Another Dyno Thread - Oh No!
Discussion
Spent Friday pm at a new local Dyno Dynamics Dyno. They normally do Scoobies but were interested in our big Chev V8's, looking to do some Northern Dyno days next year. So we took a couple of cars around for them to play with.
Was devastated to find out there were no RW torque graphs, only FW figures!!!
I asked why not and after a conversation with DD, the owner told me the new software did not include that facility as the older stuff was open to abuse.
He didn't elaborate on that so I wondered if the experts on here could expand as to why that would be?
We also had a problem trying to get some numbers on the ute, the new stall convertor was having none of it. Efilive Bi Di control could not hold 3rd and it just kept kicking down to 2nd. Bloody auto's!
Was devastated to find out there were no RW torque graphs, only FW figures!!!
I asked why not and after a conversation with DD, the owner told me the new software did not include that facility as the older stuff was open to abuse.
He didn't elaborate on that so I wondered if the experts on here could expand as to why that would be?
We also had a problem trying to get some numbers on the ute, the new stall convertor was having none of it. Efilive Bi Di control could not hold 3rd and it just kept kicking down to 2nd. Bloody auto's!
I dont understand. Its being measured at the rear!?
How can they say taking that number and mutating it into a flywheel number is more accurate!
Sounds like a pile of s
t to me.
I know if you get the gearing wrong the dyno will drop the torque curve in the wrong place on the graph.
How did you try to hold it in efi? Scan tool, DVT and from there? Did you enable DVT mode first?
From Car and Driver
"There's no really accurate way to get engine horsepower from a chassis dyno," says Matt Harwood, marketing coordinator for Mustang Dynamometer, a major supplier of chassis dynos in Twinsburg, Ohio. Some tuners use the so-called 15/20 rule, which assumes a 15-percent driveline loss for manual transmissions and 20 percent for automatics. But, says Harwood, "I've seen losses as high as 35 percent." So unless it's printed in the brochure or was measured on a true engine dyno or by a tuner with tons of experience with your particular brand of car, any flywheel horsepower number quoted by a hot rodder under the shade tree is most likely just a calculated guess.”
And from Hotrod Magazine:
The Truth: Are Chassis Dynos Legit? What you need to know about getting your car tested
“There is really no way to measure, predict, or otherwise determine engine flywheel power from a chassis-dyno test with any repeatable certainly.”
How can they say taking that number and mutating it into a flywheel number is more accurate!
Sounds like a pile of s
t to me.I know if you get the gearing wrong the dyno will drop the torque curve in the wrong place on the graph.
How did you try to hold it in efi? Scan tool, DVT and from there? Did you enable DVT mode first?
From Car and Driver
"There's no really accurate way to get engine horsepower from a chassis dyno," says Matt Harwood, marketing coordinator for Mustang Dynamometer, a major supplier of chassis dynos in Twinsburg, Ohio. Some tuners use the so-called 15/20 rule, which assumes a 15-percent driveline loss for manual transmissions and 20 percent for automatics. But, says Harwood, "I've seen losses as high as 35 percent." So unless it's printed in the brochure or was measured on a true engine dyno or by a tuner with tons of experience with your particular brand of car, any flywheel horsepower number quoted by a hot rodder under the shade tree is most likely just a calculated guess.”
And from Hotrod Magazine:
The Truth: Are Chassis Dynos Legit? What you need to know about getting your car tested
“There is really no way to measure, predict, or otherwise determine engine flywheel power from a chassis-dyno test with any repeatable certainly.”
They do rwhp figures, but can't get a printout of RWtorque???????????????????????
I asked for RW hp torque on the same graph, and the owner (very nice chap BTW) phoned DD who said it was not done on the latest version.
Superb, brand new dyno, with motor driven, extendable bed (pics coming) They also don't do bonnet up runs because he reckons the fan he has would fold them back.
Used DVT but got an error message up on a red bar. Joe car is helping.
I asked for RW hp torque on the same graph, and the owner (very nice chap BTW) phoned DD who said it was not done on the latest version.
Superb, brand new dyno, with motor driven, extendable bed (pics coming) They also don't do bonnet up runs because he reckons the fan he has would fold them back.
Used DVT but got an error message up on a red bar. Joe car is helping.
Edited by MyM8V8 on Sunday 6th September 21:44
That sounds like sewage. rwhp numbers are mathematically related to rwtq numbers you can just dig the calculator out and figure them out.
hp=(torque*rpm)/5252
So that sounds like someone is talking total bks and should be shot.
If they can graph rwhp then they know rwtq. Maybe the guy just couldnt be bothered.
hp=(torque*rpm)/5252
So that sounds like someone is talking total b
ks and should be shot.If they can graph rwhp then they know rwtq. Maybe the guy just couldnt be bothered.
Vixpy1 said:
The new software does rw torque, and rw hp. In fact it will do exactly the same graphs as the old sofware, just in a different style
Just had a conversation with someone in the know and it appears the problem is solved. DD have told them how its' done. The kit is brand new and I think they are getting used to it all.That's good because although I like Charlie, It's a long drag down there when I have one 2 minutes round the corner!
I'll do a bit more work with them and we can now look forward to a Northern Dyno Day next year to compliment SRR.
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