Quote:
Originally Posted by ike84
I don't think it's a good idea to put 3.2 heads on a 3.8 case. The vales are going to be way undersized, even with a high lift cam. When Porsche redid the 3.4 for the x51 package one of the things they did was increase valve size significantly (I wanna say over to% but that's off the top of my head).
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First off I read that the 3.2 and 3.4 5 chain heads have the same valve size. Difference between the two is the 3.2 has a smaller combustion chamber. So, I’ll be using valves sized for 3.4 with 3.8. A stretch, but not ludicrous. Engine design is trade offs, like you say. Bigger valves give higher ultimate horsepower but you sacrifice low end torque. Smaller valves enhance low end, but sacrifice high end horsepower. I want my engine to pull more low and middle, and if I lose some bragging rights on the high rpm end I’m ok with that. I decided the cams were too much craziness, stock 3.4/3.2 cams will do fine.
Quote:
Originally Posted by ike84
Unless you have a tuner who truly knows me 7.2 and the tools to do it right (which if you do please share because I'm not sure there is anyone in the US that really does) then the setup will never be optimal.
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I contacted a bunch of tuners, and explained what I was doing and most of them said they had no idea.Softronic, however, said they could tune for it no problem. Not sure if they are making claims they can’t back up? Anyone that has any input there I would appreciate it.
Quote:
Originally Posted by ike84
If it were me and I were going through this trouble, id do the least I had to in order to get that engine running properly, then sell it and buy an Audi abz or a 2.7T and do a swap that will put out 400hp. Please rember that in any configuration other than stock, even if it is all genuine Porsche products, you're extremely unlikely to ever see your money back from modifications like this when you go to sell it.
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This gets into more of a philosophical question. Would you take the vintage jaguar with the V 12 and all its problems, or with the LS swap? See, I would take the V 12. Other people would take the LS. Neither way of doing it is better, they’re just sort of different philosophies. When I’m sitting at the starting line at autocross and I’m about to put my foot in it, do I want to hear the roar of a V-8 or the scream of the flat six. I want the flat six. Other people rightfully so would say that the expense of getting an M96 engine which is not too arguably a piece of junk to do this reliably is not worth it. I like building engines, I’ve done several and had a lot of fun doing it. There’s something about putting your foot into it with an engine you built that is very satisfying.
So I guess what I’m saying is, I’m building the 3.2 to 3.8 because I want to not necessarily because I’m expecting it to have the most power per dollar. I’m pretty sure it won’t. To some degree I’m doing it because my car is worthless with a non-running motor. I tried to sell my transmission for the cost of machine work so basically you’re getting the transmission and the Quaife differential for free and no one was even remotely interested. I’m assuming any money I’ve put into the car so far is sunk, I’ll never get it back. I’m figuring, assuming my roller has minimal value, if I build a good engine and sort everything I can get the going rate for a decent S, not even a high value one, and break even. That’s good enough for me.
Off to LN tomorrow, I’ll take some pix if they’ll let me.
Regards,
Silber