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More Blades vs Less Blades

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jawar666

15+ Year Contributor
103
1
Jun 5, 2007
Costa Rica, Central_America
Hi community!

Just trying to get out of ignorance here! and hopefully somebody else might find the information collected in this thread useful...

With regards the number of blades used in turbos vs same turbos with less blades (either in the compressor side or the turbine side)...

I've seen threads about 7 blade HX35s to be recommended better than 8 blade HX35s.... and I've read lately in other forums about the 9 blade TD06SL2 turbines performing better than 11 blade TD06SL2...

Is that true? If so, what would the logic behind it?

Thanks!
 
More blades = quicker spool because of more blades grabbing air

Less blades = more airflow because of more surface area on the wheel
 
this is actually pretty complex subject. there are no simple answers. there are many factors in play. and some general characteristics of removing blades or adding blades would be reversed when talking about turbine blades or compressor blades.
 
I thought less blades = less surface area making room for more airflow???
 
The number of blades is not a big factor compared to the design and pitch of the compressor blades. I have had this specific debate with numerous people. When I got my new 67mm compressor wheel Looking into the compressor housing the newer wheel looks pushed in really really far due to its very aggressive pitch. most said and still think it would make less hp then my previous ett 67mm but its making way more power now.
 
In regards to the 9 vs 11 blade TD06sl2 wheels...when I sent my turbo in for a upgrade/rebuild I was actually persuaded to go with the 11 blade as he has had two people make right around 440whp on e85 around 28-29psi with the 11 blade while spool remained virtually unchanged from the stock cast wheel. Hope this helped some!
 
That's very interesting point! Just found in wikipedia what you just mentioned with regards pitch in propellers...

https://en.wikipedia.org/wiki/Blade_pitch

I wonder if pitch is the main difference between the HTA and the new HTZ wheels from Forced Performance...
the htz and hta compressor wheels are the same e.i. 67mm for the 3794r and super 94. The Super 94 just has a larger bearing cartridge, larger turbine wheel, and larger t4s housing
 
Their is definitely a difference in blade design from hta to htz. I just replaced an hta 76 with an htz 82. The most noticeable difference to me was the angle of the splitter blades.
 
Their is definitely a difference in blade design from hta to htz. I just replaced an hta 76 with an htz 82. The most noticeable difference to me was the angle of the splitter blades.
There is a difference because it's 2 different size compressor wheels .Not because it has different label. Same compressor wheel size hta to htz there is no difference in design. You can even find the info on their site. Go to super 94 and it states the 67mm compressor wheel is unchanged from the 3794r.
 
There is a difference because it's 2 different size compressor wheels .Not because it has different label. Same compressor wheel size hta to htz there is no difference in design. You can even find the info on their site. Go to super 94 and it states the 67mm compressor wheel is unchanged from the 3794r.
The sizes are the same, the aero tech is different from hta to htz. Straight from their mouths when I talked to them on the phone 3 times before I bought the 3582htz.

For instance, the hta76 wheel has been replaced by the 76htz wheel. They have the same inducer and exducer specs, but the blade profiles are different.
 
The sizes are the same, the aero tech is different from hta to htz. Straight from their mouths when I talked to them on the phone 3 times before I bought the 3582htz.

For instance, the hta76 wheel has been replaced by the 76htz wheel. They have the same inducer and exducer specs, but the blade profiles are different.
read it for yourself and state what it says LOL.
http://www.forcedperformance.net/PROD/NTFPSUPER94.html

it may be an updated wheel from the older turbos. 3586 etc. but not the more current ones which came with the updated design. they just changed the name from hta to htz.
 
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Exactly. The super turbos already had the htz wheels in them. Compare an hta wheel to an htz wheel, they are different.

Their website isn't usually accurate. It still lists my turbo as hta, when it's the htz aero.

Have you ever spoken with them on the Phone? It's a much more accurate way to get information on their products than the website.
 
Exactly. The super turbos already had the htz wheels in them. Compare an hta wheel to an htz wheel, they are different.

Their website isn't usually accurate. It still lists my turbo as hta, when it's the htz aero.

Have you ever spoken with them on the Phone? It's a much more accurate way to get information on their products than the website.
I have spoken to them numerous times and was told the hta 3794r has exactly same compressor as htz super 94.
 
So are you saying they decided to call the "new" wheels htz when they are actually old hta wheels across their entire product line? Or that some of their old hta turbos actually had htz compressors? Are all fp hta and htz compressors identical?

Is the "upgraded to htz aero" line just a gimmick?
 
So are you saying they decided to call the "new" wheels htz when they are actually old hta wheels across their entire product line? Or that some of their old hta turbos actually had htz compressors? Are all fp hta and htz compressors identical?

Is the "upgraded to htz aero" line just a gimmick?
Not a gimmick. Just think they updated some of the wheels still calling them hta then decided to change name to htz. But I'm not positive all the wheels were upgraded. I don't see dmers purchasing enough turbos to upgrade all the lineup so It wouldn't be cost effective to do so. Kinda of how pte hasn't changed their entire lineup to gen2.
 
As stated above, it's a complex subject because there are too many factors like improved aero tech which can effect spool, shaft speed, and airflow production. Look at the Small 16G vs. Big 16G...the Small 16G is capable of almost the same airflow because less rotational mass equals faster shaft speeds as well as quicker spool. Now once you factor the Evo III compressor into the equation, the improved aero tech of the Evo III wheel makes it flow even greater than the Big 16G despite being the same spec.

Generally, of two compressors with the same blade shape and physical size, more blades equals more airflow at lower boost (tighter compression, heats the air charge more) and less blades equals more airflow at higher boost (less physical compression, cooler air charge) with a slightly-quicker spool because the wheel is lighter...but the downside is you NEED to run a high boost level to make it worth having, meaning they can potentially be a dud at low boost levels because there's less physical compression.

A 6-blade HX40 makes almost the same airflow as a 20G 22psi...but the air charge the HX40 is generating isn't compressed nearly as much and is therefore more-usable...which is the benefit of using a larger turbo. On the flip side of that....at 38psi the HX40 is making almost 70 lb/min while the 20G is still stuck in the mid-40's if the shaft hasn't broken yet.


On the turbine-side of the turbo....less blades means higher turbine flow but slower spool because there's less blades to "cup" the exhaust flow. Some will argue that less blades mean the wheel is lighter and that would then offset the loss in spool, but I've had no direct-swap data to support this....meaning nobody's ever sent me a turbo that only received a turbine swap to the same size turbine with less blades- something else on the turbo changed as well.


So are you saying they decided to call the "new" wheels htz when they are actually old hta wheels across their entire product line? Or that some of their old hta turbos actually had htz compressors? Are all fp hta and htz compressors identical?

Is the "upgraded to htz aero" line just a gimmick?
I took the "Z" to be in response to the "Zero" and "Zephyr" turbocharger lineup...assuming they made some sort of change to improve the design in some way over the old wheels. None of the HTA turbos I've ever serviced were extended-tip, nor did they have a very tall tip height...so I speculate FP went back to the drawing board to gain a little high-boost efficiency despite the previous wheels working fairly-well.
 
Generally, of two compressors with the same blade shape and physical size, more blades equals more airflow at lower boost (tighter compression, heats the air charge more) and less blades equals more airflow at higher boost (less physical compression, cooler air charge) with a slightly-quicker spool because the wheel is lighter...but the downside is you NEED to run a high boost level to make it worth having, meaning they can potentially be a dud at low boost levels because there's less physical compression.

This sounds interesting to me... this info even might change somebody's mind when taking a decision for a turbo upgrade!
 
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