madmikeismad
So mad
I see what you're saying. Typically yes, it'd just be straight bullchit. But for reasons I don't understand, in this case it's true.
Double batmo 66/74/.91 spool up?
- Thread starter STACKED
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I see what you're saying. Typically yes, it'd just be straight bullchit. But for reasons I don't understand, in this case it's true.
cummin get it
coal train
Better count them blades there hoss.
CR From Hell
Never Satisfied
Nah, the first is a 12 blade and the third is a 10 blade. Look at the pitch in the first, unless it's an illusion from the angle of the picture the blade seems to curve inward towards the top of the blade, creating more of a lip. Also there is a noticeable difference in the angle (not a straight line) from the hub to the outside of edge of the blade, almost like a staggered comp wheel design.
TMONEYDIESEL
Comp Diesel Sponsor
:hehe: :hehe: so ive got this S588 and it spools NO JOKE like a hx35.
Why should you purchase? Because Racetruck duh! :hehe:
Ah ha.. thanks. I completely overlooked number of blades.
straight 6 roar
New member
You posted this in the compressor surge thread last week: "The facts of how the setup works in the real World does not jive with 0.96AR." Interesting how you tout "facts" when it's convenient, and "real world" when not. Multiple people have stated that the difference in spool between a 66/73/.91 and 67.7/83/.90 is negligible. That is why I recommended it to the OP and for the reasons stated in my original post. Yes I understand they are different wheels.
Maybe if you could slap a 366 compressor/cover on a 83/.90 then it would spool slower, but this is not the case.
Also, my deepest condolences for being .01 off on the housing A/R.
Smokem
Turbler
You never chimed in with your boost/drive readings, I was waiting. Fact is in the real World many people have seen 2:1 boost/drive readings with the large turbine wheel in the T4 housings.
It would not spool slower, I thought you were against bro science?
If you notice in the second picture I posted which is the 73/80mm wheel, you will notice it is clipped, so initial spool may seem slower, but it will be easier to come back on boost pressure, this is similar to the Garrett design of the GT wheels. The real benefit of that turbine wheel is it can easily be used with a smaller housing, not as easy with the S400 frame.
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straight 6 roar
New member
I did, people use them on budget puller builds all the time. 2:1 boost/drive that'd be great. But I know you meant drive/boost; a 1.10 T4 will back up when the exhaust velocity gets high enough, but I have never seen it happen at 30 psi and doubt it will.
You just said the 74/83 wheel would spool slower, and made the assumption that the compressor is the exact same; in other words a 366 wheel. A magical 366 cold side and 74/83 hot side & CHRA would probably spool slower than a complete 366 unit.
But your assumptions fell through because the compressor I recommended is not the same as a S300 66mm. I guess everyone stating that the 67.7/83/.90 spools the same if not faster has been deluded of the truth. Also have you ever considered that a more efficient, higher flowing compressor of nearly the same mass & rotational inertia will propagate more air mass through the engine earlier and thus increase mass flow through the turbine earlier?
You're a very knowledgeable guy, but all you seem to do these days is call people out and criticize. I was helping out OP like most in this thread and then you make yet another condescending reply to my 1st post. And this happens to multiple other people as well. If you're going to keep making snippy, negative posts at least have a solid foundation for your argument.
Smokem
Turbler
Maybe I'm just a bully, maybe I've been working on turbos since before you had a driver's license, maybe I'm tired of people posting things based on what they heard on the internet.
Let me take a different approach, can you tell me what design difference accounts for the 67mm wheel's ability to create pressure at low shaft speed?
Smokem
Turbler
I forgot to mention the fact that I did take an hour out of my day riddled with condescending remarks and belittlement to post pictures helping explain why certain wheels offer certain characteristics, of course some people in this thread didn't get their feelings hurt. But you seemed to skip over that.
NickTF
Single turbo turd.
In general it sounds as if less blades produce more mass flow but at less pressure. More blades produce less mass flow but are more efficient at high pressure. There are so many variations to pitch and other dimensions though it is likely best to consult a map or experience/performance for each turbo in each application.
straight 6 roar
New member
About 4 posts later after you called me out and your statement fell apart when multiple people with 1st hand experience chimed in.
Maybe you can still learn a thing or two like the rest of us.
Obviously the blade geometry, do you really want me to 3D scan a wheel and dimension it for you? Because I won't.
This isn't even relative to the thread anymore, I'm done posting. PM me if you really want to.
Smokem
Turbler
Where the needle moves on the boost gauge, and when the turbo reaches full boost pressure are different, and whether or not it "spools" faster is only relevant when the definition of the term is described. Like I stated previously, the clipped 73mm wheel may feel a bit more "dead" at low shaft speed, but it will reach peak pressure earlier, and come back on boost earlier simply due to a more aggressive blade pitch and less rotating mass.
I know the answer, the question was; since you wish to post some out of your ass opinion as fact, do you know what on the wheel was changed?
All three of the following turbine wheels are very similar in size, and very commonly used, this should help show why I often say there is more to the wheel than just it's measurements.
How cute. Paint those blades to match your nails?
chris lang
New member
^ your about a dip**** aren't you?