Not that I'm in the market for it (yet ;) ), but I'm looking for info.

I know that some Viper guys have been using nitrous/propane on their cars with good results. It seems that it is good for more torque than HP, but still provides good gains.

Basically, the Propane replaces the gas in a wet shot.

The benefits I can see with this are:
1. there is no risk of fuel falling out of suspension (puddling)
2. there is no extra strain/demand on fuel system
3. there is a high resistance to detonation (~110-140 octane from what i've been told)
4. propane is cheap and readily availibility.

But I cant find much info on this so I'd imagine tuning would be difficult... and if anything were to happen while racing or otherwise, you would have a propane tank in the car (BOOM!).

Here's a link to a company that offers a kit for LS1 Vettes. http://www.btrviper.com/vetteproducts.php

Do any of you guys have any info and/or opinions on this?

Thats pretty nice. I like the idea that you dont need to worry about a fuel pump only bottle pressure. System looks like it has alot of potential. If you see one for carb'd applications post it I'd love to try it. If you use it properly I don't think there is much to worry about. A nitro tank is compressed and there is lots of force in there but what scares me is the flammability. I'd probably wear a flame retardent suit at the track, and take care at where the propoane is mounted. I'd face the top of the bottle towards the rear of the car in case of an explosion. Good Luck
Dane

I have no experience with what you are trying to do... but maybe this will be some info:

LPG is quite cold, about -40° if I recall, and can cause freeze 'burns'. Maybe that is good from a fuel charge density perspective, not sure.

LPG has a pretty low flamibility range, I think it is about 2.5 - 9% propane vapor. Yes it can ignite and be dangerous, but it would be less so than gas I think....

Propane in a gas form is heavier than air.

i have used propane injection over gas and diesel both in the past. worked great! the theory behind the propane injection is that introduces or is able to care more oxygen into the cylinders than gas alone causing a more complete burn. the company i purchased mine from explained it in this manner. during normal combustion you may have a 75 % burn of fuel, the unburned fuel results as exhaust along with the burned fuel. with the propane the burn becomes more complete say to around 95 %. your horse power may not increase by a large amount but your torgue will due to the more complete burn. the other benefit is increased fuel mileage and reduced engine oil contamination. in my diesel after running the propane injection for about 1500 miles i changed the oil, after that the oil remained clean just as in a gas engine. i currently have a system that i am going to install on a 1 ton van

Ron, that is another advantage I forgot to mention. When pressurized the propane is a liquid. I think LP is -43*. This can really help cool the intake charge.

From what I have seen, the Viper guys are running 1050-1100psi N20, and around 200psi LP, and getting very good results.

BTR (http://www.btrviper.com/nitrous.html) (the big company for this right now) advertises a few kits (for Vipers). One of them is rated to give 175hp and 220ft/lbs with a single stage N20/Propane system.
If you want to run N20/Gas/Propane, then they guarantee 150+hp and 350+ft/lbs.

Also, for anyone interested, it looks like, at least for the N20/gas/LP system, the ideal A/F Ratio is 11:1


- Matt

Matt, I'm building a 454 .060 over engine to run on propane only and have found it very hard to find info on performance minded engines. Most will tell you that you will loose some HP over gas and I really coundn't see how. As with any engine combo you need to match the parts and if you use propane the parts need to be tailored for propane. I talked to a local engine builder that builds alot of propane engines alot of them he turbocharges. Basically he told me a propane engine was built very similar to a alcohol engine. Needs lots of compression (mine is around 13.5:1) heads with huge ports, intake with huge ports, big headers, have at least 1500 to 2000 cfm mixers to feed it, you cannot over carburate a propane engine it will only use what propane the engine can take in. I haven't got my engine completed yet but I think I will be very happy with the results. A little off subject but just something else to consider.

Yeah, -43 or -44, I was going by memory from when I got my propane pumping license as a teenager working at the local gas station... It sure is cold, even as it vapourizes the instant it hits atmosphere, it still can leave a nasty freeze burn... should cool the intake charge nicely I guess :D

Originally posted by 70Chevellenurhlp:
Matt, I'm building a 454 .060 over engine to run on propane only and have found it very hard to find info on performance minded engines. Most will tell you that you will loose some HP over gas and I really coundn't see how. As with any engine combo you need to match the parts and if you use propane the parts need to be tailored for propane. I talked to a local engine builder that builds alot of propane engines alot of them he turbocharges. Basically he told me a propane engine was built very similar to a alcohol engine. Needs lots of compression (mine is around 13.5:1) heads with huge ports, intake with huge ports, big headers, have at least 1500 to 2000 cfm mixers to feed it, you cannot over carburate a propane engine it will only use what propane the engine can take in. I haven't got my engine completed yet but I think I will be very happy with the results. A little off subject but just something else to consider. Wow - that sounds like a cool project - please post a follow up when you are done!
Ron

I think this could be the answer to running high compression on the street.