ForcedFirebird's m20 dyno thread.

[darvo]

Yup, the 84 would be perfect my main problem is availability where I live. Live on a little island

[digger]

Get one sent to your little island. It will be worth it though getting the original crank you had planned is probably better as the bottom end and midrange torque will be a lot better

[ForcedFirebird]

my guess is the differences are mostly breathing mods

looks like that cam isn't doing shit

Swapped the diff out, it was smoked. I couldn't even turn the output flanges by hand once it was on the ground. If it was that stuck static, I could only imagine how much it was dragging at top speeds. I wondered why the graph kinda went flat from 5-6000rpm, then dipped, were m20's usually have a smooth curve that peaks at 6k.



Again, not sure that car will go back to the dyno anytime soon, but will see what I can do.

[ForcedFirebird]

Yup, the 84 would be perfect my main problem is availability where I live. Live on a little island

Get one sent to your little island. It will be worth it though getting the original crank you had planned is probably better as the bottom end and midrange torque will be a lot better

I agree with Digger. Should be able to get one shipped from the states to PR.

[darvo]

Thanks Guys! I'll keep an eye on a 84mm, aint 89.6mm bad for rod/stroke ratio?

[SLEEPYDUB]

Thanks Guys! I'll keep an eye on a 84mm, aint 89.6mm bad for rod/stroke ratio?

I have an 89.6mm S52 crank for sale if you're interested. Can ship to your island if you pay for it. Crank was recently polished within spec, balanced, and even comes with the snout spacer you'll need for the M20. Message me if you're interested in it

[ForcedFirebird]

I have an 89.6mm S52 crank for sale if you're interested. Can ship to your island if you pay for it. Crank was recently polished within spec, balanced, and even comes with the snout spacer you'll need for the M20. Message me if you're interested in it

He needs the 84mm and has the 89.6 (which is putting his pistons way out of the deck - hence the .100" gasket plan).

[SLEEPYDUB]

Ah my bad

[digger]

He needs the 84mm and has the 89.6 (which is putting his pistons way out of the deck - hence the .100" gasket plan).

His pistons are originally intended for 89.6 so he should get that but he'll need to get the 135 rods to go with it.

[darvo]

He needs the 84mm and has the 89.6 (which is putting his pistons way out of the deck - hence the .100" gasket plan).

The pistons are 12:1 for 89.6 and 135mm rods, but the m54 block disappeared after Hurricane María.

I only got a E block laying so, I was looking for 139mm rods to use with a 81mm to match the deck height but only found 138mm to use with the pistons.

The 0.100 gasket is to lower the compression to 11.2-11.5, I would like that CR with my current cam.

[darvo]

I have an 89.6mm S52 crank for sale if you're interested. Can ship to your island if you pay for it. Crank was recently polished within spec, balanced, and even comes with the snout spacer you'll need for the M20. Message me if you're interested in it

Pmed for shipping quote

[E30-325iS]

Nice Dyno #'s! I recently purchased a set of 12:1 85mm Vac 885 head pistons for a 89.6 and 135mm stroker build but the m54 block I had in mind was thrown away before I got to it.

The pistons are 12:1 for 89.6 and 135mm rods, but the m54 block disappeared after Hurricane María.

I might be missunderstanding what you are trying to say but you can't put an 885 head on a M54 block.

[digger]

He was going to remove the rotating assembly from it

[ForcedFirebird]

Again, not sure that car will go back to the dyno anytime soon, but will see what I can do.

Welp, it definitely won't be dyno'd again. Raced the cars last weekend and had a couple minor issues - but the 168hp car definitely pulled on the 180hp car in the straights - but the 180hp car ended up making better lap times due to it having coil overs - pretty sure the diff was causing some serious parasitic losses on the dyno.

After 315 laps on a 2.6mi course, I was driving the 168 hp car and it lost oil pressure in a high speed right hand sweeper with 5min left after 14hr of racing. I heard the noise/knock, looked down at the gauges and saw the oil pressure at 10psi and dropping fast (was at about 3500rpm). Got the car back to the trailer and pulled the dip stick, it was almost a quart low. Our fault. We hadn't checked the oil the entire race as we had a small couple small issues - fuel filter clogged from surface rust in the tank (it sits a lot), and later on in the race the crank sensor started acting up. We got so zoned in on these items, we never bothered to check oil level.


At the Road Atlanta circuit, the 168hp car was able to put down a 1:50 and the 180hp car put down a 1:48 - both on 200 rated street tires and mid-level drivers. Fastest e30 of the day put out a 1:45 in which I had the pleasure to lap with on my last stint, that car was just as quick on the straights, but they clearly had a much better driver (or suspension) as he was able to shake me in the corners.

[earthwormjim]

How valuable would an audible alarm be for oil pressure? Or is it too noisy to be heard in a racing environment?