rondofj Posted May 11, 2014 Author Share Posted May 11, 2014 Well that problem was there in the first full tune when I swapped to PowerFC from Nistune, I asked them to fix it this time, it was only a touch-up tune and 'massaging' it in this time after the exhaust fix, nothing major. Its definitely a 3-4sec major power drop with downshifting, sounds tune related aye? Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279058 Share on other sites More sharing options...
Ben C34 Posted May 11, 2014 Share Posted May 11, 2014 Well it's a result of the ecu doing something dumb, which it determines by how it is tuned. So yes, it is tune related. I would be cranking some more preload on the actuator. They wouldn't do it while tuning due to the heat around the manifold and turbo scaring them away, but letting it cool on the dyno to try it out would have been cheaper than another tune. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279067 Share on other sites More sharing options...
89CAL Posted May 11, 2014 Share Posted May 11, 2014 Seen as the problem wasnt there before and youve only improved the flow of exhaust gas leaving the turbo, then I'm not sure what else it would be? Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279068 Share on other sites More sharing options...
rondofj Posted May 11, 2014 Author Share Posted May 11, 2014 Thanks guys I will ask them to have a re-look, lesson learnt is that no matter how reputable the tuner, they never get it right in the first tune, not in my experience anyway Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279088 Share on other sites More sharing options...
Ben C34 Posted May 11, 2014 Share Posted May 11, 2014 Unless they do all the work and truly know the car. It's hardly their fault. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279096 Share on other sites More sharing options...
rondofj Posted May 11, 2014 Author Share Posted May 11, 2014 Its a 40mm wategate off housing, T boost controller so no actuator. I also dont see why its dropping 4psi up top now when before it was going from to 20-18 and 18-16 with the jem tune/nistune. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279099 Share on other sites More sharing options...
89CAL Posted May 11, 2014 Share Posted May 11, 2014 Do you have a boost controller? If not, what spring do you have in the wastegate? Only other thing could be the smaller turbine housing (maybe it needs a .8?), but I dont know alot about the precision turbos so I'm not even sure what size the turbo is lol. Anyway if no boost controller then that might improve it, if it alread has a boost controller then it might need some adjusting due to the change in exhaust flow Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279102 Share on other sites More sharing options...
XKLABA Posted May 11, 2014 Share Posted May 11, 2014 The external waste gate is you actuator ( its all in one unit ), I believe he said he has a T boost controller so its a bleed off setup, so the EBC will help to a point at both ends Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279110 Share on other sites More sharing options...
GTSBoy Posted May 11, 2014 Share Posted May 11, 2014 Boost drop is easily answered. Reduced back pressure in total means less restriction all the way back to the inlet and less boost required for a given amount of flow. Choke off the exhaust again and the back pressure will report back to the intake side at high revs again and Bob's your older male relative....less boost drop off at high flow. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279113 Share on other sites More sharing options...
rondofj Posted May 11, 2014 Author Share Posted May 11, 2014 Oh that explains it then..4psi drop is a bit much though.. Yes I have a turbosmart T controller off gate and other end connected to nipple in compressor housing, 18psi spring in wastegate so not lacking in that department. One nipple on the top of the gate is unconnected though? Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279117 Share on other sites More sharing options...
scotty nm35 Posted May 11, 2014 Share Posted May 11, 2014 With an ebc you can route boost to the top port to help hold the gate shut. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279135 Share on other sites More sharing options...
GTSBoy Posted May 11, 2014 Share Posted May 11, 2014 Yeah, a manual boost T type controller will never be able to stop the top end falling off if that's what the turbo wants to do. You need an EBC to take it by the scruff of the neck and force it to do what you want. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279207 Share on other sites More sharing options...
rondofj Posted May 11, 2014 Author Share Posted May 11, 2014 Cheers-mite be my next mod- will any ebay electronic boost controller like cheap china hdi do or only apexi avcr/ greedy profec spec 2 etc? Hope touch up tune wont be required as its already tuned to 22psi- Im about sick of all this tuning which isnt leading anywhere much.. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279347 Share on other sites More sharing options...
Ben C34 Posted May 11, 2014 Share Posted May 11, 2014 Gizmo have one for 290. I would look at that. A trader on here has then for that price delivered in the four sale section. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279399 Share on other sites More sharing options...
XKLABA Posted May 11, 2014 Share Posted May 11, 2014 The best and easiest EBC I have used is the HKS EVC 4 ( jap version ) 5 ( US version ), as with any thing car related " you get what you pay for " Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279400 Share on other sites More sharing options...
89CAL Posted May 11, 2014 Share Posted May 11, 2014 Yeah better way to do it, holding boost on top and bottom then bleeding the top pressure off. Id say the boost control is the issue with the boost tapering off up top but still doesnt explain the hesitation when downshifting Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279409 Share on other sites More sharing options...
hy_rpm Posted May 11, 2014 Share Posted May 11, 2014 How's your intake ? 3 inch all the way and free flowing as Tao from hypergear has tested at 250kw there is a difference of 13kw going from 2.5 inch intake to 3inch Also .63 rear housing may becoming at restriction on a 6cylinder and that power level and boost Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279479 Share on other sites More sharing options...
rondofj Posted May 11, 2014 Author Share Posted May 11, 2014 3" metal intake, 40mm gate, plumb back bov and plumb back screamer to 3" dump Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279489 Share on other sites More sharing options...
iruvyouskyrine Posted May 11, 2014 Share Posted May 11, 2014 #@rondofj trying to send you a PM but your inbox is full. Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279608 Share on other sites More sharing options...
hy_rpm Posted May 11, 2014 Share Posted May 11, 2014 Well can't be the intake then But might be good to search how much power people been getting using .63 with a rb25 Link to comment https://www.sau.com.au/forums/topic/440825-restriction-in-the-exhaust/page/6/#findComment-7279614 Share on other sites More sharing options...
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