Technical Cons of Forged Pistons in N54??

[JonEQuest]

I am rebuilding my engine and plan to do some upgrades. I was about to order some forged rod and pistons but I have read that forged pistons expand more to heat and would cause piston slap and increased wear when the engine is cold. So basically every day when I start up. I am staying at or below 650hp so not sure now if I should do the forged pistons or not. Anyone have experience with going to forged pistons and any drawbacks? I daily this car and make a lot of small trips throughout my day so easy drive ability is a must.

 

[ShocknAwe]

If it's a DD and you're staying in the 600whp ballpark keep the bottom end as stock as possible.

Just my opinion. I'm sure others will come in.

 

[desmo11]

No cons to good pistons. I'd run Mahles.

 

[JohnDaviz]

I have read that forged pistons expand more to heat and would cause piston slap and increased wear when the engine is cold. So basically every day when I start up.

Yes. Due to the material properties 4032/2618 you need adjusted piston wall clearances.

From JE:
A 2618 piston will expand 15 percent more than a 4032 version. This, as we've mentioned, is the reason a 2618 piston requires more clearance and as a result will be slightly noisier when cold as opposed to a comparable 4032 forging.

BUT the heating of the pistons doesn´t take as long as you might think. It is not like warming up your oil.

 

[JonEQuest]

Yes. Due to the material properties 4032/2618 you need adjusted piston wall clearances.

From JE:
A 2618 piston will expand 15 percent more than a 4032 version. This, as we've mentioned, is the reason a 2618 piston requires more clearance and as a result will be slightly noisier when cold as opposed to a comparable 4032 forging.

BUT the heating of the pistons doesn´t take as long as you might think. It is not like warming up your oil.

I might just go with the 4032 piston. The 2618 JE are out of my budget anyway.

 

[JohnDaviz]

I am running the Mahle Forged 2618 pistons and as Mahle is the OEM supplier for the stock pistons this is the way to go in my opinion. You may want to check them out.

 

[ShocknAwe]

Mahle if you must. Agree with the above.

 

[desmo11]

You want 2618 not 4032. Mahle is good people, I have done quite a few pistons with them and they are good to work with.

 

[Traf]

2618 is the also the most knock resistant alloy of the two, very useful feat on a N54.
As far as expension go, while 2618 will expend more than 4032, the final dimensions when at operating temperature are the same as 4032.
I'm guessing piston manufacturers have accounted for that and 2618 pistons are most likely smaller when cold.

 

[JonEQuest]

You want 2618 not 4032. Mahle is good people, I have done quite a few pistons with them and they are good to work with.

I am on a budget so I think I am just going to save $500 and go with some affordable 4032 pistons. I don't track this car so any upgrade will be a plus.

 

[JohnDaviz]

I am on a budget so I think I am just going to save $500 and go with some affordable 4032 pistons. I don't track this car so any upgrade will be a plus.

Have you even checked the prices?

My Mahle were cheaper than most competitors at that time.

 

[langsbr]

The only 4032 pistons I've found for the N54 are china no brand ones. Also, the only 2618 pistons I've found are brand name - Mahle, manley, JE.

The 4032s while being forged are going to be brittle and not a great choice for the N54. I would argue you would be just as good using the stock pistons with a bigger ring gap and saving the money rather than putting it into 4032 pistons that would suffer the same fate (if not worse) than the stock ones.

This is not one of the items you can easily re-do, so I'd suggest spending the money where it counts.

Aren't you doing rods as well? What rods did you go with? I'd argue you'd be just as well served by china rods vs brand name ones, and save a couple hundred bucks that can go towards better pistons.

 

[JonEQuest]

The only 4032 pistons I've found for the N54 are china no brand ones. Also, the only 2618 pistons I've found are brand name - Mahle, manley, JE.

The 4032s while being forged are going to be brittle and not a great choice for the N54. I would argue you would be just as good using the stock pistons with a bigger ring gap and saving the money rather than putting it into 4032 pistons that would suffer the same fate (if not worse) than the stock ones.

