Project EconoPolo (aeromodding a VW)

[Grant-53]

I found two sites with pictures on homemade radiator ducting.
forums.macrumors.com>Mac Community>Community Discussion
ecomodder,Aerodynamics, BMW cooling duct, fabrio, 3-31-2008

[viio]

Not sure what to do with that first one, but I google the second and found the BMW exit duct which looks good but it's a bit extreme for my little polo and it isn't an air straightener.

[euromodder]

Originally Posted by viio

Just did a little Google reading on flow separation (as I didn't know what it was lol). It sounds like there would be a case for a rear tray that actually extends past the rear of the bumper at the bottom, does that sound right?

It'd provide a ridge for the air to cleanly separate from.


I've been looking at your fuel consumption.
With all the work done on it, I'm surprised it's still so high (or low in mpg)

My sister has the 1.4 TDi in a Fabia, runs under 4L/100km (better than 71 mpg UK or 59 mpg US) without much of a problem.

Actually my nephew managed 4L/100km while he was learning to drive - no pun intended, just saying.
They want them to shift early at the exam, so that's what he did.
No fancy things like highly inflated tyres, weight reduction, aero cleanup, let alone coasting (which would be an instant fail at the test).


It's not the weight carried around the motorway - it doesn't really matter there. It does matter in town though.
At (legal) UK motorway speeds, or a tad lower, it should do nicely.

[viio]

Yeah I have been wondering about the overall consumption. When I got the car it was doing 51 mpg UK, and I have to work HARD now to get it doing 65mpg now that it's aeromodded. I wonder if there's something wrong with the engine, but I've got no idea where to start. I just serviced it about a month ago - new air fuel and oil filter & new brakes, but I wonder if glow plugs could affect fuel economy if they're tired?

[kingsway]

It's easy to get carried away with the fun of aeromodding etc - but are you sure you've covered the basics?

I thought I was getting very good fuel consumption, but yesterday, whent he car went in for it's annual inspection (MOT) I got an 'advisory' to say the nearside rear wheel was dragging! Took the caliper off when I got home, cleaned up all the metal rubbing surfaces and applied some Copper-slip and it made the world of difference - the wheel now spins very easily. Its the winter salt on the roads that inevitably causes corrosion and minor problems.

You say you had the brakes done recently - but it might be worth just jacking up each corner of the car and checking that the wheels all spin freely?

I got 55mph (IMP) on the last tank - but it would have been higher had I realised earlier that I had a brake problem (and my car is a lot bigger than yours, and is mostly driven by learner drivers!)

[viio]

Yeah earlier in the post I got the rear brakes done as they were totally trashed:


I can hear my front discs rubbing a bit when I'm driving along so they are next. I'll jack the front wheels at the weekend and see how bad they are.

Word of warning on the copper slip though, apparently it wreaks havoc with ABS sensors so some places are switching to using lithium grease instead and wouldn't even put copper on wheel nuts due to proximity.

[kingsway]

Originally Posted by viio

Word of warning on the copper slip though, apparently it wreaks havoc with ABS sensors so some places are switching to using lithium grease instead and wouldn't even put copper on wheel nuts due to proximity.

That's good to know - hadn't heard that before. Maybe some of them are silicon based. I know silicon can creep a long way and cause big electrical problems....

I know in some of the car magazines they show big amounts of it being splashed around, which has always worried me a bit. I use just a light smear so that it is not enough to go anywhere other than where I want it.

Some cars have an automatic mechanism for adjusting the hand-brake tension - something like that could perhaps mean the adjustment suddenly becomes enough that pads are rubbing excessively?

What about wheel alignment? - excess 'toe' could also mean a bit of extra rolling resistance...

It's all too easy to overlook the less glamorous and greasy bits underneath!

[viio]

The car is getting lowered next weekend so after that I'll be putting it in to get aligned with lasers and magic. It's something I normally do any time I buy a new car cos you never know what mess its in. I've been putting it off though cos I knew I'd be changing the suspension springs.

[kingsway]

Are you fitting coil-overs? I see some are available for my car quite cheaply. I may be tempted later in the year. ( I like the idea of being able to change the ride-height) - although I can sometimes hear my front bumper scrape if I go over a speed-bump too quickly...

I see you are using the 'Torque' app. Does it work okay with your car??? I've had problems with the Golf and bought an Ultraguage instead. I know the Torque developer was talking about working on a VW protocol ....

[viio]

I've just gone for apex lowering springs (can't afford full coilovers). A straightforward drop of 30-40mm, using progressive springs rather than linear so I don't lose too much ride comfort. It's going to end up lifted again though cos I'm planning to put tyres on that are almost 2 inches extra diameter!