Lets talk turbos. T4 big singles

MorganY · Jan 30, 2014

KCTurbos said:
Yep... you can only go so far on a single. This is also why you don't want the little turbo to spool up and then gate around it to let the lp turbo run... that defeats the purpose of comounds IMO... you need to use the hp turbo to re-compress/compound the lp turbo air to increase the pressure ratio at which you can run the system

To a certain point. Sometimes you have to gate around the secondary pretty hard.

The less restriction your secondary poses, the more that statement works out.

Lots of factors, ultimately it helps to have a plan on paper first.

Pizza pig · Jan 30, 2014

by gating around a smaller secondary youre not really losing its efficiency, its staying in its efficiency range without over speeding. You want to drive that low pressure as hard as you can. Gate the secondary into the intermediate pipe and let that thing sing. Of course there will be a point where one is too small and one is too big.

KCTurbos · Jan 30, 2014

IMO everything everyone said is true... but it will all come down to sizing of the turbos/system...

the goal would be to get both turbos to run in the most efficient areas possible. Not just one or the other. If you could size them for both turbos to work in their most efficient areas of the compressor maps, create enough pressure, and not choke out the turbine side of things... then you will have a great proper setup.

MorganY · Jan 30, 2014

Greg@MPD said:
by gating around a smaller secondary youre not really losing its efficiency, its staying in its efficiency range without over speeding. You want to drive that low pressure as hard as you can. Gate the secondary into the intermediate pipe and let that thing sing.

Exactly.

smoker00 · Jan 30, 2014

KCTurbos said:
Kinda... you could theoretically size them right and not need a gate. But I think gating to maximize the efficiency of the system by using a gate would be the best. But not to shut down completely one turbo... Hope that makes sense.

Sorry for the derail... I will try to stay out of the thread a little and let other people comment. Threads like this usually bring out a lot of good info. :thumbsup:

My apologies also sorry about mucking it up a bit..

Josh@DirtyDiesels · Jan 30, 2014

So now that we're on the topic of compounds, what kind of setup do you guys think I could potentially run? Maybe even keep the 75 as the high pressure

MorganY · Jan 30, 2014

dzlpwr said:
So now that we're on the topic of compounds, what kind of setup do you guys think I could potentially run? Maybe even keep the 75 as the high pressure

91mm low pressure

Josh@DirtyDiesels · Jan 30, 2014

MorganY said:
91mm low pressure

This sounds appealing! And then the waiting game until it goes BOOM

smoker00 · Jan 30, 2014

How about one of the EFR's I don't know much about them but they spool super fast.. you have to watch it so you don't over speed it.. 62 64mm maybe..

and if the 75 isn't right put a 80 wheel on it or something like that..

Josh@DirtyDiesels · Jan 30, 2014

smoker00 said:
How about one of the EFR's I don't know much about them but I hire they spool super fast.. you have to watch it so you don't over speed it.. 62 64mm maybe..

and if the 75 isn't right put a 80 wheel on it or something like that..

What, an EFR as the HP? IIRC the largest EFR charger has a 67mm compressor inducer.

smoker00 · Jan 30, 2014

dzlpwr said:
What, an EFR as the HP? IIRC the largest EFR charger has a 67mm compressor inducer.

Yes that's what I was thinking.. HP charger

How much boost are you making with that 75?

Josh@DirtyDiesels · Jan 30, 2014

smoker00 said:
Yes that's what I was thinking.. HP charger

How much boost are you making with that 75?

Right around 50psi. I think I have a small drive pressure leak at the moment that I need to address though.

smoker00 · Jan 30, 2014

Boy that not to bad..

What size turbine/mm and ar.

Josh@DirtyDiesels · Jan 30, 2014

smoker00 said:
Boy that not to bad..

What size turbine/mm and ar.

t4 divided, .90ar housing, 83mm turbine.

BlueWaffle · Jan 30, 2014

Greg@MPD said:
by gating around a smaller secondary youre not really losing its efficiency, its staying in its efficiency range without over speeding. You want to drive that low pressure as hard as you can. Gate the secondary into the intermediate pipe and let that thing sing. .

that's exactly how mine is set up

KCTurbos · Jan 30, 2014

sent a PM instead

Josh@DirtyDiesels · Jan 30, 2014

KCTurbos said:
sent a PM instead

To who? me?

KCTurbos · Jan 30, 2014

dzlpwr said:
To who? me?

Nope... it was to someone else. I was trying not to get too off topic in your thread

Josh@DirtyDiesels · Jan 30, 2014

KCTurbos said:
Nope... it was to someone else. I was trying not to get too off topic in your thread

Word. No worries.

Josh@DirtyDiesels · Feb 4, 2014

just for reference I took a quick vid the other night of spool time cruising on the highway. This was doing just over 70 at 2k rpm as seen in the vid. Eased into it maybe a 1/4 throttle and you can see the boost come up to about 10psi on the factory gauge. Then went to about half throttle and the boost climbs to about 25-30psi. Just so you guys can see where I am at now with it. http://www.youtube.com/watch?v=cZTsDN0YBP0