NITROUS OXIDE ( nos / n2o ) advice forum

Hi.
Its now been 1 week since I had all my running problems sorted since the ignition module failure.
I feel that everything is not quite right when the gas is going in.
I use the car everyday for work and it goes like a rocket without any chemical enhancements.
Which is what you would expect from a st Fiesta.
But! when the gas goes in there is a very small delay until you feel the nitrous kick which is fine as it takes alittle time for everything to get through as it should.
As you get the nitrous kick the car starts to pull hard as you would expect. But when you start to rev over 4500k rpm and the gas has been going in for a few seconds, the engine starts to feel harsh and starts holding back.
another example is if I boot it from the lights with gas the car goes like stink but as the speed picks up and the revs get higher you can feel the power dropping off. Like a rather big flat spot.
The car pulls very well at lower revs with the gas and you can feel the gas going in until you go over 4500 rpm and then fizzles out.
This is mostly noticed on the motorway ie in 4th gear when the engine revs are just over 4500 rpm. The car is actually faster without gas than it is when you add gas. It feels like its holding back. Turn off the gas and it pulls hard again.
So. If I was to sit at 50mph and then floor it in 4th gear up till the red line, the car is faster up to the red line without gas.
Any ideas?

A friend of mine who works for superchips says because I am injecting the gas in before the throttle body its possible that the cars ecu is trying to adjust the settings for the engine which could be counteracting the nitrous injection. As its something totally alien to the ecu being injected in. But he is not sure as he admits that he does not know much about nitrous.

Ps running 25bhp. Jets 50 nitrous 25 fuel. No bottle heater.

what angle is your bottle at? is it possible that the liquid nitrous is flowing away from the outlet under acceleration and causing a huge rich spot. is your dip tube angled right? have you got a dip tube?

personally (and i'm no expert) i don't think this is engine speed related (although it might be) my reasoning for this is that my bike still pulls well on nitrous at 10k rpm.

have you done a plug chop? that may tell you more about what is going on.

Hi.
My bottle is sitting almost vertical but with a very slight tilt. The dip tube is facing backwards.
This is also happening with a freshly filled bottle.
The gas is working but only under 4500 rpm. Above that and the gas is barely noticeable.
My spark plugs are normal new ones. No modification.

i'm clueless really. Over to the expert to sort you out.

Holding back still points towards the ignition system. Check the plugs are gapped correctly for nitrous use, and if required, do Trevs electrode mod.

Could it be the car pulling timing when on gas

running rich higher up could also be caused by being abit on the rich side i remember reading on here at somepoint! mine done the same jetted 150/80. good surge then feel like it hits a flat spot. now jetted 150/70 it still does it but half as noticeable! still miles faster than without the gas either way!!

Did you experience the same problem BEFORE the ignition problem or didn't you have enough experience with it to have done so?

The FIRST thing you NEED to do is buy a heater, as the pressure is so low in our appallingly cold weather this year, that the bottle pressure is WAY TOO LOW, which means the volume of nitrous flow is extremely low, so the power will be down plus the mixture will be WAY TOO RICH which will further reduce the power.

The symptoms you've described could just be as a result of low bottle pressure, so I'd sort that first and as a quick/simple fix to prove the case, just fill a bucket with water as hot as you can get it and let the bottle sit in it for a while and then fit and use it in the car.

The result will prove if the cause is lack of nitrous pressure.

Hi.
Thankyou for all your replies.
I did not get much chance to test the nitrous before the ignition system failed.
Now everythings repaired I have had much more opportunity to test the system out and the cars not happy with it.
My pressure gauge in the car reads just under 50 bar during the tests.
The car still hates revving above 4500 rpm when under gas and I have no idea why.
Its alittle difficult to put my bottles in a bucket in water as I have covered them in self adhesive black carpet like on speaker cabinets.
Hides the bottles away from the wifes eyes. As I load up the shopping she does not even notice them now.
I have not been using the system lately due to the rough running and I feel that I could be doing more harm than good. I am starting to think about selling the system on and calling it quits with the nitrous.
I have even thought about selling the ST and buying a turbo charged car. Unless I can get the gas sorted out.
The car at the moment is running perfectly but I am going to dump the sportex exhaust that I bought for it. The car is so noisy that when you're on the motorway I have to wear ear plugs. Flipping thing.
I had to drive 100 miles this weekend to visit family and the amount of grief that I got from the wife
So I have been ordered to put the exhaust back to standard or else Unfortunately I have to agree with her now that I have sat on the motorway for a few hours. She had to wear my ear defenders that I use for work and I had to suffer the noise. I did end up with a terrible headache.
Sportex exhausts
I phoned Ford Saturday morning for a price. £250 for a new exhaust system + fitting by local garage .
I am not going to fit a pattern part to it. Timax or Bosal shite. Last a few months and thats it with those.

5 Bar is just over 700 psi which is 250 less than the system is intended to run at.

If you can't heat the bottle with water try putting it in the foot well and having the heater on full or in the engine bay with the engine running until you see a pressure nearer to 65 Bars.

It's a 99% likelihood that the effect you're experiencing is due to lack of bottle pressure.

Not that im not saying something thats already been said but having the bottle heated makes a HUGE difference! its really night and day between coming out in the morning and the bottle sitting around 600-650psi and having the heater on it for 15min while the engine gets up to temp and a nice 900-950psi. still putting a MASSIVE grin on my face each time!

Id say stick at it with the nitrous! I currently believing im getting more real world power than advertised due to how the power is delivered etc since my 230bhp + 75shot upsets my friends VXR8 till 3 digit speeds!.........Either that or he cant drive

either way 1k roughly for 25-75bhp with basic nitrous vs 4k on a turbo/supercharger.....i know where i stand!

I'm losing count of the number of customers that are achieving disproportionate increases in power, so I guess ALL our minor improvements are starting to add up, as this is a recent phenomena and would be expected if our efforts were worthwhile.

BTW we have an Italian customer who has recorded well over 300 HP GAIN from JUST 100 HP of WON and that's NOT a turbo car, which had it been I'd still only expect to see no more than double the claimed nitrous flow rated power.

Due to all the problems that I have had with my Fiesta ST I have decided to remove the system completely and call it a day.
For some reason my car does not like the gas.
I did give it one last shot before I removed the system. I warmed the bottle over night in my boiler cupboard and took a pressure reading before I put it in the car. Pressure was just under 68 bar (1000psi)
I gave it a bootfull and the car backfired and coughed again. Whoops! I thought it was just because of a new full bottle.
Nope! The car hated it. Every time I shoved the gas in the car just fighted against it.
The problem is that It has cost me alot of money with the ignition troubles.
So I have decided to remove the system for good and its now advertised on ebay and the forsale section in here.
As well as selling the system I have a lot of gas to sell on as well so I am selling it off for £5 per lb until by huge cylinder is empty.

Now what's really weird. Driving home tonight I gave the car a good bootfull from the traffic lights and the car went like total stink.
quicker than it has ever gone before with any chemical enhancements that I had fitted
The wife says its because the cars happy no more gas.

All I can say is that the gas has given the engine and cat a damm good decoke.