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  1. #1
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    3.6L S54 Technical Discussion

    The engineering involved with creating a 3.6L S54 fascinates me, and I'll explain why.

    The limits of displacement on the S54 block are defined by it's cylinder bore spacing, and also it's deck height. The former helps define the maximum bore size, and the latter helps define the maximum stroke. If you want more displacement, you've got to increase one, the other, or both.

    The S54 has a 91mm bore spacing, which is shared by most BMW inline 6 cylinder engines including the M50, S50, M52, S52, and M54 engine block families. The S54 block, made entirely of iron, has a bore size of 87mm leaving 4mm of material between cylinder bores. This isn't a lot of material to hold up to say 1000hp worth of cylinder pressure (2000+ PSI peak pressure) and excessive heat (Burn temperature is over 3000 degrees), so there are a couple of options available to help prepare a block for this kind of operating environment.

    The simplest method of increasing sealing capability between bores, from a work and cost perspective, is to o-ring the block to provide a ring around the cylinder bore to help contain pressure. Generally, you can run an o-ring on as small a gap between cylinders as 2.5mm, so the OEM S54 block is well within limits at 4mm.

    Another option is to have the block sleeved with a set of cylinder liners which gives a wide range of options with regard to cylinder bore. The number one reason why professional race teams these days are sleeving cylinder blocks is to provide a uniform material for special coatings to be applied to. These coatings are designed to be applied to specific alloys....and most blocks aren't made of these alloys. Anyway...back to the bore size: A smaller bore size by sleeving the block can increase the gap between cylinder bores providing better pressure handling.

    A 3rd option which is very rarely used is to run a cylinder liner into the block that protrudes above the deck height into a recess that's cut into the cylinder head. There is literally a solid coupling between the cylinder liner and the cylinder head.

    For the ultimate 3.6L S54, I would chose to sleeve the block, and reduce the cylinder bore slightly to 86mm to give increased block strength.

    There's also the issue of how close the cylinder bore is to the valves (Shrouding), which is why I wouldn't want to reduce the bore size very much from the OEM sizing.

    Next up: Stroke
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    Good post Adam as usual.
    This is where Mert @Twinturbom3 should come and give us some info about his engine. Mert, if you want to achieve some respect for yourself, this is an opportunity man.

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    Adam, glad to see you posting about this. You must have seen my comments earlier. Hopefully you can answer some of the questions that have been going around in my head.

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    I had the pleasure to work on a assembly of Stroked Hartge 3.5l based on the S50 3.0 motor. Their method was slightly bored pistons (86.4 if I can recall) with stock rods and decked block. The deck was 10mm think and required the block to be sleeved. The block also needed to be machined to make room for the larger stroke of the crank. The timing change was also extended.
    The engine worked well at low rpm but use to have harmonic vibrations at high rpm. Over 8000rpm the knock sensor would hear this vibration as knock.

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    Adam,

    Very good discussion. Thank you for starting this thread, it will raise the S54 bar.

    3600 cc entails more than rods and pistons and bore diameter. I am not talking about a N/A 3.6L. Its a twin turbocharged and nitroused S54. There are many parts that need to be produced from scratch. Even the smallest bolt/screw must be up to its task in terms of tensile strength and hardness. I call these " the details" that make an engine work.

    All the work I have done on my own S54s is propritary and I wont share them. They are unique for me.
    E36 M3 Euro TT 60-130 mph 4.49 s
    E46 M3 3.6L TT 60-130 mph 4.22 s
    All Wheel drive M3 Twin Turbo
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    This is where things get really interesting.

