DYNOED.......my 16V turbo - PeachParts Mercedes-Benz Forum

Clinton · #1 02-06-2003, 06:05 PM

Hello there,

OK, I finally got my car dynoed.........the results?? Well, the HP figures weren't exactly what was expected.....but the Torque really surprised me.........I haven't scanned the graphs yet but I will, and show you all, however, here are some numbers. This is a Chassis Dyno. My max HP I hit 181.6HP to the rear wheels. Figuring a 25% drivetrain loss.....what is that? about 227HP to the crank? Don't know if I'm doing that calculation right. And I got 204ft/lb. torque to the rear wheels!......this is what? 255.5 to the crank? Much better than expected......of course my calculations might be a bit off. Well, I'll try to get those graphs scanned asap.......later.

super SEC · #2 02-06-2003, 07:39 PM

That is a good dyno run for your car. If you figure a 25% drivetrain loss, you have 242.13 horsepower to the crank. I bet you car rips along quite well. The last time I dynoed my supercharged SEC, I recorded 314 RWHP and 361.4 RWTQ. Assuming a 25% loss in my drivetrain, I have 418 crank horsepower.

Benzmac · #3 02-06-2003, 08:22 PM

The Mercedes Auto transmission will usually calculate to about 20% loss. The standard is about 15-17%.

What was you max rpm? HP and Torque should cross at 5250, so if you dynoed to 5250 or above, you should have more HP than torque.

The equation is as follows. HP=torque*rpm/5250

Horsepower is FIGURED, not measured. This is strange I know, but the only thing you really ever measure is torque. The hp is a result of that torque above 5,250 rpm.

(Boy I hope I am saying this correctly.)

super SEC · #4 02-06-2003, 08:40 PM

Benzmac,

Quote:

What was you max rpm? HP and Torque should cross at 5250, so if you dynoed to 5250 or above, you should have more HP than torque.

Not necessarily. Here is my dyno graph: http://boards.rennlist.com/upload/dyno.jpg I hit peak horsepower at 4800 rpm and the hp and tq curve cross at 4500 rpm. Keep in mind this is RWHP and RWTQ.

Here is a pic of my engine bay: http://boards.rennlist.com/upload/SECengine4_WEB.jpg

I'm running 12 psi of boost in my 5.6L engine and uing a methanol/water injection to control boost. My dyno charts are from runs made before I added the water/methanol injection. At the time, I had my timing retarded around 10 degrees at full boost but with the water/methanol injection I can run full boost and full advance. I will dyno the car again when my custom headers are finished. With the headers and water/methanol injection, I hope to dyno between 370 to 400 RWHP.

Benzmac · #5 02-06-2003, 09:29 PM

I too see that....Hmmm.

I went back and looked at my past dyno results and found 1 that printed like yours.

However, the same car printed differently on the later runs. It is possible that one of the settings is off on your dyno pull.

On mine, the data of max HP and Torque was correct, but the rpm points were wrong for some reason. I am looking into this now.

Thanks

super SEC · #6 02-06-2003, 09:54 PM

The problem with the horsepower curve, IMHO, is the ignition retard in these runs. I would imagine if I didn't have to retard my timing by 10 degrees you would have seen a greater and more linear increase in power.

EuroCoupe · #7 02-07-2003, 01:58 PM

Is anyone else interested in that 560SEC rather than how to calculate hp vs. torque??? superSEC, where did you get that setup? Do you have a low-compression U.S. motor or a Euro? E-mail me back rather than start a whole new discussion here...

Thanks- Mike

Jim Villers · #8 02-07-2003, 03:54 PM

Clinton ... I also just dyno'ed my 16v ... posted the plot on my old "didn't return from the track" thread My numbers look in the same ball park as yours (especially when I get my belt problem fixed).

#9 02-07-2003, 04:04 PM

Quote:

Originally posted by super SEC
The last time I dynoed my supercharged SEC, I recorded 314 RWHP and 361.4 RWTQ. Assuming a 25% loss in my drivetrain, I have 418 crank horsepower.

Only macaroni, thats freakin sick

Do you have any pictures of your car? Is it a custome build turbo or a Koneing turbo kit? Thanks

Clinton · #10 02-07-2003, 05:28 PM

Well the torque curve is like this.
1500 @ 100
2000 @ 111.5
3000 @ 194
4000 @ 204.4
4500 @ 195
5000 @ 185
5500 @ 175
6000 @ 150

The HP and Torque curve cross at about 5250 RPM (like what you said Donnie)

HP is like this.

