3.8 Engine rebuild
#91
Drifting
Thread Starter
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I have a question about 964 cylinder heads. As I understand it the real performance gains from bigger valves is down to exhaust ports... although presumably this would ruin the ceramic lining?
I read that Cup cylinder heads are around £3,500?! What are the options regarding cylinder heads and prices?
Thanks in advance.
Cheers,
I read that Cup cylinder heads are around £3,500?! What are the options regarding cylinder heads and prices?
Thanks in advance.
Cheers,
#92
Burning Brakes
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I have a question about 964 cylinder heads. As I understand it the real performance gains from bigger valves is down to exhaust ports... although presumably this would ruin the ceramic lining?
I read that Cup cylinder heads are around £3,500?! What are the options regarding cylinder heads and prices?
Thanks in advance.
Cheers,
I read that Cup cylinder heads are around £3,500?! What are the options regarding cylinder heads and prices?
Thanks in advance.
Cheers,
When I was having my engine built I was advised that the 964 had superior port angles to the 993 (and that's before you start opening them out), hence why my engine is 993 bottom/964 top.....
of course there's the 9Meister heads which according to Geoffrey have a design which is much improved over the original factory design...…
but don't forget that any gain from the head could be lost or reduced by other compromises in the build, so make sure your chosen engine builder is viewing the build holistically rather than "selling you" the benefits of one area of improvement....
#93
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Hello Grant,
With a compression ratio of ~12:1, if not more, it's better to be safe than sorry. The engine builder races cars with the same engine in Dakar and the additional oil cooler reduces the oil temperature by up to 20C. If I'm not mistaken it can be ordered from FVD - part number FVD 207 035 00. Fach Auto Tech may have used two for 3.8l Cup cars if I have understood things correctly... When sitting in a traffic jam on the motorway at 30C+ outside temperature, the oil temperature rarely exceeds the half way mark...
Cheers, Mark
With a compression ratio of ~12:1, if not more, it's better to be safe than sorry. The engine builder races cars with the same engine in Dakar and the additional oil cooler reduces the oil temperature by up to 20C. If I'm not mistaken it can be ordered from FVD - part number FVD 207 035 00. Fach Auto Tech may have used two for 3.8l Cup cars if I have understood things correctly... When sitting in a traffic jam on the motorway at 30C+ outside temperature, the oil temperature rarely exceeds the half way mark...
Cheers, Mark
#94
Burning Brakes
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Hello Grant,
With a compression ratio of ~12:1, if not more, it's better to be safe than sorry. The engine builder races cars with the same engine in Dakar and the additional oil cooler reduces the oil temperature by up to 20C. If I'm not mistaken it can be ordered from FVD - part number FVD 207 035 00. Fach Auto Tech may have used two for 3.8l Cup cars if I have understood things correctly... When sitting in a traffic jam on the motorway at 30C+ outside temperature, the oil temperature rarely exceeds the half way mark...
Cheers, Mark
With a compression ratio of ~12:1, if not more, it's better to be safe than sorry. The engine builder races cars with the same engine in Dakar and the additional oil cooler reduces the oil temperature by up to 20C. If I'm not mistaken it can be ordered from FVD - part number FVD 207 035 00. Fach Auto Tech may have used two for 3.8l Cup cars if I have understood things correctly... When sitting in a traffic jam on the motorway at 30C+ outside temperature, the oil temperature rarely exceeds the half way mark...
Cheers, Mark
Thanks for the reply. I can understand additional oil cooling on a race engine, especially in the Dakar, but I tracked my car at the Bahrain F1 track many times and even then, in 40+ ambient, I rarely saw the temp rise into the red.
However, as you say better to be safe than sorry I suppose.
Maybe this gives Frank more food-for-thought!
#95
Drifting
Thread Starter
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- enlarge the throttle body;
- drop in Wössner 3.8l PC kit with ~12.1 compression, i.e. no machining of the crankcase;
- wide Carrillo RSR conrods;
- ARP headstud kit;
- ARP case through bolt kit;
- Schrick titanium valve retainers;
- Eibach valve springs;
- new valve guides and valves;
- boat tailing of the crank case;
- suffle pinning of the crank case;
- welding of additional aluminum material on the cylinder heads à la 964/993 Cup;
- ADDITIONAL OIL COOLER;
- replacement of the old oil cooler as well as all oil lines;
- 993 3.8 RS fuel injectors, as well as
- lots of other items I cannot think of right now.
Am I happy with the result - yes, definitely.
Would I do anything different - yes, consider installing 993 Cup cylinder heads with the 8mm valves while the engine is apart...
What valves are you running?
