Take these two pictures for example. Let's say everything is equal between two turbos except for the hotside. Does the 5 bolt housing on a turbo such as the GT35R make less power with an internal wastegate than a 4 bolt without the internal wastegate? I am wondering if I should switch up my kit. I am going to be upgrading to a T67/37R. I want maximum hp and want to do this the right way. Thanks.

Comparison Pics:

5 bolt w/ wastegate


4 bolt w/out wastegate

 

4 bolt housing are known to make a very littler more power

5 bolt housings have the internal wastegate option

 

Anyone that wants to make good power goes external WG.

 

There will be alot involved for me to have my manifold modified and alot of extra expense in getting the 4 bolt hotside to work. If I can make quite a bit more power this way, then it might be worth it. I just wish I new how much of a difference there would be.

 

hate to go off topic. but what turbo is that?? looks like a 3582. if so can u take a pic on the compressor side. i want to see your compressor cover. thanks bro

 

Which one? They are both Garrett/Precision turbos. Ones is a gt35r the other is a pt67/37r.

 

many 5 bolts are 2.5" outlet, where as many 4 bolts are 3" outlet. (not all of course)

 

hum. if you dont mind both of them. if i had to pick one though i pick the 5 bolt one. thanks bro.

 

I have heard there are people that have picked up about 40whp going from the 5 bolt to the 4 bolt, but i believe this is at like 30+ psi.

 

I doubt the 5 bolt makes less power since both AMS and Buschur run 5 bolts.

 

I did see that Buschur's kits DO NOT have the internal wastegate on the turbo though. That is a big difference also.

 

The OP can run a wastegate off the O2 housing like AMS does with their setup. They claim it makes the most power while offering great boost control and I don't doubt them based on their successes.

 

As requested, this is the front of the GT35R



The PT67/37R

 

Not one to argue with success, however, I am having a tough time comprehending the effectiveness of your postulated, post-turbine housing wastegate location. But, of course my conceptual powers are probably hobbled by the fact that I am thinking in terms of a stock-like turbo setup as well as the effects of this drat 7.9% brew.

 

5 bolts you mostly run 38mm wastegates and 4 bolt is a newer design hotside that weighs a little less and mostly 44 mm wastegates are ran. The t3 5bolt design was used on older vw's turbo diesel....