LS swap prep questions

[elmer91]

Hey guys, new to the forum, just picked up a 89 325i. It has higher miles (odometer stopped at 232k), and once the motor goes out on this thing im gonna do a LS swap into it. In the meantime i am going to go ahead and start gather parts for it. Gonna go ahead and apologize if I have to ask about some e30 specific terminology. Never owned an e30, or even a car for that matter. Always been a truck and jeep guy.

To start, my e30 is lowered, and im just not one for the lowered look, and it j wont work with my parents driveway, as i scrape pretty bad going up it. I want to go ahead and get some new springs for it and have it sitting as close to stock ride height as possible. Since the LS is so much heavier than the current 2.5, did any of you upgrade springs and other suspension stuff, and to what? If I do need to get stiffer/stronger front springs, would it be a good idea to go ahead and run those before the swap? I wouldnt care if it made it sit up higher, if that would be the only real problem with it.

I have also started to look around for motor and transmission. I was looking, into the LM7 since they are cheap and easy to find. Or would it be worth searching for a L33, since it has the aluminum block? Not sure what the exact weight difference is. I have read that the T56 is a popular tranny to put into it. Anyone run the T5 with any luck? If I find a T5 from an F-body camaro does the shifter line up with the stock hole still? And i know it wont be nearly as much fun, but what about an auto tranny, anyone done it and liked it?

One last question: tires. any need for a stiffer load rated tire? Going to order tires this week, and need to know since these tires will still be on when i do the swap. Also, any tire recommendations are welcome.

Thanks for any help!

[bmk]

I have an iron block in my cabby and with stock suspension and it still looks like a 4x4.
Iron vs Aluminum block really up to you, the aluminum is cost you a good amount more where the iron block is gonna weight a decent amount more 80ish lbs.
Yes T5 should work I know vorshlag used one in there LS swap http://www.vorshlag.com/forums/showthread.php?t=8131

A auto tranny wont work without significant modification of the tranny tunnel as they are much more bulky

[elmer91]

Sweet, thanks. Probably gonna order the H&R OE spring kit next week then. The weight wont matter to me, this is just gonna be for a daily driver, not really gonna take it to the track, so the iron block is gonna be the way i go. The T5 should also be cheaper than the T56, just not sure how easy it is gonna be to find.

[The Dark Side of Will]

Vorshlag used a 4th Gen F-body T5 and blew up several.

Unless you can find a T5 from a TPI 3rd Gen F-body (and those are fairly expensive), or from the Mustang 302, you want to stay away from T5's... they just can't take the heat.

The NV3500 would be a stronger choice, but it's a truck transmission.

[elmer91]

I wouldnt mind running a NV3500 as long as it would fit. Might search around for a T5, or hope i catch a T56 cheap one day on CL. Gonna do some searching on the physical size of different trannys to get an idea what would fit and what wont.

One more question i thought of: I want to go ahead and get a LSD for it. Will a stock one out of a s model (or any other BMW that has an LSD) hold up to the extra power or would i be better off getting an aftermarket one?

[The Dark Side of Will]

The 188mm diff is strong enough for most uses (drag racing with up to ~500 HP) but the 86mm CV's are the weak point. Either aftermarket axles (e.g. Driveshaft Shop) or 94mm CV's from an E28 or E34 will last.

[elmer91]

awesome, thanks for the info!

[Madhatter]

Unless you get the T5 rebuilt, they are generally only good for around 300-350ft/lbs of torque maximum. Start leaning on them, especially with mileage, and they do break. That's kind of right on the limit of just a standard LS1. Put a cam in it and go maf less, you'll be over that figure by a good 100ft/lbs. Can see why they break.

If you just go with a T56 right from the go, you'll never have to worry about breakages. Have to remember the E30 is lighter than the cars they were originally run in too, so the drivetrain doesn't see quite as much shock/loading. The rebuilt T56 i've got for mine is basically magnum spec, handle 600+ft/lbs of torque in a 3800+ lbs car. Even with everything loaded into it when finished, E30 should still come out a good 700lbs lighter (more if stripped for race use), so effectively the trans will handle more than I could ever contemplate throwing at it. Even with a 7L.

[shiboujin]

I'm waiting for my T56 to shatter.

[Madhatter]

Pretty cheap to rebuild it to magnum specs if you have enough torque to really worry it. If I break mine I'm going to have to look at a hollinger or something.