View Single Post
Old 11-04-2013, 05:43 AM   #7 (permalink)
euromodder
Master EcoModder
 
euromodder's Avatar
 
Join Date: Jul 2010
Location: Belgium
Posts: 4,683

The SCUD - '15 Fiat Scudo L2
Thanks: 178
Thanked 652 Times in 516 Posts
Welcome to ecomodder.

Looks like you've made a good start already

Quote:
Originally Posted by hliew88 View Post
I want to be able to hit 30mpg combined sometime, so I'd like some suggestions for CHEAP mods.
You've already gone a good way regarding mods, and mpg.

Quote:
Coroplast sheet under the spare tire - otherwise rear bumper + hitch = parachute. Could I make a diffuser here?
Looks like you already have a diffuser there, as the aft belly pan section is angled up quite a bit.

It's a vehicle with a (nearly) horizontal roofline, so a diffuser won't help there - and by itself may make the drag even worse.
Though it's helping the belly pan to work, and eliminating the aft parachute effect which both help your mpg, the diffuser is possibly reducing some of what you gained.

Old aerodynamics research showed diffusor angles should generally be rather small for drag reduction, like 2-5°, and 0° on horizontal roof lines (old station wagon style).


Quote:
Rear side fairings made from transparent plastic sheets (see pics). Holding up alright, without looking too silly.
Do you see much effect of these ?

At best, I'd expect some cleaner separation of the air, which you might see as changes to dust and rain accumulation on the rear end, though it may not be apparent in your day-to-day fuel consumption.


Quote:
Front air dam made by curving 2 strips of some patio siding.
It doesn't seem to be helping my mpg though... explanations?
It's a bit too wide.
Air dams (and bumpers) push out the air a bit further than where they end.
This increases the apparent frontal area - even though they are within the original vehicle frontal area.

It's OK if the airdam ends a few inches inboard.

Same with your rear-wheel deflectors.
They seem to be positioned too far outboard.
Unless you add side skirts between the wheels, the air will flow out to the sides @ about a 15° angle - though a diffuser would suck the air more to the rear .

The position and angle of the deflectors in front of the rear wheels needs to be chosen in relation to the air that hits them.
They can be extended aft as vertical strakes on the inside of the rear wheels, separating dirty (wheel side) and clean (belly pan) air, the strakes can then be carried further aft as a diffuser side plate and/or inboard side of a rear wheel fairing.

Quote:
I haven't done anything to the engine, so I need some suggestions there!
You've already done some mods there : the grille block and belly pan keep in the heat better, so it'd warm up quicker.

Warm air intake.
Keeping the air filter clean also helps - with OEM often being more efficient than K&N style filters.
Pre-warming coolant or oil.
Engine blanket - or some simple cardboard as some ecomodders are using.


Quote:
Engine is happiest between 33-37 mph and 51-57 mph - I can get about 33mpg on a flat road
So that's where you want to be.
Around 55mph is a nice speed for many cars as far as mpg goes.

Quote:
Sucks that this is an auto tranny though...
You can always correct that in your next car

Buying a fuel efficient car is the best mod to start with.
I'm surprised it's still not high up on the ecomodder Mods & Tips pages

The latest automatics - like the ZF 8-speed box (BMW / Jaguar / LR) - are good for FE though.


Quote:
I get a lot of wind noise around the A-pillars - does anyone have experience with turbulator tape or similar to modify airflow around there?
I do

It actually works, even when using dimple tape - which is only a series of heat-formed holes made into a sturdy tape, making what looks like very small volcanoes, the holes being the crater

Doing it again I'd use zig-zag tape rather than dimpled tape.

I put dimple tape along the A-pillar, quite close to the windshield (before the air is making it around the corner to the sides) and on the mirrors.

The tape, though ridiculously thin, audibly reduced the A-pillar noise - very common on this car series .

It altered the air flow over the side windows enough to affect the flow pattern of raindrops that'd get onto it, then stay on the upper front half of the side window and block vision.
With the dimple tape, the raindrops became near-horizontal streaks and got carried aft with the airflow, restoring vision.

Pics are restored in this message :
http://ecomodder.com/forum/showthrea...tml#post323190

Quote:
How about at the back (around the trunk)?
It's pretty useless at the back as I found out.
See the link above for what I did @ the back end.

Tape is simply too low to effectively alter the airflow here.
The boundary layer will be too thick.
I never saw any change in flow (rain, dust accumulation) pattern there - let alone in mpg
__________________
Strayed to the Dark Diesel Side

  Reply With Quote