I'm tired of chasing fuel economy on the ALH...

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
If your speedo is off, then so is your odometer. Maybe you weren't getting the mileage you thought you were.
It's definitely not off. I calibrated my speedometer, so at some of the higher numbers, I might be +1mph. So if it says 55mph, GPS might actually say 56mph. It was way off after I bought the car (like 7-8mph faster than the car's actual speed). Also, when I record fuel economy from my ColorMFA, it's VERY close to what it is hand calculated.
 

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
My rule is to drive an indicated 10 MPH over the speed limit. So indicated 80 in a MKIV is 77 actual, not enough over the 70 MPH limit on the turnpike to get a trooper's attention. If I get into a cluster of cars that are moving faster than 10 over I'll go with it, feeling I won't be picked out of a crowd. That can happen pretty often: I remember crossing NY State on the turnpike at 85 MPH (limit is 65) in a group of cars for hours.
I might do that, but having a radar detector and common sense also go a long ways, too. :)
 

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
As an update, I think my FE numbers are really skewered now. I came home to the smell of diesel and popping the hood revealed an unpleasant surprise. Replaced all my injector lines with junkyard pulls I just got today. #4 was misting out the top, and dripping at the bottom at the IP. I was also having some seepage from 2 and 3. So far, the replacements seem good, but I'll take a quick test drive to be sure. And here I thought I had initially improved fuel economy, getting almost 43 on the way to Austin.
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
When I had .205 nozzles from Franko6 with a 18PSI Stage 3 tune from VWMikel, I got 52MPG with cruise set at 75MPH (72 actual) hauling 4 adults and their luggage from Reno to Tulsa and back.
With my current 24PSI Stage 4 tune and .216's done by Franko6 I am lucky to hit 40MPG tank average. I do drive a bit more heavy footed these days, but crushing a Power Joke from a stoplight to well past the speed limit makes it all worthwhile. ;)
 

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
Not to pile on, but saw this earlier today:
I'm starting to wonder if my fuel leak could have some reasons why mine has been low. I can't fully test my car, because I keep having plastic parts related to the cooling system taking a chite on me... In the end, I'll probably end up with a practically brand new Golf...
 

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
When I had .205 nozzles from Franko6 with a 18PSI Stage 3 tune from VWMikel, I got 52MPG with cruise set at 75MPH (72 actual) hauling 4 adults and their luggage from Reno to Tulsa and back.
With my current 24PSI Stage 4 tune and .216's done by Franko6 I am lucky to hit 40MPG tank average. I do drive a bit more heavy footed these days, but crushing a Power Joke from a stoplight to well past the speed limit makes it all worthwhile. ;)
Interesting and thanks for sharing. Makes me wonder as well if I'd fare any better with a more custom tune. I'm also on a Stage 4 and 40 seems to be pretty normal.
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
I was coming back from fueling up an hour or so ago, and I started watching these two ricer ( is ricer politically correct these days?) up ahead. They were changing lanes together; the blue Honda in front was dropped and LED color matched lights underneath, fart can muffler, etc., and the Toyota MR4 I believe it was, was white, dropped, fart can, and pink LED's underneath, etc., etc.. I pulled along side of the Honda and looked over, he saw me and he sped up a little, so did I, I could hear he tagged the throttle, I replied in kind and had three car lengths on him in four or so seconds. I had to slow down, he caught up, he downshifted, I didn't and left him like he was nailed to a post. So Power Jokes and now ricers, I wonder what the TDI will embarrass next?
 

Nevada_TDI

Top Post Dawg
Joined
Aug 17, 2008
Location
Reno, sort of...
TDI
2001 Jetta TDI
Interesting and thanks for sharing. Makes me wonder as well if I'd fare any better with a more custom tune. I'm also on a Stage 4 and 40 seems to be pretty normal.
I see your list of mods and would like to ask a question, if I may, you are effectively running 24PSI tunes and both .230 and .240 nozzles. How thick is your exhaust plume? I must be missing something. With my IQ in the high 3's I get a bit of smoke on tip in, and then just a haze. When I had .230's with the almost same tune, I could have gone mosquito hunting and had no better power.
 

