xtremerevolution Posted May 18, 2011 Report Share Posted May 18, 2011 For those who unaware, this is a factory tune. I personally think that's a big problem. Your increase in compression effectively drops you 2-3 pulley sizes. Aftermarket top swap kits come with a 4.1" pulley iirc. Sent from my HTC Awesome using Tapatalk Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 18, 2011 Report Share Posted May 18, 2011 Those DICs are never accurate! What he said. I have a 2000 regal gs and that dic is pretty inaccurate. Its a nice thing to look at, but I usually just calculate my average at the pump based on my trip odometer. That being said, slowing down will add a good 3mpg, and following a big vehicle will add more as well. I take that kind of advice to heart on road trips. Sent from my HTC Awesome using Tapatalk Link to comment Share on other sites More sharing options...
Jonpro03 Posted May 18, 2011 Author Report Share Posted May 18, 2011 (edited) .. Edited May 18, 2011 by Jonpro03 Link to comment Share on other sites More sharing options...
urbex Posted May 18, 2011 Report Share Posted May 18, 2011 What he said. I have a 2000 regal gs and that dic is pretty inaccurate. Its a nice thing to look at, but I usually just calculate my average at the pump based on my trip odometer I agree with that! Just today I checked the mileage in my HHR to compare to the DIC, and the DIC read 1.5mpg lower than actual.... You think after all these years they could get it to calculate accurate...oh well. Link to comment Share on other sites More sharing options...
94 olds vert Posted May 18, 2011 Report Share Posted May 18, 2011 The DIS in the cutlass is very accurate for fuel used and MPG. Link to comment Share on other sites More sharing options...
WhatTheFehl Posted May 18, 2011 Report Share Posted May 18, 2011 I agree with that! Just today I checked the mileage in my HHR to compare to the DIC, and the DIC read 1.5mpg lower than actual.... You think after all these years they could get it to calculate accurate...oh well. The estimated average fuel economy on the DIC in my GP is actually pretty darn accurate Link to comment Share on other sites More sharing options...
Jonpro03 Posted May 18, 2011 Author Report Share Posted May 18, 2011 (edited) .. Edited May 18, 2011 by Jonpro03 Link to comment Share on other sites More sharing options...
virtuetovice Posted May 18, 2011 Report Share Posted May 18, 2011 There are too many variables to be able to achieve 100% accurate fuel economy calculations...at least with minimal-cost hardware. I've seen wrist watches with more processing power than a driver info center... There are endless things that effect fuel economy in minute amounts and they all add up. Link to comment Share on other sites More sharing options...
Jonpro03 Posted May 18, 2011 Author Report Share Posted May 18, 2011 (edited) .. Edited May 18, 2011 by Jonpro03 Link to comment Share on other sites More sharing options...
mra32 Posted May 18, 2011 Report Share Posted May 18, 2011 Installing one of these will give you AMAZING fuel mileage. Link to comment Share on other sites More sharing options...
88red4cyl Posted May 18, 2011 Report Share Posted May 18, 2011 Hm... The DIC in my Monte is spot on if you remember to reset it at the fuel up.. I just used it on our trip to St. Louis last weekend, and it said exactly what I figured with my phone... If you don't clear it every time though it isn't accurate... Link to comment Share on other sites More sharing options...
Night Fury Posted May 18, 2011 Report Share Posted May 18, 2011 The one in my 04 is pretty damn accurate as well. Never more than 1 mpg off. Link to comment Share on other sites More sharing options...
carkhz316 Posted May 18, 2011 Report Share Posted May 18, 2011 Don't draft, especially truckers. Geesh. Dangerous and annoying. Link to comment Share on other sites More sharing options...
Jonpro03 Posted May 18, 2011 Author Report Share Posted May 18, 2011 (edited) .. Edited May 18, 2011 by Jonpro03 Link to comment Share on other sites More sharing options...
urbex Posted May 18, 2011 Report Share Posted May 18, 2011 One thing I wouldn't like about following a truck is the stone chips. Link to comment Share on other sites More sharing options...
RobertISaar Posted May 18, 2011 Report Share Posted May 18, 2011 for OBD1 at least.... DICs calculate fuel usage based off of a running total of the fuel injected in mSec, distance traveled according to the 4K PPM signal, and injector flowrate in GPH. now, since the running total of fuel injected is a self-generated value from the PCM, that value is never a problem unless the injectors open/close slower than anticipated. but, if the 4K PPM signal the ECM generates based off of the VSS signal is innacurate(tire size difference will do it), that will cause inaccuracy. possible problem #2 is injector flowrate, if they flow more or less than the value that is calculated and stored in the PCM, that will also cause problems. a FPR that doesn't work as desired can cause this. Link to comment Share on other sites More sharing options...
88red4cyl Posted May 18, 2011 Report Share Posted May 18, 2011 There is nothing dangerous or annoying about this. ^^^ Tailgating would be dangerous, but not drafting. Nothing wrong with that.. I think they're referring to your comment that you follow at 1.5 car lengths (which is less than the pic shows)... Link to comment Share on other sites More sharing options...
RobertISaar Posted May 18, 2011 Report Share Posted May 18, 2011 that's about 1 1/2 limo lengths IMO. also, i went and looked up a 99 GTP's DIC, and it also uses the 4K PPM signal in addition to the UART link, so there's a pretty good chance that the OBD2 DICs work exactly the same as OBD1. Link to comment Share on other sites More sharing options...
