Tuning propane on Sami

DuctTapeMafia · Oct 16, 2011

I am running a stock 1.3 and am geared down with 6.4.1's in the T-case and 4.88's at the axle. It goes killer in low range but it is killing me in high range and on the pavement. I can barely get up to 55 MPH on flat ground and if the wind isn't playing nice, I can't get over 40 MPH. I love the propane mileage and price but I need to get this thing moving. Does anyone have any tips or knowledge that can help me out? My kit is from Got Propane.

Bunk1 · Oct 16, 2011

Mess with your timing. Base timing is way higher than stock and you should be at max advance by 2000 rpms.

Do you have a mixture gague in your exh to see how rich/lean its running?

skinny_pedal · Oct 16, 2011

With 6.4 and 4.88's your not going to go faster that 55mph with that gearing.

DuctTapeMafia · Oct 17, 2011

skinny_pedal said:
With 6.4 and 4.88's your not going to go faster that 55mph with that gearing.

I can't even get into 5th. I also should have stated that it would hit 70 topped out when it was carbed. I am just lacking the power that I had before. I realize that propane costs me a percentage of horsepower but I should be able to shift out of first when pulling hills in town.

DuctTapeMafia · Oct 17, 2011

Bunk said:
Mess with your timing. Base timing is way higher than stock and you should be at max advance by 2000 rpms.

Do you have a mixture gague in your exh to see how rich/lean its running?

Thanks, I'll try the timing and no on the mixture gauge . I have messed with the mixture screw and found that I can make it run awesome for low RPM and it will suck on top end or vise-versa . I have heard tales of a part found on small Cessna and Piper aircraft called a Dial-A-Jet. This is basically a Mixture screw attached to a cable with a adjustment knob located on the control panel (or once I find one, a dashboard. ). Has anyone ever heard of this?

Bunk1 · Oct 17, 2011

DuctTapeMafia said:
Thanks, I'll try the timing and no on the mixture gauge . I have messed with the mixture screw and found that I can make it run awesome for low RPM and it will suck on top end or vise-versa . I have heard tales of a part found on small Cessna and Piper aircraft called a Dial-A-Jet. This is basically a Mixture screw attached to a cable with a adjustment knob located on the control panel (or once I find one, a dashboard. ). Has anyone ever heard of this?

Sounds cool, And i dreamed that idea for my rig at one point. I would be way more concerned about knowing that your mixture is good before being able to blindy adjust it. Having a gague will tell you immediately how your mixture is doing. It aint cheap(200 or so) but whats a engine cost?

mcbadwish · Oct 17, 2011

Have you checked for vaccum leaks?

ChrisStewart · Oct 18, 2011

Like Joe said, get a mixture gauge, and make sure your timing is correct. You don't lose power with propane, people think they do, but in reality it's just not tuned right. If it's a true Got Propane kit, call him and he will help you until it's running perfect.