Davidov

iTrader: (2)

Yes, I know this question probably comes up more often that anything on this board.
But I need to to this soon, as my exhaust will be getting done soon.

For my 87 S4 Turbo II, with no mods, except for the forthcoming exhaust job.
I will have a boost, A/F, and temp gauge also.

A few questions first:
1)I need to take the turbo off to port the wastegate, correct? Is it hard to take off?

2)What kind of tool to use? An ordinary dremel grinder bit?

3)Port it enough for the flapper to cover it, or make the port bigger than the flapper. I've heard 2 different opinions for the s4 wastegate.

4)Once its ported, will I see the need for more fuel supply?

Thanks to anyone who can provide a step-by-step process, and/or pictures!

Davidov

iTrader: (2)

Ok, so did I ask this weird or something?

I'm not some stupid ricer asking what a wastegate is, and why it's not painted neon orange. I need to hardcore experienced opinions here.

Anything guys.....

1SxyRXy

if you try searching you can come up with alot of things because alot of people ask these same questions. here is what i found after a breif look https://www.rx7club.com/forum/showth...ting+wastegate

2a+RoN

1) yes, the turbo needs to come off. For a first-timer it will take ~1 hr. After that you can take it on and off in prolly 30min. The worst part about it is just the stupid heat sheilds in the way.

2)A dremel will work but I prefer my die grinder.

3)I have made my just a bit smaller than the flapper, just cuz I didn't want to take it too far and have to put on a bigger flapper or anything. Although, somewhere, I did hear that you can take it up to 15% larger than the flapper without ill effect.

4)Your boost is staying where you want it to now, so you will not need to get more fuel unless you plan on raising your boost level via a boost controller.

-Aaron

Davidov

iTrader: (2)

Great, that's what I was looking for Aaron.

Thanks for the link 1sxyrxy

2a+RoN

No problem.

banzaitoyota

Search by my name I did a write-up a while back

Aaron Cake

iTrader: (1)

There's also a write up (with pictures) on Ted's site at http://www.fc3s-pro.com .

banzaitoyota

Ted's site is still down Aaron

NZConvertible

Some people who've ported only to the edges of the stock flap have still experienced boost creep (depends on other mods), but if you port past the edges of the flap it leaks (obviously) and reduces the turbo's response, i.e. more lag.

You should look at replacing the flap with a bigger one so you can go much bigger with the port. This is a pretty simple job for a turbo shop if you haven't got the tools to DIY.

astrochild7

iTrader: (3)

find a ss washer and weld it to the existing flapper.. then deck the top of the flapper hole down the same thickness of the washer then you are free to mill the wastegate freaken huge.. you also can mill the walls around the wastegate to increase flow... you can alsp mill the backplate edge for more flow i did the same and no boost creep this turbo is upgraded on the cold side w/a v-trim to4 compressor milled stock cold side> >>> turbo is for sale<<<< PM me!!!

silverrotor

iTrader: (1)

I couldn't find It via search function.

banzaitoyota

Here you go:

https://www.rx7club.com/forum/showth...hreadid=137586

Cheers!

true, if port past he edge of the flag u will lose response.

But if u have an aftermarket boost controller (profecB, apexi AVCR, ball and spring) this should still be ok. since hte stepper motor/solenoid/ball and spring will prevent the wastegate from see any pressure until the boost controller starts to bleed boost off when it reaches desired boost level.

silverrotor

iTrader: (1)

Thanks for the response. Can these principales be used for a s5 Turbo?

What was contained In the Turbo Kit you used?

banzaitoyota

I have never done a S5, so I would only be regurtiatating someone else's experience. The Kit contained the all the software needed to refurb the turbo

NZConvertible

It doesn't matter if you have a boost controller or not. If you port past the edge of the flap the wastegate will leak all the time no matter whether the flap is open or closed, so the turbine will never be seeing the full exhaust flow.

Lazy-Rx7

1) yes the turbo will have to be taken off. the only difficulty getting it off is getting to all the heat shield nuts and moving/removing them to get to the manifold nuts. that and wrestling it out of the car, it's not hard though, just time consuming.

2) a dremel would be okay, but i used an ingersol-rand die grinder with titanium hydride coated porting bits specially made for porting. also threw a 5.5hp 26 gallon air compressor in the bunch.

3) if you would like to up the boost more than stock never go past what size flapper you have. in this case, i got an exhaust valve from a integra ls head, cut the old door out, and welded the new door to the arm. i then ported according to the size of the new door.

Check in the FAQ section, there is some information there. Also if you haven't already, pick up an FSM or a Haynes manual, this will help alot with this, and many other projects/questions you might have. if you have any more questions feel free to e-mail me.

-Steven M.
Sleeper-Z@houston.rr.com

P.S.

while you're doing this, you might as well balance the runners on the manifold. stock, there is one big opening on the right and to the left there is one slightly smaller in size. to do this you will need to gasket match it and then port accordingly.