My TDI. (intro thread)

[Deezler]

Hey all,

Big fan of the site. Originally bought my car for its combination of mileage, good looks, alternative fuel capability and power modding potential (With the last item a central goal). Why sacrifice any of those things? I love this car!

Lately, I am more concerned with mods for mpgs.

Anyway, here she is at a little car show we had at work last Friday. Just about every other car was a gas guzzling beast....



Not too many takers for the biodiesel pamphlets on the windshield there... And its hard to see but I taped up the original EPA window sticker with 42/49 ratings. I think that a bit too cheeky for some of the older guys.



Several elements of the car are completely counter to fuel saving goals. Went from stock 15s to 17" wheels with 225mm wide rubber (but at 45 psi). Installed 20mm spacers on the rear. Well, actually thats about it.

Decided a grill block was a great first step.

Stock:





Finished:



And back on the car: (the MACK logo was a temporary joke)



The left grill opening feeds my intercooler, so no way I'm gonna hurt the flow to that one. I did cut some vents in the fender well behind it though. Scangauge showing just about no effect on coolant temperature, and none on oil temp gage either. (I feel like they warm up a bit faster, but its also summer now...) Recent reading has me convinced that blocking the upper grill would help more. My engine air intake is located there, but I could figure out a solution.

I think I'll try folding in the passenger mirror as a start, and if I get really used to it, lop it off and fab a plate. Already have a great skidplate, since I am down about 2" in ride height from stock (I swear, I did it for the reduced frontal area....haha)

This is how I fill her up:



99.9% pure biodiesel from blend of feedstocks (mostly Soy).

Just chipped the ECU yesterday. Must be at least a 15% gain in power, and many users report a 1 or 2 mpg gain from improved tuning. Unreal! New injector nozzles waiting to go in also; optimized spray pattern yields more power, lower emissions, and also slight bump in economy under cruising conditions. Now, granted I'll have more trouble with right foot control now, but I am hoping for either no change or a slight bump in mpgs with these mods.

I know lots of TDI (ALH engine) owners can cruise in the mid 50 mpg range all the time, but I am pretty happy with the 45 in mixed (mostly highway) I am getting right now. Best of 48 mpgs on recent road trip. Keeping in mind pure biodiesel is reported to give a 10% drop in power and subsequently fuel economy... but I don't see that severe a drop by any means. A bigger truck might.

Anyway, thats my car! Would love to hear your comments and recommendations. I am surprised there arent more TDI drivers striving for ultimate fuel economy... It would be an awesome platform for a basjoos type machine.

[SVOboy]

Looks nice so far! I just wonder what happened to the guy in the first picture.

How's the biodiesel FE compare to diesel FE?

Welcome to ecomodder

[tasdrouille]

Hey, welcome! Always nice to see a TDI joinning.

Have you bought a scangauge yet?

I agree the right foot is hard to control. Even when you're driving for FE, you have to give her a good run now and then to keep her from sooting up too much. Everytime I surprise myself seeing how the car likes to rev and how strong it can pull.

[Daox]

Welcome to the site.

[Deezler]

Thanks guys.

I would say I lose about 2mpg because of biodiesel, so maybe 5% drop max. Its hard for me to say exactly because I use biodiesel in the summertime and switch to an only 20% bio blend for the winter. So the straight bio has the benefit of warmer operating temps. End result is basically steady FE all year long.

I know everyone recommends driving style as the primary method of FE increase. I understand completely, and try to draft, coast and anticipate as much as possible. But when I wake up late for work I have to get here asap, meaning 80mph plus on the highway. Driving home I cruise much more. Now that my ECU is chipped I also like to accelerate a bit more.....

But my commute is about 40 miles of daily highway driving. Yes, I drive too fast. Often I have no choice but to go with the flow. But there still must be some gains that could be made in drag reduction. What do you guys advise as a next step?

I would really like to build a deck lid extension that tapers down gradually and in on the sides. I think lighter wheels with LRR tires and rear skirts are on the list too.

[Otto]

A friend of mine has a turbo diesel baby Benz. With jiggling of the turbo waste gate to sustain constant high boost without spool-up lag, he gets rubber in 4 gears.

He also runs it on cooking oil from a Chinese restaurant, and on home heating oil. I dunno exactly how legal that may be, but it seems to work just fine in his car.

[tasdrouille]

Originally Posted by Otto

A friend of mine has a turbo diesel baby Benz. With jiggling of the turbo waste gate to sustain constant high boost without spool-up lag, he gets rubber in 4 gears.

On the TDI I have a solenoid valve activated bleed for the vacuum controlled wastegate so I can crank up max boost from the factory 15 psi to 23 psi on the small kkk03 turbo. But only up till 3500 rpm. If I go past 3500 too much I'll blow it up pretty fast at that pressure.

I hardly ever use that kind of pressure anymore, but it always makes for fun times.

[msmnick]

Originally Posted by Otto

A friend of mine has a turbo diesel baby Benz. With jiggling of the turbo waste gate to sustain constant high boost without spool-up lag, he gets rubber in 4 gears.

That's not exactly an accurate statement. You can't reduce turbo lag by adjusting the wastegate, unless its malfunctioning or a poor design that creeps open at low psi, but it shouldn't. Some say a manual boost control can improve spool up, but if you understand whats going on there its not likely, unless again its not working right.

What does he do, just add a spring to keep the WG closed longer?

[msmnick]

VWvortex Forums: So... What did you do on your Diesel Today????
forums.tdiclub.com

You'll find a few people happy about the MPG the tdi's get them.

[Otto]

Originally Posted by msmnick

That's not exactly an accurate statement. You can't reduce turbo lag by adjusting the wastegate, unless its malfunctioning or a poor design that creeps open at low psi, but it shouldn't. Some say a manual boost control can improve spool up, but if you understand whats going on there its not likely, unless again its not working right.

What does he do, just add a spring to keep the WG closed longer?

Well, then, you'd better tell a gagillion Porsche 944 Turbo guys that what they've been doing for years was a figment of their imagination, and that their measured 3rd party acceleration and dyno test improvements were bogus. By manual or electronic control of the waste gate, higher boost is retained at baseline than before, meaning less time to go from that higher pressure baseline to full boost, and/or full boost at higher pressure than before.

Stock, the Porsche 944 Turbo has ~212hp, but with simple modification it goes to 300 hp, and with further (more expensive and extensive) mod up to 500 hp.

Research Rennlist.com and follow the threads in the 944 Turbo section. hat car is, btw, aerodynamically pretty slippery in stock configuration.

As for my Baby Benz turbo friend, as I recall he jiggered the wastegate spring. He has also run that td or home heating and vegetable oil. No problems reported. He got that car for $200 because the fuel pump seals were shot, and uneconomic for the prior owner to replace. I seem to recall that Benz seals were failure prone, whereas VW seals were not. Dunno if bolt on of a VW pump is workable on that car, or not. Worth a look, though.