....

 

Well, first of all you need to keep in mind that even though you appear to have no shortfall in the cash department, you will be voiding the warranty on a failry expensive car just by running the leaded high octane fuel on the M3, let alone installing a high boost SC. Though speaking of cash, it astounds me that someone would think of financing a $75,000 car (E55 AMG), even with interest rates as low as they are. And speaking of $$$, super high octane race gas is currently running ~$8/gal, something to make even the wealthy think twice, IMHO. And you will probalby need to buy it in 55gal drums. This creates a storage problem, a convenience issue when it comes to fueling. And you will be limited to a range of 1/2 tank of gas (out and back).

Money matters and practicality aside, I think you would be in uncharted territory in a number of respects. First, there is the basic question you raise of will the motor stand up to 10psi with high octane and water injection. It might, and it might not and I doubt the answer will be readily available, though a BMW board would be a place to look. Still, take anything you read there (or here) with a grain of salt. There are a lot of "Internet Smokey Yunicks" out there who don't know a fuel pump from a windshield washer. My gut feeling is that it would not last long if you did anything other than cruise in it.

But the other major area is the ancillary systems to support the HP. Just bolting on the SC is one thing. Being sure there is enough fuel, that the rest of the drivetrain is up to the hp increase, and having a way to tune the car (hack into the factory ECU vs. an aftermarket system) can be major issues that must be addressed. And one other thing, your car will no longer run inclosed loop once the race gas contaminates the O2 sensors.

I am sure there are other issues I haven't mentioned. But overall I think the idea is a non-starter.

Rich

 

Ouch, Rich, you got me where it hurts. When using a w/s washer pump for water/alky injection I put gasoline in the jar. Big oops.

Listen to Rich, Mikael. His points are excellent. If this is practical, one of the BMW tuners probably has tried it, and if they haven't, there's probably good reasons not to do it.

BTW, if you REALLY want to go fast, Rich's ride should suffice. I hear his cats won't ride with him anymore.

 

Cats, dogs, wifes, none of them will ride with me. My 15yo daughter loves it though! And Jon, I know you know a windshield washer pump from a fuel pump. I'll be you even know a lug nut from a bolt!

But seriously, I may be biased by personal preference. But if you want to make really big hp by even high level modding (as opposed to applying OEM resources) I think you are best off starting with a LARGE displacement motor. Start with enough cubes, and you can make 500+hp all day on pump gas for surpringly little $$$. <$10,000 will buy you a 500+hp small block that will run with near OEM levels of reliability on pump gas. ~$15,000 gets you a pump gas big block with nearly 800hp ready to bolt in and go. For example: http://www.theengineshop.com/engine4.shtml

Rich

 

Wives? as in more than one? The plot thickens.

 

It's really not in the same class as the bmw but look into the evo 8 and the wrx sti. They both handle pretty well and have a huge aftermarket so they would be easy to mod. Actually why don't you look into the cadilac CTS-V. 400 hp ls6 from the z06. I think they go for about 55k.

 

It's not the power or the boost but rather the DETONATION and PREIGNITION that will kill stuff. There's always a max compression for any fuel since most engines have only so much capacity for increased VE and are trying to do all they can to trap the most VE they can in NA form. With really good heads and a good cam you will not be able to run as much compression as really bad heads and cam since the actual cylinder pressure will be higher.

Now with a blower it's even much higher VE than an NA engine plus usually it's already hotter even BEFORE compression so you usually have to run reduced compression with the same fuel. You can only have so much before you detonate and start taking out parts fast.

 

Seems to me that you could switch from running 93 pump to 104 unleaded and you would not mess up 02 sensors. And it would probably handle 10 psi. Maybe. You'd have to put on the kit and dyno(tune) it.

Does the 5psi kit run on 93 pump gas? If so, then 10 psi kit with race gas as out lined above could work under controlled circumstances.

Your foes will be your head studs and other engine parts. In the example of the EVO, they run like 15psi from the factory but when you turn them up folks will at some point upgrade the head studs because the head lifts. The factory head bolts stretch I guess.

It's also possible that the BMW factory pistons and rings are not super FI friendly, they might be tight gapped for superior NA performance but they might become problematic with your goals. I would check that out.

 

Why not just put a slightly thicker head gasket on and/or have somebody open up the compustion chambers to drop compression. It would probably be cheaper in the long run vs. having to fill up with 7-8 dollar a gallon fuel.

 

Have you thought of calling Dinan BMW? They tune and modify BMWs and can probably get as wild as you want. They would at least be able to answer your question, and might even have a package that would work for you. Maybe it's worth the call.