SilverRX7

I have just finished taking all of the intake, y-pipe, and dp off... I did this for an egr and dp install.

The turbos are just sitting there... now do I make the extra effort and take them off and port the wastegate so Im set up for a mp? How much work is it to take the turbos off? How many gaskets do I need to replace? Any risks in taking them off(such as wrecking something?) and do I have to fool with the turbines and other internal parts when Im just porting the WG? Or is it as simple as taking the turbos off, finding the WG and porting it(as described in threads I searched).

Please let me know... if it's a big deal, I might not do it, but then I tie myself down and will be power limited from now on until I do that....

vudoodoodoo

Port the wastegate.
If memory serves me right, you would need to replace 2 gaskets: block - manifold, manifolt - turbos.
You won't really mess anything up. The turbos are put together as one assembly. You just take the turbo assembly off and them take off the manifold.
The wastegate is part of the manifold, so you don't need to touch the turbos when you are porting it.
Well at least thats what I remember...

SilverRX7

Does anyone know how many bolts hold the turbo assembly to the block?

vudoodoodoo

Check the service manual.

duboisr

The wg is not in the manifold per se the prespool door and waste gate door are in the turbo hot side . The hot sides come off easily and then you can port the wg . This is not rocket science, unless you do it through the manifold. Do it now while you are in the vicinity ,even if you have stock turbos. This will give you better control and prevent boost creep .

dznutzuk

iTrader: (1)

Yeah it's just the whole boost pressure spiking and overboosting problem, as to taking them off be carefull. If you see any bolts not unscrewing easily be cautious. I recommend that you spray all the bolts and nuts with WD40 or something like that to help them unstick. Because of heat, they expand, rust, etc. Now if one of them snaps off, YOUR IN DEEP ****, my friend. Sorry if I scared you in any way, come on now-it's easy to get those suckers off! Ps. be sure to bring it to a qualified machinist to port them, I've seen people trying to port them at home with DIY tools-guess what, that goes straight to the trash bin if the door doesn't seal right!

SilverRX7

What is the turbo hot side? The exhaust side??

http://jt-imports.com/FDtwinturbos.jpg

Would it be the centre of this pic? I think I have to remove the assembly to do this anyways, right?

Haggard

I chose not to port mine, Although I did port my exhaust ports. You are only gaining a 1/16 of an inch. Controlling boost should not be an issue.

Trout2

iTrader: (5)

Once the turbos are off, you should seperate the primary turbine housing for maching. The wg can be ported by hand but it is safer to use a milling machine that can remove a preset amount of material and leave a lip for the flapper to seal.

The turbo assembly has 7 sections: 2 compressor housings, 2 center sections where the bearings are, 2 turbine housings, and 1 center section where the DP bolts up.

To seperate them you need to removed the steel coolant lines on the sides and oil feed line on top. As mentioned, beware of corroded bolts - spray with PB blaster or something like that and sit overnight. It can also be difficult to pull the primary turbine housing off the primary center section.

Gaskets needed: turbo to DP, (2) turbo to exhuast manifiold, (2) gaskets for oil return lines to motor, (8) washers for the coolant lines banjo nuts, and (4) washers for oil lines banjo nuts.

Good luck,
Jack

SilverRX7

Although Im going by the internet, from what I have seen it is a convincing statement that if you go with the MP, you must go with a ported WG... plus, how will it hurt me? I think to reduce the chances of blowing my motor, its worth it... plus the fact that the WG is a limiting factor in controlling boost makes sense...

Thanks for the help Trout2!

I think Im already to tackle it this weekend... one more question, in the steps I need to take, it sounds like
I need to ensure alignment... is there high risk in doing this for the first time?

