I'm at a cross roads regarding what kind of build I want to do from scratch. I am aware of how reading till my eyes are crossed can generate ideas of grandeur when it comes to motor swaps but I need some real world experienced input.

My conundrum is this. Stick with the 8v approach and push it to the higher end or pull the trigger on a 16v 3.0 build? I'm this close (imagine a small space) to pulling the trigger on the 3.0 16v turbo motor build option because I have a deal for a complete S2 motor freshly pulled for half the price of a turbo motor, less even. Seems like a no brainer, but with the experience I've gained from just adding aftermarket parts to my stock motor, and the headaches that can go with them, I know it won't be simply dropping my old motor and raising up a new one in it's place and turning the key to go.

I'm seeking a definitive list of things from my stock 2.5 motor that will or will not swap over to my 3.0 16 turbo motor. My car is a street car so I want to keep my power steering, my AC (upgraded to the Griffin unit), my Nissan alternator mod etc. I've been told these will bolt up.

I will get a new exhaust manifold (sfr) and intake manifold. I'll get a new harness from Bas and I have already a MaxxECU Race. My turbo will have to be bigger so while the stock turbo mount can swap over(?), I need a turbo bigger than my RaptorX.

What challenges can I expect during this swap? What swaps over, what doesn't?

Thanks in advance.

 

put simply
every external part/bracket that bolts to the engine block on your turbo will bolt to the block of the S2.
where 16v turbo builds get tripped up usually is with the exhaust and intake manifolds.
the 16v exh manifolds can be modified to use the turbo crossover pipe, not that big a problem
but the intake manifold gets tricky as there's only so much space, which gets eaten up by a large enough turbo to justify doing a 16v engine

i would not use any SFR parts at this point in time if you are buying new. Tim at SFR told me in person 10 years ago that he wanted to get out of the 944 game so i don't think there's as much "passion" in the parts as there used to be.

Hayward Performance in the last few years came out with a very nice looking, well-thought out, cast manifold for 16v turbos.

you will want a turbo clutch/flywheel. an upgraded stronger clutch kit is recommended.

- figure out how much power you want to make and how much boost you want.
- pick a turbo that fits those parameters and that you can bolt up (with or without modification) to the turbo mount
- get/modify an intake to fit above that turbo
- modify/make a downpipe to fit the turbo and clear the chassis
- modify the 16v exhaust manifolds to fit the 951 crossover pipe
- get a new wastegate
- get a 3" (or 3.5 or 4 depending on power) exhaust system
- get an aftermarket ECU to really be able to tune it, the stock stuff is not worth chasing

in basic turbo math if you add 1 bar of boost you double the N/A HP rating. say an S2 is 208hp so that would make 416.
however in actual practice the 16v head engines respond way better than that ratio suggests. 1bar gets you close to 450-500hp with a good turbo and intercooler. without doing any kind of porting or cams.

 

Really appreciate your reply. I already have new from SFR a set of stage 2 headers and two piece crossover, stage 1.5 intercooler, intercooler pipes with a Tial bov, and CAI pipes running to my RaptorX on my stock motor. With some of the things I’ve read, including your exact words when I was researching him, I took a gamble and he had my headers to me in a week flat when I needed a rush. The rest took some time because he did a number on his arm that required surgery but overall he’s been good to me. Exhaust is covered too with a 3” setup from Fabspeed along with their downpipe. I have a TialF38 that I’ll change out to an F46. For a new header for this build I’ll go back to Tim.

For the intake I’m not sure I want the Hayward unit, even with them operating half an hour from my home I’m considering the new intake from Bas Henneman or maybe a modified SR20 from a fabricator I found in Oz. All of that is up in the air at the moment till I make my final decision. I also have already a MaxxECU running my current motor so I’ll need a new harness from Bas directly or from Kroon using his designs. I also already have the Nissan Quest alternator mod for extra room.

That’s nice to hear about the boost on these motors. I’m looking to go to about 1.2 bar when all is said and done. I have the 01E swap kit from Lobb and am working with Peter at Drivesport.ca to have him build a new 01E for me with custom gearing, most likely a mix of 01E and 968 gearing. Turbo will likely be a Xona but am still looking at options. My builder is Blackbird Technical Services in Calgary, Alberta Canada where the owner has a similar motor in his car already and he built several already before. You can find him on YouTube where his car is being reviewed after he swapped in a Mazda V6 into his 951 and turbocharged it.

But yeah, good to know on the bolts and brackets point. That is what I’m concerned about so thank you for your time.

 

A 16v S2 head will drag the 944 turbo into the present day, performance wise. And that's from a 944 turbo owner, that has an 8v 2.7 engine and S2 crank sitting in my garage.