nicklockard

Torque Dorque
Joined
Aug 15, 2004
Location
Arizona
TDI
2010 Touareg Tdi w/factory Tow PCKG
I was coming back from fueling up an hour or so ago, and I started watching these two ricer ( is ricer politically correct these days?) up ahead. They were changing lanes together; the blue Honda in front was dropped and LED color matched lights underneath, fart can muffler, etc., and the Toyota MR4 I believe it was, was white, dropped, fart can, and pink LED's underneath, etc., etc.. I pulled along side of the Honda and looked over, he saw me and he sped up a little, so did I, I could hear he tagged the throttle, I replied in kind and had three car lengths on him in four or so seconds. I had to slow down, he caught up, he downshifted, I didn't and left him like he was nailed to a post. So Power Jokes and now ricers, I wonder what the TDI will embarrass next?
They always used to be really impressed and give me a thumbs up when they'd realized it was a diesel.
 

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
I guess I get to see if fuel economy is any better now. Got a longer piece of silicon piping from darkside for my SMIC (I had the boost pipe pop off once, so hopefully this eliminates that concern), AND I'm 99% sure I fixed any fuel leaks from the injection pump and injectors.

I feel like after I'm doing replacing things, this will be a 20 year old new car!

I see your list of mods and would like to ask a question, if I may, you are effectively running 24PSI tunes and both .230 and .240 nozzles. How thick is your exhaust plume? I must be missing something. With my IQ in the high 3's I get a bit of smoke on tip in, and then just a haze. When I had .230's with the almost same tune, I could have gone mosquito hunting and had no better power.
Technically, yes. Malone Stage 4. I have the Wuzetem .230's on it right now, because Frank talked me into putting those back in the car. The Gibonta .240's are in my Ute. The Ute smokes while idling, and as it turns out, it probably needs an engine rebuild (all cylinders are under 400), but that's another thread.

As for haze - it depends.. As noted above, I replaced one of my boost pipe silicons, so I don't have to worry as much about popping off a hose (it's happened before). I know if I floor it when I'm already doing 55-60, there's a haze behind me, but nothing where you'd think I'm a baby 6BT. It's enough to piss off the Prius/Tesla/California transplants to TX/people who don't know how to properly use the passing lane/etc.
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
Pkhoury says, "I know @Franko6 brags about getting 40mpg doing 90mph+."

It isn't bragging if you can prove it. It's not only me, but several of the injectors I've installed (after consideration of a LOT of variables...) have gotten extreme mileage. I NEVER promise those kind of returns. But also, I hear the hyper-milers trying to get 60+ mpg by driving 50mph, or less.

Time spent in travel is worth more than the gains in fuel economy. But I am not going to air my tires up rock hard. I'm not going to spend money on strange hyper mileage gizmos. It's possible but not probable to have large injectors producing great fuel economy. Some of the best economy performancewe have gotten was with the Bosch DSLA 105P 706 nozzles, which are the stock nozzles for the ALH engine with the 5-speed manual transmission. There can be some gains from taller 5th gear sets, as long as it's not overdone. I think the .681's, although apparently an obsolete part, helped. If you think running the engine below 1800rpm is an FE boost, you'll have to factor in the prematurely worn rings from lugging.

The OP has gone back and forth with me for months. One of the critical requirements of performance, whether it's hyper fueling or hyper power, you have to start with a very good engine. Good parts, excellent installation. NO CORNERS CUT. If, like one of the OP's engines, the compression is at 'rebuild' levels, don't expect chasing great injectors is going to do any good. 350psi? Your rebuilding the block and cylinder head.

The engine we test our injectors in has 500psi across the board; my own well-built engine. If you can't get the mileage, a great place to start is a quality engine
 
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Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
Pkhoury says, "I know @Franko6 brags about getting 40mpg doing 90mph+."

It isn't bragging if you can prove it. It's not only me, but several of the injectors I've installed (after consideration of a LOT of variables...) have gotten extreme mileage. I NEVER promise those kind of returns. But also, I hear the hyper-milers trying to get 60+ mpg by driving 50mph, or less.

