Marauder Torque Drop

BUCKWHEAT

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Two years ago I had the MM engine dynoed. results: 487 RWHP & 494 torque. No mods in between then and today when I had another shop dyno the MM. Results: 481 RWHP, about the same, and Torqued 431, down 63 #feet. Both were Dynojets.

What might cause Torque drop? Bad tranny, bad TC, bad fuel delivery? Any thoughts?
 

ProRauder

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A dyno is just a tuning tool and no two are identical. Since horsepower and torque are a function of the same thing, the question you have to ask yourself is, "does the car feel down on power?"

Did it have a fresh tune-up?

New O2 sensors?

Air temp and density different?

The point is, there are a lot of factors that determine the outcome of a dyno session. I doubt you could get two identical pulls a year apart and on different machines. It just won't happen.
 

Zack

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I think the 494 number was a fluke.
Go compare your setup to those with similar mods and you will see no one makes near that.

And also remember, 'tooners' can shove timing in on a dyno, make the number and back it off when they program your device.
 

BUCKWHEAT

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A dyno is just a tuning tool and no two are identical. Since horsepower and torque are a function of the same thing, the question you have to ask yourself is, "does the car feel down on power?"

Did it have a fresh tune-up?

New O2 sensors?

Air temp and density different?

The point is, there are a lot of factors that determine the outcome of a dyno session. I doubt you could get two identical pulls a year apart and on different machines. It just won't happen.
thanks, Zack. It doesn't seem down on power. no tune in two years. Wednesday I will take it to the track with real slicks & see what happens. At the recent dyno, both temp and humidity were down compared to two years ago. I will check the 02 censors. No codes tho.

John
 

kmastl

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John,

Go Friday to midnight madness!
 

Zack

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thanks, Zack. It doesn't seem down on power. no tune in two years. Wednesday I will take it to the track with real slicks & see what happens. At the recent dyno, both temp and humidity were down compared to two years ago. I will check the 02 censors. No codes tho.

John
I hope you have skinnies up front with slicks.
Scary and dangerous with slicks on a MM.
Stick with DR's
 

4DoorBlackTop

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I would change them if I were you. I would change mine every year and noticed a difference every time. Remember, boost eats plugs.
 

BUCKWHEAT

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Let me know what happens.
Changed out the spark plugs, replacing the NGK TR6 at $2 each. Cheap. Old ones w/ only 7K on them looked (uniformly) like crap. Ran the M/T 28x10.5 drag slicks to a new personal best 60' time of 1.857. Ran the slicks at 15# and, as Zack predicted, it got scarry loose so I got out of it, running a 15.5 at 60 mph. Going again next Saturday & will pump up the slicks, starting at 25# to see if that will keep the 60' time but firm up sidewalls and the rest of the run.

Any day at the track is a good day.
 

4DoorBlackTop

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Lol it is a cold day in hell if I told you how to fix your car and it worked.

Muhahaha

Good job with a new personal best!
 

LANDY

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Bringing tire press up won't help that much. If u want to safely run bias plys you need skinnies up front and tubes on a soft sidewall.
 

BUCKWHEAT

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Bringing tire press up won't help that much. If u want to safely run bias plys you need skinnies up front and tubes on a soft sidewall.
Thanks, Landy. My front wheel problem is the 6 piston wilwoods won't clear the smaller rims. Any suggestions for rim size that will still support a bias ply skinnie? admittedly, I haven't looked yet. I can try the slicks on the front to check clearance-humorous perhaps...
 

Zack

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Thanks, Landy. My front wheel problem is the 6 piston wilwoods won't clear the smaller rims. Any suggestions for rim size that will still support a bias ply skinnie? admittedly, I haven't looked yet. I can try the slicks on the front to check clearance-humorous perhaps...
You have 2 marauder rims narrowed to the recommended width for skinnies
 

BUCKWHEAT

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elevens

Today at Gateway Motorsports Park was a day just ahead of the rain. Temp was 60-ish with lots of wind. Did four runs on the Nitto 555DRs at 22# with VHT on the track:
60 foot ET MPH
2.025 12.260 116.50
1.991 12.235 116.18
1.840 11.927 117.25
1.943 12.149 115.75

That third run is my first trip into the elevens and my personal best. Thanks guys, for all the suggestions.
John
 

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