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Old 11-13-2014, 12:58 AM
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Default Why not oem pistons

That's the question I have. What is the advantages of running either Vitaras or a set of aftermarket pistons ?
Old 11-13-2014, 02:35 AM
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Default Re: Why not oem pistons

OEM pistons are cast. Aftermarket pistons are forged. OEM pistons have ring lands made out of tin cans. Aftermarket pistons have ring lands that are made out of real metal, with real thickness to them that won't cry at the first sign of a hard time. This is all really basic stuff you could have found out using Google.
Old 11-13-2014, 05:05 AM
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Default Re: Why not oem pistons

The main advantage of non-OEM Honda pistons is that the ringlands will stay attached to the piston, rather than ending up in the oil pan. Basically, forged pistons can take more abuse than a cast piston without catastrophic failure.

Blown Ringland Pic
Old 11-13-2014, 05:16 AM
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Default Re: Why not oem pistons

Ive often wondered if OEM pistons were used with bigger ring gaps and more piston to wall if they would hold up much better.
Old 11-13-2014, 05:56 AM
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Default Re: Why not oem pistons

We used to pound oem pistons in B and H motors and never broke any in the 3-400whp range. Nowadays where 500-1000 is the norm, nobody uses them. I would still run oe pistons in mild street builds with no worries.
Old 11-13-2014, 09:15 AM
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Default Re: Why not oem pistons

Originally Posted by Runnerdown
We used to pound oem pistons in B and H motors and never broke any in the 3-400whp range. Nowadays where 500-1000 is the norm, nobody uses them. I would still run oe pistons in mild street builds with no worries.
total agree with you
Old 11-13-2014, 07:36 PM
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Default Re: Why not oem pistons

Originally Posted by Muckman
Ive often wondered if OEM pistons were used with bigger ring gaps and more piston to wall if they would hold up much better.
I've thought about this myself.
Old 11-14-2014, 02:16 AM
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Default Re: Why not oem pistons

I'll be running standard internals in my H motor on about 300hp
Old 11-14-2014, 06:42 AM
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Default Re: Why not oem pistons

Ring lands blow off around 350whp

I'm shooting for about 350-375 in spring with lots of tuning .... And it'll prob blow..

Then no more fkn around lol
Old 11-14-2014, 06:59 AM
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Default Re: Why not oem pistons

I thought another weak point is the rods? It wouldn't make sense to just upgrade rods without pistonz
Old 11-15-2014, 09:28 PM
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Default Re: Why not oem pistons

Vitaras are nice because of the T6 heat process that makes them stronger. Stock rods on a D15/16 is only like 220-250whp, Most kits for Vitaras are fairly cheap and most give a compression of like 8.5:1.
Old 11-15-2014, 11:59 PM
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Default Re: Why not oem pistons

Originally Posted by Hidenplanvew
Vitaras are nice because of the T6 heat process that makes them stronger. Stock rods on a D15/16 is only like 220-250whp, Most kits for Vitaras are fairly cheap and most give a compression of like 8.5:1.
Which is ******* horrible.
Old 11-16-2014, 01:42 PM
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Default Re: Why not oem pistons

I'm not sure but this 8:5:1 is very close to the stock engine compression for a D16Z6. What are the advantages in using a stock length forged rod than a shorter one in a turbo set up?
Old 11-16-2014, 01:53 PM
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Default Re: Why not oem pistons

8.5:1 is not "very close" to 9.2:1. It's nearly a point off. The correct question for your question is "what are the disadvantages of running a shorter rod", and that's a pretty long list. Reducing compression reduces volumetric efficiency, which means less power and poorer gas mileage. Changing the rod length ***** with the rod:stroke ratio, which also negatively affects your powerband, VE, and MPGs. It has literally zero advantages, and multiple HUGE disadvantages. There's no reason to do it.
Old 11-17-2014, 07:41 PM
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Default Re: Why not oem pistons

stock rod length= 7.5:1 custom length = 8.5:1. I like Vitaras for cheap "builds" or "Street" cars, but yes low compression has its downside. It also has some welcome benefits likes, Like forgiveness being one of the biggest. I have had both low and "high" compression turbo builds, yes the high compression was nice, but for triple the price it did hurt the wallet a little more.
Old 11-18-2014, 03:17 AM
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Default Re: Why not oem pistons

Originally Posted by NotARacist
8.5:1 is not "very close" to 9.2:1. It's nearly a point off. The correct question for your question is "what are the disadvantages of running a shorter rod", and that's a pretty long list. Reducing compression reduces volumetric efficiency, which means less power and poorer gas mileage. Changing the rod length ***** with the rod:stroke ratio, which also negatively affects your powerband, VE, and MPGs. It has literally zero advantages, and multiple HUGE disadvantages. There's no reason to do it.

Ive done it and all I can say is 7.8:1 is ******* horrid. You have drive around at like 8" everywhere u go cuz it makes no power outside of boost even with more timing. I waas barely getting 28mpg and get low 30s with my 2 liter gsr turbo. It made 240whp @14 psi with a saab td05 15t went mid 13s @105 but was certainly a dog around town. I put 12k miles on it that year.

Ok now all said and some may disagree but im going to use the nippon turbo b series pistons/ stock rods w/ arps to make a very reliable 300-350whp at some point in the next few years. I think they are a shade under 9:1 and can get mid 9's with some milling
Old 11-18-2014, 07:39 AM
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Default Re: Why not oem pistons

Originally Posted by blackeg
Ive done it and all I can say is 7.8:1 is ******* horrid. You have drive around at like 8" everywhere u go cuz it makes no power outside of boost even with more timing. I waas barely getting 28mpg and get low 30s with my 2 liter gsr turbo. It made 240whp @14 psi with a saab td05 15t went mid 13s @105 but was certainly a dog around town. I put 12k miles on it that year.

Ok now all said and some may disagree but im going to use the nippon turbo b series pistons/ stock rods w/ arps to make a very reliable 300-350whp at some point in the next few years. I think they are a shade under 9:1 and can get mid 9's with some milling
Yep I am using the Nippon b series pistons in my LS with stock rods, ARP bolts and head studs. I have been beating the **** out of it since I built it this summer and its holding up great at around 300whp. I was originally planning on a stock OEM rebuild, but ended up needing to bore the cylinders so instead of buying OEM pistons I bought the Nippon's for $180. They have much thicker ringlands then OEM pistons. I think Nippon pistons are the same compression as stock LS pistons...

What I'm curious about is the power limits of the stock LS rods, particularly the torque limit since the shitty flow of the LS head makes more torque to HP vs a vtec head. I'm gonna get my car on a dyno soon and push the power to around 350whp and I assume about 300 or more torque.

Last edited by boosted94gsr; 11-18-2014 at 10:14 AM.
Old 11-18-2014, 03:02 PM
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Default Re: Why not oem pistons

thats it right there man! if you are doing an 81.5mm build or if the pistons need replacing even at 81mm for whatever reason there is no reason to put oem back in there if you ask me.
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