Time spent in travel is worth more than the gains in fuel economy. But I am not going to air my tires up rock hard. I'm not going to spend money on strange hyper mileage gizmos. It's possible but not probable to have large injectors producing great fuel economy. Some of the best economy performancewe have gotten was with the Bosch DSLA 105P 706 nozzles, which are the stock nozzles for the ALH engine with the 5-speed manual transmission. There can be some gains from taller 5th gear sets, as long as it's not overdone. I think the .681's, although apparently an obsolete part, helped. If you think running the engine below 1800rpm is an FE boost, you'll have to factor in the prematurely worn rings from lugging.

The OP has gone back and forth with me for months. One of the critical requirements of performance, whether it's hyper fueling or hyper power, you have to start with a very good engine. Good parts, excellent installation. NO CORNERS CUT. If, like one of the OP's engines, the compression is at 'rebuild' levels, don't expect chasing great injectors is going to do any good. 350psi? Your rebuilding the block and cylinder head.

The engine we test our injectors in has 500psi across the board; my own well-built engine. If you can't get the mileage, a great place to start is a quality engine
HI,

I have read great things about your injector / head work.

How much fuel economy do you think can be gained by a really good porting (maybe even polishing) and other head mods (bigger valves etc) for better airflow and Volumetric efficiency ? (I have read that sometimes big airflow mods can hurt power / economy if there is not alot of swirling in the combustion chamber to mix things up or does that only apply to gassers with diesel benefitting simply by mega airflow?

I know most people who mod do so for power but how about work aimed at improving MPGs specifically ..... how do your cams figure into MPGs if NOT going for big power and running stock or nearly stock injectors / turbos?

How much is really good injector work / mods worth in terms of mpgs VS an out of the box injector / nozzle not profesionally set up / pop tested etc,,,

Sorry about all the questions but I figured since you were here in this thread .... well you know.

Thanks in advance for any and all help.

Andrew
 

IndigoBlueWagon

TDIClub Enthusiast, Principal IDParts, Vendor , w/
Joined
Aug 16, 2004
Location
South of Boston
TDI
'97 Passat, '99.5 Golf, '02 Jetta Wagon, '15 GSW
I don't think it takes a miracle to get 40 MPG at 90. However, I'm not sure where you can drive a TDI through at tank of fuel at 90 MPH.
 

energyflux00

Active member
Joined
Jun 22, 2015
Location
Syracuse, NY
TDI
Manual 5-Spd 2000 mk4 1.9L Jetta 187,000mi ALH
I drive the **** out of mine and if I do mostly highway I get 40-45. Back around when the mileage was 60,000 or so I was getting 50-52 if all highway. All stock.

That said... don't baby the engine. 1-2x a week open that **** up when getting on a highway or something. I didn't for about 2-3 months once and the tines in the turbo started getting stuck open which put the engine into limp mode during a road trip and I had to take care of the situation on the road. And it was a big pain in the ass.
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
Lol... Peter, I can't do miracles. Some just think it is when I do certain things. It's not a miracle when a cylinder head of mine goes another 500,000 miles after I built it. Some of the credit belongs to the owner. Never said I did a full tanks' worth of driving either. I had a 'front door' lead me 240 miles to KC. And it wasn't all at 90. Some of it was at 110... he was getting away. Coming back, I touched 90 a few times, but mostly 80. No grass grew under me... Full tank when we left. Filled up when I got there.

And 40mpg at 90 does not trump 65mpg @ 75mph, which a 98 New Beetle which is detuned is capable of. We built that entire engine, and injectors, a set of very exact 706's. It can't pass anything but a gas station.
 

Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
Lol... Peter, I can't do miracles. Some just think it is when I do certain things. It's not a miracle when a cylinder head of mine goes another 500,000 miles after I built it. Some of the credit belongs to the owner. Never said I did a full tanks' worth of driving either. I had a 'front door' lead me 240 miles to KC. And it wasn't all at 90. Some of it was at 110... he was getting away. Coming back, I touched 90 a few times, but mostly 80. No grass grew under me... Full tank when we left. Filled up when I got there.

And 40mpg at 90 does not trump 65mpg @ 75mph, which a 98 New Beetle which is detuned is capable of. We built that entire engine, and injectors, a set of very exact 706's. It can't pass anything but a gas station.
HI,

Love to hear all about the detuned 65 MPG at 75 MPH new Beetle.... Thats GREAT! ( I'm assuming no drafting?).

