Anyone built a 2,5l 16 valve turbo?
10-10-2003, 10:01 AM
#2
Gustaf,
i suppose it can be done. You have to modify head to accept 944 blocks water passage.I suppose Vario Cam is out of question.You also have to modify your intake & exhaust.But with some SEK ($$) it is possible.
i suppose it can be done. You have to modify head to accept 944 blocks water passage.I suppose Vario Cam is out of question.You also have to modify your intake & exhaust.But with some SEK ($$) it is possible.
10-10-2003, 10:17 AM
#3
Rennlist Member
Duke, there will be no advantge in using a 968 head if you cannot use variocam (ofcourse besides more airflow). Also variocam has its own issues with failures and chain stretch so I would suggest, stay away from it.
You are better off using an S2 head, especially for turbocharging. It also has its issues with chain tensioner but if you change the rails, you should be ok.
Variocam requires a pulse from the DME to activate and deactivate and only way to do this is to either get a standalone that can provide you with the triggers or use 968 DME, which is not good either as it does not have KLR for boost control.
Speaking to a custom chip builder, I found out that the stock 968 DME chip setup is not the best for turbocharging as the maps do not allow for the broader range of adjustability required for turbocharging. Standalone would be your best bet to make it happen.
You are better off using an S2 head, especially for turbocharging. It also has its issues with chain tensioner but if you change the rails, you should be ok.
Variocam requires a pulse from the DME to activate and deactivate and only way to do this is to either get a standalone that can provide you with the triggers or use 968 DME, which is not good either as it does not have KLR for boost control.
Speaking to a custom chip builder, I found out that the stock 968 DME chip setup is not the best for turbocharging as the maps do not allow for the broader range of adjustability required for turbocharging. Standalone would be your best bet to make it happen.
10-10-2003, 11:30 AM
#4
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I am in the process of building one for my track car. I believe this setup will be nice for a high flow / high rpm engine but the bottom end will be a bit weak. Keep in mind that there are tradeoffs.
The 8 valve head is a great setup for a street car because its smaller port area results in higher port velocities at low rpms which results in better torque and low end response. There are a number of folks on this list who are producing 350 to 400 hp at the rear wheels with a 2.5 liter engine running an 8 valve head!! That is a fantastic combo for a street car -> big power with big torque.
I would recommend only considering going to the 16 valve head if you want to give up some bottom end performance to gain the ability to spin the engine faster than 6,500 rpm and potentially produce more than 400 hp to the rear wheels. Although the small displacement 16 valve engine would not be a very good all around street engine, it sure should be nice for a track car!! One other thing -> I am not using the variocam setup for my project.
Now . . . a 3 liter, 16 valve head, turbo engine would be a very nice street engine!! The additional 0.5 liters of displacement is just enough to generate the additional exhaust energy to give you your bottom end torque back AND also provide big hp up top.
Jeff
The 8 valve head is a great setup for a street car because its smaller port area results in higher port velocities at low rpms which results in better torque and low end response. There are a number of folks on this list who are producing 350 to 400 hp at the rear wheels with a 2.5 liter engine running an 8 valve head!! That is a fantastic combo for a street car -> big power with big torque.
I would recommend only considering going to the 16 valve head if you want to give up some bottom end performance to gain the ability to spin the engine faster than 6,500 rpm and potentially produce more than 400 hp to the rear wheels. Although the small displacement 16 valve engine would not be a very good all around street engine, it sure should be nice for a track car!! One other thing -> I am not using the variocam setup for my project.
Now . . . a 3 liter, 16 valve head, turbo engine would be a very nice street engine!! The additional 0.5 liters of displacement is just enough to generate the additional exhaust energy to give you your bottom end torque back AND also provide big hp up top.
Jeff
