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I think for rebuild it could be a good option, procharger quoted me a touch over $1k for the impeller piece alone, something like a $150 "inspection fee" and then shipping both ways, and may as well do new seals while apart, and $100+ an hour for labor or something, and by the time I added it all up was going to be like close to $1800 to have it freshened up with new impeller. and can buy new one for not much more than that. but sounds like JB could be a cheaper alternative.
if there was solid, reputable data showing dyno gains with only his impeller as the sole change and no increase in IATs or reliability issues I think a lot of people would be interested in trying out his impeller (I know I would be) so hopefully he chimes in.
I emailed Mayhem Motorsports to see if they ever did the test and if they were willing to share the results of said test with me. The customer in question had a 1997 Corvette with a D1SC, and supposedly was going to have before and after results for the JB billet impeller. It would be an awesome piece of data to have, for sure.
yeah, without some whp test that is unbiased and with nothing else changed it's just not worth the time/effort/risk I think for a lot of people of trying one of these 3rd party impellers.
I emailed Mayhem Motorsports to see if they ever did the test and if they were willing to share the results of said test with me. The customer in question had a 1997 Corvette with a D1SC, and supposedly was going to have before and after results for the JB billet impeller. It would be an awesome piece of data to have, for sure.
if you ever hear back from Mayhem would be great to hear their results.
I reached out to JB and offered to dyno test their impeller with no changes but only an impeller swap, same car, same day, same tune afr/timing, and they said not interested. they also said the impeller is made by someone else (a turbo company) and they flow tested their impeller on a P1 and used some software simulation.
if/when some D1 tests come out though I'm very interested. if tests show this is worth >35whp with more top end then I'll get one and test it and report back here.
I'm sure there is equipment that measures airflow... like a flow bench. I'm sure you could setup a dc motor to spin the blower to a specific rpm and measure airflow and generate a cfm curve vs. rpm graph. I'd love to see that. I know that backpressure has an impact of airflow, but still, it would be interesting to see the curves of the two different impellers.
I'm sure there is equipment that measures airflow... like a flow bench. I'm sure you could setup a dc motor to spin the blower to a specific rpm and measure airflow and generate a cfm curve vs. rpm graph. I'd love to see that. I know that backpressure has an impact of airflow, but still, it would be interesting to see the curves of the two different impellers.
exactly, any data at all actually, or even a cfm/efficiency map would be amazing since procharger doesn't share those. If they really tested these they surely have one. confused why JB wouldn't share that?
People do not share this information because they are afraid such knowledge being public will negatively effect their profit margins, simple as that. It is the same reason people get all secret squirrel about their cam specs. Everyone is looking for a competitive edge over the next guy, instead of trying to advance the sport as a whole. It is called greed, and it is the plague of humanity.
I, personally, think keeping secrets is for people too afraid to be the best. If you are a shitty driver and are afraid that your cam specs will make the guy next to you win because he might be a better driver than you, then you are the problem. If you have a secret squirrel impeller design and will not share information about it, it is because it actually doesn't offer a benefit and it is all snake oil smoke and mirrors bullshit... or you are worried that sharing the specs of your impeller might give a new company something to use and improve on without going through the time/energy/money researching what you did. It all boils down to the bottom dollar and people being bitches.
In case you haven't noticed, I abhor such restrictions on information. Needless to say, if I hear back from Mayhem Motorsports about their D1SC JB impeller test, I will definitely share that information here.
I didn't read this whole thread, but there are a few points to make:
1. Alchemist - just because an impeller swap makes more boost, does NOT mean it is better. There are many ways an impeller can be altered to make more boost for a given blower speed, but they are generally less efficient. In general, the "flatter" the blades are, the more boost they will make in the low/mid range. The more "sweep" the blades have, the more efficient they will be and make more boost at higher impeller rpm. If you switch a d1sc impeller out for one that makes more boost, you probably aren't going to gain much because of the drop in efficiency. You'd be MUCH better off just spinning the more efficient impeller faster to make the desired boost.
2. The procharger impellers are already billet from 7075-T6 aluminum, and have state of the art design and testing done to optimize the impeller efficiency. The way to make more boost and retain the same efficiency is to make either the inducer or exducer larger. In other words, a different blower.
3. Tightening the clearances will improve efficiency. Factory vortech or procharger blower are going to have a set clearance. If you want your blower to live unserviced for years and take severe beatings, leave the clearance alone.
I am not here trying to argue, nor am I blindly supporting Jon Bond Performance, but the JB impeller has a 10mm larger exducer diameter. That explains how it achieves more boost. It also has deeper inducer cutouts and the overall height of the impeller has been raised "slightly". All of this still fits in a D1SC case without modifications to the case. So it has to be tightening clearances with the case, thus raising efficiency in the process.
The JB impeller is made from similar materials and undergoes similar testing to the stock impeller, so we can assume with some margin of safety that they are equally resilient and equally durable. We even have photographic evidence of what one looks like when it kisses the case due to bearing failure.
The aftermarket impeller tightening clearances is the only thing to worry about in my mind, but even that has the additional benefits of raising efficiency. If it is that big of a concern, I am sure you could have the inside of the blower milled to restore factory clearances with the slightly larger impeller. Steve Morris still does the internal CNC Pro-Volute machining to F-series blowers. Any internal machining is going to be removing metal, so the clearances can only expand.
It is going to cost $1,500 to have a D1SC rebuilt anyways, even with just a new stock impeller. It costs $1,500 to have it rebuilt by JB with the 1475cfm impeller. In the performance world we do a lot of things that reduce clearances in the pursuit of power and/or efficiency. It literally doesn't make sense to be afraid of trying an aftermarket impeller because it might be reducing clearances with the case. We have seen what happens with the impeller in question when it touches the case. We tighten quench and PTV clearances all the time without a second thought, so why should this be any different?
