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Hey guys, I'm new to the chassis dyno thing and have a couple of questions....

Last week we put my turbo car on a Superflow dyno to do some upper boost tuning. The Superflow uses knurled rollers and I ran my ET Street tires (33 x 18.5) at 20 PSI because I was told that they should be run at a higher PSI. I was getting some tire slippage (1500+ HP).

What PSI do you run?

Next question, I am going to try the Dynomax dyno challenge and have a small problem.

The Dynojet dyno uses a roller drum spread of 29.5 inches and my rear tires are 28 inches inside. Can I just let the tires hang over ¾ of an inch on the inside? I do have a set of MT soft compound Sportsman Pro’s that will give me a 29” spread that I can fit wheel spacers to yield 30”.

So….should I

A) Just let the ET Street’s hang over on the inside of the roller.
B) Switch to the Sportsman Pro’s and not hang over the roller (may give more slippage).

Also, are the Dynojet’s rollers knurled?

Thanks for any help!
 

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X275!
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Yes Dynojet roller are knurled. Letting the tires hang over that much should be fine. If it is a big wheel Dynojet (48" roller I believe), you should have less problems with tire slippage.
 

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X275!
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20 psi sounds a little high, but if the width of the tread is on the roller you should be fine. Remember that the straps are pulling the car/tire down onto the dyno which should help flatten the tread, even with higher than normal air pressures. Personally, I like to run the pressures a little high because it helps to keep the car more stable on the dyno.
 

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The higher the psi you run, the higher the HP you will get on the dyno.

If you can do it without slipping, run 28 psi.

But you'll likely need to start dropping psi until you can eliminate slippage. A good dyno operator will get your car strapped down so tightly on the drums that you shouldn't have much trouble.
 

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They spray the shit out of the rollers with belt dressing so much you come hear the tires sticking to it.. Just let Andy (the owner of the dyno) know what kind of numbers you are expecting.. Good luck....

1642 last hear was not spinning
 
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