Raising compression and XFI

[WSLN 6]

If I get the receiver grooves machined off of my GN1's, how will the increased compression affect my tune with XFI? Would I back off the whole timing table a little?
Cal? :smile:

 

[HighPSI]

It won't effect it that much. If your running pump gas, I would pull a couple of degrees of timing out to be safe, then sneak back up on it.

 

[Dusty Bradford]

If I get the receiver grooves machined off of my GN1's, how will the increased compression affect my tune with XFI? Would I back off the whole timing table a little?
Cal? :smile:

I'd check the depth of the groove before I did anything else. You want to keep as much deck thickness as you can. Some local guys have put wire in the grooves and decked the wire so the head doesn't loose any thickness. Just cutting the deck can cause other issues with the pushrod length as well if you don't have adjustable rockers.

If you decide to cut the grooves off you can have the shop cc the chamber, before and after. Then use some of the online calculators to figure the compression change.

 

[WSLN 6]

Time was a factor on this one...the heads are milled flat now, I have adjustable T&D's with enough adjustment to keep the oiling holes present with the longer perceived pushrods.
If only our race season was more than 3 months long....:smile: