LS vs Turbo

[goodtimes]

I've been lurking and searching for a while, but just joined. I am thinking about building a street car that would be used as a DD when not snowing, and while I would try to avoid rain, it will inevitably see rainy days as well, that I can also use for a few track days per year.

I would like your input, in regards to how to approach the best overall set-up for an E36 M3 that would meet the aforementioned criteria. I have been looking at the two turbo kits (TT and TRM), as well as the Vorshlag LS swap kits. My concern with the turbo kits, is how well a high mileage, stock M3 motor would take to boost, especially when road racing. The LS swap kit offered from Vorshlag seems to be one of the most complete, however it still does not cover everything needed to complete the swap, and as a result I'm concerned with the time it will take to have a running LS car, as well as the reliability/maintenance of a swapped car.

I would especially love to hear from owners of each respective set-up, those who have owned both, or those who have experience with both set-ups.

[Volf]

These motors take very well to boost at any mileage. Depending on power all you'll need to do is get a different head gasket and not worry about the internals.

[khaos]

High mileage motors are the best: all the inherent stresses are worked out already. Counter intuitive I know read somewhere that formula 1 cars use 100k+ blocks for that reason.

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[bmwaddicted49]

thats interesting khaos!
so maybe a high mileage engine with rebuilt internals would be best? im looking into getting my engine ready for FI..

[KnudsonsM3]

LSx swap

[Tongboy]

go read the turbo forum about the guys fighting head gasket issues and boost creep and then read the ls swap about the guys trying to make stuff.

make a decision on what problems you want to have to address and go that direction.

obviously it's clear which direction I went. I'd challenge anyone with a turbo and roughly the same amount of cash I have into my car to run in just about any situation to show the LS beats up the turbos in basically every way dollar for dollar.

[khaos]

"... BMW started out using unmodified although lightened production blocks. The company's engineers discovered that high mileage blocks performed best, the ageing reducing th stresses within the metal"
Source: The Turbo Years by Alan Henry.

[pbonsalb]

Forced induction on a stock motor risks the headgasket. This is more of a risk as the miles go up. The stage 2 turbo kits come with a thicker HG and ARP studs to drop compression, so you are replacing the headgasket. That reduces the risk.

My view is that the mileage does matter. I don't care whether professional racers use "seasoned" blocks because they are "building" motors into those blocks, not finding tired stock street motors and using them "as is" because they have seasoned blocks. If I had a 100k mile S52, I would go ahead and turbo it, but be prepared for eventual failure if I pushed it too far. For that reason, I would not push it too far. Something like a Stage II Techniques Turbo system is well proven and plenty powerful just the way it comes. Stop there to minimize risk, but accept risk.

If the mileage is much over 100k, I would be counting on trouble. If you want to accept the greater risk, go ahead.

Building a motor ruins the budget and makes the LSx swap look good. For that reason, if I had a high mileage S52, I would factor in a build or rebuild cost when comparing the total LSx conversion cost versus the S52 turbo cost. The LSx would probably win.

I like my turbo E36 M3. However, mine is a Stage III running bigger everything and more boost, at greater cost, and at greater risk on a stock motor (but I have a rebuilt performance motor although it uses stock rods). I have over 500 rwhp and over 500 lbs rwtq on pump gas. No boost creep, no headgasket issues. Do it right, and you don't have any issues. Push things too far, do it wrong, and you probably will because you are asking a 250 hp motor to make 500 hp. The margins are reduced. It is not laggy at all but obviously does not have the 1000-3000 rpm torque of an LSx. Makes a great daily driver.

For road racing, I'd probably lean towards the LSx motor since it would be less stressed, unless you were willing to fully build the S52 turbo (meaning much greater costs).

[GG Allin]

LSx swap

+ twin turbos.

[Volf]

Do it right, and you don't have any issues.


^ That



Also what were your power goals? If low end torque and power is what you want a used twin screw is in the picture as well, and will make just as much power.


After lots and lots and lots of reading I think the twin screw might be the best Daily driver boost system you can get. You still get to play around in boost at low RPMs and make really good power.

Centris you have to rev the piss out of to go fast, and while turbo power comes on much earlier and stays on, it still lacks the low end grunt.

[pbonsalb]

The twinscrews as they have been installed are reasonable compromises between good peak power and good low end power, but are not monsters.

The dyno below shows 360 rwhp and 303 lbs rwtq for a Eurosport twinscrew. It does have great torque from 2000 to 3000 rpm. I can't tell when all the boost has arrived and what the power is like below 2000 rpm.

http://www.eurosporthighperformance.com/pdfs/TS_3.2L_vs_stock.pdf

Look at the dyno for a Techniques Tuning Stage 2 turbo and you will see that by 3000 rpm, the turbo has caught up to the twinscrew. From there, it runs away from the twinscrew, peaking at about 400 rwhp and 380 lbs rwtq:

http://www.techniquetuning.com/e36m3obd2turbo.html

[Tongboy]

The twinscrews as they have been installed are reasonable compromises between good peak power and good low end power, but are not monsters.

