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Message: [QUOTE="TARM, post: 354552, member: 578"] OK that makes much more sense. I was not sure how you were computing you ratios hence all the work above. I have noticed many people just subtract primary turbo boost from total boost and then do a standard PR formula to get PR and this is wrong. So you made the spring change on the secondary 66mm Comps gate. It was its boost that showed no change then not the primary turbos? So you have the secondary gate opening at a lower drive pressure and yet boost pressure did not change? There was no change to any of the boost levels ? Then it sounds like that size gate on that size turbine housing wheel size running at that low of a drive pressure is just too low. This is still the same exact issue just the gate that is past its limit has changed. You still IMO for a 50psi total boost have too little boost and drive pressure going thru that secondary turbo. That boost ratio is still, based on maps I could find for 66mm size turbos, not that good. I personally would really look at lowering the boost of the primary and upping the boost of the secondary. Still keep you at 50psi if that is what the goal is. Drop the Primary to a PR of 2.1 16 psi down from 25psi PR 2.7. That will allow you to flow more thru the Secondary and get it to a more efficient point in the map and will also get you back into a effective duty cycle for the secondary wg which it is not at the lower rate. This also still should keep the primary turbo in a 1:1 efficiency range as well. So I would flip flop what you were doing. See what spring it will take to get you to 16 psi boost. Why not go ahead and drop springs in the WG that gives you the min control: 15 secondary 8-10 primary gates. Plumb in both WGs top and bottom ports with boost. You get some balanced pressure on the valve which is suppose to help stabilize it from what I have read and then use a regulator on the top port to adjust gate opening pressure. Then you can easily play with PR and total boost drive:boost ratios without having to open up the WG and do spring swaps and wait and see. I personally would much rather just turn a couple knobs or levels than break open the gates. [/QUOTE]