G-Zone For M35S

[richzx]

I was thinking of running to the reverse switch so that everytime it went into reverse it would reconnect the circuit but I guess thebrake is even better again. Is there any issue with the constant on/off of the brake pedal connecting the circuit?

[slippylotion]

Reverse switch is an awesome idea.

[MOUTH]

I stalled it up and launched it a few times and couldnt notice any difference, neither could my mate. We both noticed a heap more when I fitted a plenum spacer to mine.

I might try it on mine one day and double check but after the feel of his I'm in no hurry.

When I did this mod, I can easily tell the difference with the stall test (my car is stock), with my switch off you stall it up, it slowly revs, it only gets to a certain rev and the wheels slowly spin, with the switch on it revs up a lot quicker and spins the wheels ALOT more wit higher revs. I dont stall it up to that extent at all really, but out of corners in the hills it is very noticeable also.

[MOUTH]

Yeah off of the footbrake is more what I was thinking about. Basically the wire needs to be "uncut" and the brake pedal pressed to reset the CEL/limp mode?

I just have a switch in the top of my glove box, once every 2 or so full tanks I get the check engine light on. Open the glove box, flick the switch, and a couple of brake applications and the light goes off in under a minute.

[scotty nm35]

Wrong wire cut Paul?

[slippylotion]

I cut the pink with purple trace in the centre of the ECU plug. Is this the correct wire?

[scotty nm35]

Pink with a blue trace? Pin 55 anyway I seem to remember. Yep, in the middle of the plug.

[slippylotion]

Yeah that's the one.

[zei20l]

there is another pink one that i cut. i was one of the ignition lines. 5 cylinders sounds awesome at idle

[Commsman]

Anyone feel free to complete this sentence:

The best solution for someone that is happy doing under 171kmh, with a front mount, dump and exhaust is.....

Here's what I have learnt from lots of reading & a fair bit of experimenting. This is info that I wish was available specifically for our M35's when I started playing around. But really there's nothing new here.

One day I might write up a budget build thread for those who, like me, want more power without sacrificing fuel economy & without spending a fortune.

To answer your question:

1) A good wideband meter; preferably one that has a programmable narrowband output. I like the one from http://14point7.com/Products.php. You might have seen that I remote mounted the display on a length of ribbon cable, but you could just stick it on your steering column till you get the AFRs right, before tucking it away under the dash. Or buy their 52mm gauge for an extra $50.

2) A method of adjusting AFR's. I've used a Jaycar kit (voltage modifier) but the above website also has a UAFC with 3 individual maps which can be switched on the fly. It looks really good for the money.

Once you have the above in & working (~$400) you can tune the car on road (or dyno of course) for both power & economy. That should form the basis of tuning future mods up to whatever power level you want to go, given the right performance hardware. (Note to self - expect flame war, lol)

If you want to go further:

3) New & larger intake (suction pipe) will make a vast difference to the breathing of the engine. You can tune the AFR's perfectly well using points 1 & 2, but you will find that you will be running lean at the top end. In fact some guys will say they are running lean without a suction pipe. I should mention that most intakes will cause the AFM voltage to max out, hence the reason that guys at that stage start looking at E-manage or F-con etc., so they can use a MAP sensor. It doesn't have to be that way...

4) A fuel pressure regulator (rising rate) increases the amount of fuel that is squirted thru the injectors at any given duty cycle. Straight away I had to decrease my AFM adjustments because it was running too rich. Now my injector duty cycle doesn't go above 90% (had reached 100% previously) plus I can run any AFR's I want, at any load point, including at the very top. So fuel delivery (still stock fuel pump) is not an issue with standard turbo (now at ~16.5psi).

5) Boost control. The factory boost control is pretty good but you can get a bit more out of it by tinkering a bit.

Obviously if I wanted to go larger turbo with much higher boost I know I would need larger injectors. But even then I don't believe I will need to change my method of engine management (AFM voltage modifier + standard ECU) if I am sensible with the size of the injectors.

OK, so points 3 & 4 will cost about $200 if you DIY & boost control costs say $100 & up. Best thing is there is absolutely no trade off. My power is way up, driveabilitiy is factory smooth, throttle response is outstanding and economy is better.

Haha, I just looked at how much I typed and maybe I should have started that new thread after all . I'll shut up now, but I hope this gives you something to think about.

