30-32 psi goal

[TurboJ]

Sorry, but...

...I really must bring up the subject of PSI vs hp. Boost pressure alone doesn't mean one single thing. That is a 100% fact even on gas engines,
and when we're talking about diesel engines, the fuelling question makes the equation far more complicated still.

Let's say you have optimum fuelling on each case; then it's the question of air AMOUNT that enters, and exits, your engine, that makes you power.
You have to understand that turbos are designed to push more air into the engine, not just raise pressure per se.
A small turbo will flow much less at 30 psi than a large turbo will at 30 psi.

I will give you and example ( and even if it's for a gas engine, the point can be well seen )
I have seen three 2.0 litre 16V Saab engines, that all had an equal 270-280 horsepower. One had original Mitsubishi Te05-12B turbo, one had a trim 60 Garrett T3/T4E hybrid, and the last one had a medium-range Garrett T4. Boost pressures at max power were 1.7 bar (25 psi), 0.9 bar (13 psi) and 0.7 bar (10 psi) respectively.
Pressure means nothing, it's the amount of air that the turbo can ram into the combustion chamber, that makes all the difference.

Of course, we should also talk about intercooling efficiency, but the point here is that it's a completely different thing whether you talk about boost pressure or horsepower.
Modern turbos also have better efficiency, which means they needen't necesserily be bigger than the old '80s units we're used to, in order to make more power. The better
designed housings and wheel shapes, along with improved bearing sections, mean they can flow more liters at a given pressure, resulting in more power ( while they can better use
the exhaust energy to allow lower boost treshold and still maintain adequate exhaust flow and thus lower back pressure ).

VNTs have come along precisely because when you want to have more power, you need a bigger turbo, not just more pressure. The whole point of the VNT is to make a bigger turbo act small when you want it to, and act big when you want it to.

Of course, if you don't change your turbocharger, then yes, up to a certain point, you can have more power by increasing boost pressure. Still, I very firmly believe that whenever you want to add any significant amount of power to a turbocharged engine, the first thing you should always do, is get a bigger turbo (obviously on a diesel, you also need a special pump).
This is true because there is almost always very little room for reliable power increase using the standard turbo. When you force more air through it, the air will be getting too hot (that's when you're pushing the turbo above it's efficiency map) and you actually lose power through that. And you'll destroy the turbo in no time. And you'll crack your cylinder head with heat and snap your con-rods because of excessive back-pressure. Power is only fun once it's reliable, and for that, you need your turbo AND your engine operating at safe pressures and safe heatloads. With the right turbo and right fuelling you can achieve just that.

Yeah, it's a long whine, but I've seen these psi targets so many times.....  You should have a hp target, not a psi target!!!

[brandonfast]

ok so is 160hp doable on a 1.6td? thats my goal around. 200 just wont happen with a 1.6 bottom end and 1.6 head without spending loads of money.

[Rabbit on Roids]

im not controlling my vaines at all, it would spool alot faster if i had some sort of control.

[TurboJ]

ok so is 160hp doable on a 1.6td? thats my goal around. 200 just wont happen with a 1.6 bottom end and 1.6 head without spending loads of money.

For 160 hp, you don't need to do very expensive modifications; all you need is to upgrade the turbo, a good pump with 10 mm plunger head minimum, a free-flowing exhaust
and a good intercooler. You don't have to make any internal mods to a stock 1.6 TD engine for this kind of power, if it's in good condition. The reliability will come through a
well-sized turbo and well-adjusted fuelling. And once your intake and exhaust systems flow well, there will be less flow resistance which will require less of the turbo and make
the same power with better reliability. You might also want to change your intake manifold. Gasser manifolds are plentiful and cheap, while reasonably well designed.
A VNT turbo is of course one choice, but you may face problems with your connecting rods. A traditional turbo should have around 40-42 mm intake, and 46-48 mm exhaust sizes, but this is largely dependent on the type of turbo you're looking at. A Holset HX25 or 27 , Schwitzer S1bg, Garrett GT25 series etc. would be good options. While changing the turbo you will need to modify the exhaust manifold, so that's a good opportunity to upgrade the manifold alltogether - the stock one isn't the worst, but you can improve spool-up massively if you use a mani with less internal volume.

[Street Toys]

Well said, is this Johan?

[4wheeler]

Compound is not for anything less then 50psi??

