do turbos kill mileage? bypass for mpg?

[Firestarter]

Originally Posted by oil pan 4

I didn't need an STS system to add my turbo.
Since the turbocharger is a heat engine why would I want to remove it from its heat source?




That is what I have and yes they do it better.

Turbos use drive pressure... more heat means more drive pressure but they still function normally. You just need to use a properly matched housing.

Its easier... also the air density is greater from an sts system so it compensates for the lower thermal energy at the turbine. Plus heat isn't in your engine bay.

Biggest problem is sending turbo oil back via scavenging pump.


Also in regards to BMW... they use rather small turbos capable of boost under 2k rpm stock. I'd bet they keep their waste gate open at cruise to help their mismatched turbine housing.


When I went compound turbo on my CTD... I gained another mpg and lost absolutely nothing at high altitude... but a hundred spool rpm

[oil pan 4]

The turbocharger is a gas turbine.

Originally Posted by Firestarter

Turbos use drive pressure... more heat means more drive pressure but they still function normally. You just need to use a properly matched housing.

Its easier... also the air density is greater from an sts system so it compensates for the lower thermal energy at the turbine. Plus heat isn't in your engine bay.

Removing the turbo from its heat source makes it function more like a very inefficient air tool.
Dencer exhaust going through the turbine housing doesn't compensate for anything. Less heat is lower energy which gives you less power to be had.
Over all drive pressure is something you don't want. Extracting work through differential temperature is how the engineers figure it.
There are better ways to deal with under hood temperature problems than adding more piping for the intake and a lengthy run of pipe containing drive pressure.

Originally Posted by Firestarter

Biggest problem is sending turbo oil back via scavenging pump.

The established way of doing it works great for me, I see no need to try and reinvent the wheel.

[Firestarter]

Originally Posted by oil pan 4

The turbocharger is a gas turbine.



Removing the turbo from its heat source makes it function more like a very inefficient air tool.
Dencer exhaust going through the turbine housing doesn't compensate for anything. Less heat is lower energy which gives you less power to be had.
Over all drive pressure is something you don't want. Extracting work through differential temperature is how the engineers figure it.
There are better ways to deal with under hood temperature problems than adding more piping for the intake and a lengthy run of pipe containing drive pressure.


The established way of doing it works great for me, I see no need to try and reinvent the wheel.

I meant the remote turbo setup having oiling problems over the normal gravity return of the regular setup...

The exhaust still has heat. And drive pressure is a must. Your turbo will surge if the drive pressure drops below intake pressure. And sts may not have as much exhaust velocity... but it uses a smaller nozzle to compensate for it and the air density is greater from all the extra intercooler piping.

Never mind. I'm assuming its the he351... they make titanium turbines and billet batmo wheels for that turbo that should increase its efficiency by a lot.

I ran a race cover billet s300 over a s400 compound setup on a 70psi Cummins. Made over 700rwhp and 1500ft/lbs... ran 18* of timing and up to 4000rpm. Nothing like a Cummins!

[oil pan 4]

Originally Posted by Firestarter

but it uses a smaller nozzle to compensate for it and the air density is greater from all the extra intercooler piping.

Yes STS was recomending much smaller A/R housings. I remember one application I read about they were recomending .48 A/R turbine housing to V6 camaro guys, a group that normally runs .7 to .8 A/R turbine housings with T4/T3 hybrid turbos.

Originally Posted by Firestarter

Never mind. I'm assuming its the he351... they make titanium turbines and billet batmo wheels for that turbo that should increase its efficiency by a lot.

Do you know how much one of those after market Titanium wheels costs?
I started to look into it and when I got my first hint that it was over $400 I stopped looking.
It would be nice.
But I would have to see a compressor map first, I barely use the lower half of what that turbo compressor wheel can put out.

Originally Posted by Firestarter

I ran a race cover billet s300 over a s400 compound setup on a 70psi Cummins. Made over 700rwhp and 1500ft/lbs... ran 18* of timing and up to 4000rpm. Nothing like a Cummins!

Yes they are.
Most of the GM 6.5L and 6.2L guys are picking used cummins take off turbos (removed for up grade, sold on ebay) and sticking them on our builds.
They leave the factory with great turbos.
Building one of our motors and sticking a GM factory GMx serries turbo on there is pretty much unherd of now.
They are usiing mostly HX35, HX40w, H1C1? and a few are HE351VE (the VGT scares off most people).

[turbobob_01]

I own a 2011 Cruze 1.4L turbo with auto trans. and have been playing with it a little bit, mostly attempting less boost by the addition of counter springs and hoping for more MPG. So far I have not seen any type of improvement over the stock setup. I baby the car and even pull it into neutral when coasting to avoid the factory normal downshifting of gears. I think I will try some simple aero mods instead of messing with the turbo anymore. What it is is what it is. I get around 36.5mpg. These are 'real' numbers. My drive is 50 miles one way and back everyday with minimal stop signs. No high speed driving, 60mph. top speed.

[Firestarter]

Originally Posted by turbobob_01

I own a 2011 Cruze 1.4L turbo with auto trans. and have been playing with it a little bit, mostly attempting less boost by the addition of counter springs and hoping for more MPG. So far I have not seen any type of improvement over the stock setup. I baby the car and even pull it into neutral when coasting to avoid the factory normal downshifting of gears. I think I will try some simple aero mods instead of messing with the turbo anymore. What it is is what it is. I get around 36.5mpg. These are 'real' numbers. My drive is 50 miles one way and back everyday with minimal stop signs. No high speed driving, 60mph. top speed.

I would suggest not altering your boost management system.

And coasting in neutral usually isn't good for automatics.

Turbos don't suck down energy like more rpm does generally. Its like engine displacement on demand. And with a 1.4l you're going to want that baby snail pumping air... that's what it was designed for. To cruise with a 1.4l and accelerate with like a 2.5l.

But messing with a turbos hardware and not tuning for it can cause engine failure.