NOS and LPG - Ford Forums - Mustang Forum, Ford Trucks, Ford Focus and Ford Cars

DansEdgli · 02-13-2003, 04:37

Is it possible to use nitrous and LPG together?

I was thinking the other day and if you are using a straight LPG turbo setup and the car backfires will the whole fuel system erupt? If not what stops it happening?

Also if a car has a cam and headwork, carby and manifold for a high horsepower N/A application then how would the car respond to having the same engine except for dished turbo friendly pistons?
This would occur if my bottom end was built and used before my turbo manifolds are completed.

Thanks
Dan

BLWNEB · 02-13-2003, 05:37

You can use nos on any car I believe, but if you got a kickass engine and driveline with turbo, straight gas you wouldnt need nos, john a mate of mine his XF pulls 10.8s on straight gas.

Rollin · 02-13-2003, 21:04

yeah the engine will still go hard if you have low compression pistons - not as hard as it otherwise would, but if you are definately going to turbo it then it is worth getting low compression pistons now, to save you putting them in when you get the turbo happening

mate your car is going to be a ROCKETSHIP when it is finished!!!

xced · 02-13-2003, 22:40

with the cam, its important that you dont have one with too much overlap (which some high performance NA cams can have!) on a turbo engine this just ends up with air and fuel being blown striaght out the other side :)

DansEdgli · 02-13-2003, 22:59

Thanks for the replies guys. I was actually going to buy a ghia for a whole stack of goodies to go into my car. I was going to take out the block and rebuild it to be strong enough for the turbo and then chuck it my car and work out the manifolds and other turbo afterwards so i can slowly piece this project together over the year on my big fat university income (HA!) and when i get to really work again next summer i can finish it off with the extra cash i have.

Does anyone know if Nitrous and LPG mix like normal fuel?
Also if the car backfires and the flames shoot through the exhaust side into the turbo what happens?

Thanks
Dan

xafalcon · 02-14-2003, 00:06

With NOS, the petrol is also used to cool the combustion chamber (latent heat of vapourisation to use a techo term). This effect is lost when a gaseous fuel is used, and you run the risk of engine meltdown or severe death rattles. If you are going to run NOS, use petrol as your supplimentry fuel eg run the engine on LPG and the NOS on high octane petrol.

Good luck
Tris

tonyk · 02-14-2003, 01:45

Hey Dan....

A motor which has an unburnt fuel explosion in the exhaust may damage the turbo vanes but I havent heard of too many doing it.

LPG mixes like any other fuel except for its basic expansion change (see below). LPG draws heat from the atmosphere (or anywhere else) to move from liquid to vapour. At no time does LPG create heat.
Nitrous cools the intake for no other reason than it is a liquid trying to get to a gaseous state at time of introduction again drawing massively on the environment for heat, thus cooling the area around it.

About nitrous...
Spark retard and overrich fuel mix is only safe way to use nitrous and ANY fuel.
You can use LPG and N2O BUT the issue is metering.
LPG expands 270 times during its change from liquid to gas. Its is very very diffcult to meter it down.
It can be done and heres how youd do it but you may have to be happy with a very overrich mixture or a lot more nitrous (hence HP) than you bargained for. Bear in mind this requires big investments in piston/rod/crank etc materials and you wont build any good LPG nitrous blown motor on a budget.

From an ease of install point its better to use petrol and nitrous cos all the data and kits are already out there off the shelf.
PS if you use LPG as a method of going thru DOT emissions the fuel kit will make your car defectable.

With LPG however.... its a different and difficult story.

As a starting point... If you start with a nitrous jet of 1.2mm you have the potential to add 100HP. Start with an LPG jet of the same and you flood the motor instantly. Work backwards until you get a "sweet" over rich mix. The issue is you end with an orifice for LPG that will probably freeze over because its that small.
If you persist though... Its really just trial an error and lots and lots and lots of plug reading. If you get alloy on the plugs your consuming piston material and you are too lean.
From what I've heard (I started down the gas nitrous road but it proves harder to do than I thought unless you only want 25hp. just run dry then) you can tell your on it right by the sound it makes and the "feel" of the kick.

Testing the mix should be done while stationary.
Run the motor up to 3000rpm.
Flick the switch... a lean mix will take off and break up quickly but you should probably never get there as you are starting rich (always rich)
A rich mix will just stall and flood.
A sweet mix will take off and you'll shit yourself and kill the motor.
It will "sound" perfect. It will rev out cleanly all the way.
Its a good idea to use a MSD with spark retard and rev limter if you can stretch to it.

One point to never ever forget is to retard your spark by 2-4 degrees at max for each 100hp you add or you will eat pistons.

There are a lot of nitrous tuning links on the net and the technique is just the same for LPG.

Sorry its a bit rambling Im working from memories that are a year and a half old.
Theres a guy in the UK who did kits for motor bikes with little more than a 9kg fire extiguisher each for the gas and "gas" and nitroous solenoids with 4mm orifices in each. He just made the kits for a laugh and they worked on bikes OK.
I cant remeber his name... something like "Burgermann".
Hes in a wheelchair after a bike accident from memory.
Great guy though.. answered all my email till I gave up on the idea.

Have a crack by all means but its not cheap if you do a shit job or a good job unfortunately.

tonyk · 02-14-2003, 02:13

I done some digging.
Dont worry about what I say

just read the "burgerman" site.

www.nitrous.info
www.burgerman.info for a bio. Hes bloody good.

If you are successful post the results. You have rekindled my interest!!

Rollin · 02-14-2003, 02:23

Quote:

With NOS, the petrol is also used to cool the combustion chamber (latent heat of vapourisation to use a techo term). This effect is lost when a gaseous fuel is used, and you run the risk of engine meltdown or severe death rattles. If you are going to run NOS, use petrol as your supplimentry fuel eg run the engine on LPG and the NOS on high octane petrol.

nitrous by itself will not make you car go faster - nitrous is nitrogen combined with ocygen, from memory its about 2/3 nitrogen and 1/3 oxygen. i think the normal % mix in the atmosphere is about 16% oxygen, so we add X amount of fuel to make it burn (i think with petrol about 12.5:1 air/fuel mix is best for power) if you increase the amount of oxygen going into the motor, you need to increase the amount of fuel going in so the ratio is that same (12.5:1) or thereabouts, as tonyk said, richer is better when you talk nitrous.

if you dont add extra fuel you get no more power but your engine dies.

though if you are already going the turbo LPG route then NOS will not be needed - boost on a LPG car is legal, safer (for engine and driver!!) and less expensive.

just build a 'full sik' motor thats tough as nails, and instead of adding NOS just add another 5psi boost - effect should be about the same, but you stand less chance of it all going very horribly wrong.