I'm getting a baseline dyno on my car next week and wondered if anyone can give me some information on settings to run the car on the dyno.

I assume you need to shutoff the ESP with the button on the dash and set the trans to "1" instead of D and let her rip from there. Anything else I should know to optimize my experience?

 

I believe you want to do a 3rd gear pull, where are you doing your baseline?

 

I am doing the dyno pull at Curry's in Ashburn at the same time that they are doing a brake fluid flush/fill and tech inspection for the March 8 and 9 Summit Point track weekend.

If I am doing a third gear pull I assume you mean to put the trans to "3" so it will not shift up past third gear?

 

1. ESP off
2. W mode selected
3. Hold shifter to left so 2 is displayed
4. Use light throttle to build up speed
5. When transmission shifts to 3rd, 3 will display
6. Continue to build up throttle pressure until about 3800 rpm when you can go all the way down on the throttle as at that engine speed, it will not shift
7. When you see 4, your done

 

Thanks for the detailed info! Why use "w" mode? You don't want the transmission to be down into first at all since you are just measure the power once it hits third gear?

 

Just the way I was told to do it. I think it is might be to avoid slipping in first gear and plus it is a little easier to keep track of just a single gear change. You might consider trying both W and S mode and see if there is any real difference.

 

Yea, a single gear change is much easier. The 1500rpm lurch in W mode is really noticable on a dyno.

 

Rage2,

If I recall correctly you added Koni Yellows to complement your RENNtech springs. Out of curiousity, where did you get your shocks? I have a tough time finding anyplace showing an application for a C32 or SLK32.

I understand that the W mode will start me off in second gear so I got the idea here. Besides starting in second I don't think there are any differences between W and S so W shouldn't have any negative effects on my dyno numbers.

 

i think I have heard of Curry's through some BMW guys, let us know how you do.

 

There is no "specific" application for the C32 or SLK32. Koni yellows were the ones for the SLK 230/320 (8041-1228Sport fronts, 8041-1229Sport rears). I'm using stock springs, with the thinnest pads (therefore allowing me to stay in A stock). Camber is dialed in to the negative side of factory spec. For winter I have the front set to full soft, with 1/2 turn of the knob for the rear (full soft all around oversteers a bit too much). In my limited dry weather testing a few months ago, I dialed the car in with 1/2 turn of the knob front, 1 turn of the knob rear. I don't think I got any extra grip over the stock setup, but I did dial out some of the mid speed understeer that our cars had from the factory, which should help turn-in a little better.

I'm willing to bet that the W203 set would work fine for you. 8741-1412Sport fronts, 26-1679Sport rears. I'm not sure how the Koni part # designation goes, but it looks like the rears are not knob adjustable... you have to drop the shock to adjust it, which is quite annoying (like my 944 setup).

There aren't any differences in power at WOT, but in W mode it does resist downshifting a lot more than S mode.

 

Rage 2,

What's the deal with the Mustang Dyno? I saw your other post about them showing low numbers and someone else told me the same thing when the shop where I am going had a dyno pull event.

I certainly don't want to handicap my car from the start with a dyno that makes it tough to get good numbers. On the other hand a supposedly stock SLK 32 pulled 296 horspower on it's first run on the Mustang dyno; the second run saw heat soak bring it down to 290.

 

See here :

http://www.activeautowerke.com/dyno/...gVsDynojet.asp

Personally, I don't use dyno numbers as a reference to how much gain I'm getting unless everything is done on the same day/same conditions. The calibrations play a huge role, and it's not perfect... I've seen Kenny's car do a 255rwhp run, and a 270rwhp run the next day (different weather calibrations). The math isn't perfect to calculate power for every single car out there for a given set of conditions, so unless the runs are back to back, it's worthless. Change in power is what's important. A dyno is really a tool for tuning, being able to dial in A/F and timing (relatively close anyways) without using a lot of road. I remember I once tuned my 944 turbo in 4th gear... reading wideband logs at 120mph. Not exactly safe .

Like I said, all due to calibrations, weather conditions, etc. It's quite easy to enter the wrong info and get wild variations in power numbers. On my car, I've done 5 back to back runs with 90 second breaks, water temps keep going up but I keep making 1 or 2 more hp each run . Maybe the cooler canadian weather keeps the car from heat soaking hehe.

 

I braved a snow/ice storm, terrible traffic and past four accidents to get over to my appointment for the tech inspection, brake fluid change and the dyno run. Temps were mid 20's outside and it was a nightmare. I didn't think it was that bad until I already was out and the stock pilots aren't the ticket for snow/ice. W mode and ESP got me there ok but I'll never take it out in that stuff again.

The dyno run was unbelievable. I am attaching the graph/print out because nobody will believe it otherwise. My car is stock except for the 93 fuel setting (I watched the tech set mine on the laptop) and newly added K&N air filters. I made some runs with the filters for the first time last night before the snow so the ECU could hopefully learn the filters. I always run Sunoco Ultra 94. The best number was 323.8 hp at the wheels and 316.1 torque. I saw the same dyno and operators run a SLK 32 (it's one of the techs father's car) at a dyno pull off two weeks ago with 35 degree temps. He pulled 296 hp on the first run then dropped to 290. My car definitely looked like it was pulling stronger than the SLK 32 and I got some nice video.

I inquired about the variables and the shop said he first entered the weight at 3,400 lbs and then ran a control run for the dyno to figure the weight by how many horsepower it took to push the car at a certain speed. I don't know what to think other than the temps, fuel setting, 94 octane and clean K&N's were working.

