Fuelling mods - Nitro-X and Kev mod
 

Hi,
This thread is a continuation of a thread which started off in the Newbies Reception Lounge. The discussion was getting a bit too deep and detailed for that forum, so I propose to continue it here.

I can't move the previous discussions (only Admin can do that) so here's a link to the previous thread in the Newbies Lounge: http://www.xt660.com/showthread.php?t=19581

Hi oldf4RT,

So tell me a bit more about your fuel mod. You added a variable resistor (like a Kev Mod) but it's a 1K pot? Have you wired that in series with the IAT (intake air temperature) sensor?

If so, it sounds like a good idea because it'll both measure the actual ambient air temp, as well as allowing you to "turn down the temperature" to increase the fuelling.

In the previous post (in Newbies) Pleiades mentioned that the current Kev mod is 0 - 10K ohms. I'm therefore guessing that it's probably wired in place of the IAT, not in addition to it? According to Service Manual the standard IAT has a resistance of 2.21 - 2.69K ohms at 20C.

I've installed my Nitro-X module (as per instructions) to replace the IAT, so the ambient temperature no longer has any input into the ECU, but the more I think about this, the more I see it as a disadvantage. I like the idea of wiring the modifier in series with the IAT so you get the benefit of both.

The Nitro-X module contains four resistors which, through setting a four-position DIP switch, allows a variable resistance from 1.259K to 6.830K ohms. From my tests, this allows selection of inlet air temperature from +37C to -4C. Choosing anything above actual ambient temp (say 16C today) will therefore weaken the mixture, of course, so that's of no benefit for our purposes, but choosing anything between 16C down to -4C will progressively richen the mixture.

When you say "Sometimes I think it works and some days not" it makes me wonder if this is due to the change in the ambient temperature? If I set my NitroX to fool the ECU to get 16C when the true ambient is 21C then I'm getting 5 degrees of enrichment, but if the true ambient falls to 16C then I won't be getting any enrichment at all!

I don't really want the hassle of continually tweaking the setting according to whatever the ambient temperature happens to be that day, so that's why I like the idea of wiring the IAT in series.

For the most part, my bike is running really well now (anything over 5-10% throttle) but I still have slight glitches at small throttle openings, in fact as you so aptly put it: "...can't get clean throttle response coming off closed throttle entering corners. Very annoying as it upsets balance and also my confidence."

I've seen little on the Nitro X,the time honoured way is DNA 1 and 2,Kev's mod,remove snorkel,drill holes,go to a PC if you want a touch more go and also gets rid of the snatch.

It's the route I went and I've a Kevs fuelling mod if you want to loan it to compare.

Dave,

You're exactly right. My 1k resistor is wired in series with the air temp sensor. When monitoring via the dash display it gives me zero to -8 degrees adjustment against CURRENT AMBIENT temp. This means that when set to say -5 it fools the bike and makes the mixture richer and will always do so at whatever the ambient temp is. I believe that the statement that the current Kev mod is 10k is incorrect. It is 1k.

My hunch (and it only a hunch) is that even with this active - when at low throttle openings the oxygen sensor reads the exhaust gas and cancels out the air temp adjustment that we have made and thus causes hesitation due to weak mixture.

I'm away in the US for a couple of weeks now and when I come back my plug and play oxygen sensor eliminator will have arrived from Kev and I'm hopeful that this will work. If not then a Power Commander will be the only way.

The new plug and play oxygen sensor eliminator is more sophisticated than the current one and is also easier to fit as it plugs directly into the harness in series with the O2 sensor. It adjusts the O2 sensor signal to richen up the mixture rather than trying to cancel it out altogether.

This is Kevs reply to my questionregarding the cheap,plug in O2eliminators you can buy on ebay. It's very much consistent with my hunch about the O2 sensor. Do you understand the closed loop and open loop ? I assume when closed loop the circuit is completed by the O2 sensor and gets feed back from it and when open it doesn't ?

The resistor type O2 eliminators do not work on the XT660X,R or Zs we have
proven this on the Dyno, the only 2 that do work is Dynojet's O2 Optimizer &
my O2 eliminator. I now have a new plug & play version O2 eliminator for the
X & R models, photos attached.

