Guys,
Afshin dyno'd his car and his sheets are up...see here
As Joee's car did, the torque peak was very early, ~3200rpm, but looks more nomalish. He sais his car didn't hit the 1.2b due to not enough load from the dyno they use?
Last time the dyno numbers from Afshin were corrected by the dyno. Not sure about these. It's very peculiar that the torque and HP falls off so early. I mean, the graph ends at 5380rpm.
Todd
The discussion there was there was no reason to go past 5200rpm, as theres no more power to be had with a stock engine, and thats correct. I usally shut my dynos down ~5500rpm, for the same reason.
[QUOTE="russc"]The discussion there was there was no reason to go past 5200rpm, as theres no more power to be had with a stock engine, and thats correct. I usally shut my dynos down ~5500rpm, for the same reason.
RussC[/QUOTE]
How come my stock m30b34 made power all the way to 6250rpm?
This was one of our very first dyno runs. 15psi non intercooled. Untouched motor. Prototype everything. T04b-H3 turbo, etc.
your power curve is flat, you didn't make any more power that would be useful for testing. Most stock turbo M30s as you know don't dyno that way. The torque falls faster than rpm can increase, so the power falls off after ~5k rpm. The M106 is even worse as the cams are different and hurt top end power more than the b34s. The b35 is a little different, as the better head and cam breath better above 5k, so theres more there to see. Especially with more work to the head or a higher duration cam, but those hurt low/mid end torque.
What makes the power fall off ? Where is the intake flow restriction? If you dump the AFM and upsize all the tubing up to the TB, upsize/polish the TB, are the 6 intake valves and the head still limiting you to power-fallof at 4500rpm? That doesn't sound like much fun :/
[QUOTE="TCD"]the m106 ans m30b34 are essentially identical. Cams are the same.[/QUOTE]
The key is "essentially". That implies, not the same. I believe this is part of the reason the M106 makes torque sooner, and fall off earlier. There are a host of other very little things that make the M106 different from the "b" series M30s.
What makes the power fall off ? Where is the intake flow restriction? If you dump the AFM and upsize all the tubing up to the TB, upsize/polish the TB, are the 6 intake valves and the head still limiting you to power-fallof at 4500rpm? That doesn't sound like much fun :/[/QUOTE]
What makes the power curve of the M30s look that way is mostly head design then cam and intake manifold.
First, the head design is poor for upgrades. The geometrys for air passage ways are poor. The design also limits valve size. And, it's not 4v/cyl, thats a limiting factor.
Next, cam is designed for low end grunt, not good top end power. That can be fixed with better cams, as were proved in the 345i and Todds 745i.
Intake desing will never breath well at higher RPM with those long runners. It was meant for low end grunt. It's needs to be changed to much shorter runners for better breathing.
All this info has been discussed, mostly in the dyno threads, check them out.
[QUOTE="russc"]Intake desing will never breath well at higher RPM with those long runners. It was meant for low end grunt. It's needs to be changed to much shorter runners for better breathing.
All this info has been discussed, mostly in the dyno threads, check them out.
RussC[/QUOTE]
There are equations that can be found for the proper length and radius of runners tuned for a certain rpm. This applies to both intake and exhaust if you are into fabrication. I think I found them in a V8 engine building book. I'll see if i can find them again.
the M106 is verymuch the same as the normal M30, the reson that todds cars hold there power fairly stable to the end is cause of his turbo it supports much more power than the k27 that is the #1 biggest difference in these engines.
What makes the power fall off ? Where is the intake flow restriction? If you dump the AFM and upsize all the tubing up to the TB, upsize/polish the TB, are the 6 intake valves and the head still limiting you to power-fallof at 4500rpm? That doesn't sound like much fun :/[/QUOTE]
I don't think these numbers suck. Matt you do realize that the numbers are metric right? 532 Nm is almost 400 ft/lbs of torque. That's none too shabby in my book!
The M30 and M106 motors may not be that different in mechanical aspects. They do have various differences such as compression and cooling. But by far the biggest difference is in how they are tuned and boost control.
The stock toque output on the M106 motor was quoted by BMW at 380 Nm at 2,200 RPM. The fact that the M106 produces the most usable power at low RPM makes it a different animal than the M30, which BMW quoted at MAXIMUM torque at something like 310 Nm at 4,400 RPM. (Correct me if I'm wrong.)
That's why the guys that stick M30 heads in their M106 cars (with all the M106 trimmings, low compression pistons, etc.) generally do not complain about any drivability differences or other issues. With the M106 DME, the Franken-motor ran just about the same as it did with the hard-to-find M106 "turbo" head.
But if you try to run a M106 with M30 DME, you get all sorts of drivability problems. (Ask me how I know...I bought Elliot's 645csi for a song after he couldn't get it to produce high power reliably. The easy fix? Simple, just bolt on a M106 DME, injectors, boost control, etc... Problem solved. Car sold.)
I think the answer to this age old question might be a reliable dyno test. When my Silver car is done maybe Russ and I will go and put it on the rollers and try to get a concensus on what it will do.
The car isn't that close to being done yet as I have been side tracked with my 1967 1602. But maybe this summer we'll get around to it and we'll post the numbers.
[QUOTE="scottiesharpe"]I think the answer to this age old question might be a reliable dyno test. When my Silver car is done maybe Russ and I will go and put it on the rollers and try to get a concensus on what it will do. [/QUOTE]
[QUOTE="scottiesharpe"]I think the answer to this age old question might be a reliable dyno test. When my Silver car is done maybe Russ and I will go and put it on the rollers and try to get a concensus on what it will do. [/QUOTE]
[QUOTE="TCD"]Now this is something I would love to see![/QUOTE]
I guess well make video of it if you need to see it that bad. I look forward to the dyno time, would be real fun Scott.