The dyno below shows 360 rwhp and 303 lbs rwtq for a Eurosport twinscrew. It does have great torque from 2000 to 3000 rpm. I can't tell when all the boost has arrived and what the power is like below 2000 rpm.

http://www.eurosporthighperformance.com/pdfs/TS_3.2L_vs_stock.pdf

Look at the dyno for a Techniques Tuning Stage 2 turbo and you will see that by 3000 rpm, the turbo has caught up to the twinscrew. From there, it runs away from the twinscrew, peaking at about 400 rwhp and 380 lbs rwtq:

http://www.techniquetuning.com/e36m3obd2turbo.html

only 9 grand! what a bargain

I kid, I know why supers are expensive, they are also obviously the simplest install of all the options by far.

realistic swap & ongoing costs are always interesting to me, turbos have a HUGE range from almost nothing upfront cost to 10k+ depending on how much safety you want to build in. ls swaps range from medium to high - after the basic parts its all about how many ponies you want to strap in. supers have a huge upfront cost, even used and have a very real horsepower ceiling before becoming not worth it.

[Moron95M3]

simple answer. YES.




(that means a boosted LS...)


I'm doing an LS swap soon in my 944...cant beat the power/available upgrades for the cost.

[Chokingdogs]

simple answer. YES.




(that means a boosted LS...)


I'm doing an LS swap soon in my 944...cant beat the power/available upgrades for the cost.

Yeah, the LS- series engines are tough to beat from a PPD ( performance/power per dollar ) perspective. An honest 500 crank HP is easily attainable in NA configuration. The aftermarket is chock full of bolt-on, go-fast, goodies. Manifolds, injectors, heads, NOX systems, cams, ECUs, etc...

The biggest "problem" one can expect in doing a hi-po LS- swap, is keeping traction and not breaking every driveline part on the car, LOL.

Exhaust may post a challenge if running true duals with cats, but large cross sectional oval exhaust tubing ( like what the NA$CAR boys use ) is available.

[gk325is]

Counter intuitive I know read somewhere that formula 1 cars use 100k+ blocks for that reason.

This used to be true in the 80's when they used engine blocks from production cars. Those engines were also 1.8 liter turbos four cylinders making well over 1,000 hp in race spec and where capable of more like 1,500hp. There are only a few companies that make the engines now Ferrari, Mercedes, and Cosworth and all of them are new purpose built engines.

With that said teams do run all the engines in practice it check them but most engines will only go a few hundred miles.

OP: If you are comfortable fabricating and have to have that NA tq then swap a LS. If not get a good kit for a turbo for the s52 and save yourself from having to put in an engine not designed for your car.

[Moron95M3]

^^You left out Renault! ;)

and a few hundred miles = two full race weekends...more like a few thousand




OP....why not get an M3...don't mod it, do maintenance, track it and see if you think it needs more power first?

[gk325is]

^^You left out Renault! ;)

and a few hundred miles = two full race weekends...more like a few thousand


Each race is 190 miles they do about 2 races each motor and probably another races worth of driving in practice. They max out at 600-800 miles a motor maybe a 1,000.

And your right I did forget about Renault, especially since there motor is dominating!

[breakfast]

These motors take very well to boost at any mileage. Depending on power all you'll need to do is get a different head gasket and not worry about the internals.

headgasket problems plague these things. though the proper forumla seems to be OEM hg, proper studs and copper o ringed.

but its definitely an issue if yo dont have things set up right.

[Volf]

headgasket problems plague these things.

I thought that's what I said? :confused

[MasterKwan]

For road racing, I'd probably lean towards the LSx motor since it would be less stressed, unless you were willing to fully build the S52 turbo (meaning much greater costs).

DEing ain't road racing. Just say'in. My question is, how much DE experience does the OP have? If none, then taking a high powered car to the track is a bad idea. You'll be slower than the Miata's, which is embarrassing enough and you'll also probably put it into a wall and have to tow home a box of metal. If you turbo or LS swap it, you'll probably never road race it either. Can't think what class you might be in.


Watched a 400 Hp 335 tag a wall Monday. At least 10K in damage.

[KnudsonsM3]

+ twin turbos.

too much power!

you can make an LS motor get 500 hp with mild head and exhaust work

[Tongboy]

DEing ain't road racing. Just say'in. If you turbo or LS swap it, you'll probably never road race it either. Can't think what class you might be in.
It's very true, I did my swap for track reliability but the issue now is anything competitive is finding the correct class, almost always it means unlimited or close to it class and those take $$$$ to compete in.de days are of course different but the more I get into the sport the more wheel to wheel looks to be the place to go and that means strict class car.

With a swapped our turbo car you'll be limited to crazy classes or fun but not main stream racing, think hill climbs & related, places with much vaguer class structures.




too much power!

you can make an LS motor get 500 hp with mild head and exhaust work

Not easily, at least on the more common sized 5.7l motors, sure on an ls2 or bigger but 500whp on a 5.7 isn't cheap or super easy to get to, mid 400' s is a lot more realistic depending on power band goals

[KnudsonsM3]

im referring to crank hp, not whp.

[Ritt]

Having done the high-output turbo thing (albeit on another car, not my M3) I'd go the LSx route in the E36. More power for less stress on the engine and car in the long run.

My $.02

[RahgBag]

LS1. But I'm biased :P