2003 golf/jetta performance & mpg improvement

trafly

Well-known member
Joined
Jun 3, 2004
Location
Bay Area, Ca
TDI
2003 Jetta Wagon
Help: I'm wondering about increasing the performance and MPG in a 2003 Golf or Jetta. I have read what I can and spoken with Hayden at Dieseltuning. So my question is do people have a preference to 'chip' modification over the 'tuning box" and can these mods really improve both performance and MPG. Also, I want to run B100 or even convert to WVO and will the modification/chip still work? Thanks in advance.
PS. if anyone knows of a 03 golf or J. wagon GLS for sale I'd like to buy one.
 

Aggie05

Veteran Member
Joined
Feb 27, 2005
Location
Longview, TX
TDI
'03 2 door golf
I'm not at all certain that a chip or tuning box will increase your mileage. Injector nozzles will increase power and torque across the rev band, and according to legend, increases mileage too (a slight increase, though some people do report decreases). Right now I have a set of Sprint520's but I have not installed them yet. The chip will change the characteristics of how the car responds to different inputs. For example, the turbo will produce more boost, and at different RPMs.

My goal is to install the nozzles and get a rocket chip stage 0. This will make my ’03 TDI run at the Euro spec, 110HP and 195 ft-lb of torque. (I suspect this will not have too much of a negative impact on mileage)

I don't know anything about tuning boxes.
 

Dahlenburg

Member
Joined
Aug 24, 2005
TDI
Beetle 2000 Silver
I believe that if you soup up a car (introduceing more fuel and air to burn) you will lower your fuel economy. I see the claims on the chips... this will improve your economy!! Yea right.. I have a f-350 turbo diesel and added a 6 position swithch linked to a programmer. I dont think the black smoke comeing out of my exaust means I am burning less fuel. Just a thought:>)
 

Slave2school

Top Post Dawg
Joined
Mar 20, 2004
Location
Angus, Ontario
TDI
99.5 used to at least...
Nozzles do increase fuel economy if you drive like you did before you got them....most report chips increase highway mpg somewhat and decrease around town (mostly because of the "foot" factor). A chip does more than just pour the fuel to it.
 

Mike_M

Veteran Member
Joined
Sep 23, 2003
Location
Phoenix, AZ
TDI
Black 2002 Jetta GLS
I believe that if you soup up a car (introduceing more fuel and air to burn) you will lower your fuel economy.
Sorry, but most of the experiences here contradict your suspicions. Diesel engines are different from gasoline engines...you aren't automatically shoving more air and fuel down the engine just by souping it up. You only use more fuel if you use more power. There's no set air/fuel ratio, either. As long as you have sufficient air to burn all the fuel you're injecting properly, then the air/fuel ratio is fine. Generally, modern electronically-controlled direct-injected diesels (like TDIs) run very lean compared to a gasser.

Bigger nozzles do improve your fuel economy if you don't use the extra power. Why? Because the same amount of fuel is injected quicker (bigger holes), effectively advancing your timing by a small amount. This also gives the fuel more time to begin burning before the power stroke.

A chip can increase your mileage, again if you don't use the extra power, by changing the fuel map and the injection timing under part-"throttle" conditions. From what I've heard, I have a suspicion that this is what the milder RocketChips (Stage 1, Stage 2) do, but Jeff (jsrmonster) would be the one to ask for sure.
I have a f-350 turbo diesel and added a 6 position swithch linked to a programmer. I dont think the black smoke comeing out of my exaust means I am burning less fuel. Just a thought:>)
That is a tuning box, and usually those tend to have less control over the engine than a chip. On a TDI, a tuning box can't directly control boost, so you can dump in more fuel, but not more air...this leads to smoke and worse fuel economy. I suspect the same is true of your F-350's tuning box. So it's not all upgrades which will worsen economy...only ones that dump in more fuel for power's sake, without regulating other parameters of engine operation.

Hope that illuminates things a bit.

Mike
 

ZapBuzz

Veteran Member
Joined
Jun 28, 2004
TDI
jetta 2002 teal
for me...has been about the same, just much more fun

then again...I have a heavy foot.
 

Mike_M

Veteran Member
Joined
Sep 23, 2003
Location
Phoenix, AZ
TDI
Black 2002 Jetta GLS
for me...has been about the same, just much more fun

then again...I have a heavy foot.
Exactly...you're using the new power.
Not very much, though, or your mileage would have gone down.

Mike
 

2002tdijetta

Well-known member
Joined
Jun 15, 2005
TDI
jetta,2002,black
I had a rc2 installed and gained 4mpg at 70mph. I got 55mpg at 70 then got chipped went up to 59mpg. I have sprint 520's in now and have not lost any mileage that I can tell but I have yet to see if there has been a gain yet. I'll keep you posted. I wish I would have only chipped because with the injectors I get some clutch slippage whereas I was happy with the increase in power with no smoke and 4mpg increase. recommend rc2 only on stock clutch.
 

meganuke

TDIClub Contributor, Vendor
Joined
Mar 6, 2003
Location
VA/CT
TDI
2010 Ford Fusion Hybrid
RC2 and Sprint 520's is right at the limit for the stock clutch. Apparently all clutches are not created equal. Mine has this combo and doesn't slip at all. How many miles are on your clutch?
 

2002tdijetta

Well-known member
Joined
Jun 15, 2005
TDI
jetta,2002,black
I have 90,000 on the jetta. I have to really push it hard at approx 2100-2400 to make it slip in 5th. The other gears don't slip and outside of that area it doesn't slip. I also have motul 0w30 in it added a little power too. Its a torque monster. I also know in the 2002's (which I have)its an upgraded clutch than previous year models. I advanced the IQ and timing a little and now I can't tell if it slips or not. right at the edge. I just take it easy on it now. Its for mileage Its nice knowing if I need the grunt that it is there. Love this car!!!
 

ZapBuzz

Veteran Member
Joined
Jun 28, 2004
TDI
jetta 2002 teal
for me...has been about the same, just much more fun

then again...I have a heavy foot.
Exactly...you're using the new power.
Not very much, though, or your mileage would have gone down.

Mike
ALOT .. have to remember i had a heavy foot before i did any upgrades......jonesing even bigger injectors and for a vnt17 ....
 

KROUT

persona non grata
Joined
Aug 26, 2005
Location
JAX FL
I have a van aaken tunning box with pp520. I definatly had a decrease in mpg. But I drive it realy hard. If I drive the car like I did when it was stock I would get the same as I did before. I even ran without a maf for about a month i still got 36 mpg, but it smoked like a train.
 
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