Cetane boost = MPG boost?

Joined
Feb 9, 2021
Location
Wisconsin
TDI
2002 Jetta Wagon TDI
Hello fellow TDI owners!

I am curious about the effects of cetane on highway fuel economy. I’ve been running 2Diesel in my ALH, and I’m curious if I would see a boost in fuel efficiency if I added Cetane boost to a tank of fuel. And if I do, would it be worth the dose of Cetane? I figure $10 for a 16oz bottle of AmsOil Cetane boost and about 1.6oz to treat a 16 gallon tank for ten doses at a dollar a dose. Since I am not knowledgeable when it comes to the cetane levels in standard D2, or really how Cetane works in general, I’d be grateful for any knowledge y’all can share about this topic! :)

Thanks!
 

lemoncurd

Well-known member
Joined
May 24, 2019
Location
Vancouver, WA | Willimantic, CT
TDI
MK6 Jetta SloWagon TDI (Golf Varient)
I am on the line between fuel additive is snakes oil or it actually does something. When I run additive its always power service (power stop?) and its the grey bottle. I swear the butt dyno says its a tiny bit quicker and that my trip odometer goes just that much further.
So yeah, I would say it does improve MPG some what! That stuff also has the added benefit of lubing the fuel system, which if you have a hand grenade of a HPFP like I do (CP4) then that would mean alot
 

Lightflyer1

Top Post Dawg
Joined
Sep 13, 2005
Location
Round Rock, Texas
TDI
2015 Beetle tdi dsg
It almost never pays for itself when used as you are wishing to. You will never prove it helps economy to any great extent. Same for lubricity. Easy to prove if it works for cold temps though and is useful in that regard. Cetane also has a point of diminishing returns. Adding more and more doesn't just keep increasing the gains. Because of that the better the fuel is to start with the less change you will notice. So just find a station that has good fuel. I am already using fuel with a small bio percentage in it so lubricity should be as good as any additive. I have tried most of the major additives back when and noticed no noticeable difference. Don't use a single one any more except for cold temps.
 

CleverUserName

Veteran Member
Joined
Oct 25, 2014
Location
NorCal
TDI
2014 OZ Cruze CTD & 2010 JSW 6MT
Boosting cetane does improve fuel economy if your fuel is below 50. After 50 it doesn’t do anything and if it’s significantly higher like 70+ it can actually reduce fuel economy as the peak cyl. pressure is reduced.
 

Stupendous60

Veteran Member
Joined
May 18, 2019
Location
TX
TDI
2000 Beetle TDI automatic "Otto", 2000 Beetle TDI manual "Amfeny", 2000 Beetle TDI manual "NC", 2002 TDI Beetle manual "Manny" 2019 Beetle gas/auto "Nunu"
I put 4oz Diesel Kleen cetane booster every other tank fill. Cars are smoother an have more pep especially when down to 1/4 tank and below. (less weight too) I love a cool rainy day under this circumstance especially! Cleaning advantages ang mpg increases? If it does, great.
 

bhanson

Well-known member
Joined
Apr 14, 2008
Location
Dayton VA - in the Shenandoah Valley near Harrison
TDI
2000 Golf TDI / Automatic Tranny
I cant definitely tell the difference between 50 Cetane and 40. Easier starts, more power. But, I've been surprised driving up and down the coast that I seem to get the same mileage on either. Now, Temperature, that impacts fuel economy. When it gets really cold out, my mileage drops by more than 10% on the highway.
 

Mongler98

Top Post Dawg
Joined
Mar 23, 2011
Location
Northern MD (HAGERBUSH)
TDI
98 Jetta TDI AHU 1.9L (944 TDI swap in progress)
Hello fellow TDI owners!

I am curious about the effects of cetane on highway fuel economy. I’ve been running 2Diesel in my ALH, and I’m curious if I would see a boost in fuel efficiency if I added Cetane boost to a tank of fuel. And if I do, would it be worth the dose of Cetane? I figure $10 for a 16oz bottle of AmsOil Cetane boost and about 1.6oz to treat a 16 gallon tank for ten doses at a dollar a dose. Since I am not knowledgeable when it comes to the cetane levels in standard D2, or really how Cetane works in general, I’d be grateful for any knowledge y’all can share about this topic! :)

Thanks!
the ONLY way to get better performance and MPG is to learn how to drive. get a scangauge II and learn how to be more efficient.
stay away from snakeoils.
 

Guttboy

Veteran Member
Joined
May 8, 2005
Location
Colorado at 7500'
TDI
Jetta MkV 2005.5 Platinum Gray/Gray Leather Pk2
Hello fellow TDI owners!

I am curious about the effects of cetane on highway fuel economy. I’ve been running 2Diesel in my ALH, and I’m curious if I would see a boost in fuel efficiency if I added Cetane boost to a tank of fuel. And if I do, would it be worth the dose of Cetane? I figure $10 for a 16oz bottle of AmsOil Cetane boost and about 1.6oz to treat a 16 gallon tank for ten doses at a dollar a dose. Since I am not knowledgeable when it comes to the cetane levels in standard D2, or really how Cetane works in general, I’d be grateful for any knowledge y’all can share about this topic! :)

Thanks!
For about 3 years from purchase, I ran Powerservice DieselKleen in the Jetta.

Then in 2010 I never ran it.

Car is bone stock and depending on who drives, it gets anywhere from mid 50 mpg (wife) and high 40s (me).

I do NOT baby the car at all and literally slam the pedal.

I just started running Powerservice again as we decided to keep the car due to a ton of factors. Will see if it makes a difference. However, running it consistently as the original owner we haven't experienced an issue with the engine whatsoever.

Did it make a difference? I am not sure. Not sure it hurts but at 200K miles and still going strong it may have helped.
 

Daemon64

Veteran Member
Joined
Jul 19, 2019
Location
Tyngsborough, Massachusetts
TDI
2015 Q5 3.0 TDI - Retired, 2021 Q5 55e PHEV
it never made an economy difference for me. The engine did seam a little quieter in winter weather, but thats about it. I took it as cheap insurance using Stanadyne and thats about it..
 

MukGyver

Veteran Member
Joined
Dec 11, 2020
Location
Sierra Ca
TDI
2004 Jetta PD
Using Power Service and 2-stroke oil and engine definitely runs smoother. mpg's doesn't seem to change much. I initially added too much 2-stroke evidenced by power reduction. I do periodic injector cleaner from the filter line too, at the cost of pd injectors just hoping to keep them clean and lubricated as long as possible.
 

Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
I have read that cetane boost does help MPG's of low cetane fuels up to a point.

I mainly use power service (gray bottle) at about 4 ounces per 8 to 9 gallon fill up (yes, probably way overdose but it's what I have been doing) AND Wal Mart TC3 2 stroke oil (about 4 oz per 8 to 9 gallon fill up).

My first injection pump made it to 315K miles .... it'll be interesting to see if this extra brew of "potions" helps the new pump last longer.

As far as MPG I have not experimented without running the extra additives with the new pump (I am at 430K miles now so the pump has about 115K on it so far).

Andrew
 

MukGyver

Veteran Member
Joined
Dec 11, 2020
Location
Sierra Ca
TDI
2004 Jetta PD
I think the stuff I use is the same. Super Tech Outboard 2-cycle oil TC-W3 ashless .. ("Blue juice") HFRR 474
 
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