GuitsBoy

iTrader: (4)

My uncle swears up and down that the thing actually works, no matter how much time I spend explaining why its BS. He's a very knowledgable guy too, and probably the best driver I know. Ill hold off on purchasing my own though...

MrDude_1

iTrader: (4)

it does. read what i said for the simple WHY....

you could also take a flat piece of sheetmetal, drill a 1" hole in it, and run it between your lid and your throttlebody.... sure, you wont ever get the same pull at WOT.... but watch your MPG go up!

GuitsBoy

iTrader: (4)

I meant the increased power at WOT claim... The intake restriction makes sense as for MPG.

UofMN

iTrader: (1)

What is this lean cruise you speak of???? Is this only an ls1 thing or also ls2.

Thanks
UofMn

383ss

iTrader: (14)

it allows the a/f to run whatever you tell it to after a set amount of time 'cruising' you can set the mph on and off speeds also. typically you can run it at around 16.8:1 for a 10% or so increase in gas mileage.

it is illegal to run in the US because it increases emmisions. the aussies have it from the factory on some cars. you have to edit the code your pcm to allow it to run the routines.

GuitsBoy

iTrader: (4)

How are people doing this? Hex editor or such and then uploading the full bin to the car?

hammertime

iTrader: (1)

Considering that the switch to the 6.0L truck cam in 01+ LS1 engines was to improve torque, lets look at what was changed:

98-00 _____ 198/209 @ .050" 119.5 lobe separation
01-04 _____ 196/207 @ .050" 116.0 lobe separation

a narrower lobe separation generally should increase low end torque, and the increase in overlap (minor at this duration) may help to dilute the intake charge and lower EGT's

I would look at comp's XR259HR for a fair increase in low end power. I would not recommend 6.0L heads, as compression is power. If you are not concerned with max power, and only mileage, machining the stock heads for smaller chambers would build more cylinder pressure (think restrictor plate motor's - you are looking for gains with the throttle open 5-20%) and therefore more power. I think you'll have a tricky tune on your hands though, as you may run into serious detonation issues should you want to run it WOT.

Anything that lets more air in and out has to help efficiency. CAI, headers, high-flow cats and cat back are not really cheap items, but can help (what about electric cut-outs for the highway? Did you have headers from the 408 previously?)

Do post results, as we're all curious. I don't think 30mpg can be that hard to do, but your .57 6th gear does give up about 200 rpm @ 80 to a lighter F-body with .50 6th.

Good Luck!

slowpoke96z28

iTrader: (2)

like has been said before, don't change heads fo a bigger combustion chamber. yeah its more octane tolerant, but it will also lower mean effective pressure in the chamber, which means less torque per mass of air injested by the engine. so it would take a higher mass flow rate(and more fuel along with it) to maintain your cruising speed of 80mph. diesels get better fuel mileage, right? do they have higher or lower compression ratios? i know there are other variables when comparing diesel and gas, but its standardly accepted that a higher compression ratio, all else remaining the same, will net higher fuel mileage. and longtube headers will net a big difference in fuel mileage. every car i have had longtubes on has seen an increase in fuel mileage.

mr2guru

iTrader: (16)

Good points!

P Mack

iTrader: (6)

I would look at trying to get 87 to work with the stock compression. Higher compression is more efficient as a thermodynamic rule. With 10:1 versus 9:1, you're letting the burned gases push on the piston till they expand to 10 times their volume, then they get kicked out the exhaust port. The more you let the gases expand before pushing them out the exhaust port, the more energy you squeeze out of it.

It's possible that by switching to .040 head gaskets you could gain compression and be able to run 87 more safely because of the tighter quench.

