I've been researching what turbo size I want to run on my (to be) daily driver for a long time. Its a 1998 BMW 528i with a 2002 LM7 (80k miles) and a 1995 4L80e (~100k miles and in 'apparently' good shape).

I have VERY tight clearance near the firewall, and likely cannot fit a wastegate pipe drivers side, so I'm planning on copying APS and using Ford style T3 housings to run an external wastegate (frankly internal if it fits but I'm skeptical).

Essentially I'm trying to decide where to spend my money, an upgrade here means a cheaper option somewhere else, but reliability here is somewhat important. I'm considering 3 different primary turbo options (I'd add a garrett but they are $750 or more now most places and its not worth it to me):

Ebay T3/T04e hybrid - About $150 shipped (57 trim):
http://www.ebay.com/itm/170717412795?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT
Mitsubishi 20g - $540 plus shipping from forced performance:
http://store.forcedperformance.net/P...178-04600.html

Or a Borg Warner S200sx 7670 aero turbo $615:
http://www.ebay.com/itm/Borg-Warner-...Turbo-Charger-http://www.ebay.com/itm/Borg-Warner-177268-Airwerks-Turbo-Charger-S200SX-7670-/181336727603?pt=Motors_Car_Truck_Parts_Accessories&hash=item2a3882e033&vxp=mtr
Does anyone have experience with the chinese T3/T4 hybrid's - I've seen the bigger stuff is proven?

Is the extra $800 for the pair of Mitsubishi 20g's worthwhile? I get water cooling and real branding...is the newer aero worth it for the BW units? I'd have to buy turbine housings too so its even more $$.

I'm looking to make 475-550 whp max on 93, and maybe a bit more at the track (650whp max) on race gas. If this motor goes I'm getting an 05-06 4.8L... and good spool is important to me so the small turbos are attractive.

Experience is welcomed (I've had a 6262 on a 2.8L and want something a bit snappier if possible).

 

What size does the 20g measure out to ? The eBay 57/56s seem like a good option. Do you have room for a bigger t3 turbo

 

Internal gates carry their own physical installation problems.

ie they must be orientated a certain way, there is the actuator and linkage. It's often easier to use a bare turbine and external gate.

The external gate doesnt have to be close to the turbo.

Take a look on the Camaro 5 forum

AGP Turbo, IPS Turbo, Hellion and DKT all offer low mounted twin kits, with slight variations in implementation.
But all quite compact.

Only thing I'd say if trying to use them in another vehicle...the Camaro's must sit pretty damn high off the ground, as relative to the oil pan etc, the turbos do sit pretty low
The sellers offer a range of turbos, some with their own cast housings to make them more compact.

DKT

http://www.camaro5.com/forums/showthread.php?t=333684

AGP

http://www.camaro5.com/forums/showthread.php?t=374650

http://www.camaro5.com/forums/showthread.php?t=288657

IPS

http://www.camaro5.com/forums/showthread.php?t=306833


Or there is the likes of the APS kit, TTi etc for the Vette's and other vehicles which are also pretty tight fitting. Although these do place the turbos quite far forward which can be difficult with steering linkages etc

What sort of space do you have underneath ?

 

The 20g is 52.6/68 compressor with a TD05 turbine (49/56). The turbine is a little smaller than I'd like but it seems to work fine - these things are known for being a bit late to spool but being super reliable (OEM 80's tech so yeah theres that).

Yeah, the APS GTO kits are the closest replica I'll find, but I have an ultra low clearance moroso oil pan and it is level with my lowest point, with a stock LS1 intake I have 1/4" clearance to my hood.

I expect to run a wastegate pipe off the back of the turbo housing and tap into my downpipe about 16" downstream of the turbo with the wastegate. I am like 99% sure internal wastegates would be a pipedream but I can weld to the housing to get a wastegate pipe and a downpipe.

 

I managed...miraculously to squeeze a pair under my car, although the T56 and steel bellhousing did help. Your auto probably eats up room around that area.

The centre section almost straddles the bellhousing/block junction.

But I got a couple of biggish BW's under mine, but virtually no part of the setup sits lower than the oil pan itself ( Autokraft Camaro type pan )
One wastegate tucks tight beside the bellhousing, the other high up tight beside the T56

Amazingly I did it without cutting any metalwork on the car at all. I did have to switch to a remove oil filter setup though, and make custom oil/feed return for the bock. Which the Autokraft pan actually lended itself very well to.

 

Dead set on twins? A single GT45 or On3 will fit the bill for $350 or less.

 

I have 3 real issues:
1.) The E39 chassis has sheetmetal separating the brake booster/master area and the engine electronics area on each side of the rear of the engine bay, at about the frame rail width (so I can't get wider than them (28-30"range)

2.) The 4L80e didn't fit in my car as it was and required extensive use of a 4 lb hammer and losing foot room in the cabin. So, I have really limited space in front of the firewall and behind near the transmission.

3.) The steering column is really intrusive on the drivers side (stock is an I6 with exhaust to passenger side) so its super intrusive for a V8.

You asked before how much room I had below, its about 5", maybe 6" high by about 16" wide that I can stuff things on either side of the tranny. in front of that I have space to squeeze the turbo's pretty high up (might even gravity drain) but I don't want anything big in case I get a 4.8 - I want to have full boost by 3200 rpm's or so because I want to run a 3000-3200 RPM stall converter, assuming with a cam I'll need 15lbs or so street. That means all of these can make that with the right housings, anything bigger might not.

The AGP kit solution looks trick but I'm 95% confident I wouldn't be able to fit the extra pipe coming down, my turbo placement is higher in the car (because my car is shorter in height) and so the downpipe will have to drop about 1.5-2" to clear the floor pan

And I think my turbo's can sit with the DP flange about even with the back of my block.
Its really a matter of fitment. I was set on a nice EFR 9180 until I realized I didn't have any room. From the back of my grill after I add my oil cooler, inte-cooler, AC condenser, radiator, and fans, I have 1/2" gap to the belt drive.

A single is technically feasible in my car, its just so much of a compromise in plumbing compared to this its not funny - and I've seen decent reviews for the ebay stuff I linked that totals $300 shipped. With new flanges to get external wastegates and downpipe off the 5-bolt, and decent ebay wastegates it would be about $250 - so $550 total.

 

Also, I want to add, I appreciate your help, I've seen you post some seriously helpful things over the time I've been here.

I've been thinking about this for a long time and looked at almost every chassis and kit to find how to make it even work on the drivers side of my car, somehow I' missed the AGP kit, but really the APS is the one that showed me the solution. I'm fine with welding to cast (I have a shop that will weld anything for $60 an hour, and do a fantastic job, they weld titanium sheeting daily...) so as long as I can have a single scroll manifold I can make it work by drilling a hole a welding a pipe on for a wastegate, but I'd rather use a Ford style housing if I can.

 

The truck style manifolds weld really easily.

That was my biggest concern when I did it. But so far they're holding up great, and I just welded them myself !
I just cut and adapted them with some 2" ID Sch10 bends. Lots of people go for larger diameter, but from reading smaller would help spool, and so far I've little doubt when on higher boost I'm making over 4 figures with ease