Engine/Transmission (1994 - 1998) Injectors, whats best?

[Reddog1]

LSMITH - Do you really think that the difference in our trucks from DC is timing and cams and pistons, or even compression ratio?



To a point, I would agree that "it is the loose nut behind the wheel that is THE factor in fuel economy".





When you consider the difference between 16 and 27. 5 MPG, there has to be something else. Even if you just consider 17 to 23 mpg, that is a lot. If you have that much difference in a gasser, people who BOMB them will provide a tangible you can do to at least get the numbers close.



Koa Man's truck has an excuse, GCVW of 16 to 20K most of the time.



illflem has provided some tangible causes.



Has anyone taken this on as a challenge?





I repeat the following:



"TDR has over 14,000 members. So many of us can tell others how much HP you can get, and how to achieve it, and prove the HP on the Dyno. Yet, I have not found a post where someone says, “my truck was getting 18 MPG. I made the following mods and now get 24 MPG”. I want to see how it is done. Respectfully, the mileage claimed by some, would be easier to believe. "





Wayne

 

[rnolen]

I agree with reddog! I hear stuff about timing alot, but I really don't hear much about people changing cams and pistons to get MPGS. The timing is clearly a problem on the 12 valvers. That is why i am getting mine checked and set. There is alot of difference between 17 and 27 MPG, and I am one of the lower ones. It sounds like a lot of people do different things to get higher MPGS, not just one or two things.

Nice Discussion

Russ

 

[LSMITH]

Wayne, nope. The difference in stock trucks is timing related but that is only part of it. Tolerance stacking throughout the drivetrain can go in the right direction and also the wrong direction. I think that is the major factor in the differences. Some trucks run really well, while others are pigs, they are all individuals to an extent.



How many of these trucks have you seen on the highway dog tracking by a full 3 inches or more? That right there is probably good for 1 mpg if not more. A couple dozen little things can add up to a large number.

 

[Reddog1]

rnolen - As I previously stated, illflem has provided some tangible causes. LSMITHs most recent post is very relevant as well.



The problem I am having is identifying someone that has intentionally challenged their mpg, made changes, and had a significant positive change in mpg. I don't count less that 1 mpg as significant, and that 1-mpg has to be repeated.







LSMITH - Interesting thoughts. I am a machinist (currently not practicing), and I have a teaching credential on the subject. I agree that tolerance stacking would have an impact. I just don't think it would be that great.



I never gave thought to the dog tracking. I intend on having my truck aligned soon. I will note how far out it is.



I really hope that timing plays a big roll. Santa brought me a timing kit for Xmas. When the weather breaks, I will put it to use.







Wait a minute. I think my truck has been insulted. You wrote; "Some trucks run really well, while others are pigs... " :{ LOL





[edit]

Birdy Birdy in the sky

who just po poed in my eye

I'm not angry, I won't cry

I'm just glad that cows don't fly







Wayne

 

[rnolen]

I stand corrected. I did not understand everything LSmith was talking about. My fault.

Sorry

Russ

 

[JJW_ND]

High and Lows and extremes...

Here is my take on MPG. When hotshotting I would run empty for 750 miles then tow for 750. Did this for 5 years with this truck. Same road, different day, wind, air temps, and changes to truck. I have logged every gallon and mileage and pay attention how full the tank is fulled. I have an axillary tank and generally run until it is emtpy ... lots of miles that either did good, bad or somewhere in between. I have verified my odometer (they are off). My best mpg was 26. 5 (1,069 miles on that tank) my worst was 5. 5 (load of flatbeds stacked, 4th gear on the govenor for 454 miles).



What is interesting in my case is my best mileage appears in the early spring or late fall. I run premium straight #2 year round plus Stanadyne when temps go below zero. I generally have my winter front from fall through spring. I believe the winter front provides warmer then normal engine temps which help get good mpg. The other thing (more evident now that I don't pull anymore) is I was make a good pull ever few weeks (700 miles of WOT). I truely believe it is good for engine effiecieny to work the dog ***** out of these engines on a regulare basis.



My pulling MPG definetly went up after plate slid and minor AFC adjustmentsts. In town mileage probbaly went down but on highway stayed the same.



I also agree that boost (4 - 6) and EGTs (500 - 600) are key to attaining acceptable mileage even if that speed is 65.



