16v 3.0 in 944 Turbo Surprises?

[944m3]

Not an easy road for sure.

That being said, I don’t think I’ve ever read someone regretting building a 16v turbo (once they’ve experienced the performance vs. an 8v). Is that a fair statement?

[Tom]

Not an easy road for sure.

That being said, I don’t think I’ve ever read someone regretting building a 16v turbo (once they’ve experienced the performance vs. an 8v). Is that a fair statement?

I'm sure that's true, but I have to put in a plug for us 8v 3 liter guys. An 8v 3L with the right set up can be incredibly powerful -- honestly, it throws the chassis out of whack without significant upgrades. You have to think of the whole package to end up with a fun and reliable car -- clutch, brakes, suspension, squat, cooling, gearing, axle strength, CV strength, tranny strength, engine management, engine ancillaries, fuel flow, and on an on. The more you push the power, the more it will cost to support it. And if you don't plan ahead, like I didn't for the most part, you literally find the next weakest link one blown-up part at a time.

[Bergerac]

I wonder if we've hit the tipping point where its easier to get 16V heads than 2.7 8V heads. At least the Mahle motorsport 8V 968 turbo pistons are still available off the shelf

[Thom]

The amount of effort required to build a 16V turbo engine probably depends on one's experience with previous 944 engine builds. I can only bow to anyone attempting a 16V turbo build "from scratch" and if I could travel back in time when I was into the build of my 8V engine then I would still not consider a 16V engine as without the knowledge and experience acquired since then the results would clearly not have been as good as they are today, or it would have cost far more time and money to get there. The way forward to building a sound 8V engine is pretty much mapped out these days and should already not require much if any intake/exhaust welding as with a 16V engine.

[Jotronic]

I guess to summarize;

- Intake manifold clashed with coolant elbow so I had to make custom coolant lines,
- Turbo coolant line/temp switch clashed with intake due to bigger turbo so it had to be modified
- Turbo coolant pump clashed with turbo intake so had to be moved and now clashes with my strut brace
- Turbo inlet clashed with Nissan alternator, no fix for that, the silicone intake hose pushes up against the terminal. Will need to investigate a different alternator at some point.
- Heat shields around the turbo had to be modified to fit
- AOS outlet clashed with inlet manifold, and hard vacuum lines dont fit. Not a big issue as Ive deleted most of the stock vacuum lines but you will need to go DBW to delete the ICV.
- I ended up with a turbo oil pump, this is not compatible with the 16V timing belt arrangement, and there was another issue with the lower balance shaft end cap/power steering mount which I cant exactly remember but I had to swap it off my S2 motor.
- Depending on your intake manifold/throttle body choice you will need custom intercooler pipes.
- Issues getting the exhaust manifolds/crossover modified to work together ( trying to weld old dirty heat cycled SS)
- Custom harness to combine the turbo/16V differences (cam sensor, 2x knock sensors, single speed/ref sensor, high low injectors/ballast, . May as well go fully sequential while you're at it)
- Custom pistons which are expensive ($1300+shipping/taxes from Mahle)
- Ended up being cheaper getting custom valves made than buying originals from Porsche, and very hard to get heavier springs if you want to go that way, Cat Cams is basically the only option.
- No room for turbo filter/airbox so custom piping to filter in bumper.
- Modifying the upper balance shaft housing for turbo oil feel.
- Modifying sump for turbo oil return of not already drilled.
- Custom dipstick tube to clear turbo/manifold.
- Custom fuel lines FPR/Damper to suit manifold/fuel rail.

Im sure there is others that Im choosing to forget plus multiple times I've wanted to drop a lit match down the fuel filler and walk away. Youve got to remember that even though you're getting a deal on the motor ,there's no guarantee you wont need to get it sleeved or nikasealed, there's no issues with the cams or the head like you've already experienced ,is the crank in spec? I started out with the plan to rebuilt my S2 engine and ended up buying a brand new 968 block and head because there was simply no one close to me that I could trust to work on my block and it ended being cheaper than shipping overseas to get the work done.

I'm supremely grateful for your putting this post together. It helps because it shows me more of your frustration, but also shows I've got much of this covered with my approach. The block absolutely will be sleeved and if the crank or anything is out of spec, it'll be addressed. We're not planning on simply slapping in some rods and pistons and a turbo. I'm working with a shop that has built these before and the owner has one himself, also from an S2. He's a fabricator as well and owns the car featured in the video below where he swapped in (for a while) a Mazda V6 before reverting back to the S2 motor.



His current motor with an in house fabbed intake and IC piping.



Again, I am really grateful for your input on this, Bergerac. You've given me a lot to think about.

[Jotronic]

Not an easy road for sure.

