IE Stroker Kit vs S50

[TexasTerp]

I'm working on putting together a worksheet for an engine build I would like to build next summer/fall. I am considering an S50 swap but I came across Ireland Engineering's Stroker kits and am intrigued. I'm particularly interested in the 3.1L Kit. They claim that you can "Turn the 2.5 liter 325i (m20)motor into a 3.1 liter for performance beyond a E36 M3. The additional torque allows the engine to pull strongly below 3000 rpm. Kit includes crank shaft with 89.6mm stroke, light weight forged Pistons, piston rings, high strength wrist pins, and main bearings." You can use your "i" rods or buy new high strength ones. All for 2k.

I would like to limit my budget to anywhere between 5-7k, preferably on the cheaper side as I still need a paint job and suspension first. So here's the thing, if I stick to 5k in parts I could either buy an s50 (an engine that I have limited experience working on) or I can have my spare block machined, honed and bored to spec and build a "new" 3.1L m20 (one that I've worked on my whole life, literally) with supposedly the same power output and have multiple upgrades on top of the kit.

Here's the build I was thinking of based on approximate pricing at 5k:

IE 3.1L Stroker Kit
M42 Radiator
Miller WAR Chip and MAF
Custom ITB Build
Custom Fiberglass Airbox for ITB
8mm Performance Ignition wires
19lb Fuel Injectors
Performance Headers (Ebay? BavAuto?)
Electric Radiator Fan
Scorpion/Stromung/UUC/Supersprint Exhaust (or Custom build)
Wideband 02 Sensor

now clearly I'll need plenty more little things like new motor mounts etc. The biggest advantages I have with the stroker kit is it's a direct drop in, I've owned my m20 325i since it rolled off the lot in 87 so I have far more experience with the engine, I can still use the Motronic system inline with the WAR chip and have it custom tuned (saves me from having to deal with a more complicated MS system) and I'll be able to do the entire swap without any major worries since I've never done an m/s50 swap before and have no desire to fuck anything up (which would mean me paying someone else to do it), I've rebuilt an m20 before.

So what do you guys think? 3.1L Stroker or S50? Has anyone ever bought an IE Stroker Kit??

[Justin B]

Not sure exactly how they'll line up side to side, but I bet the S50 will still have some sort of advantage. On top of that, good luck staying under 5k, ESPECIALLY with some custom ITB's, unless you're going to just use motorcycle throttles. You could piece together your own IE kit for either less OR more depending on what components you use, and what you ultimately replace in the engine during the rebuild. My bottom up engine build building my own "kit" with the S52 crank and Metric Mechanic bits, I'm already well over 5k without machine work, new rockers, or ITB's.

[Wh33lhop]

If you're going to throw a motor together from scratch don't forget to choose a cam--and I'm not sure if 19#ers will be enough for you. Select few that I'm aware of have actually put together an aftermarket stroker (if any on here), so you'd be one of the first and you'd certainly have a unique car.

You say you've owned your E30 since new--how old were you when you bought your car?

Edit: Good point, I read right over the ITB plans. The Dbilas ITB setup goes for well over a grand if you can get your hands on them (last I saw was priced at $2k), either way that's a huge expense on its own. You have probably figured this out by now, but as with everything, you're going to spend a lot more than you expect on this if you actually go through with it.

[Unearth078]

on your budget i really couldn't see the stroker being done. as you know theres going to be alot of modifications needed to be done to the head to support the bottom, schrick cam, enlarged valves etc.

power maybe dissapointing as well, while you may make 200 hp (optimistically but doable), the s50 has a little more in store right away, sure its a little out of your comfort zone tho

if you shop around for the swap parts i think you can do it without hitting 5k.

[reelizmpro]

In this case I would go for the S50 because in all these years, I have yet to see a 3 liter M20 run right without detonation or reach 200rwhp without major mods. That Ireland kit came out years ago, yet there are only a few 3.0 liter M20's running around. You can run ITB's with no AFM but you'll still be limited by 2 valves per cylinder. Then there's the timing belt. The one thing that is good, is that you'll have a rebuilt engine and you don't have to convert anything else. With the S50 you get a newer engine, 24valve DOHC head and a reliable 240-260HP easily. The "bad" is it's a used engine and you have to do a swap. Add up the costs and decide for yourself.

[z31maniac]

Edit: Good point, I read right over the ITB plans. The Dbilas ITB setup goes for well over a grand if you can get your hands on them (last I saw was priced at $2k), either way that's a huge expense on its own. You have probably figured this out by now, but as with everything, you're going to spend a lot more than you expect on this if you actually go through with it.

Dbilas is well over $3k for a new setup, there is another company doing E30 ITB's with quality stuff (search for a thread I started awhile back about it).

I did all the research on this already, rather than build a 3.1L M20, we are getting ready to stuff an OBD-I S52 in my car.

[BeirBrennerE30]

so you could have a stock s50 with great driveability and room to add more power in the future OR essentially a built to the hilt race motor with no room to go with the same power as the stock s50

there is no question here

[Massive Lee]

Buying the base kit is only one part of the process. On top of the ITBs, the fueling system must be adressed (bigger injectors), increased cooling, oiling, as well as the engine management and dyno tuning. Add everything together, and you end up with a hefty bill, and 30 year old technology. And you will still be short of the S50 reliability.

