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External Wastegates
https://silviansw.com/forum/viewtopic.php?f=1&t=20272		 Page 1 of 3
Author:  182Go [ Tue Jan 17, 2006 6:43 pm ]
Post subject:  External Wastegates
Just looking through some of the old post about external wastegates and it seems they only seem to be recomended for big turbos running big boost.

In the comming weeks I am looking to change my factory exhaust and go all new. Some of the components I have already bought / decided on.

I have bought a CES dump pipe and I am looking at buying a 3" / 5" Catco metal Cat.

I am looking at something like the GT28R to replace the T25 on the car.

Still in two mind if I get a steam pipe manifold made or go with one of those pretty chrome manifolds. (want to try keep a stock look so leaning towards custom).

The question... If I go with a custom manifold is it worth going external wastegate. The reason I ask is because I figure if all of the exhaust gas is passed through the exhaust housing it should spool up slightly faster. Also I figure it should give better boost control.

Am I right or have I missed the mark completely?
Author:  ZEi250t [ Tue Jan 17, 2006 6:48 pm ]
Post subject: 
external wastegates are for big turbos (or any turbo i suppose) that dont have internal wastegates

so unless you are getting a turbo that needs an external gate, then i dont think it would be worth doing
Author:  182Go [ Tue Jan 17, 2006 7:00 pm ]
Post subject: 
I guess the question remains... I know it is more expensive but is there a performance gain in bottom end response from the planned GT28R?
Author:  Risking [ Tue Jan 17, 2006 7:19 pm ]
Post subject: 
You are not going to notice any difference.

Its easy to do, fitting an external gate to an internal gated turbo however very rarely is it actually needed.
The internal gate flows just fine and does the job so id leave it alone.

With custom manifolds they are more expensive and generally not as neat as the SS autochrome ones getting around. I know many people making pretty decent power from them. One car in particular had the custom manifold removed and an SS fitted.

If you are after a stock position steempipe contact Too_Much_Boost he has one I think he was willing to part with.
Author:  182Go [ Tue Jan 17, 2006 7:31 pm ]
Post subject: 
Thanks Risking, I was looking at getting one made by sureflow but I will flick TMB a PM.
Author:  Risking [ Tue Jan 17, 2006 8:32 pm ]
Post subject: 
Were you the one that wanted to see their work??

I dropped my manifold off to them the other day for someone to call past and look at.

If you go custom would HIGHLY recommend them. Ensure they use 1 1/4 inch material too.
Author:  182Go [ Wed Jan 18, 2006 8:47 am ]
Post subject: 
No it wasn't me, you have a top mount, I am looking at a low mount. I asked you where you got yours from a while ago. Do you mean 1/4"? 1 1/4 seems a litle thick for pipe :) hmmm maybe not if you mean OD.
Author:  Risking [ Thu Jan 19, 2006 8:24 pm ]
Post subject: 
Im talking about the pipe diameter.
Author:  Turbo_Brian [ Thu Jan 19, 2006 8:35 pm ]
Post subject:  Re: External Wastegates
182Go wrote:
I am looking at something like the GT28R to replace the T25 on the car.


The GT28 series Garrets come with a nice wastegate.

I have a GT28RS on my CA18 at the moment which I bought to replace the T25 stocky job, my turbo spools at about 2,300RPM, and hits full boost at 3,800RPM, holds boost right up to 6,700RPM before dropping off slightly (due to inadequite exhaust system).

There really isn't a reason why you would need to look at fitting an external wastegate, the internal holds nicely.

B.
Author:  Risking [ Thu Jan 19, 2006 8:42 pm ]
Post subject: 
That turbo has an identical wastgate to something like a black top oem turbo. They are nothing to write home about just a conventional gate that does its job.

You are right in that the trubo will be out of puff before the wastegate is out flowed.
Author:  182Go [ Fri Jan 20, 2006 8:37 am ]
Post subject:  Re: External Wastegates
182Go wrote:

The question... If I go with a custom manifold is it worth going external wastegate. The reason I ask is because I figure if all of the exhaust gas is passed through the exhaust housing it should spool up slightly faster. Also I figure it should give better boost control.

Am I right or have I missed the mark completely?


What drugs was I on the day I wrote this???? Internal or external all of the gas is going through the turbo under boost it is only when it has too much that it is going to bypass some of it out the waste gate by which time it has already spooled up :roll:

I spoke with Mathew from Sureflow and he has quoted me the same price on both a top mount (which I previously hadn't considered) and a bottom mount.

He said that because he can make a top mount with more even runners it will spool up faster than a bottom mount. TMB was kind enough to send me some pictures of a low mount manifold which looks similar in design to the chrome SS manifold, neither of which will pass for a stock manifold so I am seriously considering going with a full top mount setup.

Anyone know where I can get water / oil line made up a sensible price?
Author:  whyte [ Fri Jan 20, 2006 11:54 am ]
Post subject: 
you want braided lines? go down to pirtek and tell them what lengths and diameter you want. or you can go to www.horsepowerinabox.com and order some braided fittings there or www.gcg.com.au
Author:  DREAMD [ Fri Jan 20, 2006 11:56 am ]
Post subject: 
just something ive heard correct me if its wrong, but i heard if you have a small turbo with an internal gate and you want to run very high boost, you can weld the internal gate and then fit an external gate

is this correct?
Author:  LISTEN 180SX [ Fri Jan 20, 2006 1:04 pm ]
Post subject: 
DREAMD wrote:
just something ive heard correct me if its wrong, but i heard if you have a small turbo with an internal gate and you want to run very high boost, you can weld the internal gate and then fit an external gate

is this correct?


technically, yes you can.. but why would you? much better off getting a turbo that is designed to work with an external gate..
Author:  182Go [ Fri Jan 20, 2006 1:10 pm ]
Post subject: 
LISTEN 180SX wrote:
DREAMD wrote:
just something ive heard correct me if its wrong, but i heard if you have a small turbo with an internal gate and you want to run very high boost, you can weld the internal gate and then fit an external gate

is this correct?


technically, yes you can.. but why would you? much better off getting a turbo that is designed to work with an external gate..


Have seen that done in photos. Kind of reinventing the wheel. It was what I was thinking of doing originally but the popular consus seems to be that the stock / GT28R wastegate works well enough why add complication.

Having said that by putting on an external wastegate if ever I sell the car it would give the new owner the opportunity to change to a larger turbo setup.
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