Bullitt4110

iTrader: (31)

So I have a mp t76 q with a t4 flange and 4 bolt exhaust outlet that is 3". My question is since the outlet is 3" I would assume it would be a waste to make the downpipe any bigger than that? Or could running 3.5"+ downpipe and a reducer into the outlet potentially make a difference? I only want to build the downpipe once. Thanks.

Bullitt4110

iTrader: (31)

ttt...

TracyRR

iTrader: (8)

I have read that it should be 1.25 the size of the turbo outlet. 3 x 1.25 = 3.75".... Best of luck

Phil99vette

iTrader: (11)

I'd run a 3" to 3.5" cone to a 3.5" exhaust and external dump on the wastegate.

HydroStream6

iTrader: (16)

Going larger than a 3" might help a little but it won't make a night and day difference on that turbo by any means. If you have lots of room, go for it. If room is tight, going 3" won't really hurt you much, if at all.

Bullitt4110

iTrader: (31)

Thanks for the responses, I have a good amount of room so I'll look into the 3.5".

MillsMotorvation

That's the turbo I want to try, what you putting it on?

rotary1307cc

iTrader: (5)

1.25 the size of the turbine exducer.... so on a Q that would put you under 3.5"

Bullitt4110

iTrader: (31)

It's going in a 69 chevelle with a mostly stock 5.3 (probably do a cam) and a th400 with a converter. Nothing crazy but should be a fun street car.

Looks like it equates to about 3.3" so would it be better to do to 3.5 or down to 3"? Going with 3.5 would give me room to grow I assume?

rotary1307cc

iTrader: (5)

Run the 3.5 if you have the room

Bullitt4110

iTrader: (31)

Awsome, thanks.

ModularTurbo

iTrader: (14)

There are two "old adages" that pertain to turbo builds that come to mind after reading this:

1. "There is no such thing as too big of a down pipe"

2. "There is no such thing as too big of an oil drain"

With that being said 3" is the smallest I would use.

Bullitt4110

iTrader: (31)

Thanks, I am somewhat new to the "best" way to do things when it comes to turbos so I figured I would ask. I will go with a 3"-3.5" transition out of the turbo to a 3.5" downpipe. Thanks everyone for the help.

Phil99vette

iTrader: (11)

Cone engineering.com sells a nice inexpensive transition. They offer a MS one for $14 and a SS for about $40. They are very nice pieces.

Bullitt4110

iTrader: (31)

Ill look into it, thanks for link.

alradco

I'd run the biggest downpipe I could fit.

2165 Turbo Rail

iTrader: (1)

here you can see how I did mine. I went to a 4" dp..

Bullitt4110

iTrader: (31)

Ive been watching your tread closely and like what youve done. And yes we have a lot of room to work with.

2165 Turbo Rail

iTrader: (1)

Thanks. We are going to start working on it again tonight.

Bullitt4110

iTrader: (31)

awsome, mine is somewhat on the back burner due to most of my time and money going into the house I just bought but still working on it here and there.