Dark Ride Posted May 18, 2011 Report Share Posted May 18, 2011 Don't draft, especially truckers. Geesh. Dangerous and annoying. Until I had to drive a roughly 46' RV that was alot more like a truck than an RV, I never appreciated how annoying having someone draft you is, if I have to turn on the backup camera to find you, you are too close. If you can't see their mirrors, they can't see you. Link to comment Share on other sites More sharing options...
Jonpro03 Posted May 18, 2011 Author Report Share Posted May 18, 2011 (edited) .. Edited May 18, 2011 by Jonpro03 Link to comment Share on other sites More sharing options...
white4d96 Posted May 18, 2011 Report Share Posted May 18, 2011 I check my mileage at every fillup using the trip meter as well Jon. Link to comment Share on other sites More sharing options...
RobertISaar Posted May 18, 2011 Report Share Posted May 18, 2011 if i had to guess..... then i'd say that the DIC constantly keeps storing trip MPG rather than a mileage based value. after so many trips, the oldest one gets pushed out, and the new one gets filtered in, etc.... Link to comment Share on other sites More sharing options...
88red4cyl Posted May 18, 2011 Report Share Posted May 18, 2011 I think that the largest margin of error comes from the human aspect. The DIC is computing the last 2k or so miles and we only compute the last couple hundred.I don't know about anyone else, but I reset the trip when I get gas. Then divide the miles driven by the amount of gas I just put in (to full). I don't continuously add the amount of gas that I've added since the last time I reset the DIC. I've also noticed that the DIC only stores so much information before deleting the overflow. I'm not sure how much information it stores, but it seems to be close to 2k miles worth. I would be interested to find out what that number is, although I'm sure it's a memory size number and not a mileage number... Can you not clear the avg MPG on the 2nd gen DICS? Then it only stores what youve done since you cleared it, at least thats how the 3rd gens are... Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 18, 2011 Report Share Posted May 18, 2011 If you were unaware, that is an insult. A baseless and incorrect one at that. Don't think that just because I'm holding my tongue that I don't have anything to say to you. Jon, you have a 3500 with warped heads after having blown a few head gaskets and admitted the first time the gaskets blew that the tune was completely off. We looked at your tables over on gmforum and couldn't believe how bad they were, and you can't entirely blame megasquirt's auto-tuning on that. Those tables were off the charts. You have a top swapped 3800 on a higher compression engine and absolutely nothing past the stock tune and you fail to realize there's a problem there. Stock tune on a top swap is a terrible tune. That's not baseless. A top swap on a higher compression N/A 3800 engine is nearly the same as running a 3.4" or 3.5" pulley on an L67. I run a 3.4" pulley and I have headers, CAI, exhaust, colder plugs, 180 t-stat, a tune, and hood vents to lower under-hood temperatures. You have none of those, and no tune. ZZP *recommends* a 4.2" pulley if you're on a base tune. Milzy Motorsports' top swap kits comes with a tune specifically for the top swap. Base tune on a top swapped L36 with a 3.8" pulley = bad tune, I don't care who you ask. On top of that, you run 87 octane. There are so many things wrong with that scenario that I don't know where to start. I really don't know of any way to say what I've said nicely. If you have something to say to me, say it, but I'm not creating drama here. If I think you're giving bad advice, I'll mention it, and there's no reason to get offended. Chalk it up as a learning experience. I stated quite clearly in my first response what I didn't disagree with, and many of those points came from more people than just myself. You seriously can't go around telling people to run 87 octane in an boosted or high compression motor and over-inflate their tires (to result in uneven tire wear), and expect people to agree with you, and then back up all your numbers with a DIC reading of questionable accuracy. Now if you had said, I filled my tank, drove X miles, filled up X gallons after the tank emptied, and got X MPG, then changed all these values and got X MPG increase, that would be a different story, but you gave bad advice and used an unreliable and inaccurate way to measure your claimed improvements, and I pointed out the errors in your advice and others have pointed out the errors in your metrics. I know you don't like me because I didn't apologize like you profusely demanded that I do to the kid I flamed for racing 100mph+ in his stock 92 lumina and endangering his life and the lives of others around him, but this has nothing to do with it. I would have responded to anyone's post in exactly the same way, so don't take it personally. One thing I wouldn't like about following a truck is the stone chips. This brings up a good point I hadn't even thought of. You run a good risk of having something big flying into your windshield. Link to comment Share on other sites More sharing options...
xtremerevolution Posted May 18, 2011 Report Share Posted May 18, 2011 I check my mileage at every fillup using the trip meter as well Jon. I've found that to be the only truly accurate way to determine your fuel economy for a given tank of gas. Take enough of those measurements on enough tanks of gas, and you get a good long-term average. if i had to guess..... then i'd say that the DIC constantly keeps storing trip MPG rather than a mileage based value. after so many trips, the oldest one gets pushed out, and the new one gets filtered in, etc.... I have noticed this behavior on my Bonneville GXP as well as on my Regal GS. Were this not the case, after some time, your fuel economy would very rarely change. Can you not clear the avg MPG on the 2nd gen DICS? Then it only stores what youve done since you cleared it, at least thats how the 3rd gens are... You can clear it, but my experience with two bone stock motors is that they are still inaccurate by as much as 3 mpg. Link to comment Share on other sites More sharing options...
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