 

Carl: A couple of questions for you:

1. How did you get the car to stay in a gear without downshifting?

2. What weight did the operator used for SLK32?


Stock C32 is around 3600 lbs. Looking at your numbers, is the reason why I am leary of Mustang and Dynapack dynos. Operator can manipulate final HP/TQ numbers by playing with a number of variable. On a DYNOJETS everything is locked.

 

I wasn't driving the car (or operating the dyno) but the car was in winter mode and I believe they were using the tips that were detailed earlier in this thread that provided helpful advice before the run rather than questioning the results afterward. They were familiar with how to make it run on the dyno because of numerous runs with the tech's father's SLK32.

I don't know what weight was entered as I merely witnessed the SLK run but as explained to me they put in a initial weight then run a control drive that calculates weight based on horsepower need to drive to a speed.

No one manipulated any variables after the car began to make the runs and they have no vested interest or care what my numbers were. They don't sell any Mercedes tuner products.

I must say I'm not suprised by your reaction. I wonder what the numbers would have been if I didn't lose hp with the K&N air filters?

 

lol!

 

Your buying Carl's numbers rage2? Your the one with the
experience on a Mustang Dyno, are they even close to your experience? What weight did you use?

It is not even SAE corrected. Maybe DIN?

Norm

 

I'm just laughing at his joke .

But yes, dynos (not just mustangs, dynojets too) can be deceiving at times, that's why final numbers dont mean much to me at all since I don't bench race... it's the change between the mods on the same day that's important. And of course 1/4 mile and laptimes .

 

Rage2: I disagree with you with regard to dyno being different from day to day. In my experience of dynoying in the past seven years and of over 1000 cars - if you are using SAE correction numbers you will be very close. Less than 0.1%.

This is very true on a DYNOJET, since there are no variables to play with. In other words you can not change drum mass - it is fixed, or change load by adding brake. The only variables are humidity, altitude and atmospheric pressure. And those are taken care of by SAE correction factor.

In mid90s we ran the same car on three different DYNOJETS. All three graphs overlaid one another. SO one can use DYNOJET numbers from any other DYNOJET dyno for comparision.

Carl: As far as your numbers. Do not get me wrong, but you have one of the strongest stock C32s. I am assuming it is stock, since I have not read otherwise. If it has ECU and pulleys than it is about right.

 

My post details about the weather conditions, etc. weren't to give a weather report but to detail what I think must have contributed heavily to crank out the numbers. I can't begin to imagine it was SAE corrected to normalize atmospheric conditions and generated those numbers. Any of us they have operated a C32 in cold weather know how much faster it feels in those conditions.

Does anyone know what the correction factor would be for SAE to put the numbers into perspective; I'd be happy to give you the variables other than I don't know what the temp was inside the shop itself (maybe 50 degrees)? I would have asked if I knew about it when I was there and would be very interested.

But in terms of questions about manipulating factors to show numbers is ridiculous. I wouldn't know how to if I wanted to, have no incentive to want to post high numbers, and I agree with rage2 about bench racing. My point about the SLK 32AMG on the same dyno was to put things into perspective. Would ten degrees warmer outside temps and a higher barometer make a 25+ horsepower difference? Could it be the 93 fuel setting, 94 octane and some high flow air filters? When I saw the SLK run at the 290+ range, though strong, that seemed reasonable with what I had heard our car's would put to the wheels.

The 93 fuel setting (with a car that has access to that fuel) seems to be such a mystery. How much of ECU bump are we getting from this setting? I don't think anyone producing and selling chips would be too thrilled if it actually had a impact. I know Vadim questioned whether people actually have this setting even when they request it but I know from my own eyes that mine was changed; I was right next to the technician and his laptop when he changed it.

 

OK...so I got on the internet myself because my curiousity was peaked to see what the SAE factor would do to my numbers given my assumption that it wasn't corrected and found this site and their engine tuner calculator:

http://wahiduddin.net/calc/calc_cf.htm

I got all the weather variables and altitude from NOAA's website with yesterday's readings from Dulles International Airport (which is about a mile away from the shop) and I'll ignore any issues about Mustang Dyno's showing lower numbers than a Dynojet. With an assumption that the shop temp was 45 degrees the correction factor is .943 leaving me with 305.34 hp. If I assume we were outside the shop freezing in 25 degree temps the factor is .921 leaving me with 298.21 hp.

 

Why don't you have a race with another stock C32 if you know someone who has one or at least the SLK32. If it is a C32 and you really do have a hot car, then you should easily walk away from him. The comparison with the SLK32 isn't as good but if you can pull away from it or even stay even then maybe you do have particularily hot car. If, however, you are even with the other C32 or can't quite keep up with the SLK32, then you'll know that something is wrong with dyno results. A rolling start from say 40 or 50 mph to 100 or 120 should tell be enough for you to tell.

Sometimes you do get a faster than average car, maybe you got lucky and are in the 99.9 percentile. However, the difference is so big that it indicates that something wasn't right.

 

Carl: You are misunderstanding me. I am not accusing you of playing with numbers. What I am saying - if there are variables that a dyno operator has to input in order to test your car, the possibility that the dyno operator will make a mistake is high. Resulting in a wrong HP/TQ data.

 

See my SAE correction factors/numbers above. I just wonder if you would question the variables on an unusually high dyno run if I just installed your ODPS kit?

 

Carl: I posted right after you, so I did not see your post.

As far as me questioning your numbers if they were with ODPS, yes I would. If the numbers were SAE, than I would of wanted to know what makes a bigger difference on your car than on the others. It also works the other way, if you car did not make the power from ODPS like others than I would want to know why it is also the case.