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Sorry Guys,I tried to edit my post from yesterday at the library and their system went down,so I am posting again.
I have a truck that I tow with and am re-doing it.5.3 LM7.Fuel pump is bad and tank is leaky.I am going to replace the entire fuel system from scratch,tank,pump,lines,everything.Pulling the engine,it runs good 110k miles,runs good,not replacing.Going to run E85 only,and going to plan and build a system for that only.
I don't beat on this truck by revving it up.I want to max out torque from idle to 4000 RPM.I should be able to run high compression on E85.
I am on a low budget,but those are the basics.I will be able to get tune and chassis dyno time from a friend.Not sure best way to get the big compression,heads or pistons? Don't need huge flow numbers,can't take advantage of it at lower RPMs.But would like to avoid having to completely break everything down to re-balance everything.
I am not looking to change engines or go with more cubic inches.Or spend tons of money,but I am firmly going with E85.Thanks!
get a set of 243 heads, mill them down to 61cc to maintain compression....as far as a cam for good torque, Id recommend a Cam Motion 206/210 115+5 .553 .553....you can use that cam with stock pushrods and some LS6 Valve Springs...
From gathering up of dyno results and power curves of various builds and stock engine power curves,it looks like what I am seeking is the same thing that the factory is seeking from a production engine....Highest Torque and a flat torque curve from idle to 5500 rpm.
So the factory intake,heads,valves,injectors and all the other components are fit together to do this.They would rather not see you wind things up over 5500,probably most drivers don't either.Maybe they will make a bit of an exception for the Corvette or Camaro or a few other purpose built High Performance models.
I do see an area that the factory has not really exploited for the typical,run of the mill factory engine.E85 and high compression.Because of the idea of "Flex Fuel",or the ability to run the engine on both gasoline and E85,they never have built an "All E85 Engine" to take advantage of E85.From what I can tell,they are leaving a ton of power on the table by not doing it.
How about a basically stock LM7 5.3 running 12:1 compression? 12:1 compression is going to require a piston change and cylinder head change.Because I don't care about a drop off of power above 5500 RPM,heads don't really need to be worked or ported. I am going to imagine that piston/combustion chamber design would be important.
Does anyone know of any data about E85 specific head design? I wonder if the larger injectors and fuel load change the desirable cylinder head design compared to gasoline.I can't seem to find any builds or data where a big increase in compression was the only variable changed (and injectors,of course),most builds change a ton of other things,so it is hard to make solid conclusions on what the power increases on these other E85 builds are coming from.E85 also lets you keep a ton of timing advance in the engine,and the fuel charge is much,much cooler.
I am thinking that a LM7 5.3, 12.5:1 compression engine,stock except for heads and pistons would make 450 ft lbs of torque from 1500 to 5500.
The idea behind a low revving engine is reliability, and the similar can be said for low compression. mixing low revs with high compression is like mixing racing fuel with a stock engine- doesn't quite make sense but eh.
I built my last car completely around reliability, no question. So, stock compression ratio (9's) was good from a 5.3 to run pump anything anywhere. Didn't want to risk $1000's in Head/head work nor risk the machining aspect of head/block work, this adds to reliability as well. But what about power? Who cares how reliable it is, a Civic is reliable, if it doesn't also make ur passenger **** their pants. That is why forced induction is necessary.
The idea behind a low revving engine is reliability, and the similar can be said for low compression. mixing low revs with high compression is like mixing racing fuel with a stock engine- doesn't quite make sense but eh.
I built my last car completely around reliability, no question. So, stock compression ratio (9's) was good from a 5.3 to run pump anything anywhere. Didn't want to risk $1000's in Head/head work nor risk the machining aspect of head/block work, this adds to reliability as well. But what about power? Who cares how reliable it is, a Civic is reliable, if it doesn't also make ur passenger **** their pants. That is why forced induction is necessary.
I agree with most you say.
The factory has to consider reliability to be the most important factor,nothing else is a close 2nd.Most people here would also want that (admit it or not).
Not sure if 12:1 or a little more would be called unreliable.I think the LS7 Corvette engine is 12:1.So the factory is trusting it and trusting people to put the right gas in it.I don't know if they are seeing a lot of service or failures with it.I would have to believe the Gen 3 or 4 engines are not so inferior that they can't be trusted with that compression.
A supercharger would certainly be a good way to get the low end torque.Not sure if the supercharger is the most reliable way,though.ZLA SC is the only production supercharger for it,hard to say if it is reliable as daily driver equipment.How many years did GM go without putting a supercharger in a production vehicle,then they come up with the ZLA,and look what happens.Maybe it is all ironed out now.
I can see why the factory does not want to tailor an engine to E85.They have to trust people to put the correct fuel in.Then they have to trust that the E85 is E85.That would be my burden,and to not cry about it.But 105 octane opens up a lot of good things.
