What would be the ideal side seal clearance for a turbo motor ? its a small street port S5 13b and looking for around 300whp , would also like to know what size feed and return I could use as the car is stripped right now of fuel lines , for fuel rails I am using the S4 Turbo
Thanks

 

SS clearance is important to get just right. .002 is a good number.

most fuel rails hoses are dash 6 which is .34" I D.

 

.002 is what most shoot for but if you have a variance of .002-.003 between some of the side seals(1 being .002- the other being .005) you will be fine. While every seal is important the side seals are not near as important when it comes to compression as the apex seals and condition of rotor housings. Please keep this in context, Im not saying go run .020 clearance but it isnt as critical for all of them to be exact as a lot of "builders" would like you to believe.

 

the more consistent they are within the spec the better cold start up will be. For our engines that will be street driven we shoot for .002-.004. For the engines in our race cars we shoot for .004-.006". there are a lot of ppl that like to keep them tighter than that but its not worth having one bind and break.

 

I like .0015 thou (feeler slips without binding and can visually see side seal move left and right) for new seals but stick with the above suggested

thewird

 

Mazda Comp recommends .0039" to .0059".

Who to trust?

 

mazda comp is for race engines that will see high rpm and not worried about startup, dd, and fuel consumption. They set them loose so that at high rpm's they can "grow" and expand and not have any issues with binding and breaking.