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Old 06-18-2008, 07:57 PM   #1
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Hi all

I listed my cars in sig. My DD is the '98 Riv, I have a computer reprogrammer for it so I have modified timing tables, shift points etc. I also have a performance bug which doesn't help my economy, but I know there is a middle ground somewhere. I hope to keep the performance while improving my gas mileage. I should be able to since I can control when the auto trans locks the torque converter, timing tables... all that stuff.

We also just bought an '08 Passat Wagon for my wife. It's a 2.0T, the gas turbo 4 cyl. 6spd manual.

I have a lot of reading to do around here. My first general question is about shifting gears in the Passat. It seems like most of the time I can pretty much skip 2nd and 4th under normal acceleration. Am I saving any gas by shifting 1-3-5 instead of 1-2-3-4-5? I'm sure I will find an answer soon enough.

Don't be too hard on me about the '96 G30. I barely use it. I fire it up for heavy jobs only - i.e. towing my car trailer, moving, carrying 8+ people and all their luggage...

Anyway, Hi!
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Old 06-18-2008, 09:44 PM   #2
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Welcome! You can click on the Garage tab at the top and put your vehicles in the garage, as well as use the free gaslog tool for each vehicle. We'd be interested to hear how you do, and feel free to ask questions!
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Old 06-19-2008, 04:14 AM   #3
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Thanks!

Question about the garage - right now I have an excel spreadsheet with all gas purchases I've ever made, the date and odometer reading (with mpg and distance travelled calculations). Is there any way to import that stuff? I've got well over 200 data points for my car. A recent sample of it can be found here:

http://homepage.mac.com/derekcunning...GasMileage.xls
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Old 06-19-2008, 05:17 AM   #4
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AFAIK you would have to manually enter each data point.

I think the "six tank rolling average" in your spreadsheet would be a useful addition to the garage too, since that eliminates the "blips" that show up due to an unusual circumstance, partial tank fill, etc.

-BC
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Old 06-19-2008, 06:36 AM   #5
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Welcome. I like your taste in cars.

You're not the first to ask about importing historical data. I wonder if something can be made that will do the job.

I have a 2008 VW Rabbit with the 2.5L NA engine and the 5 speed manual, and I am a member of the golfmkv.com forum so I read a lot about the 2.0t and the 6 speed manual.

People on golfmkv.com are reporting 40mpg from their GTIs without hypermiling tactics, just by lightfooting it. I'm currently at a sustainable >35mpg with my Rabbit.

Specs for your wife's car:
http://www.vw.com/passatwagon/completespecs/en/us/
Specs for my car:
http://www.vw.com/rabbit/completespecs/en/us/

It looks like that car may be subject to the same too-low gearing as I am (and GTI drivers are too). Is 70mph in 6th gear 3000rpm? Then again, that gearing may be necessary with the 2.0t, which IIRC has little torque under 2000rpm and then suddenly makes loads of it above 2000rpm.

The drag coefficient of .297 is great!

Curb weight of 3,512 pounds isn't too bad. Considering the EPA ratings that are higher than mine (23/32 vs 22/29), I'd guess that you'll be able to do better than me unless your driving conditions are terrible.

51psi in my 195/65R15 tires on my 3,000 pound car is pretty comfortable, handles better than VW's recommended 32psi, should wear better, and definitely reduces rolling resistance. You should be able to inflate the tires on the VW and the Buick to their rated maximum without even noticing a difference in ride, and still get the benefits. I've got a link in my sig about tire pressure if you have questions.

I can't tell you how skip-shifting is going to work with the 2.0t and 6MT. With the 2.5NA and 5MT, skipping 3rd (1-2-4-5) made a big difference, but I decided I enjoy using all my gears and have found other ways to gain anyway. I may revisit the issue later. There's definitely potential for skip-shifting, the VW has decent power and gear ratios that are way too close.
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Old 06-19-2008, 09:55 AM   #6
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Hi Cow,

Thanks! I love the Riviera, it's an awesome cruiser. I haven't been able to pull better than 25 on the highway, but I wasn't overinflating then either. So much of my driving is city I barely get to make use of all these cool tips you guys have. I did up my psi to 40 and thought the ride was way too harsh, and I had traction issues (but due to my own heavy foot, which I'm trying to change).

