Projects and Updates - Page 4 of 4 - Promotive Engineering

GT2 Update

April 4, 2015 by Promotive Leave a Comment

The The GT2 shell is back from the sandblasters! I have finished all of the major fabrication at last.

It doesn’t look like much at the moment but after a splash of paint and the composite panels are bolted or bonded on, it might actually look like the Porsche it was. Just a lot lighter, stiffer with better suspension geometry!

The new engine is going back together at the moment and should be on the dyno in the coming months. As in its previous incarnation, the engine is controlled by a Motec with one of my lightweight tefzel looms which saves just over 60kg compared to the factory loom and all of the various ECUs! This engine has some trick bits inside with a couple of Borg Warner turbos that I have found to be the performing turbos at the moment. More on that later…

Interestingly (to me anyway!) the chemists at ETS Race Fuels in France have recommended ESR GC4 as the fuel that has the best burn characteristics to suit this engine spec. It will be interesting to do another fuel comparison on the dyno. The gains by switching to the right fuels so far have been nothing short of amazing!

I can’t wait!

Liquid Power!

March 4, 2015 by Promotive Leave a Comment

I have to say that I am pretty chuffed with the ol’ twin turbo Canyonerro. It isn’t a bad workshop hack. It could be improved with a set of DS3000 brake pads so it stops from speed more than twice, and the 22inch wheels make what is normally a really capable 4wd, utterly useless and barely able to traverse an average sized pothole without total destruction to the rim and tyre.

I want more power but every time I start plan on giving it a bit more boost and a tune, I can’t help thinking that getting more than 350kms to a tank of fuel would also be nice. It is actually becoming a bit embarrassing – the girl at the petrol station down the road thinks I am a bit keen on her because I am visiting so often! To avoid my second visit in a week, I decided I would see what happens if I filled up with some ETS ExtraMax race fuel…

Well, I did actually know what would happen. The Bosch Me7 engine management in these beasts might be getting a bit antiquated compared to the latest tech, but it was happy to keep winding in the spark and fuel until the dyno showed about a 30hp gain at the wheels! To be fair, the actual horsepower number falsely showed a bit more than 42hp but there was a spike at the end of the run each time as the traction control woke up and tried to outsmart the dyno. The airbag suspension also decided it need to take action too. Watching the electronics try and fight the dyno was like watching 50 Shades of Grey with your mum. Not good. Porsches just don’t like to be tied down and abused… I will upload the graphs soon.

One thing that is actually amazing is how much better the throttle response was on the way home. The exit from corners was addictive!

Unfortunately it wasn’t all good news. After driving it home from the dyno I realised that I am like a fat boy with cake. I need more. More power in this case, but more cake in my life would be good too.

3D printing – A waste of time?

February 27, 2015 by Promotive Leave a Comment

Well, I don’t feel so special now. I was so happy with my little 3D printer and then Monash University go and print something close to my heart – a working jet engine! (link here) Damn – that makes my printer look like a dinky toy. Oh that’s right – it is!

I have been pretty sceptical that cheap 3D printers are even slightly useful. That is until I ordered one out of frustration.

A while ago I decided it would be a good idea to modernise my mighty Lycoming 540 engine for the aerobatic plane to give it a bit more vertical penetration. That included Motec M1 engine management, tuned length manifolds and exhaust, custom pistons and cam etc. To really complicate the project – I thought it would be a good idea to totally redesign the valvetrain. Just because I can doesn’t mean I should!

The CAD design was obviously the easy part and a lot of fun trying to optimise such an archaic design. It didn’t take long to draw up some roller rockers, solid lifters, tapered pushrods, valves and guides etc. The problems started when it came to validating the design. There is no substitute for a working prototype to test the geometry but trying to find a spare moment to fire up the CNC to make a test rocker pushed the project onto the backburner for way, way too long. Heck – I was getting worried that the earth was going to run out of fuel before I found the time.

Enter the 3D printer…

I am really flabbergasted how much time it has saved. Quite frankly, I feel a bit silly that I didn’t already have one! Within fifteen minutes of it arriving, it was printing prototype number one. Within that first day it had printed the prototype number five, the final rocker which allowed me to get the valves and guides ordered. No wasted time trying to work out how to hold a billet of aluminium in the CNC, no swarf, no mess, and no time wasted when I could be working on customer cars. It also saved me from ordering the wrong length valve due to a measurement probe offset error that I probably wouldn’t have picked up if I didn’t have a little plastic printed valve to compare to a Lycoming factory one. That error would have cost me more than the printer and put me in a really bad mood for a really long time.

I think this printer and I are going to get along just fine. I needed a 90 degree backshell for a wiring loom I was making yesterday. I couldn’t find one commercially available. No problem. It didn’t take long to whip up a drawing and send it to the printer. The result was printed in ABS plastic which is the same material as the one that came with the plug.

Now I just need a 3D scanner so I can make a bobble head to stick on the dash of my car…

Oh, and now I need to find the time to go and make the optimised roller rockers on the CNC.