Alternative fuel (cng, lpg)

joyfulchap · #1 (**permalink**) 03-04-2004, 11:16 PM

Considering the difficulty in registering a cobra replica in California, I am looking at the possibility of building it as an alt fuel vehicle (probably CNG). Has anyone had a good experience registering a CNG cobra?
Is this a good way around the hassle of getting one of the 500 permits for the year? I am curious if a CNG vehicle is exempt from the specially constructed vehicle requirements?

Thanks for your replies,

patrick &B-{>

Mr.Fixit · #2 (**permalink**) 03-05-2004, 11:47 AM

Where you gonna mount the CNG tank?
Got Stellite valve seats?
If I had to go alternative fuel, it would be alcohol.
Don't know anything about alternative fuels exempting your registration issues.

mtml427 · #3 (**permalink**) 05-16-2010, 03:24 PM

I have done quite a bit of investigation into the idea of using CNG. CARB has a great deal they would share as well. PG&E or any of the other gas providers may give you some insight as well.

kitcarbp · #4 (**permalink**) 05-18-2010, 11:38 AM

Have no idea about the reg issues in CA but in todays world, you want to go E85 since its readily available (in relative terms). The lower energy density for CNG will just take just take up too much room in tanks in my opinion and the geometry for standard CNG tanks are fixed (cylinders). It just depends how many cng cylinders you can safely mount in the trunk and what range you end up with, you need to calculate this based on your available space for tanks. If you are custom designing a cobra chassis and body for CNG tank fitment thats a different story, and can be integrated nicely Im sure.

E85 would be my first choice and it will not cost you more to build a E85 fuel system compared to gasoline if you're starting from a clean sheet design approach. Even to retrofit from gasoline to E85 is not to much $. I think you can buy E85 carbs (Edelbrock ???) in the aftermarket now. I have not priced it lately, but CNG hardware would add more cost compared to a E85 fuel Carb system. You could go FI for even more money if you want.
I would mount as big of a fuel tank or fuel cell as you can fit for E85, you can custom design a stainless steel tank to fit in your trunk (32 gallon E85 capacity comes to mind) if chassis is strong enough to handle it. If you want same range on E85 as gasoline to account for the lower energy density of E85 compared to 100% gasoline, you'll want the biggest E85 tank you can fit. My 2 cents.

Paul F · #5 (**permalink**) 05-18-2010, 01:49 PM

Registration in California is easy. Get one of the 500 numbers. It's painless and it's free. I've not heard anyone say they are gone this year. But even if they are, they have not been running out on January 2, so you should have one by then.

Wbulk · #6 (**permalink**) 05-18-2010, 05:27 PM

I have also thought about CNG. It's less than a dollar a gallon here in Utah, but you lose about 25% in mileage. Power will be down some to. Two cylinders could go where the tank would usually go. One of the draw backs of CNG is real cold weather starts, but on a Cobra you most likely would not be driving when it's really cold. The EPA does have some tight controls on conversions of newer vehicles. Those are pretty expensive, around 10K. I am not sure what the rules are on replicas. I think I will wait until we run out of gas.

Wbulk · #7 (**permalink**) 05-18-2010, 05:29 PM

Just saw this was a really old post. How did this get going again?

mtml427 · #8 (**permalink**) 05-31-2010, 07:56 AM

Quote:

Originally Posted by Wbulk

Just saw this was a really old post. How did this get going again?

You are correct. I didn't notice the date when I responded. The thread was listed at the top of the discussion board threads. Old but still something that may be worth considering.