Lower compression

Originally Posted by MarcusLSB

What do you plan on running for an ECU (have you got that far yet in planning?). If E85 is relatively available to you I personally would run the stock 10.5:1 compression ratio and tune the car to the lowest blend of ethanol you typically see in your area. Maybe thats 70%? Ethanol is a VERY capable fuel, and even on probably 40% ethanol you'd have no problem making 400-450rwhp on a turbo'd M52. You'd want to likely redo your fuel system from front to back, including uprated pumps to support the additional flow needed for E85. Some would say you're fine using existing lines and just installing an uprated pump.. which is probably true as well but that depends on your budget.

To OP: Exactly what Marcus says. Note the point I forgot to mention. Pump gas figures suffer a bit on a high compression build, but E85 will yield you untold bounty in so many ways.

Note also Larry from SP's post about how even stock compression on OEM BMW turbos is now 10.5.

At this point you should see some fairly compelling evidence for doing a high compression build. If you can commit to E85 in the manner that Marcus suggests (safe), you will have one of the better (best?) 330's around.

An optional but quite nice electronic item is a gauge that will simply read out your current ethanol content of what ever is in your tank. It is always good to know for sure.
http://www.gtfabrications.com/product.php?productid=850
Shop around for best pricing. An expensive, but handy option.

Also: "re do fuel system front to back" likely means needing larger injectors when switching to E-85 and FI.

You can start a "build" thread when you decide on a direction.

Good luck!

So how bigger would i need to go in injector size and what pump and filter. Would my vf kit injectors be enough. Sorry for my ignorance.

Originally Posted by Edgar3498

So how bigger would i need to go in injector size and what pump and filter. Would my vf kit injectors be enough. Sorry for my ignorance.

That would depend on turbo size (assuming turbo) amount of boost predicted and estimated RWHP.

I found Areomotive tech department very helpful in calculating flow of E85 needed (in pounds per hour) for builds with known turbo size, known boost and and estimated RWHP. Their calculations help determine fuel pump requirements and injector flow requirements.

A rough (as in not exact) rule of thumb is that for the same RWHP that you would get using gas or race fuel, you must enlarge everything by 33% to flow the amount of E85 needed. This has to do with BTU's and efficiency.

This would be a good time to start doing some serious RESEARCH (as in SEARCH, GOOGLE etc) on the subject of using E85 for forced induction (primarily turbo) applications.

The benefits are numerous...cooler, less soot and deposits, cheap per gallon costs, faster spool time. Race gas type power available ALL the time at pump gas prices!

E-85 does not come out drawbacks too..harder to store, water absorbing qualities, larger flow hardware needed, and so on. Time to do some heavy reading I am afraid. There is tons of information on this forum, other forums and the web.

Some guys (in Canada) like E85 so much that they will drive 12 hours in a rented truck just to purchase and transport drums (months supply) of E-85 in the closest areas of availability. Some of us (CA and FL) are lucky to have E85 readily available and close by. Good Luck.

Thanks dave Im researching like a mad man. It would be convinient to find someone who is running e85 on a e46 so that i could see and talk about his modifications an experiance with this

Originally Posted by Edgar3498

Thanks dave Im researching like a mad man. It would be convinient to find someone who is running e85 on a e46 so that i could see and talk about his modifications an experiance with this

I think Jacob (from St. Paul, MN) is running E85 on a turbo'd M52. He posts here on occasion.

Originally Posted by Edgar3498

Thanks dave Im researching like a mad man. It would be convinient to find someone who is running e85 on a e46 so that i could see and talk about his modifications an experiance with this

VERY smart direction to take your research! Looks like Marcus may have given you a great lead. Good luck. Stay in touch, please.

So I'm running Bosch green top injectors 42lb i think thats 440 cc
Im thinking of going up to 600cc to make the same hp that im making now in my head it makes no sense. My goal is 420 rwhp more or less so i will be going 1000cc is this reasonable

Originally Posted by Edgar3498

So I'm running Bosch green top injectors 42lb i think thats 440 cc
Im thinking of going up to 600cc to make the same hp that im making now in my head it makes no sense. My goal is 420 rwhp more or less so i will be going 1000cc is this reasonable

Here you go :
http://www.gtsparkplugs.com/InjectorSizeCalc.html

E85 will give you more power so just saying that 30% plus to make the same power is incorrect

Thanks this helps alot

Originally Posted by Bdave

The main technical issue with FI and compression is that as you increase boost, fuel/air temperatures increases _during_ the compression stroke. If those temperatures raise too much, the fuel/air mixture will undergo combustion prematurely. Under WOT and full boost, these unwanted occurrences, called detonations, can damage an engine very seriously.

