Turbo sizing, deeper discussion
- Thread starter oldestof11
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Kill
New member
Good info, so lets say for instance you are using 2 box s366s as primaries. If you switched to 68/76 turbines with the same compressor, it should be more efficient. Or possibly going to 71mm compressors and keeping the 73/80 turbines? I suppose the choice would depend on how much fuel you are pushing through them.
Smokem
Turbler
This is a good example, for instance a few of the WOP/Pius triple turbo setups I have seen use two K31's as the low pressure stage, having a 71/94mm compressor and 71/82mm turbine, which is maximizing the compressor inducer for the given turbine size. HTT also offers/offered the BW S300 with a 71mm K31 compressor wheel and the 73/80mm turbine wheel, it was quite potent for it's size and was what Ryan Tucker used on his '23 Altered.
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murphy41
New member
Weston,
On the WOP/Pius K31's, and the GTX4508s on Chris setup, how much effiency and performance change is lost or gained using the same compressor/turbine size and running it as a high pressure stage or even a single? Assuming the pulses would be much different on a manifold versus being primaries.
On the WOP/Pius K31's, and the GTX4508s on Chris setup, how much effiency and performance change is lost or gained using the same compressor/turbine size and running it as a high pressure stage or even a single? Assuming the pulses would be much different on a manifold versus being primaries.
Str8jacket
New member
If you don't have unlimited fuel and control options like joesixpack ie everyone elseLOL well mech fuel pump people, is there ever a benefit to having the size difference between turbine and compressor?
For example if with a given turbo the compressor has enough wheel for the requirements but it is choked on the exhaust size would the option to go up a wheel size on the turbine and keep a tighter a/r be better than just going up in an a/r size on the original turbo?
I have been thinking that big turbine small a/r is better than small turbine big a/r for my future projects, am I way off?
For example if with a given turbo the compressor has enough wheel for the requirements but it is choked on the exhaust size would the option to go up a wheel size on the turbine and keep a tighter a/r be better than just going up in an a/r size on the original turbo?
I have been thinking that big turbine small a/r is better than small turbine big a/r for my future projects, am I way off?
Smokem
Turbler
I should clarify, either the low pressure or high pressure turbo in a two stage setup can benefit from maximizing the compressor size for the given turbine size. The issue with this practice in a single stage setup is surge, in a high pressure situation such as diesel engines commonly see it is exaggerated.
Both can relatively achieve the same goal, but as the graph shown on the previous page illustrates, the answer to the question bigger wheel or bigger housing depends on the cubic inch of the engine in question.
murphy41
New member
This is what I was curious about. Its harder to match the compressor/turbine wheels like above in a single stage without falling right on the surge line. With that being said, how much does opening up the MWE groove actually affect the surge line itself, versus the actual MAP overall. Assuming the MWE will affect the surge line some, Im curious how much ?
Smokem
Turbler
That would most likely depend on the groove's location and size, but I wouldn't expect miracles.
murphy41
New member
This is more or less what I was curious about. I figure surging comes from compressor load vs turbine load and the MWE groove wouldn't have much affect on them.
Headcase98002
New member
With conversation leading to MWE grooves, is it needed in a primary?
Great topic. As mentioned earlier most O.E. turbos are designed for emissions restrictions. It is still interesting the combinations the "box turbos" where intended for.
179079 for 7.6l 62 ind 84 exd 68mm
177283 for 8.1l 63 ind 88 exd 68mm
177443 for 5.9l 57 ind 83 exd 65mm
holeset _he351 60 ind 86 exd 60
holset hx40 8.3 60 ind 86 exd 65
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SmokinCAT
Cheap and Easy.
The HT4 is closer in relation between comp inducer and exh exducer are relatively close in relation compared to what he listed.
Leiffi
New member
It's opposite to compressor so lower trim, like HT4 or S4, works with old large manifolds that make more backpressure and lower exhaust velocity. High trim turbines like HX60 97/92 need modern tight manifolds with high exhaust velocity and low backpressure.
Chrisd91
New member
Weston, instead of pestering you for tidbits of information, is there some reading you would recommend for further education beyond basics most can pick up from reading this and other forums? There was a link posted to a book earlier in this thread, but are there any you would personally recommend?
cummins939
New member
A very common twin setup is the 66/73/.91 or 14cm paired with an s480 using a 96/88 Exhaust wheel and 1.32 housing. Most can break 950hp with this setup and some have made 1100+ on a commonrail with fuel only. My question is, do you think running the same 66 with an s480 with an 87/80 turbine and 1.10&t6? Would make more power? Or even 66/68/.91 with an s480/87/1.10t6?
murphy41
New member
In my opinion with some of the setups we've tried, instead of dropping turbine wheel and housing sizes. You'd be surprised at how badass a 480/96/1.10 T6 runs. Moves the power curve down in the RPM range a little and has a fairly smooth power curve.
SmokinCAT
Cheap and Easy.
I proved this to myself this past week, tried to different turbos on my 3406, first was a garrett tv8511 with a single entry 1.39 housing, pretty similar in spec to a GT5518 and the performance was less than desirable, then switch to a HC5 holset setup as would have came on a K series, E trim turbine and 40cm twin entry housing.
This turbo is almost as responsive as the S410 that used to be on the engine, and was rather surprising to me.