I'm really curious about the skip-shifting, esp since I'm teaching my wife to drive a stick for the first time. Explaining 1-2-3-4 is easier than 1-3-5 but she complains that there is too much shifting I agree that the gear ratios are too close. The 2.0 T has a lot of torque, especially down low. VW changed to a smaller turbo recently on this model, which spools quicker and helps with the low-end quite a bit. I find I can hold 6th gear on the flats at 40 mph and it does fairly well. I can climb steep hills in a much higher gear than I though it would handle, I find 1500-1800 RPMs has a surprising amount of power. I had started out teaching that 2000 RPM was her target, but I'm going to lower that on our next lesson...

Yeah, it is just under 3000 RPM at 70 in 6th gear. Given how well the engine performs at lower RPMs I'm surprised they didn't gear it a bit higher, especially the way those germans drive!!
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Old 06-19-2008, 10:45 AM   #7
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What programmer do you have for your Buick? I was thinking of getting EFILive for my GMC and programming some simple, low shift points to use my V8's torque and reduce pumping losses. Search for that term, "pumping losses"; basically, sucking air past a closed throttle is difficult and wastes energy, so if you can open the throttle more but keep your RPM low, you save gas. This is a major portion of how I'm saving gas in my VW, but I can't do it in my truck because of the automatic transmission. Anyway, the reason I told you all that is that I'd love to hear the results of the shifting patterns I want to program into my truck, and I bet you can give me a clue how well it would work by trying it in your Buick.

I'd like to make it, very simply, always shift at 1500 rpm, even at WOT (and then I'd adjust that up or down as I deem necessary). I have a Tow/Haul mode (does the Buick have a "Sport" mode?) that uses a different program, so at the touch of a button I can have speed / responsive shifting like stock. I would also make it obey manual 3/2/1 selection as strongly as possible, and I could choose one of those gears to eliminate hunting when necessary. I don't suppose your Buick has the 4L60E transmission, by any chance...

Are you familiar with DFCO? Deceleration Fuel Cut Off, when coasting in gear (engine braking, even if you're not slowing much), it entirely cuts off fuel. I suspect that your Buick does not do it very much, if at all. I usually have to be engine braking for 10 seconds for my GMC to go into DFCO (I monitor the fuel injectors with a DIY fuel rate monitor, link is in my sig). Perhaps you can program your Riv to be more aggressive with DFCO?

As far as the VW...teaching the wife to shift is rather trying, isn't it? Mine can't grasp the concept of choosing the right gear for the speed you are going or plan to go, and she can't shift during a turn. She also takes FOREVER to execute a shift, and by the time she does, the gear I told her is no longer the right one.

Apparently those Germans don't mind screaming along at a million RPM. They seem to think that everybody needs close ratios for daily driving, even in a family wagon.
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Old 06-19-2008, 01:53 PM   #8
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The programmer for my Riv is one fairly popular in the GM 3800 OBD-II tuner world, a DHP (digital horsepower) 'PowerTunr'. It's okay, but I don't have access to as many parameters as I'd like to change. I do have access to the VE table and MAF tables, so I can falsely manufacture my own sort of DFCO. I am pretty sure I'm going to sell the PowerTunr and upgrade to HP Tuners 'VCM Suite'. The DHP has a horrible interface and they have pretty much stopped selling them. It still works, but improvements are not coming along very quickly. The trans in my Riv is a 4T65E-HD. I just had it rebuild with 3.29 gears (stock 2.93s), shift kit, hardened input shaft, things like that. The shorter gearing is appropriate for my driving since it's mostly stop and go and city. I haven't noticed any change in my highway gas milage, the RPMs are higher but the load is lighter, so it's been an even trade-off so far. The other nice thing is that I can increase my ignition timing through the roof for light throttle and cruise, which I think has helped significantly.

The Riv doesn't have a 'performance shift' button like the Pontiac GTP or Regal GS has, but I can edit shift tables based on throttle position and speed, so I can make it shift very early for light throttle use and increase fluid pressures and shift points for heavy throttle, and therefore don't need a button. It's basically fully customizable.

