V8 fuel economy

[Frank Lee]

When I got 33 mpg I was on the highway between Pinellas County and Orlando going about 80 mph.

For the record I did get 33 mpg with a max speed of 80 mph. Some of the trip was at 45 mph on SR92.

I detect some irregularities here... Why am I reminded of George Wiseman (still on sabbatical)?

I've milled and port-matched the head on the 'Coupe but can't make any claims as to how much that helped fe, if at all. Blueprinting is nice but it doesn't do miracles especially at the low rpm end of the spectrum.

[ksa8907]

I wish you luck. You're going to have to address aero if you plan on 50mpg at a steady speed. I don't want you to be discouraged, but I think 35 is more realistic. To put it in perspective, my cts will do about 33-35mpg @ 55mph. 3.6 v6 turning about 1550rpm.

You should look up some of the work done by "pgfpro" on his first gen eagle talon.

[pgfpro]

Thought I would join this thread.

On my Talon, I also am trying to get great fuel mileage at 65 to 70 mph. I have hit a road block due to my stock gearing and aero (28.8 fps piston @ 70mph and a .29 Cd). I'll be lucky to get 40 mpg at 65 mph. My best so far is 38 mpg @ 65 mph and that was throwing everything at it including the kitchen sink.

My mods.

Engine:
2.0L
modified 1g turbo pistons, spray-guided crown.
modified head, spray-guided high heat direct port.
custom camshafts.
intake manifold, high heat direct port w/adjustable port angle injection.

Turbo System:
High-pressure Modified Blow-Down Turbine 13g internal gate dump to atm.
Low- pressure stock configuration FP Red BB, mid mount.
DNP Turbo exhaust manifold.
44mm Tial Bi-Pass waste gate.
FMIC 3" core.
LP Turbo pre-intercooler.
Tilton 40-527 external oil pump.
Jegs 12V Vacuum pump.

ECU:
ECM Link Engine Management system.

EGR:
HOT/COLD Electronic controlled cold EGR system.

Transmission:
Transtar/IPT 5 disk front clutch kit in stock basket, Transtar/IPT end clutches, double up stock flexplate, John Deere HyGard fluid, Foreign Muscle DSM (Transmission Control Unit), EPROM Upgrade full line pressure with pre-set rpm shift points.
2g lock-up converter.

Right now I'm working on getting the largest tire that will fit in my wheel wells. So far I have fitted a 1.5" larger tire then stock. The only way I will get close to my new goal 40mpg @ 65 mph is to reduce rpm. Piston speed is a killer when comes to fuel mileage.

Anyway I like that you are trying to have the best of both worlds (racing/fuel mileage) and hope for the best for you. Good Luck!!!

My Talon build thread.
http://ecomodder.com/forum/showthrea...awd-28776.html

[user removed]

I was going to refer him to your thread pgfpro. Thanks for bringing your experience.

regards
mech

[Occasionally6]

50 (US) mpg sounds very ambitious but there's no harm in trying.

It might be possible, subject to valve lift conflicts with that required for 800HP, to add in AFM from a later LS. The ability to switch to a 2.4l engine would reduce some of the pumping loss at low engine power requirement.

Likewise, it may be possible to use the variable cam timing from a later version of this engine.

Without having to respect emission requirements lean burn will help. You could also implement EGR. They won't be additive but could be complementary.

BMW had an engine series a few decades ago - ETA - that were optimised for fuel efficiency. Designed for low rpm operation with light valve spring pressures etc. Might find some ideas there.

A compression ratio optimised for E85 will help but there are diminishing returns. Once you get past about 10:1 the thermal efficiency gains really start to level out with further increase. Past 13:1 it's pretty flat. That you are using pressure charging will tend to push the CR in the wrong direction and probably less than 10:1. How effectively can you intercool it?

[cRiPpLe_rOoStEr]

You may even be able to get it to 800hp, but while doing an eco-drive you won't be able to use all that power. I guess you have already seen some motorcycles have different injection and ignition mappings that can be selected thru push-buttons, and you could try something similar in your Camaro. Either EFI Live or those aftermarket programmable ECMs such as FuelTech may give you the ability to get such control.

Originally Posted by greasess

I know that aero mods like a boat tail and things like eoc would really help me achieve 50 mpg but I want to do it without any of that. I would really like to hear what cripple rooster thinks of this.

The 4th-gen Camaro already looks kinda aerodynamic, and I like its design and would also rather not mess with it. In regard to EOC, I'm actually not unfavorable to it.

[greasess]

As for the valve lift requirements for 800hp, my stock cam is about .450 lift and my intake ports were tested to flow 272 CFM at that lift. That was without a valve job or flow form around the intake port. That should be plenty of flow to reach my goal. I know the DOD version of the 4.8 would help meet my goal but that won't work with my LS1B ECU. I would have to use an E67 or some other ecu. I use EFI Live and am familiar with tuning the LS1B only. I would also have to make up a custom harness to use a DOD compatible ecu. I can also command fuel in the "cruise" areas of the VE table to be as lean as I want while still running 11 to 1 AFR under boost so I can use the same map for the strip and eco driving. Also, I know that 11/1 CR isn't typically a good idea for boost but I have seen some people run 15 psi on a stock ls2 with 11/1, a 4 inch bore instead of my 3.77 bore, less quench area than I have, more chamber hotspots and so on. I haven't done it yet. I'm just saying that it's not impossible on 93. pgfpro, what cr are you running on your 4g63? Those are great results. If all else fails I'll ceramic coat my pistons, chambers and valve faces. That's supposed to get gains of up to 15% on economy for some engines. Thanks for all the reply. Keep the ideas and criticism coming.

[cRiPpLe_rOoStEr]

Originally Posted by greasess

If all else fails I'll ceramic coat my pistons, chambers and valve faces. That's supposed to get gains of up to 15% on economy for some engines.

I've recently been lurking about ceramic coating, but it's still not so widely available in my country.

[greasess]

This is the company I will go with if I do get any ceramic coating done. I saw a few of my customers make power gains with these coatings and nothing else done.

[pgfpro]

pgfpro, what cr are you running on your 4g63?

The engine that's in the car now is at 8.0:1 This is a modified stock 1g piston on a deck block and milled head. I'm using this piston because I wanted to test running in lean burn around 30:1 A/F at medium load 0" Hg to 2psi at freeway speed.

For the racing part I use these stock cast 1g pistons becasue I'm trying to run a high 9 second pass on pump fuel. I did some testing last year and while pushing the envolpe I broke a few pistons when the engine detonated.
When these pistons break they just crack the ring land and drop down in compression, and so far I haven't hurt the bore and or head. I then can drive the car home and change out the piston without pulling the engine in less then 8 hours and be ready to race the next day. i have 8 pistons ready to install at all times.

I have also another 11.5:1 engine I will be testing later this Summer. This is my E85 engine with a built bottom end.