When to dyno Again
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From: Tampa
Went to dyno Again
Well, some people we're doing midnight dyno runs for $20.00 so i did it again. We had to do it in 2nd gear which takes away horse power. it did 332.0 hp and 341.8 hp with the air filter removed.. its bone stock with 6500 miles on it.I think i'm going to buy the volant air intake.
Last edited by Supercrew04; Jun 13, 2004 at 02:59 AM.
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From: Fort Walton Beach, Florida
Re: Went to dyno Again
Originally posted by Supercrew04
Well, some people we're doing midnight dyno runs for $20.00 so i did it again. We had to do it in 2nd gear which takes away horse power. it did 332.0 hp and 341.8 hp with the air filter removed.. its bone stock with 6500 miles on it.I think i'm going to buy the volant air intake.
Well, some people we're doing midnight dyno runs for $20.00 so i did it again. We had to do it in 2nd gear which takes away horse power. it did 332.0 hp and 341.8 hp with the air filter removed.. its bone stock with 6500 miles on it.I think i'm going to buy the volant air intake.
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From: Lakewood, Southern Cali
You do realize that when you dyno in a gear other than 4 gear in our auto tansmitions you will get a very false reading. When dynoing in 2nd gear you are not at a 1:1 ratio in the transmition. You need to dyno in 4th gear buddy. Then, and only then, you will get an accurate reading. YOU NEED TO DYNO IN 4TH GEAR!!!!!!!!!!! And to let you know, dynoing in 2nd gear "gives" you power. YOU MUST DYNO IN 4TH gear. I seriously find it hard to beleive they let you dyno it in 2nd gear. The 5.4 3V makes 300-310 HP at the flywheel and means you should get somewhere around 230-250 HP to the rear wheels.
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From: Tulsa, O K L A H O M A!
Originally posted by sk8inrj1
You do realize that when you dyno in a gear other than 4 gear in our auto tansmitions you will get a very false reading. When dynoing in 2nd gear you are not at a 1:1 ratio in the transmition. You need to dyno in 4th gear buddy. Then, and only then, you will get an accurate reading. YOU NEED TO DYNO IN 4TH GEAR!!!!!!!!!!! And to let you know, dynoing in 2nd gear "gives" you power. YOU MUST DYNO IN 4TH gear. I seriously find it hard to beleive they let you dyno it in 2nd gear. The 5.4 3V makes 300-310 HP at the flywheel and means you should get somewhere around 230-250 HP to the rear wheels.
You do realize that when you dyno in a gear other than 4 gear in our auto tansmitions you will get a very false reading. When dynoing in 2nd gear you are not at a 1:1 ratio in the transmition. You need to dyno in 4th gear buddy. Then, and only then, you will get an accurate reading. YOU NEED TO DYNO IN 4TH GEAR!!!!!!!!!!! And to let you know, dynoing in 2nd gear "gives" you power. YOU MUST DYNO IN 4TH gear. I seriously find it hard to beleive they let you dyno it in 2nd gear. The 5.4 3V makes 300-310 HP at the flywheel and means you should get somewhere around 230-250 HP to the rear wheels.
Power = Torque * RPM * correction factor. The correction factor is to make the units work. This applies to all gears. I don't see how 2nd gear gives you any power!
Grim
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From: Motor City
Step away from the dyno, sir....
Some things that really screw with the dyno:
Temperature: engine temp *greatly* affects power output. Dyno runs done during different levels of coolant, engine and oil temps will have drastically different results, with the cooler runs producing more power. Some engines, such as the forced induction vehicles, can lose up to 15% of total hp and torque as temps rise. Thus a colder run done after a particular mod will exaggerate gains, if any. Redirecting external cooling fan air can have tangible effects on data, especially when air is concentrated on intercoolers, open air filters, etc.
Gearing: a chassis dyno is susceptible to gearing bias. More power can be produced on a dyno graph by simply running the test car in a lower gear. Dyno operators should pick the trans gear that is closest to a 1:1 ratio to avoid gearing bias. This ratio is 4th gear in most cars.
Atmospheric conditions: all dyno runs should be corrected for atmospheric conditions, typically humidity, barometric pressure, and ambient temperature. Neglecting to correct for these variables can skew data, sometimes purposely.
