Markert Motor Works Dyno Thread (many inside)

[digger]

The most high RPM and HP:CC ratios have large bores, long rods and short strokes.

Ideally, if the piston can outrun the flame front, there is no time for detonation, but we will never see that in an m20 (or other close rod/stroke ratio engine).

the piston wont out run the flame front because the piston speed is relatively slow during the burn phase but certainly at higher rpm knock is less/lower issue due to both reduced time and extra turbulence. most engines fall within a certain mean piston speed so outrunning flame speed which would be bad for developing cylinder pressure isnt an issue

if you compare a 3L engine 86x85.8mm vs 84x89.6mm then the large bore option should make more hp due to reduce shrouding and/or being able to fit larger valves which helps airflow and hp potential, if none of those offer meaningful benefit / are an issue or implemented on the particular engine in question then the only benefit in general is the reduced friction due to shorter stroke.

[Jaker]

But generally a longer stroke engine will produce more area under the curve to the left of the dyno graph.

[digger]

But generally a longer stroke engine will produce more area under the curve to the left of the dyno graph.

if you add stroke and stroke alone then yes, if you trade stroke for bore (within reason) and do nothing else the cylinder fills just about the same and the torque curve isn't altered any meaningful way by the change in VE characteristics. the engine mostly cares about the rate of change of swept volume the bore/stroke ratio and rod length are second order effects as far as VE goes when you dont change the induction or exhaust (frictional effects are a different story)

[ForcedFirebird]

... and the torque curve isn't altered any meaningful way by the change in VE characteristics

I have found on a regular basis (all else being equal) that engines do in fact pick up TQ when bore is increased. Not by much, but it is measurable.

[digger]

Absolutely, an increase in displacement will always bring more torque. Sometimes you even get disproportionate gains

[shootnjunky]

You guys going to the vintage?

Would love to get a tune done by you guys

S52 swapped obd1 m50 manifold

[The Dark Side of Will]

Absolutely, an increase in displacement will always bring more torque. Sometimes you even get disproportionate gains

When you can go from a 2.02 intake valve with a 4.000" bore to a 2.125" valve on a 4.125" bore... you betcha it'll pick up torque...

[digger]

I was meaning even without a change in induction. Because the cam acts smaller the port speeds up into the sweet spot so you sometimes get more bottom end gains than a simple prorata

[pazi88]

Most of the 3L strokers I see using m54 parts make low power...

If only the rotating assembly is from m54b30 making the engine 3l, then yes it will not make much more power (if any) than b28. Only more torque (as was said before). The fact that m54b30 make more power is the more agressive intake cam. The cams in engine mostly dictates how much hp it can produce. The displacement dictates how much torque it can produce. Putting m54b30 intake cam to stock m52b28 will make 220-230 hp from the crank with tune. But torque will be much lower than m54b30 because of the displacement difference. Torque is basically how much air can get in the engine in single rotation. And power is how much air you can get in the engine in given time. In m5x engines the cams are the thing that restricts the airflow at higher rpm.

Of course there are other things that have effect also. But those are the two things that mostly have affect in m5x engines.

[mitch500]

Pmed

[Sh3rpak!ng]

Need more dyno graphs in here! It's been a while...

Anyway - Dave I spoke to you about 5pm your time regarding a tune I ordered for my e36 convertible - 2.8 w/s52 cams, M50 intake and EWS delete - you helped me confirm EWS functionality with the EWS deleted (basically I do nothing :D )

Just thought I'd give you a shout out here. Can't wait to receive it and drive the car on it. I never actually had the car properly tuned in the 8 years I've had the manifold and cams installed

and rereading much of this thread just really makes me think I ought to revisit the tune on my s52 e30... there're some seriously strong dyno graphs on fresh rebuilt s52s with not much more than a solid exhaust, m50 manifold and 3.5 maf/intake..... and I've got some euro s52 headers plus all the 3.5" parts on hand

[shootnjunky]

So what is the concensus on differences between mustang dyno and the one you guys use?

I have your tune and it ran 208hp/206tq on a mustang for my s52

Maybe I need to move up to the 3.5 maf, does that require a new tune and do I send the ecu back or can it be remote now?

[ForcedFirebird]

So what is the concensus on differences between mustang dyno and the one you guys use?

I have your tune and it ran 208hp/206tq on a mustang for my s52

Maybe I need to move up to the 3.5 maf, does that require a new tune and do I send the ecu back or can it be remote now?

The ls1 uses the same size MAF and has no problem supporting 400hp. No need to run a MAF larger than the TB, as it's not a choke point.

[shootnjunky]

The ls1 uses the same size MAF and has no problem supporting 400hp. No need to run a MAF larger than the TB, as it's not a choke point.

So the 3” one I have for my obd1 config on the M50 Manifold is correct then?

I thought I could go up injectors and maf and end up with a few more ponies?

[ForcedFirebird]

So the 3” one I have for my obd1 config on the M50 Manifold is correct then?

I thought I could go up injectors and maf and end up with a few more ponies?

Injectors and MAF aren't going to make more power,larger injectors are only needed if you are making enough power to max out the stock ones. I just did an s50 build a few months ago and made 255whp on the stock pink s52 injectors with plenty of room left in them.