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Discussion Starter · #1 ·
I am in the process of finishing up a turbo mkv R32 build (HPA 7670 with a custom front mount intercooler). During this whole process, lowering the compression ratio is necessary while adding any type of boost to the motor to run the car safely and there is some misinformation I am trying to sort through regarding head spacers/ spacer gaskets for my build. So, HPA sent me a 5mm head spacer (the spacer is 5mm, not including the thickness of 2 head gaskets required to seal the head with the spacer. Each gasket's compressed thickness is supposedly .065") and this is supposed to lower the compression to 7:1, which I suspected was way too low for my power goal of being 400-500 awhp. Fred at united motorsport confirmed this being too low as well, and said the timing would be whacky while trying to tune this thing, and not to install it. Any ways, I found a company called SPA that sells a 3.65mm spacer head gasket thats supposed to lower the compression to 8.5:1. Here's the kicker: MK4 and Mk5 R32's have different compression ratio's, mk4's being 11.25:1 and mk5's being 10.85:1. So SPA, or any of these companies selling head spacers or spacer gaskets do not list the specified compression reduction for mk4 and mk5 models. Does anybody know what size spacers/head gaskets achieve what compression ratio for each year r32 engine? And what is the difference between mk4 and mk5 r32's difference in CR (pistons possibly?). The biggest issue Im having is if SPA advertised their 3.65mm headgasket for an mk4 engine (11.25:1CR) bringing it down to 8.5:1, this means me using that gasket on my 10.85:1 CR mk5 engine is resulting in an even lower CR than 8.5:1, and Im not sure if I want it that low. Any knowledge on this subject is appreciated!
 

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There's a group on Facebook "Everything VR6 Turbo & S/C" that would be your best bet for getting help. Tons of people there with experience


I am in the process of finishing up a turbo mkv R32 build (HPA 7670 with a custom front mount intercooler). During this whole process, lowering the compression ratio is necessary while adding any type of boost to the motor to run the car safely and there is some misinformation I am trying to sort through regarding head spacers/ spacer gaskets for my build. So, HPA sent me a 5mm head spacer (the spacer is 5mm, not including the thickness of 2 head gaskets required to seal the head with the spacer. Each gasket's compressed thickness is supposedly .065") and this is supposed to lower the compression to 7:1, which I suspected was way too low for my power goal of being 400-500 awhp. Fred at united motorsport confirmed this being too low as well, and said the timing would be whacky while trying to tune this thing, and not to install it. Any ways, I found a company called SPA that sells a 3.65mm spacer head gasket thats supposed to lower the compression to 8.5:1. Here's the kicker: MK4 and Mk5 R32's have different compression ratio's, mk4's being 11.25:1 and mk5's being 10.85:1. So SPA, or any of these companies selling head spacers or spacer gaskets do not list the specified compression reduction for mk4 and mk5 models. Does anybody know what size spacers/head gaskets achieve what compression ratio for each year r32 engine? And what is the difference between mk4 and mk5 r32's difference in CR (pistons possibly?). The biggest issue Im having is if SPA advertised their 3.65mm headgasket for an mk4 engine (11.25:1CR) bringing it down to 8.5:1, this means me using that gasket on my 10.85:1 CR mk5 engine is resulting in an even lower CR than 8.5:1, and Im not sure if I want it that low. Any knowledge on this subject is appreciated!
 

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Discussion Starter · #3 ·
Thanks Leo, Im aware of the page. You told me about this a week or two ago…. Been blowing that page up a lot and wanted to post on here to switch it up a little. Thanks
 
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