smokdya

iTrader: (10)

I just got through rebuilding my 2000 LS1 engine for my TA. The rebuild included a 228/228 cam .588 113 lsa, new rings on stock pistons, new crank, 90/90 Fast/NW setup, push rods, comp trunnion rocker upgrade, 243 heads, headers, PAC 1518 springs, and a textralia clutch. I was getting around 24 mpg before the rebuild, but now I get somewhere between 14-16 and it seems to get worse every time I check it even though I am driving it a little easier. I actually hit 16 the first time I checked it and 15 the second time I checked it and now I am at 14. It is a m6 and I shift around 1500-2000. I upgraded to stainless bolts when I put the intake on, but I noticed that I did have a few of screws that managed to get loose. That was the only thing that I didn't use loctite on b/c an older guy was telling me they are bad about freezing in the threads when they get hot. I will be putting the stocks back in or loctite on these before it's over with. I didn't know if this could be the cause or if 14-16 is normal. This is a dd and I went with this cam b/c I thought I had seen that I should only loose 3 or 4 mpg. I am going to try and catch up with the tuner to see if he can do something on his end. Just let me know what you think. Any advice or suggestions is appreciated. -Thanks

usafws6

iTrader: (10)

thats about what mine is, gas mileage goes down the drain with a cam.

DBurgLT1

That's not necessarily true.

MeentSS02

iTrader: (11)

Moving this to Gen III Internal Engine.

Darkman

iTrader: (2)

Based on my own experience I think there is a problem.

As I have added high flow cats, heads, a cam (baby EPS), a FAST intake and tunes as necessary, my highway gas mileage has improved over OEM slighty and my city gas mileage has gotten no worse. This is based on calculated mpg numbers based on tankfuls as opposed to readings off an instaneous fuel consumption guage.

I can, of course, acheive single-digit mpg levels with a lot of spirited driving.

madden

iTrader: (2)

Seems pretty low to me. Give me a call when you have some time and we can talk. Does the car still run fine at WOT?

FiredUpZ28

F body fuel economy ratings for an auto at least is 17/24 - so if you're getting 17 city and it drops 3-4 mpg....... You could always take it back to your tuner and see if he can't lean it out a bit part throttle.

smokdya

iTrader: (10)

WOT is great! I have no complaints there. If I need to sacrifice some of that though, I am cool with that.

I was getting around 24 back and forth to work before I did the swap . That's why I am curious what could be making it so low, b/c now the same trip is at 14 which is a 10 mpg loss. I am going to try and set something up with Jason @ MadTunes Racing to see if he can do something with it.

slt200mph

iTrader: (42)

When mine was bone stock it got 28.5 on the highway and 21 around town...I have had 3 different cams and the car is a heads/cam all the bolt ons...after all the mods it gets about 27 on the highway and 19 around town...if you are down 10 mpg I would think that there is a problem...mine is a 6 speed...are you running a high stall converter... if so that can change your fuel consumption.

cutlass_455

iTrader: (2)

Whats the oil look like?? Im wondering if the rings didnt seat properly and you are getting lots of blow by or something. Did you break it in 'properly'??

smokdya

iTrader: (10)

I haven't thought of that. I used the break-in procedure that was supplied with the mahle rings that I bought. I will give the oil a closer look this evening.

madden

iTrader: (2)

I believe the problem is now solved There was a bad 02 sensor in bank 2 and after replacing it he's now reporting over 20 mpg on initial tests.

smokdya

iTrader: (10)

Sorry..forgot to post back to this thread. Jason at MadTunes (aka "Da Man") and I messed with my car a little on Saturday morning. It was found that there was a bad 02 sensor in bank 2 after playing with a few line graphs. On the way home, I picked up a new O2 sensor and stuck it in there. I filled up and made about a 30 min trip and checked the fuel mileage and it was almost to 20 and that was with some city driving. I think I will be back above 20 on my drive back and forth to work again. I am happy and so is my wallet. Thanks again for all the suggestions.