This is not one of the items you can easily re-do, so I'd suggest spending the money where it counts.

Aren't you doing rods as well? What rods did you go with? I'd argue you'd be just as well served by china rods vs brand name ones, and save a couple hundred bucks that can go towards better pistons.

I am planning on probably getting Kingtec rods and maybe their pistons. I see your point on the stock vs. Chinese ones. I was assuming any 4032 pistons would be slightly better than stock.

 

[ShocknAwe]

Can't compare across metals forged isn't a standard of quality IMO. get the mahle or keep it stock.

 

[JohnDaviz]

I am planning on probably getting Kingtec rods and maybe their pistons. I see your point on the stock vs. Chinese ones. I was assuming any 4032 pistons would be slightly better than stock.

Kingtec? You are kidding right? If you want to be cheap. PLEASE go with:

FCP Rods
Mahle Pistons

you won´t get way cheaper with the poor stuff you mentioned. (oh you will. Because Kingtec is really not good)

I mean if you are already planning on going Kingtec...

Look. We just want to help you. But please don´t go that route.

But if you want. Go to the supplier directly:

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Kingtec Racing Engine N54b30 N54 Tuned N55 Forged Connecting Rod For Bmw Twin Turbo Exhaust Engine I6 - Buy N54b30 N54b30 A For Bmw N54b30 For Bmw E60 N54b30 For Bmw E30 N54 For Bmw N54 E60 n54 Turbo N54 Rods Product on Alibaba.com

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So you will get a set of Pistons for around 100 USD and Rods for around 500 USD

Oh Edit:

Kingtec Racing N54 Forged Pistons And Rods For Bmw E60 E61 535i F01 740i 3.0 N54b30 Turbo Kit - Buy For Bmw N54 Forged Pistons And Rods n54 Racing Piston for Bmw N54 Connecting Rods Product on Alibaba.com

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Everything for around 1k USD

 

[JonEQuest]

Kingtec? You are kidding right? If you want to be cheap. PLEASE go with:

FCP Rods
Mahle Pistons

you won´t get way cheaper with the poor stuff you mentioned. (oh you will. Because Kingtec is really not good)

I mean if you are already planning on going Kingtec...

Look. We just want to help you. But please don´t go that route.

But if you want. Go to the supplier directly:

Cnc Car Part Kingtec Racing Forged Pistons Manufacturers For Bmw M54 N54 S63 B58 M50 N20 S55 M52 N55 N63 B48 S85 S65 S62 Engine - Buy Forged Piston For Bmw F32 X5 F15 E87 E82 F22 E91 racing Forged Pistons For Bmw E36 E60 E30 E39 F10 racing Piston Man

Cnc Car Part Kingtec Racing Forged Pistons Manufacturers For Bmw M54 N54 S63 B58 M50 N20 S55 M52 N55 N63 B48 S85 S65 S62 Engine - Buy Forged Piston For Bmw F32 X5 F15 E87 E82 F22 E91 racing Forged Pistons For Bmw E36 E60 E30 E39 F10 racing Piston Manufacturers For Bmw E90 E46 E92 F30 Product on...

www.alibaba.com

Kingtec Racing Engine N54b30 N54 Tuned N55 Forged Connecting Rod For Bmw Twin Turbo Exhaust Engine I6 - Buy N54b30 N54b30 A For Bmw N54b30 For Bmw E60 N54b30 For Bmw E30 N54 For Bmw N54 E60 n54 Turbo N54 Rods Product on Alibaba.com

Kingtec Racing Engine N54b30 N54 Tuned N55 Forged Connecting Rod For Bmw Twin Turbo Exhaust Engine I6 - Buy N54b30 N54b30 A For Bmw N54b30 For Bmw E60 N54b30 For Bmw E30 N54 For Bmw N54 E60 n54 Turbo N54 Rods Product on Alibaba.com

www.alibaba.com

So you will get a set of Pistons for around 100 USD and Rods for around 500 USD

Oh Edit:

