2nd Generation Specific (1986-1992) 1986-1992 Discussion including performance modifications and technical support sections.

? strength of s5 Na Block

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Old Dec 27, 2003 | 05:51 PM
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From: eugene, or
? strength of s5 Na Block

how much horse do you think a s5 na black can handle..(not make just handle) I'm sure that it has it's weaknesses. so where are they... i have the ablity to beef up the block/dowling... but are there any other specific spots?? sorry can't afford to find out...
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Old Dec 28, 2003 | 12:30 AM
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From: eugene, or
bumpetty bump...
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Old Dec 28, 2003 | 12:43 AM
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From: fl
im just talking out off my *** but i dont realy know of any weakness specific to the s5 na that arent shared by all 13bs. stationary gears, apex seals, dowel pins all that good stuff. i think the turbo blocks have shlightly beefier oil passages so that may be a limmiting factor but not so much at a specific hp#
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Old Dec 28, 2003 | 12:44 PM
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From: eugene, or
looking for specific weak points. on the block that i can weld up or mill for more dowls ...
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Old Dec 28, 2003 | 01:23 PM
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Well, I can tell you that you won't bump intothose limits through any "normal" modding process. It's really only at around 400 HP that the engine starts to crack at the dowels, and you're only going to manage that with a big turbo, or a peripheral/bridge port and a significant amount of nitrous.
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Old Dec 28, 2003 | 02:05 PM
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From: eugene, or
Main reason for question is that I want to put my S4 hybrid on my 90 NA or when i blow the na i want to try building a TII block using s5 na side plates i still have all of my old s4 TII stuff since i went to a standalone.
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Old Dec 28, 2003 | 02:11 PM
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I'll put it this way:

If you're going to turbocharge the NA block, cracking the block is not going to be a major concern. Everyone I have seen that has turbocharged an S5 NA has blown their engine shortly after. That's not to say it can't be done, but from what I have seen it's a lot more twitchey then turbocharging the S4 NA.

If you are going to build a TII engine, use all TII parts. Don't use NA irons. The 4 port TII irons flow better then the 6 port NA irons, and have better porting potential.

Oh, and lose the 550CC secondaries in your NA (in your signature). You're just wasting fuel and losing power. NAs already run plenty rich on the 460cc injectors. In fact, you'll probably find 10 HP by LEANING out with the S-AFC.
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Old Dec 28, 2003 | 02:49 PM
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From: eugene, or
true on the injectors.. main reason for using was my 460's were leaking and i had 550's spare and yes it is kida leaned out i ported the hell out of the manifold( (cut it in half to fully extrude hone and ported the thbdy...) i do understand the high compression rotors being a problem under boost but that is what water cooling and racing fuel are for >>> i have been around the block and i'm on my 5th rx7. I do know what i'm talking about... i'm just trying to learn more from the people that are racing and breaking them..>>no fingers pointed<<
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Old Dec 30, 2003 | 11:13 PM
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From: eugene, or
oh come on guys i'd like to hear the about the limits of the motor,, what breaks specifically. pros and cons ..

search sucks >> dicussing is better arn't we motor heads.....

oh wait i was smoking tttoooo..
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