My fuel mod, a PCV or PCIII can only adjust the A/F ratio in the open loop,
as soon as you start cruising the closed loop comes into play & takes
readings from the O2 sensor & will lean the A/F ratio out again no matter
what fuelling device is fitted to your bike. To completely control the A/F
ratio you will require an O2 Optimizer or one of my O2 Eliminators[/COLOR]

Even though I have two bikes with PC's fitted I wouldn't buy one now unless it's cheap,my K1200 which has dubious fuelling at best has needed sorting for a long time,this last week has been a 9.9 on the Richter scale because aftermarket fuelling is changing!!! the days of bolt on fuelling mods are on the way out,the difficulty for me was beleaving it, which I didn't a week ago,it's been a shock to say the least.

No, the Kev fuelling mod is/should be wired in series. It does not replace the IAT sensor.

Your hunch is right - the closed loop governs fuelling up to 3000rpm, small throttle openings and while on the cruise.

Correct the air temp is always been read even in the closed loop, but any adjustments made to the AT sensor will be over ridden by the closed loop circuit.

My fuel mods have been update with 4 different versions over the past 6 years it is connected in series to the AT sensor, I know of better ways to build the mod but it's all about the cost of the mod in the end, the main purpose of my mods is to make them as cheap as possible to the guys that can't afford expensive fuel mods. I removed all the info on how to make your own Kev fuel mod from the open forum because there was member on this forum that decided he would mass produce my fuel & spacer mods & start to sell it for himself. The info is still avaiable to supporting Forum members to make their own through the ASK Kev section.

I always offer proof of my mods by means of Dyno runs or other means.

http://www.youtube.com/watch?v=glkdBO8aZm0&feature=channel&list=UL

Part of a discussion we are having in the ASK KEV section at the moment were I cover this type of info in detail.

There are 2 sides to a fuel map, closed & open loop circuits.

A Power Commander or any other type of fuel mod can only adjust the fuel map in the open loop, the open loop circuit is when the the ECU sees sudden acceleration, any RPM above 4500rpm & all throttle openings over 20%, cruising or not cruising.

The closed loop is used for emission control, it comes into effect after a coolant temp of 70 degrees C, when the ECU sees a constant throttle opening of below 20% & below 4500rpm, the ECU takes voltage readings from the O2 sensor & will lean the A/F ratio out until it sees a A/F ratio of 14.7:1.

The resistor type Eliminators do not work we have proven this, at the time of proving they do not work Dynojet pulled all the XT660 resistor O2 eliminators from their for sale lists. The ECU constantly looks for 0 to1 volt square wave signal, by unplugging the O2 sensor & fitting a resistor it sends a constant voltage signal to the ECU, after a few min's the ECU see this as an corrupt signal & then constantly switches the A/F ratio up & down, in this state the bike is not tuneable. Below the You Tube test is with a resistor type eliminator connected & the A/F ratio has been data logged.

http://www.youtube.com/watch?v=ZwTfuwZZ848&feature=channel&list=UL

The only 2 types that have been proven to work are Dynojet O2 Optimizer & my O2 eliminator/controller.

I have 2 types of O2 eliminator/controller one completely turns off the closed loop circuit & the latest type controls the O2 sensors voltage outputs.

By controlling the closed loop circuit we are able to reduce the surging when you are cruising, with one of the latest O2 devices when the ECU switches between the open & closed loop circuits the transition is much smoother as the A/F ratios are closer to each other, see table below.

Open loop for most HP & Torque= 13.2:1
Closed loop A/F ratio = 14.7:1
O2 Optimizer or kev's latest O2 controller = 13.6:1

I think what he (oldf4rt) was implying with his "hunch" was that whatever he does in adjusting the fuel mod the closed loop will always cancel out its effect (that of adjusting the fuel mod), I don't think he meant that the ECU isn't taking a reading from the intake air temperature sensor?

Thanks very much for all the detailed feedback and answers fellas; I now have a much clearer understanding of how the Kev Mod works, as well as a better understanding of the closed-loop/open-loop modes and when they kick in. :)

So, it looks like I'm going to be ditching the Nitro-X in favour of a Kev Mod. As I suspected, a significant disadvantage of the Nitro-X is that it dispenses with the IAT and therefore disregards the ambient air temp. As you've pointed out, the Kev Mod takes that into account by wiring the two together in series.

I briefly considered rewiring the Nitro-X in series with the IAT, but the resistance values aren't suitable for that, plus you can only tweak the value in steps anyway, not continuously like the Kev Mod. Way to go, Kev!! :041:

Look forward to hearing how oldf4rt gets on with the plug-n-play O2 eliminator - I reckon I may end up going that way too.

