1KZ correction resistors

[2MEKE]

Feeling a tad bored a few weekends ago I decided to have a go at getting my old Surf moving a bit quicker.
Did a fair bit if reading re the correction resistor mod on the Aussie forum and these are my experiences....

The vehicle is a '93 KZN130 auto.
No mods other than a 2.5" straight thru exhaust and blocked off EGR.
boosting to 0.8bar
uses 13.1l/100km consistently
EGT probe in the collector pre-turbo
Original resistor values
VRT = .571kΩ
VRP = .345kΩ

I first made and installed a ball & spring type boost controller set to 1.1bar, disconnected the std resistors then wired a couple of potentiometers into the ECU and started playing with the levels.

Highest power output was reached with
VRT @ 1.85kΩ
VRP @ .650ishkΩ
It came on boost very quickly...full boost by 1600rpm
EGT didn't get over 650c
But she was drinking fuel at 15.4l/100km and I wasn't giving it a hard time

After a fair bit of playing with both values I've settled on (for now)
VRT @ 1.85kΩ
VRP @ .345kΩ
Boost doesn't come on quite as fast but probably still twice as quick as pre modification. EGT stays under 600c and fuel usage is down to 10.7l/100km.

I think there's still a little bit more to be had out of the electronic pump but not without inter-cooling and maybe a new dump pipe/exhaust.
Maybe I'll get bored one weekend soon...

[churchill]

Nice mod!

[2MEKE]

Bang for buck it's pretty good....total cost $9.10 + a few bits already in the shed.

Gets along as quick as the old mans inter-cooled 185 series now....almost

[Smurf]

Wicked results.
I have read that this is also a common mod overseas for the 2L-TE.
Times like this I wish I was a little more electronically savvy, as I would really like to try this mod out myself.

[charlies paj]

Any chance of a bit more information on the process to do this mod ? thanks

[2MEKE]

Electronically savvy?...not me. I only know the basic stuff.
Plenty of reading did the trick

This is the thread I read http://toyotasurf.asn.au/forum/viewtopic.php?t=29886

The boost controller is little more than a few brass fittings



How it works...



For the pump I started by unplugging the resistors and measuring their resistance so i had a reference point to work from then I made up the contraption below...a couple of 1kΩ potentiometers, a 1kΩ resistor and a switch.

VRP (fuel) runs straight through the pot as it wasn't going to need to go over 1kΩ.
For the VRT (timing) I wired it through the switch and added a 1kΩ resistor inline on the high setting to give a greater range.
Turned out this wasn't needed.

The high tech tuner was connected to the wires that came off the injection pump, set to the original values I'd measured then I went for a short drive to confirm the truck still drove the same.
I did, so I started playing with the settings while keeping an eye on what boost, EGT, water temp and the fuel gauge did.
All the tuning was seat-of-the-pant and knowing how the vehicle performed on certain sections of road I drive every day.
On one occasion I had returned the tuner to the factory settings prior to beginning a long 60km/h climb.
I was sitting at 60 heading up the hill then changed to 1.8kΩ VRT and .6kΩ VRP without moving the accelerator. My speed increased to a tad over 80km/h. Egt also decreased.

Only thing I'd do different is buy lineal pots rather than logarithmic but the day I went to Jaycar that was all the had.
Logs work fine but are a bit harder to adjust accurately.

HTH

[Checkerhead]

Bloody good work mate.
Plenty of people playing with mechanical pumps, nice to see some tech on the electric ones. Especially as mechanical ones are getting less common.

[bob_or_jim]

Hi, awesome work mate. I have done a similar thing before but didn't have ext temp gauge to verify results. Reading your results it almost looks like you need a cruise setting and a power setting. Be good to have the power but then fuel economy while cruising. Anyway keep up the good work mate!!!!

[mike]

wicked, so doing this!

Have you done the torque converter lockup mod? This will be awesome with it

[2MEKE]

Bloody good work mate.
Plenty of people playing with mechanical pumps, nice to see some tech on the electric ones. Especially as mechanical ones are getting less common.

I've got the bit to do a manual pump...just need some spare $$ to get it built and buy a new turbo. I still think a manual pump, heaps of boost and W2A IC or water injection is the way to go.
This was cheap, easy and able to be done whilst still using the truck as a daily drive.

Reading your results it almost looks like you need a cruise setting and a power setting. Be good to have the power but then fuel economy while cruising.

IMO the little bit more power is not worth the extra fuel

Have you done the torque converter lockup mod?

Not yet. I have tweaked the trans cable and am contemplating dropping the pan to turn up the line pressure tho.

[bob_or_jim]

Have you done the torque converter lockup mod?

Not yet. I have tweaked the trans cable and am contemplating dropping the pan to turn up the line pressure tho.[/quote]

Couple of questions for you, increase in line pressure........how does that make the trans behave. I hoping your going to say it shift a bit crisper (is that a word?) and not slip under load. Also is there an easy way to gain access to adjust it or does it involve shim washers etc.

Cheers

[2MEKE]

increase in line pressure........how does that make the trans behave. I hoping your going to say it shift a bit crisper (is that a word?) and not slip under load.

Not quite snapping between gears but heaps better. Crisper seems like the right word for it.

Also is there an easy way to gain access to adjust it or does it involve shim washers etc.

I haven't increased the primary yet as the pan has to come off. Only tweaked it via the throttle.