Yes I've searched, but nothing answered my question so here it goes.


Right now my car is 100% stock, except for the K&N drop-in filter. Everywhere I need to go, I take the local streets because that's all I really need to take (nothing more than 5 miles away). I'm getting a pathetic 13-14mpg in the city, and I basically take local roads. Once every blue moon (a month or so) I use the freeway, but only for about 5 minutes that I'm actually on it. Everyone knows Southern California is horrible when it comes to going to A to B without interuptions.

Constantly I accelerate and stop because of the stoplight, and because there are people who can't drive (ie. drivers 35mph in a 45mph zone). Rarely does my car cruise and if it does, it's only for 10 seconds or so.

I know people get worse gas mileage with the 3.76 gearing, but in my case, I think it helps because my car then requires less effort to get up to speed. People lose highway gas mileage because the difference in engine speed when cruising over a period of time. So really, the gearing should help me when I'm accelerating, but I wont be cruising for long, so theoretically, it should help with my gas mileage correct?

Any input would be appreciated.

 

Well, I just put in my RMM 3.76 LSD about a month ago and my gas mileage has averaged 15 MPG. I drive city stop and go about 95% of the time. I was getting about 17 MPG before the new gearing. Now I don't know if the reduction in mileage is do to the gearing or to me punching it all the time . If you are only getting 13-14 MPG in the city, you may need a plug change, fuel injector cleaning and throttle body cleaning. Or just lay off the quck starts .

 

I drive like a grandpa. I think it's more because of the traffic here.There is a red light every 15 seconds or so. Plugs and everything are up to date. I recently did an oil change also. I might do the throttle body cleaning, then again, I highly doubt that is the problem. I am currently cleaning the engine with Auto-RX and have put in Seafoam into my gas. Hrm...

BTW, is the RMM differential your only performance mod? If so, was acceleration that much better? My car (GS400) feels laggy down low. I would have to punch the throttle just to get the transmission to downshift. I dont want to have to punch the throttle everytime I want to pick up some more speed.

 

where do you get seafoam? you put it into your gas? i thought it was some kind of detailed cleaner that you needed to put into your engine and other small inaccessable areas and have it flushed out?

 

I had the 3.76 gears awhile ago...I was averaging around 24 mpg on the highway before... then after, I averaged around 19-20mpg... so i switched back to the stock diff. I hope to get the TRD diff one day.

 

See, this is completely opposite of me though. I do basically no highway driving. I am constantly accelerating. I figured if the engine needs less effort to get up to speed, I'll get better gas mileage since I'm almost never cruise. Oh well.

 

You Autozone should have it.

You can put it in your gas, oil, or through the intake system. I already have Auto-rx in the oil, so I dont think it's a good idea to mix another treatment. I haven't run it through the intake yet, as I have ran out. Maybe i'll do it some other time.

 

I do more highway miles ( 60/40 ) - but my experience is about 1 to 1.5 mpg less with the 3.76. Still worth it for me though - much better response.

 

Well I do have a Borla exhaust and K&N drop in filter. However, the 3.76 gearing will make a huge difference in your off the line acceleration. The car just responds much better with the quicker gearing. The LSD is great when making turns and accelerating. With the stock diff and the VSC on, if the wheels slipped at all the car would basically shut down. Now if I do that and the wheels slip a bit the VSC may come on but does not shut down the car like before. I just think the car is just way better with the revised gearing. It does hold onto gears much longer than before, especially 3rd. The lagging type feeling you are having now is a result of the crappy gearing. You will all but eliminate that feeling with the 3.76 gearing. It is one of my favorite mods so far. I would have most likely gone with a torque convertor first if I did not have a 2001 car due to the possiblity of the check engine light. The 3.76 gearing is probably the best modification to make your car more responsive to throttle input.

 

For the 1st time since having my 3.76 installed, I took a long road trip and determined that I only averaged 20 mpg. This was running at 75 to 80 mph with the air on, 3 people + 3 suit cases.
Although the 3.76 killed my hwy mpg by about 3 to 4mpg, I'm going to keep the 3.76 in since the trade off in performance is well worth the extra gas.

 

No, I don't think so. Your car is at higher rpms all the time while moving with the 3.76 gearing and that will consume more gas.

But you paid a bundle (I assume) for the LSD and install - worrying about a few $ on gas doesn't seem rational.

 

- I agree completely! It's awesome.

 

Just got mine in yesterday......and everything you read from other members regarding driveability, shift points and acceleration is all true. My biggest beef with the GS before this mod was that I always thought the car felt bogged and shifting to early. This is the way it is supposed to feel now that the 3.76 LSD is in.

 

Amen brother!

 

congrats!

You have the PI TC as well?