tuning question - hot and cold

[simonrc]

Tuning question again for the pro's...

When i first star the car (xtm mammoth), I have to gently build the revs or otherwise it will bog and die. However, when its warmed up I have checked my temps I'm hitting 250, its giving plenty of smoke. I can let it sit for 20 seconds then punch full throttle and she flies away.

I dont under stand why when cold i have to gently build the revs (i mean very gently too i.e. the car doesn't move for 5 seconds) but when warm it can sit and blast off the line.

I would say if it did it all the time that I needed to lean my LSN slightly but I'm just not sure. Can someone confirm what I should do plea

 

[10 Gauge]

All nitro's for the most part like this. Maybe not as touchy as you describe but I have to very gently ease in to the throttle, sometimes it will die 2 or 3 times before I can get it to rev high enough to gain speed.

The combustion chamber has to be warm to allow the piston to move smoothly across the sleeve and the heat + compression is actually what ignites a lot of the nitro in the chamber (almost exactly like a diesel engine). The glow plug only ignites enough fuel to keep your motor running when cold. That's why once it's up to temp it, it riiiiips, as all of your fuel is being burned more efficiently.

 

[dub c]

sounds like youve got your tune spot on to me!

 

[Rolex]

Absolutely.
For ANY internal combustion engine to run its best it needs to be at running temp which requires some warm up time.

 

[simonrc]

Absolutely.
For ANY internal combustion engine to run its best it needs to be at running temp which requires some warm up time.

So its normal and I can't do anything about it? I have other cars that don't do that.

 

[mtaylortank]

i have 4 tmaxx's and they all act different for some reason.but yeah alot of the time you gotta let warm up before you bash.

 

[simonrc]

i have 4 tmaxx's and they all act different for some reason.but yeah alot of the time you gotta let warm up before you bash.

thanks guys. much appreciated

 

[2revo1maxx]

+1 all my engines will idle nicely at startup but it takes a little finess to get 'em revving. I always baby them until they reach about 120-150 degrees.

 

[mtaylortank]

Yeah I dont like getting on mine too hard while it is still a little chilled thats a good way to snap stuff.. And I have ran mine in 10 to 20 degree weather up here in maine.... and no problems and then I have a friend that has a jato and he had alot of bad luck because he never let his motor warm up at all and sometime he would keep it in his truck during the winter take it out and run it.... Definetly dont do anything like my friend did because you will replace your motor alot... I had sold him the jato in mint condition I wish I woulda kept it cause he never learned his lesson and now the jato dont run no more...... A crying shame... I had the gears for the Jato to hit 85mph now she does 0mph.

 

[hamz9561]

Even full sized engines in our 1:1 cars used to be that way until fuel injection became more common. I had a friend that had a 1965 Mustang and the 289 V-8 was a very cold-hearted pig and wouldn't run right until it was up to temp.

 

[michaelmcgau]

takes time warming up to running temp, next time u drive ur own car look at the temp gauge, ul see it wont run as well until its warmed up.

 

[Rolex]

I can't do anything about it?

It's not that you CAN'T do anything about it, but rather that you SHOULDN'T. All my engines were tuned to behave that way.

 

[michaelmcgau]

at the end of the day, who cares. be soft with it for the few mins it takes to warm up then go out, have fun and try not to break anything. 2 out of 3 will do lol