Can someone explain this shitty dyno graph? (m50, s50 cams)

[JGood]

Yeah, I switched half way through my hour commute this morning, so had a 1/2 hour with each chip of mixed driving conditions. There's no difference between them. The idle smoothed out and the powerband smoothed out with both. Which also concerns me, as a "M3 cams" chip should produce significant gains over a normal chip, with m3 cams...

But I guess I need to verify my vanos is operational first. Because unplugging it didn't make a difference.

[White325is]

Well, that's not normal. That's over 300 crank horsepower, stock is 240. Most stock s50's dyno ~210 on a dynojet that I've seen. With tuning and bolt-on's, usually 230-240. This wasn't at their shop, it was on a dyno trailer at a car show. I would normally just write it off as being improperly set up, but my buddies s52 putting down normal numbers right after me kinda has me worried.

Thats what I thought. But thats what it was. I drove the car for almost 2 hours to get to the dyno. It sat for about an hour before I got on it and it was about 90 out..
All I have done is headers and exhuast.

[JGood]

Thats what I thought. But thats what it was. I drove the car for almost 2 hours to get to the dyno. It sat for about an hour before I got on it and it was about 90 out..
All I have done is headers and exhuast.

Hmm. I'm obviously no tuning or dyno expert, but I'd like to see that engine on another dyno. That's a pretty sloppy looking top end, usually the look pretty smooth up top, no? That goes from 240hp to 260hp in less then 200rpms, then back down to 230hp. That would be felt as a pretty noticeable surge, wouldn't it? Either way, that 200 lb/ft at 2000 RPM's must feel nice

[White325is]

It does drop down. I actually had trouble with the ABS kicking in. I did a search and it seem to be a problem with two other people. The way they fixed it was pulling the ABS ecu and relay. I didnt get a chance to do this because I did know till I got home and posted a thread. Some had said about it so thats when I started looking..
Heres a video

[JGood]

Sooo, it turns out that the vanos uses the same type of 2 pin connector as the coolant sensor. But my coolant sensor connector was unused, I ran a new wire with a spade connector for my m20 coolant sensor (required with the m50 swap). So here is this 2 pin connector flopping around, and over a year ago, when I put in my s50 cams, I decided to plug my vanos into that apparantly.

So I haven't had vanos since I put the cams in 12 months ago.

I'll say this, the car is a whole new animal down low. Matt from TRM is sending me a new tune to try to correct my top end (above 5.5k, where vanos is turned off). It's either that or timing causing my power loss up there. I guess it's just a coincidence that I lost the same amount of power from vanos being unplugged down low, as I am missing from the top end currently.

And all this time, I thought my car was running great. LOL.

[dude8383]

Haha damn man, well at least you found the source of the problem!!

Another trip to the dyno?

[JGood]

Haha damn man, well at least you found the source of the problem!!

Another trip to the dyno?

Yes, eventually. It will happen sooner rather then later if I can't feel a difference with the TRM chip, because then I'll re-time the engine, and get back on the dyno for back to back runs with the four chips I have (stock, ebay knockoff, AA M3 cam chip (which I believe is a knockoff), and the known good TRM cam chip). Otherwise, if the TRM chip feels really good, I'll just keep it in, and redyno the next time I find a cheap dyno day.

I cna't believe how good the car feels right now!

[FredK]

insert sheepish hick laugh here



_____________________

[JGood]

Fixed! Here is a run on a dynapak with vanos connected. AA tune is the thick lines, TRM tune is the thin lines.

She makes a wee bit more power now :)

[JGood]

Here's some more interesting results. Thick line is a generic ebay AC Schnitzer m50 chip, not tuned for cams or anything obviously. Thin line is the AA chip.

[JGood]

All three chips were run on the dyno probably 5-6 times before getting the final run, to get underhood temps and oil temps equal between all of them, and for the DME to adjust. Air intake temps got pretty close between all of them (~72 IIRC)

[StereoInstaller1]

Wow, what a difference that graph shows.

I assume you paid the extra $20 this time?

Which tune drives best? To me, I would guess the TRM tune has best driveability, ya?

[JGood]

Wow, what a difference that graph shows.

I assume you paid the extra $20 this time?

I had it run on a proper dynopak with the AFR, air intake temp, etc... hooked up. Much more legit then the mobile trailer dynojet. It's also $100/hr, vs $65/3runs. Much better value. I did probably 20 runs total, and got quality information.

Which tune drives best? To me, I would guess the TRM tune has best driveability, ya?

Look at the top graph again. The TRM and AA tune put almost the same power down except for 4700-5700, where the TRM tune drops down pretty bad (almost 20whp). Which I'm guessing is due to a pretty huge drop in AFR, shown here (again, TRM thin lines, AA thick lines):





I sent these over to matt to see what he thinks, as he's been helping me sort through my issues with this engine.

I don't feel a power difference between the two chips (20whp in a specific RPM range is kinda hard for me to feel, believe it or not), and there's definitely no "driveability" difference to me. Both tunes are smooth and pull strong. I didn't drive around with the AC Schnitzer knockoff chip as the AFR is all over the place from 1k to 6k, although it matches the other 2 tunes above 6k and actually makes more power, somehow (only 2-4whp though, not much).


The TRM tune did make 2-4whp more from 1k until 4.5k, though.

[JGood]

It should be noted that my engine was timed by me, and I'm not a professional mechanic. These results are from a 250k mile motor that I have been tinkering with. If you have a stock rebuilt m50, and are looking for a tune, don't go off of my results as far as which vendor to chose. Who knows what I've messed up as far as cam timing or simply running the shit out of the engine. I just don't want anyone to think I'm knocking TRM's tune due to the weird AFR's my engine made. You can see the AA chip did the same thing, just not as extreme, and later in the RPM's.

[StereoInstaller1]

Right on, thanks for the info. My S50 is bone stock and will only get an exhaust (ebay headers and dual 2" all the way back, X behind the "true dual" cat, some kind of dual muffler, UUC style) and my goal is smooth and torque-y, heavy traffic street driven with occasional mountain road blasting...