Big bumper or small? (VW Golf Mk2)

[G2TDI]

Ok grt thanks for the input I guess we know now how the Seat one differs!

[G2TDI]

Ok so for a while I gave up on this idea, why? Well one thing being too many cars as it is. Another thing is it is getting harder and harder to find a good candidate (car) it would be one that would need any body work not dents nor rust. Something minor I don't care about but I wouldn't want to fix the body as I'd want to spend time on the under the hood and other eco ideas

Anyhow the next generation mk3 has become one of the cheapest for now, I guess they are now in the "not-new-enough-not-old-enough" category. So I dug up one of my old books and found it to contain the weight *and* drag coefficients.

So here is a comparison of Mk1-Mk2:

Mk1 Weight 1918 lbs (870 Kg) Drag: 0.42
Mk2 Weight 2026 lbs (920 Kg) Drag: 0.34
Mk3 Weight 2387 lbs (1084 Kg) Drag: 0.30

Yes these numbers may vary a bit based on model but I chose Diesel and 2 (aka 3) door versions wherever I found it.

Now in the general picture using the Aerodynamic & rolling resistance, power & MPG calculator - EcoModder.com calculator I come up with numbers indicating that the Mk3 generation would be even better despite it's heavier weight. Now keep in mind these are STOCK weights, I would dump most of the interior and certain other things like spare tire well etc, taking a few hints from people who go on to the track with their cars, in order to drop weight. We're talking something like 300-350 lbs (+/- 150Kg) extra on the Mk3 vs Mk2 which could be reduced.

Comments? I guess the drag coeff does play in much more than I had ever expected, also explains why some students in Europe were able to achieve something like 3L/100km in a Mk5, can't find a link right now but it was a red car with grill filled in.

[EDIT] Found the link:
http://www.autoblog.com/2007/05/01/9...-3-liter-golf/




Btw looking for that link I ran into this:
Drag coefficient of Mk3 Golfs - Club GTI

Mk 1 Cd.A = 0.83
Mk 2 Cd.A = 0.70
Mk 3 Cd.A = 0.66
Mk 4 Cd.A = 0.70
Mk 5 Cd.A = 0.76

Looks like the Mk3 would be the best thing to start with indeed! I guess I have been thinking too much in racing terms where WEIGHT is "everything", which isn't always the case when it comes to ecomodding!

[robchalmers]

personally I'd go for the retro small bumper, all my Mk2's were small'ies.

remember to drop it too....

If it ain't scrubbin you aint dub'in

[G2TDI]

Originally Posted by robchalmers

personally I'd go for the retro small bumper, all my Mk2's were small'ies.

remember to drop it too....

If it ain't scrubbin you aint dub'in

I associate Retro with Mk1 really.

To this topic belongs the fact that on a Mk2 there's technically THREE versions EURO small, US small and then BIG bumpers

Mk1 also there is small chrome euro, small chrome US, then plastic EURO (very similar in look to early Mk2)

Anyway see my last post above I think my direction on this might have changed since I initiated the topic, if ONLY we had Polos here I would go for a newer Polo for this kind of project but we do NOT so...

[G2TDI]

So yesterday I bought a 1994 Golf and today a 1998 Jetta TDI which will be donating the engine let's see how light I can get the Golf...

[COcyclist]

Originally Posted by G2TDI

Mk 1 Cd.A = 0.83
Mk 2 Cd.A = 0.70
Mk 3 Cd.A = 0.66
Mk 4 Cd.A = 0.70
Mk 5 Cd.A = 0.76

Looks like the Mk3 would be the best thing to start with indeed! I guess I have been thinking too much in racing terms where WEIGHT is "everything", which isn't always the case when it comes to ecomodding!

I will be watching with interest. My driving is almost all highway and I have gotten some of my best tanks with a carload of passengers and luggage. Low weight is more important in town and aero becomes more important on the highway as speeds increase. Weatherspotter just added one hundred pounds to the back of his Matrix and picked up 4-7 mpg, by his early testing. Threewheeler's is lighter but he increased highway mileage by 15%. I hope you try some of the aero stuff too (grill block, belly pan, smooth wheel covers, boat tail). I have felt that the TDI is a super highway car but I still have a few tweaks I need to do to mine. Perhaps you will beat me to it.

[G2TDI]

Originally Posted by COcyclist

I will be watching with interest. My driving is almost all highway and I have gotten some of my best tanks with a carload or passengers and luggage. Low weight is more important in town and aero becomes more important on the highway as speeds increase. Weatherspotter just added one hundred pounds to the back of his Matrix and picked up 4-7 mpg, by his early testing. Threewheeler's is lighter but he increased highway mileage by 15%. I hope you try some of the aero stuff too (grill block, belly pan, smooth wheel covers, boat tail). I have felt that the TDI is a super highway car but I still have a few tweaks I need to do to mine. Perhaps you will beat me to it.

Yes, I am also going to put in effort on the aero part (something I was not aware of having such importance prior to starting to read this forum so thanks guys!). So grill block (yes excluding for the IC intake area) and I am considering "shaving" (or as I would call it filling) the bumper too somewhat like this . Belly pan yes, I have a plastic one "left over" from my previous 1997 VW Golf 1.9TD (Canadian spec) plan on using it along with "DIY" panels under body. Smooth wheel covers yes still working on that in my head I would prefer see through options. Boat tail, sorry NO I just cant find myself doing that one while I will try for the best MPG I will not go all too crazy when it comes to the looks I want to do everything I CAN while maintaining a "normal" look .

While weight doesn't play as much role I do want to have "fun" driving it too whereby lighter weight will "lower" the impact of my at times heavy foot also I do drive in "stop & go" kinda of traffic too so. All-in-all I want to do as much as I can in areas I WILL do (weight & aero in front) so as to compensate a bit on areas I will NOT do (boat tail etc). Make sense?

[COcyclist]

Makes sense to me. I run Minilite style alloy rims in the summer, not very smooth. I like my car to look good and be fun to drive too. I think the real spun aluminum racing disks would look good but I can't bear to drill and tap mounting holes in my alloy rims.

[G2TDI]

Originally Posted by COcyclist

Makes sense to me. I run Minilite style alloy rims in the summer, not very smooth. I like my car to look good and be fun to drive too. I think the real spun aluminum racing disks would look good but I can't bear to drill and tap mounting holes in my alloy rims.

I've considered these Miata wheels (the 10.8Lbs), they are 4x100 but will need some "attention" in the centerbore aspect

Table of Wheel Weights

Along with some LRR 185 60 14, nice compromise to keep some drive ability yet some handling, anyhow this car can't even take 13" in the front due to brake size (I tried )

Cause with this agenda it's pointless to look at lightweight aftermarket wheels as they tend to go in the 15-16" and up, and larger diameter will typically mean wider wheels and "more" wheel period = more weight.

[G2TDI]

Still struggling with outside mirrors, while I'd love to remove both I don't know if I will due to both legal and safety issues...pass side is def being "deleted" ...