That being said, I don’t think I’ve ever read someone regretting building a 16v turbo (once they’ve experienced the performance vs. an 8v). Is that a fair statement?

I'm sure that's true, but I have to put in a plug for us 8v 3 liter guys. An 8v 3L with the right set up can be incredibly powerful -- honestly, it throws the chassis out of whack without significant upgrades. You have to think of the whole package to end up with a fun and reliable car -- clutch, brakes, suspension, squat, cooling, gearing, axle strength, CV strength, tranny strength, engine management, engine ancillaries, fuel flow, and on an on. The more you push the power, the more it will cost to support it. And if you don't plan ahead, like I didn't for the most part, you literally find the next weakest link one blown-up part at a time.

Thanks for your thoughts on this, Tom. I was originally going to go with the 3.0 8v, then decided to use what I have and make a 2.8 stroker. I have the crank, but when I started speaking with my builder I started to think more about the 16v motor. In fact, the build of the 16v motor itself was surprisingly less expensive than the 8v options due to the lack of need for significant head work compared to the 8v head. I know that cost will be equalized or maybe go higher once I get everything sorted as far as the details, but

Regarding my chassis; The suspension and brakes were the first things I addressed starting two years ago. Suspension has all Elephant Racing sport rubber for bushings. Sway bars are larger Weltmeisters (sp?), wheel bearings are all new, transaxle was resealed along with having a Wavetrac LSD installed. But, I have a 01E swap kit coming from http://www.lobb.ltd/audi-01e-to-porsche ... rsion-kit/ and will be working with Drivesport.ca in Toronto build a 01E for me. The kit comes with chromoly shafts and upgraded CVs. Brakes are 996tt with 997 discs.

But Hell, I may just wind up having a stock motor built with lighter pistons and a bigger turbo then crank up the boost and call it a day.

[Jotronic]

The amount of effort required to build a 16V turbo engine probably depends on one's experience with previous 944 engine builds. I can only bow to anyone attempting a 16V turbo build "from scratch" and if I could travel back in time when I was into the build of my 8V engine then I would still not consider a 16V engine as without the knowledge and experience acquired since then the results would clearly not have been as good as they are today, or it would have cost far more time and money to get there. The way forward to building a sound 8V engine is pretty much mapped out these days and should already not require much if any intake/exhaust welding as with a 16V engine.

Well that certainly is the beauty of sticking with an 8v motor. I can keep my SFR stage 2 headers and even my stock intake, even if I went with a 2.7 8v and just modify the intake runners. Again, your experience is in my thought process.

[Jotronic]

This is the basic build outline from the shop I’m talking to. The variables include the turbo and the intake. The builder is suggesting using the stock exhaust manifold and fab an adapter to the crossover or the SFR option.

We are talking about mounts for the turbo where I’ll use a stock mount or a mount from Tial/Xona for one of their turbos. AC, PS and alternator (Nissan) will swap over. Some coolant hoses will need to be changed.

IMG_6259.jpeg (716.45 KiB) Viewed 269 times

[Bergerac]

I guess the main takeaway from my post above is packaging around the intake side is the challenge, it's a very expensive game of Tetris trying to get a larger turbo and a custom intake just right. You can't assume any of the stock equipment on that side will fit and there's a lot stuffed into that space.The order of execution is critical ind one little mistake and you're back to the start. ie no point buying a harness until you decide if you need to delete the ICV

The engine build side follows much the same formula as the 8v, it looks like you have this covered (as long as the sleeves are done right, many tales of woe around this) and the exhaust side is simple enough.

Thoms comment is very true about experience being critical , I jumped in both feet first with my rose tinted glasses on and was very lucky that my partner in crime is a mechanic with 50 years experience and I'm an instrument technician so we could solve most of the problems ourselves. I would be a very poor man if I'd paid someone else to do it.

[Jotronic]

I guess the main takeaway from my post above is packaging around the intake side is the challenge, it's a very expensive game of Tetris trying to get a larger turbo and a custom intake just right. You can't assume any of the stock equipment on that side will fit and there's a lot stuffed into that space.The order of execution is critical ind one little mistake and you're back to the start. ie no point buying a harness until you decide if you need to delete the ICV

The engine build side follows much the same formula as the 8v, it looks like you have this covered (as long as the sleeves are done right, many tales of woe around this) and the exhaust side is simple enough.

Thoms comment is very true about experience being critical , I jumped in both feet first with my rose tinted glasses on and was very lucky that my partner in crime is a mechanic with 50 years experience and I'm an instrument technician so we could solve most of the problems ourselves. I would be a very poor man if I'd paid someone else to do it.

Makes PERFECT sense what you're saying. You've really helped me to step back and think more about this. Thanks again for your perspective.