Cheers, Leon.

PS. There are plenty of benefits with choosing a higher end solution (eg E-manage / F-con), like cam timing & probably heaps more that I don't know about. So what I wrote above doesn't mean I think those solutions have no merit. It is just my interpretation of the question. Also, my slightly unique situation (no tuner or dyno near by), & modding ethos, means most of these other solutions were not given serious consideration. Whew, possible flame war averted, lol.

Edited November 6, 2011 by Commsman

[impul535w]

Leon.

Have you had your car on the rollers? What numbers were you pulling?

Mike.

Edited November 6, 2011 by impul535w

[Commsman]

Leon.

Have you had your car on the rollers? What numbers were you pulling?

Mike.

Not yet Mike as there isn't any suitable dyno around here. I will probably go to the Gold Coast before Christmas, possibly to Chip Torque but open to recommendations from anyone from around there.

I'm not really a numbers guy as I'm more about what it's like to drive, but am curious nonetheless.

[joshm35]

there is another pink one that i cut. i was one of the ignition lines. 5 cylinders sounds awesome at idle

Now it is a volvo lol

[Commsman]

I'm not sure where this should be posted, but there's plenty of talk about the brake wire mod in this thread, so it's going here.

Today I had an opportunity to log a couple of runs, without the brake wire cut mod & with it. You can clearly see the ~30% restriction in the first pic, although there is weird burst to 100% for a fraction of a second - maybe it took an instant for the ECU to realise I had my foot on the brake when I floored it?

Anyway, blue line is throttle voltage, green line is AFM voltage & yellow is boost. You can see that boost rises quicker when the mod is active, & acceleration is noticably quicker as well.

I just thought this might be interesting to some people.

Cheers, Leon.

[slippylotion]

Nice work there Leon. For beginners like myself, is the brake wire +12v? Just trying to work out how to wire in a relay to the reverse switch on the gear shift so it resets everytime I drive the car and don't have to explain the need to reset a switch to the missus.

Any help appreciated.

Cheers

[Daleo]

Nice work there Leon. For beginners like myself, is the brake wire +12v? Just trying to work out how to wire in a relay to the reverse switch on the gear shift so it resets everytime I drive the car and don't have to explain the need to reset a switch to the missus.

Any help appreciated.

Cheers

Good job Leon; love a data trace!

It resets every time you start the car anyway. Mine sometimes goes for weeks without tripping the CEL, then other times it needs to be done twice in a day. I have no idea why.

You will need a latching switch, and when the CEL comes on; you complete the circuit, then hold the brake on enough to activate the brake lights for about 5 seconds. Otherwise you will need to build a circuit that feeds the wire a pulse (12v?) every 10 minutes or so.

Edited February 16, 2012 by Daleo

[slippylotion]

So will it work if I used a relay that completes the brake wire circuit when reverse is selected (to power the relay) with my foot on the brake to reset the CEL? This would be easiest for me as it will reset everytime I reverse out of the driveway.

Why would have Nissan used this throttle restriction?

Edited February 16, 2012 by slippylotion

[Commsman]

So will it work if I used a relay that completes the brake wire circuit when reverse is selected (to power the relay) with my foot on the brake to reset the CEL? This would be easiest for me as it will reset everytime I reverse out of the driveway.

Why would have Nissan used this throttle restriction?

All the ECU input is looking for is 12V, so it doesn't need to have anything at all to do with the brake pedal wiring. It could be as simple as using a wire connected to the reverse lights that goes into the ECU input (original wire cut away & taped up) so not even a relay is required. Of course there's a downside - you won't be able to launch at full power in reverse!

Why does Nissan use a throttle restriction? So we would have something to do to improve on their design, lol.

[PN-Mad]

Nice work Leon.

After I have the car tuned, I'll run a log on mine, post it and see how it compares. Stock they do have some kind of throttle restriction.

[Commsman]

Nice work Leon.

After I have the car tuned, I'll run a log on mine, post it and see how it compares. Stock they do have some kind of throttle restriction.

Really? Do you think it is because Nissan were trying to protect the driveline (from hoons like you, lol) or do you think the designers said "luxury wagon - let's make it as smooth as possible"? They certainly took that approach with the gearbox.

The thing the trace/s tell me is I need to work a bit harder setting up the boost controller. Hell of a roll off up top.

Edited February 16, 2012 by Commsman