Porsche 944 turbo road to racecar.

[333pg333]

Bored at work. Thought I'd do an update for 2016.

New motor is coming together. It's actually a years old project that got covered in dust while dealing with other motors but eventually or finally I decided to finish it. Finally also, a twin cam 16v motor too!! Should provide a significant improvement over the previous 8v motors.

Due to the lack of torque and increase of lag with the last 2.5 8v motor we decided to do a stroker crank on this latest one. The stock 3ltr crank is 88mm and we've moved out to 94mm. Quite a jump but not outrageous. Combined with a 104.75mm piston we have about 3.2ltr capacity. The combo of crank and cc increase should get us some of the much missed torque from the old 3.1 8v motor with the added advantage of more headroom in the upper rpms with the worked 16v head.

It was decided rather than sleeve the block we had it Nikasil coated to retain greater original block structure and also reduced friction with the almost mirror coating. Custom CP pistons and Carrillo rods have been designed and built accordingly. The open deck block has been strengthened via a custom deckplate and the larger bore headstuds also have additional certs to allow higher torque loads when clamping it down.

While the head has been modified I don't have the flow ratings to hand. The stock 968 head actually flows approx 340cfm which is pretty decent as is. I think this one will flow more like 400cfm. We're not going with monster cam profiles as we want to retain a bit more tq lower down in the rpm range. The stock Vario cam setup has been removed and new twin cam pulleys have been made to run a front drive system with an extra pulley to pinch the belt in more at the crank pulley. We're also discussing getting a custom Damper made up by ATI to suit and then remove the balance shafts.

Once we resumed finishing this motor it was my intention to switch to an EFR turbo. I went through a bit of back and forth emailing with the owner / engineer of Full Race turbos in the US. It was going to involve a whole new system of 4 - 2 headers and twin X overs plus a new turbo back exhaust system too. That whole exercise was going to cost circa $10k and take more time. So I listened to good advice given by Paul and we will just put the motor into the car we have now and see what we get. If we need to make changes we can do it along the year.

Going to switch to an electric water pump also. Damn there's a ton of choice through Davies-Craig.
http://daviescraig.com.au/electric-water-pumps

Block is finished. Just waiting on cams to be ground and the cam drive system to be checked. Hopeful to have it down here before end of Feb.

[Guido]

Great to see.

[CT]

Go alloy body with the davies craig - very important!! I had one of the first ones they made and tested it. The plastic ones are great but under extreme heat (racing) they can deform slightly and leak from the o-ring seals. They are good guys though and their product development guys listened to us hence the alloy one!

[333pg333]

Thanks. Was advised the same by someone else too. I might contact them to see if they can offer any theory or practical knowledge in regards to bringing a 2nd line into the rear of the head which gets hotter.

[profi]

Ford nascar engine runs twin thermostat's, one for each head as they run at different temps

[333pg333]

Interesting. We only have the one head to worry about but still not sure re introducing a second water inlet to the head.

[333pg333]

Been quite a long time between posts on the 16v motor. There have been a few design changes and part delays along the way also.

Block has been Nikasil treated for extra hardness. The main studs holes have been additionally strengthened by a version of a Time Sert. With the extra torque loading on these 25yr old blocks and larger headstuds it was deemed a worthwhile modification. We did something similar down here with the 2.5 8v racemotor.

Certain parts such as bearings and rings have been coated with an anti friction coating used by Honda in F1. Ultimately we would like to use a custom crank but at this stage it is a stock crank with some lightening (approx 6 lbs I think) and has been modified to a 94mm offset grind to enhance torque. The main issue we have with our car is the stock Syncromesh 6 speed vs competitors with Sequential Transmissions which are a massive improvement. So we need to maximise torque to give us a lot of drive off the corners and possibly reduce the amount of gear changes. The old 3.1 8v had about 720Nm of tq to the rear wheels which is a lot. Hopefully the 16v motor can give us something similar.