[Tricked 323i]

I have driven both a built up 2.7 stroker, 200whp and a built up s52, 255whp.
The 2.7 stroker was quick and he about 8k in the engine. The S52 just blew it away and he had about the same cost in it. I have all the parts to build a 2.7 Racing dynamics stroker and a OBD1 s52 for my cabrio. Guess which one I am going with.
Kevin

[sticksdaman]

Timing chain > Timing belt

'nuff said

[dude8383]

im going to have to agree with everyone else here, 24V will make you much happier in the end.

[TexasTerp]

Well it sounds like the consensus is the s50/2 hands down. I'm still in the midst of a lot of research for both engines. plus I'll still have to acquire an s52 engine and all the extra parts needed just for the basic swap (e21 booster etc etc). One of the main reasons I was interested in the stroker is because I was going to do a 2.7 and happened upon the IE kit, I've also been witness to a few m50 swaps in my area lately and they have had nothing but problems, I don't do anything half assed but I would be doing the swap myself.

On top of that, good luck staying under 5k, ESPECIALLY with some custom ITB's, unless you're going to just use motorcycle throttles.

I would be building the ITB system using motorcycle throttles as I've seen some people do here.

You say you've owned your E30 since new--how old were you when you bought your car?

it was late, I should clarify, I'm 24, my dad bought the car off the lot in 1987 (still have the original contract) and I've been working on this car since I was able to hold a wrench. 280k on the original engine!

on your budget i really couldn't see the stroker being done. as you know theres going to be alot of modifications needed to be done to the head to support the bottom, schrick cam, enlarged valves etc.

power maybe dissapointing as well, while you may make 200 hp (optimistically but doable), the s50 has a little more in store right away, sure its a little out of your comfort zone tho

so you could have a stock s50 with great driveability and room to add more power in the future OR essentially a built to the hilt race motor with no room to go with the same power as the stock s50

Well according to what I've been told by IE (I emailed them), the kit is a direct replacement and is supposed to make 240hp without any other modifications other than machining the block for the over sized pistons. They recommend a better cam but larger valves aren't necessary.

Both setups would leave me with the option of boosting, but I'm not that interested since this is my daily.

The one thing that is good, is that you'll have a rebuilt engine and you don't have to convert anything else. With the S50 you get a newer engine, 24valve DOHC head and a reliable 240-260HP easily. The "bad" is it's a used engine and you have to do a swap. Add up the costs and decide for yourself.

If I decided on the S50 I would end up doing a major rebuild on the engine. I don't trust just throwing it into the car. So that means new gaskets, machining, pumps, injectors, etc, etc. there's another 2k at least added to the parts budget.

I did all the research on this already, rather than build a 3.1L M20, we are getting ready to stuff an OBD-I S52 in my car.

You're the person I need to talk to then, what were the factors that made your decision to go with the S52?

Buying the base kit is only one part of the process. On top of the ITBs, the fueling system must be adressed (bigger injectors), increased cooling, oiling, as well as the engine management and dyno tuning. Add everything together, and you end up with a hefty bill, and 30 year old technology. And you will still be short of the S50 reliability.

5k is just my parts budget, tuning and everything else if already accounted for and on top of the 5k. My original post already addresses many of the other aspects (fuel injectors, cooling etc) within my budget. I have seen a couple s50 swaps in person and along with the m50 swaps all I've heard is people have problems. this may be because of the quality of the swap or for whatever reason, but all I've heard for the past months with friends doing these swaps are people have been having way to many troubles with the engines themselves.

I have driven both a built up 2.7 stroker, 200whp and a built up s52, 255whp.
The 2.7 stroker was quick and he about 8k in the engine. The S52 just blew it away and he had about the same cost in it. I have all the parts to build a 2.7 Racing dynamics stroker and a OBD1 s52 for my cabrio. Guess which one I am going with.
Kevin

2.7 and 3.1L strokers are miles apart. I have the ability to build a 2.7 seta stroker for far less than 8k. I would absolutely expect the S52 to leave the 2.7 in the dust. There's no comparison.

[Tricked 323i]

2.7 and 3.1L strokers are miles apart. I have the ability to build a 2.7 seta stroker for far less than 8k. I would absolutely expect the S52 to leave the 2.7 in the dust. There's no comparison.

Sorry wrote it wrong. 215-220whp and your 3.1 is 240 crank. Your 3.1 is less whp. A 2.7 eta stroker might do 185 crank with stock internals and stock ecu. The 2.7 stroker I drove was far from stock.
Kevin

[dude8383]

what kind of problems are these guys having? my motor has been trouble free apart from an oil leak from the oil filter/oil pump location.

[87e30]

I'm currently in the middle of an m52 swap. I know quite a few people in the local area that love their 24v swaps.

I was kind of in the same pickle as you, except less power and less budget.

I was thinking budget stroker (b25 head) or m5x. The way I saw it I wanted my car to feel newer. I figured the newer motor with 24v would be smoother, more reliable, and have a better throttle response.

Granted I've never driven either, but I think this is something worth thinking about.