Also try experimenting with your idle timing. I was able to cut my idle airflow significantly by upping the idle timing. It may not make a huge difference but it would be worth a try, especially if most of your driving is not highway cruising. https://ls1tech.com/forums/pcm-diagnostics-tuning/395359-idle-spark-advance-vs-idle-airflow.html

Also you may want to mess with your dfco settings so your pcm shuts off the fuel injectors sooner when you're engine braking.

allngn_c5

iTrader: (3)

I get over 34 mpg in 6th gear at 80 mph with the cruise set. That's actual, not what is on the readout. Readout shows 38 to 41 mpg on the highway. I use the fill it up, drive and re fill it up method and a calculator. LOL

Rubadubdub

Moron? Well if you knew anything then maybe the ******* obvious wouldn't escape you. The government is mandating the increased mixing of ethanol in gasoline. The addition of ethanol to gasoline leads to a decrease in mileage but an increase in the price of gasoline. Now go follow the yellow corn road in Kansas and stick a corn cob in your corn hole. We clear now Dorothy?

ringram

Yeah go for max compression and tread the line with compression and octane.
Good info here http://www.popularhotrodding.com/tec...power_squeeze/

Get a 160* stat and cool it down.

As Guits mentioned, go open loop and lean up your low map points. Even to 16:1 real low.

Use DFCO, make it come on immediately on throttle close. Dont drive faster than 50mph if you can help it. Ive logged thousands of miles with efilive injector duty MPG calculations and 50 is where best economy is at. Use 6th around 1500rpm.

Make your your tune is spot on and timing is good.

Use light/friction reducing oils. Drive with all the windows up and dont use the Aircond!

Go on a diet, dont take passengers, stay at home etc..

slowpoke96z28

iTrader: (2)

i think he meant the government, not you.

97LT1

iTrader: (3)

Yeah i have to agree that the ethanol thing really sux. It is raising gas about 10-15 cents in the city. Go out of town and take note of the price drop.


On the other hand taking a stock sports car installing shitty parts for better gas mileage is a really retarded thought. I say just do a budget rebuild on the honda, and save the miles on this car. You could do all of this while driving to work in your GTO for the moment.

SNW Vette

Hi,

Lower drag
Extend the front spoiler down to he ground. GM says this is worth ~2 MPG on a Vette
Lower the car
Optimize the body rake
Optimize the rear spoiler (non may not be best)
Tape up the grill like a NASCAR racer
Tape up the brake ducts
Tape up the body gaps like a Bonneville racer
Remove the right side mirror or get smaller mirrors
Remove the windshield wiper(s)
Add full wheel covers (Moon discs)

Lower parasitic loses
Remove the AC belt
Set the wheel alignment for near-zero camber and toe
Run 210F engine oil temp
Don’t over fill the engine oil or run it low & check it
Don’t over fill the trans or diff
Check that the brakes don’t drag

Lower friction
REM polish the diff gears
Microblue process the wheel bearings to lower the friction
Don’t over pack the bearings

Tuneup
Check that the throttle position for power enrichment is higher than your acceleration requirements

Driving technique
Draft trucks & SUV’s
Let the car slow down going uphill and speedup downhill
Coast downhill
Slow down in the rain (added friction lowers optimum speed)
Skip-shift (1-3-5-6 works on my Vettes)
Read about the old Mobil economy run

Engine mods
Optimize the cam to get the greatest vacuum at cruise rpm
Run a pan-vac setup and lower the ring drag
Mod the crank to lower windage
Lower the oil pressure
Lower the valve spring pressures

Philosophy
Do mods that you know will help even though the increments are too small to measure individually
Do everything you can

Best of luck,
Steve

Rokko

iTrader: (2)

No mention or debate about the truck manifold yet? Isn't it built for low rpm torque and power? I don't know if it'll even bolt up. Sorry if it doesn't and that fact is common knowledge,

Just throwing a thought out there.

sgt0704

iTrader: (3)

if you were looking at getting a new car, a cheap bike would suffice.

mr2guru

iTrader: (16)

Bikes are fun, I just got rid of my R1 last year. But for daily commutes it's too much of a mitigated risk to put out there on a daily basis.

Bikes are risks that are much greater than cars, something that I am comfortable with putting myself in for maybe 6hrs a week, not not 20+ in heavy unattentive traffic.

halfprice5

Water injection might allow you to run 87 and the 10:1. Since you seem accomplished at retuning the PCM it might work.