VW GTI - Heavy modding done - what next?

[JethroBodine]

Originally Posted by Frankencar

I already ahve a scangauge installed - it's quite helpful. I find it overestimates fuel consumption when driving hard and underestimates when driving really carefully..

Brilliant! I've been trying to figure out why my MPGuino reads differently from time to time. I think it's reacting opposite to your Scanguage. Must be a VW thing.

[Frankencar]

Well, the GTI is getting decent MPG even after the very non-eco-minded mods it got (bigger nozzles, more boost...) I think MPG over 60 can still be a normal thing if I keep my foot out of it. I'm just glad it climbed out of status and can get out of it's own way ok now. Here is the best run from last night:

1/4 Mile in 14.658 Seconds at 94.757 MPH:

GTI TDI Run 5 14 658 at 94 757 - YouTube

[JethroBodine]

Nice run for a 4-banger diesel. Nice ride.

[ECONORAM]

Originally Posted by Frankencar

Sooo - I have had this 1991 VW GTI for almost 3 years now - and for the first 2 it was getting aobut 21MPG. In August of last year we fixed that with an AHU TDI:

I'ts mostly modded to go fast so I was shocked at how good the MPG was once I started driving it. I'm really hooked now! I even drove a whole 1100 miles as carefully as possible just to see how it does and was able to get it up to 78MPG! though the lifetime average is only about 60MPG.

Since the swap I have added the following eco-mods:

1: High temop thermostat (92 rather than 87 degrees)
2: Taller 5th gear (.622 was .756)

My question now is - what else can I do without getting really crazy? I want to keep it looking as stock as possible. Here are my thoughts...

1: Maybe a belly pan of sorts
2: LRR Tires (already in the plans when it gets 5-lug and Porsche brakes)
3: Some sort of tasteful grill block?
4: Maybe eventually go 6-speed with a .59 5th gear

This site has been a great resource so far - and I think the best info for future MPG gains will come from all you you MPG gurus.

I am envious. I had an 84 GLI, and later a 91 Jetta. Both would have been good diesel candidates. The 91 had PS that I deleted. It'd get low 30s for mpg... I am tempted to find a similar car and engine and try this myself.
Besides the grill block and belly pan, you could make some small fairings to put in front of each wheel/tire to guide the airflow around them. Maybe a rear wheel skirt too...

[Big Dave]

While Frankencar indicated his desire to keeping the car looking as "factory" as possible, his MPG success leads one to wonder what would be the (MPG) result if one took an old VW, transplanted in the diesel and gave it the full "basjoos" treatment.

[LeanBurn]

I had a 92 turbo diesel (not eco diesel) and it would get 5.2L/100kms (45mpgUS) all day long with only cruise used on the highway, I didn't know about aero at all back then. I got ~4.3L/100km (55mpgUS) a few times on some long summer trips when there was no wind. Good car for fuel economy, I was always seeming to tinker with it trying to get it not not run too hot.

[Frankencar]

Originally Posted by ECONORAM

Besides the grill block and belly pan, you could make some small fairings to put in front of each wheel/tire to guide the airflow around them. Maybe a rear wheel skirt too...

Probably not going to do wheel skirts - or if i do, something tasteful and easily removable, but the small fairings in front of each wheel could be discreet and would probably make a big difference. Te wheels are very much out in the wind on this car.

Originally Posted by Big Dave

While Frankencar indicated his desire to keeping the car looking as "factory" as possible, his MPG success leads one to wonder what would be the (MPG) result if one took an old VW, transplanted in the diesel and gave it the full "basjoos" treatment.

Not a TDI, but a VW soon-to-be-diesel with the full Aero stuff - I bet it will get crazy good MPG! http://ecomodder.com/forum/showthrea...tml#post263738

Originally Posted by LeanBurn

I had a 92 turbo diesel (not eco diesel) and it would get 5.2L/100kms (45mpgUS) all day long with only cruise used on the highway, I didn't know about aero at all back then. I got ~4.3L/100km (55mpgUS) a few times on some long summer trips when there was no wind. Good car for fuel economy, I was always seeming to tinker with it trying to get it not not run too hot.

Some IDI's run hot - not sure exactly why. My TDI tends to run very cold. On cold days (and I'm talking below 55 F! ) I can't ever get it up to temp. I will definitely need to get a grill block done before the summer is over. My current project is to get a complete new suspension in it with bigger brakes to help slow this thing down and it will be getting some LRR tires and the belly pan while I'm under there. I'm trying to get it all in before my road trip to Colorado this summer.

[mwebb]

My TDI tends to run very cold. On cold days (and I'm talking below 55 F! ) I can't ever get it up to temp.

replace the thermostat , use a VW part do not use aftermarket

[Frankencar]

Originally Posted by mwebb

My TDI tends to run very cold. On cold days (and I'm talking below 55 F! ) I can't ever get it up to temp.

replace the thermostat , use a VW part do not use aftermarket

Did that - then upgraded to 92 degree thermostat - still - no dice. It's just that light a load.

[euromodder]

Make the EGR optional instead of blocked ?