    Below is a range of Bore and Stroke combinations that would be required to hit 3.6L:

    87.5mm Bore X 99.8mm Stroke
    87.0mm Bore X 100.9mm Stroke
    86.5mm Bore X 102.1mm Stroke
    86.0mm Bore X 103.3mm Stroke
    85.5mm Bore X 104.5mm Stroke

    So with my chosen 86mm Bore, I would need to fit 103mm of stroke into the block. As a reminder, the OEM S54 crank has 91mm of stroke, so we're looking to increase effective stroke by a full 12mm. (Or from 9 - 13.5mm depending on our bore configuration)

    What's so interesting about the stroke? Block geometry, or more specifically the fact that the S54 block has a deck height of 216.9mm

    About 1.5 years ago, I went through the design process with a set of custom pistons to make over 1000hp. Some of you may be familiar with this as I posted about it previously, and the resultant pistons and DLC coated wrist pins. From that process I learned a lot about what you needed to stack above the wrist pin to make that power and have the piston survive.

    Here's a summary of this "stack":

    Top Ring Land - 10mm
    Top Ring - 1.5mm
    Middle Ring Land - 3mm
    Middle Ring - 1.2mm
    Bottom Ring Land - 2mm
    Oil Ring - 2.5mm
    Wrist pin radius - 11mm
    Wrist pin support - 4mm

    Compression Height = 31.2mm

    I guess I should explain "deck height", and "compression height" so that everyone can follow where I'm going with this. Deck height is the distance from the top of the block to the center-line of the crank, or where the main caps attach to the block. You need to be able to fit the piston, rod, and crank stroke into the space, or the engine just won't work. Compression height is the distance from the center of the wrist pin, to the top of the piston.

    So if we put the piston into the bore, the bottom edge of the piston under the wrist pin would sit 46.2mm (CH=31.2+11+4) below the deck of the block. The piston skirt does sit a little lower than this normally (4-10mm depending on the design) but it isn't in a critical clearance area that could hit the crank.

    Here's a very visual example of the movement that occurs in the S54 block, but with an 84.5mm bore and 89.6mm stroke:

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Click here to enlarge

    Those of you doing the math would find we've got 170.7mm of block left to work with, so lets continue with the measurements.

    On any rod journal, you need approximately 3mm of material on the side of the journal to support/center the bearing and rod assembly. Some cranks have more, but this crank needs all the space it can get, so we'll stick with this minimum number. This means that the actual height of the crank will be 3mm higher than half of the stroke (103.3mm) plus the journal radius (44mm rod journals are used on almost all 6 Cylinder BMW engines) which is 76.65mm. (51.65mm+22mm+3mm) This also means that the top of the crank will sit 140.25mm below the deck of the block.

    So with our piston at TDC, and our crank at the top of it's rotation, we find the following:

    - The center of wrist pin is 31.2mm below the deck of the block.
    - The center of the rod journal is 165.25mm below the deck of the block. (216.9 - (103.3/2) = 165.25)
    - The distance between the wrist pin center and the rod journal center is 134.05mm.

    So we've just defined our rod length with a 216.9mm deck height, and 103.3mm stroke to be 134.05mm. If it was any longer, the piston would smash against the cylinder head at TDC.

    For reference, the OEM rod length on the S54 is 139mm.

    Now...lets move the piston down 103.3mm into the block. At this point, the bottom of the piston is sitting 103.3mm + 46.2mm (height of piston assembly) below the deck of the block, or 149.5mm below the deck of the block.

    As you can see, we have a clearance issue where the piston would sit 9.25mm lower than the top of the crank. Or in other words, the piston would have hit the top of the crank before reaching BDC.

    Looks like we're back to the drawing board!
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    Click here to enlarge Originally Posted by Sorena Click here to enlarge
    Good post Adam as usual.
    This is where Mert @Twinturbom3 should come and give us some info about his engine. Mert, if you want to achieve some respect for yourself, this is an opportunity man.
    Thanks! Thought it was time to re-direct things.

    Click here to enlarge Originally Posted by metrik Click here to enlarge
    Adam, glad to see you posting about this. You must have seen my comments earlier. Hopefully you can answer some of the questions that have been going around in my head.
    Actually I hadn't seen your comments, but I'm glad that other people have been thinking about this.

