318is question... - BMW Forum

shopkeep · 06-09-2006, 04:22 PM

1. Thinking of getting a turbocharger for my 318is (friend selling a stock turbo off a Nissan for cheap, so why the hell not?)

2. My car runs great and is hella fun to drive, it has 175k miles....However, I was told by a friend of a friend that is a tuner that he thinks i wont get any more than 15-30k more miles out of my car before it just dies on me from the engine not being able to handle it unless I were to rebuild it because I just have too many miles on it.

3. So what should I believe?

saltshaker185 · 06-09-2006, 04:26 PM

well does the tuner work with bmws and realize that they are incredible cars even at high mileage??? if you get a turbo tuned right, it will live just as long as NA so yeah i would gopher it... just make sure u do it right...

ldsbeaker · 06-09-2006, 04:26 PM

Your car will last as long as you want it to.
Preventative Maintenance (not waiting until something breaks) is your friend, and will keep your car (and you) happy.
With that many miles on the clock, it might be useful to do a leakdown/compression check to see what kind of condition your engine is in now before trying to force more performance out of it. If you need a rebuild, now is a good time to do it, while it's still running. Know what I mean?

shopkeep · 06-09-2006, 04:35 PM

No the tuner doesn't work with BMWs, I figured he didn't realize how long they last and how generally well they are kept up by past owners, but I just wasn't sure so I wanted to ask around. Thanks for the advice.

He was also giving me shit that my car only has 138hp, can't wait till i give him a ride in it, his mind should change.

Ivan · 06-09-2006, 09:07 PM

its not as easy as strapping a turbo on. youre gonna have to do other mods including maybe a custom made exhaust manifold

shopkeep · 06-09-2006, 09:52 PM

yeap, putting in a turbo seemed like way too much work and money when i first considered it, but since I may get one cheap it just might make the work and extra money to do it worth it.

mrfc3s · 06-10-2006, 12:57 AM

this might be a stupid question, but why turbo it? these are high compression engines anyway, IMO keep it NA... if you want more power, upgrade your engine and internals(which is a pain but better than replacing vital parts more often...) As light as these cars can be... a 200-250 should be more than anyone really needs...
If you have an eta, swap for the "I" engne and build it before it goes in... if you still feel the same way, then turbo it...
Turbos couldnt possably beat Oldschool Mechanical Tunning could it? besides a correctly built motor will be able to handle more tunning than an old tired one...

just my .02, good luck anyways

DIRTE30 · 06-11-2006, 05:29 PM

Actually,
you will never get the same kind of $ to HP ratio out of N/A tuning! Just because it's a "high compression" engine doesn't mean you can't build a reliable turbo setup for it. The turbo essetially does all the things that the mods you would do to TUNE normally except it does it much more efficiently. As a N/A motor needs the most oxygen at wide open throttle but has the least amount of vaccume at that point to pull it in you eventually run into a "wall" as far as performance goes, at least without going crazy with compression and cams to the point that it's not streetable. Whereas with a turbo at wide open throttle when your needing Oxygen the most, you get it and not only do you get it, you get it compressed! That means that for a given volume of "air" you get (say your running 8psi) 8 times the oxygen into each cylinder. Essentially doubling the effective displacement of your engine! Assuming you tune your fuel and timing curve correctly and match your exhausts back pressure, you can double your stock horsepower without causing any extra wear on your motor. However, having built and destroyed many a turbo project, I would say that putting more than 7psi or so on a motor with that kind of mileage will most likely bring it to an early grave. Most of the time the problem stems from wear on the rings. Once a motor has that kind of mileage it usually has more blow by from the rings. You go adding a whole lot more pressure and fuel into that cylinder and you get a bunch of fuel into the oil in no time. This spells early death for your bearings! So have fun with it but don't get boost happy!

Good luck!

Starmavin · 06-11-2006, 10:35 PM

Quote:

Originally Posted by mrfc3s

Turbos couldnt possably beat Oldschool Mechanical Tunning could it?

The days of "No replacement for displacement" mentality are gone (or going). The days of building large displacement high compression motors to build power are fading away. And for good reasion, the main causes are emmesions, and the cost of gas. You cannot build a large displacement motor and have it be clean, take the 80's smog motors, engines from the 70's that belted out 300hp putt out half the hp from efforts to make them run cleaner. Larger motors gobble up gas at an alarming rate, for an example a 70's chevy 454 downs 1/3 a gallon of gas from start up idleing till warm in winter weather.

The plain truth is large, high compression motors are tempermental and unreliable at best, and can not compete with output of a well tuned forced inducted motor half its size. I have proven this with the 2.0L turbo 4G63 mitsubishi motor I just built, it blasted out 413hp to the wheels! With larger injectors and a reflashed chip, it has potential for upwards of 450! You'll be hard pressed to make that kind of hp with a naturally-aspirated motor twice it's size even with race gas.

JoeMadoo · 06-11-2006, 11:21 PM

You can send that motor over to me, I'll PM you my address

Starmavin · 06-12-2006, 05:19 PM

Send me 3800 dollars and I'll build you one, complete with turbo.