Didn't even get into camshaft yet,will get to that when it gets there.I'll find a camshaft maker who can custom grind and is willing to talk about it for 15 minutes or so.I'm sure there is an off the shelf grind that would cover most of what they would consider an ideal valve event for this setup.
Finding the right used heads is going to be key.I can't see it needing much head work to be decent at the lower RPMs than most people shoot for.They will need milling to be true,flat and to pickup the compression ratio.Not sure if running E85,with the larger injectors and fuel charge changes what is best.I'm sure huge flow numbers wouldn't matter for much.
The factory has to consider reliability to be the most important factor,nothing else is a close 2nd.Most people here would also want that (admit it or not).
Not sure if 12:1 or a little more would be called unreliable.I think the LS7 Corvette engine is 12:1.So the factory is trusting it and trusting people to put the right gas in it.I don't know if they are seeing a lot of service or failures with it.I would have to believe the Gen 3 or 4 engines are not so inferior that they can't be trusted with that compression.
A supercharger would certainly be a good way to get the low end torque.Not sure if the supercharger is the most reliable way,though.ZLA SC is the only production supercharger for it,hard to say if it is reliable as daily driver equipment.How many years did GM go without putting a supercharger in a production vehicle,then they come up with the ZLA,and look what happens.Maybe it is all ironed out now.
Oh no, sorry. Supercharger is terrible because of it's parasite. I mean, its good if you can't find the fab/time. But a Turbocharger was the only thing on my mind when I said Forced induction.
Also I think 12:1 stuff is DI. I don't know the production settings but just be careful trying to compare 2014 technology to 2004 tech.
I can see why the factory does not want to tailor an engine to E85.They have to trust people to put the correct fuel in.Then they have to trust that the E85 is E85.That would be my burden,and to not cry about it.But 105 octane opens up a lot of good things.
Flexfuel sensors can tell any % of ethanol content in fuel, including the 10% from 93. There are varying opinions about this and mine is the sheer volume of ethanol required at 750 horsepower (newest production vette) would be ridiculous to plump into every factory vette. Then they would need to keep it from year to year- you can't suddenly drop E85 compatibility from 2018 to 2019. I mean, it doesn't seem like that would do something like that anyways. So imagine in 2019 when they had 850 horsepower or whatever, what kind of reliable OEM pump is going to be in that bad #@*!, they already ran out of DI juice and are using DI + Direct port in factory cars because its just so much power to feed through a small line at such a high pressure for supposedly 70k or 120000~ miles
Good point about the direct injection and compression.I would only be guessing if I thought it allowed them to bump compression up a point from the older injection setup.
You give some good reasons on Why they don't do a dedicated E85 engine.Fact is,the only good thing that E85 has going for it is the 104 octane rating and the ability to handle a lot of compression or boost without detonation.If they made a decision to build an E85 dedicated engine,I am sure it would be quite a bit different in physical ways,not just by the electronics/computer that allow it to fire up and run.I am sure they could back the timing off for bad or wrong fuel the same way they can now,but do they design in any performance gains for E85 mode vs. gasoline now?
They may not go all in on E85,because face it,it makes no sense as a general automotive fuel,and if the gov't pulled the plug on the programs and subsidies,bye-bye cheap E85.
Remember,this is a truck engine,for a truck that tows frequently.It needs power straight off idle.A twin screw does that.The LSA uses about 7.5 HP on average throught my desired RPM range.
Well, ethanol is easy to make. Easier than gasoline. We have unlimited source of 99.98% ethanol at home in your own distillery. I consider it a racing fuel, I mean compared to gasoline it sure is. It just takes around 35% more of it, making it less attractive to daily drivers, long distance drives. Thats why they make flex fuel cars and trucks, you just put whatever is available or some ETOH to clean it out. Ethanol is unlikely to burn into carbon fragments, so it doesn't generate the black sooty mess gasoline is capable of. Overall, an ideal fuel, but it takes far more patience to deal with it. Aeromotive found in testing that one needs to clean their fuel filter every 10 run hours when using E85. Sealing of the fuel tank from ambient moisture is essential. It is more picky about its container and needs a close attention to filtration and you have a successfully implemented racing fuel. high power means high fuel flow and so rapid filtration of a large volume of fuel can be a challenge I guess.
OP I know you said you didn't want to go more cubic inches or another engine but realistically that's you best option for a low dollar build. You can sell the 5.3 to offset the cost of the 6.0 and have it rebuilt for less than the cost of the LSA supercharger and components needed to make it work. A 6.0 with 9.5-1 or 10-1 compression would keep you in the pump gas range, If you decide to stick with E-85 a bump in compression even in a low rpm engine will still be more thermally efficient and make more torque.
