Dyno Run with center cat removal
Thread Starter
Junior Member
Joined: Jan 2002
Posts: 70
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From: Beverly Hills
2017 C63 | 2018 E63
Dyno Run with center cat removal
I've noticed some people were confused as to whether removing the center cats would cause problems in addition to power losses. I removed the cats last week and had the car dyno'd to see the results. I don't have a base run to compare these figures to, so I can't say for sure how much I lost or even gained, but I am very satisfied with the results. The car put down 353HP and 377ft.-lbs of torque (taking into account a 20% driveline loss since it is a V12 automatic). So these figures appear to be right on the money...I might have lost a little bit of power because I do have exhaust/intake, but the difference is negligible. Car feels a lot smoother now on topend...doesn't feel as restricted.
http://www.renn-sport.net/stuff/CLK55_dynorun.mpg
http://www.renn-sport.net/stuff/CLK55_dynorun.mpg
Member
Joined: Nov 2001
Posts: 116
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From: Dallas
CLK55
Different Dyno different 55...
Your run does not look much different than my 55 Baseline run with cats / resonator intact. Renn-tech did your dyno? Reputable to be sure. Lincoln (not sure if he is on the list stillsince he now has a M3) went with me to Norwoods to do my runs. Bob Norwood is a a Ferrari guy so I he definately didn't have anything to gain / sell me by dorking with the dyno results.
Do you have the raw numbers from your run? I could lay them down against mine on a spreadsheet and see if your making gains anywhere that I am not. Right now you'r not making any more wheel hp / torque than I am stock. Did you run with the stock 17s? That could be the difference right there. Bigger rims / tires will zap some performance.
If you want my excel spreadsheet - just drop me an email - bodyart27@aol.com
Do you have the raw numbers from your run? I could lay them down against mine on a spreadsheet and see if your making gains anywhere that I am not. Right now you'r not making any more wheel hp / torque than I am stock. Did you run with the stock 17s? That could be the difference right there. Bigger rims / tires will zap some performance.
If you want my excel spreadsheet - just drop me an email - bodyart27@aol.com
Out Of Control!!
Joined: Nov 2001
Posts: 35,855
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From: Southern CA
You miss read his link. Renn-sport did his dyno, not Renntech. It would be much more helpful if there was a stock run to compare the dyno to. From there, you could not only see the difference, but find the % loss from factory HP claims in order to see what the new engine HP is. Without an original dyno to compare it to, there is no way to know if he gained or lost power. Also, without the cats, while HP may go up, torque will most likely go down.
Thread Starter
Junior Member
Joined: Jan 2002
Posts: 70
Likes: 0
From: Beverly Hills
2017 C63 | 2018 E63
Yes, I'm running 19X9.5 BBS LMs in the rear, so that might explain the difference in torque. However, you could also have a stronger engine than me. It's no secret that no two engines are alike from the factory. Either way...I'm sure I definitely lost power by taking off the cats, but the losses were not detrimental. I just wanted to see for myself...I will most likely put on some high flow cats soon to see whether I can gain back what I lost, while still keeping the lovely sound 
I don't have raw numbers...only the raw dyno chart. I will email you that.
BTW...the dyno run was at R&D Dyno in Carson CA...not RENNTECH.
I don't have raw numbers...only the raw dyno chart. I will email you that.
BTW...the dyno run was at R&D Dyno in Carson CA...not RENNTECH.