What was done to detune it? What's it like to drive ? If it can hold 75 MPH that's not too bad .... I could live with that !

I maxed out MPG wise at 2 tanks back to back 56 MPG before I had to start using AC then it's gone way down.... I never went above 65 to get those mpg figures.

Thanks

Andrew
 

Rrusse11

Veteran Member
Joined
Jan 23, 2014
Location
PA Deutsch Country
TDI
2002 Golf, 5spd; 05 Jeep CRD
Tires, Tires, Tires,,,,,,,,,,, my fat sticky tires make a difference, and the roof rack. I get high 30s around town drivin' like a cabbie, low 40s on the highway through the Appalachians pushing 80. Love the turbo and big nozzles, pulling the 1300# teardrop at 70 I still get low 30s, what's not to like? My turbo stays clean baby! :)
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
My formerly owned 2000 Jetta (son owns it now) consistently got over 50 mpg from when I purchased it in March of 2001 with 44k miles on it, until I retired at the end of March, 2008. No mods. That was seven years of commuting, on the job and weekend driving. I kept very detailed records in an Excel Spreadsheet until about 2013. From 08 to 2013 the MPGs did drop down barely below 50 mpg. I always filled it to the top each fill-up.

Anyway, tire size and inflation can negatively affect MPGs. Also, too tall or too short of tires will understated and overstate miles driven but will not be a major factor. I very seldom exceeded 70-75 MPH .. which probably was a piece of the good MPGs.

EDIT: The '02 ALH in my '84 Vanagon consistently gets 32-34 MPG tank after tank. It got over 26 MPG pulling a Popup Camper with four people on board and all their stuff on a very long road trip (12k miles in 30 days, again, detailed records). It has a Malone Stage 1 Tune, ERG delete, larger & shorter exhaust, but it also has a 4-speed with 4th gear basically the same ratio on the ground as the 4th gear in a Jetta... about 3075 RPMs at 70 MPH.
 
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Zak99b5

Veteran Member
Joined
Apr 30, 2021
Location
Albany NY
TDI
2003 Jetta TDI
EDIT: The '02 ALH in my '84 Vanagon will consistently gets 32-34 MPG tank after tank. It got over 26 MPG pulling a Popup Camper with four people on board and all their stuff on a very long road trip (12k miles in 30 days, again, detailed records). It has a Malone Stage 1 Tune, ERG delete, larger & shorter exhaust, but it also has a 4-speed with 4th gear basically the same ratio on the ground as the 4th gear in a Jetta... about 3075 RPMs at 70 MPH.
I remember the little Subaru motor in my Vanagon seemed to him along closer to 4K rpm on the highway. Do you have the freeway flier ring in your diff?
 

AndyBees

Top Post Dawg
Joined
May 27, 2003
Location
Southeast Kentucky
TDI
Silver 2003 Jetta TDI, Silver 2000 Jetta TDI (sold), '84 Vanagon with '02 ALH engine
I remember the little Subaru motor in my Vanagon seemed to him along closer to 4K rpm on the highway. Do you have the freeway flier ring in your diff?
When I started my Conversion Project, the first thing I did was build a transmission for the task. I spent about $1200.00 for parts, including upgrades in 3rd & 4th gears (1.14 & 0.77). Back in 2009-10, gears and parts were far cheaper than today. I also used a transmission with a 4.57 R&P. I am currently building a new transmissioon and at this point I have well over $2500 in it (don't tell my wife). Those dollar amounts are parts only. The OE transmission would demand 4,000 RPMs to do a smidge over 70 mph, depending on tire size. I am using a 4.13 R&P in this latest build, so, I guess you could say it is a Free-way Flyer. So, the Engine should be spinning under 2800 in 4th gear at 70 MPH, if my calculations are correct.

Project link (warning, it is very long, but pic loaded with a linked summary at the end)

Edited out the photo as no need to hi-jack the OPs Thread.
 
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pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
The OP has gone back and forth with me for months. One of the critical requirements of performance, whether it's hyper fueling or hyper power, you have to start with a very good engine. Good parts, excellent installation. NO CORNERS CUT. If, like one of the OP's engines, the compression is at 'rebuild' levels, don't expect chasing great injectors is going to do any good. 350psi? Your rebuilding the block and cylinder head.

