Balor_Gr

Hi there.Im located at Greece.And im about to buy a new
holset turbo for my d16.Its the "european" HX35 SUPER (I only managed to find this turbo at europe)
Target hp is 350-420whp.


Option A
Compressor is inducer:54mm exducer:77mm(7blade)
(Something like t04e 50 trim)
T3 single entry 8 cm2 (= 0.57 a/r?)
Turbine inducer 65 exducer 55mm
like a stage 3

Option B
Compressor is inducer:54mm exducer:77mm(7blade)
(Something like t04e 50 trim)
T3 twin scroll 12cm (=89 a/r?)
Turbine inducer 70mm exducer 60mm
*This turbine is something like "stage 4" cause stage 5
wheel is 72mm/62mm

Option C
compressor inducer 58mm exducer 78 mm(7blade)
T3 single entry 10cm (=0.73 a/r?)
turbine :inducer 65mm exducer 58mm


Whats the best option taking into account i WILL use divided manifold with option B.

Which will spool faster and is it possible for option A to manage 400 to the wheels?

Thanks for your time guys.
I really need this info.

secretcitizen

Option B with twin scroll

see link for undivided vs divided dyno
http://www.d-series.org/forums/force...xperience.html

Balor_Gr

Yeah i know twin scroll helps a lot but in my options:

compressor wheel size A=B<C
Turbine wheel size A<C<B

So if i use thwe twin scroll setup i will also be using a biger turbine wheel .

Im confused big time.

secretcitizen

The smaller housings on the other two might become a restriction with the larger compressor.

12cm undivided ≠ 12cm divided

Balor_Gr

Yeah but isnt it (divided a/r)x0.6=undivided ?
So the 12 divided is about 0.53 a/r

Or im i wrong?

secretcitizen

This is where someone else might need to chime in. I understand that sizing; cm to a/r, and divided to undivided is complicated. It might add up to be one thing, but on the car it is another.

TheShodan

iTrader: (14)

Option A. And its only a divided housing, and not a "twin scroll" for heaven's sake. That won't help you in the slightest.

This is a common setup. Using a larger exhaust wheel will increase torque, but no rotational velocity to "spool up", especially in a divided housing with such a large volute like 12cm.. Especially on a horse like the d16.

Stop planning your build like you are some sort of tractor or truck.

secretcitizen

Excuse my ignorance, but what's the difference between ts and divided housing?
I couldn't find any explanation on a quick search.

*edit*
Dug a little deeper

Twin scroll has two physically separate housings


Divided housing is one housing that is divided.

TheShodan

iTrader: (14)

You just stated the differences. Good!! But the divided housing is not separated all the way down the volute channel. The holset divided housings are like the second illustration that you provided, and not like the first (which is the EFR design).

By Definition- Twin-scroll turbochargers have two exhaust gas inlets and two nozzles, a smaller sharper angled one for quick response and a larger less angled one for peak performancethe exhaust manifold physically separates the channels for cylinders which can interfere with each other, so that the pulsating exhaust gasses flow through separate spirals (scrolls). This allows to efficiently recover exhaust energy and provide better scavenging, which decreases exhaust gas temperatures and improves turbine efficiency, reducing turbo lag.

Simple divided housings help with LARGER turbochargers and truck applications that are concentrating on lower end torque. That's why they are mainly in T4 configurations.



EFR Example



standard T4 "Divided" housing configuration, notice the volute is still a single size


In this particular case, he's better off with a more compact and efficient smaller wheel combination than putting hopes and dreams on too large of a turbine housing thinking that it is going to help responsiveness.

A divided housing is a necessity for a twin scroll configuration, but enough of a sufficiency to be called a twin scroll

Balor_Gr

Full race description on twin scroll:
About Twin Scroll: Twin Scroll turbo system design addresses many of the shortcomings of single-scroll turbo systems by separating those cylinders whose exhaust gas pulses interfere with each other. Similar in concept to pairing cylinders on race headers for N/A engines, twin scroll design pairs cylinders to one side of the turbine inlet so that the kinetic energy from the exhaust gases is recovered more efficiently by the turbine. For example, if a four-cylinder engine’s firing sequence is 1-3-4-2, cylinder 1 is ending its expansion stroke and opening its exhaust valves while cylinder 2 still has its exhaust valves open (while in its overlap period, where both the intake and exhaust valves are partially open at the same time). In a single scroll AKA undivided manifold, the exhaust gas pressure pulse from cylinder 1 is therefore going to interfere with cylinder 2’s ability to expel its exhaust gases, rather than delivering it undisturbed to the turbo’s turbine the way a twin-scroll system allows.


Ive read in the past that the is a difference between twin scroll and divided housings. But why i a divided housing + divided manifold wont help me ?
You sure .92 a/e is big for a full divided setup?

editI posted silmuntaneously with Theshodan.Damn i always thought that this divided thingy was all the way inside the housing..

secretcitizen

One thing you can enlighten me on.
If a holset dh isn't much help on a d16, how did it help out the guy in the link I posted?

Balor_Gr

I had the exact same question.

Also the whole INTERNET is filled with twin scrolls thats actually divided as the shodan said.

https://www.google.gr/search?client=...IJCY1AXiz4HACg

Big question here.DO we treat DIVIDED housings a/r as smaller a/r?
The multiply by 0.6 is still valid ???

secretcitizen

I think the majority of the internet's terminology is incorrect, and they're ignorant to the fact that there is a difference between the two.

I would consider to be what it's stated as. It is in essence just an .89a/r single scroll housing with a divider.

Balor_Gr

T4 Garrett .70AR , T3 Garrett .84AR, T3 18.5cm Holset, T3 16cm Holset, T3 14cm Holset


It seems holset divided housings are more squared along the volute.Maybe more efficient??

wantboost

iTrader: (2)

thats more or less just a casting feature, as well as for space considerations on the application the turbo was designed for....

the one thing i've always wondered is while twin scrolls are physically divided (until a point in the volute) how does the smaller section affect such things as exhaust flow, egt, and backpressure for those cylinders that happen to be paired to that smaller volute?