E46Fanatics - View Single Post - Misconceptions about FI on an M54..
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Old 05-31-2009, 12:30 PM   #118
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Join Date: Nov 2004
Location: DeLand Florida
Posts: 2,910
My Ride: 1998 528i
Originally Posted by ritos530i View Post
Ok, first off, how long the oil lines are have nothing to do with anything. The pressure in BMW oil systems is so high it makes no difference. Besides with turbos you need very little oil to keep them cooled.
I understand that the exhaust gases may not be as hot as it would be when exiting the head as appose to in the rear of the car. Still doesn't justify how much energy you need to make a turbo spool which this has more to do with the turbine wheel than anything else and a real rear mounted turbo are configured for this exact purpose. You can't take just any turbo and stick it in the back and think it's going to give you the same results. I could have had my turbo configured to spool just like any front mounted system. I have this high powerful nitrous system and don't see the point with the early spool.
As for the size, Sorry but you are wrong again, I have the smallest turbo that STS makes and it's rated at over 600+bhp which is not a small turbo at all. Small turbos are 300-450rwhp max.
I've seen actually comparisons between setups on the Z's.

My point was this, STS runs a smaller exhaust turbine to keep the spool RPM's down some. This means that at high CFM (read high load high RPM) the exhaust housing is a larger restriction, read less efficient. They then run a decently large intake housing so that they can make more power.

This results however, in the turbo being less efficient at higher power levels, than a turbo with a larger exhaust housing (which if placed at the manifold would spool about the same).

As for oil lines - long oil lines just mean more potential areas for leaks, more oil in the system, and more work to get it set up. It works fine, but its something to consider.

You get that heat point out from the engine bay, which is huge, but in turn, you pull fresh air from a low point on the car, so driving in the rain can be more dangerous.

Like I said, I'm not anti rear mount, I'm impressed by how they are doing on the Z's, and if there was a better tuning option than reflash (long story on why I say this) for my car I'd be a bit psyched about putting one in myself. The tuning becomes cost prohibitive quickly though.

1998 528i 5-speed Work in progress
1988 Toyota Pickup (4WD 5-speed) daily
2007 San Marino Blue 350z 6-speed sold
1996 328i 5-speed sold

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