E85 V8 Engine Efficiency Projects

[Aguila1]

Hello! My current interest lies in improving power, efficiency and emissions in traditional American V8 engines. I understand that this is at the opposite end of the ecomodding spectrum, but is relevant nevertheless for two reasons.

First, the traditional V8 powered vehicle, hotrod or muscle car is not going away anytime soon, as long as gasoline remains relatively affordable. While many performance car enthusiasts do not concern themselves with fuel economy, an engine can be made to be more fuel efficient and still produce high power levels, as factory late model V8s have proven.

Secondly, if it's true that it takes as much energy to build a new car as the fuel consumed in its entire service life, then it makes economic and ecological sense to maintain, conserve and use older cars, albeit in an improved, more efficient state of tune.

My first project, a Pontiac 455, nears completion. I only reused the block and crank, replacing everything else in the interest of improving volumetric efficiency and increasing power and durability. I am documenting this build-up in an educational video series on machine work and engine building on Vimeo. I can't post a link, yet, but if you go to Vimeo and write "Pontiac 455" in the search you'll access my work. (I'm the guy behind the camera).

We've already bench tested the engine and next we'll take it to be engine dynoed and tuned. The 700r4 transmission is also being rebuilt and the subject of another video.

I've been using E85 fuel in this vehicle for the previous two years and curiously my fuel economy did not suffer as expected. Tuning with a wide band A/F meter set at lambda showed a cruise reading of 1.18-1.24, so the leaner burn might have helped. With only 9.25:1 compression, it was not optimized for E85. So we raised it to 13:1 for increased volumetric efficiency and replaced the aluminum intake with an original cast iron manifold to keep temperatures high and help vaporize the E85 fuel.

Our next project involves a SBF, namely a World Products Man O'War 427. We will also be shooting for improved fuel efficiency over ultimate power production, so the 455 dyno tests may decide which direction to go as far as compression, heads, cam, etc.

We're also building a stock 4.3 Chevrolet LT engine to squeeze better mileage out of a seventies Impala and another Pontiac project - a turbo 301 engine to explore its ultimate potential.

Eventually, I'd like to see all this knowledge and experience with E85 and fuel efficiency be applied to an aero car project with a tiny turbocharged engine. In any event, I hope you find this line of experimentation interesting and applicable to some of your own projects. Thanks for having me aboard!

[Daox]

Welcome to the site. Sounds like some interesting projects.

I think E85 has some great potential IF an engine is designed to run on it. This flex fuel engine stuff really gives it a black eye.

I'm curious why you only went to 13:1 CR? Not that I have much experience, but I've heard you can run much higher.

I don't agree that it takes as much energy to make a new car as the fuel it uses during its life. Even the highly critisized Prius (high energy to make, low fuel use) uses way more energy to run than is used to produce the vehicle. Of course my only info here comes from Toyota so... In any case, I still love to see old cars running around. I've had a few of my own over the years, currently working on a '51 F-1 pickup.

[oil pan 4]

The eagle/tallon DSM guys and some of the WRX guys do a lot of stuff with small turbo charged engines and E85.

I thought an aluminum intake would help vaporize the fuel. You know how the aluminum moves heat faster and all. Just don't use one of those "air gap intake manifolds", unless you are running a switchable WAI/CAI rig (that would be kind of cool).

Hot rod magazine has done a few E85 builds over the years, you could search some of their articles.

[oil pan 4]

Originally Posted by Daox

I'm curious why you only went to 13:1 CR? Not that I have much experience, but I've heard you can run much higher.

I was wondering that too.
Was 13:1 the best you could do with out custom pistons or other machine work?

[Aguila1]

If it was pure ethanol, perhaps 16:1 or more, but I'd rather be conservative and sneak up on the compression, based on experience, than regret going too high. I decided 13:1 was high enough to show a difference. Remember, this also is with cast iron heads, which are less detonation resistant than aluminum. Another factor to consider is dynamic vs. static compression. On the contrary, the cam might have lowered the dynamic to the point that efficiency will suffer and maybe I could have gotten away with a higher CR. The dyno session and subsequent testing will give us hard data...

[cRiPpLe_rOoStEr]

I know, I know, folks know me as a dieselhead, but one of the few good things one can enjoy as a Brazilian-born is the experience with ethanol

One thing to consider about the intake manifold is that it can freeze when the ethanol is sprayed from the carburettor into the manifold. In Brazil some dedicated-ethanol cars had coolant flow passing thru the manifold to heat it, preventing it from frozing under that circumstance, just like a cab heater core. If you can't get a heated manifold, insulate the one you're going to use. Making a shorter way from the carburettor to the chambers is also a good way to overcome that freezing. When Volkswagen released its air-cooled dedicated-ethanol engines, the ones with dual-carburettor were more successful for that reason, since the carburettors sit lower than in a single-carburettor setup. No wonder when Chevy released its first fuel-injected dedicated-ethanol car in Brazil it featured MPFI even though the gasser still relied on a TBI unit...

Originally Posted by Aguila1

If it was pure ethanol, perhaps 16:1 or more, but I'd rather be conservative and sneak up on the compression, based on experience, than regret going too high. I decided 13:1 was high enough to show a difference.

With 16:1 compression, you wouldn't even need spark plugs
Lots of farm trucks and agricultural machinery in Brazilian sugarcane plantations run on ethanol instead of the regular Diesel fuel they were supposed to use. In older engines only some oil is added, while newer ones with electronic controls require an ECM reflashing. The highest compression I saw some folks using in spark-ignited liquid-cooled naturally-aspirated engines with Brazilian ethanol (E96h - 96% ethanol with 4% water) was 14:1.

Another factor to consider is dynamic vs. static compression. On the contrary, the cam might have lowered the dynamic to the point that efficiency will suffer and maybe I could have gotten away with a higher CR.

