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6.5L IP+ATT

Yeah, it does. It feels like it pulls a bit harder past 2500rpm. My low end is what i am most impressed with. Before I had to rev 1st gear up to about 2500rpm to get it to shift into 2nd comfortably without smoking too much. now I can shift at 1900rpm into 2nd and it pulls right into gear with no smoke at all. You guys have helped more than can be thanked, and I appriciate all the feedback. i know I am new here but I definately plan on being a consistant reader and try to be as helpful as possible. thank you all for everything
 
On the timing - this site can explain why you get less smoke. Advanced smokes. Smokes worse with a turbo because there is less heat given to the turbo with high advance. You can also watch the smoke when the cold advance is on go away the instant it kicks off. I am usually under load when it does and see the smoke go away.
http://www.oliverdiesel.com/tech/timing.htm
 
Ok, so i read that article on timing on that site you linked over too WarWagon. So if I retarded the timing slightly like I did, i should be getting less smoke. and smoke did go down. But I am kind of lost on it a bit. Does retarding the timing, although visible smoke goes down, actualy cost me fuel mileage? Maybe I was just reading it wrong, timing isnt something i very well understand so it is kind of a concept in my head. Any idea's? haha
 
No it wont cost you fuel mileage until you go too retarded. You were too advanced. In general these engines like a good amount of advance and some people clear up smoke and get more power by advancing. Its just for different reasons. You just happened to be way too advanced.
 
You guys really are life savers haha and I did a mileage test over the last 2 days. A decent amount in town driving and mostly highway. Overall round trip was 193 miles. Before I was getting around 17.5-18mpg and now I am up to around 19.5-20 since retarding the timing. Overall thats really good considering I was at 21.5-22 when I first got the truck. Turning up that fuel really took a digger on it lol I think with the ATT I should be able to get back somewhere near that 21-22 mark. I am confident. and earlier we were talking about the fuel delivery and such of the DB2 vs DS4. You said the DB2 doesn't have as much fuel as the DS4. Does anybody have the ballpark specs on how a DB2 with 1/4 turn measures up against a chipped DS4? as far as cc's of fuel. What can a DB2 put out for fuel as far as possibly a half turn? and with the fuel screw bottomed? again as far as cc's of fuel. Just wondering about some ballpark figures here haha Because I can keep right up with two DS4 equipped trucks. the one is stock and I can beat it everytime and the other has a chip, exhaust, TM, and an intake, and I can keep right up next to him, even with having to shift. Theoreticly shouldn't he be walking circles around me? haha
 
6.5L said:
Just wondering about some ballpark figures here haha Because I can keep right up with two DS4 equipped trucks. the one is stock and I can beat it everytime and the other has a chip, exhaust, TM, and an intake, and I can keep right up next to him, even with having to shift. Theoreticly shouldn't he be walking circles around me? haha
Click to expand...

The DB2 can be modified to output quite a bit of fuel, 90-100mm3, comparable to the DS4 when properly coerced. I think the DB2 has a range of about 2500-3000rpm for max fueling, which before and after it falls off pretty quickly. Stock plungers and everything, when turned up all the way the DB2-4911 probably outputs 70-80mm3. However, the DS4 can output more fuel earlier in the RPM range than the DB2 can, for those towing at 2000-2500rpm. And the DS4 timing can be manipulated at any RPM or fueling range. As NVW stated not all chips are created equal, and neither are all intakes, exhausts, ect....The standard tranny will help you as well and the 4.10 gears are ideal for racing.
 
Ok. That makes sense. And what modifications are nessasary for the fueling you mentioned earlier? I take it the internals have to be changed. What does a chipped DS4 output for fuel? just a ballpark figure. and earlier Slim said something about a side arm advance or something. Do you know what that is? and he said about increasing case pressure that advances timing through the whole rpm range, isn't that what advancing or retarding the timing does? or is it something completly different? he also said do it at your own risk. What are the pro's and con's of it
 
Really? maybe mine is just weird and is suppose to get bad mileage haha it seems weird that with 4:10's I was capable of getting up around 21 highway. Even after the fuel turned up and the timing issue fixed I am sitting fairly comfortable on 20mpg. I thought when I bought it the 4:10's would kill mileage but apparntly not. Maybe it's because I have a manual transmission. A buddy of mine here has a 1993 with a manual and he said he's getting 19-20. He also has 4:10's. Seems weird. Maybe the 6.5 god did skip one haha maybe it's elevation. I am not sure if it affects a diesel like it does gas, but I'm sitting at around 5,100 ft above sea level. I got to thinking though and I never contemplated weather the previous owner had turned up the fuel any in the pump. Maybe I am sitting past 1/4 turn? I did think of that today. and a mark of acheivment, just crossed the 365,000 mile mark yesterday, all original motor haha I am aiming for 400,000.
 
Mine has a 5 speed, 4x4 235/85 tires, dually, and 4.10's. Maybe the flat bed, duals, and 4x4 make that much difference? Mine has 216K on it.
 
Really? It must be the duallie. I am not sure. I have 265/75/16's. I think that's a bigger tire. Maybe that keeps my rpm's down enough to warrant a difference, but not a 4mpg difference. Could be the duallies. With a taller tire in theory, it should take a little bit more power to get it going but once it is going, it should want to keep it's rotational momentum better than a smaller tire, making it easier to run highway. Is't that what high school physics taught us? haha I run 2,200rpm at 60. Peak torque I hear. I will have to wait until I throw her on G&J's dyno to know for sure though
 
Oh I see. I am not a whiz on tires. Thanks for the clarification haha Buddy how did you like your ATT?
 
I like the ATT, the engine is much stronger and happier at 2500+ rpm and if your cruise at 2200rpm and up it will probably help efficiency a little.
 
WarWagon;348083. [url said:
http://www.oliverdiesel.com/tech/timing.htm[/url]
Click to expand...
Argh error 404 - page not found

That's an intersting thread. Iknow a guy working on resurecting his old 1982 Jimny, replacing his 6.2 by a 6.5
As he is looking for the wildest 6.5 possible, he's watching at an A-Team coupled to a DB2... and marine injectors.
 
My tach read 2200 @ 65??? speedo is correct according to GPS but i keep for getting to compare GPS trip to trucks trip meter to see if the readings are close or if I need to figure out a % error to adjust by.
 
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