NITROUS OXIDE ( nos / n2o ) advice forum

Hi All

New to this forum but I've been toying with the idea of fitting a 150i kit to my BMW Z4 3.0i for some time now (about 2 years), but must admit up to now I have not really been able to justify spending the money for a bit of fun on a car which is fairly quick anyway and that I only use in the summer , so im really looking for some persuassive comments to cajole me in to doing it, has anyone any experience of this system on my car. I have been reading Autosri's threads about his 330i 3 series which im pretty sure has the same engine and has been encouraging, although he has not been entirely problem free regarding his ignition system.

Im also trying to understand the performance gains which appear to me from reading some of Trevors comments, that being a 75bhp shot of nitrous is more effective that 75bhp from conventional tuning due to the fact that the extra power and torque gains are available throughout the rev range, so does that mean theorectically that my Z4 with a 75bhp shot giving around 290-300bhp, would be as quick as a Z4M with 338bhp?

Anyway feel free to pile in with your comments cos Im gonna have a few questions no doubt

welcome to the forum

Im afraid i cant offer any advise on the BMW, but i can tell you about my nitrous experience, I too was pondering on fitting nitrous to my car for a long time, before going ahead and doing it

I have an 09 plate mk7 fiesta zetec s, which looks very sporty with its factory fitted body kit, 17" alloys, but really underneath its just a std 1.6 fiesta with 120p.s (118bhp) a fiesta ST wannabe if you like...

The car drove nicely, had a great chassis, handled well, but wasnt fast by any stretch of the imagination... I did what a lot of people do, and joined an owners forum and read all the posts about going about making it go faster...

The first purchase was a J1 induction kit (£200) to replace the std air box, which according to general consensus , was incredibly restrictive, it turned out to be a bit of a disappointment, now my car made a racket and if it was making any extra power it was hard to really notice... it kinda sounded faster lol.

according to the forum, the next step on the tuning ladder would be fitting a full milltek stainless exhaust system, comprising of a 4-1 exhaust manifold, a 200 cell sport cat and a single box system (£1000) this would take the power to 140 p.s, so i found the money and had it all fitted... now the car really made a racket, at times the noise is a little too much for me... and to be honest was also a bit of a disappointment... the car felt slightly faster but nothing like i had hoped for... there had to be another way.

i did some research and the next step would of been piper cams and a remap to give 155p.s, for another £1000 or there was a drive in drive out supercharger conversion for 170hp for a whopping £3250

As you can see i had already thrown good money after bad trying to make this car a little faster, then i investigated the possibility of Nitrous, which led me to this forum...

Turbobox and Trevor (Noswizard) patiently answered all my newby questions, put my mind at rest over fears of my engine blowing up, and i went out and purchased a 150i kit for my car, I fitted it all my self with help on this forum from turbobox and Trevor who were there offering advise and tips along the way as and when needed.

So the day came for me to take a drive to the Wizards of nos head quarters for them to look over my install, fill my bottle up do the static tests for me and the first test drive.... to say i was a little nervous was an understatement... every man and his dog told me (wrongly) Nitrous will blow your engine up... after many bottles of nitrous going through my engine its still as sweet as a nut, infact the engine feels and sounds much nicer when im spraying than when im not, which is something i have read elsewhere too.

Anyway... I stuck with the 25hp jets for the first couple of bottles, just to get used to using the system and boy even on 25hp jets my car kicked ass after a couple of bottles had gone through my engine I upped the jetting to 40hp, the difference was absolutely stunning... the car is now very fast, you activate the nitrous and it just goes!!! the amount of cars i have shocked out on the road is incredible, i have kept up with cars that i shouldnt even be sharing the same tarmac as

Finally I had spent money on something that actually did what it said on the tin, If i did it all again... I wouldnt of bothered with the silly induction kit and exhaust system, i would go straight to nitrous

I have since purchased the WON bottle heater, which you will need if you want to use nitrous in the winter months, for summer only use you can get away without a bottle heater...

