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Wheel Slip, PID, RPM sensor or strapping techniques  

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(@rtattam)
Member Customer

Hi Guys,

Wondering if anyone can help?

I have an old Vane VP950 chassis dyno with a Telma cc135 that I have updated using Yourdyno and a Sportdevices PWS3.2.

At the moment I'm struggling to get traction on the dyno with anything that has a fairly steep torque curve, the only cars that I have had on it are in the area of 300hp/300ftlbs and fairly light (datsuns).

Being a novice I'm not sure if its my PID settings, My strapping techniques or something going on with my rpm signal.

I'm really happy with everything at steady state and I can access all relevant areas of the map that I need to, it all seems to go awry when trying any of the PID related sweep functions.

I'll attach my settings and some recent tests at various PID settings.

If someone could take a quick look and let me know if there's something glaringly obvious that I've overlooked it would be greatly appreciated.

Cheers,

Rich.

This topic was modified 1 week ago by Datbeast
Quote
Posted : 14/09/2020 10:47 am
(@rtattam)
Member Customer

https://drive.google.com/file/d/1hbLI9DBikD4t9hSfEVFO2tGfPsHl7lz_/view?usp=sharing

 

Sorry I couldn't find the attach file button so I linked it this way.

Cheers,

Rich.

ReplyQuote
Posted : 14/09/2020 12:36 pm
(@boz-race-engines)
Member

it is all about how you tie the car down, alot of dynos dont have a proper vertical pull down system, if you look at dyno dynamics on youtube and you will see their rear bar pull down system, i went to that type of system and no more issues

ReplyQuote
Posted : 15/09/2020 4:36 am
(@mach_1)
Member

I 2nd what boz race engines said about the way you strap the vehicle to the dyno. Did that back in  year 1995 no issues with big horsepower cars.

For chassis dynos DD's tie_down system works the best.

I have shared the information on here before easy to find do a few searches on here.

 

 

This post was modified 1 week ago by Mach_1
ReplyQuote
Posted : 15/09/2020 11:05 am
(@rtattam)
Member Customer

Cheers for your replies.

I'm in the process of doing something similar to DD's method that you mention at the moment.

Any advice on strapping down decent powered IRS cars? This is also an issue for me I believe.

One more thing, can someone please shed some light on where the "attach file" button is on this forum?

TIA

Rich

ReplyQuote
Posted : 15/09/2020 11:17 am
(@mach_1)
Member
(@admin)
Member Admin

For wheel spin a (counter intuitive) trick is to use WD40 on the tires. Still need good tie down though. 

ReplyQuote
Posted : 15/09/2020 10:26 pm
(@mach_1)
Member

WD40 = cheap PJ1 TrackBite sticky stuff

Select " chooce file " is what i use on my mobile telephone your display might be different.

IRS   is a bit tricker .... i have made various bolt_on brackets for the range of vehicles i have tested over the many years , only use it on high horsepower  vehicles. Still utilising the DD's tie down pull down method.

IRS rear ends are a pain in the but!  BUT still possible to control the traction on the rollers.

This post was modified 1 week ago by Mach_1
ReplyQuote
Posted : 16/09/2020 1:20 am
(@rtattam)
Member Customer

Thanks to everyone for their input.

I will try a few things as suggested and report back.

Thanks again

 

ReplyQuote
Posted : 18/09/2020 4:42 am
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