Hi Guys. Just putting a question out there.
For as long as i care to remember i have wanted to add nitrous to my car. Never actually got round to doing it.
What are the dangers/pitfalls if any in adding nitrous to the xkr? I would have thought if the boost is not too high then these motors should be ok.
What are your thoughts.......cheers

 

The use of nitrous requires the ignition map to be retarded in order to prevent pre-ignition (detonation) from the resulting increase in combustion chamber pressures which would break the piston ringlands otherwise. We have no ability to change the ECU's ignition mapping to compensate. Some tuners offer a re-map of the ECU to allow for a slight increase in pressure from a supercharger pulley swap, but none for nitous that I'm aware of. The pulley and ECU may provide all the extra power you require.

Bruce

 

Here dyno chart of stock 4.0 XKR with and without NOS: http://www.powerhouseautomotive.co.u...Dyno-Chart.jpg . The 100HP kit made car 1.0 sec faster on 1/4mile.

 

I know the pully change would be the more obvious way to go i suppose. If nitrous is possible i wounder how the cost to power gains compare?

 

I'm quite certain as you research it more that you will find it not possible, economical or advisable. It's also likely that the ECU and/or TCU would engage anti-destruction measures to reduce power as is the case with the pulley and ECU that we've found with those doing it on the 5L recently. The cost of a new motor or tranny would also affect your cost/hp calculations!

On applications where nitrous can be installed and tuned properly it does offer a lot of cheap power, but only for the moment that you're pushing the button, and there are endless downsides and risks to using nitrous. Kids think it's a blast, but it's nowhere near as simple as many think...and not at all as portrayed in the Fast and Furious movies

Bruce

 

Recommend that you do some research on the subject, and not rely heavily on internet advice. Can recommend Joe Pettit's book "How to Install and Use Nitrous Oxide" published by SA Design.

I suspect there are several nitrous installers/tuners in your area to consult.

My local guru/installer has recommended starting with a low level application, and living with a moderate power increase.

 

Nitrous injection actually cools the intake charge as the compressed nitrous oxide from the bottle tends to be injected at near freezing temps as the gas suddenly expands as it leaves the compressed bottle. Thus, it is actually rather easy on the engine for the amount of extra power you gain.

The injected nitrous alone would gravely lean-out the fuel-air mixture. Thus, the setup requires additional gasoline to be injected when the nitrous is being applied. While possible to reprogram the engine fuel computer to add a specific volume of extra fuel only when the nitrous is being applied, it is likely beyond the ability of a home mechanic. Most of the ready-made, car-specific kits would have solenoid operated nitrous, as well as extra fuel injectors so when you press the button to activate the system, it picks up both solenoids and injects the nitrous gas and the extra gasoline into the intake runners.

Needless to say that the main risk is if the fuel solenoid fails to operate, the mixture will go instantly lean and the engine would be destroyed before you would even know what happened. Small chance for such failure but, you asked for the pitfalls.

It is a cheap and easy way to get a lot of horsepower but, do note that a 10lbs bottle only lasts for a few seconds worth of applications. Needless to say, you have to find ways to mount the bottle, plumb the gas into the engine intakes and install the extra fuel arrangement. Not a HUGE undertaking but, takes some time.

Some years ago during Indy qualifying, Mario Andretti turned in the fastest qualifying lap. Radar guns told the observers that he exited the corners at pretty much the same speed as everyone else but, for some reason, he accelerated in a single lap faster than other people with the same engine and chassis. They tore his engine to pieces during the mandatory tech inspection and found that he actually had a tiny Nitrous bottle machined into the engine block. It was small, only enough for maybe a second worth of application but, gave him just enough extra power to get the pole position.

Albert

 

You can get as much power from nitrous injection as you dare. 100 extra HP is a piece of cake. Some people will push for 300+HP gain. Years ago I used a 100 HP kit on my street car and it worked flawlessly and the engine held up far beyond 100K miles after a sold it. Mind you, I did not use it very often, only when challenged by some other hot-rod.

Pulley will give you generally 2 psi extra boost and the generally used figures in turbo/supercharging is 7-15 HP/1 psi extra boost.

Albert

 

Thanks for all the info guys. I have been doing more research. I think with the extra work/cost involved and possible explosion of my xkr may not be a wise thing to do. I remember top gear in the uk put a nitrous kit on a xjs. That thing flew!! It didn't seem a hard thing to do. May be normal aspirated engines are better suited to nitrous?
I am still really keen on fitting a nitrous kit. But maybe i will do it to a car that doesn't cost the amount the xkr does. So now the hunt for a suitable car begins.