Search found 51 matches

by jaf
27 Apr 2014, 20:30
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

As promised, this is pretty much the final state of tune for my X-Trail. After flashing over 150 times trying out every permutation possible, it has boiled down to a relatively simple tuning of cam advance, AFR and ign timing. The constraints have always been: 1. It must run on 91 octane. 2. It is m...
by jaf
17 Apr 2014, 20:15
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

A bit of a diversion from the QR25 but all useful stuff.... Here is an example of cam timing for the 350GT utilizing the later scheme adopted by Nissan and most others: 1. The "hump" lowers compression and therefore pumping losses. It also introduces a degree of EGR action. If it coincides...
by jaf
15 Apr 2014, 18:59
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

Hi Tom, Not sure what conversion formula you are using on your maps? Does your logging agree more or less with the expected advance? I assume you have around 32 degrees absolute max advance so 35 degrees really means max? For a quick fix on the original ROM, I would shift everything left one column ...
by jaf
12 Apr 2014, 20:11
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

6E11 is the main CAM map. Hard to say whether the calculation for units should be the same as a 40 degree VVT model or not. A log would show the correct way. The uneven spacing is taken care of in the spreadsheet if you look carefully. The first image I posted is skewed since I did not have the axis...
by jaf
12 Apr 2014, 11:46
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

Thanks for that info. Any idea if the compression ratio is 10:1 or 9.5:1? What you have said makes more sense of the ROM. The AFR table has been comparatively leaned out to stop the cat disintegrating again - that also helps performance but it looks like they pull a lot of cam timing under load so y...
by jaf
11 Apr 2014, 21:59
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

Hi fenugrec, Can you match up some rpm and load axis to the timing, AFR and Cam maps on your ROM? I guessed that the middle ign timing map on the X-Trail is the Low Det map as in the Sentra ROM and this is holding up as correct so far. I have increased the high load timing to be more like the Sentra...
by jaf
05 Apr 2014, 21:28
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

Here's a quick look into your ROM. Tuning is vastly different from the X-Trail but not necessarily for the better. Many maps are identical (as also found in the 350GT ROM) I am tempted to flash this into my car to see what happens.......what could possibly go wrong? Can you give a bit more detail ab...
by jaf
05 Apr 2014, 19:42
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

Congrats!! Another first.
I will take a long hard look at your ROM and let you know what is of interest.
70 mins is about how long it takes for me so there is a bit more speed to be had.
Seems there is more interest in the QR25DE than the 350GT - must be related to the tuning potential ;)
by jaf
08 Mar 2014, 19:36
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

Ha Ha! Opposite problem here - best to wait till winter to do garage stuff. It wasn't hard to find 2 other X-Trails in the work carpark when I was working with 350 other people. I had to set their timing and idle for the privilege of dumping their ROMs though (and diagnose a blown head gasket in the...
by jaf
07 Mar 2014, 20:17
Forum: ECU Tuning
Topic: QR25DE Tuning
Replies: 104
Views: 47049

Re: QR25DE Tuning

Hi fenugrec, The process to figure out the checksum addresses was simple: download 3 ROMs from the same model car but with slight variations in code. Look for the bytes that always change and there is your checksum. The Nissan checksum algorithm has been around for quite some time unchanged so that ...