Turbo surge on FPGreen or 20Gs
#3
Evolved Member
iTrader: (20)
Join Date: May 2007
Location: houston
Posts: 660
Likes: 0
Received 0 Likes
on
0 Posts
im getting big time surge w/ my FPgreen when i floor it at WOT on full boost at 25psi. It sounds like BOV flutter but constant while im in boost... then slightly goes away in the upper rpm range. Its an issue we HOPE to remedy tonight by cutting off my HKS BOV and welding on a vband TIAL bov.
#4
Thats what I though based on some flow maps I made using a 20G efficiency plot. This would be even worse on a stock cam evo due to volumetric efficiency. I will plot my maps later. After 4K RPMs it looks good (at around 22 psi) but from 3 to 4K it appears that it will surge if the turbine has enought time and flow to build high boost, which can be done while in load in high gears.
Last edited by racer135; Mar 26, 2009 at 06:36 PM.
#5
Evolving Member
Join Date: Aug 2008
Location: dallas
Posts: 131
Likes: 0
Received 0 Likes
on
0 Posts
i have a fp white turbo and i run 24 psi and when i am in 4th or 5th gear at low rpms and i floor it to get around some one it surges, some one told me tht it might be my bov, i have the greddy type rs and heard it leaks
#7
Evolved Member
iTrader: (36)
When I first got my Green it did the same thing at low rpm, high gear acceleration.
At first, I just stepped on the gas more and it helped a bit, but not fully.
I found dropping a gear or two works much better.
It likes the higher rpm's much better. (4-6k rpm).
Just my .02..
It was more of driving style then anything else..
I will say, that now that i have the RED, it does not do it as much, but still does it, if i try to.
So I dont, I just drop a gear and BAM, gone.....
good luck...
At first, I just stepped on the gas more and it helped a bit, but not fully.
I found dropping a gear or two works much better.
It likes the higher rpm's much better. (4-6k rpm).
Just my .02..
It was more of driving style then anything else..
I will say, that now that i have the RED, it does not do it as much, but still does it, if i try to.
So I dont, I just drop a gear and BAM, gone.....
good luck...
Trending Topics
#8
Based on the plots I made it should be the turbo. A weak DV will help too but the DV capacity is independent of rpms. Engine flow and it capacity to "swalow" the turbo airflow increases with rpms thats why you will not see it at high rpms unless you have a huge turbo.
#10
Evolved Member
iTrader: (135)
Join Date: Jan 2007
Location: Indianapolis
Posts: 1,433
Likes: 0
Received 0 Likes
on
0 Posts
im getting big time surge w/ my FPgreen when i floor it at WOT on full boost at 25psi. It sounds like BOV flutter but constant while im in boost... then slightly goes away in the upper rpm range. Its an issue we HOPE to remedy tonight by cutting off my HKS BOV and welding on a vband TIAL bov.
#15
Evolved Member
iTrader: (20)
Join Date: May 2007
Location: houston
Posts: 660
Likes: 0
Received 0 Likes
on
0 Posts
Now, that being said... just to make sure the HKS bov wasnt leaking, we TIG welded a new vband flange for a TIAL bov. Tested and works flawlessly... but the surging is still there. In fact i upgraded the bov for no reason...haha. After reading the above comments... im assuming then the FPGreen just has a tendency to surge at low rpms/high load gears. I just didnt expect it from a 20g... if this was a bigger turbo i would have dismissed it in the beginning, LOL... Anyone else have a green that surges?