The engine we test our injectors in has 500psi across the board; my own well-built engine. If you can't get the mileage, a great place to start is a quality engine
Remember Frank - I have two ALHs. The one with low compression is my Ute project, not my daily driver Golf, which works pretty good. I've actually been seeing outstanding fuel economy while towing, so I'm happier with this car now, but I've had to do A LOT of tweaks.

Also, thank you very much for your continued help over the months.
 

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
Tires, Tires, Tires,,,,,,,,,,, my fat sticky tires make a difference, and the roof rack. I get high 30s around town drivin' like a cabbie, low 40s on the highway through the Appalachians pushing 80. Love the turbo and big nozzles, pulling the 1300# teardrop at 70 I still get low 30s, what's not to like? My turbo stays clean baby! :)
I've been wondering about that. I use Continental ExtremeContact DWS06 on all the TDIs (except the Ute, because it doesn't leave the ranch right now, being incomplete and in need of an engine rebuild - it was also a $300 ALH).

I love these Contis, because of the grip they provide, especially when it's raining. I have wondered on fuel economy. I usually have mine inflated between 40 and 44. I pulled my 14x5 utility trailer the other day and did get almost 29mpg, and closer to 25mpg on the return trip almost fully loaded with vintage computers, both times doing 77. Actually, with the trailer empty, I was doing 75-85 much of the trip, but I couldn't keep up with @alphaseinor , who was in thet triple digits lol. My trailer also weighs about the same as yours, so who knows.
 

oilhammer

Certified Volkswagen Nut & Vendor
Joined
Dec 11, 2001
Location
outside St Louis (where it's safe)
TDI
There are just too many to list....
My one ALH with the MAF delete tune is more capable of higher MPG than the other, simply because the value stock in the MAF slot is lowish, so the maximum fueling won't ever get that high. It also can barely reach redline, even if I try. It just runs out of steam.

You could easily DEtune the engines even further, to get better fuel economy, but going south of 90hp isn't really all that appealing to a lot of people. I'll take a stock 90hp and a solid repeatable 45 MPG.
 

pkhoury

That guy with the goats
Joined
Nov 30, 2010
Location
Medina, TX
TDI
2013 JSW 02Q, 2003 Jetta Ute 02J swap, 2003 Golf 02J swap
My one ALH with the MAF delete tune is more capable of higher MPG than the other, simply because the value stock in the MAF slot is lowish, so the maximum fueling won't ever get that high. It also can barely reach redline, even if I try. It just runs out of steam.

You could easily DEtune the engines even further, to get better fuel economy, but going south of 90hp isn't really all that appealing to a lot of people. I'll take a stock 90hp and a solid repeatable 45 MPG.
When I drove the car home from CA, I was getting 45-47mpg, hand calculated and filling up to the top (did a ventectomy at my dad's house before I headed back home). The car had a decent amount of acceleration, but nothing like now. Makes me wonder now how much better fuel economy would get with a slight detune, but without killing some of the fun.
 

Franko6

Vendor , w/Business number
Joined
May 7, 2005
Location
Sw Missouri
TDI
Jetta, 99, Silver`
When working toward extreme mileage or extreme power, there have to be sacrifices. I certainly agree with OH. I don't have a 'crazy big' engine, but I do know that proper porting, rings (yeah, we got some crazy performance rings...) even the bearings have little incremental improvements, but the largest single factor, in my opinion, is very accurately calibrated injectors. Certainly, that is not the ONLY thing that is important for performance/ economy, but it is the MOST important. After all, in order to get great performance, the diesel engine should run with great efficiency. NO BLACK SMOKE.

As an example of power/ economy, one customer was complaining about the lack of economy. His situation, his nozzles were the most cloned '520's', that are noted as 'power nozzles'. There are some that are total trash, some that are dubious and some that actually rank as useable. His were from a 'dubious' source, but we were able to schmooze them into shape by honing the bodies until the needle was proper height. The result was it cut the prematurely leaking fuel, I balanced the results and sent them back to the owner.

First thing he complains, "It's not got the POWER it used to!" Wah, wah, wah! But did it great fuel economy? You betcha. Now, this case is not mutually exclusive; that you can't get power AND economy out of the same set of nozzles, but also note, I did not say they were great nozzles. They were 'dubious'. Or, you can't make a silk purse, etc....

