NITROUS OXIDE ( nos / n2o ) advice forum

Hi first post and looking for as much info as possible please as this is all new to me! I've never considered fittimg a nitrous kit before but it could be the ideal solution for my car?

Sorry for the long first post!

I've got a 2005 Saab 9-3 v6 Aero, this shares the same 2.8 v6 turbo engine and F40 gearbox box as the Vectra VXR. I've been doing some research on the forums and I think there's two VXR's with the WON kit fitted now, so I know it's possible on this engine and has had good results (owners seem really happy anyway!!) I know of one Saab 9-3ss with it done but it's a highly modified 2 litre engine.....so pretty keen to get mine done!

The cars currently modified with a JZW stage 1 remap producing around 320bhp & 410ft/lbs. Suspension/brakes are done.

The next stage of mods will be an uprated clutch with Quaife LSD (more on that later as I'm a bit woried about the extra torque from the NOS and how it will effect the clutch higher up the rev range) Clucth will probably be an uprated Sachs unit plus solid VXR flywheel (possibly from Regal) and hold 460ft/lbs.

Once the clutch is done I'm fitting a larger 3" DP plus a full 3" twin exit system, bigger Intercooler (90mm core Lancer Evo type) then a stage 3+ remap and this should get around 350-360bhp & 450ft/lbs (give or take what maps loaded as I have regular, revised & aggressive maps to choose from)

I was thinking of upgrading the turbo to a Billet 20T upgrade (td04) which would have seen around 450bhp and 550ft/lbs but would also need a better clutch here as the sachs upgrade I'm looking at wont hold 550ft/lbs! And bigger 550cc injectors (bought)

Engines internals are good for 550bhp, so I'm well within Pistons safety limit here.

Sorry for rambling on but that's the plan at the moment!

What is like to achieve with a WON kit is this.

If I stick to the same turbo this seems to run out of puff slightly around 5k, still pulls but I think due to the way it's been mapped I'm getting a huge slug of torque lower down then it's easing off higher up. A 20T tune sorts this and it pulls hard right up to the redline but also has a bit more turbo lag (not much though)

So the plan is to fot the WON kit but only use it WOT above 5k for gears 3/4/5/6 where I feel it needs that extra shove at higher speeds.

Couple of things I'm worried about.

Clutch
I know this sachs clutch will hold around 460ft/lbs but realistically how much extra torque could I expect from 25/50/75 & 100hp jets? As its not getting used it il at least 5,000rpm will the clutch be ok here? I'm getting peak torque around 3-3.5k so I'd imaging if I used nitrous here I'd kill the clutch in no time, but as its eased off above 5k I'm hoping it'll be ok and won't slip!

Injectors
I've bought some Bosch 550cc injectors already so is it worthwhile fitting these or no necessary? My standard injectors are good for 360bhp but not sure if these need upgrading if I added say another 100NoS?

Which wet kit?
I think you sell two kits for the v6 and after some reading I'm better off with a wet kit vs dry? Is there much of an advantage going for the SB150iS6 over the SB150i6 kit? Bearing in mind when I sell the car in a few years I'll be removing this kit for the next car So is there many hardware changes/modifications to fit the 'S' kit over th other?

Torque
How do the torque figures equate to the BHP per jet size? Would 50bhp jets = 50extra FT/lbs or more/less? (Again thinking about clutch longevity!)

Loads more questions but can anybody advise with the above please?

Really excited about going this route! Bit different to the normal big turbo route and I think more beneficial to me. Plus it sounds cool

I've been reading up more on this (and have the book coming to get more clued up! )

I've been getting confused here and realised the SB150i6 is a direct port kit which I didn't really want and it's the SB150i kit that I should be looking at instead. Mainly for ease of installation (cost) plus it'll be easier to remove when I sell up and put the car back to standard. Much cheaper to just get a new £50 intake pipe vs two intake manifolds at £250+ a pop each!

I'm giving sachs a call later to see if they can give me a better idea on how much extra torque their uprated Clucth will hold or if they can supply a stronger pressure plate....and I'm hoping adding 50-75hp nitrous above 5k won't be much an issue as I think the torque would have tailed off around 4k. It won't be used all the time anyway, just for the occasional bit of fun and scaring the missis

But still trying to figure out how much a 25/50/75 shot of nitrous would equate to in ft/lbs?

