Vedänpä kylmästi copy pastella täältä http://www.saabcentral.com/forums/viewtopic.php?t=24154
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All of this talk about our GM EcoTec based engines coming apart at 260hp forced me to do a little research. It would seem that GM has really done their homework with regards to engineering and developing these engines. Below is summary of what has been done to a base 140hp EcoTec:
A base 140hp normally aspirated EcoTec can be pushed to 280hp before the connecting rods give up at which point GM upgrades the rods, pistons, wrist pins and rings. Keep in mind that SAAB uses their own “upgraded” internals so presumably our engines are good for a bit more before the rods die.
The next stop is at 350hp when the head bolts are enlarged to 7/16 to keep the head gasket from leaking. SAAB is using their own head and I don’t know the head bolt size. With the larger head bolts the stock gasket is good for 650hp.
At 400hp they upgrade the valves. Again these are upgraded from the stock valves used on a normally aspirated EcoTec and not the valves that SAAB uses in their own head.
At 500hp the stock crank is upgraded and the head studs are again upgraded. As mentioned earlier this is upgraded from the stock 140hp EcoTec.
It isn’t until 650hp that the head needs a major reinforcement. What is more amazing is that it engine block makes it to 750hp before the sleeves need to be addressed.
All of this leads me to believe that the tuner who was blowing up engines at 260hp wasn’t doing their homework. Speaking of homework… GM publishes the “EcoTec Engine Handbook” (PN 88958646) available from your local GM dealer for anybody interested in how to hod rod your EcoTec based engine. Perhaps we should send a copy to the engine builder who says that there isn’t anymore horsepower to be had in these engines.
Below are some of the links that I used for my research.
http://www.year2032.com/ecotec.htm
http://www.saturnfans.com/Cars/Powertra ... ades.shtml
http://www.saturnfans.com/Cars/Motorspo ... otec.shtml
http://media.gm.com/events/sema/sema03g ... linder.htm
Next research task is to find out what other cars are using our poor cold shifting 6-speed transmission and if they are having the same problem.
Enjoy,
Ron Johnson
2004 Aero