Hey fellow thirdgenners!

I have a stock daily driver LO3 RS. I get 25 MPG all day long highway/city. But it really needs some mods/gears to wake it up. My question to you all is:

What mods/gears do you have?
What's your MPG?

Thanks!

 

< mods are right there. also have a very good tune. i get 16-18 city, and 24-26 highway with the 6 speed and a heavy foot

 

Ok I get like 22 city and I have clocked over 30hwy on my 92 L03 5spd with the 3.08 rear. But there are some things I have found to increase mileage on my Monza but they are about as useful to you as a honda part but they work out.

I removed all emissions ( I know its illegal but for the sake of science) , sealing off the EGR valve, removed the cat, and advanced the timing a little.

Your engine is a pump so make it more efficient by making it work less. I removed the mech fan and replaced it with electric, removed the smog pump, and ported and polished the intake, head, and exhaust to match the gaskets. Also upped the rocker arms to 1.6 for a little more flow and unshrouded the valves.

The monza came with a holley 2bbl progressive carb so I replaced it with a Webber 32 progressive carb and installed a air-fuel guage and tuned it to run a little lean untill the 2nd barrel opened. You can get EBL and do this with a laptop and like 20min this took me days to get a perfect tune so embrace technology.

Also get a nice free flowing exhaust because it is always nice to have reguardless of your goal well unless you wanna keep it stock but I doubt thats the issue.

My monza had the original iron duke (4cyl) and with 70 profile tires on 13 rims with a 2.73 rear and a th200 (3spd auto) stock got 20/27, after mods I was getting about 42/52 and at best 48 city but I lost to much power and overheating became a problem.

Get
EBL (tune all your worries away)
Free Flowing exhaust
Better heads
180 thermostat (tune fans to match)
3.08 or lower gear
and a taller tire wouldn't hurt

There are hyper milers getting really insane numbers but they are all in hybrids but still nothing to laugh at about a Prius getting 200+mpg, granted when you get a camaro in the 10's we can pass everything but a gas station.

 

Top 3 upgrades for our Lo3's

#1 Heads
#2 Exhaust
#3 Tune

Gears are a given benefit.


Probably get the most power out of those 3 things, Wish I could get as good mpg as you guys do.

 

excuse me but how the hell is throwing out the EGR system supposed to give you a GAIN in mpg?
i'm looking forward to record my mpg after tuning in the EBL with its lean-cruise HiWay mode

 

Dunno but every car I did it to saw a small gain in mileage. I usually just make block off plates because something about recirculating exhaust into the intake don't sound good to me.

 

well, it redirects some amount of exhaust gas to the fresh intake charge to lower the fuel needed to make a combustible a/f mixture.
e.g. if the engine needs 200cfm at a certain rpm, load, etc. it will only take in 150cfm of fresh air and therefore need 25% less fuel to do the mixture, the other 50cfm are exhaust from the EGR and don't need to be enrichened. the ecm compensates for this mixture by adding spark advance (SA).
at least that's how i understand it seems strange that you saw milage gains with that removed, dunno.

 

Recirculating exhaust gas, also gives unburnt fuel a second chance to burn, resulting in less fuel wasted it in the atmosfere.
If ewerything is set up and tuned correctly, in reality, EGR improves mpg.

 

ultimate tbi mods
14.5 psi fuel pressure
matched injectors
injector pod spacer
egr delete
ngk plugs
msd wires
msd coil
180 thermostat
shorty hooker headers with custom ypipe
magnaflow catback
no emissions
open element with spector filter
no a/c
stage 2 tbi chip
i have been getting 17mpg in town and averaging 24 on the freeway. this is with a 3.23 rear.

 

I use to have a LO3,ive now upgraded to an LO5 350.Its still a throttle body though
I average about 15-18 MPG these days
Ive got an edelbrock open element air breather, Edelbrock TES headers,and a 3 inch y pipe. My heads have also been cleaned and polished.
I also have a custom chip made by CustomTBIChips.Great guy that works there. And last but not least,i have a fan setup to where it kicks on at 165 degrees

 

I'm not a big fan of putting money into an LO3 motor. I like to focus on weight, suspension/chassis, and drive train, that way if you want to do an engine swap later, your mods aren't wasted.

An Aluminum driveshaft (LS1), and aluminum drums, will give you a slight performance boost (rotational weight) and will simultaneously improve your MPG. A relatively cheap mod too. Also helps get rid of that annoying vibration at high speed.

 

Just put an aluminum driveline in last month and it deffinately helped with vibrations. looking for aluminum drums but i cant see to find any!

 

aluminum drums are very little gain. you could purchase them at advance auto parts, they're performance drums, but are double the price of cast iron.

I "think" i felt very little drag from rear when WOT, but its really not much, not worth it imo.

I only did it because I got a used set for $25 from another member.

 

With an LO3 I think you should take every little advantage you can get. Replacing your iron drums with the factory aluminum ones saves you 10lbs of rotational weight. Allegedly good for one tenth off your quarter mile time.

 

eh I doubt that. I keep an eye on at the junkyards for some but cant find them.