Piston Options

[waveblaster200]

Does anyone have info on Diamond 82.5mm pistons. I know a few folks are running them but I need the “sku” number or Id number to provide to diamond so they can pull the specs for them. They were unable to go searching for what I am looking for.

In the 82.5mm offering seems like JE is the only offering state side. Anyone have suggestions?

Power goals are 700+ whp on E85 with G25s. I am using IE H-Beam rods.

[Blazius]

As a budget option you can use the pistons from a 2.8V. They will take your goal given that stock pistons do it too and you will have the added benefit of the higher CR ratio IF you are going with E85.
Who's doing your tuning :)

[waveblaster200]

Alright that’s a option I did not know about. I believe this setup could be into the 850+ whp range with these turbos. But I don’t plan on running at those power level just due to longevity of the engine and drivetrain. I don’t mind spending the money on pistons at this point, I just want good parts and to do it correctly.

Brad will be doing my tuning once again, he does really awesome work. I can’t thank him enough. I’m very excited for the spring.

Engine parts off the top of my head
82 or 82.5mm pistons
IE H beams
Main studs/Vast girdle
Fluid damper

2.8 Heads & Cams
Supertech Inconel exhuast valves
Stock Intake valves
Supertech titanium springs and retainers
Headstuds

[belms4]

Mahle will make you some 82.5mm pistons as well. I got a quote back in 2020 from them for exactly that and at the time it was 5-6 weeks and $1,150. I like Mahle since they supplied the original pistons in the 2.7T engine. Haven't really heard of any issues with their pistons, but I do recall people mentioning issues in the past with JE pistons and the skirts blocking the oil squirters leading to problems. No idea if that's an issue of the past or still a thing today with JE.

Sent from my SM-F721U1 using Audizine Forum mobile app

[Silverex]

Pretty sure Monty has some Diamonds in his one engine I’d drop him a Dm

With that said I’m really surprised you called them and they asked for a SKU number….they are usually really good on helping you get what you need.

[evalegacy]

Power goals are 700+ whp on E85 with G25s. I am using IE H-Beam rods.

What version G25s are you going with? G25-550, 660 or? Similar build but haven't decided which turbo route to go. My power goals are 650-700whp on E85. Originally looked at GT28RS but shop pushed me towards G25s. I also thought about TTE780+ but then I started hearing about a lot of TTE turbo failures with them. GL with your build!

[waveblaster200]

Evalegacy: I went the G25-550 route. I got tired of all the China hybrid turbo options out there. I really wanted to go XR770s but either finding those or upgrading 605 to those didn’t happen. I wanted quality turbos that are modern tech and that are sold everywhere, that’s where the G25-550/660 ect come in. I am going the 550 route because I’d rather sacrifice some top end to gain earlier spool. These things should have a fun power band. My SRM RS6 k24s didn’t hit 30lbs till 5000rpm. I hope by not absolutely pushing this engine, it’s holds together and gives me a lot of easy miles. I’m excited to hear what you decide and see how your build goes. In my mind for twins the 550/660 route is the ultimate for this platform. Guess we will just have to wait and see!

[Imho]

Evalegacy I went the G25-550 route. I got tired of all the China hybrid turbo options out there. I really wanted to go XR770s but either finding those or upgrading 605 to those didn’t happen. I wanted quality turbos that are modern tech and that are sold everywhere, that’s where the G25-550/660 ect come in. I am going the 550 route because I’d rather sacrifice some top end to gain earlier spool. These things should have a fun power band. My SRM RS6 k24s didn’t hit 30lbs till 5000rpm. I hope by not absolutely pushing this engine, it’s holds together and gives me a lot of easy miles. I’m excited to hear what you decide and see how your build goes. In my mind for twins the 550/660 route is the ultimate for this platform. Guess we will just have to wait and see!

Spool on g25-550 is amazing here is example 4th gear run

[Blazius]

Alright that’s a option I did not know about. I believe this setup could be into the 850+ whp range with these turbos. But I don’t plan on running at those power level just due to longevity of the engine and drivetrain. I don’t mind spending the money on pistons at this point, I just want good parts and to do it correctly.

Brad will be doing my tuning once again, he does really awesome work. I can’t thank him enough. I’m very excited for the spring.

Engine parts off the top of my head
82 or 82.5mm pistons
IE H beams
Main studs/Vast girdle
Fluid damper

2.8 Heads & Cams
Supertech Inconel exhuast valves
Stock Intake valves
Supertech titanium springs and retainers
Headstuds

Well you have multiple options then regarding the pistons, since you looks like you are going for the overkill build anyway.
Also it is true Mahle will make customs pistons. Their alloy is one of the best, pistons you would find in crazy builds.

As for tuning if you want I can do speed density conversion on stock ecu if it dont work out with him, as you gonna be needing at this power level, and running on Alpha N (without maf) is not something I would advise.

[evalegacy]

I went the G25-550 route. I got tired of all the China hybrid turbo options out there. I really wanted to go XR770s but either finding those or upgrading 605 to those didn’t happen. I wanted quality turbos that are modern tech and that are sold everywhere, that’s where the G25-550/660 ect come in. I am going the 550 route because I’d rather sacrifice some top end to gain earlier spool. These things should have a fun power band. My SRM RS6 k24s didn’t hit 30lbs till 5000rpm. I hope by not absolutely pushing this engine, it’s holds together and gives me a lot of easy miles. I’m excited to hear what you decide and see how your build goes. In my mind for twins the 550/660 route is the ultimate for this platform. Guess we will just have to wait and see!

Exactly the same reasons I'm leaning towards the G25s as well. I would do XR770s in a heartbeat as you just can't beat the power for its simplicity, and long standing tested reliability. But as you stated, I'm finding them impossible to find even used. I found one store in Canada that sells non XR 770s but then I'd have to get them rebuilt. I thought K24s spooled quicker and could hit full boost by 4500, no? I also have a GT30 MK4 GTI so I'm no stranger to lag in spool time, which doesn't really bother me since most of my drives are on long country roads or the highway. I highly agree even with my power goals, I'd have to throw everything at this car and really push the engine to squeeze every bit of HP to get there with k24s and even then I'd be pushing them to their limit; I can much more easily make that power goal on G25s with more room to go further. I'm still trying to decide on 550s or 660s the shop I work with recommended 660s. I see plenty of numbers and graphs for 550s but barely anything out there on the 660s.

[Mocke]

Twin G25-660 IWG on a 3L RS motor from our customers.

837whp at 34psi. Initinal boost spoolup held back bc RR clutch slipped.

[waveblaster200]

Still trying to figure out pistons. I’m going to try call diamond again and see if this number off a pistons means anything. I’ll reach out to Mahle and see what they can offer.

[ubeermench]

I've been running stock pistons over 700whp for quite a while. Already forged as stock and can hold a bunch of power.

[waveblaster200]

Excellent yes stock pistons sound like great options, but I am already at 81.5mm and will have to bore it out further to get fresh cyl walls. Next stop would be 82/82.5/83mm

[Silverex]

For a high HP build I don’t think you’d want to go larger than 82mm to keep the walls as thick as possible.

[Monty23]

Excellent yes stock pistons sound like great options, but I am already at 81.5mm and will have to bore it out further to get fresh cyl walls. Next stop would be 82/82.5/83mm

I sent Diamond (Evan Booms was my contact) a stock piston to reverse engineer on October 21, 2021. So they have the stock piston geometry and should be able to use that to make you 82mm pistons. They made me a set of stroker pistons for my new engine.