www.tdiclub.com

Economy - Longevity - Performance
The #1 Source of TDI Information on the Web!
Forums Articles Links Meets
Orders TDI Club Cards TDIFest 2016 Gone, but not forgotten VAG-Com List Unit Conversions TDIClub Chat Thank You




Go Back   TDIClub Forums > VW TDI Discussion Areas > TDI Fuel Economy

TDI Fuel Economy Discussions about increasing the fuel economy of your TDI engine. Non TDI related postings will be moved or removed.

Reply
 
Thread Tools
Old March 18th, 2014, 05:13   #31
robnitro
Veteran Member
 
Join Date: Jan 2004
Location: NYC area, NY
Default

We don't just have an exhaust pipe/cat/muffler past the exhaust valves, we also have a turbo which creates backpressure, but I didn't make that clear (fixed my post above).

I meant the backpressure of the exhaust manifold which does change based on the turbo vane position. EMP.
More boost request, vanes more closed than if low or no boost request...

Simplified formula, but work of the turbo is work= pressure X flow.
If you can reduce the pressure drop that the turbo uses to make boost, it is doing less work.

Last edited by robnitro; March 18th, 2014 at 05:20.
robnitro is offline   Reply With Quote
Old March 19th, 2014, 17:06   #32
roadhard1960
Veteran Member
 
Join Date: Feb 2004
Location: Covington, Ga.
Fuel Economy: 48 mpg
Default

You are correct Rob. I was thinking about my answer yesterday morning and that turbo can affect resistance.
__________________
2003 Jetta wagon GLS, 5 Speed, Alligator tune, 34 psi tire pressure, 49.1 US mpg first 35k, 50 next 31.5k, 50.4 next 36k miles, cleaned intake twice and polished end runners last time, Mobil Truck & SUV or Delvac. Koni FSDs, VWs since 1977. Sprint 520 Nozzles for Christmas 2007. Ecodes with fogs and Eswitch. 485,000 miles and counting, original turbo. 2004 Dodge 2500 Cummins HO.
roadhard1960 is offline   Reply With Quote
Old March 16th, 2017, 03:37   #33
zovix
Newbie
 
Join Date: Dec 2006
Location: Sweden, Norrtälje
Default Cold weather milage

Hi there

I live in Sweden and I believe that it's good for the engine to block off intercooler or even to preheat air to the engine in wintertime at moderate loads.

Why? Because the air and fuel temperature affects the diesel fuels time to ignite. When the injector opens you have a slightly delay before the diesel fumes ignite in the cylinder. If you shorten that delay timing is more accurate and engine gives more power, if the delay is to long the timing is late even if timing is on time due to what the ECU sees.

Scania a Swedish engine and truck manufacturer even has thermostat controller to it's coolant to air liquid intercooler. The thermostat sets intake air temperature to 48 deg celcius and preheats air when colder and cools it when hotter air is pushed from the turbos.

Why don't we see this in cars? Because it's more expensive and VW thinks that poor mileage in cold weather doesn't effect too many customers.

/Z
zovix is offline   Reply With Quote
Old March 17th, 2017, 07:26   #34
Mike_04GolfTDI
Veteran Member
 
Mike_04GolfTDI's Avatar
 
Join Date: Nov 2003
Location: Richmond, BC, Canada
Default

I know this is an old thread, but anyway.... Regarding switching to an air-water intercooler with the goal of not intercooling in the winter, wouldn't it be a lot easier to just bypass the existing intercooler in the winter?

You know, make it so the air comes out of the turbo and goes to the intake directly? You'd need a charge pressure sensor in the pipe, because it is normally in the intercooler.

Anyway, that would be a simple way to test out whether not having an intercooler does any good.
__________________
2004 Golf GLS TDI 5-spd, DC Stage 1 Clutch, Evolution Atlas Skid Plate, Malone Stage 4 Tune, GT1749VB Turbo, 3 bar MAP
Mike_04GolfTDI is offline   Reply With Quote
Old March 17th, 2017, 09:09   #35
foggedz
Member
 
Join Date: Aug 2013
Location: Rockford, IL
Default

IMO the best thing for winter MPG's is to put a coolant heater on the car. Put it on a timer so that the heater runs for about 1hr prior to your trip.

The first 5-10 min of running a car that is not warmed up kills the most MPG for your trip. The MPG is so bad in the first few min that even after the car gets warmed up its difficult to offset those first few min unless you have trip time that is +45 min.

