dohc. ONE pully Options

[freakyre33c]

the 5sfe have dohc but one cam is driven by the belt, and that cam drives the other cam, why is it set up like this , why not just two pullys ? what are advantages and disadvantages?

[alltracman78]

It depends what you are trying to do......................................................
The 5SFE wasn't designed for high rpms.
It was designed for low rpm power. In which that particular setup works quite well..................
The narrow design hurts high rpm performance, weather it's NA or FI.
Look at Mannys 5SFTE. Wonder why he's making more torque? At lower rpms?.

[Kwanza26]

It depends what you are trying to do......................................................
The 5SFE wasn't designed for high rpms.
It was designed for low rpm power. In which that particular setup works quite well..................
The narrow design hurts high rpm performance, weather it's NA or FI.
Look at Mannys 5SFTE. Wonder why he's making more torque? At lower rpms?.

I don't think you understand what I'm saying. There's no way to make additional n/a power (not talking about making stockish power here) in a 4 cylinder without revving the engine... PERIOD... regardless of the head. Case in point... how many 1.6 to 2.0 liter 4 bangers do you see making 200hp n/a with a 6200 rpm redline? None.

In the case of the 5SFE... it can't rev because the head doesn't breathe well at higher rpms (makes it redundant to rev) nor does the stroke ratio like being revved (stress peaks = torque loss)... true enough... but forced induction changes the game. The power potential isn't so much limited by the head with forced induction, as it is limited by how much you boost (the set-up). The only thing the FE head affects strongly, is where that power is located... but the more torque you have, the less you have to worry about "where" power comes it the strongest. To further elaborate this point... think gearing.

FE head = bad n/a platform... great F/I Platform... excellent daily driver
GE head = great n/a platform... great F/I platform... ehh daily driver (TVIS/ACIS for the daily driver)

[alltracman78]

It depends what you are trying to do......................................................
The 5SFE wasn't designed for high rpms.
It was designed for low rpm power. In which that particular setup works quite well..................
The narrow design hurts high rpm performance, weather it's NA or FI.
Look at Mannys 5SFTE. Wonder why he's making more torque? At lower rpms?.

I don't think you understand what I'm saying. There's no way to make additional n/a power (not talking about making stockish power here) in a 4 cylinder without revving the engine... PERIOD... regardless of the head. Case in point... how many 1.6 to 2.0 liter 4 bangers do you see making 200hp n/a with a 6200 rpm redline? None.

In the case of the 5SFE... it can't rev because the head doesn't breathe well at higher rpms (makes it redundant to rev) nor does the stroke ratio like being revved (stress peaks = torque loss)... true enough... but forced induction changes the game. The power potential isn't so much limited by the head with forced induction, as it is limited by how much you boost (the set-up). The only thing the FE head affects strongly, is where that power is located... but the more torque you have, the less you have to worry about "where" power comes it the strongest. To further elaborate this point... think gearing.

FE head = bad n/a platform... great F/I Platform... excellent daily driver
GE head = great n/a platform... great F/I platform... ehh daily driver (TVIS/ACIS for the daily driver)

I understand EXACTLY what you are saying.
My point is, it's not just NA. If you throw a turbo on there, you have the EXACT same problem. It won't make the same hp as a G head, all mods being relative. It will make more torque.
You can bump the torque a bit, granted not as much as you can raise the hp with higher rpms.
But the point of the F head is to make power at low rpms. FI or not.

I agree it's not a good NA platform, but the same power blocks are there if you go FI [relative of course].