    Click here to enlarge Originally Posted by George Smooth Click here to enlarge
    I had the pleasure to work on a assembly of Stroked Hartge 3.5l based on the S50 3.0 motor. Their method was slightly bored pistons (86.4 if I can recall) with stock rods and decked block. The deck was 10mm think and required the block to be sleeved. The block also needed to be machined to make room for the larger stroke of the crank. The timing change was also extended.
    The engine worked well at low rpm but use to have harmonic vibrations at high rpm. Over 8000rpm the knock sensor would hear this vibration as knock.
    Very cool info! As you can see by my second post....most blocks will need a little help to make this work.

    Click here to enlarge Originally Posted by Twinturbom3 Click here to enlarge
    Adam,

    Very good discussion. Thank you for starting this thread, it will raise the S54 bar.

    3600 cc entails more than rods and pistons and bore diameter. I am not talking about a N/A 3.6L. Its a twin turbocharged and nitroused S54. There are many parts that need to be produced from scratch. Even the smallest bolt/screw must be up to its task in terms of tensile strength and hardness. I call these " the details" that make an engine work.

    All the work I have done on my own S54s is propritary and I wont share them. They are unique for me.
    Mert,

    I'd be happy for you to confirm if I'm right or wrong when I arrive at a parameter by reason of logic and deduction. I know what it takes to go through some of this process, so I understand being protective of what has come at great cost to you. But like some F1 journalists do, we can take an educated guess....
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    I went up to an 88mm bore, which is as far as I'd want to go on a 91mm bore spacing, and a 98.6mm stroke, and I still came up with 2.2mm of interference.

    That leaves 2 options: The rod bearing journal has been reduced in size,(Not a good idea with big power) or a spacer has been added to the deck along with sleeves as George Smooth mentioned.

    So I believe we have a block with a spacer at least 9.25mm thick on it to achieve a stroke of 103.3mm. Also, the rods are most likely to be in the 143.3+mm area.

    My next question is: How was the block clearanced without hitting the oil gallery?

    Click here to enlarge

    Of note: That's not an S54 block and crank, but it illustrates my point. The oil gallery is located in the same place on the S54 block.
    Last edited by PEI330Ci; 08-29-2011 at 04:42 PM. Reason: Type on stroke mm
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    you are quite the fountain of knowledge PEI, thank you for this informative post. its doubtful mert will share any of his findings/research but what you have shown here is almost just as good, in a different way of course. as always i look forward to your future posts here, you never cease to impress me.
    Click here to enlarge
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    Adam,

    On this entire forum and on other bmw related forums I ve seen one person who takes care of all the details. Who does it with passion and by a lot of research. Its you.

    However, as I stated on my private message I will "not" share any information. Its private for me and will be kept private as well. I dont do it for money, its due to passion. Can you imagine a 4,49 s 60-130 mph is not enough for someone. Thats me.
    E36 M3 Euro TT 60-130 mph 4.49 s
    E46 M3 3.6L TT 60-130 mph 4.22 s
    All Wheel drive M3 Twin Turbo
    997 TT



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    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    This is where things get really interesting.

    Below is a range of Bore and Stroke combinations that would be required to hit 3.6L:

    87.5mm Bore X 99.8mm Stroke
    87.0mm Bore X 100.9mm Stroke
    86.5mm Bore X 102.1mm Stroke
    86.0mm Bore X 103.3mm Stroke
    85.5mm Bore X 104.5mm Stroke

    So with my chosen 86mm Bore, I would need to fit 103mm of stroke into the block. As a reminder, the OEM S54 crank has 91mm of stroke, so we're looking to increase effective stroke by a full 12mm. (Or from 9 - 13.5mm depending on our bore configuration)

    What's so interesting about the stroke? Block geometry, or more specifically the fact that the S54 block has a deck height of 216.9mm

    About 1.5 years ago, I went through the design process with a set of custom pistons to make over 1000hp. Some of you may be familiar with this as I posted about it previously, and the resultant pistons and DLC coated wrist pins. From that process I learned a lot about what you needed to stack above the wrist pin to make that power and have the piston survive.

