First time i went to port my wastegate was right before installed my motor and i didn't really take off much. I was scared i would screw something up. So today i took it off again becouse i was getting terrible boost creep. I ported the sucker for about an hour. I wore down 4 rotary rasps that i bought at home depot. The smaller of the two holes can just about fit my thumb and the opening on the bigger one is just to the edges of the flapper. I have my wastegate plumbed directly to the nipple on the turbo. with my 3" intake and exhaust it creeps to about 8psi in first and in second it goes to about 10psi. Now to my understanding the stock kouki wastegate has a 5psi springs and that is what i should be boosting now that i ported the wastegate. Do i need to go bigger? Is my wastegate plumbed wrong? What is going on?

 

Even with porting to the edge (or even a bit beyond) the WG flapper, the boost will still creep to 10psi or so if you're running full exhaust/intake. Then again, I only have experience with s4 Turbo II's, which have a single WG exit.

If you really want to keep the boost down while running a full exhaust/intake you've got to have someone weld a larger diameter flapper on there. You could probably make a decent flapper by getting creative with a larger washer. 30mm or so?

 

i dint thing it was necessary to wled a bigger flapper on the superior kouki turbo wastegate. Could be wrong though. Do i have my wastegate plumbed right?

 

9-11 psi is totally normal for bolt ons and ported wg... All mods that improve airflow, also raise the boost... Nothing you can do about it, except go back to stock intake and exhaust... The porting of the wastegate is to keep the boost from continuing to go up, as in 15psi and above...

 

i was just going off this statement from the kouki wastegate porting guide on fc3spro.com.

"The FC that this wastegate porting was done to "unfortunately" had the wastegate rod fall off the wastegate lever. The clip that normally holds the rod in place was not installed. The FC was still going through break-in procedures (about 500 miles on rebuilt engine - rev limit at 6kRPM), so the boost loss was not a big deal. With a Défi boost gauge monitoring boost levels, the FC with the unsecured wastegate managed to produce only ONE psi of boost! The exhaust is a 3" straight through exhaust, with a 3" downpipe flowing through a single muffler. This is a testament on how effective the wastegate porting can be on this Kouki turbo wastegate... "

 

Yea 1psi with the wastegate wide open... If you had the mods you have now with an unported wastegate, you'd be creeping to 15-20psi...

 

oh ok i understand now. So there is really no need for a boost controller on a stock turbo becouse the wastegate really puts you right were you want. Unless with a mbc you got straight to 10psi and the the wastegate opens instead of the wastegate opening at 5 psi and then creeping to 10psi. sound about right?

 

A boost controller will only raise the boost, not lower it, if that's what you're asking... 10psi is the lowest you'll be getting, and anything else from here on out will only make it higher... If you're comfortable with 10psi then you zero out the boost controller if you have one, or leave the vac line connected to the wg actuator... The wastegate just bypasses any pressure that's higher than the spring will allow... Exhaust and intake mean more pressure, and that pressure overwhelmes the wg unless you port it to allow more excess boost to escape...

 

my s4,(K&N intake, custom TID, COLDAIRI, down pipe+str8 pipe)hits 8 psi immediatly, then by 5.5k ends up at 12psi in most gears, in 4th and 5th, it would easily go to 15-20 psi, i am porting my WG tomorro becuase of this, but i will be going to 32mm :P. so then i will be use a boost contoller to go streight to 12 psi every time i get on it. which will deliver a smoother power band then hitting 8 psi then creep to 11psi and let the boost spike up and down from there on out, so port the waste gate a bit more, and put on a simple manuel boost controller and enjoy :P

 

Think of the wastegate like a dam... The higher the dam, the more water that will fit behind it... Once the water reaches the top of the dam, all the excess spills over the other side... Well you lower the dam and it spills more over... That's a really shitty analogy, but it's the same concept...

 

You're letting it creep to 15psi? That's not good at all...

 

you should be hitting fuel cut at ~8 psi

 

He probably has a FCD installed...

 

I know, shh...

 

well i have the old school racing beat boost guage/ controller right now i have it just reading boost from after the throttle plates and have it closed off so no boost leaks out the open end. Is that where i should get my boost signal from. Then should i run the other end to open the wastegate. The only problem is currently the wastegate is opening from boost before the throttle plates and if i plumb in the racing beat controller i'll be getting boost from after the plates to open the wastegate. is that ok to do?

 

sorry add FCD too my mods list also, but the DP and FCD were in the car along with the 720CC's also, yes i have been getting on it and it went to 1 BAR on my gay *** boost gauge( previously installed also)...
but thats why i am porting it tomorro... the rumor is the origonal engine blew some apex seals out at 19psi, which the other guy had not a clue to what he was doing...

 

19 psi on the stock turbo??

 

ok, but lets not get side tracked here.

 

I can see why... Dude you CANNOT spike the boost like that... You WILL blow your engine... One time is one time too many... There isn't a whole lot of room for error with rotaries...

 

anyone any comments on my last post?

 

i know it will never hit that, i have alot more control over it, when the engine blew the guy gave up on the car and left it in a walmart parking lot, it then got towed, and the guy a bough it from got it outta impound for 300..

i plan on 12psi with the top mount and then 14.5 with the front mount, in good time, as for you driftin8ez, port it, install boost controller, enjoy it, period.

 

well i already have the old school racing beat boost guage/ controller right now i have it just reading boost from after the throttle plates and have it closed off so no boost leaks out the open end. Is that where i should get my boost signal from. Then should i run the other end to open the wastegate. The only problem is currently the wastegate is opening from boost before the throttle plates and if i plumb in the racing beat controller i'll be getting boost from after the plates to open the wastegate. is that ok to do?

 

move the vac line for the WG to a nipple after the butterflies

 

ok thanx. will do. So basically with my 3" intake and exhaust it is very hard to go back to stock boost levels correct?

 

yes, unless you add a restrictor plug for the intake or go back to the stock exhaust.