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Wastegate hose assembly

2

2ltrex

Member
I'm am a little confused on the whole wastegate assembly sizing.

Can i just go to autozone and replace the hoses with a similar size (5/32 or 7/32) or do i have to find the whole assembly?

There is also this y-orfice that has a restrictor on it and apparently it also has to be the right size (different than the GN). I have seen .040 and .028 mentioned. Which is correct and how do i know if i have the right one?

I found a diagram for the direction of how its suppose to hook up so i'm ok with that.

I'm just looking to replace some hoses due to recent erratic high boost levels.
 
I had to put a complete new wastegate hose assy. on my TTA when I first got it, I did not even have the original hose with the "Y" and the orfice.

So I was lucky enough to get help you one of the worlds leading authority on the TTA, John Pearcy from Johns Performance. He helped me out a lot, I would e-mail him pics. and he would tell me what to do. He is no longer in business, that is too bad for all of us.

He told me to get a complete wastegate hose assy. and I got that from Kirbans, it was for a GN so it had the .050 orfice which was wrong for the TTA.

So John sold me a .040 orfice to install in the GN "Y" and it works great. I wish I would have got more than 1 of the orfices from him, for spares.

Here is a pic. of the instructions for installing the .040 orifice I got from John.

If you have the correct orfice in the "Y" you can change the hoses, I would probably buy a GN assy. and just change the "Y".
 
TTA984 said:
I had to put a complete new wastegate hose assy. on my TTA when I first got it, I did not even have the original hose with the "Y" and the orfice.

So I was lucky enough to get help you one of the worlds leading authority on the TTA, John Pearcy from Johns Performance. He helped me out a lot, I would e-mail him pics. and he would tell me what to do. He is no longer in business, that is too bad for all of us.

He told me to get a complete wastegate hose assy. and I got that from Kirbans, it was for a GN so it had the .050 orfice which was wrong for the TTA.

So John sold me a .040 orfice to install in the GN "Y" and it works great. I wish I would have got more than 1 of the orfices from him, for spares.

Here is a pic. of the instructions for installing the .040 orifice I got from John.

If you have the correct orfice in the "Y" you can change the hoses, I would probably buy a GN assy. and just change the "Y".
Click to expand...

Yeah, John was great. He helped me get my car running well when i first bought it. Was always helpful with answering questions. Like you, I would have went to him but have been without his input for a few years since he left the business.

I've seen the wastegate hose assembly
http://www.nos4gn.com/servlet/the-4/Buick-Grand-National-parts/Detail

didnt see one on kirban. Is there something unique about the tubing that makes you buy the whole assembly?
 
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2ltrex said:
Yeah, John was great. He helped me get my car running well when i first bought it. Was always helpful with answering questions. Like you, I would have went to him but have been without his input for a few years since he left the business.

I've seen the wastegate hose assembly
http://www.nos4gn.com/servlet/the-4/Buick-Grand-National-parts/Detail

didnt see one on kirban. Is there something unique about the tubing that makes you buy the whole assembly?
Click to expand...

That was like 2 yrs ago I got one from Kirbans. Here I found another one at g-body parts.

http://www.gbodyparts.com/product_i...d=904&osCsid=2bc0b532b0e51543a6167c549ace2a60
 
O.k,I have to ask,what in the world would make the "Y"diff from the GN's to the TTA's ???? I know you say orifice size,but.....????? Same engine/turbo setup,ntm same wastegate solenoid????ECM tells the solenoid when to bleed off pressure,coming from the programming of the prom(chip) ??
Reason is,when I got my car,it had an aftermarket boost controller on it with NO "Y" connector,I removed it and switched the stock line and "Y" from my GN.It seems to be working fine.Just sayin.....
 
ev2 aar said:
O.k,I have to ask,what in the world would make the "Y"diff from the GN's to the TTA's ???? I know you say orifice size,but.....????? Same engine/turbo setup,ntm same wastegate solenoid????ECM tells the solenoid when to bleed off pressure,coming from the programming of the prom(chip) ??
Reason is,when I got my car,it had an aftermarket boost controller on it with NO "Y" connector,I removed it and switched the stock line and "Y" from my GN.It seems to be working fine.Just sayin.....
Click to expand...