I have a 20 min drive to work. In the summer I average 45 mpg on that trip. In the winter with a coolant heater I average 43 mpg. If I forget to plug the heater in, I would be lucky to get 36 mpg.
__________________
foggedz is offline   Reply With Quote
Old March 19th, 2017, 14:50   #36
zovix
Newbie
 
Join Date: Dec 2006
Location: Sweden, Norrtälje
Default

Quote:
Originally Posted by Mike_04GolfTDI View Post
I know this is an old thread, but anyway.... Regarding switching to an air-water intercooler with the goal of not intercooling in the winter, wouldn't it be a lot easier to just bypass the existing intercooler in the winter?

You know, make it so the air comes out of the turbo and goes to the intake directly? You'd need a charge pressure sensor in the pipe, because it is normally in the intercooler.

Anyway, that would be a simple way to test out whether not having an intercooler does any good.
The thing is that the intercooler is doing good in low temperature but when in idle or light load it's cooling the air too much. Naturally it's no big money to save to retrofit a liquid to air intercooler just to gain some winter mpg. But if you combine it with other mods or want to increase your intercooling capacity any way the liquid to air intercooler could be worth looking in to. Especially if you often drive in cold climate.

/Z
zovix is offline   Reply With Quote
Old March 19th, 2017, 15:00   #37
zovix
Newbie
 
Join Date: Dec 2006
Location: Sweden, Norrtälje
Default

Quote:
Originally Posted by foggedz View Post
IMO the best thing for winter MPG's is to put a coolant heater on the car. Put it on a timer so that the heater runs for about 1hr prior to your trip.
The first 5-10 min of running a car that is not warmed up kills the most MPG for your trip. The MPG is so bad in the first few min that even after the car gets warmed up its difficult to offset those first few min unless you have trip time that is +45 min.
I have a 20 min drive to work. In the summer I average 45 mpg on that trip. In the winter with a coolant heater I average 43 mpg. If I forget to plug the heater in, I would be lucky to get 36 mpg.
In Sweden almost all cars have coolant or block preheater installed. Up in the north when temperatures fall to -30 deg. C a Diesel engine have a big difficulty starting with out.

Down here in the Stockholm region temperatures seldom drops below -20 deg C.

/Z
zovix is offline   Reply With Quote
Old March 20th, 2017, 13:37   #38
turbocharged798
Veteran Member
 
turbocharged798's Avatar
 
Join Date: May 2009
Location: Ellenville, NY
Fuel Economy: 40-50mpg
Default

Quote:
Originally Posted by foggedz View Post
IMO the best thing for winter MPG's is to put a coolant heater on the car. Put it on a timer so that the heater runs for about 1hr prior to your trip.

The first 5-10 min of running a car that is not warmed up kills the most MPG for your trip. The MPG is so bad in the first few min that even after the car gets warmed up its difficult to offset those first few min unless you have trip time that is +45 min.

I have a 20 min drive to work. In the summer I average 45 mpg on that trip. In the winter with a coolant heater I average 43 mpg. If I forget to plug the heater in, I would be lucky to get 36 mpg.
This is not the case on older TDIs with no DPF. VW did that to help get the DPF up to temp quicker.
__________________
99.5 Black Jetta TDI; DLC1019 nozzles, G60/VR6, ASV .5mm pistons, EGR delete, ASR/EDL, bilstein TCs MFA cluster.. Beater car. 365K miles and climbing.
99.5 Red Jetta TDI. Saved from the crusher. 270K
04 Jetta TDI .MFA cluster, reverse light mod, bilstein TCs 200K.
turbocharged798 is offline   Reply With Quote
Reply


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Liquid to air intercooler? Redneck Truck TDI Power Enhancements 22 August 10th, 2009 09:10
Liquid-to-air CAC? Pat Dolan TDI Conversions 13 July 10th, 2008 12:57
OFFERED: PWR 4x10" air-liquid intercooler, SilverBullet Private TDI Items for Sale/Wanted 0 January 4th, 2005 12:11
what is the liquid in the intercooler? VDubbing TDI 101 6 November 24th, 2004 10:32
Air-Liquid intercooling for $10 Keith TDI Power Enhancements 18 July 9th, 1999 09:14


All times are GMT -7. The time now is 14:41.


Powered by vBulletin® Version 3.8.5
Copyright ©2000 - 2017, Jelsoft Enterprises Ltd.
Copyright - TDIClub Online LTD - 2017
Contact Us | Privacy Statement | Forum Rules | Disclaimer
TDIClub Online Ltd (TDIClub.com) is not affiliated with the VWoA or VWAG and is supported by contributions from viewers like you.
© 1996 - 2017, All Rights Reserved
Page generated in 0.15195 seconds with 13 queries
[Output: 91.29 Kb. compressed to 79.21 Kb. by saving 12.08 Kb. (13.24%)]