NITROUS OXIDE ( nos / n2o ) advice forum

Long before theoretical mixture BS was available I was getting reliable results from the following VERY SIMPLE method;

1) Static test at low power, adjust according to response
2) Step up the jets based on the same ratio and add a little extra fuel to be on the safe side
3) Repeat static test, adjust accordingly
4) Do a run with nitrous only activated from half track - kill engine IMMEDIATELY the finish line's crossed - inspect plugs
5) Adjust mixture & timing if required & as required
6) Do a run with nitrous only activated from quarter track - kill engine IMMEDIATELY the finish line's crossed - inspect plugs
7) Adjust mixture & timing if required & as required
8) Do a run with nitrous activated for full track - kill engine IMMEDIATELY the finish line's crossed - inspect plugs
9) Adjust mixture & timing if required & as required
10) Repeat steps 2 to 9 (excluding 3) for each each jet increase

Repeat steps 1 to 10 whenever ANY change was made that could affect the running of the engine.

You shouldn't carry out a static test above 25 to 50 HP jets unless you're prepared for the consequences, as you need quick reactions to avoid wrecking your engines BUT in experienced hands and done correctly it is safe to do a static test at BIG power levels to determine the correct mixture or at least put it in the right (SAFE) ball park.

its all in the book as well

Static test on higher hp levels:

Do you have a guideline for static test jetting and engine size?
How does engine size affect the test? You can use 50 hp on a small 4 banger and on a big V8.
The V8 is more than twice the size and you will still get a result.
I used 50 hp for my static test, engine was slowly reving up to ~5500rpm. I think this is ok but i never saw or did that test on a engine half the size.
So what is the difference?

I know this is just a basic test and you have to pull the plugs to be sure but i like to know this

Next question:
There is a video showing a static test on V8 and it was reving up fast as hell using some bigger jets than 50hp.
What was causing that? Is this behavior relatet to the engine itselfe or to the bigger jets?
I would think the engine would like to spin well over red line.

The static test is somehow still a secret for me.

Thomas

I never did a static test on my car when I finished my install. My 2008 CTR has an electronic safety feature preventing me from revving past 5200 rpm at idle and wrecking the valvetrain because of piston to valve contact at vtec.

I considered jacking up the front of the car, put it in 1 st gear, set the revs at 3000 rpm and do a static test with the 25 bhp jets. But because of my back injury I skipped this idea and proceeded to a roadtest.

First I checked over the system several times, checking all nuts, pipes and electricals.
I also employed my LC1 controller. I could see on the readouts that with the 25 fuel jet that there is initially a marginal amount of fuel going through the distribution block and pipes.
After each gearchange when applying the throttle it seemed as if the fuel flow is slightly restricted and needs time through the distribution blocks and pipes to reach the cylinders.

After I changed to a 50 bhp shot I noticed on the afr readouts that the 50 fuel jet has a more pronounced effect, richening up the engine especially in closed loop mode compared to the 25 fuel jet because of the enlarged overal fuel flow.

Back when I developed the static test there were no such things as AFR meters and engine management, so life was very simple.

AFR meters would have helped me a great deal back in those days of ignorance but I was lucky we only had distributors and carbs to deal with, rather than the ever increasingly complex management systems of today.

Spot on with the AFR meter Trevor. I would feel uncomfortable trying to fine tune the system just by looking at the plugs. I even have to disassemble half of the car it seems to reach the plugs.

I will give it a try with 100 and 150 hp and report back.

Thanks Trev

An AFR could be exactly what I need as the static test and road test didn't give any conclusions as to whether I was running rich or lean. The static test didn't happen simply, and the road tests showed the same spark plug colouring using 2 different jet ratio's

How do you determine the exact mixture requirement when you first fit one??? Is it to be 'taken' that whatever the reading is when running standard is correct, then you match that as closely as possible when adding the nitrous???

And after doing a little reading - will my cars Lambda sensor effect the readings when using N2O? As I'm thinking it may reduce the normal fuelling if I was running too rich and vice versa - or is it not quick enough to do either safely? Could this be the reason neither test showed definitive results if it was altering the cars fuelling to compensate for what the pulsoids were adding?

Cheers.

We offer one of the best AFR units available and we can give you all the info needed to achieve optimum settings when using it.

http://www.noswizard.com/product_desc.php?id=211

Cheers, already had a look at it. Due to the price I started having a read about them in general thus asking about the cars Lambda sensor thinking it was why I had no results from the tests I carried out - my thinking being it may be money spent on something that may not actually help unless I could bypass the current system somehow, OR, my system was doing all the work anyway in correcting the mixtures.

I'm not au fait on the subject so excuse my ignorance.