    Here's a summary of this "stack":

    Top Ring Land - 10mm
    Top Ring - 1.5mm
    Middle Ring Land - 3mm
    Middle Ring - 1.2mm
    Bottom Ring Land - 2mm
    Oil Ring - 2.5mm
    Wrist pin radius - 11mm
    Wrist pin support - 4mm

    Compression Height = 31.2mm

    I guess I should explain "deck height", and "compression height" so that everyone can follow where I'm going with this. Deck height is the distance from the top of the block to the center-line of the crank, or where the main caps attach to the block. You need to be able to fit the piston, rod, and crank stroke into the space, or the engine just won't work. Compression height is the distance from the center of the wrist pin, to the top of the piston.

    So if we put the piston into the bore, the bottom edge of the piston under the wrist pin would sit 46.2mm (CH=31.2+11+4) below the deck of the block. The piston skirt does sit a little lower than this normally (4-10mm depending on the design) but it isn't in a critical clearance area that could hit the crank.

    Here's a very visual example of the movement that occurs in the S54 block, but with an 84.5mm bore and 89.6mm stroke:

    http://www.audiboost.com/images/impo...ry201010-1.jpg

    http://www.audiboost.com/images/impo...ry201011-1.jpg

    http://www.audiboost.com/images/impo...ry201013-1.jpg

    http://www.audiboost.com/images/impo...ry201014-1.jpg

    http://www.audiboost.com/images/impo...ry201015-1.jpg

    http://www.audiboost.com/images/impo...ry201017-1.jpg

    Those of you doing the math would find we've got 170.7mm of block left to work with, so lets continue with the measurements.

    On any rod journal, you need approximately 3mm of material on the side of the journal to support/center the bearing and rod assembly. Some cranks have more, but this crank needs all the space it can get, so we'll stick with this minimum number. This means that the actual height of the crank will be 3mm higher than half of the stroke (103.3mm) plus the journal radius (44mm rod journals are used on almost all 6 Cylinder BMW engines) which is 76.65mm. (51.65mm+22mm+3mm) This also means that the top of the crank will sit 140.25mm below the deck of the block.

    So with our piston at TDC, and our crank at the top of it's rotation, we find the following:

    - The center of wrist pin is 31.2mm below the deck of the block.
    - The center of the rod journal is 165.25mm below the deck of the block. (216.9 - (103.3/2) = 165.25)
    - The distance between the wrist pin center and the rod journal center is 134.05mm.

    So we've just defined our rod length with a 216.9mm deck height, and 103.3mm stroke to be 134.05mm. If it was any longer, the piston would smash against the cylinder head at TDC.

    For reference, the OEM rod length on the S54 is 139mm.

    Now...lets move the piston down 103.3mm into the block. At this point, the bottom of the piston is sitting 103.3mm + 46.2mm (height of piston assembly) below the deck of the block, or 149.5mm below the deck of the block.

    As you can see, we have a clearance issue where the piston would sit 9.25mm lower than the top of the crank. Or in other words, the piston would have hit the top of the crank before reaching BDC.

    Looks like we're back to the drawing board!
    wow man, wow! the info you have is much more than most tuners man, this forum should be proud to have you.

  12. #12
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    Click here to enlarge Originally Posted by oddjob2021 Click here to enlarge
    you are quite the fountain of knowledge PEI, thank you for this informative post. its doubtful mert will share any of his findings/research but what you have shown here is almost just as good, in a different way of course. as always i look forward to your future posts here, you never cease to impress me.
    Thanks.

    My info comes from a range of reliable sources, and I always welcome people with a fresh point of view or a different approach.

    As odd as it sounds, I'm eagerly awaiting your next dyno session to see what those "new" turbos did.

    Click here to enlarge Originally Posted by Twinturbom3 Click here to enlarge
    Adam,

    On this entire forum and on other bmw related forums I ve seen one person who takes care of all the details. Who does it with passion and by a lot of research. Its you.

