Tuning the 3500Z

[Superdave]

I figured i'd start a thread here to maybe get some input. Moonwell and I are working on getting this thing running right. Currently i'm running a chip tuned for a cammed 3400, i've adjusted the idle to 1125-1200 across the board.. also changed the fan1 enable/disable temps to work with my 180F thermostat. Plus some other minor changes so it would run my #32 injectors...

A full list of the mods can be seen here: http://www.v6z24.com/registry/whitelightning2/

my thread on V6Z24.com: http://www.v6z24.com/jbodyforum/my-0...ve-t90913.html

and attached is the first of many datalogs to come...

[Superdave]

I think the weird o2 values are being caused by the cam.. the o2 is in the crossover pipe so it's only seeing the front 3 cyls.. I'm planning on welding in a 2nd bung after the merge and installing another heated o2 this weekend.

[sil]

you should get seperate shorter logs
idle
2000 rpm in neutral
light accel (no PE)
decel
WOT from stop

i like the timing at WOT lol goes up to 33.x, im going to have raise mine alot me thinks

and i thought the pcm goes into open loop and doesnt bounce the o2 at WOT
seems like yours is swinging in WOT

pretty high idle, doubt its even using the idle routine in the ecm ?
maybe its just me but id try to at least get it to idle at 900

you can tweak certain areas to get some map back like less iac for example
play with idle timing

what are you using to get logs?
what ecm are you using? mask?

[Superdave]

you should get seperate shorter logs
idle
2000 rpm in neutral
light accel (no PE)
decel
WOT from stop

i like the timing at WOT lol goes up to 33.x, im going to have raise mine alot me thinks

and i thought the pcm goes into open loop and doesnt bounce the o2 at WOT
seems like yours is swinging in WOT

pretty high idle, doubt its even using the idle routine in the ecm ?
maybe its just me but id try to at least get it to idle at 900

you can tweak certain areas to get some map back like less iac for example
play with idle timing

what are you using to get logs?
what ecm are you using? mask?

Yah, the heater isn't hooked up on the o2.. i need to put a relay on it so it's not pulling off the ECM's power (was blowing the fuse). That's probably why the values swing around alot.

Freescan to get the logs, '7730 ECM/$A1

We adjusted the VE a little in the upper RPM's and it's doing better...

WOT run or 2

http://www.3500z.com/3500/Misc/WOT%20Runs.csv

Some Highway cruzing..

http://www.3500z.com/3500/Misc/highway%20drive%20with%20new%20V%20E.csv

ther eis no way this thing could idle at 900.. i'm guessing 1200 or so is where i'll end up setting it. When i come to a stop at a light i gotta keep the corner of my foot on the gas a little so i have enough vacuum to use the brakes.

[IsaacHayes]

Time for a bigger vacuum tank or a vacuum pump!!! Make sure the check valves are working in it too.

[torq455]

seems rich at idle. or commanded anyway. or was it cold during that log?

[sil]

its prolly not that rich, if he pulled his plugs i bet there somewhat ok
the duration of the cam lets unburnt air throught tot he o2 and the ecu thinks its lean so it tries to richen it up
then we think hey its rich and we try to lean it up
bad

so.. you need a wide band or check your plugs, theres a trick you can do
raise idle zerfru low and high up about 50 mV
and open your throttle blade up alot
reset ecu...

that will get it to idle lower and the ecu will not be so "im lean" lets make it richer, human error thinking its rich lets lean it up

[Superdave]

ran it on a dyno the other day to get a baseline.. was pretty dissapointed but i guess i'll have to spend more time with it now...

http://www.3500z.com/3500/Misc/1stdyno.gif

here is a vid of that run...

http://media.putfile.com/3500Z-Dyno

the AFR on the graph may be off, the WB was clamped to my exhaust tip and the tips aren't welded all the way around so it's possible that it was pulling air along with it giving a false lean.

I made 3 runs, 1st run was reading rich, low 12's AFR, 2nd one the duct tape they tried sealing the exhaust tip with caught fire and that's when the AFR's went way up...

I'm planning a return trip to see if i can do a little better, I'm working on a few different .bin's to try. It's possible that the 3.4 DOHC timing table i'm using is too much advance.

this thing should be closer to 280/290 WHP..


WBo2 is coming soon as well, now if i could find a good deal on an Ostrich emulator i'd be in good shape


On a side note, i wonder how much power having a F'd up front end alignment is costing me... The front wheels are toe'd in and the camber is way f'd altho it still drives semi straight. Tires squeel lightly going straight and worse around turns.. haha

[Joseph Upson]

Why did you choose the 3.4 DOHC spark table over the Turbo Grand Prix table? I haven't been able to compare them but I would expect the flow characteristics to be much closer to those of the engine with similar style cylinder heads although the compression on the TGP 3.1 is lower. The TGP table is weak to me but I'm used to looking at the Fiero iron head table which is very, very different and much more aggressive.

The timing is one of the tuning concerns I have, given the compression level of the 3.9 and having purchased the Moates APU-1 I decided once the engine is installed and running I would look for a baseline by increasing the timing at the grid the engine idles in until I get a knock then shut the engine off and back the timing off at that point by about 3 or 4 degrees and increase the entire table by the final result before moving to other random areas for more testing.

I also have a Zeitronix unit with WBO2 because for once I want to make a serious effort at proper tuning. The reason I'm concerned about the timing is that if it is not first optimized you can actually tune the engine to a weak table.

I imagine after I tune the engine and head for the dyno, I could increase timing at 2 deg intervals between runs to look for improvement since there is a point at which you will not see power increase and at the same time not get any detonation. The last I checked there was a dyno at home that charged $60 for three pulls, 6 should be enough if I do a good job of tuning before hooking it up.

Your numbers at the wheels are higher than the stock numbers at the crank so that's a pretty good accomplishment considering you are kind of guessing at the tune. I could have told you that tape would probably catch on fire and maybe you need to deal with a different group of guys for having taken such a risk and you are right about the leak areas in the exhaust probably pulling in fresh air and screwing up the AFR reading.

You should add a turbo, I bet that'll take care of the disappointment

[Superdave]

Well...

Here is the 3.1 spark table..



And the 3.4 DOHC




and then the turbo 3.1...





and what i'm currently running...

[Superdave]

welp, the stock fuel pump took a crap so after replacing it with a stock pump for a 350 TPI the BLM's dropped as low as 91!


got a new (very long) datalog today with most of the stock 3400LA1 spark table. I'm seeing some things that don't make sence.. I'm still running the stock 3400 o2 sensor (NB) but it's showing .7 and .8, even up to 1.012V while it's in PE mode. the computer is commanding a 12.3 AFR. I'm no expert but that just dosen't look right

Getting a little more KR than i'd like but that's an easy fix, the rich/lean is what i'm worried about...

I'm waiting on 1 final piece for my wideband, whenever it gets here i'll hook it up and get some more accurate logs.

[ForcedFirebird]

Have you tried moving the NBo2 to the collector?

As far as a bung, I just go to a fastener store and buy a 18mmx1.5 nut, cut it in half the long way, then drill/weld into the exhaust. They cost me $3 for four.

EDIT: I guess that is a long log, almost 6.5Mb

[torq455]

sounds like more tuning is needed. it's almost like at certian points you run lean, then rich.