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How to build s4 block to handle 400hp

Old 10-29-17, 02:14 AM
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How to build s4 block to handle 400hp

So ive taken my fc for a tune and the rear plate cracked at 315hp so ive got a s5 rear end plate and have to get it skimmed and re-hardend. I will get it put back together but will that alone support 400hp or close to it? I dont want dowel etc if i dont have to
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Old 10-29-17, 10:36 AM
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You shouldn't have broken at 315hp, something's dodgy with your tune or your trailing coil.
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Old 10-29-17, 12:01 PM
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It was a s4 plate that cracked on the dyno.. it had a couple of detonations due wastegate plumping. So im going to replace the rear plate with a s5 one.
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Old 10-30-17, 08:52 PM
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at 300hp i too cracked a rear iron, its not the hp or the turbo, its the tune!

you will still fk the motor up. my waastegate stuck closed and overboosted, pop.
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Old 10-30-17, 09:15 PM
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Did yours have a s5 end plate?
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Old 01-06-19, 08:07 PM
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dowling the engine is insurance ..... maybe find a new tuner..... good luck
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Old 01-06-19, 08:24 PM
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Detonation is usually what cracks plates, generally the rotor tips touch the rotor housings and this gets transfered to the dowel pins.

We have found that adding a set of solid dowels from pineapple racing and our 10mm stud kit will keep the plates from cracking if you detonate. You will find the rotors dented on s5 or later and warped seals( if using aftermarket) if you detonate with the above parts. Stock seals usually grenade unless its very light regardless of mods. You can still crack s4 plates with the oem seals and not have any internal damage other than plates cracked.

13b stud kits
Rx7 Rotary Performance Parts

Last edited by Turblown; 01-06-19 at 08:26 PM.
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