I did some searching and found that the s5 na block has 1/2 lbs lighter rotors and slightly higher compression than the s4 na. My question is, with the same carb setup that was on my s4 being put on the s5 block give a noticible difference in power? Will I lose torque at all from not having the heavier rotors? Or is there no in the seat difference at all? higher redline? quicker acceleration? I know that most the power on the s5 was from the difference in intake manifold runners (VDI) but I like my Mikuni carb and will just be swapping it on.
Thanks guys

 

well, you'll get a higher redline and *may* have (or want) to adjust the jetting in your carb after the swap.

I would say you can expect more from the S5, even without the VDI, simply due to the higher compression and lighter rotating assembly. But I dunno how much.

 

well I just found out that the motor was in a car with an auto tran. so now I need a s5 flywheel, the s4 flywheel is the wrong wieght and will ruin the bearings. Do I also need a counterweight?

 

No, the S5 flywheel has its counterweight casted into it.

The flexplate you'll be taking off will have a removable counter weight which you can use with a lightweight flywheel (aftermarket) but the stock flyhweel has it already attached.

 

alright so the front weight doesnt have to be changed I just have to either get a stock s5 flywheel or a light flywheel that would require the weight from the auto flexplate thanks alot for your help. now to find a flywheel for cheap

 

Can I use my s4 clutch on the s5 flywheel?