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-   -   Looking for Timing Specs (https://www.rctech.net/forum/offroad-nitro-engine-forum/779616-looking-timing-specs.html)

dbuck 12-19-2013 01:15 PM

Looking for Timing Specs
 
What are the timing specs for the engines that are used for nitro off-road racing?
Looking for:
Exhaust duration
Transfers duration
Boost duration
Crank duration
Blowdown
Head clearance

Recommended Nitro/oil percentage ?

Thanks,
David

Roelof 12-19-2013 02:03 PM

http://www.first-racing.eu/steuerzeiten.html

dbuck 12-19-2013 02:41 PM

Thanks for the link!

Interesting to note that most of those engines run under less than 180 degrees exhaust timing considering the high rpm's they turn. Still would like to know what head clearance racers are using. On my .21 it's set at .006 .

David

wingracer 12-19-2013 03:02 PM


Originally Posted by dbuck (Post 12827520)
Thanks for the link!

Interesting to note that most of those engines run under less than 180 degrees exhaust timing considering the high rpm's they turn. Still would like to know what head clearance racers are using. On my .21 it's set at .006 .

David

While an offraod .21 may be capable of 40k rpms, how often and how long do they get there on an actual track in race conditions? I have never seen telemetry or data logger info from an offroad car but my guess is that it only happens when all four wheels are off the ground. Probably 90% of the time the motor is somewhere between 18-30k.

Onroad, it's more like 25-40k, thus more duration.

Roelof 12-19-2013 11:18 PM

In my list mostly onroad engines: http://www.euronet.nl/users/tooms/timings/timings.jpg

Head clearance is determed by the combustion chamber. Older Novarossi's were set to 0.7 and later are set to 0.55. Picco is at 0.5 or even 0.4 so far I have seen (@ 25% nitro). Also the headclearance is set by the nitro percentage.


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