NITROUS OXIDE ( nos / n2o ) advice forum

you guys should look at getting egt sensors put in the exhuast. tells alot more of the story than just a a/f gauge...or even 4 a/f gauges. plus the race gas kills o2 sensors

Iv heard a lot that race gas kills the 02 sensors what exactly happens to them , do they go out of sync , or just stop working or sort of fade out ? its seams that in some systems they are being used more than just monitor A/F and being intergrated more into nitrous systems

nonsense trev...you can get a standalone megasquirt thats fully programmable for 440 dollars. they work just as well as a 3000 dollar accell unit and have MORE custom options. it also has nitrous control built in (even though i know most of us want to keep that serperate). just need to build a harness for it, and your good to go.


also, the center two cylinders are getting hot, so what kinda of cooling system does he use? i would suggest if he is allowed to use water, then to use and electric pump. it flows more than the motor does, and is easy to install.

if all else fails, switch to alcohol, it doesnt burn hot. just need bigger jets to make it work!


link to what dave needs
http://www.diyautotune.com/catalog/mega ... p-171.html

with nitrous ect the cylinder temps rise quite a bit , with a single wide band you tune to an average of all 4 , so if you on a almost perfect a/f you could be in theroy lean on middle 2 or just 1 , if the middel 2 were a lot hotter could the heat alone autoignite the mix in them 2 cylinders and not cooler ones, what im asking if a bike na runs leaner on middle 2 this would be a lot more on 300 shot of Nitrous if motor was close to a perfect tune could the extra heat alone push these 2 cylinders over the limit esp now with smooth delivery and denser nitrous Not saying it did im asking could it ?

If its accepted as you said the centre 2 cylinders are commonly a problem do you add any more fule to them 2 or just the same amount 2 to all 4

i would think the denser charge of nitrous would help cool the cylinder. i think there is something thats just not quite right with the setup...and its gonna be one of those things, when you figure it out, your gonna kick yourself, and the bike is gonna FLY

could also be the timing...those two inner cylinders may need 2 degrees more retard, the hotter charge could be burning quicker in those cylinders...

once again back to needing egt on each cylinder. and an entire day for the dyno..

Im not explaing my self very well sorry

but i still think the difference in the cylinders needs to also be considered

The ECU is only a small part of the overall requirements to convert from carbs to EFI and the R&D time would lead to another year of getting back to where he is now.

The RECENT problems have all been caused by EXISTING CRACKS in the center combustion chambers of the head. The mixture would have been fine but for that and there wouldn't have been any repeat melt downs, were it not for this ongoing problem, that Dave hadn't realised was any concern.

We DON'T need to change ANYTHING to run SERIOUSLY QUICK, all we need now is a GOOD cylinder head and a good gearbox, along with some good track time and by early next year he'll have the first sorted and we can only hope for the second.

good luck for next year guys

re converting to fi, trust me it's more complicated than just sticking an emu on! mine is running, but proving a pain to setup. hopefully the gains will justify all the hassle

my next job is fabricating an airbox, i'm starting to think they are critical

what kind of engine its it?

with the ecu im talking about all you need is a crank reference for spark and a cam reference for fuel. the ecu does the rest. thats just two sensors. then find some throttle bodies for it. i tell you what, ill save you guys the leg work and get you part numbers for everything you need, and that way you guys will have it. if you ever consider it, youll have the information all that waiting for you.

All sounds simple. But if u r going efi surely youd want temp compensatin etc? Then there is Re spacing or fabricating a new fuel rail and throttle linkage etc. Mounting fuel pump and two filters i.d want fuel pres and nitrous Sensors too machine a trigger wheel and get a sensor to woqk with it . . . . And when you have it all together the real work begins .

Exactly...... so as much as it's a better option if you're starting over and have the time & money and/or if what you have isn't working well, when what we have is working fine (in that department) and as we don't want to start all over again to find the 'sweet spot', what we really need to concentrate on for next year is getting a VERY GOOD cylinder head (a set of bronze skulls would sort out the problem), along with a recond gearbox and we SHOULD be good to get the job done next season.

air temp, water temp, volts, afm/map, timing signal/signals are required for even the most basic ecus

what ecu are you on about?

i run a old dta, batch fire so no need for cam sensors, i should think retro fitting them would be a real pain... i've been told sequential fire is only an advantage at tickover and for emitions, so of no interest to most of us

what i did was decide to convert by buying all the bits and getting all the work done one year whilst retaining the carbs etc, then getting it working over the winter and then sell the carb stuff once it was all working. that would have been sensible, i of course sold all the carb/ign stuff straight away and havent used the bike in a year!

this is why i love stock ecus and think replacement ecus are too over rated
fit an ecu off the same later efi model, and even if its not perfect a modern ecu will tune itself
does mean itll need the stock o2 sensor fitting too (which was missed off the original list)
any further tuning can be done by fitting a decent piggyback ecu

in this case a megasquirt in batchfiremode with jsut a reading off the crank would be ideal..sequential and big shots = bad anyways. putting on new tbs and fuel pumps is symantics..bolt it on and go.

im ready for em to bring that bike over to the US so they can get it right.

i considered transplanting a whole busa injection setup, but it worked out more expensive (!? breakers!) and more complicated (lots of sensors that are optional on the dta) than my dta setup.

appoligys for straying from the subject, but last time i walked thru the funny bike pit at the pod, an awful lot of them had FI.

then you see kev charmans bike and it looks like it only has a battery and a gas kit, still quick mind. cats and skinning ah?!