There are several ways to reduce or manage conditions that lead to detonation. Lowering compression is the more drastic of such methods. What is best for you want to do depends on what you want to do and how much money you have to reach those goals.

The most obvious solution is to use a fuel that has a higher octane rating (detonation resistance) such race fuels like 110 octane race/aviation fuels, C16 or E85. Some problems are cost and general availability of the fuel but it's probably the easiest path to running higher boost.

Water or methanol injection can help lower pre-combustion temperatures and/or raise octane levels as well but require significant design consideration of the delivery system. It's best to install these types of options with a kit because the exact application needs to be tuned. With a kit you don't need to start from scratch. I view it as a band-aid approach the problem but it's a nice next step for people who want to fiddle with those types of setups.

E85 is more convenient because it's less expensive than race fuel and more available but it requires that parts of the fuel system be upgraded, rubber components might need attention since some components made of lower quality materials will degrade and fail. E85, as a fuel, has a lower power density than gasoline; so you will need to inject more fuel to burn an equivalent amount of air.

Regardless of the exact fuel, if your motor is consuming more air, it will require more fuel, so you probably will be looking at injector and fuel pump upgrades depending on your goals and the capacities of the components your car has.

The most drastic method is obviously an engine rebuild for lower compression. That's done either by replacing the pistons with a model that has more dish, using a thicker gasket or even removing material from the head.

Overall, boost can be considered to be another form of compression. Between the boost and cylinder compression, and a few other factors relating to intake air temp etc, there exists a compression limit where temperature increases will cause fuel to burn spontaneously. That limit relates to the octane levels of the fuel you are using.

I hope that answers your question.

Did not read the rest of the thread to see but this is information worth quoting

Originally Posted by wtbass21

Did not read the rest of the thread to see but this is information worth quoting

One of my better ones, I agree. Thank you.

I just want to emphasize that the experts like Sound Performace say the best bet for FI is a high compression build run on E85. Whether or not the build needs new rods or forged pistons is up to the builder, taking into consideration max boost and HP, and generally accepted limits of the OEM components.

So in theory what would be my limit with my 330ci

Originally Posted by Edgar3498

So I'm running Bosch green top injectors 42lb i think thats 440 cc
Im thinking of going up to 600cc to make the same hp that im making now in my head it makes no sense. My goal is 420 rwhp more or less so i will be going 1000cc is this reasonable

Regarding injectors, I think it's worth noting that not all injectors are created equal.

Here is a thread of HPF testing their ID2000

http://www.e46fanatics.com/forum/sho...d.php?t=882897

It's worth noting two things.

1. There is more to injectors than just their flow rating, atomization of fuel help with better combustion. With more atomization, it's easier for the fuel to phase change to a gaseous state during the compression cycle. That's obviously interesting because that phase change cools the mix.

2. As boost increases, you should also increase fuel pressure since the effective pressure is actually the difference in boost to fuel pressure. If you run 70PSI fuel pressure and 20 PSI of boost, the fuel pressure is 50PSI relative to the intake pressure.

While you may not want injectors this large, you certainly want something like this but scaled down. At around minute 13:00 of the video John starts to compares a couple of other injectors including the OEM S54 BMW part. At minute 15 he shows a 1k cc generic injector.

Maybe something like this? http://www.injectordynamics.com/ID1000.html

Does anyone know if these ID1000 will have idle issues on a 3 liter I6?

Is about 800 hps on gasoline and perhaps 600 on E85 a good estimate?

What pump should i use ????

Originally Posted by Edgar3498

What pump should i use ????

Many favor the Bosch 044/040 pumps, however they are a bit more expensive then most pumps but they're incredibly reliable and consistent.

JP over at Radium Engineering wrote a great blog post comparing most of the more popular pumps on the market right now.

http://radiumauto.com/blog-page.php?...l-Pump-Test-73