    However, as I stated on my private message I will "not" share any information. Its private for me and will be kept private as well. I dont do it for money, its due to passion. Can you imagine a 4,49 s 60-130 mph is not enough for someone. Thats me.
    Mert,

    Thank you for the kind compliment.

    Eid Mubarak!

    Off to bed...I've got to be up in a couple of hours.
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    Adam,

    thank you very much. Good night.
    E36 M3 Euro TT 60-130 mph 4.49 s
    E46 M3 3.6L TT 60-130 mph 4.22 s
    All Wheel drive M3 Twin Turbo
    997 TT



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    Click here to enlarge Originally Posted by Twinturbom3 Click here to enlarge
    However, as I stated on my private message I will "not" share any information. Its private for me and will be kept private as well. I dont do it for money, its due to passion. Can you imagine a 4,49 s 60-130 mph is not enough for someone. Thats me.
    Mert, please don't downgrade this thread with 60-130 $#@!. I'm full of it, and also this much close to neg rep you which almost bans you. You don't want to share your info? that's ok, it's your personal info. However this is true for others too, you can't expect others come and share their info with you such as their 60-130 time.

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    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    So I believe we have a block with a spacer at least 9.25mm thick on it to achieve a stroke of 103.3mm. Also, the rods are most likely to be in the 143.3+mm area.
    It didn't even occur to me to look at deck height. My concerns were about the 20% increase in piston speeds that would come from a 101mm stroke, but it looks like it is even complicated than that.

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    Click here to enlarge Originally Posted by Sorena Click here to enlarge
    Mert, please don't downgrade this thread with 60-130 $#@!. I'm full of it, and also this much close to neg rep you which almost bans you. You don't want to share your info? that's ok, it's your personal info. However this is true for others too, you can't expect others come and share their info with you such as their 60-130 time.
    AMEN!

    i owe you a positive rep, i must spread it around first though...lol
    Click here to enlarge Originally Posted by TwinturboM3
    I bang the chickens on my farm 60-130 times a day.
    Click here to enlarge

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    Wow. This is an amazing thread. Thanks so much for sharing your knowledge. This is really cool stuff!

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    crazy info about the s54 and the options.
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    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    This is where things get really interesting.

    Below is a range of Bore and Stroke combinations that would be required to hit 3.6L:

    87.5mm Bore X 99.8mm Stroke
    87.0mm Bore X 100.9mm Stroke
    86.5mm Bore X 102.1mm Stroke
    86.0mm Bore X 103.3mm Stroke
    85.5mm Bore X 104.5mm Stroke

    So with my chosen 86mm Bore, I would need to fit 103mm of stroke into the block. As a reminder, the OEM S54 crank has 91mm of stroke, so we're looking to increase effective stroke by a full 12mm. (Or from 9 - 13.5mm depending on our bore configuration)

    What's so interesting about the stroke? Block geometry, or more specifically the fact that the S54 block has a deck height of 216.9mm

    About 1.5 years ago, I went through the design process with a set of custom pistons to make over 1000hp. Some of you may be familiar with this as I posted about it previously, and the resultant pistons and DLC coated wrist pins. From that process I learned a lot about what you needed to stack above the wrist pin to make that power and have the piston survive.

    Here's a summary of this "stack":

    Top Ring Land - 10mm
    Top Ring - 1.5mm
    Middle Ring Land - 3mm
    Middle Ring - 1.2mm
    Bottom Ring Land - 2mm
    Oil Ring - 2.5mm
    Wrist pin radius - 11mm
    Wrist pin support - 4mm

    Compression Height = 31.2mm

    I guess I should explain "deck height", and "compression height" so that everyone can follow where I'm going with this. Deck height is the distance from the top of the block to the center-line of the crank, or where the main caps attach to the block. You need to be able to fit the piston, rod, and crank stroke into the space, or the engine just won't work. Compression height is the distance from the center of the wrist pin, to the top of the piston.

