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Discussion Starter · #1 ·
Ok, so here's the question. With our piston's compression ratio being rather high, even a 50 shot of spray scares me. Is there a thicker head gasket out there that would lower the compression enough to make me feel better about putting nitrous on my tC? I'm not even sure i want to do is as i've always viewed nitrous a cheap power and only for V8s in the past, but i'd like to give my car a little something more without putting the $3500+ for a turbo kit. I've pretty much given up on the supercharger as they have yet to get it CARB legal and it doesn't seem as though they will. Any help here please? Thanks!
 

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Lowering the compression won't be any significant help to save the engine, and it will certainly make you lose power unless you are at WOT. Two of the three C's still apply, cams and compression are your friend for making power. There is also a unique slanted squish area on the pistons that depends on the head being at the correct height from the top of the piston. A thicker headgasket will defeat this, and will make the engine more detonation prone, not less.

As strong as this engine is, there is very little a 50 shot could do to hurt it unless you get a backfire. A backfire could result in a cracked intake manifold (since it's plastic), and the design of the intake is NOT nitrous friendly. With the plenum on the bottom, it just invites fuel puddles to form and create ideal conditions for a backfire through the intake. I would be a LOT more concerned about this than a problem with the basic engine. Scionspeed is making a lot of power with the stock configuration (I think they are going to start finding the weak links pretty quickly now) and it is well over twice the factory rated output, as is typical for Toyota engine designs. I am a bit concerned about the gearbox and driveline at their ~500 hp numbers though, Toyota is NOT well known for strong gearboxes.
 

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Former '05er
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It's not a weakness, they just aren't as robust as their engines. The W-58 used in the MkIII and MkIV NA Supras is a perfect example. Double the torque, and it shortens the service life dramatically. This doesn't mean it's weak, it's just not as strong as the engine that will take more than twice the rated output.

The MkIV Supra TT was an anomaly, it has a Getrag gearbox that looks like it was designed for a medium duty truck and has survived more than three times the factory rated power. The rest are just not as good.
 

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I wouldn't go dry, but I'd figure out a way to keep the nitrous nozzle from dripping into the plenum. The last thing you want is a fuel puddle in that plenum.
 

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Ironhead
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yeah, i had this conversation with lance not too long ago. backfire was the main concern with nos. also, he can explain the logic behind not going nos if you are going s/c, though power wise for me the ideal set-up would be the trd s/c with a 50 shot. not a good idea with a supercharger, though. backfire and your s/c is toast.
 

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Assuming the fuel mods they give you are sufficient to support an extra 50 hp over the standard SC upgrade. I'm still wondering how the guys with the turbo kits are getting past the fixed fuel pressure problem. I guess I need to dig deeper into the returnless system design to understand what they've done.
 
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