Traction limited, but not bad anyhow. The 484 run was pretty close to expected, but the 532 was about 90 short. They have a homeade pull down system that exerts downforce primarily. Then they strap to an eye in the vertical strap and pull rearward from there. I ended up partly straightening their over axle (bale hook type) hook, and pulling apart one of the light grade quick hooks on the rearward holding straps.


No tach reference was used so TQ numbers are bogus.


http://www.dieselplace.com/forum/uploads/2FZ_KS_dyno_day.jpg


http://www.dieselplace.com/forum/uploads/KS_dyno_day_2.jpg


Edited by: Diesel Power

wow Mustang really went the extra mile in their readouts/graphs.

wow Mustang really went the extra mile in their readouts/graphs.


They have also been pretty poor in responding to requests for help from K&S. I looked at Mustang and ALMOST bought one, but found it hard to get answers/explanations to my questions, and also found others having trouble geting trucks to "hook up" to the smooth roll set.





K&S spent a lot of time working on installing a down pull strapping system that really does help, but getting Mustang to knurl the rollers AND at a reasonable price is another story...

How does K&S's strapping differ from yours? Your tie down system seemed bullet proof. I am guessing thats where the lower numbers came in (excessive wheels slip). It all comes down to you get what you pay for.

Actually, the 484 was fairly consistent with what I felt it should do. Same setup did 480 Friday on my dyno. Crappy air both days, but likely worse on Friday.





The 532 run setup howver did about 620 Friday.





The Mustang Dyne MD250 is a cradle roll type. 2) 10.7"? rollsets with a semi smooth finish. The only grooving runs around the rollers. Tires are forced to bend around 2 smaller diameter rollers. You can get by with only strapping rearward on this type. K&S added a pair of hooks that loop over the axle tube and dun down to a pivot point, then rearward for access. Basically 2x what Mustang shows below. The result looks like this:


_____? with the addition of another strap pulling fronm the midpoint of the ? This seems to hold pretty well up to mid 400's but it's hard to tell how much waste there is with the downforce loading the tires and creating excessive deflection.


Dyno:


http://www.mustangdyne.com/ChassisDyno/md250.htm


Pull down:


http://www.mustangdyne.com/Options/Pulldown.htm





My Superflow is a single (actually dual) drum type with a 42" diameter knurled rollset. I strap forward, backward, AND side to side as any strap failure will alow the vehicle to leave the building.





Here's a page from Superflow showing some dyno runs. The Outlaw is pretty wild. No driver, and it needs some additional tiedowns to hold the front down better:





http://www.superflow.com/autodyn/see.html

John,


How are they getting a sprint car to work on the Dyno? A sprint has no clutch. It uses a coupler in the rear end to link the lower shaft. With no starter makes it about impossible. Can the Superflow can spin the drums to start the car?

John, i have had the same problems on a mustang dyno.... the last even everyone 500 RWHP or Better (verified on other dynos) were slipping into the 420-490 category.... mustand really needs a better tie down solution. 5 short years ago when 500 RWHP was an amazin achievement they worked fine, but now that 500+ is quite common it really needs an update!

Not sure how they do it, but everything is remote controlled.

Hey John,


Maybe you can answer a couple of questions for me.


Did or does K&S change the weight for each truck? If so, how much does error in weight change the output? Also, the 21hp at 50 mph. Mustang told me this was "road load" numbers based on DOT research that is used. This number is also used to calculate the output but I don't know what impact the error rate would have on the final output.


The problem I have seen is the torque numbers just seem to high for me in too many cases. On your dyno, you show 505hp/970tq which is very close to what Brandon reads on my dyno. But on the Mustang you went from 505hp to 484hp yet tq went from 970 to 1246. I realize my dynojet can in some cases miss some tq if you have a laggy set-up but from what I keep seeing, I am loosing faith in Mustangs ability to be accurate.


I have had to explain to a 7.3 owner that even though he had a 260+hp dyno run off a Mustang that there was no way he was making the nearly 1100 tq it said. On my dyno he read nearly identicle hp with tq in the 600's.


I'd like to hear your opinions on what you have seen.

Hey John,


Maybe you can answer a couple of questions for me.


Did or does K&S change the weight for each truck? If so, how much does error in weight change the output? Also, the 21hp at 50 mph. Mustang told me this was "road load" numbers based on DOT research that is used. This number is also used to calculate the output but I don't know what impact the error rate would have on the final output.


The problem I have seen is the torque numbers just seem to high for me in too many cases. On your dyno, you show 505hp/970tq which is very close to what Brandon reads on my dyno. But on the Mustang you went from 505hp to 484hp yet tq went from 970 to 1246. I realize my dynojet can in some cases miss some tq if you have a laggy set-up but from what I keep seeing, I am loosing faith in Mustangs ability to be accurate.


I have had to explain to a 7.3 owner that even though he had a 260+hp dyno run off a Mustang that there was no way he was making the nearly 1100 tq it said. On my dyno he read nearly identicle hp with tq in the 600's.


I'd like to hear your opinions on what you have seen.





"No tach reference was used so TQ numbers are bogus." from JK's first post. The torque figures on Mustang plots do seem to be all over the board though.

READ DAVID READ... http://www.dieselplace.com/forum/smileys/Ermm.gif





Thanks Brandon...

One thing that needs to be watched is the sweep times on a Mustang dyno, or for that matter any load controlled dyno. I've run enough on all types of dynos and each has there own way of doing things. On a Mustang I've found if you start with a sweep rate of 5 sec and change in steps of 5 sec you will find the power output changes. The trick is to keep changeing it until the output nolonger changes. Doing a Dmax in 4th gear typically needs about a 25 sec sweep rate for the numbers to settle down and it becomes very repeatable. This is running the engine from 1200 rpm to 3700 rpm.

Here is the plot from the setup test we did when trying out their hold down system. We used the optic tach for this test. The tires turn to gum on the Mustang, and peak torque is never really measured. If the peak is lopped off, of course, the rest of the curve is somewhat questionable as well. This test was done using a 12 second sweep rate as that is what the dyno day setup was to be. This is also the same setup that ran the 484HP numbers. I haven't played with the Mustang software, but one way a guy can do it w/o the optic tach and get a VAGUELY reasonable number is to match RPM to roll speed. This of course only works if the rollers bite. http://www.dieselplace.com/forum/uploads/KS_dyno_setup.jpg











When I test on my Superflow, I pull to the start speed, floor the pedal and the dyno holds. When EGT stabilizes reasonably, I push the Accel button and the test begins. I use 12 seconds in most cases as this is very consistent if I stabilize to the same point. Refer to the Xcelerator thread where I showed 3 tuners on chart. The only real difference in two of the runs is that I may not have stabilized to quite the exact same point.