750-800hp 944 S2 3L 16v

[Breizhtetics]

Hello everyone,

I have read almost everything online about putting a turbo on a M44 3L 16v engine, especialy all of your topics @Thom @Bergerac and @333pg333 and i can't stop thinking that with proper preperation, those engines could withstand so much more than what have been done to it.

Let me introduce myself, i'm a french aerospace engineer and i would like to build a rocket for the track (and i'm not even joking lol). About 2 years ago i bought my first 944 and 3 months after i broke the engine on the road to the nurburgring. N2 rod bearing decided to fuse into the crank. After a deep thought about my life decisions i repaired everything by myself and it was a huge success, and then i broke the gearbox.. lskdnvanvqqkvn. The thing is that i continuously dig more and more on internet about those cars and my toxic relationship with my car didn't help because i couldn't stop thinking that i should sell it.. and then that i could repair it and then fix it after it broke again and god damn it happened a lot. Anyway i fell on some old forums with Rogue_ant speaking about the reverse-engineering he has done to the ECU that lead to the insane focus9 DME, the turbo he puts on a NA engine with everything else stock and ran 350hp with a daily use during 9 months before the rings FINALY explode.. anyway those engines have potential and we know it, especialy those 16v that have been shuned by the turbo community.

And then earlier this year, after my classic browse into our french marketplace, i found it, the potentiel project i have ever dreamed of. A 944 S2 chassis prepared for the track and the engine, the 3L 16v. After a deep negotiation with my girlfriend i jumped on the occasion. So here we go : I know that what you will read now is ambitious, but let's dream together before the reality catches up. Here is my ideas :

- Garrett GTX3584RS with 30 psi of boost
- Carrillo rods
- Custom Pistons 8:1 (i have to find a manufacturer or i will just put 2x3mm headgasket.. maybe not lol)
- Epoxy54 resin closed deck
- Stock engine stud (thom's engineering for the victory)
- bat 20.1l/min Cordis 3 Stage dry sump pump with custom crankcase and everything
- balance shaft suppression
- E85 gas
- 1800cc injectors
- Water injection
- oil squirter modification based of the 968 design for piston lubrification
- 01E gearbox
- Maxxecu
- VW vr6 hydraulic lifter (lighter than S2 one and pretty cheap)

I'm thinking about keeping the head stock beside the VW lifters because peak horsepower should be around 7000rpm and the stock head "should" be able to withstand that AND i heard that solid lifters and stiffer springs are prone for cracking the head. I also won't go with the 968 head because of the heavier intake valves (and I couldn't find one lol).
Furthermore, i plane to keep the alusil surfaced cylinder. HOLD ON and hear me out, dry sleeves tend to keep the heat, and the resin closed deck, in my opinion, acts as a much more reliable cylinder reenforcement but also doesn't help with heat dispersion, so i will need that extra potential of heat dissipation that aluminium cylinder is able to give. Darton wet sleeves is i think the perfect choice, but hey, i don't have unlimited bank account so lets try resin + alusil. I keep the idea of the darton sleeve for a 1000hp m44 lol.

SO, what does your expert eyes have to say about that ?

PS : I plan to do it regardless of potential bad critics so prepare your " TOLD YOU" for when my engine blows up
PSS : If you have solid argument of course i will listen, i'm not that dumb, but so much bad info have been around like "gngngn ethanol is bad for 944 engine"... actually it's quite the opposite but i keep that for another typic lol

[PSU_Crash]

Go crazy! Document everything and I'll get the popcorn started.

[Bergerac]

Welcome to the club! The S2 is really a great platform for this, it incoporates a lot of imporvements that the early Turbos didnt have and all the mounting points for the extra turbo parts are all there.

There are Alusil piston options out there, Wossner had some issues with coatings but Ive heard that has been rectified now and I havent had any issues so far with my Mahle Motorsport pistons. One benefit of liners is it really opens up your options for piston manufacturers if you have someone who is compentent at installing them. I couldnt find anyone close to me I trusted without shipping my block half way around the world.

Honestly 500-600hp will be more than enough for these cars (my cars already hilarious at 9psi), I think with the turbo youve chosen you will need to look at serious head/cam/valve mods to push past that anyway. Seems like most of the higher HP builds broke the block in the end, its much more fun driving a 500hp car that is reliable!

Im no expert by any means, but I did spend a lot of time reading through other peoples builds to see what worked and ignoring people who told me to not waste my time.

[Breizhtetics]

Seems like most of the higher HP builds broke the block in the end

Do you have more info on that ? I heard thom speaking about a guy breaking the block at 950Nm but couldn’t find anything, did the block get reenforced ? Where did it broke exactly ? I didnt saw any 944 build with broken engine after top deck plate reenforcement and nothing at all with the resin one.

Also, Turbotim documented his built on rennlist in 2013 and get close to 700hp with liners and no top deck plate.

I know that 500hp is more than enought to have fun, but science you know

[Thom]

Welcome and good luck with your project. It is quite a long way to get there but well worth it IMO.

If I remember right Duke made near 950 N.m on his last dyno run before heading to World Time Attack in Sydney where the block broke as suggested by photos showing the girdle had "pulled" one or two bottom main studs out. The material in the block around the main studs cracked. It is also possible he turned up the boost to be as competitive as possible and we won't know for sure how much torque the engine was making when the block broke.

500-600 hp is I think well enough for a 3L for road use. More hp may make sense on a shorter stroke engine (maybe 2.7 16V) that would make less of the barely manageable peak torque of a 3l. At least that's what I would build for a track car.

Good luck and let us how you get on.

[Breizhtetics]

Ok found it, can’t believe i didn’t fell on it with all the researches that i’ve done
I didn’t plan to drive this one on the road, i have my N/a daily drive 944 for that.
I thought about de-stroking the 3L with a 2.5 crank, making it a 2.68L, but what should be the the optimal static compression ratio and boost to still get more than 700hp at 7000rpm ?

[Thom]

what should be the the optimal static compression ratio and boost to still get more than 700hp at 7000rpm ?

Well, how long is a piece of string...

[michaelmount123]

Sounds like a fun project!

If your goal is maximum HP, why in the world would you de-stroke the 3L? I see no value add. Perhaps you could get to the same peak power but you'd stress the smaller engine significantly more and reliability becomes a bigger issue. More importantly, the larger engine will have much higher average HP in the rev range used on the track and will be lots quicker than the smaller engine.

For the street guys who are breaking things or spinning tires, manage the power at any particular RPM with the EBC and/or ignition timing via the ECU - not by building a smaller engine.

Just my .02,
MM

[Bergerac]

But spinning the tires is fun Michael.

If you have to start pulling boost and or timing your car is telling you you've got too much power.

[Breizhtetics]

If your goal is maximum HP, why in the world would you de-stroke the 3L?

Those engine produce a lot of torque, and if you want the maximum hp, the massive torque in response create too much stress on the crankcase

(This is what happened at 946hp 966Nm)

IMG_2924.jpeg (272.89 KiB) Viewed 271 times

IMG_2923.jpeg (186.89 KiB) Viewed 271 times

Reducing the stroke means less torque for the hp, means more potential hp

The second added value my eyes see is that reducing the stroke also reduce the compression ratio, and with a 2.5L crank in place of the 3L and a 3mm cometic headgasket you now have a compression ratio of 8:1 with piston meant for 10.9:1
So no more need for costum made piston