Let's say you had a stack injected BBC on alcohol that's 13.1 compression. Let's also say your track was closing for good and you had a race at the end of the year where all bets were off. How much nitro could a guy safely run for one pass and not kill the motor. Asking for a friend.....

Read thoroughly.....
Nitro Intro
Takes a lot of ignition lead to get the slow burning nitro to make good power.
Good luck!
BW

There are a lot of variables but from my experience if it is in fact 13 to 1 you could probably get away with 20% and as long as it is under 30% you do not need to fatten it up or change timing. I would go into burnout a little cooler than normal and WATCH YOUR WATER TEMP because it builds heat faster and you do not want it to get too hot (Detonate). Also add about one quart of Toluene to one gallon of Nitro to help prevent detonation. Even 3% of Nitro will burn your eyes and choke you if the wind is blowing on you.

Use Hygrometers and get the mix perfect. Even small percent like 2 or 5% will make a difference in performance.

Go to FIE and read spuds nitro notes. 30 to 35% before making lot of changes. You will have lot higher stall on converter since tq goes up about same percentage at the nitro, well according to Spuds tq calculators.Accoring ti calculator and conversation with FTI my combo will be aboput 700 rpm higher with 20 to 25% load. As for smell at 20% I can smell it but is eye burning strong.now this is from guy who use to inhale deep when they fired TF cars. Use to being key word not now days.

With 13:1 your about same as A/Fuel cars run,little higher. I would sart at about 10 to 15%.little rich( if fell need which its not) and tune from there.You will probably end up leaner than alky set up when final. Again Read spuds nitro notes a lot of good info and its free.
Importance of system maintenance is dbl,but still just basic. Flush system at end of day,spay some lube in it for o-rings and should be good. Changing o-rings to ethylene propylene is not bad idea either. Works with alky and nitro just does not like gas.

If you do math a 20% mixture is cheaper than a lot of the upper end racing gas and a 20% boost(roughly) it TQ to boot. Oh yea and sounds cool as he11 .

Caution use of this product can be addictive and cause bankruptcy. Disclaimer done.

I ran some test on the dyno and at 13 to 1, 30% is a little much,you might get into some detonation, although if your "friend" is at altitude he might get away with it. I would stick to 20% to be safe and you will notice the difference.
also because nitro is so much heavier them methanol, you can leave the jetting the same until 30%.

joe

This message has been edited. Last edited by: sr4440,

PS.. Dont forget to post your results

I ran something around 5% for one pass, once upon a time, trying to make a Quick 16. I thought nobody would notice, but the exhaust smelled about the same as 90%!

I can't remember what the gain was, but it was surprising although we fell a few thousandths short of qualifying.

Thanks gents! My friend just figures since its the last race ever here, and he has an FED, that it would be fun to say he did it once. We should be around 5000' DA if the weather is right and the car should be in the 8.20's on alky. Would be delighted to put a lowly 468' with iron heads into the 8.0's....

I'll keep you posted on "his" decision and subsequent results. Have to be careful though. We have the ET Finals the next week in Vegas and can't hurt the car before then. LOL

Well as “his other friend” when he blows it up I will post pictures of the carnage. Some peoples kids these days – Geezs!

I ran 10% on a few occasions a couple of years ago with a Rons Terminator with mixed results, only picked up maybe a tenth at best in the 1/8th and a couple MPH. Warming up in the lanes would piss off everyone around you for sure lol

I think if your compression is 13 to 1 or less and you keep it 20% or lower it will be okay.
Remember to put some Toluene in there.
Should pick up and run the 8.00 easy. More compression than 13 or more than 20% it will start eating parts and spitting out pieces.

Wallace,
A little bit of sunshine.
Unless that engine has been blueprinted and actually measured out at 13:1 it may be only 12:1 or less if it is based on catalog specs.

If the latter you have a little extra wiggle room for %.

But yeah, 20% on a BB will likely get that 8.0 or better.

You might want to start at about 10 percent and take a good look at your plugs each run !Work your way up from there ! My compression is over 14.0 but I run a long duration cam ! With straight methanol my car runs mid 7 thirty's on M5 7.28 best and with 15 percent a 7.11 best ! Yes it dose work just don't get too greedy !

quote:

Originally posted by Wallace Cleaver:
Let's say you had a stack injected BBC on alcohol that's 13.1 compression. Let's also say your track was closing for good and you had a race at the end of the year where all bets were off. How much nitro could a guy safely run for one pass and not kill the motor. Asking for a friend.....