You wouldn't want to machine the volute larger after the larger wheel. The tip clearance is much of what is making the wheel work better. It's all about reducing leakage and more efficiently 'throwing' the air molecules down into the volute.
On the volute side, it's all about collecting the air. You should be able to pickup some flow by porting the diverging section.
IF I ever get enough time I'll model up my P1 and run it through some CFD and post for all. IMO- the blower doesn't seem that well thought out, and much like a highschool science fair project. I wasn't impressed when I took it apart for a rebuild.
I see the larger impeller/tighter clearances as a benefit, and it is a a large part of why I am so eager to try this out. For a kill mode ProCharger build, an F-series blower with the JB impeller and the Steve Morris internal CNC Pro Volute milling, as well as their external Pro Volute bell, would be the ultimate blower in my mind, in terms of both power and efficiency.
the JB impeller has a 10mm larger exducer diameter. That explains how it achieves more boost. It also has deeper inducer cutouts and the overall height of the impeller has been raised "slightly". All of this still fits in a D1SC case without modifications to the case. So it has to be tightening clearances with the case, thus raising efficiency in the process.
Taller blades will almost always = more boost.
Closer tolerances/clearances will almost always raise efficiency.
That is compressor basics.
BUTTTTTTT, those tolerances are there for a reason....
1) Bearing play
2) Temperature variation from winter climates to scorching hot track days
3) Material give when spinning 65k+ rpm in a centrifugal motion.
So sure you can spend a few pennies and maybe sneak out a couple HP.
(which won't be much) But how much longevity are you willing to sacrifice?
When you are talking something that spins at the rpm's blowers and turbos do... I am not really inclined to change things like tolerances. Just my .02
NOTE: Most people could find way more power by optimizing their intercoolers and tubing. If I had a dollar for every person that had a 5-10psi pressure drop across their intercooler they bought for $125 off ebay, I would be rich. (Yes, some of them work good, but many do NOT).... people really need to put a boost gauges BEFORE and after their intercoolers, when making something custom to accurately measure pressure drop. Its worth the $8 for a coupler to use as a test port, before spending good money on sneaking a few extra HP out of a tightened tolerance compressor.
If the blower is more efficient with tighter tolerances, it should be capable of producing the same power as an unmolested blower at a lower rpm. If you do not have to push it as hard, then the chances of those tighter tolerances becoming an issue lessen substantially. A dual nozzle meth system spraying both before and after the blower should help quite a bit with keeping heat expansion to a minimum. And the SKF/GMN ceramic bearings that Jon Bond uses in their rebuilds should be up to the task.
If it is worth it to increase the efficiency of the intercooler and intake tubing, then why wouldn't it be equally worth it to increase the efficiency of the blower itself?
Remember, the impeller in the picture spun to 90k and bearing failure caused the contact with the case, not blade warp. I do not plan to spin my blower past ProCharger's recommended maximum, so increasing efficiency in the normal operating range is something that interests me.
If the blower is more efficient with tighter tolerances, it should be capable of producing the same power as an unmolested blower at a lower rpm. If you do not have to push it as hard, then the chances of those tighter tolerances becoming an issue lessen substantially. A dual nozzle meth system spraying both before and after the blower should help quite a bit with keeping heat expansion to a minimum. And the SKF/GMN ceramic bearings that Jon Bond uses in their rebuilds should be up to the task.
If it is worth it to increase the efficiency of the intercooler and intake tubing, then why wouldn't it be equally worth it to increase the efficiency of the blower itself?
Remember, the impeller in the picture spun to 90k and bearing failure caused the contact with the case, not blade warp. I do not plan to spin my blower past ProCharger's recommended maximum, so increasing efficiency in the normal operating range is something that interests me.
Well, I look at it from the point of...
I want the best gain possible for each dollar I spend.
And would like to INCREASE my cars durability aspect.
So lets look at the two examples....
Modifying impeller tolerances on a small blower:
Well, all that work your looking for "efficiency" might yield you...
Total gain of maybe....1-20hp.
Yet drastically effect the longevity of the unit, and rpm capabilites.
Not to mention costs involved
(And then don't even get me started on the how the boost curve is effected by those curved blades, without the exducer being properly sized)
Or, a person could actually test/optimize their intercooler system:
I have seen people pick up 50-250+ Wheel HP, with this alone.
Takes stress away from the engine/blower/turbo
Costs usually are not that high
Not trying to be a hater, just speaking on what I have seen for the last 20 years I have been around blower/turbo combos. It is what it is...spend the money where its best spent. And focus on whats the best Dollar per HP gain. And 99% of the time, that's in the intercooler system on Turbo/Blower cars. Then after the intercooler is the #2 place to find efficiency... the CAMSHAFT!!!! There are so many **** poor "blower cams" out there is freaking crazy. Its nice that people are starting to do actual back to back testing in test cells and proving that some "Stage 1 and Stage 2" cams yield NO power or TQ difference, other than one has a crappy idle. LOL. But now I am getting way way off track, but I think you get my point. The blower "impeller" should be the last thing on a persons mind.... when there are so many other MAJOR gains/improvements that can be made elsewhere.
NOTE: "ceramic bearings" when used in a blower, I have not seen do any measurable value..other then sounding cool to say it has them LOL (due to the loads involved..takes away a little drive power, but does not extend rpm range or load handling)...
09-07-2016, 10:46 PM