Some things that really screw with the dyno:
Temperature: engine temp *greatly* affects power output. Dyno runs done during different levels of coolant, engine and oil temps will have drastically different results, with the cooler runs producing more power. Some engines, such as the forced induction vehicles, can lose up to 15% of total hp and torque as temps rise. Thus a colder run done after a particular mod will exaggerate gains, if any. Redirecting external cooling fan air can have tangible effects on data, especially when air is concentrated on intercoolers, open air filters, etc.
Gearing: a chassis dyno is susceptible to gearing bias. More power can be produced on a dyno graph by simply running the test car in a lower gear. Dyno operators should pick the trans gear that is closest to a 1:1 ratio to avoid gearing bias. This ratio is 4th gear in most cars.
Atmospheric conditions: all dyno runs should be corrected for atmospheric conditions, typically humidity, barometric pressure, and ambient temperature. Neglecting to correct for these variables can skew data, sometimes purposely.
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From: Motor City
Oh yeah, did anyone read this article in C&D?
http://www.caranddriver.com/article....&page_number=1
I wonder how the new engine/cpu acts on a dyno w/o airflow...
http://www.caranddriver.com/article....&page_number=1
I wonder how the new engine/cpu acts on a dyno w/o airflow...
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From: Tulsa, O K L A H O M A!
Originally posted by dzervit
Gearing: a chassis dyno is susceptible to gearing bias. More power can be produced on a dyno graph by simply running the test car in a lower gear. Dyno operators should pick the trans gear that is closest to a 1:1 ratio to avoid gearing bias. This ratio is 4th gear in most cars.
Gearing: a chassis dyno is susceptible to gearing bias. More power can be produced on a dyno graph by simply running the test car in a lower gear. Dyno operators should pick the trans gear that is closest to a 1:1 ratio to avoid gearing bias. This ratio is 4th gear in most cars.
Grim
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From: Motor City
Its not that you 'generate' more power, its just that the dyno interprets the data differently.
If you don't belive me, go get your truck dyno'd. Once in 3rd (1:1) and again in 2nd.
I can't explain it, I just know its true.
If you don't belive me, go get your truck dyno'd. Once in 3rd (1:1) and again in 2nd.
I can't explain it, I just know its true.
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Joined: Feb 2004
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From: Sunny Palm Beach Florida
When I had my truck on the dyno they said that they had to run it in 2nd gear because our rev limiters kick in at 5,000 rpm in 2nd gear.
If you did a dyno run in 3rd gear the rev limiter kicks in much sooner at 4,000 RPM.
I agree you should be 1:1 or as close to it when testing. But, until I have the rev limiter removed with a flash I think we are stuck in 2nd gear...
If you did a dyno run in 3rd gear the rev limiter kicks in much sooner at 4,000 RPM.
I agree you should be 1:1 or as close to it when testing. But, until I have the rev limiter removed with a flash I think we are stuck in 2nd gear...
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From: Motor City
Originally posted by rover73
When I had my truck on the dyno they said that they had to run it in 2nd gear because our rev limiters kick in at 5,000 rpm in 2nd gear.
If you did a dyno run in 3rd gear the rev limiter kicks in much sooner at 4,000 RPM.
I agree you should be 1:1 or as close to it when testing. But, until I have the rev limiter removed with a flash I think we are stuck in 2nd gear...
When I had my truck on the dyno they said that they had to run it in 2nd gear because our rev limiters kick in at 5,000 rpm in 2nd gear.
If you did a dyno run in 3rd gear the rev limiter kicks in much sooner at 4,000 RPM.
I agree you should be 1:1 or as close to it when testing. But, until I have the rev limiter removed with a flash I think we are stuck in 2nd gear...
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From: Sunny Palm Beach Florida
Check out my previous post. If you scroll down the page you will find a copy of my print out.
previous post (click here)
previous post (click here)
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From: Lakewood, Southern Cali
OH MY GOD!!!... So sorry. I some how got 4th with a stick and 3rd with an auto mixed up. I am SOOOO sorry. But for sure i knew 2nd gear wasnt correct. Please forgive me for my foolish mistake. I got used to seeing the answer i put for pple dynoing their 5speed v6's over on another message board. Please don't flame me