Kingtec Racing N54 Forged Pistons And Rods For Bmw E60 E61 535i F01 740i 3.0 N54b30 Turbo Kit - Buy For Bmw N54 Forged Pistons And Rods n54 Racing Piston for Bmw N54 Connecting Rods Product on Alibaba.com

Kingtec Racing N54 Forged Pistons And Rods For Bmw E60 E61 535i F01 740i 3.0 N54b30 Turbo Kit - Buy For Bmw N54 Forged Pistons And Rods n54 Racing Piston for Bmw N54 Connecting Rods Product on Alibaba.com

www.alibaba.com

Everything for around 1k USD

The $1,000 total price is what's making me think about it. I'm the first to make fun of Chinese stuff but the fact is these are metals manufactured in factories and Kingtec happens to make a lot of pistons and rods for a lot of cars. I've searched for negative reviews of Kingtec and I haven't found anything yet. They make pistons for Toyota Saab Honda BMW Mercedes skoda I figured with them making that much stuff if the product was crap I'd find a bunch of bad info about them. So far I found nothing in the way of negative reviews. I also look at it like my VIV turbos. They are made in China and people dog them, but the last set I had ran hard for 4 years and they still have no shaft play. I simply had one wastegate weld break. I don't simply trust them for no reason, I just figure if a company makes 100,000 of these parts a year, then they're probably pretty good at it. I also found some reviews where they weighed them and they seem to be very balanced with the exact same weight for every piston and Rod. I'm kind of looking at it like even if they're no better than stock, my stock ones are very old and have run many heat cycles so even new stock quality ones would be better than old stock ones in my opinion. Do I think they're even 1% better than Mahle or JE, etc. no way. But so far everything I've bought Chinese for my car from charge pipe blow off valve intercooler and turbos has worked and lasted just as long as other people with name brand stuff. The only reason I'm apprehensive is because this is inside the core of the motor.

 

[desmo11]

2618 is a higher strength alloy at temperature than 4032. As I recall, 4032 is better for abrasive wear, and thus is used frequently in 2 stroke pistons. Forging vs. billet is meaningless, as at piston temperatures the benefits one would associate with a forging (or shot peening for that matter) go away very quickly in comparison to a piston's design life.

 

[langsbr]

The link for the pistons is the price per piston, so about 500 for pistons as well. I get that its appealing to be $1,000 for all the parts - but when you consider how much everything ELSE costs to rebuild an N54, $500 bucks is chump change to have a piston that you KNOW will perform better and have better durability. I think the 4032s would be fine in an NA motor, but with 20+ psi of boost on a motor that is already octane limited, going with a piston that while being forged, is made of a much more brittle material, is a fool's errand.

What is your full plan on this motor? Just rods and pistons and new rod bearings, or are you going to pull the crank too?

 

[JonEQuest]

The link for the pistons is the price per piston, so about 500 for pistons as well. I get that its appealing to be $1,000 for all the parts - but when you consider how much everything ELSE costs to rebuild an N54, $500 bucks is chump change to have a piston that you KNOW will perform better and have better durability. I think the 4032s would be fine in an NA motor, but with 20+ psi of boost on a motor that is already octane limited, going with a piston that while being forged, is made of a much more brittle material, is a fool's errand.

What is your full plan on this motor? Just rods and pistons and new rod bearings, or are you going to pull the crank too?

I am rebuilding a motor that had a bad head gasket and the rod bearings had some signs of wear, so I am doing the crank bearings too. I guess I should just spend the extra money and get the Mahle pistons for peace of mind. I see the argument for a more bulletproof metal especially with these known for ring land issues.
P.S. I thought the stock N54 (and other engine) pistons were 4032. Are they not?

 

[JohnDaviz]

P.S. I thought the stock N54 (and other engine) pistons were 4032. Are they not?

That is an interesting question. I only know they are from cast and not forged.. but which alloy?!