"Turbo housing alignment does not use any marks. This is only needed if it is taken apart for WG enlargement. Best to do it on the exhaust manifold. Loosely assemble the housing and loosely bolt it to the exhaust manifold. Hand tighten the housing nuts. This aligns the mating surfaces of the housing to the surface of the exhaust manifold. Remove the housing and finish tightening the assembly nuts. Another way requires using a straight edge across the housing mating surfaces to insure that both sides are in the same plane. This way is less accurate. "

from:
http://www.scuderiaciriani.com/rx7/turbo_rebuild.html

911GT2

I agree silverrx7. I've heard of bad boost creep w/a midpipe if you don't have a ported wastegate. Do it now, and save the time later. Unless you plan on keeping a cat.

suprfast

if i ever have the time to take the turbos out i will definately port the WG. i dont think i will have time till i (if i do decide) go to BNR's 3. i took my cat off a couple months ago and it crept like a ****. i had to put in a restrictor plate that is doing a half *** job. do port the WG. dont take any chances. five more hours of labor that you are not paying for will help you from having to do it again after you blow your motor from creeping.
kris

SilverRX7

Im puzzled. I was geared to port the WG until I called Mazdees(a local shop). They said that all I need is remapped ECU and that I dont need to port.

Porting makes sense to me. BUT - If Pettit makes an ECU that plainly says for DP, MP, & CB... doesn't that imply that the ECU can handle the boost dynamics that are associated with a MP?

Trout2

iTrader: (5)

No, boost creep can not be controlled electronically because it is due to a physical limitation (waste gate too small to bypass exhaust away from the turbine). Over the years I hear some people have bad boost creep without porting while others have none. The worst creep will happen in cold weather if its gonna happen. I think it depends on some factors such as health of the turbos and restriction at the muffler. Creep will be most pronounced in 4th and 5th gear under high load.

Its up to you, its really not that much work when you consider the worst alternative if you don't - bad creep and apex seals let go which can cost engine core pieces, turbos and a lot more labor.

Jack

Jack

poss

iTrader: (5)

you will still have boost creep, even with a new ECU and a boost controller. Even though your computer might be able to handle the boost creep, it is still an uncontrolable situation. it will get worse when it gets cold. and if you are running stock injectors, anything over 14psi is dangerous. creeping past 14 is not hard to do when it's cold.

my suggestion would be to port it. it's not that bad to do by hand. just take your time.

SilverRX7

Ok... I think I will do it... not because I have data showing that its required... but simply because I dont see why Mazda would overdesign a wastegate diameter... simple as that. They would of designed the system(with some safety margin)... but definitely not to account for going from 255hp to over 300hp... so I think there is a substantial risk... and like you said, the consequences are high... therefore Im looking at it as med risk x severe consequences = decision to port wastegate....

And I understand there is no downside to porting the wastegate... except for the labour involved.

Thanks for the help guys...

poss

iTrader: (5)

the only downside would be that if you mess up and make it larger than the wasegate flapper, you will leak exhaust gas making spool up slower.

nrolfes1

ehhh if you go too far its nothing a little jb weld won't fix

poss

iTrader: (5)

haha, what kinda temps is JB weld good up to? I have some pesky cracks I need to fill.

Hyperite

Good god no, don't use JB weld on the turbos! That'll flake off the first time you boost. If you *MUST* use some sort of repair stuff, there's something called Inferno which holds up to like 200 million degrees (quite an exaggeration, more like 5000 F).
~Tom

SilverRX7

Almost time to port... 4 more bolts to go... (I take my time - it still being cold as rotten hell here in Canada)

duboisr

Garfinkle has had all the cracks welded up on the BNR-3 set and made a much larger waste gate door . The hole ( port ) is much larger than the stock door is. Can you say control boys and girls. If you can not get a bigger door made, you should know that the prespool door is 1/10 inch bigger than the stock wg door and it will fit in the wg position if you know how.

SilverRX7

Any pics?

turbox2

Depending on what sort of catback you have, porting the WG may or may not work. I'm going through the same boost creep issues right now. I ported my WG not too long ago (used a Roto Zip and grinding stone), and I noticed almost zero difference. I even ported it just a hair bigger than the flapper, but still had terrible creep. I have the Apex GT Spec (very little restriction), which I imagine is the reason I still have creep. I'm now going through the process of testing different size restrictor plates. Anyway, just thought I'd let you know that you may go through all this and not notice any difference at all, but it's worth a try.

Duboisr, how can I get ahold of one of those larger WG doors that you mentioned?

SilverRX7

Ok... I will watch for that. Unfortunately Im doing all my mods at once... so I wont know if the porting will make a difference or not... but I figure better safe than sorry.