It is possible, within limits, to get very good mileage from reasonably large nozzles. I will not hold VERY large nozzles of that capability. There are too many of those which are questionably built that are way outside the parameters of the engine's ability. They are so large, they cannot be stopped from leaking. The leaking, when extreme power is the desire, is not a big concern as the last thing on the list of importance is fuel economy.

There have been 220hp nozzles made here that got a confirmed 52 mpg, but once again, there is no guarantee. Each engine has it's own character and every one becomes it's own custom creation.

It all starts with a blue-printed engine that works perfectly.
 

AGTDI

Member
Joined
Jan 22, 2021
Location
AG CA
TDI
2002 Jetta Wagon
What kind of FE does a Suburban get at 80? I wonder when I see those big vehicles blow by me.
2003 Yukon XL 2500 4x4 with 8.1 gas:
Total Combined Ave 9 MPG
Freeway @ 70 MPH - 13
Freeway @80 MPH - 11

My 02 ALH Wagon commuter vehicle has averaged 46.xx mpg over the last 100Kmiles....average highway speed for me is about 73-78 actual on relatively flat, moderate temperature on CA central coast.
 

jmodge

Veteran Member
Joined
Jun 18, 2015
Location
Greenville, MI
TDI
2001 alh Jetta, RC2 5speed daily commuter and 2000 alh Jetta 5spd swap, 2" lift, hitch, stage 3 TDtuning w/502's backroad cruiser
Donna’s is still doing 50-52 summer, 47-49 winter. Combined average but mostly highway
 

Andyinchville1

Veteran Member
Joined
Apr 7, 2016
Location
Virginia
TDI
2003 Jetta TDI wagon, 5 sp, 226K miles
When working toward extreme mileage or extreme power, there have to be sacrifices. I certainly agree with OH. I don't have a 'crazy big' engine, but I do know that proper porting, rings (yeah, we got some crazy performance rings...) even the bearings have little incremental improvements, but the largest single factor, in my opinion, is very accurately calibrated injectors. Certainly, that is not the ONLY thing that is important for performance/ economy, but it is the MOST important. After all, in order to get great performance, the diesel engine should run with great efficiency. NO BLACK SMOKE.

As an example of power/ economy, one customer was complaining about the lack of economy. His situation, his nozzles were the most cloned '520's', that are noted as 'power nozzles'. There are some that are total trash, some that are dubious and some that actually rank as useable. His were from a 'dubious' source, but we were able to schmooze them into shape by honing the bodies until the needle was proper height. The result was it cut the prematurely leaking fuel, I balanced the results and sent them back to the owner.

First thing he complains, "It's not got the POWER it used to!" Wah, wah, wah! But did it great fuel economy? You betcha. Now, this case is not mutually exclusive; that you can't get power AND economy out of the same set of nozzles, but also note, I did not say they were great nozzles. They were 'dubious'. Or, you can't make a silk purse, etc....

It is possible, within limits, to get very good mileage from reasonably large nozzles. I will not hold VERY large nozzles of that capability. There are too many of those which are questionably built that are way outside the parameters of the engine's ability. They are so large, they cannot be stopped from leaking. The leaking, when extreme power is the desire, is not a big concern as the last thing on the list of importance is fuel economy.

There have been 220hp nozzles made here that got a confirmed 52 mpg, but once again, there is no guarantee. Each engine has it's own character and every one becomes it's own custom creation.

It all starts with a blue-printed engine that works perfectly.
HI,

I agree with the "if you see black smoke you are wasting fuel" since it's just unburned fuel spewing out.

Just curious but about how much does it cost to optimize / adjust a set of injectors?

If I had them done on my car (I just got off the shelf stuff from Kerma ... no testing / adjusting) is there a realistic MPG gain I could see without reducing power per se?

Thanks

EDIT : My engine is in pretty good shape ... it can get fuel mileage per my Fuelly account ... It does not leak or burn any significant amount of oil (last oil change I may have added a quart or so at most but that is over about 27K miles (my approximate last OCI ... lab cleared me to go 35K on my next change based on oil analysis).
 
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