Overboosting GT35 + TIAL 44MM EWG

[Cressid@]

Hey guys,

Again ive searched and searched and stumped with what to do nows

Ive converted my auto 1jz to a GT35, 6boost manifold, TIAL 44mm mvr ext gate, 3 inch exhaust but im still using my jzx81 fmic. Also ive plumbed the ext gate back into the exhaust and running a emanage ultimate which still has the old tune from the twin turbo setup.

Now since converting, its overboosting like crazy..love the feeling but man im worried im going to blow something. For eg i saw it spike once up to 25psi.
Now I ran a straight pressure hose from the wastegate to the outlet of the turbo so i was running just the spring pressure. (1 bar). Now if i put my foot down from start and stop it takes off. It lags abit and starts to build boost as normally..once it hits around one bar mark i can hear the wastegate open then it shifts up gear. Seems to be operating fine...Now if i come around a corner or at a certain speed and and plant it, it downshifts and takes off...now if i keep my foot down..it over boosts like crazy.

I installed a gizzmo ms-2 boost controller to see if that makes a difference but nope..still the same

It sounds wierd but thats what im noticing.

This is what im thinking

- Wastegate is faulty
- The nipple for the pressure hose to the wasegate isnt 100% sealed ( i just drilled a hole into the cooler pipe closest to the turbo as possible and screwed a hose fitting into it)
- Intercooler is too restrictive
- The tune

any ideas?

[NME308]

Hi there,
Thinking in print here... The 6boost manifold has the wastegate mount built in does it? I vouch Kyle would get it right if it is built in to his manifold - however a poorly mounted wastegate will struggle to ditch air in sufficient quantities.
What A/R is the turbine housing? Somewhat pertaining to above, a small turbine housing will need more gate (or at least more efficient gate) to get rid of back pressure. Dont get me wrong I am a huge fan of small exhaust housings!
Since you have been using an EBC do you still have the hose to the top of the wastegate diaphram when attempting to bypass said EBC for testing?
Since you ran the EBC previously on the stock twins I imagine it would need another set of instructions before it would control an external gate. Internal and external gate usually use very different control circuits.
A worn wastegate will most definatly struggle to control boost of course! I had a pair of ancient garrett 42mm units with badly worn brass bushings and they would hold air pressure under the diaphram and overboosted like crazy. Broken or perished diaphram will give the same result.

Just a few quick thoughts...

Cheers,
Jason

[thechuckster]

remove WG from car, pump up boost reference port with a bike pump, hold at various pressures (will require gauge fitted to the line), listen for leaks and watch for valve operation.

I recall Wilbo buying an external gate ex-eBay and it required surgery to fix.

[Cressid@]

Hey guys, yeah the 6boost manifold has the gate mount built in.the exhaust shop just welded the angle pipe in to get the right angle. The rear housing is . 82 and the wastegate is new. Regarding the ebc . I've read and tried all the options in both the tial wastegate instructions and gizzmo instructions. With ebc and without. Either way it seems to be the same thing

Holds boost in one gear then when shifts to the next overboost. I'm thinking it could be the existing tune but I'm not exactly sure if it would effect it.

I'll take the gate out and test it again but last nite I will correct what I said earlier about it opening at 1bar. Went for a run and without fail it opens at roughly 11 psi without fail then shifts to the next gear then overboosts. Currently the emanage has two tunes set. One for race and one for everyday driving.

[stradlater]

I have had to pull apart my tial a few times before to lubricate it when I had issues like this.

Under normal test conditions the thing worked fine, but when it was running fast and hot in the car, then it wasn't so good.

This could be it..?

[Cressid@]

hey Stradlater..

that sorta sounds like it..ill pull it apart this weekend and have a look

is it supposed to need lubrication regularly? what lube would you use though?

[Shifty]

Hi mate

Assuming all the common-sense stuff is right (ie. hoses plumbed up right - check EVERYTHING from scratch, don't just think "yeah that's right, I remember doing it"), then the most important thing is to review exhaust and intake restrictions.

