How do I ad external wastegate to GReddy Manifold?

I've done a search and found a few threads where people have added tial wastegates to the GReddy kit. How can it be done and is it neccessary (with MadDog/MazdaManiac's setup)? I know the manifold is cast iron and the room is clausterphobic tight.

 

Good question, I´d really like to know how that setup looks like... and time for a newbie-question; What´s the benefit of using an external wastegate instead of an internal one?

 

External waste gate are more reliable, more acurate and it is a lets of a restriction to the exhaust path out of the turbo. Now how you add a external one to a Greedy kit? I have no clue.

 

weld the greddy gate shut then mount the external wastegate before the exahust housing on the pressure side then run the blown off gas from the waste gate around the turbo and into the downpipe. Seems logical.

 

Refraized your post for better understanding. Even though it is logical the question is more of a fitment issue than as how to intall it. Since I have never seen a Greedy exhaust manifold I don't know where it would be ideal to mount the W/G. Understand?

 

Hybrid added an external WG to his Greddy kit. Look in the post titled Greddy CAI, he has pics posted.

 

....thinking... What´s behind the wall on the passenger side of the turbo. Maybe just take a hammer and hit on it to get some extra room down where the turbo and downpipe are located?

 

one more thing... what´s the advantages and disadvantages of having the wastegate dumping the air out to the atmosphere or back to the downpipe? Other than noice...

 

Dumping the WG pipe will be loud. Feeding it back into the exhaust stream can cause turbulance which can increase the pressure directly after the turbine outlet, effectively decreasing the pressure delta across the turbine. This results in more turbo lag, and less energy overall to feed the turbo. Essentially, the turbulance will act like an exhaust restriction. This can be minimized by plumbing the dump tube farther downstream from the turbo, and plumbing the tube using a shallow angle.

 

So an external wg is "better" than internal ones... no matter what turbo or psi you are running? If so, I have no doubt in changing my setup.
What WGs are recomended for the GReddy turbo?

 

My answer compared the two scenarios for an external WG, since that is what you asked. I didn't say anything about an internal WG.

The internal WG configuration usually feeds diverted exhaust gas back into the main stream pretty well as there is a 0degree angle between the 2 gas streams. An external WG is better if you are having a problem controlling boost. An external WG can possibly be better to alleviate premature WG cracking, but a good boost controller and a hard enough spring can usually also accomplish that.

With the Greddy kit, I think the boost falling off is partially caused by exhaust gas pressure at high rpms forcing the WG open. The external WG will fix this, and I believe that is why Hybrid was able to make 310whp.

 

Internal ones tend to work OK on smaller flowing turbos. The external ones are needed as the flow increases to ensure they flow enough. The Greddy ones problems seems to have more to do proper sealing and having a stiff enough spring to stay closed....not so much the flow. They can be modified relatively easily if you have fab skills for better flow....

 

Partly my thoughts as well when reading this thread and having Hybrids posts in my backhead. This is definately the setup I´ll go for!!! (along with a bigger turbo)

 

I definitely remember Manuel was probably the first one on this board that went this route. He had to to get to the 12-14 psi he was running.

 

^ Yep. I have his old setup minus the external WG. He made in the +290HP range with the emanage as the ems.

 

Id go with TIAL for wastegates, they make quality stuff.


Also be ready to drop a good dime not only for the wastegate, but the labour involved

 

If I do recall..Manuel from Puerto Rico was the first to do an external wastegate.

If my memory serves me correct, he was able to hit 273 whp ..with his setup and emanage at a slightly higher than AFR than I would like. 12-12.2.

Like Bindon said, the cost of the wastegate is not all that bad but add the labour for fabrication and it can get a bit pricey unless your Mazdamaniac who fabricates their own setups!

 

How big wastegate would be recomended with the greddy setup? Links?

 

...come on guys! All I´m asking for is a suggestion for what size of a wastegate, or what wastegate to use with the greddy setup?

 

In case you didn't other posts.. they said there are pics in another thread called "GREDDY CAI". Use the search button.

I used the Tial 46 mm but it is quite difficult fitment wise to put in but is spec'ed out by Tial to be able handle the high heats of rotary exhaust.

 

Here's Hybrid-RX8 approach from the GREDDY CAI thread:

"I have a 0.5 bar spring in a Tial 46MM wastegate. Yup, it's a gigantic wastegate and took quite a bit of work to reroute the piping and fit everything as we all know the spacing is VERY VERY tight already as is."