The cams are being ground now and they've been designed more around mid range than totally upper rpm. The valve train will be capable of spinning out to well over 9000rpm but we'll not get up that high. Not quite sure where we'll set the rpm cut. Perhaps around about 8000rpm and a soft cut rather than the hard cut we've been running on the previous motors. Just a bit more friendly to the components. The head was flowed to a max of 370cfm at 25". It was decided to not go overboard on the exhaust side to try and induce more rapid response both on and off boost. Potentially the superior head and 3.2 capacity should ensure that we can reach similar power (say 550whp) at lower boost than before therefore enhancing reliability. It will be running adjustable twin cam wheels at the front of the motor with a modified tensioner to increase belt wrap on the custom crank pulley.

There will be a custom ATI damper to quell harmonics but also incorporate a pulley to run the alt belt off. The idea is to shorten the parts hanging off the nose of the crank to further reduce the possibility of crank distortion which we felt was the likely reason for the failure of the 3.1 motor. The balance shafts have been removed. We felt that the main purpose for the balance shafts is to deal with harmonics in the lower to mid range. In addition, they were designed and built with the stock motor all those years ago. With every single part in the new motor changing in weight, size, balance etc it was felt that they were almost redundant.

The head will be sealed via a custom Cometic gasket designed to run with custom Garlock sealing rings. Due to some changes in their company structure these Garlocks have taken many months to procure. Hopefully they do the trick combined with the possible lower boost needed.

I went down the path of changing to a Borg Warner twin scroll EFR turbo. I would really like to change to one of these, however budget is tight and this would have added about $10k to the build with changes to the headers, X overs, turbo and I would have also changed the exhaust to a larger than 3" straight through system. So reluctantly we decided to keep all the externals that we have and at least we can compare this motor to the 2 previous ones apples to apples as such. We will move up to the largest turbine housing for the GTX3582r and therefore our setup will be quite similar to a mate's motor which achieved very good figures on the dyno. I'm not expecting quite the same figures on the basis of expected pessimism but even 80% of what he got will be very pleasing. The main difference will probably be the length of inlet runners. His are quite a bit shorter. Due to budget and also packaging constraints I have decided that we will probably just modify the intake we have now. Enhancing the tq with the longer runners won't be such a bad thing.

The rods are custom design Carillo and pistons are short skirt CP. Obviously considerably lighter than stock.

The stock water pump is being blocked off and we will be using a Davies-Craig electric product.

The block and head will be sent down to us within the next 10 days. We can start working on fitting the motor and rejigging the headers and inlet. Also fit the water pump. The cams and drive pulleys plus tensioner will follow shortly afterwards. Hopefully not too long to get this motor in the car and tuned.

[nuk1ear]

good news and look forward to the updates. Always loved this car, showing up with 8 valves and giving evos a big scare. Its awesome

[333pg333]

Thanks. Can't wait for the remaining 8 valves to appear! The builder is doing a lot of custom work on this motor. Really should have started with a different platform or even motor. Really hoping this one will be the last!

[brypar]

Great to hear the new PowerTrain is coming together and be here soon Pat. Will pop in to cast my eyes over it. Impressed

[nuk1ear]

Thanks. Can't wait for the remaining 8 valves to appear! The builder is doing a lot of custom work on this motor. Really should have started with a different platform or even motor. Really hoping this one will be the last!

No need for another boring evo at time attack. Well, all of the fast ones are not really Evos anymore anyways. I like unique things like this. Very cool stuff indeed!

[333pg333]

Great to hear the new PowerTrain is coming together and be here soon Pat. Will pop in to cast my eyes over it. Impressed

Man all I keep reading is "We've had to make new part X to fit the custom part Y. Not long now". All I keep hearing is Cha-Ching!

No need for another boring evo at time attack. Well, all of the fast ones are not really Evos anymore anyways. I like unique things like this. Very cool stuff indeed!

Thanks Nuke. I do appreciate it. It's been a looooooong haul and many times I've lamented not going with a much easier platform. Sure, it's a bit different but that tends to cost a lot extra time and $$ for that uniqueness. T'is the rod I bear lol...

[I'm DJ!]

So cool Pat, can't wait to see the twin cam in there!

[333pg333]

You and me both!

[turbosurfer]

Nul1ear no disrespect intended to 333pg333 I really enjoy what hes doing but this 944
aint a standard 944 either.