ForcedFirebird's m20 dyno thread.

[digger]

Apples are not Apples, Get back to us on a dynoJet corrected in SAE.

Your 5252 cross is not at 5252.

agree on using a meaningful point of reference such as DJ, dyno dynamics or Maha which cant just fudge like many others.

the 5252 cross doesnt occur because the y-axis scales for power and torque differ

[moatilliatta]

Apples are not Apples, Get back to us on a dynoJet corrected in SAE.

Your 5252 cross is not at 5252.

[digger]

bro if i cant get 200whp out of a higher compression 2.7i w itbs imma push it off a cliff

Just do it properly and should be ok

[MrBurgundy]

bro if i cant get 200whp out of a higher compression 2.7i w itbs imma push it off a cliff

[2mAn]

Here are some stock 2.7i dyno results from my old setup. Overall, pretty solid and expected for a 'junkyard' motor/ combo. I wonder how much this could've gotten cleaned up with either a chip-tune, or an aftermarket EFI.



Here is the dyno of the '2.8i' post installation after removing the 2.7i. Bottom end is an eta with the 81mm crankshaft and some 10:1 Ross Racing pistons that were sourced from (I believe) Ireland Engineering years ago. Unknown camshaft and no real headwork. Camshaft is mild because this is a street motor he built for a client a while ago. I am dreaming of ITBs for the future... but for now I will enjoy the nice bump

[2mAn]

MrBurgundy I expect to see some new dyno plots from you here soon, 200WHP or BUST...

[AliBOSS]

It's not an 85.8mm stroke but a 3.0 crankshaft from an m54 that we balanced and lightened. So we are talking about 89.6mm

The diesel block we used the block only and adapted it to accept the 885 head. We didn't use bigger pistons, because the diesel block wouldn't support more than 84mm of boring from previous experience.

The block is actually longer that's why we used it, also a lot of modifications and grinding has been done to be able to rotate the crank without the rods hitting the cylinder wall.

Also we are using one of the worst pump gas quality wich is the only available.

[digger]

Those are some of the highest m20 numbers I have seen. I want to know every detail of this motor! I've never heard of an m20 diesel block before or anyone using 140mm rods in an m20.

MM were using 140.5mm rods 20 years ago. The diesel block is an m21 and it is where the forged 81mm crank comes from that Alpina used in their engines, and where the the high flow oil pumps that are sometimes mentioned come from.

[2mAn]

I'm not sure, we are using stock parts from other engines, nothing is forged. The static compression is around 180 but our giant retarded camshaft is lowering the numbers

Trying to break this down a little more with my failed ME math

84mm Bore X 85.8mm stroke = 2853cc or a solid 2.9L

Compression Ratio is still a mystery because US S50 had 135mm rods, EU S50 had 142mm…

What fuel does the motor like?

[88Sedan]

Those are some of the highest m20 numbers I have seen. I want to know every detail of this motor! I've never heard of an m20 diesel block before or anyone using 140mm rods in an m20.

[AliBOSS]

Those are some impressive numbers!! What’s the compression ratio on your setup

I'm not sure, we are using stock parts from other engines, nothing is forged. The static compression is around 180 but our giant retarded camshaft is lowering the numbers

[2mAn]

Those are some impressive numbers!! What’s the compression ratio on your setup

[AliBOSS]

Good Morning everyone,
I would to share with you our Frankenstein M20 that we finally dynoed 1 week ago

It's diesel block, 885 hand ported head,Dbilas open M5 3.6 itbs with their trumpets, 3.0 crank knife edge and balanced and 84mm pistons on 140mm rods, electric water pump and fan, mechanical pump deleted. Standalone ecu tuned by me.

[zaq123]

I meant thrust crank clearance.. I'm sure you got it but just in case.... Thrust bearing is the reason you should not use an impact wrench on that crank bolt btw. Hand tools only

[McGyver]

I appreciate both of your perspectives on this! The cylinders have all been bored for 0.50mm over pistons, main and rods have all been cut and bored to match the crank. Plastigauge will confirm there weren't machining mistakes. It would be cool to get the actual measurements, but I don't think that justifies buying tools with enough precision to provide a real measurement.

I plan to file the ring end gaps per cylinder for a Turbo application. I'll also measure/swap piston/rods to get even piston height at TDC for all six cylinders. And I'll balance the piston assemblies as best I can. I'll also check valve clearance to the new guides with the new cam and check piston to valve clearance with the new-but-crushed head gasket. Should be good!