Thanks for point that out I now see what he means now I have corrected my statement, as mentioned the closed loop will aways over ride any fuelling devices.

Yes that is what I meant but perhaps I didn't explain it very clearly. Wow you boys have been busy on here today !

Thanks for explaining the closed/open loop issue. Each piece of the puzzle makes it easier to understand what's going on.

Can't wait until I get back home to try the new O2 "adjuster" (is that a better term for it than eliminator ?

Popped into my local Maplins this morning and got the bits necessary to knock up a Kev Mod.
Been out riding all day, but after a bit of drilling, filing and soldering in the "man-cave" late this evening, the Kev Mod is now done and ready for fitting one night later this week. :) The Nitro-X will come off and be consigned to the bin!

http://i247.photobucket.com/albums/g...cn2984_sml.jpg

Thanks again for the info guys!

:eusa_clap::YouRock:

Trying not confuse everyone I am calling the new 2012 O2 mod a O2 controller, as it does not eliminate the O2 sensor.

Looking good, my mods come completely sealed with an O ring around the Pot shaft, with the box & wiring all sealed up, the UK weather will kill the mod if it is not water proof.

Good point Kev - mine's not weatherproof, although I was planning to fit it under the seat anyway. However, it'll do the job for now, just so I can compare this mod against the Nitro-X, and as the bits only cost me a fiver, it's a cheap way for me to try it out against the Nitro-X.

I still reckon I'm going to have to go for the "O2 Controller" to achieve the response I want. Talking of which - I tried to find some details of the O2 Controller in the online store but couldn't find it there - too new I guess :)
How much is the new O2 Controller (posted to UK)?

Cheers,
Dave.

I would be surprised if you can find any info on the O2 controller as it is all in my head, it has taken me a fews years to get a working version & won't be releasing how I have done it for a while. The new mod can only be ordered via PM at this stage, if the mod is in demand then it can go into the XT660.com shop. They just take a fare bit of time to make up so I rather control the sales at this stage, let see if the mod is in demand the last O2 eliminator mod died off, at least I can say I have conquered the O2 closed loop circuit.

The O2 controller mod is completely expoy together so it will have to be broken apart to find out what I have done.

Hi Kev,
Just to clear up any misunderstanding, I have no intention of dis-assembling or reverse-engineering your O2 controller, I just wanted to know if I can buy one from you, and how much it would be.... :)
I found the price for the Kev Mod in the online sales section, but I couldn't find the O2 Controller...
Thanks!
(PM sent)

No misunderstandings, the main reason for sealing the mods up is so they last for ever & are 100% water proof, 2nd reason is to protect my mods at least for the first few months before they get copied & mass produced by someone for self gain.

The latest vesion of my mod book does lists in detail how to build your own 2010 O2 Eliminator & where to buy the parts from, which is the only O2 mod in the world that actually turns off the O2 closed loop circuit, this new O2 controller controls the voltage.

Kev... I have your fuel mod on my bike..
When you'r O2 controler arrives can I run with your
fuel mod...
Still trying to get my head around all these wirey things...

You sure can.

The O2 controller tunes the closed loop circuit.
The Kev fuel mod tunes the open loop circuit.

Thanks for asking that question Petenz as I was just thinking about the same thing today.
And thanks Kev for the answer.

Just on one another thing Kev, would I be correct saying that the O2 controller should get rid of that annoying occassional stall.

By the look of the figures you posted it will be much much better when switching from open loop to closed loop.

The main function of the O2 controller is to tune the closed loop, if the cutting out is been caused by the closed loop being to lean lets hope it fixes it, those results unknown at this stage.

Copy below of a message I just sent to Kev. Pretty self explanatory.
Very happy XTX owner !

Also new Dunlop Sportmax Mutants are excellent. May just be because they're new and the old tyres were knackered and mismatched (Michelin fornt ,Bridgestone rear).


Kev,

Its been a long cold and wet winter here in England. I finally got out last week for a couple of hours and was astonished how well the Xtx ran.. It was first proper ride since last autumn with your O2 controller. I also fitted a DNA Stage 2 before the ride and suspect that this has contributed considerably to how well it runs.

No hesitation at low throttle openings making it very confidence inspiring to ride.

