bmw 325 turbo question

[The_uprising]

hey guys i nkow that this isn't a dsm question, but i've been a diehard fan of 'em for my whole life and you guys are the only people i knew that could help me out here. i own a 95' bmw 325is that has 190 horsepower and has a 1/4 mile time of 15.9 sec. it has a 2.5 liter inline six cylinder dohc engine. i has almost no torque and only gets power at around 3k rpm. It redlines at 7k. shortly i'll be adding racing cams, a custom cai, and a custom exhaust, not to mention the racing chip. this all will come to about 210 horspower, making it equal to a gsx. anyways, i feel that my car is way too slow and i have some knowladge of turbos from reading on this site. I hope to get a garret ball bearing gt30 turbo and hook it up with a custom exhaust manifold and a skyline r34 intercooler. i've heard that these turbos are effective from 250-400 hp, but i'm not positive on those numbers. anyways, i was hoping to get some input on what you thought would be a good turbo. the only thing i'm not sure about is if this turbo would take too long to spool up since i have a six cylinder as opposed to a four. so, any input would be great, thanks a lot

 

[nine5raptor]

From what I've heard through the grapevine, bmw ecu's hate modifications (don't know if this applies to as far back as 95s), but assuming you don't have to fight the ecu all the way along, I think a turbo is a great upgrade for any car (I may be a little biased here ) Based on stock output, your engine will spool a turbo quicker than a 2.0l dsm engine. The higher compression and larger displacement help tremendously in this area. The best thing to do would be to search the net for turbo beemers with similar engines. I don't imagine it will be a very cheap project, but it would make a badass car.

To simplify things a bit, you may also look into a self-contained (oiling wise), intercooled, centrifugal supercharger. It is essentially a belt-driven turbo minus the whole exhaust side. The guys at www.procharger.com could probably get you setup to make 300+ horse on pump gas.

 

[The_uprising]

thanks a bunch for the reply, for a while i didn't think anybody would. As far as looking at other turbo'd bimmers, most of them go with a garret gt25 package put together by some brainless company trying to suck people's money from them. they use spearco intercoolers and some offbrand bov with their own custom exhaust manifold. the ecu's are pretty ###, but there are many companies that sell customized chips to get the full power out of the mods that you are running. I've looked into getting the gt25, but it's only good for up to 300 hp from what i've read and i plan to get some 350-400hp when i'm done. as far as superchargers, they are cheaper, but i've wanted the rush of turbo boost ever since i've started driving. that and the fact that i want to be able to control the boost levels and be able to have more control over it. as far as the price goes, i'd only be paying for the trubo itself and intercooler core since i'm taking up welding and hope to creat my own piping and manifold. thanks a lot for the reply though.

 

[Zidane]

Hey you are in luck. The 95's have the good ECU. It is very friendly towards modifications. Get something bigger than a GT30, in fact you should get in contact with ATPturbo.com or better yet go to the 'Forced Induction' section of Bimmerforums.com and have a look around. Lot's of info there about everything you might want to do. Good luck

 

[The_uprising]

hey thanks a lot man, i've already looked there though. just a bunch of rich europeans that buy premade turbo kits. but if i get larger than gt30, won't it take a long time to spool up? also, i'm afraid if i get too large a turbo than i'll have to run higher boost. i've heard that my engine can only take 5-7 psi of boost naturally. although i do plan on getting a headgasket spacer so i can run higher boost, chromemolly rods, and titanium valve springs and retainers. i'm not sure if that would help with boost. the last thisng that i want to do is blow up my overpriced engine.

 

[2gGSX]

You will definately not take a long time to spool up; as stated above you have more displacement and a higher CR than DSMs. The GT30 is actually a pretty good choice for a street turbo for that car.
As for your second fear, with a larger turbo you'll actually run lower boost to make the same power as a smaller turbo w/ higher boost (it's all about how much CFM or lbs/min the turbo pushes, not PSI).
I don't know much about your engine, but definately read more on bimmerforums about boost modifications, and see how much other people are running. There are definately things you can do to strengthen your engine for boost, which would probably be rods, pistons (maybe), and possibly new sleeves if they're really weak (once again I know nothing about BMWs, I'm just saying thats an option).

Good luck though, 2.5L turbo + RWD would = fun

 

[The_uprising]

wow, that was incredibly helpful, you guys can't imagine how much i appreciate your help. i expected to get heat on getting a bmw instead of a dsm and then for wanting to turbo it. damn, i love dsm'ers. every single one

 

[Zidane]

One more thing brutha, your rods and pistons are more than beefy enough to handle a good amount of boost, after all BMW and the germans generally know how to make a bulletproof bottom end. You can even keep your pistons if you go with a thick headgasket. So once again, good luck

 

[Defiant]

Yeah, they all got here before I got home.

But no torque from a straight-six?

whew.

 

[ITSME4G63]

Yeah, they all got here before I got home.

But no torque from a straight-six?

whew.

ALways a smart ass remark

 

[prostreetdsmx1]

i worked on a buddy of mines 95 M3 that had a td06 20g turbo on it and all i can say is that turbocharging it was a NIGHTMARE. no shop was able to make it work correctly and the tuning was a disaster. i have another friend who has a 325 and he is running a vortech blower on it that seems to work quite well. his whole family is from germany and his father has 30 years of BMW building and racing experience and he said that a blower is the only way to go on a BMW motor. his car now makes about 320whp and it is a dream to drive, the power band is very linear and it handles like a dream.

the motor stock makes a very good feeling amount of torque. i know from driving it on the back roads that the cars can get out of turns very quickly.

anyway best of luck with the build up.

 

[Turbonium]

maybe look on the supra forums?? as there motor is more like yours as far as picking a turbo, thye have bigger motors but less compression so mayeb thye could give you a good idea? they seem to be real helpful over there at www.supraforums.com but i'm only on the MK2 part where there isn't much turboing going on. g-luck
Ryan