I just recently had my timing bumped quite abit. Time will tell what effect it has but so far mpg appear to be up. My boost and EGTs are definetly down for the same given RPMS.



If I use my truck as typical respresenitive of 12V trucks, (running empty at a give engine speed and load ) the extremes would be 22 - 25 on the highside, attained by very few trucks. 18. 5 to 20. 5 would be the sweet spot, this should be attainable by the majority of trucks. Low side 14 - 17, not typical nor respresentive but reality. A very small percentage of all trucks fall in the highside and lowside. Most should fall in the middle. These mileages are over the road crusiing mileage. Yearly averages (exclusive of towing) would be 2 - 3 MPG less... . mine are!



If I was going to attempt to get the best MPG out of my truck: make sure engine is thoroughly broke in. I would change all fluids to full synthetic including running 5W30 in engine (I did and I does help). Run premium fuel with Stanadyne and have clean filters, free flowing exhaust and intake. Do when air temps are in the 50 - 70s but use winter front (optimal intake air temps but cool enough to run winter front which will raise engine coolant temps which running empty will not by itself. Drive any speed that keeps boost at 4 - 5 and EGTs under 600. I would expect to get low twentys!



jjw

ND

 

[Reddog1]

JJW-ND - Thanks for the info, very informative.



Your signature says you changed head gaskets.



1. Are you concerned on blowing a head gasket with 20 degrees of timing?



2. What was your timing set at with your previous gasket?



3. Do you recall the mpg increase after moving from stock timing (assuming you did), before the 20 degrees?





Wayne

 

[JJW_ND]

Leak by TStat Housing

I had a very slow coolant leak by the Tstat since 120K. Finally got sick of the smell. Only used about gallon every 20K miles.



We ended up pulling the injection pump to replace the side cover gasket while head was off. I never had timing changed. It should have been stock. I ran very good before so it could not have been off.



The shop I used likes to run higher then normal timing. I said I would give it a try. I did the . 020 over only because a . 010 did not show up. Milled . 008 off. Everything looked very chean and tight.



I might get by with the extra timing with the lower compression. Should help reduce the cylinder presure some. Other then lots of white smoke (more th normal) when starting cold, it really runs good.



Like I said above, I am running 50 - 100 degrees cooler egts and 2+ pounds boost less at 2000 rpms then before.



Need more miles and time to make a accurate statement about the higher timing. So far I like it.



jjw

ND

 

[jburnes]

Got Gauges

The milages variations are interesting. All variables included.

I do have gauges, came with my Banks set-up (ETG&Boost). I added transmission temp "G" too. Getting to any good answers to my questions about good injector/miliage etc. was like wading knee deep in mud after four beers (six on a bad day). Injection angles and atomization were part of my concern. Its seemed that a Horse-S%#t Slinging contest was waiting to happen, Wup there it was. Sorry to those who were hoping for an answer. I never thought it would come to this! For those of you who gave good advice,Thanks! For those of you who made me aware how great your miliage is... I'm not sure if I should thank you, I'm getting 16 mpg at best. As for you slingers and slinger bashers (which I'm not sure who's who?) just check your boots at the door... HA! Oh, on such a mechanical type 12 V it sure is interesting to see the differences and Yes I'll check with Piers. Know where your wifes birth certificate is? Make sure all of you tape a copy to the back of your calculator... Just goes with some of the territory. . HA!



'96 4X4 3:54 285's Auto 2500 4"T-T Bank'sBombed Trannydone

 

[rjones]

I'm getting real nervous now about putting the 370 in cause I only get 10. 5mpg for some reason and its not the driver.....

 

[jburnes]

rjones,

I'm with ya. Have you had your fuel pump timing checked yet. I'm hearing it should be set at 15 degrees +-. Those reading this please reply, if your getting better than 20 mpg could you tell me what your's is set at. Those with better than 25 mpg what's your timing set at? My bombed stuff is set-up right, but 16 mpg is tops for me. I have not checked the timing--That's next, but setting the Fuel Pump timing is critical. . Help!! 15,15. 5, 16, 14, 14. 5 degrees... HUH? What best?

JB

 

[rjones]

Originally posted by jburnes

rjones,

I'm with ya. Have you had your fuel pump timing checked yet. I'm hearing it should be set at 15 degrees +-. Those reading this please reply, if your getting better than 20 mpg could you tell me what your's is set at. Those with better than 25 mpg what's your timing set at? My bombed stuff is set-up right, but 16 mpg is tops for me. I have not checked the timing--That's next, but setting the Fuel Pump timing is critical. . Help!! 15,15. 5, 16, 14, 14. 5 degrees... HUH? What best?