First thing is to fit a basic screamer pipe - even if just temporarily to check if that's the problem. Exhaust shop should be able to make for $100 if it's not too complex. It's all good and well to have an external gate but if it can't flow the required amount of gas then it can't control boost.

Also that intercooler MUST go. It's a joke to run a $5k hotside and a $50 intercooler - it might be causing your problems too, but even if not it will AT BEST cost you power and at worst cost you an engine & turbo.

[e30-323ti]

It's all good and well to have an external gate but if it can't flow the required amount of gas then it can't control boost.

Ditto.

Also, have you checked at all speed/gear changes??

The lower gears (1st/2nd) may not load the motor up long enough to get 'too much' exhaust gas flowing, thus on the 2nd/3rd or say 3rd/4th gear change (or even 4th/3rd downshift), the extra load of the taller gears gives more time/exhaust gas to overwhelm the WG flow capacity (if that is the problem).

[Cressid@]

shifty..ill give the screamer pipe a shot this weekend

e30-323ti... you are quite right about the lower gears not loading up the motor because the next gear up loads and revs way up more but its so weird that the gate does open just at lower boost levels but one it loads up in the higher gears theres no holding it then

Now i just spoke to kyle (6boost) and my exhaust guy and they are guessing the wastegate is too small. They are recommending a 50mm turbosmart item as they have had this issue in the past with other customer cars.

im quite confused because i read other people having 44m wastegates on my setup with no problems

ohh the fun continues lol

[abently]

shifty..ill give the screamer pipe a shot this weekend

e30-323ti... you are quite right about the lower gears not loading up the motor because the next gear up loads and revs way up more but its so weird that the gate does open just at lower boost levels but one it loads up in the higher gears theres no holding it then

Now i just spoke to kyle (6boost) and my exhaust guy and they are guessing the wastegate is too small. They are recommending a 50mm turbosmart item as they have had this issue in the past with other customer cars.

im quite confused because i read other people having 44m wastegates on my setup with no problems

ohh the fun continues lol

You have to be kidding right....

Anyway, how is that Wastegate plumbled in exactly?

Can you post pics or at least do a diagram of the angles and so fourth?

You don't need a screamer pipe, you just need a well designed and fitted wastegate, exhaust plumbing....

The outlet from the WG should be angled into the dump pipe at 45 degrees or less, and the outlet off the 6BOOST manifold into the WG should be the same size as the WG inlet.

A T04Z can be run at low boost with a 44mm WG so it is definately not a size issue, even though going to a bigger size will bandaid the issue...

[Cressid@]

abently..ill take photos of it and post it up tonight for all to see

[stradlater]

Just to give you an idea Cressid@ - I run a GT4094, on a 1uz, with a Tial 46mm wastegate.

So you should be able to use a 44...


Also, the lubricant you need to use is a nickle based thing, it's copper in colour. Can't remember what it's called. GCG should know.

[Cressid@]

alrite guys, this is the best picture i could get using my iphone.
Let me know what you guys think
Currently the plumb back goes all the way down and connects just before it angles up
If that makes sense

[abently]

alrite guys, this is the best picture i could get using my iphone.
Let me know what you guys think
Currently the plumb back goes all the way down and connects just before it angles up
If that makes sense

Hi mate,

I think you will be better off drawing a pic....

Is it v-band on both sides of the WG? Do you know what the ID of the piping is that goes into and out of the WG?

You might just need to pull the manifold off and radius the edge, where the WG piping connects into the manifold? Actually PM 6BOOST to confirm if this is necessary, as it may already have a decent radius on it?

What angle does the WG exit piping go back into the dump pipe?

Also, is the WG port on the manifold at the collector right next to the flange, and/or shielded internally a bit to exhaust from only 3 cylinders, not all 6?

If you were in Adelaide, it would have been much easier to just pop over and have a look...

[Cressid@]

Update!!

Today I removed the plumb back pipe and what do you know...
The wastegate Is stuck open. I can hear the gasses coming through the screamer.
So what's odd to me is how does it overboost??
I'm going to remove the gate and ask for a refund or exchange it.