Compounding om606 stock kkk k14 turbo with hx40/40w
Compounding om606 stock kkk k14 turbo with hx40/40w
10-24-2019, 07:01 PM
#5
(10-14-2019, 12:50 PM)Mh95e300d Hi guys.
As the tittle says, is it a good idea to use these two turbo in compound setup in my rhd w124 build.
The goal is to get atleast 450hp less laggy and least possible smoke. Already having dsl1 and the edc pump will be build with 7.5 meken elements.
Now I am still new to compounding setup so I know its not gonna be easy, also for such power levels even alone hx40 or bW sx257 is a good choice but as stated two main points above and easy availability of hx40. Thought why not try this route.
Looking for recommendations.
Thanks
If you search for compound turbo threads, you will see some detailed posts of how to think about it. Not many have actually done it or fully instrumented it after building it to see what is actually happening.
Full compound you would like each turbo to run PR 2. Sequential you would like the large turbo to provide maximum required air mass at PR 2-3. When you have to use PR=4 to cram enough air mass in to burn all the target fuel, your large turbo is too small.
So for a large turbo it makes sense to pick one that will give you enough air to burn whatever fuel you plan to put in (determined by target HP, BSFC, VE, Intercooler and turbo efficiencies) at a PR of 2-3. Practically, this means oversizing it a lot because you have to adjust for all those inefficiencies just mentioned, the last three of which have the effect of decreasing the air mass moving through the engine. The math is not that hard. From hp you use estimated bsfc to get the target fuel level, then use that to calculate required air mass, then adjust it upward by the inefficiencies and choose the large turbo.
The small turbo can be fairly tiny. It just has to provide enough air mass to the motor to get the large turbo spooled up. For the street you probably want it spooling very early. So pick a small turbine housing and a smallish compressor e.g. he221 or similar. The stock turbo is OK but the turbine is a very old design, so spool is less optimal. If hx30, no need for a Super 46mm compressor. Use the small one. Unless you plan to run both turbos all the time and not sequentially, in which case a larger small turbo is better.
To have any hope of understanding what it is doing, you should budget for some temp and pressure sensors before and after each compressor, egt, egp, intake manifold and maybe even wastegate postition and turbo shaft speed sensors. That is the dream. Could just put bungs everywhere and move a smaller number of sensors around as needed.
You will need one or two very large wastegates. 2x60mm perhaps. Both to bypass the small turbo at high rpm.
Have fun. Let us know how it works.
atypicalguy
10-24-2019, 07:01 PM #5(10-14-2019, 12:50 PM)Mh95e300d Hi guys.
As the tittle says, is it a good idea to use these two turbo in compound setup in my rhd w124 build.
The goal is to get atleast 450hp less laggy and least possible smoke. Already having dsl1 and the edc pump will be build with 7.5 meken elements.
Now I am still new to compounding setup so I know its not gonna be easy, also for such power levels even alone hx40 or bW sx257 is a good choice but as stated two main points above and easy availability of hx40. Thought why not try this route.
Looking for recommendations.
Thanks
If you search for compound turbo threads, you will see some detailed posts of how to think about it. Not many have actually done it or fully instrumented it after building it to see what is actually happening.
Full compound you would like each turbo to run PR 2. Sequential you would like the large turbo to provide maximum required air mass at PR 2-3. When you have to use PR=4 to cram enough air mass in to burn all the target fuel, your large turbo is too small.
So for a large turbo it makes sense to pick one that will give you enough air to burn whatever fuel you plan to put in (determined by target HP, BSFC, VE, Intercooler and turbo efficiencies) at a PR of 2-3. Practically, this means oversizing it a lot because you have to adjust for all those inefficiencies just mentioned, the last three of which have the effect of decreasing the air mass moving through the engine. The math is not that hard. From hp you use estimated bsfc to get the target fuel level, then use that to calculate required air mass, then adjust it upward by the inefficiencies and choose the large turbo.
The small turbo can be fairly tiny. It just has to provide enough air mass to the motor to get the large turbo spooled up. For the street you probably want it spooling very early. So pick a small turbine housing and a smallish compressor e.g. he221 or similar. The stock turbo is OK but the turbine is a very old design, so spool is less optimal. If hx30, no need for a Super 46mm compressor. Use the small one. Unless you plan to run both turbos all the time and not sequentially, in which case a larger small turbo is better.
To have any hope of understanding what it is doing, you should budget for some temp and pressure sensors before and after each compressor, egt, egp, intake manifold and maybe even wastegate postition and turbo shaft speed sensors. That is the dream. Could just put bungs everywhere and move a smaller number of sensors around as needed.
You will need one or two very large wastegates. 2x60mm perhaps. Both to bypass the small turbo at high rpm.
Have fun. Let us know how it works.
Messages In This Thread
Compounding om606 stock kkk k14 turbo with hx40/40w - by Mh95e300d - 10-14-2019, 12:50 PM
RE: Compounding om606 stock kkk k14 turbo with hx40/40w - by Mh95e300d - 10-23-2019, 04:15 AM
RE: Compounding om606 stock kkk k14 turbo with hx40/40w - by Sotvisp - 10-24-2019, 01:43 AM
RE: Compounding om606 stock kkk k14 turbo with hx40/40w - by barrote - 10-24-2019, 01:16 PM
RE: Compounding om606 stock kkk k14 turbo with hx40/40w - by atypicalguy - 10-24-2019, 07:01 PM
RE: Compounding om606 stock kkk k14 turbo with hx40/40w - by Mh95e300d - 10-31-2019, 01:37 PM
RE: Compounding om606 stock kkk k14 turbo with hx40/40w - by atypicalguy - 12-30-2019, 10:44 AM
RE: Compounding om606 stock kkk k14 turbo with hx40/40w - by Mh95e300d - 06-02-2020, 01:44 PM
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