Couple of things I've been reading up on, and it looks like gettimg the bottle warmer is essential as I live in sunny South Wales! Also I'd be getting the braided line under the car vs run through the interior.

Purge kit.....would this be worth getting? The car will never be tracked but wouldn't mind taking it to a strip to time it's 1/4 mile with/without nitrous. But more of a concern is the car will be parked up 2 weeks at a time and not touched as I work away. Would a purge kit be beneficial here as its standing a couple weeks?

Controler. I'll only be really using this in 3rd gear and above (6 speed manual) and only above 4.5-5,000 rpm to redline as it'll probably lunch the box lower down. Which controler should I be considering here please as ive noticed a couple here for sale?

Fuel injectors. I might be getting confused here but I think larger injectors would be beneficial on a dry kit but what about the wet kit 150i? My standard injectors will be maxed out once I tune to stage 3+ so would it be safer to fit the larger ones to stop it running lean top emd when I use the nitrous or doesn't it matter?

Lots more to ask but I'm trying to figure out as much as I can through snippets of info here & there!

Hi Dai,

First of all your car should pull higher rpm when using the WON nitrous system as you require, as long as the limiting factor of your turbo performance is not due to the aspect ratio of the exhaust side being too small.

The system that will suit your purpose is as you've concluded our SB150i as long as you only have a single/common air feed pipe to all 6 cylinders. this system is supplied with nylon nitrous supply pipe (which is MUCH better than braided hose), that should be run inside the car. As long as you choose this option you will not need a purge kit but if you choose our export/race version of the SB150i system (with braided) you certainly will need a purge kit.
Although it would be beneficial to add a purge to bleed down the pressure when you are not using the system, it's not essential and you could bleed down the pressure by briefly activating the system (while the engine is running), after shutting off the bottle valve. Whatever other choices you make, a heater will be beneficial.

With a Max Extreme progressive unit you'd be able to select which gears you used the system in and you'd be able to select low settings that you probably could use in the lower gears, while selecting higher power settings for higher gears. In addition to the benefits of progressive control, the Max offers a range of safety features that any nitrous user would benefit from and for your application our X1 would be adequate.

There is no need to change your existing fuel injectors with our SB150i as all the extra fuel is added through the nitrous system itself.

With regards to your clutch, it is more likely to suffer a problem at low to mid rpm than high rpm, as it's torque Vs load that makes them slip.

Thanks Trevor.

Maybe a silly question (as I'm very new to this and the safety side of things! But need to know) Is there any danger running the hose through the interior? I'm guessing it's ok but we're planning on kids this year and my misiss would kick my butt of anything went wrong inside the car!

Also I've been looking at a few youtube vids to get a better idea on how things work, is there a safety release valve that squirts the gas out of the car if there's a problem? I'll have to find the link but I think it's was a NOS video that blew the gas through a pipe exiting under the car. Different system though so not sure how similar they are.

Everyone I've spoken to has said to fit a WON system though as it's the best in the UK...so I'm pretty satisfied and convinced it'll be safe! Just want it clarified by WON please.

If the cars not used for 2/3 weeks at a time what would you recommend doing here when last using the car and parking it up, and then starting it up again a few weeks later? Is there a set sequence to go through so I don't damage anything?

I've got loads of questions but don't want to swamp you with them! But would I need a bigger/uprated fuel pump, fuel rail & fuel lines to run the 150i kit or good to go on the standard ones?

The turbos standard, the only mods wil be a full 3" turbo back system, bigger IC and then another remap to suit. I'll get back to you with the td04's a/r when I find out. But it's pretty small (spools up very quick....so it's tiddler!)

I've ordered your book so will get reading up next week, pretty keen to go for this. I think it's the ideal solution for me vs upgrading my turbo

Thanks for the reply Trevor. Just slowly reading through the book now (good & informative!!!) and starting to get the bits & pieces together for the engine mods. Intercooler & injectors bought, next will be clutch & diff then finally decide on the turbo choice