shoffs30

I have a 0 plate full forward, 3k gsk, gutted afc (for now) currently installed and 370 injectors will go in next weekend. My problem is that even without the injectors, by boost will easily spike to 45 psi. I am sure it would go higher than that, but I don't want to do any damage so I keep my foot out of it. What is the best way to check to see if my wastegate is working. I want to limit my boost to about 35psi with a JoeP mbc I bought. Thanks

plow

unhook your wastegate line at th AFC and blow compressed air into it, you should be able to hear your wastegate working. With that kind of psi you should do the turbo mod so the wastegate can gate all 6 cylinders.

wannadiesel

Two ways to fix it. The quick way:



The right way:

shoffs30

So the lower picture is not the same view as the top picture I take it. Since I have never had the housing off, could you either show a before picture or explain what you did in the "right way" picture to allow all six cylinders to go to the wastegate. It will probably be more obvious when I take it all apart this weekend, but I try to fully understand a job before I start it.

wannadiesel

The first pic is my work. If you look in through the wastegate port, you can see another hole. That wall is solid from the factory. Drilling a hole through it allows pressure from the front half of the housing to bleed into the rear half, where the wastegate will relieve the pressure. It did the job and allowed the wastegate to control the boost again. Before I did that, I could make 35 psi with the wastegate wired open. Basically the front 3 cylinders were running the turbo.

Northslope did the second one. That's an "exhaust manifold's eye" view. What he did was grind the whole divider out, as well as gasket-match the flange. Much better from a flow standpoint, and much more time consuming.

northslope

After I did got...DIESEL?'s housing I found that if a guy wanted he could safely open it up to the leading edge of the w/gate hole. In this picture that would mean about another inch of material removal. I didn't because I didn't have a long burr at the time. I think it a wise choice if you do any grinding to make sure NOT to knife edge the divider but yet bull nose it and blend all the areas well. High heat may and probably will cause cracks if not.

mytrucksaslug

that looks very interesting. did it make a noticable difference in performance? is it something a novice can do?

shoffs30

northslope,
did you put a larger flapper and enlarge the wastegate hole on your setup. there is another post with pictures right now showing it. i would rather not go to that effort if just grinding the divider will give me end result i need.

northslope

I opend the hole just a hair then decided to see just what the changes were with the partition removal.



That is the housing that I did for my broher got...DIESEL? and yes he hogged out the w/gate hole and made a new flapper for it. As for the mod on my hsg I did notice a big difference.

The advantages I noticed are (according to my vehicle yours might vary):

1) quicker spool

2) smoke reduction under load

With just this turbine housing mod

northslope

If you've got a pneumatic 1/4" die grinder and a rotary rasp like this:http://www.acehardware.com/product/i...archId=1259453 it'll work great. Just make sure to turn down the RPM on the die grinder till the rasp quits throwing sparks

mytrucksaslug

heres a real dumb question. I could get one of those grinders and that bit, i could even look at the part from my truck and match it to that picture. is that part in the picture the turbo, but all taken apart? is there any special trick to doing that? I would attempt it if its just a simple thing to take it apart and put it back together. Would i be able to spot that part where you drill a hole? that would seem like the first thing to do, then try grinding it. I guess it would be best to just do it all at once of course. its a great mod because it doesnt look it would cost much which makes the wife happy.

northslope

This is how I did it
To Take the turbo apart:

1) remove turbo from truck

2) take 4 bolts that clamp the turbine housing to the center section out

3) I had to use an oxy-acetylene torch, I used a cutting tip, to heat up just around the area in which it makes contact to the center section.

4) quickly use a big dead blow hammer to knock the housing off while it's still hot.

MAKE SURE YOU DO THE GRINDING WITH THE TURBINE HOUSING OFF THE TURBO!!! Cause you'll end up with about a cup full of iron filings, you DO NOT want to run these through the turbo!

To make things easier what I did was get a good used 12cm housing modify it at my leisure then I've got one ready to go. If you don't it'll potentially take more than a day to do.

Go here and download the correct manual for your turbo here:http://www.holset.co.uk/files/
Then hover your mouse pointer over the tab on the top right that says "parts and service" then go to service literature select "service re[air manuals" and there's a quick reference sheet you can download too that says "reference sheets". These will show you how the thing comes apart and it'll give you torque specs (not that you'll need them in this modification)

let me know how it works out for you!

mytrucksaslug

that is starting to sound a little intimidating. I'll have to see if i can get my buddy to tourch it for me. just hate having to use a torch on an expensive part, but its probably not a big deal. thanks for the link to the service guide.

shoffs30

So let me check one more thing. I understand that you are grinding the divider back like your picture shows on the port connecting to the exhaust manifold. After that, are you just drilling a hole through the divider the same size as the wastegate opening at the very back part of the housing to allow both chambers to mix. I guess I was wondering why you don't just grind the divider completely away. Is it necessary to leave part of it there for structural support or flow or something else?

northslope

No. There is no need to drill the hole through the divider if you grind the partition back. You accomplish the same result whether you grind it back or if you drill through it. The two pictures listed in this post are different housings with different approaches to achieve roughly the same result.