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S4 & S5 engines compared?

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Old 02-28-03, 05:23 PM
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S4 & S5 engines compared?

Sorry...I tried searching for these differences. I was wondering, what are the benefits(like why more/less psi or compression etc.) to having either the S4 engine or the S5 engine? Also if they would have any negative sides too. Thanks.
Old 02-28-03, 07:13 PM
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S5 has bigger ports, better turbo, better manifolds, higher compression. Kind of sad the s5 motor only makes 20bhp more than a s4.

Last edited by dr0x; 02-28-03 at 07:28 PM.
Old 02-28-03, 07:22 PM
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Originally posted by dr0x
NA or turbo?

S5 has weaker/lighter internals, allowing for the higher revs. S4 has heavier/stronger internals. S5 has bigger ports, better turbo. I believe all turbo ii motors had a 8.5:1 CR and NA had 9.0:1. Kind of sad the s5 motor only makes 20bhp more than a s4.
Internals were not weaker in S5's!

S4 NA: 9.4:1 CR
S4 TII: 8.5:1 CR

S5 NA: 9.7:1 CR
S5 TII: 9.0:1 CR
Old 02-28-03, 07:25 PM
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Was the sidewall on the not thinner on the s5? And wow, NA's have more compression than I thought.
Old 02-28-03, 07:25 PM
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Also, the irons's had more meat on them in the S5's, allowing for larger porting, and extra meat around the dowel pin area, which was prone to crack on S4 Turbo engines.

The rotor housing coating procedure became changed drastically. The S5 housings last A LOT longer before showing flaking of the chrome surface.

The EGR was removed from all S5 engines, and the port air induction into the block was changed.

There are a few more, but those are the major ones.

Power:
S4 NA: 146 hp
S5 NA: 160 hp

S4 TII: 182 hp
S5 TII: 200 hp
Old 02-28-03, 07:26 PM
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Originally posted by dr0x
Was the sidewall on the not thinner on the s5? And wow, NA's have more compression than I thought.
sidewall? be more specific. The rotor housings were not any thinner, and the irons were thicker.

Sidewall refers to tires.
Old 02-28-03, 08:03 PM
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Originally posted by scathcart
sidewall? be more specific. The rotor housings were not any thinner, and the irons were thicker.

Sidewall refers to tires.

My guess is that he's referring to the strength of the rotors themselves, the S5's are lighter but as a result cannot handle as high of combustion chamber pressures. I think it was crispeed that said he ran S4 rotors because they can take more boost?
Old 02-28-03, 09:50 PM
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what about streetported s4 or s5 engine? or is there such a thing?
Old 03-01-03, 01:19 AM
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the S5's are lighter but as a result cannot handle as high of combustion chamber pressures.
THey may be 1lb lighter, but theyre made just as well. I dont know where this came from. An s4 rotor is just as seceptible do damage as an s5.

The reason (in a turbo application) to run s4 rotors is lower compression ratio; this favors higher boost for more safety. I have heard that some tuners in japan etc. prefer to use s4 t2 rotors in high power FD's etc. due to extra safety margins(s4 t2 rotors are lowest compression of all).
Old 03-01-03, 01:31 AM
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Originally posted by pengarufoo
My guess is that he's referring to the strength of the rotors themselves, the S5's are lighter but as a result cannot handle as high of combustion chamber pressures. I think it was crispeed that said he ran S4 rotors because they can take more boost?
They can handle more boost due to a lower compression ratio, not b/c of strength.
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