M20 885 Cylinder Head w single valve spring

[digger]

Maybe I don’t understand, but if the SETA cam has less lift - how can it be re grounded to be a performance camshaft. I thought the performance camshaft would have a higher lift and duration to allow more air into the chamber. Thanks Sent from my iPhone using Tapatalk

The SETA cam has a bit more lift than the B25 cam based on data i've seen but the duration is very small thats why it is junk for power. You can perhaps theoretically regrind by reducing the basecircle and some do hard weld grinds but there are better roads to go down

[ForcedFirebird]

but the duration is very small thats why it is junk for power.

Trapped mass is a tricky subject. To say "junk for power" is subjective if you include torque lol. Trapping mass helps get things moving, but they fizzle out up top. :/

digger
I am surprised the seta and eta have the exact lobes - was it only the bearing count that's different?

[digger]

Trapped mass is a tricky subject. To say "junk for power" is subjective if you include torque lol. Trapping mass helps get things moving, but they fizzle out up top. :/

digger
I am surprised the seta and eta have the exact lobes - was it only the bearing count that's different?

yes, i mean good trapped mass/VE at higher rpm. An eta cammed engine is hardly a torque monster havent seen a dyno of one for many years. its probably more for fuel efficiency and part throttle

I'm not sure if they are the exact same lobes, my only involvement in that graph was supplying the Alpina cam

[ForcedFirebird]

yes, i mean good trapped mass/VE at higher rpm. An eta cammed engine is hardly a torque monster havent seen a dyno of one for many years.

Max power with 2.7i: 145whp, 145wtq

Changed the intake from 325i to 325e, added 325i TB and ground TB to "i"spec, 145whp, 170wtq.

Fresh m20b25 ready for spec class, 169whp, 159wtq.

2.7 crank, "i"pistons, stock cam : 180whp


You know me, Digger.....

[digger]

Max power with 2.7i: 145whp, 145wtq

Changed the intake from 325i to 325e, added 325i TB and ground TB to "i"spec, 145whp, 170wtq.

Fresh m20b25 ready for spec class, 169whp, 159wtq.

2.7 crank, "i"pistons, stock cam : 180whp


You know me, Digger.....

i was more talking about a single variable, say take a bone stock ETA (or SETA) throwing in the "B25" cam or Alpina Cam (with valve springs) without the different intake/TB etc i dont think you are losing much torque with the additional duration as it is still fairly mild.

[Motorsport1207]

Measured both cams i (K) cam and the SETA. Both lobe circle is similar 1.094 - 1.100. Both lobe heights are the same. 1.360- 1.369. lThe duration on the SETA cam is much shorter. See pic. Don,t really see a need for the SETA cam. I am just going to convert this 885 head with dual valve springs and a “K” cam. Sent from my iPhone using Tapatalk