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Discussion Starter #1
I'm gunna be supercharging my engine with a Kenne Bell 2.1L Big Bore at 14 PSI, I have a stock top an bottom end. I want to get JE forged pistons, an Manley forged "H" beam connecting rods. But I don't know internals that well yet, an i have no idea what length connecting rod or piston measurements that will fit a stock top an bottom end :sorry. Any help is VERY appreciated, thank you.
P.s. I have 4.10 gears... Is that a bad combo with the supercharger?

- Dave
 

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Dave, both companies make parts specifically for these motors which alleviates the need to just look for a piston or rod with the dimensions. std bore on these motors is 3.552" and you should look for a piston with around a -17cc or -18cc dish to give you mid 9 to 1 compression ratio. As for rods, big/little end width is .940," big end diameter is 2.239," center to center is 5.933," little end diameter depends on choice of piston pin size and comes in a couple sizes.

Rods: http://www.manleyperformance.com/dl/2011/rods.pdf

Pistons: FORD - 4.6L / 5.4L MODULAR - JE Pistons
 

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Discussion Starter #3
I checked out the JE piston site, and can't seem to find a "2v" section on the 4.6L modular. Plus I would like to run 8.5:1 compression pistons due to 14 PSI.
And isn't the length of the rod suppose to be perfect?:confused: I'm just tryin to cover all aspects so less chance of something going wrong.
Thanks again.

- Dave
 

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I checked out the JE piston site, and can't seem to find a "2v" section on the 4.6L modular. Plus I would like to run 8.5:1 compression pistons due to 14 PSI.
And isn't the length of the rod suppose to be perfect?:confused: I'm just tryin to cover all aspects so less chance of something going wrong.
Thanks again.

- Dave
You will be fine running a 19cc piston which is around 9.2:1 with 14 psi, plus you would get good off boost power/mileage.

the rods will be correct length if bought for a 4.6l. are you talking about deck hieght?
 

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King Trashmouth
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I checked out the JE piston site, and can't seem to find a "2v" section on the 4.6L modular. Plus I would like to run 8.5:1 compression pistons due to 14 PSI.
And isn't the length of the rod suppose to be perfect?:confused: I'm just tryin to cover all aspects so less chance of something going wrong.
Thanks again.

- Dave
4v and 2v pistons are interchangeable, so I doubt the distinction between the two would be made.

Conrods should all be the same length as stock, unless you're buying an explicitly stroker kit, so I wouldn't sweat that.

As far as piston dish you might be out of luck, I don't think I've seen any dish lower than 18cc. Even with 14PSI I don't think ~9:1 CR would be an issue, especially if you are upgrading the rotating assembly. I've seen comparable amounts of boost run on higher compression engines without a significant problem.
 

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mm's nitrous mod
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+1 to limited. boy knows his stuff :)

there are other options for rods and pistons as well. 14psi isnt a big deal, easily doable on pump gas even on stock compression.
 

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Discussion Starter #7
You will be fine running a 19cc piston which is around 9.2:1 with 14 psi, plus you would get good off boost power/mileage.

the rods will be correct length if bought for a 4.6l. are you talking about deck hieght?
Yes I am talking about deck height.
An thanks "limited", that helped my decision by a great amount.
 

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+1 to limited. boy knows his stuff :)

there are other options for rods and pistons as well. 14psi isnt a big deal, easily doable on pump gas even on stock compression.
+1,

I wouldn't drop the compression down to 8.anything for 14psi. Plenty of people run 9.4ish with a lot more boost than that.
 

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I know of a guy running 10:1 compression with 23psi from a twin screw. You'll be fine with any compression ratio with boost as long as whoever is tuning the car is decent. I personally wouldn't go any lower than stock to be honest. I'd run 10:1 as well with this setup. But that's just me.
 

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i just dyno'd my kb 2.1 with the 14psi pulley on thursday. i have a forged bottom end with stock compression ratio, all good here.
 

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Discussion Starter #12
Thanks guys, I have one more question... how hard is it to swap out the rods an pistons on my own? Or do I need that professionally done?
Thanks again.
- Dave
 
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