Jump to content

Solving Boost Spiking On The Gt3540


DennisRB30

Recommended Posts

  • Member
  • Member For: 21y 6m 9d

Seems as though its a bit of a secret to how big the gate needs to be ported.

I ported mine for an 82% increase, but am yet to fit the flapper. Can anyone tell me if the 82% increase is big enough? I can go to 100% if I need to.

So if the gurus don't want to give away their secreted can they please tell my if 82% increase is big enough?

Link to comment
Share on other sites

  • Replies 32
  • Created
  • Last Reply

Top Posters In This Topic

  • Member
  • Member For: 19y 2m 14d
Seems as though its a bit of a secret to how big the gate needs to be ported.

I ported mine for an 82% increase, but am yet to fit the flapper.    Can anyone tell me if the 82% increase is big enough?  I can go to 100% if I need to.   

So if the gurus don't want to give away their secreted can they please tell my if 82% increase is big enough?

I am no expert,having a look at mine recently as long as your new flapper still covers the hole should be ok.

Link to comment
Share on other sites

  • Member
  • Member For: 21y 6m 9d

You get around don't you Cubes? :)

Anyhow the stock flapper falls straight through the new port. I got a bigger one made up. You can't really go too much bigger without upgrading it. I am get to connect it all up. The arm also needed mods as the new port is off centre to the old port.

Link to comment
Share on other sites

  • Member
  • Member For: 21y 6m 9d

Finally some info on the proper port job! Thanks mate.

Looks quite similar to what I done. They done a 36mm flap and I done a 38mm flap. My new port is 34mm not sure on theirs. I think mine would be a couple of mm bigger. It also appears they had to offset the hole. They made is small enough and offset the hole in such a way that they didn't need to machine a new seat like I did. That was the sort of info I wanted to save a lot of f*cking around making a new seat etc.

Oh well, mine sure work even better since its a bit bigger.

Link to comment
Share on other sites

  • Member
  • Member For: 18y 1m 27d
I got my waste gate ported apporx 6mm larger than the standard circumference and fitted an 11.5psi actuator. The difference it made is fantastic. Obviously the lowest boost I can run now is 1.5 psi but I can actually use my eboost to create a boost profile now. Before in high gears and high rpm the boost was impossible to control properly. It cost me $50 for the machine work and $117 for the actuator. Some other members also had there flapper valve change and had similar success with that and porting the waste gate as well.

Thanks mate! Please tell me as much info as you can guys.

My boost control is shocking ATM and I get creep up past 1 bar in the top end, and I haven't even fixed my 3" exhaust which has been damaged and is probably restricted to 2.5 inches. How big is your exhaust? Its very difficult to set a flat boost curve how it is.

I can't see how you got it ported out 6mm without a new flap valve though. It appears as though there is only about 2 or 3mm overlap with the stock flap.

I think he said that the circumference was increased by 6mm, if you say there was 2-3mm overlap I imagine that would be plenty because even banking on the smaller option the diameter of the bore is still approx 4mm greater than the flapper, and increase of that diameter could increase the circumference by approx 6mm (circumference of a circle= pie(3.14)xdiameter. keep the updates comming both of you, Im gonna have to do the same mod soon.

Link to comment
Share on other sites

  • Member
  • Member For: 21y 6m 9d

Circumference! I missed that. What an odd way to describe the size increase. I guess if the guy doing the work says the new hole is only 1.9mm wider it sounds pretty pathetic :blink: that's still about a 15% increase in size though. Mine is like 65% bigger :spoton: Its pretty much finished.

http://www.math.com/students/calculators/s...rcle-solver.htm

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
  • Recently Browsing   0 members

    • No registered users viewing this page.



×
  • Create New...
'