I am fairly knew to nitro trucks but I have been racing boats for a
long time and I was wondering why nobody uses more than
20-25% nitro in thier cars or trucks ?

In my boats I run as high as 60% nitro with no problems and I have been using 50% in my savage with no problems either.
I ran 10% when I first got the truck until it was gone and I didn't feel like buying extra fuel for the truck so I started using my boat fuel.
I have zero problems with temperature (210) the truck is easy
to dial in and the fuel has plenty of oil .
I have inspected the combustion chamber and have zero detination and the plug is perfect not to mention the performance is much better as well.

So why only 20-25% ?
Is there any rule for racing that limits nitro?.

Thanks T Kish

Check your deck hieght in the boat engines and I bet that its 3-4 tousands more than your car engine. Thats why the engine designers give you the extra shims, to run 30% nitro. Most conrods in car engines cant take the abuse of 40% nitro for long.

I agree with you on the con rod it does look kinda week in the savage motor, actually the quality is pretty low on this motor compared to the marine engine we use and that will be were it fails.

The Nova Rossi line for cars is very high quality rod included and they also make the best .21 size marine engine in the world.
Remember this was a question of high nitro use in general and I know for a fact that the Nova Rossi line of car engines love high nitro.

As for head clearance I make my own heads for my boats and I run them as tight as possible until I see sighns of detination then I will raise it a couple thousands.
The Savage is stock and I never bothered to measure it because there was no sghn of detonation either and the truck is just for fun.