1kz Resistor Mod and Boost cut defeat.

[bob_or_jim]

I have been scrolling through numerous blogs/threads/forums looking at what people have done as far as modding there fuel pump resistors etc.

It seems that everybody that has done this is happy with the results. So I thought Ide have a go but also play with the boost cut

Reason I have chosen to do this is to see what I can see what the elec pump can do. I know people will say that just do the mech pump mod and you won’t look back but until funds become available this is my next best option.

Anyway is seems that the two resistors on the side of the pump have a reasonable impact on the performance of the little 1kz. 1 resistor controls the fuel quantity and the other does the timing with an effect on the fuel quantity.

According to the Toyota pump manual the factory resistors available give you 6deg of adjustment in the timing, but this is not limited to 6deg as it has been proven that raising the resistance to higher than what’s available from factory gives even more scope for adjustment. As for the fuelling there is between 0cc and 3.72cc's of adjustment per 200rpm when the motor is running at 1000rpm.
That means you would burn 18.6cc's more per min @1000 rpm! Probably doesn’t sound like much but with my Surf running at 2200 Rpm @100kph it equates to 2.455LPH on top of what I would normally use. (Obviously we would be speeding trying that out).

All that aside my point is we can play with this pump and get a little more out of it for a very small price (providing I don’t blow it up!!)

My plan is to get 2 pots rated to .5w and 2kohm of resistance from Jay Car P# RP3508 and 2 switches P#ST0335. I’ll put these inline with my current resistors and have a play. With the switches ill wire it up so I can switch between standard and modified for a real time comparison. (price approx $15)

My next step after that is to disable my boost cut as per this article http://www.autospeed.com/cms/article.html?&A=109135

Then use a pressure switch (maybe the MAP sensor before the boost cut?) to switch in a larger resistor to bump fuel up while boosting over standard levels.

This won’t be an overnight project but I’ll get the pots and switches this week and start wiring it up into a remote box so I can adjust from the cabin.

If people have any ideas or corrections to my ideas then feel free to provide input. Still learning about this but there is plenty of info to sift through.

Cheers

[slidenyo]

add a pyro gauge and you will see some real numbers starting to form also,
kz's I have come into contact with have been pretty strong to a point then have had head gasket issues, really do wonder whether an arp rod kit for the top end would be a good option to clamp it down.
I'd suggest that running with two lots of extra settings would be a good idea and taking numbers pyro boost rpm etc down over a consistent run as you switch each one so you can see the real effects of your changes.
Seat of the pants tuning is always good but can be expensive if something lets go

[bob_or_jim]

Yeah agreed. I have a thermocouple to add to the exhaust for tuning etc so should be able to help.

Im only really after the power I had before the 33's were fitted which is easy to test as my Prado could only just keep up with the Surf prior to fitting and now it pulls away. So if I can get it to keep up with it ill be stoked. If not the lower EGT's will still make me happy.