Slap a supercharger on it and play with a longer intake valves opening. Miller cycle FTW

[Aguila1]

Muito obrigado! I did have some drivability issues when the temperatures dropped to near freezing - with 2.73 gears and overdrive, it would buck at low rpm. I suspected freezing, but never actually saw any icing. Keeping the engine and intake hot is the reason I went back with the excellent Pontiac cast iron manifold.

We might throw a supercharger on the engine in the future, as the bottom end has been greatly strengthened, but more than likely a better candidate is the "Ford", which is of a magnitude stronger with all forged internals and NASCAR derived block.

I enjoy the insight into the Brazilian ethanol experience, which has led the world towards a more renewable and sustainable future.

[cRiPpLe_rOoStEr]

Originally Posted by Aguila1

I did have some drivability issues when the temperatures dropped to near freezing - with 2.73 gears and overdrive, it would buck at low rpm. I suspected freezing, but never actually saw any icing. Keeping the engine and intake hot is the reason I went back with the excellent Pontiac cast iron manifold.

Getting the idle stability right after the start-up is still the biggest challenge while running on ethanol, and it will rattle a little more when it's still not warm enought. No wonder many Brazilian cars, either dedicated-ethanol or flexfuel, have an auxiliary tank which holds a small amount of gasoline to the start-ups at temperatures usually below 50F when automatically-controlled, altough older vehicles had the cold-start activated manually at any temperature. But nowadays some vehicles such as the Peugeot 308 with a 1.6L flexfuel engine have pre-heaters at the injector tips, not requiring the auxiliary gasoline tank.

We might throw a supercharger on the engine in the future, as the bottom end has been greatly strengthened, but more than likely a better candidate is the "Ford", which is of a magnitude stronger with all forged internals and NASCAR derived block.

When using the supercharger, a cam with a longer intake valves opening is good because it will emulate a longer power stroke and a shorter compression stroke, altough the supercharger will overcome the power and torque losses from the discompression generated by the longer intake valves opening.

I enjoy the insight into the Brazilian ethanol experience, which has led the world towards a more renewable and sustainable future.

Well, the Brazilian ethanol experience was not so great because the usage of compression-ignited engines was too much neglected during the ProAlcool era. Sure the prevalence of the indirect injection in light-duty Diesels at that time, and the requirement for some lube to be blended into the ethanol to avoid damages to the injection pump, made it harder, altough nowadays with the prevalence of the direct injection in Diesel engines the ethanol is easier to adapt to their current emissions-control requirements, actually even easier than biodiesel.

[cRiPpLe_rOoStEr]

So, any update on this project?

[Aguila1]

Excuse the tardiness in reporting back. In the interim I have been struggling with unexpected detonation issues, both at light throttle and at WOT, preventing the engine from realizing its full potential. The time that has passed represents trying to correct different things that might exacerbate detonation with little or no success.

1) Carburetion: Removed my modified Q-Jet. Changed to an E85-specific modified Holley 800 Spreadbore from E85racingcarbs.com. because of detonation and power "falling down".

2) Fuel delivery: Added in-tank E85 Walbro fuel pump, using a Tanks Inc. fuel tank. Changed all fuel hose to Aeroquip -8 AN lines inlet and return. This assured a constant supply of fuel to the carb, around 6 lbs. I suspected fuel leaning out and causing power to fall down, as well as detonation.

3) Torque convertor and transmission repair: O'Reilly Auto Parts sold me a defective radiator that leaked water into the transmission. I suspected transmission slipping as a contributing cause to detonation. Incidentally, O'Reilly's never made good to reimburse me and stopped returning my calls. Still detonation.

4) Ignition: Upgraded ignition to locked-out MSD distributor with MSD 6AL-2 programmable to use a laptop to change the shape of the timing curve. No matter what curve was tested, nothing helped. Radically cutting back timing, killed power and still detonated.

5) Engine temperature: Removed excellent factory cast iron intake for aluminum Edelbrock Performer to cool intake temperatures. I also changed the thermostat to cool the engine down. Temperature gauge read lower, still spark knocking at WOT.

6) Carburetion: Now doubting the efficacy of the Holley Spreadbore, purchased brand new Quick Fuel Q-Series E85 carburetor. Seems to be more responsive and powerful, but still detonates at WOT.

My conclusion: Total fail. The compression is simply too high for the octane available in E85 using vintage iron 1969 Pontiac D-port heads, which by design, have poor anti-detonation qualities. I used an Innovate Motorsports wide-band O2 sensor gauge for tuning and was able to have excellent drivability, but no matter how rich I ran it, it still knocked, verified aurally and visually with a knock light. The compression calculated out to 13.13:1, dynamic compression with the Crower 60919 cam 11.92:1.

While other racers are running 14:1 and higher, they are most likely using modern heads with a fast-burn combustion chamber design and perhaps more radical cams to reduce dynamic compression. The result was totally unexpected given the extensive research I had done on E85 and ended up costing me a lot of money and time and aggravation, but sometimes that happens when you push the limits on the road less travelled. Call it a learning experience.

As I write this, the old heads are off. I am waiting for a brand new set of CNC-ported KRE D-ports, aluminum with a modern combustion chamber design, port-matched to an Edelbrock RPM intake. The compression ratio with 74 cc heads will be 11.75:1, conservative for E85, but allowing me to run outside my E85 availability range on 93 octane if necessary.

One last bit of advice: Make sure you dyno-test a new engine before tuning in-car. No one wanted to run this motor because they weren't the ones that built it. If I had dyno-tested it from day-one as planned, much of this could have been avoided.

Sorry, again, for not following up sooner, but it's been a long aggravating and disappointing journey, that at least taught me some important lessons, which stand as a warning to others.