This is a good question for Scott Kelley. The TTA had the .040 orfice stock for good reason I am sure.

May be Jan or some of the others will chime in.:yes:
 
TTA984 said:
This is a good question for Scott Kelley. The TTA had the .040 orfice stock for good reason I am sure.

May be Jan or some of the others will chime in.:yes:
Click to expand...
From what I've just read,they were saying the "newer" wastegate hose "Y's" had a .050 orifice.Does that mean an original one off a GN "was" .040?
I sure would like to know,as I said same turbo,ECM,wastegate sol,what could poss change how boost is built other than maybe the torque convertor was a diff stall speed.But that would only affect how long or fast it will build the boost.
I mean even back in the days of me and friends messing around with our GN's,from stock turbos,TA49's TE60,62 ported heads,front mount intercoolers,etc,still used the fact wastgate assembly and fact "Y" connectors.The TTA was not that radical to that level.FWD head change,and diff fins per inch on the intercooler is nothing.
 
ev2 aar said:
From what I've just read,they were saying the "newer" wastegate hose "Y's" had a .050 orifice.Does that mean an original one off a GN "was" .040?
I sure would like to know,as I said same turbo,ECM,wastegate sol,what could poss change how boost is built other than maybe the torque convertor was a diff stall speed.But that would only affect how long or fast it will build the boost.
I mean even back in the days of me and friends messing around with our GN's,from stock turbos,TA49's TE60,62 ported heads,front mount intercoolers,etc,still used the fact wastgate assembly and fact "Y" connectors.The TTA was not that radical to that level.FWD head change,and diff fins per inch on the intercooler is nothing.
Click to expand...


I have a NOS wastegate hose still in the box, which is the older one you are talking about. I would hate to remove the orfice and check it out.

The wastegate hose I used on my car was the newer type, but I saved the .050 orfice after replacing it.
 
the TTA had a diffrent turbo an prolly wastegate because of lower compression it had more boost than the GN's had ... diffrent pistons an heads an crank an so on gn = lc2 TTA is a SG1 block
 
Also,just like the GNX's had their boost raised from 12 to 17psi,by way of the prom.Probably why they figured they had to change the intercooler from 10 fins per inch to 12,to cool more of the charge.
Which again,I have a TA49 on my GN and have run 20-22lbs of boost with stock intercooler,running off the orig wastegate sol setup.Gone 12.20's @ 112mph thru it.
Never did measure the orifice in mine though.
 
Anyway,is'nt that the concept behind the RJC boost control.It is spring loaded to hold back pressure to make the spool up quicker,then let it get to the solenoid to bleed off the presure ?????
 
ev2 aar said:
Thought they were both 8.1:1 ?
Click to expand...

87 GN is 8.5:1
GN stock piston 8:5:1

6ed23a65.jpg


TTA stock piston beside 20. over je tta piston 8:1


Picture261.jpg



see the deeper dish on the tta ?
 
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ev2 aar said:
O.k,I have to ask,what in the world would make the "Y"diff from the GN's to the TTA's ???? I know you say orifice size,but.....????? Same engine/turbo setup,ntm same wastegate solenoid????ECM tells the solenoid when to bleed off pressure,coming from the programming of the prom(chip) ??
Reason is,when I got my car,it had an aftermarket boost controller on it with NO "Y" connector,I removed it and switched the stock line and "Y" from my GN.It seems to be working fine.Just sayin.....
Click to expand...

TTA984 said:
That was like 2 yrs ago I got one from Kirbans. Here I found another one at g-body parts.

http://www.gbodyparts.com/product_i...d=904&osCsid=2bc0b532b0e51543a6167c549ace2a60
Click to expand...

Ordered last night from gbody and got a notice this morning that its been discontined and not available. Damn! Looks like nos4gn maybe only one. Not sure if they have updated their website either though
 
The wastegate hose was discontinued over a year ago. Also the belt tensioner assy for the TTA and GN has been discontinued also. Both are hard to get items now. Some bringing a premium price.

Looking at my spare wastegate hose the size of the tubing is 7/32 except for the small hose on the right of the picture and it is 5/32. As long as the "Y" is available it could be put together with vacuum lines.
 
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