Changed fuel brand, is this normal?

[Motha Trucka]

I have been useing Traxxas Top Fuel 20% since I got my truck and car, but I ran out and the LHS was out of Top Fuel. The hobby guy told me that Trinity Monster 20% was pretty close to Traxxas 20%. I used it for the first time last evenning, and the X always ran around 240/245 with the Top Fuel, but with the Monster fuel it was running around 296, so I richened the HSN, it took 2 tanks of fuel, and I had to turn the HSN about 3/4 of a turn counter clockwise, in serveral small incriments before I finally got the X within safe operating temp, about 240. Is this normal when there is a change of fuel type?
Paul the book

 

[SunkenMetal]

Yes, when you change fuels you need to Retune....Stick with Trinity, that top fuel stuff isnt that great......

 

[Jeremy]

I run trinity .. Its so much better you will like it once you retune .. try to get 30% tho it will lower your temps,

 

[romper4444]

From my experience it will not lower your temps, in theory running an engine on higher nitro content will lower your temps, but you have to richen the HSN and LSN to compensate for more nitro in turn lowering your temps, but assuming that your engine will run cooler on higher nitro isn't true, from my experience alot of RTR motors will not like 30%, especially 33% fuel as you often have to add a few head shims as no amount of richening will bring your temps down. My Savage runs hotter on 30%, but I also broke it in on 30%, I can keep the temps around 250-260, instead of a nice 215-220 with 20%. After I added a tuned pipe, I could just not keep the temps below 280-290 and peaking past 300 on repeated HS runs, I could richen the hell out of the HSN to the point where it was blubbering on the top end, but still couldn't bring temps down, thats even with an extra .2mm head shim. I now run 25% with the pipe and its a nice even blend of a little more power and temps of 240-250, still a little high, but fine I guess. Adding enough head shims to allow your motor to not overheat will take away the extra power (almost) that is gained from higher nitro content. trinity is an excellent fuel, probably my 3rd choice after byron gen 2 and O'Donnell. Trinity also makes 25%. You won't have to shim your head and will gain some power and can richen it up to allow for more safe engine running and still have the pep. One time I ran trinity 35% in my 2.5 maxx with a trx 3.3 motor upgrade, I absolutely had to go one step up of a head shim thicker from the traxxas shim pack, I could keep it around 300deg. but HOLY ****E did that thing scream, but Ijust couldn't run it very long as it would flame out in no time, the compression on traxxas motors is very high, thats why they overheat all the time and don't last, but man did it scream. The race uses that 33% traxxas fuel because I swear it comparable to top quality fuel makers 20%. i've seen the TRX motors on 33 and they don't run that hot, so somethings up there, most likely explains why you had to richen the HSN so much, you were finally giving that X what it needs!!!

 

[BiggC1981]

Hey man whats up i have been running 33%TopFuel for a year now in my X an i love it.My truck never gets over 220 an that racing it.Alot of guys don't like it and they want say why!My X will fly an I'm not running to Lean at all my last race mill i got 8gallons out of it be4 i got another 4.6