Road Dyno

[Heuer]

Here is a great little gadget for all those who want to tune or upgrade their car's performance. The GAA Road Dyno http://www.roadtune.co.uk/acatalog/Road ... ducts.html costs £75 and gives very accurate measurement of a car's on-road BHP and torque throughout the rev range. Included in the kit is the Road Dyno box, software, HT clamp, connecting lead and serial PC connector.


Connect the HT clamp around one plug lead, run the (ample) cable from the bonnet to the car interior (I ran mine between the bonnet seal and in through the passenger window) and plug in the Road Dyno and switch to 'on'. Find a flat and empty stretch of road, switch the Road Dyno to 'record', gently get the car rolling and into second gear at about 1,000 rpm and floor the accelerator up to maximum revs. Switch the Road Dyno back to 'on'. You can do multiple runs as each run will be stored separately provided you do not switch it to off. Connect the Road Dyno to a PC with the supplied serial cable (I attached a Prolific Serial to USB convertor) and start the RD Processor programme. This will allow you to download the files and save to your PC.



Run the Road Dyno software, pick your file and you can then add the various parameters for your car.



By clicking the 'Process' button the software will graph your results.



So how accurate are the results? Here is a rolling road graph done a few weeks ago on my car (before my carb rebuild):



The differences are the rolling road graph was based on power at the wheels whereas Road Dyno calculates the power at the flywheel. Also, due to the high gearing on my car I had to use 1,500 rpm to start the test so I have a much sharper ramp up of power. The Road Dyno graph is with the new carbs. A few more runs, and a bit of practice I have no doubt I could get a better graph. The graph below shows the same run after I asked Road Dyno to take out transmission losses so giving me 'at the wheels' results.



The max BHP and torque are very similar proving the Road Dyno is a very accurate little device for the money. Its main use is in doing comparative runs after setting carbs, timing, upgrades or even different fuel types. In my case both Road Dyno and the rolling road prove I have a torque dip around 2,500 rpm which I intend to address this week with the help of a Classicfabs manifold. I will have a before and after graph to see what gains, if any, are available. More on that later. Not bad for £75+VAT considering a rolling road run costs £135 a time.

Note: Yes, the coefficient of drag of an S1 E-Type OTS (hood down) is indeed 0.55. S1 FHC = 0.5. A contemporary Porsche 911 is 0.327. So much for aerodynamics!

Road-Dyno software and instructions: https://www.dropbox.com/s/kgq66l8tfygv2 ... o.zip?dl=1

[Woolfi]

Is this company still existing ?
Wher can I buy this road dyno ?
Regards Wolfgang Gatza

[Heuer]

Wolfgang

Unfortunately the units are no longer available. They were produced by GAA in Scotland and the software by DDI in America. The latter is still contactable http://www.ddisoftware.com/ and Mike Haney, the programmer, has six GAA data units for his own evaluation and bug fixing. Several people have contacted him (including Ray Livingston) with a view to buying but he won't sell. I have been pushing Ray to make a unit and put him in touch with the software developer but nothing has come of it as yet. Ray suggests the unit would be fairly simple to make - basically an accelerometer and ignition pulse analyser - as the software does the work. Currently the software is sold as TT Dyno: http://ddisoftware.com/tech/tt-dyno/?PH ... 7iqs95g200

I understand there are various iPhone and Android apps available which attempt to do the same thing with varying degrees of success.

Personally I think the Road-Dyno is the most valuable thing you can own if you are tinkering with a car and I would love to see it available again in one form or another. They cost ?75 originally - bargain! If you know someone who can produce electronic units such as these DDI will be happy to supply the software.

[Woolfi]

http://www.gtechpro.com/ss_fanatic.html

G-tech is offering similar devices, but for a much higher price.

Regards Wolfgang Gatza

[abowie]

Woolfi any idea how the Gtech device measures RPM and horsepower?

[JEP41]

Hi All,

I have been using the Road Dyno for a couple of years now, I purchased from Rob Beere Racing. It is an excellent product for checking and setting up my Lightweight Replica engine, after the initial setup on Pete Baldwins rolling road in Wimpole Cambridgeshire. :D

[Heuer]

Woolfi any idea how the Gtech device measures RPM and horsepower?

