xtremerevolution Posted October 5, 2009 Report Share Posted October 5, 2009 don't be fooled by marketing. the supercharged engine has a higher compression and requires higher octane fuel to prevent predetonation. you put regular in there, and the car has to retard the timing to prevent that, thereby reducing your combustion efficiency and therefore reducing your gas mileage. A series 1 3800 will get less peformance with premium fuel because its harder to detonate on its low compression engine. I have one and have driven it for almost 150k miles. I've tried all types of fuels. Quote Link to comment Share on other sites More sharing options...
MonteCarloChick Posted October 5, 2009 Report Share Posted October 5, 2009 lol I'm so sick of this argument. People are stubborn about it and just won't listen to facts. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted October 5, 2009 Report Share Posted October 5, 2009 lol I'm so sick of this argument. People are stubborn about it and just won't listen to facts. X87 Quote Link to comment Share on other sites More sharing options...
Euro Posted October 5, 2009 Report Share Posted October 5, 2009 the supercharged engine has a higher compression Actually the NA 3800 has a higher compression Quote Link to comment Share on other sites More sharing options...
Andrew Posted October 5, 2009 Report Share Posted October 5, 2009 BACK ON TOPIC GUYS Do this and report back. Go through the standard items. Spark plugs/wires Air filter O2 sensor Fuel filter MAF sensor (needs cleaning?) Dragging rear brakes/park brake cable Ever done seafoamed the car? That alone boosted a guy 4MPG here in a similar fuel economy thread a week or so ago. Just scroll down some in this section and you'll find it. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted October 5, 2009 Report Share Posted October 5, 2009 Correct, the pistons provide a lower compression on the L67 than on the L36, but doesn't the boost increase compression? Quote Link to comment Share on other sites More sharing options...
slick Posted October 5, 2009 Report Share Posted October 5, 2009 No. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted October 5, 2009 Report Share Posted October 5, 2009 No. static compression, no dynamic compression, yes Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted October 5, 2009 Report Share Posted October 5, 2009 dynamic compression is what I was referring to. just didn't know the name for it. Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted October 6, 2009 Report Share Posted October 6, 2009 so this past tank of gas I figured i'd go easy on the car. I'm a field technician for work, so I drive all across the city. I'd estimate 75% highway and 25% city and stop and go traffic. On the highway I kept it at 70-75mph. I pumped gas at a 76 gas station (phillips conoco), and calculated 25.96 mpg. Not bad for a 208k mile 3800 huh. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted October 7, 2009 Author Report Share Posted October 7, 2009 I got 15 again this time on 89 octane. Next I'll run some 87. The air filter is newer, and everything else is clean or new except the o2s. I'll have to pick up a set and try that next. Oxygen sensors aren't too cheap but if that fixes it the fuel savings will pay for them and then some. Also need to pick up some seafoam and piss off the neighbors more than usual. Quote Link to comment Share on other sites More sharing options...
Masterchief362 Posted October 7, 2009 Report Share Posted October 7, 2009 I got 15 again this time on 89 octane. Next I'll run some 87. The air filter is newer, and everything else is clean or new except the o2s. I'll have to pick up a set and try that next. Oxygen sensors aren't too cheap but if that fixes it the fuel savings will pay for them and then some. Also need to pick up some seafoam and piss off the neighbors more than usual. The 02 helped my moms MCSS increase mileage a bit by replacing. And she runs ethanol blended 87 from Express and gets an average of 25 with 50% highway. What I found amazing was having 4 people in the car, full trunk of luggage, and 80mph average on the interstate and got 32mpg. 3800's can be amazing when it comes to fuel economy. Oh and seafoam does wonders. Did it on my 3100 for the first time at 125k miles, and damn I filled my entire street with smoke... gave me an extra 2mpg overall though. Good luck with your car. Quote Link to comment Share on other sites More sharing options...