1500 @ 30
2000 @ 41.9
3000 @ 115
4000 @ 155
4500 @ 165
5000 @ 177
5500 @ 181.6
6000 @ 175

So after 6000.....things start to go downhill. BTW, this dyno didn't measure tranny loss. Well, let me know what you think.....I'm still going to post the graphs later on.....
I love how the TQ jumps all the way to almost 200 at just 3000 RPM's and stays right up there until it crosses with the HP curve. Makes for nice acceleration. Also here is the deal.......we messed with the little screw behind the air flow meter and richened the mixture up a little bit to 11.9:1 while under boost. Well, we noticed on the dyno that we lost about 11HP and 12 ft/lb with the mixture richened up. So, I wasn't going to do that.........we leaned it back up to 13:1 under boost. This is where I got the best power numbers. Well, what do you think I should do? b/c when the boost kicks in....that piggy back fuel computer that Mosselman sent me richens the mixture when boost pressure is sensed.....however, it richens it up too much to where I'm not getting the best mixture while under boost. I guess I need to contact Mosselman to see if I can adjust the fuel computer while it is boosting......that way I can lean it out just a tad. OR maybe I can invest in a more powerful ignition system....that way I can use that extra fuel for more power. OR maybe I can turn up the boost and lean it out that way??? HMMMMM........I just want some opinions.....thank you.

Jim....that is great!! My HP and torque curves look almost identical to yours.......mine are just a tad bit higher

Seems like your car is coming along great! Well, keep in touch. Later.

super SEC · #11 02-07-2003, 07:05 PM

Evo II,

The kit is totally custom made. Here are a couple pics of the car:
http://boards.rennlist.com/upload/560SEC1.jpg
http://boards.rennlist.com/upload/BackofSEC.jpg

Enjoy!

Jim Villers · #12 02-07-2003, 07:29 PM

Clinton ..... What were the boost pressures during your dyno runs? Boost is magic; I blew a duct during one run and horsepower dropped 40%.

I agree with the discussion that less retard and a slightly leaner mixture may increase horsepower but it comes at significantly increasing the risk of damage to the engine from pre-ignition or too hot of combustion. I have seen burned pistons and an eroded head and want my engine set up very conservatively.

What I really appreciate is the flat torque curve that really makes the car pull strongly through the gears.

Clinton · #13 02-08-2003, 07:28 PM

Hey Jim,

Mine stayed at 6psi almost consistently.....however, I did notice it drop to maybe 5 at around 5000RPM's. I noticed that yours dropped a little too right during the run? What do you think about my dillemma here? About the too rich mixture at boost? How should I solve this? Try to lean it out? Get a stronger ignition system? or turn up the boost and lean it out that way? Thanks everyone.

super SEC · #14 02-09-2003, 02:42 AM

Quote:

On mine, the data of max HP and Torque was correct, but the rpm points were wrong for some reason. I am looking into this now.

Benzmac, you got me thinkin'! Your right, the hp and tq curves should cross at 5250 regardless of timing or anything else for that matter. Do you think the dyno place connected the sensor to the wrong plug wire???? I'm not sure if this would make a difference? What ever the case, I'll ask the dyno shop what the deal could have been. If anything, I thought the hp and tq numbers were dissapointingly low for the amount of power this supercharged engine seems to have. The SEC really cooks with 12 psi of boost!

Boost causes issues if you don't have everything bolted down. For a while, I was blowing everything off the intake: hoses, vacuum lines, air bellows, idle air control unit, ETC... I had to reinforce the back of the air bellows with epoxy and use hose clamps on everything else. I even had to bolt the CIS unit to the intake because it kept separating around the throttle body. The car runs great now but there was a definate learning cuve during the tuning process.

Jim Villers · #15 02-09-2003, 08:22 AM

I would like to get some comments on my tuning objectives. My tuner says that a 9.7:1 compression engine at 6 psi of boost should have about 20 degrees of ignition advance and 12:1 fuel air mixture.

My dyno runs were targeted to achieve these parameters, not the maximum horsepower.

Anyone have comments on the parameters.