Zach-R

iTrader: (3)

Alright guys I'm working on installing a zex wet kit but before I get to far ahead of myself here's some info.

98 Se 5spd
Full 00vi swap tuned with vafc and aem wideband
power rod removed
I/H/E etc
Zex wet kit with nmu
Ngk bkr6e 1 step colder plugs
93 octane
Stock fuel pump temporarily
Megan racing adjustable fpr

I'm starting out on a 55 shot and hopefully work up to a 100 shot safely. My biggest concern is the vafc I understand it advances timing indirectly when fuel is pulled. With the 290 dek injectors I had to pull a bit of fuel. Now I guess my questions are

1) How much does the vafc effect timing related to % of corrections. My highest correction currently is 8% and that's for a 13:1 ratio afr. I will be retuning for a safer afr most likely 12.3-12.5:1.

2) This is the big one! Can I safely use the adjustable fuel pressure regulator to lower fuel pressure and adding fuel through vafc in an attempt to retard the timing? The zex kit says 38 psi minimum for fuel pressure.

3) Should I just pull the knock sensor, retarding timing 8 degrees and not worry about it?

4) Any other information or advice is welcomed. Thanks .org!

Zach-R

iTrader: (3)

Guess I'm on my own here. I'll report my experience anyways, might help a nitrous newbie like myself somewhere down the road.

Spoon_

iTrader: (1)

Please do.

Zach-R

iTrader: (3)

Works kept me busy but should have time this weekend. Basically I'm going turn fuel pressure down a few psi and attempt to compensate with the vafc until my corrections are atleast 0 or atleast positive on the corrections.

I have no idea how much 1 psi will need to be corrected. The zex kit requires 38 psi and the 4th gen wot psi is 43. Just have to see how it goes.

Zach-R

iTrader: (3)

Well it's been setback after setback here. Somehow I closed my hood and my grill broke, wired up the zex nitrous management unit and Harlan window switch now my tachometer no longer works but the tach on the vafc works fine, lost the bulkhead fitting for my nitrous nozzle and had to order a new one.

This coming weekend was slow motion motosrports dyno day but I doubt I'll be able to make it.

Zach-R

iTrader: (3)

Car was T boned and totaled today. Sorry I have nothing else to report. Probably be getting out of the maxima game still to be decided.

VQ'ed

iTrader: (2)

I'm curious on the answer for the 8 degrees pull when the knock sensor is unplugged. Can we get away that easily?

MoncefA33

iTrader: (6)

Depends on the car, whether its 95-01 or 02-03.

There's a thread out there somewhere that shows the timing curve with KS unplugged on a 4th gen Maxima, should be similar to that of an 00-01.

02-03 Maximas usually see around 8 degrees absolute at peak torque with KS unplugged, and eventually creeps up to 20 degrees at 5,000 RPM and holds that to redline.

I do not recommend doing this as a way to increase the safety of a nitrous system or turbo setup, mainly because too low of timing will knock the motor as well due to inflated EGTs. (A lot of boosted VQs will be okay around 10-12 degrees at peak TQ and 18 or so at peak HP to redline, nitrous cars like more timing than that so I would retain the factory KS up to 100 shot, tune fuel with jets and 1 step colder plugs, and start to play with timing over that).

VQ'ed

iTrader: (2)

Thanks for the clear answer, Moncef