In summary 1 very pleased Nitrous user... be warned though... its very addictive

Great posts guys and very informative...and helping to swing me over in the nos direction.

Turbobox, The ignition problem with autosri as I recall he couldnt get the recommended spark length from the standard coil packs and had to piggy back some sort of boosters to achieve it, but this may have been when he went to the direct higher power kit 125bhp, should the standard coil packs be up to the job for the 75 shot?

My Z4 has a full BMW service history with 62k miles and is sweet as a nut so even though Trevor recomends a number of tests before fitting nos, I dont have all the test equipment but feel confident about the mechanical state of the engine...that said I did have 2 coil packs go down this summer but they are not expensive if I need another 4!

So you dont think I would need a heater for summer use, what would you say the min ambient temp should be before needing a bottle heater?

I am a service engineer so am quite confident about fitting, but might need some advice on the TPS option I need on the car. Like on the static test how do you set the TPS up to activate at 2000rpm so that you can determin the correct A/F ratio with the jets, and if anyone knows the exact colour wire for the 0-5v on the TPS would save me stripping wrong wires etc, im assuming that i would have to strip wires and wouldnt be able to get a probe on the connector block.

The thing is with the british summers, they are a bit unpredictable... during last summer my bottle pressure varied between 800 psi to 1000 psi on very hot days...

The bottle heater will heat the bottle to 1000psi before automatically switching off... so some days it wouldnt be needed, on others it would heat the bottle up to the last couple of hundred psi.... when autumn hits and the outside temperature drops quite rapidly you could expect the psi to drop to 600 or 700 psi... on a day like today in december 500 psi.

now ive used a bottle heater i would always factor one into a nitrous install, but some people are put off by the extra expense on top of the price of a kit,

you can get away without running one in the hotter months.... but the hit of the nitrous will always be better at 950-1000psi.

It does sound like the heater is the way to go eventually for maximum efficiency as you state and even though i live in the South summer temps can be 15 degrees one day and 25 the next, I must admit though I never really go out with the roof up so need about 18-20 before i do, I cant be doing with flying jackets and the like lol... then again we do get some nice spring and autumn days too and im sure the addition of the nos will re-kindle my interest

Turbobox, Im probably over thinking things but another question about the static test, when you first do the check to see if NO2 and fuel is coming thru, for the fuel presumably the engine will need to be running for the fuel pump to be on, if this is the case wont the inlet be sucking in air from the disconnected crossfire injector or does this small amount not really matter, sorry im a bit of a perfectionist so like to know the in's and out's of a dog arse!

if your talking about just checking whether fuel and nitrous are being issued from the crossfire injector prior to doing a static test, then most modern cars these days have an electric fuel pump which is activated by the ignition switch. when you turn the ignition on you should here a quiet buzzing or hum, thats your fuel pump working.

in any case... the ecu will detect a small air leak and compensate, it wont do any harm to your engine for the time it takes to establish a reliable flow of nitrous and fuel.

If the case is simply verifying nitrous and fuel flow through the injector, then it can be done by removing it altogether with the engine off but the ignition in the 'run' position and the nitrous bottle off. The fuel system should be pressurized enough to have brief fuel only flow to the injector, then the same can be done with the nitrous side by opening the bottle then retesting where there will only be nitrous flowing due to depleted fuel system pressure. This will also verify that the system is working without the danger of both fuel and nitrous flowing and possibly combusting from a stray source of ignition like a fag (cigarette for us Americans).

This test is merely an operational check and not the static test.

A friend of mine on a visit to America found out that saying "im just going outside to smoke a fag" has a whole different meaning than in the U.K

That is an unfortunate truth isn't it?

Ah ok that makes sense, thanks for the advice.

I think im bi-linqual due to the fact ive been brought up on american tv detective programs Columbo, Ironside, starsky and hutch etc I think my favorite (notice the spelling lol)..american words are fanny and spunk which here is.... well you probably already know haha...

Probably gonna wait till spring till I order a kit though, cos i aint got a garage

I can't wait to hear about the 48 hr grin

Just ordered Trev's book:)

Good man