I have an update on this thread. I know it's old but when I ran into it about a year or so ago it was the post by the self-described 'newbie' 'Humour' that caught my attention. I'll apologize in advance because this is bound to be a pretty long story.
My M52B28 (aluminum) was beginning to tire after long miles and lots of track time. I decided I would build a new one. Then I ran across this thread I'm posting in currently, and another in the forum: (https://www.r3vlimited.com/board/for...troker-options) Needless to say, I was infatuated with the thought of messing around with this stuff. I figured I'd take 'Humour's hypothesis and prove it out because I just couldn't sleep just constantly going over it and over it in my head.
I was a little familiar with the M50B25TU because I'd built one for an endurance race car. I was really impressed with the stoutness of the forged connecting rods in that engine. WAY more beefy than the ones in the stock M52. AND longer. I liked the idea of improving the rod ratio for better, sustained top-end performance at the track. I wanted to find a way to use those rods in some other application. SO I picked up a used set of M50B25TU pistons and connecting rods for a couple hondo, then bought a similar set from a M54B30. I put the M54 pistons on the M50TU connecting rods and dropped them in the block with the M52B28 crank (I'll summarize the numbers below). I was delighted to find the math worked out and they were roughly 0.013" (0.32mm) above deck! Cool. So I continued the build and moved ahead with the decision to purchase some forged pistons (info below) and go for around 11:1 measured CR so I could use it with premium without fear of detonation.
I'll include some pix as I took a bunch but for this post I'll dump in the numbers I got from my measurements. Here's a list of parts and measurements:
The short story is it fired right up. Like faster than any engine I'd ever built. I was shocked!! AND no impending sound of bashing parts! Very exciting. Spent a month breaking it in and then really pounded it. OMG! IT's Amazing. The SOUND!
This is all the data I found and physically measured. I built this engine and held off on adding this post until it was broken in and thrashed around a bit to prove it worked. Hope this was interesting for everyone!
In summary, there's no getting around needing forged pistons for higher compression ratios IMO. That said, It would be pretty damn cool to do a budget build with this and literally use M50TU rods with stock M54 pistons in this block and tune the CR with the MLS gasket. 12.5:1 is easy (still wouldn't have the balls, personally, to try this without forged pistons). Maybe E85? I hope there's other dorks like me interested in this stuff. Maybe I'll put my vids on YouTube and link it here.
I'll follow up with pix and component weights and shit if people are interested.
My M52B28 (aluminum) was beginning to tire after long miles and lots of track time. I decided I would build a new one. Then I ran across this thread I'm posting in currently, and another in the forum: (https://www.r3vlimited.com/board/for...troker-options) Needless to say, I was infatuated with the thought of messing around with this stuff. I figured I'd take 'Humour's hypothesis and prove it out because I just couldn't sleep just constantly going over it and over it in my head.
I was a little familiar with the M50B25TU because I'd built one for an endurance race car. I was really impressed with the stoutness of the forged connecting rods in that engine. WAY more beefy than the ones in the stock M52. AND longer. I liked the idea of improving the rod ratio for better, sustained top-end performance at the track. I wanted to find a way to use those rods in some other application. SO I picked up a used set of M50B25TU pistons and connecting rods for a couple hondo, then bought a similar set from a M54B30. I put the M54 pistons on the M50TU connecting rods and dropped them in the block with the M52B28 crank (I'll summarize the numbers below). I was delighted to find the math worked out and they were roughly 0.013" (0.32mm) above deck! Cool. So I continued the build and moved ahead with the decision to purchase some forged pistons (info below) and go for around 11:1 measured CR so I could use it with premium without fear of detonation.
I'll include some pix as I took a bunch but for this post I'll dump in the numbers I got from my measurements. Here's a list of parts and measurements:
- M52B28 stroke = 84mm
- M50B25TU stroke = 75mm
- M50B25TU connecting rod length = 140mm
- M52B28 connecting rod length = 135mm
- M54B30 piston height = 28.32mm
- M52B28 piston height = 31.82mm
- M50B25TU deckheight = 210.7mm
- M52B28 deckheight = 209.98mm
- Wiseco pistons bore size = 84.5mm
- Cometic MLS head gasket thickness = 0.056"
- Cometic MLS head gasket bore opening = 85mm
- M52B28 cylinder head chamber volume = 34cc
- Wiseco piston dish volume = -7.3cc
- Calculated compression ratio = 11.08:1
- Wiseco pistons: WKE325M845
These pistons are 84.5mm and have a 7.3cc dish for forced induction applications using the M54B30. - Cometic MLS: C4328-056
This is .056 (1.42mm) thick MLS gasket. 85mm bore.
The short story is it fired right up. Like faster than any engine I'd ever built. I was shocked!! AND no impending sound of bashing parts! Very exciting. Spent a month breaking it in and then really pounded it. OMG! IT's Amazing. The SOUND!
This is all the data I found and physically measured. I built this engine and held off on adding this post until it was broken in and thrashed around a bit to prove it worked. Hope this was interesting for everyone!
In summary, there's no getting around needing forged pistons for higher compression ratios IMO. That said, It would be pretty damn cool to do a budget build with this and literally use M50TU rods with stock M54 pistons in this block and tune the CR with the MLS gasket. 12.5:1 is easy (still wouldn't have the balls, personally, to try this without forged pistons). Maybe E85? I hope there's other dorks like me interested in this stuff. Maybe I'll put my vids on YouTube and link it here.
I'll follow up with pix and component weights and shit if people are interested.
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