Aftermarket pistons - stock CR or lower?

[m1tch]

Hi all,

Still researching into the various parts I will be looking to get at some point for my Project Autounion build, due to the engine power aim being at 520bhp I wanted to ask advice on compression ratio. I know that aftermarket pistons usually come with differing CR but wanted to ask if its worth getting pistons to create a lower CR for safety or is stock CR ok?

I guess I could simply look to get stock CR pistons and run a slightly thicker head gasket to lower the CR if there is less safety margin in the future. I do plan to run water/meth injection and would have the S4 injectors to ensure that the engine remains safe.

Just wondering what others have done, thinking stock CR is the most common route though.

 

[S3Alex]

Hi all,

Still researching into the various parts I will be looking to get at some point for my Project Autounion build, due to the engine power aim being at 520bhp I wanted to ask advice on compression ratio. I know that aftermarket pistons usually come with differing CR but wanted to ask if its worth getting pistons to create a lower CR for safety or is stock CR ok?

I guess I could simply look to get stock CR pistons and run a slightly thicker head gasket to lower the CR if there is less safety margin in the future. I do plan to run water/meth injection and would have the S4 injectors to ensure that the engine remains safe.

Just wondering what others have done, thinking stock CR is the most common route though.

Hi again....there are a pretty wide range of pistons out there...IE/JE/PEC/Wossner etc etc.

Mine are Wossner with a lower CR than stock,but advice does vary in terms of stock or lower CR,and my best advice would be to discuss it with your engine builder at the time.

 

[m1tch]

Hi again....there are a pretty wide range of pistons out there...IE/JE/PEC/Wossner etc etc.

Mine are Wossner with a lower CR than stock,but advice does vary in terms of stock or lower CR,and my best advice would be to discuss it with your engine builder at the time.

Hi again!

It will be myself who will be swapping out the pistons and rods, will however contact whoever I decide to remap and tune to car to see what they suggest, luckily I can still reduce the compression ratio with stock pistons by fitting the thicker head gasket.

 

[S3Alex]

Hi again!

It will be myself who will be swapping out the pistons and rods, will however contact whoever I decide to remap and tune to car to see what they suggest, luckily I can still reduce the compression ratio with stock pistons by fitting the thicker head gasket.

That's certainly going to be a cheaper route!

OK.....still as we've both agreed makes sense to involve the mapper,as different companies use different hardware,and different boost/timing settings which could make a big impact on this.
It may have given mine a bit of a safety margin during the early stages and the first build,but the whole engine is being stripped down and looked at again now,whilst Race Developments have some time to get on with the head work.

I would certainly recommend them for anything like that,and with 600bhp+ in mind,you're going to need the head worked on,plus they work closely with Storm,who dealt with all the Syvecs programming.