Andrew

It does not, it gets its information via GPS. There are lots of systems out there but they usually rely on plugging into the car ECU so not much help in an E-Type. The GAA device has a link to the ignition pulses and measures the rate of acceleration of those pulses plus rpm. The RoadDyno software relies on the user inputting the various variables - tyre circumference, weight, frontal area, gear ratios etc - and it then works out the bhp and torque.

I have searched high and low for an alternative to Road Dyno but none exists as far as I can see. Limited market it seems because modern cars have the OBC socket which gives the required metrics.

[AVR]

Does anybody by any chance still have the software and instructions for this, I purchased one of these units 10 years ago and have the original floppy discs (x2) but my pc is unable to recognise the second disc.

[Heuer]

Here you go:
https://www.dropbox.com/s/kgq66l8tfygv2 ... o.zip?dl=1

Files from both discs and setup.exe.

[chrisfell]

Does this device give Jaguar horsepower or real world horsepower?

[RocLobsta]

I have one of these new in the box complete with CD's, it's never been taken out of it's packing. Found this thread while googling for its best uses.

Perfect for these cars I'm lead to believe.

[Heuer]

Feel free to advertise it in our Wanted/For Sale section. Fun device.

[Jaglex]

The old GTech Pro/RR takes the RPM from the signal the ignition sends into the electrical system of the car. Big part of this signal is usually eliminated by a condenser to avoid disturbances of the radio, but there must be something remaining, that is identified by the Gtech. The operation manual says:

Since every vehicle has a unique electronic “RPM signature,”
the G-tech must learn the RPM signature at different RPM
levels on your particular vehicle before it can measure and
record RPM.

I tried it and I have to say: it works. The GTech displays the same RPM as the meter I used to train the GTech.

The later GTech-Models take the signal by a separate line from either the ignition coil or the OBDII.

Happy tuning,
Alex

[Tom W]

I’ve just bought myself a 2nd hand road dyno. I can’t get it to connect to my laptop though. I have an old laptop running XP, and the software with the dyno runs fine on that. I have bought a USB to Serial lead, and after some faffing with drivers, the computer now recognises then lead and has assigned it a COM number. When I start the software to download the data from the box, it recognises the COM port, but when I click Link, it just hangs. Does the box need to turned on or off when the link is established? Neither seems to make any difference and the instructions don’t say. How long should it take to connect?

Edit. I’ve now managed to get it to search, but no connection. Road dyno not found. The prompt then says it has to be on.

[Heuer]

Does the lead have a Prolific PL series chip in it as no other chip works with Road Dyno. I have fixed the link to the Road Dyno setup and instructions and they may help. https://www.dropbox.com/s/kgq66l8tfygv2 ... o.zip?dl=1

[Tom W]

I have no idea. It was the cheapest lead off eBay. I assume it’s either a prolific chip, or one of the Chinese copies, as it was only after downloading a prolific driver that I managed to get it to work. I had to find an old driver as the most up to date ones caused problems. I seem to have gone backwards again now as the programme hangs again every time I try it. Not sure what I’d done differently when I actually managed to get the software to search for the road dyno.

[Tom W]

I’ve found a bit of software that checks what chip’s in the lead. It says PL-2303 XA/HXA.

[Heuer]

You could try a different laptop. You can download the software from my link and it will run on Win7 and Win10. This is the type of Prolific lead I use:

https://www.ebay.co.uk/itm/Prolific-PL- ... SwIk9aceOX

You could try this one:

I seem to recall I had a few problems when I bought my Road Dyno and spoke to the developer. He said to avoid cheap adapters because they have knock-off chips in them and will cause you angst. Seems we both fell into that trap! With the correct serial to USB cable it connects immediately.

[Tom W]

Progress. I’ve found an old laptop with a serial port. Connected directly it seems to be working now, except this laptop isn’t connected to the web, so I might still try a better lead so I can upload the graphs more easily.

Early results seem similar to the rolling road session I had, though it’s obviously very dependent on the data I put in. I’ve also fiddled with the car again between the rolling road run and buying the road dyno, so it is unlikely to be like for like.

It will be very useful for comparing the before and after effects of tuning (fiddling).

First run shows 281 lb/ft@3700rpm and 226 hp @ 4800 rpm.
The rolling road showed 294 lb/ft@3200rpm and 216bhp @ 4000rpm.

[Heuer]

Well done Tom! Extra kudos for finding a computer with a serial port!