Night Fury Posted October 7, 2009 Report Share Posted October 7, 2009 I can't WAIT to seafoam the monte... Should make for quite the show Quote Link to comment Share on other sites More sharing options...
xtremerevolution Posted October 7, 2009 Report Share Posted October 7, 2009 I got 15 again this time on 89 octane. Next I'll run some 87. The air filter is newer, and everything else is clean or new except the o2s. I'll have to pick up a set and try that next. Oxygen sensors aren't too cheap but if that fixes it the fuel savings will pay for them and then some. Also need to pick up some seafoam and piss off the neighbors more than usual. Yeah, I would just bit the bullet and buy a pair of oxygen sensors. Well worth it considering how much of a difference they can potentially make in regard to fuel economy if they're bad. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted October 8, 2009 Author Report Share Posted October 8, 2009 Front O2 and Seafoam in a bag in the car now. I just assumed there would be 2 front O2s but there is just the one where that cross over pipe comes into the even side manifold. Glad it only cost $52, instead of $104. Quote Link to comment Share on other sites More sharing options...
Imp558 Posted October 10, 2009 Author Report Share Posted October 10, 2009 Did some reading last night and I had to post a link to this guy's experience with Seafoam. I laughed HARD! The good part is in the 4th paragraph: http://volvospeed.com/vs_forum/index.php/topic/47450-seafoam-billowing-white-clouds-of-smoke/ Quote Link to comment Share on other sites More sharing options...
Imp558 Posted October 10, 2009 Author Report Share Posted October 10, 2009 20 MPG here I come! Did the Seafoam, and a more thorough cleaning of the MAF (scary fragile looking), and made a ghetto exhaust scrubber to minimize the smoke and it worked. Once the car cools down I'm doing the front O2, cleaning out the throttle body, and another new air cleaner element. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted October 10, 2009 Report Share Posted October 10, 2009 what exactly am i looking at? i see a bucket and what looks like two pipes entering/leaving the top of said bucket... Quote Link to comment Share on other sites More sharing options...
Imp558 Posted October 10, 2009 Author Report Share Posted October 10, 2009 A bucket full of water. A real scrubber like in the smoke stack of a factory has jets that mist water into them and catch particles before they can escape. My bucket water got a little dirty but there was very little smoke like others had reported. Quote Link to comment Share on other sites More sharing options...
AL Posted October 10, 2009 Report Share Posted October 10, 2009 I havent done the seafoam in the vacuum lines yet but I plan to here shortly... What lines are used when seafoaming a 3800, how about a 3.4? Quote Link to comment Share on other sites More sharing options...
Imp558 Posted October 10, 2009 Author Report Share Posted October 10, 2009 I used the one to the brake booster. I put a piece of tubing into it and dunked the other end 1/3 of the way into the can of Seafoam and then used my hand to close around it so it sucked it up like a drinking straw. Quote Link to comment Share on other sites More sharing options...
Radnsmash Posted October 10, 2009 Report Share Posted October 10, 2009 I can't WAIT to seafoam the monte... Should make for quite the show Me either! Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted October 10, 2009 Report Share Posted October 10, 2009 I can't WAIT to seafoam the monte... Should make for quite the show Me either! i only got a gigantic cloud of smoke the first time i ever did it... lasted for 20 minutes of parked reving/idling, but i'm always disappointed when there isn't as much shit being burnt off... at least i can take comfort in knowing the motor was fairly clean to start with... Quote Link to comment Share on other sites More sharing options...
Imp558 Posted October 10, 2009 Author Report Share Posted October 10, 2009 I guess in theory my ghetto scrubber may not have done anything. It could have just been that it didn't smoke a bunch? I felt better about it because I live in a very small suburban borough where I'm the only gearhead and they don't approve of my (insert here) already. Quote Link to comment Share on other sites More sharing options...
RobertISaar Posted October 10, 2009 Report Share Posted October 10, 2009 I guess in theory my ghetto scrubber may not have done anything. It could have just been that it didn't smoke a bunch? I felt better about it because I live in a very small suburban borough where I'm the only gearhead and they don't approve of my NUDIST ACTIVITIES already. possible..... Quote Link to comment Share on other sites More sharing options...
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