Nitro %

[Greg Bonahoom]

Has anyone ever compared the difference in speed between say 50% vs 60% nitro with the same setup/oil package on a 21 rigger? Is it worth running 70%? Just curious what others have found.

 

[Marty Davis]

Greg:

That would be a great test on our dyno. I will do that next time we test.

I personally have always run 65% in my 20 boat and about a year ago switched to 60%. I didn't see any reduction in performance BUT I did find that I reduced my detonation a ton.

I will stick with the 60%.

 

[John Knight]

About 6 years ago when the price of nitro went up due to short supplies, a fellow club member and I did a test. He was using 50% and we tried 25% for a test. Same oil %. Using a radar gun, and a 20 hydro, he lost about 2..5-3 mph dropping the nitro in half. Not much when dropping the nitro in half. Did a test between 50% and 60%, it was less than 1 mph. This was heat racing setup only and not SAW. The lower nitro % will be more forgiving on the needle and as Marty noted, less potential detonation. Is the high nitro % concept overrated? Yep IMHO.

 

[Marty Davis]

About 6 years ago when the price of nitro went up due to short supplies, a fellow club member and I did a test. He was using 50% and we tried 25% for a test. Same oil %. Using a radar gun, and a 20 hydro, he lost about 2..5-3 mph dropping the nitro in half. Not much when dropping the nitro in half. Did a test between 50% and 60%, it was less than 1 mph. This was heat racing setup only and not SAW. The lower nitro % will be more forgiving on the needle and as Marty noted, less potential detonation. Is the high nitro % concept overrated? Yep IMHO.

You are leaving out something important. I want to be able to swing a lot of prop to go fast. With 25% nitro you will lose a TON of low end launchability and not be able to turn the kind of prop that I want to use.

 

[NOVALTD]

When I tested a 21 Road Runner UL and changed fuels from 50 to 60% nitro within 5 min so air and water conditions were the same ,we saw 2-3mph here in south florida were we have higher humidity

then normal. Yes detonation did occurred ,but low end torque was far less at 50% then 60%. You can have all the rpm and speed in the world ,but without torque for acceleration you will be hurting in overall performance.-- Dan Mccormick-namba 221

 

[Andy Brown]

Was run my 45 SG one day in 1997. Was running consistently 92 mph on 60% using a cupped V955 and an Mc #9 plug. No turnfin.

Switched to 70% and it would not launch.

Switched the plug to Mc #59. Launched well but speed was only 89 mph.

Switched prop to 2160 cupped 5.8". Next run was 100 mph.

The moral of the story: More nitro IS more power, but other parameters in the system must match the amount of nitro.

On the other hand, Jason Brown raced his K-90 powered SGX at the 2013 Fall Nats on ZERO % nitro and was competitive. Certainly not the fastest but fast enough to win heats with good driving skills.

 

[Chris Wood]

the key to it all if it is 10% or 70 is maxing out the prop pipe combo. you can run fast on lower it just take more train of though on prop work

i run 65 & 70 %. that is what works. i tried lower yrs ago and it wasn't for me. again for what I DO.

but like andy said.. nitro is power. just a matter of putting it to use.

 

[Greg Bonahoom]

Thanks all for the great responses.