What kind of budget do you have for the engine side of the build alone?
highest azeotrope of ethanol is 98 or 99% I forget but its very high. More than 96%. You just need higher tech equipment to get there but it goes.
In any case even 50% will do pretty dang good.
Also, a turbo can provide fairly responsive torque at low rpm, it just needs proper size everything. Think of all the factory 2.0 and 3.0L Turbo/twin turbo engines of history, Skyline RB, Supra 2JZ, Evo and Silvia, they all have great response and mid-range. Factory 3L 2jz-gte engine twins can do 440rwhp iirc, the first smallest turbo upgrade starts out around 500 and maintains all of that response because 60lb/min is a tiny turbo these days. The 2jz is cheating though, It is superior to a V8 in almost every way except displacement. Hemispherical combustion chambers, top down plug access, only 1 side of exhaust manifolds to plumb and they are no where near the spark plugs, large aftermarket variety of reliable low cost single turbo manifolds, factory piston oil squirters, reinforced main girdle (the block weighs as much as an IRON V8), factory solid lash valvetrain capable of 8,000rpm out of the box, reliable variable cam timing control method, what more can I say... But DAMN Shes only 3L and seven times the cost of a JY 5.3... F that
highest azeotrope of ethanol is 98 or 99% I forget but its very high. More than 96%. You just need higher tech equipment to get there but it goes.
Nope 96% is it, You have dry it, azeotropic mixture boils at a lower temperature so it’s impossible to use simple distillation to get above 96% without using different method. If you can do it through distillation I have a friend who would more than happy to pay you for your secrete process. He makes a few hundred gallons a month in his barn.
Yes a turbo be great and most likely cheaper than an LSA supercharger if he can fab some of it himself.
okay, I will concede that maybe you wouldn't call it distillation after 96%. Ya finally won one. Don't get used to it XD
And as usual wiki has something throw in there, maybe this is a method
" The bottom product of the low pressure column primarily consists of water, while the bottom stream of the high pressure column is nearly pure ethanol at concentrations of 99% or higher. " https://en.wikipedia.org/wiki/Azeotropic_distillation
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OP I know you said you didn't want to go more cubic inches or another engine but realistically that's you best option for a low dollar build. You can sell the 5.3 to offset the cost of the 6.0 and have it rebuilt for less than the cost of the LSA supercharger and components needed to make it work. A 6.0 with 9.5-1 or 10-1 compression would keep you in the pump gas range, If you decide to stick with E-85 a bump in compression even in a low rpm engine will still be more thermally efficient and make more torque.
What kind of budget do you have for the engine side of the build alone?
Yes,I am considering all the options...the easiest would be 6.0 or even 8.1.install and move on,and keep the tank full.
I bought the LSA SC a few years back,got the lid and IC from GM right after,just looked at the old invoices for everything,about $900 total,so not a ton into that.Have to do the typical coupler/bushing update,none of that was sorted out at the time.
Maybe there is some new data and methods out there for super-low RPM boost with turbo? I just didn't think I could make 5lbs with it at 2000 rpm,no matter what I could fabricate for it.
But,with all this wonderful new info,maybe I can boost an 8.1 and just make the fuel in my basement?
I bought the LSA SC a few years back,got the lid and IC from GM right after,just looked at the old invoices for everything,about $900 total,so not a ton into that.Have to do the typical coupler/bushing update,none of that was sorted out at the time.
Well hell that changes everything lol , If you already have the supercharger it's a no brainer. If there's one thing I like about my truck is that with the LSA supercharger it has tons of torque. I can put my truck into 5th gear at about 30mph and leave it there and not downshift on hills at lower speeds. It just keeps a steady speed. I don't tow with it I'm sure it would rip up the road at 65mph too.
If the motor runs good then I wouldn't do anything but add adapters to mount the supercharger to those heads. Get the fuel system setup for e85 and tune it. If you run a conservative tune the stock engine will work just fine.
Last edited by LLLosingit; 04-10-2018 at 09:27 AM.
Here are my engines that are supercharged. First one is in my 2000 S10, It's a stock 13,000 mile LY6 6.0 with LS9 cam and LSA supercharger.
This engine is a stock 5.3 with around 200,000 miles that has a 6-71 roots blower on it running a flex fuel setup. It's just a test mule/play toy that's likely going into my son in-laws 73 Nova.
This picture is from before I bought the engine from the previous owner. It had problems on a dyno pull and the previous owner wasn't seeing the power he wanted so he decided to go to a big block rather than keep going with it.
It made over 900hp before being fully sorted out and torque was over 700ftlbs at 3,000 rpm. It's going into my 1951 Chevy 5 window truck project.
04-05-2018, 06:09 AM
Homeless Guy Cheap TorqueMonster 5.3 
