Originally posted by wangcc61
I have some STS engines for awhile and finally taken measurement of their porting. I modified the exhaust port and intake timing on my engines for experiment. The result is better top end but slightly less punch. Good for smooth and large track. I just want to share the data to STS fans. Ok. here they are.
STS RS3
Schnuerle: 112 degree
Boost: 108 degree
Exhaust: 162 degree (mod.)
Induction(stock): 207 deg. (30 ABDC - 57 ATDC)
Induction(mod.): 212 deg. (30 ABDC - 62 ATDC)
STS D5
Schnuerle: 118 degree
Boost: 116 degree
Exhaust: 162 degree (mod.)
Induction(stock): 204 deg. (30 ABDC - 54 ATDC)
Induction(mod.): 212 deg. (30 ABDC - 62 ATDC)
I will take the measurement of my D3 next time.
I got the following data from rc magazine
Collari .12
Schnuerle: 114 degree
Boost: 114 degree
Exhaust: 159 degree
Induction: 213 degree (32 ABDC - 65 ATDC)
It looks like the induction of STS opens 2 degree sooner than Collari .12
By the way, if the crankshaft is lightened, say 1 or 2 gram, the engine will have quick acceleration from low rpm to high rpm. But the idle might not be as stable as stock one. Just need to tune the bottom and idle needles again, and it will be fine. Not sure if it is legal for ROAR to lighten the crankshaft....
Great info Wang, but could you tell us what was original exhaust degrees before moding???
Ref. crank, yes you can lighten it, ROAR rules have no restriction over moding cranks, they are similar to IFMAR rules....but wacht out for balance.
AFM