Downpipe with external WG on stock turbo
 

I was visiting ATP Turbo's website and came across their downpipe for the Evo X. It has a divorced wastegate design for the stock internal wastegate, but also allows you to swap in an external wastegate to use on the stock turbo.

It may work pretty well, it may not make any difference, but +1 for another option available {thumbup} I think it would probably work better if the hole for the stock wastegate was ported larger, and it may be even better on higher flowing, stock replacement turbos.

Thoughts? Opinions?

http://www.atpturbo.com/Merchant2/me...egory_Code=BCS

https://img526.imageshack.us/img526/...pdownpipe2.jpg
https://img526.imageshack.us/img526/...pdownpipe1.jpg
https://img14.imageshack.us/img14/1391/atpdownpipe3.jpg
https://img151.imageshack.us/img151/...pdownpipe4.jpg

looks nice

Looks badass

looks like4 a great peice want to see how it works

x2

now thats what im talking about! i would like to see a pic of it in 'external' mode. do you just unclamp the t-bolt and rotate the wastegate to get it that way??

i wonder how the numbers look compared to something like the AMS downpipe that has a much larger opening though..?

It looks like a very clever design and good upgradability down the road. If the turbo outlet is the same diamater as the DP then it's fine the way it is assuming it widens out to 3" right after the flange. The wastgate doesn't really need to be all that big to bypass enough exhaust gasses. The flapper on the GT30 may even be slightly too big as the boost is tapering for me 2 psi even with a Forge WGA.

^ true.

so help me understand this a little better fellas. how exactly would you make it work with the WG actuator on the turbo and then the one on the DP??

you would have to remove the flapper and part of the flapper arm from an internally wastegated turbo to use the external option

Looking at the pictures again, it looks at though the actual opening in the flange matches the size of the turbine housing outlet (2.5" maybe?), but leads directly out into a 3" pipe.

Nice looking downpipe.

what's the pricing with this new toy? lol

If there were no interference issues you may even be able to wire the internal wastgate flapper open, or adjust it slightly closed and use it as a valve of sorts to potentially reduce taper at higher RPM's assuming you weren't inducing boost creep at other RPM's.

Here is ATP's response to me after asking them if they have a dyno sheet and the reason for it being so expensive:

"Very good questions.

As for this part being $900 and whether it's worth it. We'll ask that you look at it from a slightly different angle.

Our intention with this product is to provide an 02 housing/downpipe assembly that is well made, performs well, and is price competitive to the current market. Along with that we are able to provide the added feature of ability to go to external wastegate (when the customer is ready to do so). As you can see, we tried to do things a little different and provide as much bang for the buck as possible where it makes sense and build in enhancements that set our products apart from some of the others. So it's really a $395 part with the ability to transform into another application with ease.

As for the gains. Quite honestly, we've only dyno'd tested this on our own EVO X test car and it happens to run a Garrett GT3076R. The gains are so huge (upwards of 50HP) that we would not dare publish this as a "HP claim". We will not put a HP claim on the stock turbo application and expect that those who research some of the other similarly made downpipes can derive at the approximate gains. Should be real close to some of the others in terms of power difference over stock.

As far as the added cost of the external wastegate. We would not want anyone to switch over to external wastegate unless they could justify it. The feature is there so that "if and when you're ready and you feel that you need it, it's available". We feel, the convenience and cost associated with the switch to external wastegate is an order of magnitude cheaper and simpler if you already own our downpipe, to make that switch. In our experience, once you determine that the external wastegate is necessary, there is no substitute for that need. The difference in ability to control boost is undeniable. In a lot of high boost application, it can save an engine from grenading due to bosot chasing. However, this may not be readily apparent to most people and until they get to that point where they feel they need, we like to have that option available. We put the external wastegate on stock turbo in the "advanced user" category and most people are not there right off the bat.

Now you understand our intentions. Hope that is straight up enough for you and if you have any other unanswered, please feel free to let us know!

Thanks again for posing the questions!"

The downpipe itself is $395 and I'm sure you could do some shopping and find a Tial wastegate for a lot cheaper than they sell them for.