unfortonatly i dont have pics but dave@FUNCTION did my orginal install and had to do the wastegate at the crossover pipe to correct the issue. now i have also heard this will cause uneven pressure on the left/right bank although i have 30k+ miles on the stock block so who knows

 

Any time you vent one bank and not the other there is a pressure differential. I would NEVER do that. This will cause one bank to run leaner than the other.

With my original build I had a 2" crossover pipe merging in to a 2.5" and it came off of the driver side header. Well, my passenger side would always run richer than the drivers do to the restriction. Same thing happens here, if you vent the crossover, it will run leaner, because more air will get in to that bank.

I have the Haltech dual widebands (one in each bank) so I logged this problem. Once I switched the crossover pipe to 2.5" problem went away.


That's just my experience I guess.

This is the proper way to do it (and what you need)






Looks like it's about $300 here:

http://images.google.ca/imgres?imgur...%3D20%26um%3D1

 

^have the external pipe and still overboosted even with a 44mm wastegate

 

can you elaborate more please..

i thought ur car was running very well !!!!!

 

guys check out this project i found online :






























what do you guys think ????


source: http://fliblog.wordpress.com/2009/06/11/1872/

 

I like it until the right angle it takes merging back into the down pipe.

 

That will work just fine.

 

Thx... Any tips!!!!
Is the place of the wastegate ok? Or shall I make it lil closer to the turbo?

Need ur input experts

 

That is fine, if you make it like that you will not have any problems.

People make a big deal out of the waste gate placement and angles here. If you look at the Powerlab kit (well sought after) it only vents one bank with a 44mm waste gate. The wastegate sits at a 90deg angle on the passenger side bank. The banks are 1.5" at the flange, so a 38mm waste gate is more than enough for any single turbo setup on a Z. I think the Powerlabs piping from the waste gate to the down pipe tie in is about 5' long and 1.5" (I believe) diameter, defeating the purpose for a 44mm waste gate.

I am not putting the Powerlab kit down by any means, it is a great kit with quality components capable of very good numbers (so don't flame). I am just pointing out that the particular setup you are showing will be fine, and comparing it to something people here have seen and are familiar with.

 

So to understand whats going on better, the WG's outlet is backing up causing an increased flow to the turbo, therefore higher boost/spike than wanted?

Wouldn't having the WG open to atmosphere solve this problem?

Im no pro, I am just trying to understand whats happening.

 

no.

 

its actually vise versa.. the wastegate is there to control the flow going to the turbo to reduce the pressure.

External wastegates are commonly used for regulating boost levels more precisely than internal wastegates in high power applications,

 

Nah i know how WG's work (i have an external Tial 38mm), my question was to know the reason why your setup is causing spikes in boost.

So far what I understand from what I have read in this thread is that your piping after the turbo is causing too much back pressure, and since the WG's outlet goes into that post-turbo piping, then its not going to properly vent the pre-turbo exhaust pressure and cause spikes and unwated higher boost. Which is why I mentioned that if you had the WG's outlet dumping to atmosphere it will solve the problem (some people just dont like the sound though)

 

Possible Soulution?

http://www.gtmotorsports.com/product...cat=323&page=1

 

its out of stock. and will never be in stock . discontinued

fabrication is the key.. thats why i am looking for tips on building one.

 

well i had the external wastegate pipe and 38mm tial, over boosted

then switched the 38mm to a 44mm, over boosted

44mm on external wastegate pipe and 38mm on right bank and no overboost

 

if you dont mind me asking what caused the overboost? how much boost was your desired amount?