Drop in Mahle pistons?

[Imma Sssnaake]

I noticed Mahle just released a drop in piston for the Voodoo. I was wondering if anyone has had experience with these and boost? I’d like to do a twin turbo setup on my ‘18 (gen1 voodoo) and i’m looking to make it as reliable as possible considering a rebuild is in the $20k ball park. Would this help strengthen the motor? If they only make a drop in piston, does that mean they aren’t worried about rods? Is there anything else in the motor I could upgrade for boost without having to rebalance the motor? Maybe valve springs, drop in pistons, and the obvious opg/cs?

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[honeybadger]

OEM pistons are actually quite good. There's nothing inherently wrong with them and the motor can't handle low boost just fine if it's a healthy motor.

How much boost do you plan to make? What do you plan to use it for?

 

[Imma Sssnaake]

OEM pistons are actually quite good. There's nothing inherently wrong with them and the motor can't handle low boost just fine if it's a healthy motor.

How much boost do you plan to make? What do you plan to use it for?

I’m glad to see you in here lol, you seem to be the guy with the answers to these motors. But hellion sleeper on e85, would like to be in the 750whp area. Ive heard it can be done with as little as 5-6lbs with twins. Motor seems to be healthy, it only has ~3k miles on it as it is motor #2. It’s admittedly seen 3-4 money shifts (3rd to 2nd) as this was my first manual car in a hot minute and had to brush up, but still runs and pulls perfectly fine. I have JLT catch cans on both sides, not a drop in driver side but a very thin layer of oil in the passenger side after a couple hundred miles of driving with some 8k pulls. It’s a weekend car, mainly just Mexico stuff and the maybe once a year roll racing at street car takeover. Car will be remote tuned by FatHouse.

 

[olaosunt]

As @honeybadger said the stock OEM pistons are pretty good and are actually made by Mahle .... I have had the “drop in’s” side by side and they look almost the same as the OEM Gen 1 voodoo pistons .
I am pretty sure they are exactly the same pistons used in the “Gen 2” voodoo motors .

They are slightly different from the Gen 1 pistons (different rings - the Gen 1 rings are no longer available at Mahle ) . They are the same pistons used in the 5.2 Alluminator and 350 PS motor .

I would not really consider them an ”upgrade “ but I used them in CP build with the predator block /5.2 crank below .

if building for boost I would at least “upgrade“ the rods . I bent a couple of stock ones with a 2.9 whipple at moderate boost .

On the top end , head studs and a valve spring upgrade at a minimum.
i would also upgrade the the cam phasers to the low leak GT350 R ones .

 

[olaosunt]

My builder even thinks the Gen 1 pistons may be better for boost since they decreased the ring gap on the later pistons .

I will be building a “spare “ voodoo motor with a set is brand new Gen 1 pistons (had them for a while ) and the Gen 2 block .

I have used the Gen 1 pistons in other builds including rebuilding a stock voodoo motor (below )-just rod upgrade - and a couple other CP builds .

 

[olaosunt]

The Alluminator and FPS 350 engine use the Manley H rods -they are specific for the Mahle pistons.
They have a tapered small end and
use a smaller pin .
They are definitely an “upgrade” to the OEM rods in the voodoo and still relatively light at 600 gm.
see below

 

[Imma Sssnaake]

The Alluminator and FPS 350 engine use the Manley H rods -they are specific for the Mahle pistons.
They have a tapered small end and
use a smaller pin .
They are definitely an “upgrade” to the OEM rods in the voodoo and still relatively light at 600 gm.
see below

But these would not be considered a drop in, correct? Im guessing it would need a rebalance. And when you say moderate boost, how many pounds? And what fuel?

 

[olaosunt]

But these would not be considered a drop in, correct? Im guessing it would need a rebalance. And when you say moderate boost, how many pounds? And what fuel?

The “drop in” Mahle pistons are the SAME they use in those Ford performance engines.

I am pretty sure they the same pistons in the 2019+ voodoo engines. Not sure if they would need rebalancing in a pre 2019 engine ... but honestly don’t think they are upgrade .

12-13 psi on race gas at the time/whipple tune . RPG rebuilt that motor for me and when he tore it down he thought there was evidence of heads lifting which could have contributed to the rods bending.
Ended up sleeving the motor because the Lining was scored.
He rebuilt with different pistons - diamond (voodoo spec ) Manley rods/valve spring upgrade and head studs.

 

[olaosunt]

But these would not be considered a drop in, correct? Im guessing it would need a rebalance. And when you say moderate boost, how many pounds? And what fuel?

sorry misread .... yes would need to be rebalanced . No , not a “drop in “ rod .
.

 

[Imma Sssnaake]

The “drop in” Mahle pistons are the SAME they use in those Ford performance engines.

I am pretty sure they the same pistons in the 2019+ voodoo engines. Not sure if they would need rebalancing in a pre 2019 engine ... but honestly don’t think they are upgrade .

12-13 psi on race gas at the time/whipple tune . RPG rebuilt that motor for me and when he tore it down he thought there was evidence of heads lifting which could have contributed to the rods bending.
Ended up sleeving the motor because the Lining was scored.
He rebuilt with different pistons - diamond (voodoo spec ) Manley rods/valve spring upgrade and head studs.

12-13 lbs is a good bit for a SBE gen1. You think with 5-7lbs on E85 and the mods you listed I should be safe to beat on it?

 

[olaosunt]

... my luck is know to suck too .

Plenty of stock motors still kicking at even higher boost /power levels than when mime failed .
At 5-7 lbs I would not touch motor .

 

[olaosunt]

The Alluminator and FPS 350 engine use the Manley H rods -they are specific for the Mahle pistons.
They have a tapered small end and
use a smaller pin .
They are definitely an “upgrade” to the OEM rods in the voodoo and still relatively light at 600 gm.
see below

Below is a pic of the bent rod .
I would definitely upgrade them before the pistons if you are rebuilding the motor .

 

[olaosunt]

Here is exactly what RPG said after tearing down the motor about why it failed .
Head studs would definitely help with head lift .
The Gen 2 blocks have the longer 12 mm head bolts so block is less prone to crack.

 

[john@fatfab]

The only thing I would do to a stock voodoo engine would be oil pump gears. Anything beyond that starts with sleeving the block. Be prepared to spend some coin to do so.

 

[olaosunt]

Wh

The only thing I would do to a stock voodoo engine would be oil pump gears. Anything beyond that starts with sleeving the block. Be prepared to spend some coin to do so.

why so ?
sleeving one is not going to cost anymore than sleeving a coyote .
Ans if you don’t want to go “all the way” , like the Coyote I still think mild Valve train upgrades ,head studs and rod upgrade maybe worth it.especially if you are not planning to make north or 1300 whp.
RPG rates his Gen 2 5.2 short blocks(with rod upgrade ) up to 1300 whp
https://rpgracingengines.com/product/rpg-5-2l-level-2-short-block/

Below that you are more likely to lift heads or bend a rod before you crack a block especially if you have 2019+ which has the Gen 2 block .

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