ForcedFirebird's m20 dyno thread.

[dvallis]

Das Beast 2.8L turbo stroker M20

See Build Thread page 1 for specs

BLACK : 6 psi
RED : 10 psi
BLUE: 16 psi
GREEN: 19 psi

[ForcedFirebird]

I'm not sweating it Keith, it's relevant. What did you do for the CPS?

Right on dvallis.

[dvallis]

'Bird this is a great thread. Will be sure to post my dyno run here.

[whodwho]

yes there is only one but i'm against incorporating additional idlers, tensioners into the Vee belt system for the additional cost, points of failure and maintenance.

You threw me on the 'timing belt'. You could run without the tensioner and idler and just use the manual adjusters and would be 100% stock BMW non maintenance parts. it allows to run a newer damper and one that's tuned (if there is any real difference) for the 84mm crank that I am running. I also have a ATI damper for my S54 that I am seeing what I can do for a hub.

it would make more sense on an M30 which needs the extra space

Or a supercharger setup 8^)

(ignore the alternator holding up the SC, that was just to hold it while checking the SC > plenum > throttles alignment)

Only options ATM are using a 24v damper, which is larger in diameter and has the OlT mark at 2 o'clock vs 10 o'clock (easy fix), will require custom CPS bracket and either change to vee belt damper, or serpentine alternator other oprtion is totally a custom /adapted unit.

Sorry for derailing your thread I though it was relevant to your post, I will make a new thread

[digger]

yes there is only one but i'm against incorporating additional idlers, tensioners into the Vee belt system for the additional cost, points of failure and maintenance.

it would make more sense on an M30 which needs the extra space

[whodwho]

one tensioner on the timing belt is more than enough....

I don't understand your statement?? There is only one

[digger]

one tensioner on the timing belt is more than enough....

[whodwho]

Funny timing, here is a recent project that might be relevant 8^)

[digger]

i just want to see which part is rubber and some basic dimensions will probably do if it is cut up a bit

i think i have a solution for the ATI option for the M20 that retains all the pulleys locations with little more than some modified front covers. there are a couple of options i came up with based on ATI's initial work to fit their recommended Inertia ring.
- one option allows the stock OE crank gear (albeit the new version) and 24V 95mm long centre bolt used for a typical stroker which is ideal. will be discussing with them in coming weeks.
- another options a new gear that integrates to the damper but means the big M18 bolt needs to be removed to change the timing belt which is not ideal. this will add a fair bit of cost to the already expensive price so fingers crossed the first option can be taken from concept design to a detail design.

[ForcedFirebird]

any chance you could cut it up and measure the rubber bits and steel so i can model in CAD and do some calculations? you could always send it to me

Not likely as he is about 1300 miles away, but can ask.

[digger]

Apparently the stock crank damper does not like 8000 RPM.

any chance you could cut it up and measure the rubber bits and steel so i can model in CAD and do some calculations? you could always send it to me

[digger]

Years ago MM used to produce a light weight version of the vibration damper. they no longer do this, i wonder if they encountered issues doing that as it goes against modern thinking

[2mAn]

Metric Mechanic has been producing 7700pm engine for a minute, might call Jim as see what his thoughts are, but right now need to get the car back on the track.

If you call Metric, you will need more than a minute, Id set aside an hour or two lol

[ForcedFirebird]

what engine was that from?
All the other rubber bits degrade with heat, time and stress so this is no different. i bought a new damper for this reason.
i was in discussion with ATI to but not looking promising as the water pump and alternator drive is in the way so you cant get enough thickness

New dampeners are NLA. We have been searching for a week. This is the SCCA National champ, 208whp/184wtq b25 12.5:1compression and our head work. Hoosier came out with a new stickier compound and it was a testing day. Crested a hill at the top of 3rd and was 500rpm more than usual due to exit speed. Tapped 8000rpm and BOOM! This motor has been running for 2yr, nly was able to squeeze 2nd place last year. (1" porting rule mentioned earlier in the thread, stock sized valves).

Only options ATM are using a 24v damper, which is larger in diameter and has the OlT mark at 2 o'clock vs 10 o'clock (easy fix), will require custom CPS bracket and either change to vee belt damper, or serpentine alternator other oprtion is totally a custom /adapted unit.

Metric Mechanic has been producing 7700pm engine for a minute, might call Jim as see what his thoughts are, but right now need to get the car back on the track.

Just for giggles, let's listen to the music of my peoples!

https://www.youtube.com/watch?v=WdgIqhFOw80

[LowR3V'in]

still it did great for 30 years. my stock nissan blew up at only 20.