Hi Frank
When I was having my engine built I was advised that the 964 had superior port angles to the 993 (and that's before you start opening them out), hence why my engine is 993 bottom/964 top.....
of course there's the 9Meister heads which according to Geoffrey have a design which is much improved over the original factory design...…
When I was having my engine built I was advised that the 964 had superior port angles to the 993 (and that's before you start opening them out), hence why my engine is 993 bottom/964 top.....
of course there's the 9Meister heads which according to Geoffrey have a design which is much improved over the original factory design...…
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
#96
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Before I forget Cartronic Motorsport in Germany modify original 964 and 993 cylinder heads whereby the flow is apparently 7.5% better than the RSR cylinder heads - www.cartronic-motorsport.de. After reading an excellent article about a black 1973 Carrera 2.7 in the Excellence magazine last year whereby the engine had been optimised with original Porsche parts I would honestly prefer to install RSR heads if money were not an object... At the same time I realise that technology has moved on and there are better solutions out there. In a decade or so it would, however and IMHO, be nice to see an article about a narrow body 964 C4 with a RSR spec engine that had been tastefully optimised over the years...
#97
Drifting
Thread Starter
#98
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Hello Frank,
It's probably best to give Marc De Siebenthal a call regarding HP figures - I was focused on torque and am very happy indeed. If I'm not mistaken torque levels should be comparable with the 3.6l turbo.
Regarding the valve sizes, they are stock - bigger is not always better...
Cheers,
Mark
It's probably best to give Marc De Siebenthal a call regarding HP figures - I was focused on torque and am very happy indeed. If I'm not mistaken torque levels should be comparable with the 3.6l turbo.
Regarding the valve sizes, they are stock - bigger is not always better...
Cheers,
Mark
#99
Burning Brakes
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Hello Frank,
It's probably best to give Marc De Siebenthal a call regarding HP figures - I was focused on torque and am very happy indeed. If I'm not mistaken torque levels should be comparable with the 3.6l turbo.
Regarding the valve sizes, they are stock - bigger is not always better...
Cheers,
Mark
It's probably best to give Marc De Siebenthal a call regarding HP figures - I was focused on torque and am very happy indeed. If I'm not mistaken torque levels should be comparable with the 3.6l turbo.
Regarding the valve sizes, they are stock - bigger is not always better...
Cheers,
Mark
My 3.6 puts out 418Nm @4800rpm, which is still behind the 3.3l turbo (450Nm @ 4500rpm)
#100
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Hi Frank,
Regarding Cartronic and the flow levels, I honestly do not know whether 7.5% applies to the intake and exhaust. I obtained this information from their website. Last year I saw a 993 3.8l motorsport kit from Porsche on sale in eBay in the US and I recall seeing reference to Cartronic on the ECU... I guess it's a small world out there...
Cheers,
Mark
Regarding Cartronic and the flow levels, I honestly do not know whether 7.5% applies to the intake and exhaust. I obtained this information from their website. Last year I saw a 993 3.8l motorsport kit from Porsche on sale in eBay in the US and I recall seeing reference to Cartronic on the ECU... I guess it's a small world out there...
Cheers,
Mark
#101
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Hi Grant,
Boat tailing and the compression ratio probably explain a lot... I'll ask Mecacomponents for the power and torque chart and will post it. Piston skirts are also mooned...
Cheers,
Mark
Boat tailing and the compression ratio probably explain a lot... I'll ask Mecacomponents for the power and torque chart and will post it. Piston skirts are also mooned...
Cheers,
Mark
#102
Drifting
Thread Starter
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Thanks Mark.
#103
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#104
Burning Brakes
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Your car is clearly the Standard for all 964 rebuilds on here, and you've done a great job at documenting it. From what I can see, unless you made updates that I missed, you are using the stock crank and oil pump and running above 7,000 rpm. Just curious to hear your reasoning behind this, and any issues that might have come up.
Thanks
Thanks
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#105
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Your car is clearly the Standard for all 964 rebuilds on here, and you've done a great job at documenting it. From what I can see, unless you made updates that I missed, you are using the stock crank and oil pump and running above 7,000 rpm. Just curious to hear your reasoning behind this, and any issues that might have come up.
Thanks![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Thanks
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
Crank - cost. Stuck to original that was balanced etc.
Oil pump - not an all out race car in desert temperatures, requires case machining too.
Forged connecting rods allowed for the high rpm amongst other bits of the puzzles. Why? HP and torque. Next is the flat slides and GT3 plenum with uprated injectors as the engine was designed for this intake system - which will result in more midrange torque and few more hps. Engine has been flawless, just the mushy bit behind the wheel needs improvement.
![Smilie](https://rennlist.com/forums/images/smilies/smile.gif)
But all of this is covered in the actual build thread - this was just my research thread.
Build thread here: https://rennlist.com/forums/964-foru...e-rebuild.html
Pls click on the 'Molested' link in my sig for all info and thanks again for the kind words.
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