I wanted anyway so I bought the one for my present box code, VRAA7/PMT2. It worked so I just used it for a while until I learned of the almighty PMT1. So I paid another ridiculous amount of money for VRAA6.

For the last 2 years, I've pretty much worked exclusively with PMT1 for the 99.5-01 automatics....much the same as most custom tuners do.

I finally got the desire to work with NVK4 again since I have it, I paid money for it, and I was curious as to how it stacks up against the dozens of other automatic PCM codes I have driven.

Well, big surprise again, but it still didn't work. The wait to start light came on, the fuel pump ran, the WTS light went out...OK....Crank....no start. No ICP desired during crank....well the map for ICP says that it should have some.

It just so happens that I bought a PCM from a guy on PSN the other day (unmolested NVK4) so I snagged the binary off of it, reordered it, and put it in the VNAA8 definition along with the original NVK4 binary that Sniper sent me. Well, the ICP desired table (map) showed nice, valid numbers for the non-starting binary and the known-good binary straight off of the PCM showed way wacked-out ICP values. Hmmmmm. Bad binary AND a junk definition file. Great. The SOI maps (high and low elevation) are also screwed up in the definition (but the binary seems ok there).

I started tuning the fuel/SOI/APP stuff in the VKAE3 definition in Minotaur (since the addressing correlates between NVK4 and VKAE3 in the important maps and the scaling of the graphs is actually useful).

NVK4 works pretty good for daily driving. The only real complaint I have about driving it empty (just daily driving or sportin' around) is the early 3-4 upshift....but that's one of my major complaints for ANY stock 3-4 upshift speed. Easily fixed that. It's just too bad that it doesn't like my horse trailer too much...I certainly wouldn't use it for a truck that tows anything. Besides, I like my torque converter clutch to stay applied when I hit the brakes. It does keep the TCC applied on a 4-3 downshift too which is REALLY nice (the big thing I hated about PMT2 vs. PMT1).

All in all, I don't think I'd be too overly upset with running NVK4 in anything since it does work pretty dang good out of the box. I've probably put 35 miles on it so far and I have a feeling that my wife will love it. She's not a big fan of PMT1 (or the way I like my PMT1 to feel) so I had to molest the heck out of the PMT1 to make her a tune she liked to drive.

It's just unfortunate that I can't mix PMT1 and NVK4 on one chip.

[cleatus12r]

Before anyone goes off about my not-so-happy experience with Sniper, I must say that Chris Stajdel is a helluva guy. He's always been very courteous and punctual with upgrades or sending of different definitions. He actually sent me another VNAA8 template (but unfortunately it's also not right) today. Not that it matters. I like to use Minotaur anyhow because of the graph scaling.

Not knocking them at all....they just have a bigger fish to fry with their gasser software.

[907DAVE]

Interesting.

How many differences is there really between all the different PCM's.

I am going to guess that the largest difference would be in the shift strategies, but how about the engine stuff?

[cleatus12r]

Engine stuff....

Very little.
You're right about transmission shifting and torque converter clutch strategies.

There are those that really suck and make no sense, there are others that work OK but you can't fix them to be perfect, and then there are the ones that really work well.

The list of automatic PCMs I have driven:
MRT2 (super suck)
NVK2 (sucks)
NVK4 (not bad)
MNM0 (NVK2 wanna-be)
MNM1 (not bad)
PMT1 (awesome)
PMT2 (not bad)
PMT3 (not bad either but didn't notice a difference from PMT2)
VDH2 (suck)
VDH5 (super suck)
TDE0 (ok)
TDE1 (better)
NAW4 (absolute crap)
LKM6 (TDE1 wanna be)
YBT1 (garbage)
XLE4 (sucks)
XLE8 (not as bad as 4 but still sucks)

[cleatus12r]

For the most part, the automatic PCM calibrations are tantamount to Rod Stewart and.....uh.......


Rod Stewart.


The fueling and SOI changes are usually pretty minimal. The biggest changes to those maps are the normalizers.

[907DAVE]

Rod Stuart eh....