devgriff

I started this thread on the 968 Forum in June 2005. It seems there might be more interest in this topic on the 944T Forum.

https://rennlist.com/forums/showthre...light=3.0l+16v

I am starting this thread in the hope of it becoming a source of information for those who are planning to build and/or have built 3.? Liter 16 valve turbocharged engines for street and/or race applications.

This Thread should be used to share experiences such as cost of putting together a 3.? Liter 16 Valve engine (foreseen and unforeseen), custom parts required, clutch assembly, tuning and engine management, driving a 3.0 Liter 16 valve Porsche, dyno results, and etc.....

In no way at all this Thread is meant to or should be used to discredit the accomplishments of those who have or prefer 3.? Liter 8 valve engines.

I started this Thread because I feel there is more source of information available on Rennlist for "tried and proven" 8 valve engines than there is for 16 valve engines.

Thanks in advance to everyone who participated on this Thread, and please at all times keep feedbacks constructive.

devgriff

I recently completed putting together a 3.0L 16V engine for street application.

Below I have outlined the ways I attempted to resolve the typical drawbacks with 16V turbocharged engines.

Compression Ratio (CR)
Not knowing of the Heritage Motorsport 16V 8.?CR pistons, I decided to decrease the CR by using shorter connecting rods and a slightly thicker than stock Cometics MLS gasket. Squish area and rod ratio issues were taken into account prior to my decision to use this method to reduce the CR.

I used the 968 pistons as the service manual indicated that they were forged. The S2 pistons are cast according to the service manual.

Cylinder Head & Cam Chain
I used a 968 cylinder head because of its larger intake valves, and I replaced the cam chain with two front mounted cam gears. In order to use two front mounted cam gears, two exhaust camshafts had to be used.

Intake Manifold
I bought a custom 16V intake manifold off Rennlist classified. However, an affordable custom intake manifold can be made using the original 968 or S2 intake manifold for the runners and a 944T manifold for the plenum.

Exhaust Manifold
The 968 or S2 exhaust manifold was used. V-bands were used to connect the exhaust manifold to the 944T cross-over pipe. I also placed another v-band on the driver side of the cross-over pipe to make accessing the oil pan easier.

Speed Force Racing (SFR) sells excellent exhaust manifold and cross-over pipe.

A three piece cross-member is another good investment to make accessing the oil pan easier.

Clutch
I decided to use the 944T clutch assembly. In order to support 400+ hp, I choose a 930 clutch disk, KEP pressure plate (Stage I or II can be used), and lightened stock 944T flywheel.

Other Plumbing
944T oil pan was used and the upper driver side balance shaft cover was tapped for oil supply to the turbo.

The 944T oil filter housing was used for easy adaptation to the 944T oil cooler.

Performance Options
Lightened, balanced, and cross-drilled crankshaft, and upgraded camshafts profiles are optional.

With the options the total cost was ~$13,000. Without the options above, and other options not mentioned the total cost would have been ~$10,000.

The cost does not include fuel mangement components, and custom turbo.

Fuel Managment
I used the 944T fuel managment to start-up and break in the engine. After that I intend to use an aftermarket fuel management system to tune the car.

devgriff

See pictures of engine and clutch assembly attached

devgriff

This is the almost finished product

Tom M'Guinn

What 944T fuel management are you referring to -- must be something more than stock DME, no?

How does that clutch combo feel?

jgporsche

[QUOTE=devgriff] With the options the total cost was ~$13,000. Without the options above, and other options not mentioned the total cost would have been ~$10,000.
[QUOTE]


That's not a bad price, considering you can spend $4000-$4500 alone in purchasing the motor and clutch.

ibkevin

Did you do anything similar to the ceramic coating on the head exhaust ports?

DDP

That is also what I'm wondering. What about exhaust valves? 944T have sodium filled.

AL951

What type of belt did you use with the cams set up?........Is the engine running as of now?

Regards,
AL

fortysixandtwo

I guess I'll do a quick over view of mine.

Edit: (03/12/07)
I don't really feel like shareing this information anymore.

