Gwaihir
5+ Year Contributor
- 62
- 9
- Jun 18, 2018
-
CHELMSFORD,
Massachusetts
Reading through the threads about evo iii 16g. I've prepared my car for a tune (my profile is up to date) with new fuel system and all the other supporting mods needed to up the boost on my 16g past stock PSI of 12. My question is how do I know what I should be selecting as a target PSI for a tune?
I would like to think there is some math to the madness that can at least point me in the right direction. So below I have some rudimentary thoughts on how the PSI, turbo and fuel system relate. Let me know if I'm on the right track.
I know that flow rates of the turbo are piece in the puzzle and from what I have read in these threads:
https://www.dsmtuners.com/threads/the-difference-between-a-small-16g-and-a-big-16g.318980/
https://www.dsmtuners.com/threads/16g-flow-rates.375030/
https://www.dsmtuners.com/threads/evoiii-16g-lbs-min.208897/
15PSI on an evo 16g is going to be mid 20slbs/min. 20 PSI will start to show high 30s.
From this thread https://www.dsmtuners.com/threads/injectors-and-fuel-pumps.244522/ I found that 750 injectors at 80% are going to flow about 43lbs/min so I know that is my max limit I want to hit. Does PSI effect this at all or is PSI only going to impact the fuel pump?
My pump is currently without a rewire and according to the same injector/pump thread it looks like the Walbro 190 is going to support 43lbs/min of flow at 15PSI. I don't expect that my injectors would need to be open at 80% at this point though correct (due to the output of the 16g at 15PSI)? So I could go to a higher PSI, knowing the fuel pump will flow less than 43, but that will be ok because my injectors aren't near 80% DC and the turbo isn't close to flowing 43lbs/min yet?
20PSI shows the walbro 190 at about 38lbs/min. That should be in the ballpark of where the output of the evo 16g is at that PSI.
So based on maths (with the assumption that all the above makes sense) my max target for my fuel system without a rewire on the pump should be 20PSI? Do I need to back that off a bit to compensate for creep and maybe target 18PSI?
I'm running 93 Octane if that matters at all.
I would like to think there is some math to the madness that can at least point me in the right direction. So below I have some rudimentary thoughts on how the PSI, turbo and fuel system relate. Let me know if I'm on the right track.
I know that flow rates of the turbo are piece in the puzzle and from what I have read in these threads:
https://www.dsmtuners.com/threads/the-difference-between-a-small-16g-and-a-big-16g.318980/
https://www.dsmtuners.com/threads/16g-flow-rates.375030/
https://www.dsmtuners.com/threads/evoiii-16g-lbs-min.208897/
15PSI on an evo 16g is going to be mid 20slbs/min. 20 PSI will start to show high 30s.
From this thread https://www.dsmtuners.com/threads/injectors-and-fuel-pumps.244522/ I found that 750 injectors at 80% are going to flow about 43lbs/min so I know that is my max limit I want to hit. Does PSI effect this at all or is PSI only going to impact the fuel pump?
My pump is currently without a rewire and according to the same injector/pump thread it looks like the Walbro 190 is going to support 43lbs/min of flow at 15PSI. I don't expect that my injectors would need to be open at 80% at this point though correct (due to the output of the 16g at 15PSI)? So I could go to a higher PSI, knowing the fuel pump will flow less than 43, but that will be ok because my injectors aren't near 80% DC and the turbo isn't close to flowing 43lbs/min yet?
20PSI shows the walbro 190 at about 38lbs/min. That should be in the ballpark of where the output of the evo 16g is at that PSI.
So based on maths (with the assumption that all the above makes sense) my max target for my fuel system without a rewire on the pump should be 20PSI? Do I need to back that off a bit to compensate for creep and maybe target 18PSI?
I'm running 93 Octane if that matters at all.