JB

I set mine this past summer to 16 deg but I think it might ahve slipped... ... . Its alot less noisy and there is less smoke... .

 

[Mike Ellis]

Another thought, may be relevant to a few. If you have a stock truck with catalytic converter and haven't driven it hard or towed in a while, perhaps the thing is somewhat plugged up and restricting flow.



I pulled a heavy load of heifers today, first real workout in a couple of months, and a LOT of gunk came out the tailpipe when I started working it. My truck won't emit the famous "black clouds" like the BOMBed guys do, so it was very noticeable difference from usual operation.



May be my imagination, but it sure seems to run better after a good workout. I have seen other posters mention this also so maybe I am not completely crazy here.....

 

[jburnes]

Cat

Mike, I took mine off right away. I now have a 4" turbo back Rip Rook system. I also got rid of my EGR (CA) and built and intake!

Timing is next. I picked up 2+ mpgs on my first tank with the new intake (18. 5mpgs). It spools up so quick now! 285's, auto, 2500, 3:55's, Bank's Sting +, remote transmission cooler

 

[Mike Ellis]

jburnes,



Looks like you are on the right track, that's a nice improvement! Let us know how the timing works out...

 

[Reddog1]

Have you guys noticed that you could hear a pin drop when you ask the high MPG guys how they do it?



I guess I am in the "slinger bashers" group. Some of the post should start with "Once upon a time... ”



I really appreciate post like those made by JJW-ND, rjones and a few others. Agree or disagree, they offer support for their thoughts.



Some folks should make fewer statements, and ask more questions.





Wayne

 

[Sled Puller]

Originally posted by Reddog1

. Even if you just consider 17 to 23 mpg, that is a lot.

:

“my truck was getting 18 MPG. I made the following mods and now get 24 MPG”. I want to see how it is done. Respectfully, the mileage claimed by some, would be easier to believe. "

1997 California emissions truck, 5 speed, long bed ,club cab, 3:54 ratio, stock tires, 180 hp engine.

16-17MPG.



Removed California emissions, 300 injectors, 16 housing, 16 timing, #5 plate.

Best of 22. 7 mpg, average about 21. 5.



Since then, extensive mods, dropped back down to average 18mpg.

I think bewteen 275 and 350 is the sweet spot for 12 valves.



I knew of one guy with a first gen personally, who claimed 27. When pressed for more details, he checked it on a long stretch of highway, slight down hill grade with a tail wind!!!



Driving habits are huge when checking mileage.

 

[Reddog1]

Sled Puller - I think the 27-MPG guy posted here.



From 16-17 MPG to 22. 7 mpg is very impressive to me. Did you make all the mods (for the 22. 7-MPG) at one time?



My son bought a 98 12v recently. He drives much slower than an old man does. He thinks stock has enough power, but would like to increase his 18-MPG.



Before mods, I was getting 18 to 19 MPG. After mods, I get 17 to 18, and it does not take much to get 16 to 16. 5 MPG. I have 15 degree timing, 370 (Piers) injectors, 3k gov springs, #10 plate and a complete DTT trans. I think I get spasms in my right foot. That would explain the 16 to 16. 5 MPG.



Bye the Bye, from what I read if you replaced the injector hole to injector line adapter with injectors, you might get the 22. 7-mpg back. LOL





Wayne

 

[Sled Puller]

naw, my 27 was a different guy, ,lol.



Yep,all the mods were at once.



I was fanatic about watching mileage back then. When I went to 370s, then bigger Dvalves, the mileage started slipping.

That set -up I mentioned was virtually smoke free, and you had to really be stupid to get an unreasonable egt.



Someday, I would like to turn the fuel back with my twins, just to see what kind of economy it could get. I think it could do better than 22, but who wants to do that?

 

[Reddog1]

As I previously stated, I have 15 degree timing, 370 (Piers) injectors, 3k gov springs, #10 plate and a complete DTT trans.



I have considered stepping back, instead of chasing the EGT's.



I see so many false claims, I am hesitant to believe most of the post, especially when they cost me money.



I would like to try a set of 215 injectors.





Wayne