Now there been a lot more devlopment on the revos and fuel control , will we be seeing a new set up for Dave in 2010 or will the fact hes still on carbs bring up its own problem , i know he had engin issues and building a new motor for 2010 I still think he also still has/had fueling isues

Over his last few race meetings (and I even suspect before that), he's had NO REVO related fuelling issues and I'm totally confident that ALL his major engine failures were just due to knackered heads. His last fuelling issue was due to not having tightened the outlet fuel pipe nuts, which caused the engine to run lean, backfire and catch light and but for the Max Extreme AFR window switch (in use for the first time), the bike would almost certainly have gone up in flames BIG TIME.

It being a wet system is not now a problem, as thanks to Dave's involvement in the R&D program, we have all the original issues resolved. In addition to that we now know the AFR window switch works well, so that will prevent any unexpected issues causing a major failure in future.

We have Dave's REVOs and Max units here and we'll be inspecting, testing, updating and then further testing them, before sending them back to him in as new condition ASAP but to all intents and purposes, they will be much the same as they were when they were removed and the overall system will remain the same design. I'm so happy with the system design and performance, that I've just sold a replica of the system to a TOP US Pro Mod bike customer, who will be out testing long before Dave gets back on the track.

cool and i hope that means for 2010 we will see dave run from trialer to win every race in 2010 , be so very cool to see him at top , so much respect for Dave

I still have issues on how the heads/engins (and there were a few of them) got fucked in 1st place but that was last season , and for 2010 new engin build so in theroy we will all be at last race of season to toast dave championship

But if i was dave , would fit 4 egts one to each pipe that way easy to see if theres a problem got to be chaeaper than engins or head

The original failures were due to;

1) The first failure was due to a big end bearing failure (due to age) not being picked up on whilst being dyno tested (due to the extreme noise of the exhaust) and being run for long enough for the piston to SERIOUSLY smash the hell out of the combustion chamber and valves.

2) The second was caused by my EX mechanic IGNORING my instructions about which pistons to use and instead of fitting the matched set of 4 that I instructed him to fit, he fitted 2 pairs from 2 different sets without my knowledge. The pair he fitted against my instructions, didn't have big enough valve cut outs to clear the valves at full chat, so although there SEEMED to be clearance when checked after the build, as soon as Dave gave it some big licks, the excessive clearance on the valve stems (due to age yet again), allowed the valves to rock and make contact with the piston, once again leading to serious head damage.

3) The third was caused by a mistake with the head gasket assembly due to the replacement head having been modified in such a way that the head studs were free to wobble about excessively. This resulted in the combustion ring sitting offset to the bore by ALMOST AN INCH which meant the head was lifted in the middle by the thickness of the gasket while the other side of the gasket ran across the bore of the cylinder.
Believe it or not, I think it was in this condition when it ran it's quickest times, so you can imagine what it would have done had it not had this problem.
However, instead of a 6 sec run we ended up with another wrecked head.

So there we were with ALL 3 heads WRECKED BIG TIME and desperate to get something sorted, so we had all 3 ‘repaired’ over as quick a period of time as possible.
Unfortunately, after a comment/observation Dave made about a CRACK in the head he was using (between the exhaust valves), I was 99.9% CERTAIN that melt downs that happened AFTER THE HEAD REPAIRS (which happened DESPITE the mixture being believed to be too rich), were ACTUALLY caused by the heads not being repaired correctly and/or the heads (valves) not being assembled correctly.

I never was convinced that such damage could be caused by being OVER RICH, ESPECIALLY BY A RELATIVELY SMALL AMOUNT and a cracked head with badly seated valves, is a much more realistic explanation.
Whilst the Lambda sensor was showing rich OVERALL, it is more than possible for ONE or TWO cylinders to run lean, due to cracks and/or leaking valve seats and not be detected.

Now some people will no doubt accuse me of trying to shift the blame away from the nitrous system but I’M the ONLY person who knows ALL THE FACTS and has the EXPERIENCE to judge the OVERALL run of events CORRECTLY, so **** em!!!

If I had ANY doubt about the above run of events and thought the REVO system was in ANY WAY to blame for ANY failure, I MOST CERTAINLY WOULD NOT be supplying a replica of the system to a TOP US Pro Mod customer, YOU CAN BE SURE OF THAT!!!!

So new heads? or ali bronze skulls?

How about switching to the ward head,back to 2 valves so no hot spot between the exhaust valves,there is also a new puma 3 valve head.

No doubt Dave would go for the best option if resources were unlimited but as they are extremely limited, he may have to make do with what he has.

I'm considering buying him a skulled head but his last comment was that the ones he had (which would need the skulls fitting) were probably no use, because they had been skimmed so much, so I'm not sure what to do now.

One principle I have always worked to and which has no doubt contributed to the delays in achieving the success my products deserve, is that it's a bigger achievement to be top dog on the back of a shit bike/car, so it's not a black and white choice.
Were we to achieve the results I'm sure we can, by just using GOOD, albeit very well used everyday parts, then the achievement would be 2nd to none.

There are few of us on here who can just buy the best bits regardless,most of us are on tight budgets,which is why we're here asking questions.
So we can appreciate what you're saying about good parts.

Sometimes you just have to bite the bullet tho I don't suppose good GSX11 heads are that easy to come by anymore,they've all been dragraced to death!

Which is another reason why I pushed the WET option for the REVO system, because it's a cheaper option for anyone without dyno facilities.

Dave was VERY LUCKY to find the spare head he did and although I have a spare STOCK head, the conversion work would costs $1,000sssss.