Hello all!

I am looking for some sort of guidance as to what most people do re: turbo LS1s. Right now I have a '92 BMW 5 series with a custom built motor, 76mm turbo, direct port nitrous, and direct port methanol... but I am always looking to do more. Right now my car is geared toward being a street/drag car, and I'd like to keep it that way if I ever put a V8 in. The idea of swapping an LS1 has been in my head since I joined up on Yellow Bullet, and I realize I don't know enough about the engines to know what path to take or to forget it entirely.

Fabrication and building motors/cars is nothing new and I can fully pull it off, but I need guidance on the actual engines. I see iron and aluminum blocks out there - is there a pro or con (other than weight) of one over the other? I see 5.xL and 6.0L engines - pros cons? I've been looking around at used complete engines since I don't have an LS1 parts, but would I be better off considering an empty block and machining/building it up? I don't know what stock parts are or aren't good enough for what I want to do. If I did do this, it'd be a single turbo, preferably aluminum block (assuming there's no downside), probably a T6 GT4788, and mated to an automatic most likely - probably a TH400 if I can get it to fit in the BMW or a Tremec T56 if I decide to keep it a street car.

So basically - what do turbo guys build? What compression ratio? What pistons/rods/crank? Right now I use Wiseco pistons and Eagle rods and am happy with that combination, but I don't know whats what in LS world. So if some of the experts could chime in and give some pointers, I can start looking at it financially, and see if its something I'd like to continue. The BMW motors are expensive to build, so I am not sure it'd be that much more money and I already have a built BMW motor I could part with to offset this. We'll see - thanks for any input!

 

I realized I can post pics - maybe give you guys an idea what I've done





Maybe I can do an LS motor similarly???

I'll be reading!

 

Nice car. First off, you'll want to post up your question in the Hybrids section. It's where all the "Dr. Frankenstein" type guys hang out. Secondly, you'll want to think LS2 or 3. The LS1 is a really good motor, but the 2/3 are just that much better. They all will get into the 700-800 rwhp without too much short block mods, and unless you're going to go bizzurk, you wont need a iron block. Good luck with your build and, most of all, post pics when you do it!

 

I think thats the first time I've seen bias plys on a 5 series

How much power do you want is the real question.

That turbo is pretty capable and I'm sure your setup is already pretty capable so I am assuming your going to the ls1 in hopes to create monster numbers, if your not already.

Easist/cheapest way is to go with a 6.0L truck iron block which will prob handle 600whp or more (depending on how reliable you need it to be) on an absolutly stock engine, except some upgraded valve springs. Also can be had for a few hundred dollars for the complete engine.wiring harness, accessories. The 5.3 is similar and you can get them practically free.. but when the 6.0L is so cheap.. the 5.3L isnt really worth it anymore.

From there if you just change the pistons/rods and get ARP head studs... 1000whp is pretty easily obtainable and relativly cheap. This can be done but its even easier if you go with a stroker version from a company like texas speed, (their 408ci)

If you dont want the iron block in there the ls2 would be good the ls3 would be even better aluminum blocks but expect to pay at 2k or more for these engines used. Texas speed makes some stroker versions of these as well (the 402ci) these will both deff get the job done. Obviously more displacement makes it easier. Theres only about a 90lb difference between the iron and aluminum setups.

Looking at those pics.. the ls1 shouldnt be too much bigger than what your running right now, but the layout will be different, so you'll deff have to do all new hotside/coldside piping, chances are you'll be able to keep the turbo in the same or similar placement in the engine bay so you'll prob be able to keep your DP the same or only have to modify it slightly.

 

sick 5 series

 

Thanks everyone for your input - It may sound stupid but what cars do the LS2 and LS3 come in? Iron block V8 sounds heavy to me, but I am not sure! If I mustered up the will power to event start something like this, the goal would have to be 1200 or more horsepower. Do the blocks themselves handle this power decently? I don't want to get into epoxy filling blocks and such as this is still a street car. I would definitely do pistons and rods and perhaps an aftermarket billet crank if necessary. The pricing on some of the domestic parts seem super affordable, but I am not sure entirely. I hit up ebay and craigslist hoping to find some cheap bare blocks, but then I realize I don't have heads or accessories like I do the BMWs so that would be expensive in the long run.

Thanks again for the help perhaps I'll post in the hybrid section!

 

Jon that is sexy looking!

 

Thanks!

 

The iron block V8s arent that heavy because they come with aluminum heads and plastic/composite intake manifolds. I wouldent be suprised if they were only slightly heavier than the I6 you have in your car now, and I wouldent be surprised if the aluminum blocks are actually lighter than your I6 which I believe is an iron block with aluminum heads.

If you want 1200 or more whp I would say your biggest issue will be keeping the heads down, but with how cheap you can get these parts you can spend the money to oring the block and get block/heads machined for larger head studs. If you can keep the heads down you can do 1200whp with the 6.0 iron block with just pistons/rods, stock crank should be fine (no one really breaks factory Ls cranks) although again it would be easier with a stroker, a 408 iron block should be able to handle most anything you throw at it.

The problem with the Aluminum blocks at that power level is that they distort and that is partially why they push water. The ls3 block is prob strong enough though to push that power and not push water, but you may get away with an Ls2, especially again if you went with a stroker crank and got a little more displacement to work with.

Really the iron blocks arent as heavy as you'de think, but if you want an aluminum block your gonna spend more money. Just depends on what you want.

 

Thanks for the info! I am all for an iron block if its not a huge weight on the front axle It would definitely be the way to go as I really don't like sleeving if you can avoid it. As for the water, thats an issue BMW heads have being so long. Right now I machined my head out to use 1/2" ARP head studs vs the stock 10mm head bolts. I would o-ring the block and coolant/oil passage for sure. The LS heads are a lot shorter so in my mind I should be ok holding them down. I think 6.0L is more than enough to think about - right now I am on 2.9L and have barely driven the car the way it should be, but at 29 psi on a 76mm the thing was frightening (accidental overboost haha). This seems promising - so an iron LS1/LS2/LS3 is the way to go? How much would a long block tend to go for? Oh, and also, how are the factory heads in terms of flow? How expensive are a set of high flow heads - is it necessary? I love how affordable cams are for these engines - I can't get a set of DOHC BMW cams for < $1000!

 

bad *** bmw..i've seen you over on yellow bullet. i would stay with aluminum if u can..unless u went with the lsx block with is pretty heavy but can run 6 bolt heads and 25+psi.. 2 67mm will get you over 1000whp with 2 67mm turbos and a 370-408ci. looks like u'll need the space in there.

 

Pretty cool... My friend and I are doing his 5 series right now. pics in sig link.

 

Pwrtrip I saw your friends car over on bimmerforums or somewhere - sweet setup!

 

Jon K very nice setup you have there. how much power are you making? is it a 2.5 or 3.0 ltr??

Chris.