 

Appreciate your comment. I have a 968 crank in storage as well that I wanted to use for a 2.8 stroker. That'll be sold to help fund this build

 

Well obviously the easiest pain free swap would be stick with an 8v variant. A 3lt 8v is still a lot of fun and in some ways as much or more than the 16v that tends to get it's power a little higher in the rpms. I had a pretty modified 3.1lt 8v and it had a lot of tq and was easy to drive. But...is the 16v ultimately superior? Yes. One of the main reasons is that you can achieve the same power levels as a worked 8v but at a lot less boost and that's generally seen as a good thing. As discussed above, you don't have a ton of aftermarket options for the intake but I don't quite understand why you don't want to go with a Haywood intake as they're so close to you. Otherwise wait for Bas's and Sebastian's 16v version to come out. The modded SR20 from down here might be a cheap option but if it doesn't fit it may be a bit of a hassle to make work.

You'll also need pistons/rods and assuming you want to run in the stock alusil block you'll have to find some that work. I believe Wossner are back in the game. Or Mahle if you can get them. You can stick with the stock cams which are probably fine for a street car. JET951 still uses stock cams and he keeps up or beats GT3s on the track. Of course with all this new power you'll want uprated suspension and brakes and possibly larger wheels/tyres. So it's not a cheap pursuit but can be very rewarding if done correctly.

 

I think the 3.0 8 valve v 3.0 16 valve comparison is dependant on where you're planning to drive the car. Mainly twisty back roads, and the 8 valve is perhaps all you'll ever need. Track days or autobahn type roads, where you can really stretch the cars legs, and the 16 valve would likely win. If I was really set on a 16 valve turbo today, I'd start with a 968, a set of forged rods and machining the standard pistons would cut out some of the parts sourcing and expense. You'd have a 6 speed gearbox and a more modern looking car too.

 

Agreed. It's very purpose dependent. Yes, there would be a crossover of purposes. I think for 90% of most people's purposes a 3* 8v is sufficient. But the 16v is a better overall motor. Not to say you can't design a 16v to have more tq than normal either.
Having said all that, if I had my time again I'd quite possibly opt for the i5 Audi/VW platform.

 

You were asking about surprises. The exhaust manifolds from the 2.5 turbo do not fit the 16 valve head, the bolting flanges are a different configuration, and the exhaust manifolds from the 16 valve head do not fit the crossover flanges.

 

I'm surprised that you were surprised that the 8 valve exhaust manifold didn't fit a 16 valve head. Use the original 16 valve exhaust manifold, in the past someone was selling a adapter plate that mated the 16 valve manifold to the turbo cross over.

 

Not a surprise to me, I mention it because it appears the OP is planning to use a 4 into 1 header that was built for the 8 valve head.

 

No, in my original post I said…

In a subsequent post when it was implied I should avoid SFR because of something Tim said 10 years ago I said I have the headers now to share that I’ve had good recent experiences with Tim for my current order. I know 8v intake/exhaust manifolds do not work from 8v motors. Thank you.

 

I built my 16v 3.0L from an S2 good condition cheap base. It still turned out to be a huge never-ending project. I used 9:1 compression custom Arias pistons and a turbo that's too big for what I want. The car can make more power than I feel the chassis (and I can handle) and in comes in just like my old 8v engine... just more... a lot more. The nice thing with a modernized S2 engine is that it's still fun and quick out of boost.

I also won't deal with SFR after the terrible experience I had with Tim getting me parts.

 

Oooooh! Another Canadian car. Who built the motor for you?
Why is it still an unending project?
Which turbo did you go with that is "too big"?

That's the compression I'm looking at for whichever pistons I wind up getting. What kind of power are you putting down?

Grateful to hear back on this, thanks!

 

I built it in my garage before I had kids lol. The plan was to just do a little rebuild with shorter connecting rods and stock pistons with adapters for the exhaust flanges and modify a stock intake manifold... It ended up with custom forged pistons on stock length rods, with SFR equal length "stage 2" headers and crossover into a Precision 6062 turbo followed by the SFR front mount intercooler with custom piping into a modified 968 intake manifold. I use MS3X for engine management and basically started over with wiring and injectors, coils, boost control. There's really nothing stock left on the engine.
It put down around 370 at the wheels on a mustang dyno and it can do that on the race track pretty reliably... until something else lets go. Most recently I blew out the filter gasket and sprayed oil on the headers, which cooked some wiring. The megasquirt and tuning aspect is what I have been struggling with the most, specifically boost control. It's a really fine balance between a boost level that is reliable and overshooting it into overboost protection.

It's a lot of heat, power and old stuff that breaks. For reference, my race car is/was a N/A 968 powered S2 at around 240RWHP. That feels about perfect for me on track.