Current mods list:- Co set 25 up from standard, Kev mod at +8 degrees, Kev's New O2 controller, K&N filter, DNA Stage 2, Snorkel still in !, MTC Exhaust cans and link pipes,
WHAT A BIKE IT IS NOW ! If Yamaha sold them like this they would be everywhere.

I'm going to leave it pretty much alone as it is now. I might try the snorkel out but it's so good I dont want to tinker too much. It feels like it needs another gear now !

Only one thing still on my mind - other than doing a spark plug colour check how do I know when the Kev mod is adjusted correctly and mixture is not too lean or weak ?

Thanks for all your help - I've finally got the bike I hoped for !!!

As per PM. Thanks for the feedback, glad you have a much better ride now.

You need to adjust the mod as per the mod instructions as they were tested on the Dyno to get the A/F ratio settings & you will be fine, if you need the tuning instructions again PM me your Email address again & I will send them to you when I get home tonight.

Thanks for this information. Most of it is over my head, but nice to read. I installed the Kevs mod to my bike that had the original pipes cut/gutted and re-welded. Was initially happy with the mod, but it was only making a very limited improvement. I have since purchased some new mufflers and link pipes. I am still having issues around the 40-50K speeds with poor fuel delivery, and back firing is still an issue. I have made adjustments from 0.15 - 0.45(imagine a clock face), it's currently sitting at .45. I have just bought a Nitro kit, but after reading this seems a waste of money.
The bike has a stage 1,2 DNA kit, but maybe the holes that were cut in the sides of the air box were too big and the adjustments are not adequate?
Any help would be appreciated

What model & year XT660 are we talking about? As the XT660 that are 2007 model on wards with O2 sensors require an O2 controller to fully control the A/F ratio.

Have you blocked off your AIS pipe to reduce the popping when the throttle is closed.

I would increase the fueling to 8 O'Clock with all your mods.

Fuelling issues
 

My bike had poor fuelling at low throttle openings and also in the transition from closed to low throttle openings such as feeding power in gently when mid corner or low speed cruising. Kevs New O2 Controller fixed this for me.

Your set up looks similar to mine but don't know model year of your bike. Mine is 2009 with Oxygen sensor in the exhaust.

The Kev mod adjusts the fuel mixture to prevent running weak but didn't (can't ?) cure the poor fuelling on its own.

It is worth persevering because the bike is a joy to ride when the fuelling is fixed.

Good Luck.

Thanks for the replies.
2005 XT660X

I saw the bit about AIS and blocked it off. Also adjusted CO up 8 places. Yes Kevs mod is sitting at 45(9pm). I will take it for a ride this afternoon.

Coming from a Ninja 250 this thing is just great. So will try to sort it out. Really want it running nice so I decide if this style of bike is the way forward. But the seating position is god dam brilliant. No pain in the wrists or arms any longer and more road presence.

02 Controller? Haven't seen that.

2005 XTX ECU info, if you have a 00 ECU is is very hard to get rid of the surging, a fuel mod will help but you will never get a perfect ride with a 00 ECU.

http://www.xt660.com/showthread.php?t=8546

Also check your rear sprocket holder rubbers there should be no free play in them, what is the condition of your chain & sprockets?

Checked the ECU, it's 5VK-8591-01.

Took it out Yesterday, with CO up 8 places & AIS done. Seems to be better. Have increased the CO up another 2 to make that 10 in total. Any limits on that increase? Still getting a lot of back fire. But that doesn't really! worry me too much. It's more the fuel delivery.
Will get back on how this runs again.

Maybe I should put my dB killers back in.

A 01 ECU would have been changed under warranty.

Ok, so I took it back out this afternoon. Put the fuel back down to eight o'clock. Big improvement. Stopped, put the fuel back up to 9pm, this seems to have settle things down even more. The surging has reduced by about 80-90%, I can now happily run along in 4th at 50km and have no issues.
So, the setup is as follows:
*Kevs fuel mod at 9pm
*CO increased by 10 points
*AIS blocked
*Stage 1&2 Filter
*large triangle holes cut in filter box & snorkel removed
*Some nice scorched titanium mufflers from www.spengineering.co.uk

This is about all the performance mods I will do on this older bike. But at this stage it has made a huge difference to how it rides compared to first time I jumped on it.
Hopefully this ridiculously long dry spell continues a little longer😄
****** the cows

Nice one mate.