The engine is being built by and will be tuned by Scott Gomes at Under Pressure Performance

Chris White

Ok, I’ll toss out some info – on two motors in progress

3.1 16v – (street engine – occasional DE use)
Based on a S2 block with Darton MID sleeves bored to 106mm, JE pistons (skirt ‘lube’ and top heat coatings). Block has been modified with piston oil squirters.
Additional oil cooling
Mildly knife edged crank (just leading edges cleaned up). Stock forged rods.
Head – S2 head with custom cams (both based on exhaust cams). Chain eliminated and dual adjustable cam gears (this requires a custom crank drive gear).
Custom intake manifold (this is the part in progress) to use a Carbon Fiber plenum, welded alum runners and the stock S2 flange.
SFR stage 1 exhaust (with EGT provisions)
GT35R turbo with SFR plumbing/flanges
Tial 46mm ‘gate
951 based alum flywheel, Blaszak clutch
Tec3 management

2.6 16v – (race engine)
Based on a S2 block with Darton MID sleeves bored to 101.6mm, JE pistons (skirt ‘lube’ and top heat coatings). Block has been modified with piston oil squirters.
Knife edged cross drilled crank. Pauter rods.
Dry Sump (5 stage) system.
Head – S2 head with custom cams (both based on exhaust cams). Chain eliminated and dual adjustable cam gears (this requires a custom crank drive gear).
Custom Intercooler (very large)
Custom intake manifold (this is the part in progress) to use a Carbon Fiber plenum, single throttle per cylinder, welded alum runners and the stock S2 flange.
SFR stage 2 exhaust (with EGT provisions)
GT30R turbo with SFR plumbing/flanges
Tial 46mm ‘gate
951 based alum flywheel, Blaszak clutch
Tec3 management

That about covers it. The current plan (as long as I get some time to play with my own projects) is to run both engines on the engine dyno late winter. Best place for tuning the system – the S2 cams are not intended for turbo charging so I have worked up some custom cams that will need some playing around’ with to establish proper cam timing and intake to exhaust separation.

BTW – putting turbo engines on an engine dyno is a pain in the but!

Chris White

300guy

Chris,

some good info there. I have a couple of questions... these questions are intended for educational purposes... I am NOT questioning your ability or what you did. I just want to learn thats all.

When you say stock forged rods... are you talking about S2 951 or 968 rods?

And on the 'street engine" why is it only a "Mildly knife edged crank "and no cross drilling, but on the 'race engine' its knife edged cross drilled. Could you explain your reasoning on this please?

Also, do you think that its necessary to have oil squirters as well as the heat coatings on the pistons?

Did you get a coating put on the valve/cumbustion chamber?

Where do you get the cam gears/crank gear?

Colin

devgriff

The clutch combo feels very good. The clutch pedal is not as stiff as I had expected.

The fuel management system I am using to break-in the engine is MAF calibrated for Bosch 52lb injectors.

I did not ceramic coat the head because I knew of two 3.0L 16v turbo in use for several years without any heat related problem eventhough the head was not ceramic coated. Furthermore, there is a possibility that the ceramic coating can break off in large fragments and cause damage to the turbo.

Chris White

Hey, I do all my own work with just a pair of vice-grips and a hammer!

951 forged rods. S2 rods are cast and 968 rods do not have a great reputation.

Two issues – ‘serious’ knife edgeing - grinding off a lot of material – will take away some of the torsional vibration dampening of the crank – making it more susceptible to long term fatigue. I wouldn’t want that in a street crank but for a race engine that gets minimal hours and a lot of inspection its OK. Also – if the rotating internals are too light it makes for a difficult to drive street engine.
The cross drilling is not needed in a street DE engine and possibly not needed for a dry sump motor – but I was having the crank worked so why not? The down sides of cross drilling have been covered by the dry sump system.

Necessary….I don’t really know, I haven’t doen any testing on the system - call it a little extra insurance. Besides – it helps with wrist pin oiling – remember that a dry sump system will have a lot less oil flying around!

I will do that before the final fit up. I have seen some very high EGTs in the 8v set up so the extra insurance is worth it. I will also have the exhaust ports coated.

Some secrets here…but what the hell – how many people could possibly read this
The cam gears are from a Honda engine (aftermarket). The snouts of the cam gears (both cams have to be exhaust cams) are machined down to match the Honda dimensions. The drive gear on the crank shaft is a custom made part.

The reason for the Honda gears is that the stock Porsche gear is too big to fit side by side. The Honda gears are smaller OD (and have less teeth).

Chris White

Chris White

I should add that since I use the Tec3 I don’t need a distributor – so I can alter the cam gears easier!!

Chris White