I've got one stretch of my otherwise city driving that's about 2 miles of winding riverside drive, speed limit 35. It's the only part where I can get into OD and have the TCC lock up, which I have set to happen at 38. The stock settings don't engage TCC until 47 mph, don't shift into 4th until 42. I can probably drop it into 4th even sooner... it's really fun tweaking the shift points on a computer controlled automatic! I'm doing my best to make it shift like I would shift it if I were driving a stick.

My wife has been awesome through the whole thing. It's 'her' new car, and she let me convince her she wanted a stick, even though she'd never driven one before. We've been working on it for a week and a half now, going out to big parking lots evenings, and she's off and running, even figuring out how to do hill starts (which is good, we have a lot of hills around here). I am a pretty patient teacher. Pretty much the last things we are working on are when to coast, and which gear to use for which conditions. The problem is my gear selection often changes by mood, so I'm not that consistent myself!

I love the way the Passat wagon drives. It handles well and it's really effortless on the highway, the aerodynamics are very obvious. I've also been reading a bit about the Ross-Tech tool for VWs. Have you played around with that tool? I can't tell from it's descriptions if it can edit and write parameters, or if it's just a scanner.

BTW I've tried to join the VWvortex forums (we've only had the car a week!) and haven't been able to get any kind of email from them... Do you know any admins over there?

-Derek
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Old 06-19-2008, 03:46 PM   #9
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Quote:
Originally Posted by deekster_caddy View Post
The Riv doesn't have a 'performance shift' button like the Pontiac GTP or Regal GS has, but I can edit shift tables based on throttle position and speed, so I can make it shift very early for light throttle use and increase fluid pressures and shift points for heavy throttle, and therefore don't need a button. It's basically fully customizable.
Well, one way I've really increased my FE is by using WOT and low shift points. However, if you can't switch programs on the fly you won't want to set an automatic that way, because then you'd have to shift it manually, which could get annoying (I assume the Riv has a column shifter).

Quote:
The problem is my gear selection often changes by mood, so I'm not that consistent myself!
That's normal, and she'll have to develop her own style. I understand how it would confuse her, though. I can't identify with people who don't know how to choose gears, because I've always been very aware of what gear I'm in even though I always had an automatic. This VW, which I have 6,000 miles on, is my first manual, though I've driven a few hundred miles in manuals before.

How's the clutch? The clutch in the Rabbit and GTI is numb and finicky; I thought maybe it was just my inexperience, but someone else posted a thread about it and got replies from quite a few people who have driven manuals for decades and still stall the Rabbit a lot.

Quote:
I love the way the Passat wagon drives. It handles well and it's really effortless on the highway, the aerodynamics are very obvious. I've also been reading a bit about the Ross-Tech tool for VWs. Have you played around with that tool? I can't tell from it's descriptions if it can edit and write parameters, or if it's just a scanner.
I love the seating position, my arms/elbows and legs feel like I'm in my pickup. I assume the Passat has a similar layout. The Ross-Tech Vag Com is incredibly cool, it can change a lot of cool stuff but I don't think it can change tuning parameters. I'm not sure. It's not completely documented; it has very low level access to the computer but nobody has fully documented all the parameters that can be adjusted, and of course nobody is willing to take the very real risk of destroying an engine to try different stuff. It's almost like opening your whole hard drive in a hex editor...

Quote:
Do you know any admins over there?
Nope, I'm on golfmkv.com. I had the same problem joining golfmkv.com though..
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Old 06-19-2008, 08:48 PM   #10
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How's the clutch? The clutch in the Rabbit and GTI is numb and finicky;
I think the clutch is light and easy, but has enough feel to know where you are on the pedal. Numb? Maybe you could call it that. It's certainly far from a performance clutch. I have stalled it a few times myself, but I'm still getting used to the new setup. Partially because it's so quiet, if you have the radio turned up or the A/C blowing hard it's hard to hear/feel the engine at all.

Oh, and the wagon is turning 2600 RPM at 70 (checked it tonight). Also according to the onboard trip computer I was averaging 34 MPG with the cruise set at 70 most of my trip. I know I can do better than that! (and I know the trip computer doesn't really count... but it's been reasonably accurate so far) (epa rated 29 hwy). At this point the car is still all stock, we haven't upped PSI or anything and it's doing that well!

Thanks for the warm welcome!

-Derek
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