    So if we put the piston into the bore, the bottom edge of the piston under the wrist pin would sit 46.2mm (CH=31.2+11+4) below the deck of the block. The piston skirt does sit a little lower than this normally (4-10mm depending on the design) but it isn't in a critical clearance area that could hit the crank.

    Here's a very visual example of the movement that occurs in the S54 block, but with an 84.5mm bore and 89.6mm stroke:

    http://www.audiboost.com/images/impo...ry201010-1.jpg

    http://www.audiboost.com/images/impo...ry201011-1.jpg

    http://www.audiboost.com/images/impo...ry201013-1.jpg

    http://www.audiboost.com/images/impo...ry201014-1.jpg

    http://www.audiboost.com/images/impo...ry201015-1.jpg

    http://www.audiboost.com/images/impo...ry201017-1.jpg

    Those of you doing the math would find we've got 170.7mm of block left to work with, so lets continue with the measurements.

    On any rod journal, you need approximately 3mm of material on the side of the journal to support/center the bearing and rod assembly. Some cranks have more, but this crank needs all the space it can get, so we'll stick with this minimum number. This means that the actual height of the crank will be 3mm higher than half of the stroke (103.3mm) plus the journal radius (44mm rod journals are used on almost all 6 Cylinder BMW engines) which is 76.65mm. (51.65mm+22mm+3mm) This also means that the top of the crank will sit 140.25mm below the deck of the block.

    So with our piston at TDC, and our crank at the top of it's rotation, we find the following:

    - The center of wrist pin is 31.2mm below the deck of the block.
    - The center of the rod journal is 165.25mm below the deck of the block. (216.9 - (103.3/2) = 165.25)
    - The distance between the wrist pin center and the rod journal center is 134.05mm.

    So we've just defined our rod length with a 216.9mm deck height, and 103.3mm stroke to be 134.05mm. If it was any longer, the piston would smash against the cylinder head at TDC.

    For reference, the OEM rod length on the S54 is 139mm.

    Now...lets move the piston down 103.3mm into the block. At this point, the bottom of the piston is sitting 103.3mm + 46.2mm (height of piston assembly) below the deck of the block, or 149.5mm below the deck of the block.

    As you can see, we have a clearance issue where the piston would sit 9.25mm lower than the top of the crank. Or in other words, the piston would have hit the top of the crank before reaching BDC.

    Looks like we're back to the drawing board!
    This is getting very, very good.

  20. #20
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    Click here to enlarge Originally Posted by Sorena Click here to enlarge
    wow man, wow! the info you have is much more than most tuners man, this forum should be proud to have you.
    Of course, very proud.

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    Gents,

    I'm afraid I used the wrong # for the rod journal size, so the numbers above are slightly off. The correct size of the OEM rod journal is 49mm.

    This actually increase the area of contact from 9.25mm up to 11.75mm on our theoretical 103.3mm stroke engine.

    I think everyone gets the point though, this isn't an easy engine to build......
    Rep Points > Posts since 2010

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    1 out of 1 members liked this post. Yes Reputation No
    Click here to enlarge Originally Posted by PEI330Ci Click here to enlarge
    Gents,

    I'm afraid I used the wrong # for the rod journal size, so the numbers above are slightly off. The correct size of the OEM rod journal is 49mm.

    This actually increase the area of contact from 9.25mm up to 11.75mm on our theoretical 103.3mm stroke engine.

    I think everyone gets the point though, this isn't an easy engine to build......
    Aww damn, your numbers were wrong! And I was planning to build this in my backyard lol jk jk. No problem dude. thanks for the update!
    Burger Motorsports
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  23. #23
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    Hey Adam,
    some reading on spacer plates on nissan RB engines, if it helps:

    http://www.gtr.co.uk/forum/151632-spacer-plates-3.html

    http://www.skylinesaustralia.com/for...r-more-torque/

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    I'd like to have a 3.6L N/A built motor in an E30 or E36 with a very large carbon airbox. 450whp N/A would be gods gift to driving pleasure and you'd probably annihilate many boosted cars, especially if the rear tires were the same

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    Sub'd!!

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