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Old 11-25-2002, 11:00 AM   #1
konnection
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Need advice on good piston ratios?

I will be rebuilding my engine (4G63 Turbo) sometime soon and need some good advice from everyone... I plan on replacing my oem pistons and rod with JE and Crower stuffs. My goal in the future is to get at least somewhere in the 600 HPs. Now with the JE Racing piston thing what is the best ratio i can go with and still be driveable with 91 octane? (The highest octane i can find around town is 91!) Also, what is the best pistons/rods out there that you think i should consider buying to get to my goal?
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Old 11-25-2002, 11:52 AM   #2
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600hp on 91 octane? Or are you talking with race fuel?

I would imagine that 8.5 would be the best. the 9.0 would be nice as far as helping with spool up, but I think with that high of a compression you will have nothing but problems on 91 octane.
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Old 11-25-2002, 03:57 PM   #3
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600hp....hmmmmm. uhhh not to steer you from your plans, but you have a lot of research to do before you jump into that power range. by saying that you are going to run 91 octance and 600hp in the same sentence i can tell you have some work ahead of you....your talking years to build, shit loads of broken parts, LOTS of tuning, more broken parts, and its going to be a track only car. no 600hp dsm is going to be driven on the street.

here check this out. www.Garychiosawdgsx.com
this will give you an idea of how many parts you will need to buy. click "setup" to see them.

8.5 is nice
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Old 11-25-2002, 06:11 PM   #4
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Its a long ways but ill try to get there little by little... and yes it gonna be a track thing but still i wana be able to drive it around town every once in awhile... but thanks on your opinions
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Old 11-25-2002, 07:40 PM   #5
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Hmm you cannot run 600HP with 91 octane, I wish I know the math to prove it but I'm pretty sure it cannot be done on pump gas alone.

You would need bigger displacement, like a turbo 7.0 litre engine, hehe.
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Old 11-26-2002, 01:24 AM   #6
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i dont think he is trying to say he wants to make 600hp on 91 oct, i think he is saying he wants to be able to make that much power but have it still streetable on pump gas. which i dont know if you will be able ot accomplish with such a hight hp goal. goodluck.
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Old 11-26-2002, 04:28 AM   #7
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" i dont think he is trying to say he wants to make 600hp on 91 oct, i think he is saying he wants to be able to make that much power but have it still streetable on pump gas. which i dont know if you will be able ot accomplish with such a hight hp goal. goodluck. "
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Yea thats what i meant... I read somewhere (i forgot) that if you went with 9.0:1 ratio (as an example) all you gota do is move the decimal one place to the right and that will be the octane (90) you'll want to be around with.. is that true ?
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Old 11-26-2002, 07:09 AM   #8
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Quote:
Originally posted by konnection
Yea thats what i meant... I read somewhere (i forgot) that if you went with 9.0:1 ratio (as an example) all you gota do is move the decimal one place to the right and that will be the octane (90) you'll want to be around with.. is that true ?
No. The ability of the engine to run on certain gas octane rating is determined by its detonation threshold that is affected by several factors such as the engine's static and dynamic compression, combustion chamber design, intake charge temperature, boost level, valve and ignition timing, etc. You'll be able to run 91 octane gas with 9:1 compression, but anything higher will leave very small window for error. In my opinion, you should definitely reconsider going with JE pistons for street use due to their higher expansion rate requiring looser piston-to-wall installation. Your best bet might be Wiseco 8.8:1 pistons.
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Old 11-26-2002, 09:17 AM   #9
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Quote:
Originally posted by Taboo

In my opinion, you should definitely reconsider going with JE pistons for street use due to their higher expansion rate requiring looser piston-to-wall installation. Your best bet might be Wiseco 8.8:1 pistons.
Nicely put, or Arias or Ross as they all expand the least. I converted to custom piston design Arias now.

Now for the original post,

600 WHP is a figure that is easily mentioned or tossed around, and with the content of this post, it sounds like you have no idea about HP (Piston Ratio?).

How do you plan on making this figure? Are you going to do this yourself, or have someone build it for you?
I am just curious? Are you an engine builder? Do you know all the Turbos available for this kind of setup? Do you understand how a turbo compressor works with boost vs efficiency? What kind of fuel mgmt and do you know how to tune with a wideband? Do you know how to rebuild trannies, or at least have a hookup for tranny work?

600 WHP is insane, and not that easily attainable, and for your information, most 10 second cars are making 500-530 WHP to go low 10's, So I gues your goal is mid 9's?

Just so you know, noone is going to build you a 600 WHP car as most shops don't have that kind of power for their own (High Budget) race cars. Some claim to have made this power, but I highly doubt it. I can only think of a Extreme, Jeff Hill and Shep making this kind of power with Nitrous (lots and lots of nitrous)....The MPH will show your HP, not the ET. That would be over the 145 MPH range.
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Old 11-26-2002, 06:10 PM   #10
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"How do you plan on making this figure? Are you going to do this yourself, or have someone build it for you?
I am just curious? Are you an engine builder? Do you know all the Turbos available for this kind of setup? Do you understand how a turbo compressor works with boost vs efficiency? What kind of fuel mgmt and do you know how to tune with a wideband? Do you know how to rebuild trannies, or at least have a hookup for tranny work?"
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All i could think of is maybe get good internals and dont have to worry about breaking things on the inside... -- Whats everyones opinion? -- (for the long run) and no i wont be doing this maybe a machine shop will do (same with tranny... probably gonna go with TRE or BMTranny). All i want to worry about is the external stuffs and knowing that my internals are all damn good! Im not an expert yet (wanna be sometime... gonna get there) but i can do alot of external things... As far as turbo goes... i'll need more advice and research (everything else too). And the fuel thing, I think its gonna be easy... gonna try the AEM (cuz it looks cool and got a datalogger)... Damn, its alot of dough but i'm taking it little by little... Next year (2003) is my build date and theres gonna be alot of error and trial but thats what this forums all about (help when needed) rite?
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Old 11-26-2002, 06:41 PM   #11
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I am running JE 9.0:1 pistons in my street car. I'm capable of running 18-19 psi on 93-94 octane. You may be able to get 16-17 psi on 91 (thats if you had the exact setup I do), so your mileage may vary.

Yes, the JE's do have a large expansion rate. Unless they are up to temp. for a few minutes, I get phanthom knock (due to piston slap I assume) at WOT. Aries, Ross, Wiesco may be a better option.
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Old 11-26-2002, 07:32 PM   #12
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Quote:
Originally posted by konnection

All i could think of is maybe get good internals and dont have to worry about breaking things on the inside... -- Whats everyones opinion?
In my opinion, that's the right way to do it.. The block is the heart of the car and should be a solid foundation for anything else that might possibly come in the future. No matter if you decide to go with bigger turbo, ported head, nitrous or any other power-adder in the future, you know your block is going to be able to handle anything you throw at it and you won't have to pull it and beef it up with any future upgrade.
Going with the AEM EMS is a very wise decision as well - especially when aiming for high HP figures that would require the MAS elimination in the future. If you consider the cost of the old school TMO ECU/S-AFC/VPC/Datalogger combo and the fact that you're still stuck with the stock fuel and ignition maps you're just altering while having just very limited control, the bang for the buck ratio of the AEM standalone is simply unbeatable.
As for turbo, you might want to consider looking into some highly efficient Garrett of the twin ball-bearing GT series... Good luck.
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