Nitro Question.....

[mphmotorsports]

Going to run 30% Nitro later in the year..... Once I fine tune my Hilborn Injection Stack set up (Changing from 16as to 14as nozzles and setting up High Speed Bypass), do I need to put more fuel to the motor when I put 30% Nitro mix in ( with 14 as nozzles, I'm planning to start out with a 75 main jet) and what about the timing (currntly running 38 degrees) and what about the high speed???
Thanks for the help!!!!! 

[hotrod316]

we when 33% last year and changed nothing = 2ths FASTER.
 thanks to the man grandpa Coker he may have saved our little motor
be careful using  the 2 step, dropping cyc at the start.
our first pass is on here somewhere or u tube sm racing first pass on nitro
IT'S A BLAST
MAN SUMMER COME ON i NEED A FIX
ASK MY DRIVE AMANDA ABOUT BURNING THE PAINT ON THE CAR WITH THE GOOD STUFF

[mphmotorsports]

Was thinking about the 2-step also Hotrod 316.... might have to lower the launch rpm a little to... will look for your first pass and Thanks for the info....

[JrFuel Hayden]

I assume your change to the smaller 14 nozzles is for running alky. I would think running 30% you would need more fuel/ bigger nozzles.
I would call Don Enriquez at Hilborn, he can be a big help on what you are trying to do. Also Spud can help.

Our all iron SBC NHRA Heritage Jr Fueler, burning only alky, running raised runner 23° iron heads currently using 14 nozzles, with a 1/2 Hilborn pump.  The main jet I run is mostly .76, and a .90 jet in the high speed, running 120 to 126 lb of fuel pressure, 2.36 to 2.40 fuel flow, depending on weather conditions, at 29-31° of MSD mag timing. Now I know non-raised runner 23° heads run more timing, like 36-38°.  BTW we, Hammer-Hansen-Hook, won the 2013 March Meet running that tune-up, running 7.02-7.04 @ 187-188 mph.
It looks like you are running alum heads and the timing may be different than iron heads. Just take a good look at the plugs looking for signs of detenation. Black or white speckles on the plugs, if you see that, back down on the timing or add more fuel pressure, or both.

To further confuse you, when I raced my 98% nitro high gear real Jr Fuel car in the mid to late 60's I ran 55° of timing with another 20° of advance in the Vertex, and a 110 Enderle pump [ a Top Fuel pump, at that time] . Our tune-up at that time was far-out, but I did run 192 mph in 1963, with an all iron 301 SBC , on 9" M&H's. Car weighted 980 lbs, no driver.

Good luck with your project.
Jon Hansen, Hayden Wheels, 800-624-3803

[hotrod316]

I went to FUELINJECTIONENT.COM site and use his tune up section helped a lot,
we also drop down the rpm by 400 on are last pass at 33%  no time slip
but the recorder said it should have help
it does make it smell GOOOOOOOOOOOOOOOD
p.s.I think spud wrote about this for us, see if i can found it
   

[mphmotorsports]

Hey Jon.... do my front wheels look familiar? I bought them from you a coulpe of years ago and they are fantastic!!!!! Thanks for the info. I currently run a 0 pump so my pressure might not be as high as yours on alcohol. What was your best time with that alcohol set up? I think I'll be in the ballpark starting off with my set for pure alcohol. High speed has a 94 pill and will crack open at 65 psi. Does that pressure sound okay? Let me know.   

[JrFuel Hayden]

Our best ET was 6.99, and best speed was 189 mph with the combo listed. ie; 14 nozzles, 1/2 pump, 76 main, 125 lbs pressure.
Your Hi-Speed opening at 65 may be high [ ie fat] with the 16 nozzles. The 0 pump might be too small , that's why I said call Don at Hilborn, he runs a low pressure set-up. The quickest-fastest non-raised runner iron SBC alky Jr Fueler in the world is the McKray-Enriquez-Algire 406 ci , best ET that I remember is 7.14, with a -1 pump, .125 main jet, open hi-speed jet, opening at 49lbs with 16 nozzles. The hi-speed is open at the hit, keep in mind the hi-speed is a pressure regulator in this application. Blown nitro, a different story.

Jon Hansen, Jr Fuel Dragster Association.com

[JrFuel Hayden]

I mis-Spoke, an Oops from a guy that builds Spoke wheels, McKray runs size 18 nozzles in their combo, not 16's
Of course there are other parts of a race cars that make for a good combination; gears, converter, wheel sizes, shift points, launch rpm.
Let the motor work in the rpm range it wants to, that's the trick, listening to your motor, as to what it wants.

I'm real glad you like your wheels.

Jon

[Spud Miller]

Going to run 30% Nitro later in the year..... Once I fine tune my Hilborn Injection Stack set up (Changing from 16as to 14as nozzles and setting up High Speed Bypass), do I need to put more fuel to the motor when I put 30% Nitro mix in ( with 14 as nozzles, I'm planning to start out with a 75 main jet) and what about the timing (currntly running 38 degrees) and what about the high speed???
Thanks for the help!!!!!

You don't need to change anything for 30% from a properly tuned methanol setup, but the fuel has a higher specific gravity, so the pressure will be higher. Assuming you're not already over 100 PSI or so at the finish line, that won't be an issue. But, for that reason, I would NOT run a high-speed lean out to start with on nitro. It generally isn't a big gain anyway. Once you've made some laps without the HS, then give it a try. The opening pressure will change from what it was with methanol - it'll be higher.

You can sign up for my free tuneup calculator here:
http://fuelinjectionent.com/register.htm

Once you've been accepted, you can login here to use the naturally aspirated version:
http://fuelinjectionent.com/members/unblown.htm

Here's the supercharged version:
http://fuelinjectionent.com/members/blown.htm

If you have an accurate flow tag, you'll get a pretty accurate pressure at 8000. Pressure is proportional to RPM. Getting a high-speed opening pressure from that at whatever RPM you want is pretty easy.

The calculators let you play around with various pumps, nozzles, percentages, pump drive combinations, weather conditions, etc.

Pump size doesn't change your pressure...give this a read for further explanation:
http://fuelinjectionent.com/bigpumpmyth.htm

Spud

[mphmotorsports]

Thanks Spud... I'm already setup as a user on your website....  I agreee that I need to get the alky setup right first before starting to add the juice. Does this setup for alky sound close. 356 cu in small block, 0 pump flowing 3.50 gpm@ 4000 rpm , 14as X 3-1/2" long, 75 main pill, high speed set @ 65psi and a 94 pill. Let me know!!!!!!!