Bringing this back up to mention a few things.
How much Nitro could you run with out hurting motor? Possibly as much as 20% if you are not using a 2 Step. Probably about 5% if you are using a 2 step. The 2 step seems to cause it to Detonate and eat up expensive parts. One other thing to keep an eye on is engine heat, gets hot detonates easier. My cooling system is set up for alcohol and rather small. works great with alcohol but struggles with Nitro.

Your mileage may vary.

Small percentages of Nitro work well with Mechanical injection not so much with carb because mechanical injection is positive displacement and a carb works off berneuilli (SP) effect which is effected by heavier fuel. A carb may work with Nitro with right jetting changes?

Some say you can run up to 30-33% because the Nitro is heavier. On paper that may be true as far as right mixture but that does not mean your pistons and rings can handle it. Ring packages now are thin and up close to the top. That may not be best for Nitro. Certainly do not think that just because on paper that you can go to 30% on your motor. My experience says you can hurt parts at much lower percentages.

Also higher compression ratios make any tuning window smaller and damages more extreme with all fuels.

Similar with timing. Nitro burns slower so you can run lots more timing. Not so fast there. Depends on several things like compression, heat in the motor, Nitro percentage and other variables.

I am going to do some DYNO testing with Nitro soon to try to learn more.

Nitro burns slow and hard to keep lit. Better add timing maybe tighten plug gap. If the timing is left low (normal) it will have excessive aroma and egt. Still burning in the exhaust.

Edit: yeah everything is posted above. I'm slo

This message has been edited. Last edited by: bry-war,

quote:

Originally posted by bill masiello:
You might want to start at about 10 percent and take a good look at your plugs each run !Work your way up from there ! My compression is over 14.0 but I run a long duration cam ! With straight methanol my car runs mid 7 thirty's on M5 7.28 best and with 15 percent a 7.11 best ! Yes it dose work just don't get too greedy !

Bill, when you ran 10% and 15% were you able to use the 2 Step?

At 10% on my motor it did not like on the 2 Step at all.

ran 20% for a while in my rig. 13.86:1. Had to pull some timing (33 to 28) and it picked up big time. Meth injected. I kept putting more and more timing in it and it never picked up anything to speak of (a few hundredths). Tried backing it down and it came alive. Also took a little fuel out of it (80 to 85 pill). Stuff's expensive. and everyone's stuff is different, so it'll take a little tuning to find what yours wants. Everyone will know, it stinks. The fumes can paralyze your breathing if you get enough of it, and I've had this happen and it's scary as heck. SO be careful with it.


if you have a dual fuel system it helps with starting as well. Not a great idea to start on nitro mix with a hot engine and high compression.

As long as you are running small load like 25 to 30 % starting straight from tank is no issue, Now if you run 80% load or so you better start off alcohol then switching to notro is running good amount of compression.

quote:

Originally posted by M802138:
ran 20% for a while in my rig. 13.86:1. Had to pull some timing (33 to 28) and it picked up big time. Meth injected. I kept putting more and more timing in it and it never picked up anything to speak of (a few hundredths). Tried backing it down and it came alive. Also took a little fuel out of it (80 to 85 pill). Stuff's expensive. and everyone's stuff is different, so it'll take a little tuning to find what yours wants. Everyone will know, it stinks. The fumes can paralyze your breathing if you get enough of it, and I've had this happen and it's scary as heck. SO be careful with it.


if you have a dual fuel system it helps with starting as well. Not a great idea to start on nitro mix with a hot engine and high compression.

Were you able to use Two Step? Mine detonated bad at 10% while on the Two Step. Appears I could run much more on dyno or on the track with out Two Step.

you guys using two steps with nitro get a thumbs up for guts.

Guys something I found out that might help. The valve pockets can be a issue, With injected motors not blown. Seems the nitro(fuel) can puddle and then just go off when compressed. This may or may not be problem for you guys that are having detonation issue. I can really see this as problem with 2 step. Just one of those thing you find out after the fact.