Quit blaming the engines, mileage vs. runtime.
12-09-2010, 09:41 AM
#16
Glad you guys liked the read. This is the kind of thing I think about when it's too cold to racing 
The whole point I'm trying to make is NOT there there is no difference between engines in mileage. The point is that it is my belief that today's .21's (.21's not .12's) with the pipe and fuel combos run by most pros are actually getting better MILEAGE than we used to get. It's the increased speeds of the cars that has reduced our runtimes.
.12's are a bit different story. The early engines were pretty primitive compared to today's. Plus the old exhaust height restriction means that today's engines are pretty different. Add in the fact that cars and tracks have gotten much faster and the drop in runtime has been even quicker. I used to go 8 minutes with my first TC and a side exhaust Nova .12.
The whole point I'm trying to make is NOT there there is no difference between engines in mileage. The point is that it is my belief that today's .21's (.21's not .12's) with the pipe and fuel combos run by most pros are actually getting better MILEAGE than we used to get. It's the increased speeds of the cars that has reduced our runtimes.
.12's are a bit different story. The early engines were pretty primitive compared to today's. Plus the old exhaust height restriction means that today's engines are pretty different. Add in the fact that cars and tracks have gotten much faster and the drop in runtime has been even quicker. I used to go 8 minutes with my first TC and a side exhaust Nova .12.
12-30-2010, 11:37 AM
#18
Tech Regular
I agree 100% with the Wingman.
The only way that today's engines can produce more power and more torque (and they do) than earlier engines, and that is with today's common 8.5mm restrictors, non-conical headers and 3 chamber pipes is because the engines are way more efficient.
While the modern engines are CAD/CFD designed and will swallow a lot more air/fuel through them, a considerably greater percentage of that mixture is actually part of the combustion process - more fuel is actually burned, in other words, producing torque and since, power.
That will make an engine more fuel efficient since the actual car will be displaced a greater distance per unit of fuel since the fuel is being used more efficiently.
Earlier engines passed a lot more of the mixture directly to the exhaust system without going through the combustion process.
XE
The only way that today's engines can produce more power and more torque (and they do) than earlier engines, and that is with today's common 8.5mm restrictors, non-conical headers and 3 chamber pipes is because the engines are way more efficient.
While the modern engines are CAD/CFD designed and will swallow a lot more air/fuel through them, a considerably greater percentage of that mixture is actually part of the combustion process - more fuel is actually burned, in other words, producing torque and since, power.
That will make an engine more fuel efficient since the actual car will be displaced a greater distance per unit of fuel since the fuel is being used more efficiently.
Earlier engines passed a lot more of the mixture directly to the exhaust system without going through the combustion process.
XE
12-30-2010, 01:49 PM
#19
Tech Addict
12-30-2010, 02:17 PM
#20
01-01-2011, 08:51 AM
#21
For my .21 engine : I am using lower nitro ( 20pct ) so I can lean the engine little bit more to make the time.
01-01-2011, 06:17 PM
#22
Tech Addict
As for timing, I wouldn't have a clue! I was by myself, but I felt that the pace I was running was up there, on a normal day Im 2nd/3rd, I can't beat the #1 guy, he drives too well for me to gain 1 more second per lap. This guy would just make he 6 mins with a little bit left at the end (Nova 12-3sct), the other guy about equal with me has about 1/2-1/4 left driving before the race without refuelling! (GRP Tuned I think) But Ive heard GRP engines are very fuel efficient as well, so that is perfect for this particular track.
Mine is a Picco JLR evo3, modified by AB Mods and by me as well, so it's a bit of a joint mod
01-02-2011, 08:53 AM
#23
heres something funny on my mrx4 at my local and chaplin ct track i never made runtime once very very fustrating tq pace 90%of the time and run out of fuel everyone tells me my clutch too aggressive i am a very aggressive driver on and off throttle too much im too fast bla bla bla, i tried every combo under the sun pipes, ventrui's, soft clutch, out the box big tires, 7 port 9 port everthing!!! but no luck... late september we got the mrx5 so we had over a month of racing left, since i got the 5 every quil every main every race!!! i was making over 5 min. only thing can figure the 5's drive train is so much more efficent its helping me make run time plus my lap times are faster by 3/10th's, i run flash special tuned, jp eagle 9, kangaroo, throuout the summer all had runtime issues same motors with the 5 no problems now....
01-02-2011, 06:08 PM
#24
Tech Addict
Awesome stuff Ralphie, but maybe it was something in the drivetrain in the 4 that could have been robbing you of power, which made you use up more fuel? Bad bearings? Just a few questions, thats all.
01-02-2011, 06:41 PM
#25
no nothing was wrong with the 4 just think the 5 rolls so much more freely that i can roll around the turns more instead of always being on the gas. what ever it is im just a very happy man now cause with the 4 at local racing i was going into cheat mode and using my pressure chamber as an extra fuel cell!!! lol
01-02-2011, 06:56 PM
#26
01-02-2011, 07:06 PM
#27
I haven't had a chance to check a five tank yet but 4 tanks were usually a couple cc's undersized. If the 5 is right on the limit, there's a few seconds right there.
01-02-2011, 08:13 PM
#28
beleave me i checked the 4 alot and changed the tank 3 times and yes it was alittle under but i used to use extra fuel line to make it perfect, now with the 5 its the same as the 4 with out the stopper in it and i run it with the stopper and make run time..
01-03-2011, 04:15 AM
#29
Tech Addict
01-03-2011, 08:57 AM
#30
no nothing was wrong with the 4 just think the 5 rolls so much more freely that i can roll around the turns more instead of always being on the gas. what ever it is im just a very happy man now cause with the 4 at local racing i was going into cheat mode and using my pressure chamber as an extra fuel cell!!! lol
If there is a big difference, I believe it can more easily come from the chassis, suspension and setup and that kind of things than just from the drive-train smoothness.
Just an opinion.
-X-
(-15Celsius and +60cm of snow today here)