Got a 21 , maybe shifting from 50% to 70%

[Tofastformellow]

i am curious in the benfits to make the jump , but how do i best use this extra bang ??

when changing from 50% nitro on a stock 21 valv direct

to 70% nitro nitro on a 21. ??

generally speeking ..... to get the benefit where do i change first ??

do i prop up ?

lengthen or shorten the pipe ?

drop or raise the strut ?

richen or lean the mix ??

cooler glow plug req ?

drop the oil content back ..

we have been running 20% oil overall. (heaps)

am thinking about mixing up 16% oil , maybe 18%

and 70% nitro by volume

been told to run 12% oil , witch sounds fair but thats not much oil at all..

and if the tank gets a supply hickup wont that blow the top of the motor.??

LOL's & Thankyou

Jason

 

[John Knight]

Jase,

Consider the following:

* Drop oil content to about 15%. I use all synthetic but if you want to use castor drop the 5% castor.

* Shorten pipe about 1/4" (start there) to about 1/2"

* Richen needle about 15 to 20%

I would leave all else the same. Change too much you are chasing your tail for possibly eons. One theory is do not change too many things at one time as you may not find out what is NOT working. Just MHO.

John

 

[Don Ferrette]

70% nitro & 12% synthetic oil. B)

 

[tnrcboatracer]

I have some LB625 I'm dying to mix into fuel. I assume 12% is a good ratio for this majic mystery lube?

 

[shoboat]

Jon,

The LB-625 works well, 12% will be about right. We ran as low as 6% oil this year with our 21's,

and we had no real issues. The oil is very important,but what combination that you use is the

real issue. Blends work very well.

Have Fun,

Mark Sholund

 

[Chris Wood]

personally just for me.. i would never run 12 percent oil.. if you like changing bearing's alot then that is up to you..

that is just me but what do i know.

chris

 

[Jerry Wyss]

Kinda Big jump from 50 to 70, there's some in between there that work perdy good too.

 

[Tofastformellow]

Kinda Big jump from 50 to 70, there's some in between there that work perdy good too.

yes i would have to follow that logic ,

70% keeps coming up, so there must be some merit ,. and these little buby engines dont drink much overall. its not like im trying to run a 90 on 70% couldnt afford to do that !

just would like to know what should be changed ,

Thankyou DON , for your helpful PM's

Thanks guys keep it coming

Jason

 

[Don Ferrette]

personally just for me.. i would never run 12 percent oil.. if you like changing bearing's alot then that is up to you..

that is just me but what do i know.

chris

It all depends on what type of oil you use Chris. Too much oil can be actually be worse as the balls can wind up skidding in the races rather than actually rolling. Believe it or not, my bearings started lasting a little longer when I cut back on the amount of oil I was using in all my motors. I run 15% in everything over a 21 including my 90's. Keep in mind this also requires discipline with the 3rd channel needle. B)

 

[Tofastformellow]

Jon,

The LB-625 works well, 12% will be about right. We ran as low as 6% oil this year with our 21's,

and we had no real issues. The oil is very important,but what combination that you use is the

real issue. Blends work very well.

Have Fun,

Mark Sholund

6% oil , holy batman !!!

Jason

 

[Brad Christy]

Jason,

I've been running 65% nitro and 16% oil for a couple years now and it seems to work well. For oil, I use a 50-50 mix of the Klotz KL-100 and KL-200, which works out to 10% of the oil is castor. The mix is far more important than the brand.

The thing to keep in mind is that the more nitro you use, the les oil you need in the mix, because the more nitro, the richer the needle setting, therefore more oil going down the throat.

I have also seen what Don F. pointed out about the oil content and bearing life. If you look closely (low power microscope) at a dead set of bearings, you can actually see the skidding marks.

Thanks. Brad.

Titan Racing Components

BlackJack Hydros

 

[steve wood]

just dump in the 70. you may be able to shorten the pipe(what pipe are you running) you'll just turn a bunch more revs. shouldn't have to do anything else unless the boat isn't set up right with 50

 

[Tofastformellow]

just dump in the 70. you may be able to shorten the pipe(what pipe are you running) you'll just turn a bunch more revs. shouldn't have to do anything else unless the boat isn't set up right with 50

the pipe that i have on it SPP td21 . its Cranking up fine..

the others i have tried are all good also ,i dont see much difference between them.

saving a few grams with carbon ... :lol:

h4 , h5 , 1716 are all working and throttleing well. on 50%

but i would like to launch a v9 , and maybe a nice h6 ...

i think i need to reduce oil content .. a tweek

Jason

 

[Chris Wood]

just dump in the 70. you may be able to shorten the pipe(what pipe are you running) you'll just turn a bunch more revs. shouldn't have to do anything else unless the boat isn't set up right with 50

the pipe that i have on it SPP td21 . its Cranking up fine..

the others i have tried are all good also ,i dont see much difference between them.

saving a few grams with carbon ... :lol:

h4 , h5 , 1716 are all working and throttleing well. on 50%

but i would like to launch a v9 , and maybe a nice h6 ...

i think i need to reduce oil content .. a tweek

Jason

jason,

if you want to make more power.. going from 50 -70 percent will make HUGE gains over tweaking oil content..

trust me, i know what the gains are and once you do you will not go back.

the only thing you will need to change is the needle

chris

 

[Roxyflash]

All that oil must be doing something to get US1

 

[Tim_Duggan]

Jason,

What heat times are you running on 50%?

Tim.

 

[Tofastformellow]

Ive sent you an email Tim

Jason

 

[Tofastformellow]

Thanks chris i will try that ....

and thanks to others ..

Jason

 

[jason jury]

Thanks chris i will try that ....

and thanks to others ..

Jason

jason.. get a modified head button.. 50% nitro ..ssp ms pipe with reducer in the stinger outlet hole of 0.284.. prop stabdard h5 , or h4 with between 3.1 and 3.4 f cup.. this set up will be fast .. very good and consistabt for heat racing trim,, no need for 70% nitro ,, keep the extra bucks in your pocket.. ..just my 2cents.. jase .. bro racing ,, melbourne ,, australia. 51

 

[Tofastformellow]

Thanks chris i will try that ....

and thanks to others ..

Jason

jason.. get a modified head button.. 50% nitro ..ssp ms pipe with reducer in the stinger outlet hole of 0.284.. prop stabdard h5 , or h4 with between 3.1 and 3.4 f cup.. this set up will be fast .. very good and consistabt for heat racing trim,, no need for 70% nitro ,, keep the extra bucks in your pocket.. ..just my 2cents.. jase .. bro racing ,, melbourne ,, australia. 51

Hi jase .. how are you over there??

what have you done to your head button , send me a pm.

Jase