Turbo or 3.0 Stroker?

[chameleonleather]

This is exactly the insight I'm looking for. At this moment the M20 is going through a rebuild and I'm torn between building a stroker or build it for turbo. Most people say turbo of course, but that’s 70 lbs up front! In my opinion it is one thing going fast in a straight line and another driving fast on the track or autox. I would love the extra 50hp from the turbo but this is also a DD. I would love some more guidance. It's going to cost me 6k either way with Mega Squirt and tune. With the stroker it will be all new parts with s50 crank and custom pistons, cam, rods, rockers and springs (the whole nine yards)...and with the turbo it will be a stock rebuild salvaging as much parts as possible and using a comatic gasket.....I'm leaning towards the stroker just for the "new" factor alone.

[Jon325i]

Both are tempting propositions - of course, the ultimate solution would be to build a 3.0L stroker with turbo :)

Going with the stroker route, the mechanical complexity of the motor is going to remain largely unchanged. You mentioned doing MegaSquirt (a good thing) but aside from that it should be as durable and no more complicated to work on/maintain than a stock M20. I've had a chance to ride in a E30 with a 3.0L M20 and although it wasn't totally finished off and tuned well, it still had an impressive amount of torque down low which made for snappy take offs.

With the turbo, there's obviously more "stuff" bolted onto the engine and maintenance & repairs may become a bit more involved to do depending on how the forced induction set up is installed in the engine bay. No doubt this would be a fun package to run and you can set it up conservatively with a smaller snail to bring on boost early for better low end grunt (like a stroker) or go for more mid-range and/or top end punch. Of course, if you go with a more extreme turbo set up many internal changes will need to be made to cope with the stress expected. Check out http://www.turbochargingdynamics.com for a nice set up - albeit at a price - which it set up to work with stock M20 internals.

I guess which one to go with is going to boil down to your preference and driving style. Some like the power down low, others prefer maximum fun as the tach nears redline.


Jon

[chameleonleather]

With the turbo set up it would be built to hit peak torque by 2.5k. Everyone I talk to says if I go with turbo I will be itching for more and more boost, hence more wear and higher cost in the long run. I have taken rides in a 3.1 stroker 2400lbs e30 race car and it's just silly fast. And it wails like a banshee.

[etxxz]

6k?!

s52 swap.

m20 turbo for auto-x is not great. on the track is just about setting up your car suspension. that's what coilovers are for...weight transfer

With the turbo set up it would be built to hit peak torque by 2.5k. Everyone I talk to says if I go with turbo I will be itching for more and more boost, hence more wear and higher cost in the long run. I have taken rides in a 3.1 stroker 2100lbs e30 race car and it's just silly fast. And it wails like a banshee.

and how in the hell do you make a 2100lb e30?!

[mikeedler]

dude, I have no idea what you are want to use that adds an extra 70lbs.-- my turbo cars turbo manifold is lighter than the stock, the blow off with alu. piping weighs about 5lbs and the turbo with the wastegate weighs nowhere even close to 25 lbs.-- and you will get alot more than 50hp if you do it semi correctly.

i say turbo if you want to go fast, but if you want it for curves dont get a very large turbo.- if you want something to track, probably without turbo- i dont like driving my turbo car in the twisties at all- it comes on to boost at any given time and if your in a curve it sure makes it interesting.

for the money you will get alot more hp for you $ out of the turbo

[chameleonleather]

6k?!

s52 swap.

m20 turbo for auto-x is not great. on the track is just about setting up your car suspension. that's what coilovers are for...weight transfer

and how in the hell do you make a 2100lb e30?!

Sorry 2400lbs. Although with a M42 set up 2100lbs is not unheard of. Basically bare shell with some panel cut away or replaced with lighter material.

[318isbmw]

I agree w/ mike. Been in a turbo e30 and it was scary as hell when the thing hit boost in a curve, and it was a dinan so it was built for reliability. If you wanna autox I'd personally go w/ a stroker.

[z50_Jumper]

Im thinking stroke it. Nice and smooth

[Justin B]

Strokers are awesome, and I am building one but I admit they are probably one of the least cost effective ways to make power. Just because slapping a turbo on could be so much cheaper and make even more power. It comes down to how you like your power band. Either way with a stroker or turbo set up, you're going to need to make use of another ECU whether thats Megasquirt, VEMS, or any of the myriad of other's available out there. I'm going to use a DTA S-80 Pro FWIW.

[mikeedler]

how about a turbo stroker?

[gearheadE30]

I am a huge fan of NA motors, so my vote went for the stroker. I like the power delivery, and I am an autocross guy. Either way, though, it would he hella fun.

[chameleonleather]

I'm very impressed with the response guys, thank you very much. The mega squirt is already build and ready to go. If I go with the stroker and later on I want to go with boost for more power, do lower compression pistons need to be put in? Or would a thicker comatic head gasket suffice?

The cost of the stroker will end up being a little bit cheaper then the turbo, because of the head being cracked I do require a rebuild before putting in the boost.

[Edev]

stroker.

[Kilomph]

A freshened stock M20 with a TCD setup would be just as reliable, and just as easy to maintain. I don't see why a TCD setup would require anymore maintenance than a stock M20. The turbo will last for a very, very long time. Keep boost limited to 12 PSI, don't dump the clutch, keep up with basic maintenance and you're solid.

Plus a TCD setup with 12 PSI will reliably make 300+WHP, unlike a silly 3.0 stroker which will most likely struggle to make over 200. Turbos are nice and smooth, a 3.0L stroker will have an extreme cam and lumpy idle.

If it's an auto-x only car, there's no question, you should go stroker. For auto-x you want the engine to respond, you don't want to wait at all for the turbo to spool. Of course you could get a small turbo, but it seems like people always end up going bigger because it creates a butt plug.

[CleanAzzE30z]

Make it interesting. Im always for N/A. Takes more skill to make power without forced induction. Thats my opinion so dont get upset if you have FI.



Mariano