K14 set at 15psi fed by a T3 set at the same should be around 25-30psi ish.
the biggest benefit would be no lag and plenty of top end volume.
Just make sure you have an external wastegate from the mani to the T3
Wouldn`t want the K14 heating up becasue it won`t allow enough volume
through it. If you had access to the K24 that would be a better choice for the large turbo.
Although if you re running the setup in a MK1 then try the K03-K24 setup.

[Rabbit on Roids]

Compound is not for anything less then 50psi??

K14 set at 15psi fed by a T3 set at the same should be around 25-30psi ish.
the biggest benefit would be no lag and plenty of top end volume.
Just make sure you have an external wastegate from the mani to the T3
Wouldn`t want the K14 heating up becasue it won`t allow enough volume
through it. If you had access to the K24 that would be a better choice for the large turbo.
Although if you re running the setup in a MK1 then try the K03-K24 setup.

but you have the ability to make 30 psi with a single turbo, and not even really be pushing it to its limits. say the high pressure turbo is making 22 psi, and the low pressure turbo is making 15, you dont just add the 2 numbers. compounding turbos doesnt add the air, it multiplies it. so those two making 15 and 22 psi, really will be putting out about45 psi probably. either way, i wouldnt run compounds unless i were racing, or needed 40+ psi boost.

[brandonfast]

im picking up 2 gt2056v's today. i found out usedturbos.net is located right down the street from me and hes got 2 of them for a nice price.

[rodpaslow]

Honestly if you are only planning on running 15 psi or less, then the stock 1.6TD turbos are actually too big.  You would not lose anything and you would gain boost 1,000 rpms sooner if you went with a K14.  Going even larger would gain you absolutely nothing except lag.  The boost is currently being controlled by the wastegate on the turbo.  You can easily add a manual boost controller.  Lots of info on the site and they are mechanical, so there is no wiring to do at all.  A bit of boost line plumbing, tho.  If you want to get above 13 psi or so, you'll need to disable the BOV.  Again, plenty of info and description on the site.  The search is your friend.

Above was said recently, and I want to make sure I understand.

I've read you could have the same horsepower output from three different turbos.
If these are all at the same rpm, the largest of the three will allow more exhaust flow, turn the slowest and flow more air into the combustion chamber because it's allowing more exhaust through with less back pressure.  Is this usually the case?

I have a T3 I was planning on putting in my 1.6 TD (stock t3), but I'm not sure I'll get what i want after reading this.  I'd like to have 140+ hp with a max boost of around 20 psi.  Is this do-able with a stock T3 (Canadian TD)

Thanks for any help!

[4wheeler]

compounding turbos doesn`t have to make crazy boost pressure, just set the turbos at a lower PSI setting.
The BIGGEST benefit from compounding turbos would be the HP and torque curves are more flat with no real peaks.
The small turbo prevents lag and provides the right amount of airflow at lower RPMs.
The larger turbo provides suplementary volume at higher RPM.
Of course when the smaller one is set at 15PSi and the larger one set at 10PSi you ll get a "compound" effect.
Who wouldn`t want 30PSi of boost anyhow? Another benefit is the fact that both turbos are not anywhere near their max capabilities, meaning a lot less heat. In turn, means one can beat the hell of of the vehicle without fear of grenading the turbo(s)

Engine RPM range 900-5500
(K14) power range is 25psi(depending on vehicle etc..) 1200-3500 After 3500 it restricts flow and creates heat not providing the volume of air required. 25psi is pushing this turbo outside of it s efficiency range=more heat.
(k24) power range is 25psi(depnendant on vehicle etc..) 2800-5500 Before that, is no/low pressure (lag)

compounding them...
These are arbitrary number.
Set the K14 at 15 PSI and the K24 at 15PSI
At about 2200RPM the K14 will make 15psi and the K24 will feed the K14 10psi
the 10psi that is delivered to the k14 will be further compressed another 15 times providing 30psi
This is where volume comes into play.. The k14 can provide enough volume at lower rpms becasue thats what its designed for. As engine requirments for cfm increase, so does the supply from the K24. Rather tricky math to get exact match for turbos and a lot of tinkering to get things set properly.
the benefits are well worth it IMO

You ll feed your engine with the cfm it needs at all rpms
less heat
broader power band
You can feel free to set the turbos at any PSI setting to achieve the desired results..
Just rememeber volume as turboj mentioned earlier. Volume is key..

[brandonfast]

who tried to swoop on my turbos today? haha the guy called me and said someone called him later after i talked to him about the same turbos and wanting to buy both. luckly the guy held 1 for me.