Question: Going from 20% to 30%

[Sh1nn3r]

Quick question im getting a p5 that has been ran and broken in with 20% fuel, is it ok to switch to 30%. I know that i will have to enrichen it a bit and do some minor adjustments but would there be any reason that i shouldnt do this?

[Tex]

yes you can switch no problem. Don't even mess with the needles or anything just fill the tank with 30% and go. If it needs to be retuned do it at that time, don't try to guess before hand.

[DAVEC-NITRO-RS4]

Same glow plug?

[Sh1nn3r]

Yes, a mc8

[DAVEC-NITRO-RS4]

I was asking if you need a colder plug with higher % fuel. But with it still being cold out (even indoors!) will the hotter plug still be the best choice?

Tuning with glow plugs is a mystery to me.

[Sh1nn3r]

Naa, it's all expierence

[Czech-it-Out Graphics]

U dont need to change ur settings or plug, just add a .006-.01 copper shim

[DAVEC-NITRO-RS4]

even on a big block?

[Czech-it-Out Graphics]

all motors generally if u dont ur fuel maybe combust too soon, and cause pitting on the head button, there is a big discussion about it on a .28 in the Novarossi thread on the S-grid. U can always run it and check for pitting or see if the glowplug coil gets smushed then add a shim from there. Almost all motors are shimmed for 20%

[DAVEC-NITRO-RS4]

I thought I recalled that 20% was the baseline and you have to watch it going up from there. Shimming, etc as required. And that it was touchier on smaller displacement motors.

[Czech-it-Out Graphics]

ya 20% is baseline, that will change when u increase the nitro content, u will need a greater deck height but u still get more power. It is mostly a wear issue. If u run 30% on a motor shimmed for 20%, (I am not saying this will happen in every case and will vary b/w motors), u may have a motor that is just a bear to tune, because a half hour either way will make u overly rich or overly lean, the motor will prolly run faster, but it wont be long till u pull the rod bushing throught the bottom of the con rod

[Tex]

I always run hot plugs with 30% and never reshim.... I've had good luck so far so I won't change anything. I'm not saying reshimming wouldn't help cause I'm sure it does but....In my case I've been alright.

[Sh1nn3r]

I was thinking the same thing. P5 and adding another shim due to 30% percent i dont know about that. I started it and ran it today wow this thing hauls ass!! P5 wohoo!