Nitro Questions

[masracingtd1167]

I am seriously thinking about the change over to nitro with my car . I plan on doing it this winter but I have a lot of questions . I know I have to drop my compression to ? How about valves I use titanium valves are they ok or should I use something else What would be a good time to call you I have too many questions to type . Thank's Bill

[Spud Miller]

 Hi Bill,

 It all depends on how much nitro you want to run...which depends on how fast you want to go...which depends on what equipment you have already.

 The best, most efficient plan for working with me these days is to complete one of my questionnaires:

http://fuelinjectionent.com/questionnaires.htm

 ...email it in along with your desired goals for performance. I can help you figure out how much you'll need to run to get there and then what'll need to change and how much to change it to do it safely. I'll shoot you back an email with a couple of proposals for an appointment on the phone so we don't play phone tag (I'm always on the phone already it seems).

 Then I'm up to speed with your stuff when we do talk, and we keep phone time to a minimum.

 For light loads, 12-13:1 works ok if the cam is big (duration/overlap). Titanium valves are just fine.

 I hope to work with you soon!

[ricardo1967]

Spud beat me... anyway, I was going to refer to the very informative "Spud's Nitro Notes" at http://fuelinjectionent.com/.

[longm1958]

Spud,
What exactly is a light load? 20-30%  ? Or more?  I have been told that 20-30% really isn't gonna do too much for performance. Is this correct?

[Spud Miller]

 Anything under 35% is light in my opinion...not a whole lot needs to be done to a methanol car to run that.

 You'll notice a big difference. The only folks who don't are the ones who richen it up so much, it cancels out the benefit of the nitro.

 

[hotrod316]

If you run 35% do you need to back it off or down (turn the motor over by hand the wrong way) the motor after a run and second do you need to back it off or down the motor if it does not start on the first try? sorry I know this does not make any sence! to me too
thanks for your time
steve m.

[masracingtd1167]

Spud I am going to fill out one of your Questioner forms this week and send it to you . I plan on new pistons this winter so I can make the compression any thing you wish.   

[Spud Miller]

If you run 35% do you need to back it off or down (turn the motor over by hand the wrong way) the motor after a run and second do you need to back it off or down the motor if it does not start on the first try? sorry I know this does not make any sence! to me too
thanks for your time
steve m.

Regardless of percentage, avoid having anything leftover in the cylinders when you fire. The higher the percentage, the more risk of an explosion but even lower percentages need to be treated with respect.

Spinning a wedge head type motor backwards does nothing...just remove the plugs and windmill the motor to spit it out. You can also squirt methanol in the plug holes to dilute anything in there and then spin that out too. A must at high percentages.

Windmilling a hemi type motor with the plugs out doesn't do much to remove fuel. Backing it down (the plugs are out) is the way to do it.

Starting up on another fuel and changing over is the safest way to fire up, but isn't practical at lower percentages. In my opinion, the most practical way to start with lower percentages is to begin with a motor that's void of left over fuel, then prime with gas (pump or squirt bottle) so that it fires right up. If you're cranking and cranking and it isn't firing, abort, dry it out, figure it out.

Drying a system out is pretty quick and easy...just remove the fuel supply hose to the barrel valve, blow everything into the motor (open and close the throttle a few times while blowing) then spin the motor (windmill it or back it down) to get the fuel out. Rinse and repeat if you like.

Another risk besides starting is a crew guy putting a wrench on the crankshaft to check valves or something and having something go off. We remove the spark plugs at the top end of the track and they stay out of the motor until we're ready to fire or head to the lanes. The plugs are like the "fuse" for the bomb...as long as they're out, bad things can't happen. Only put them in when the motor is dry and everything is ready to go, wrenches off the crank, mag is grounded, etc.

[hotrod316]

THANK YOU VERY MUCH SPUD that is what we did  last night just wanted to be sure and not hurt the motor or my driver! full report is comimg. again thank you for your time
steve morgan
PS I NEED MORE NITRO $$$$$$$$$$$$$$$$$$$$$$

[225digger]

dumb question , what is windmilling and what is backing down ?    i have an idea but not so sure . windmilling is using the electric starter to clean out the cyls . and backing down is just using a breaker bar on the blower ?

[Spud Miller]

 
 Yup.

 Windmilling = Spinning the motor over with the plugs out

 Backing down = Spinning the motor over backwards by hand

[hotrod316]

thanks Spud here the pudding, 2 tens

[dreracecar]

What happens when you dont back it down and try to light it.  Its still good to do on a wedge style engine on alc as by turning over the engine in reverse it will clear the cyl of most of the fuel "IF there is for some reason more fuel than the combustion chamber can hold and dont wind up bending the rods