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Yes while the rotational mass is about 4 pounds lighter in the final revision, torque is not sacrificed, as with a flywheel. These masses assist with reclaim. These were originally designed to RECLAIM the balance shaft system 5hp loss.
Those are some nice parts you have made, lots of time and skill there. I'd be lucky to have them on my engine.
I'm not sure I buy your explanation above though. Maybe you could rewrite it a bit more clearly?
Hi Mike: yes labors of love for sure. But as a well known enthusiast once said, Porsche Passion. Porsche saw fit to put those on the cam shaft for a reason, there are certainly benefits to adding mass and certainly drawbacks. Its an act of tradeoff, it looks as though theres a gear train, please correct me on this, if wrong. if so, then mass there is registered throughout the entire mechanism via rigid means. the generated torque is transferred very possibly to the crank. At the sacrifice of the gear train and noise.
The belted cam motors are lossy. So the masses are not tightly coupled. It worsens with hours of usage. The less additional mass on the belt systems the less the load. This reduces wear and stretch making timing more accurate on the cam and balance shaft gears. Also these parts have slightly tighter tooth geometry than the factory steel parts, and there's an offering for TFE impreg anodize, for extremely smooth slick quiet running with very low belt friction.
These gears and pulleys are designed to reclaim hp and to impact torque as little as possible, through mass, balance, load, precision, harmonics and accuracy. Its great to see new conversations and interest.
Hi Mike: yes labors of love for sure. But as a well known enthusiast once said, Porsche Passion. Porsche saw fit to put those on the cam shaft for a reason, there are certainly benefits to adding mass and certainly drawbacks. Its an act of tradeoff, it looks as though theres a gear train, please correct me on this, if wrong. if so, then mass there is registered throughout the entire mechanism via rigid means. the generated torque is transferred very possibly to the crank. At the sacrifice of the gear train and noise.
The belted cam motors are lossy. So the masses are not tightly coupled. It worsens with hours of usage. The less additional mass on the belt systems the less the load. This reduces wear and stretch making timing more accurate on the cam and balance shaft gears. Also these parts have slightly tighter tooth geometry than the factory steel parts, and there's an offering for TFE impreg anodize, for extremely smooth slick quiet running with very low belt friction.
These gears and pulleys are designed to reclaim hp and to impact torque as little as possible, through mass, balance, load, precision, harmonics and accuracy. Its great to see new conversations and interest.
Jeff
AKA/FT-Factorytuned
Hi Jeff, thanks, that makes sense.
EDIT: Yep 587 motor has gear train. Flywheels added to combat valve train harmonics at 7200 rpm.
Porsche engineers have always had a very good understanding of resonance and harmonics. Cosworth had a more elegant solution though...
I was talking to a fellow im doing custom exhaust flange work for, and had ask about alternators, but more to point, regarding the Bausch unit specifically, with no interest in aftermarket units made to work. Is there any interest in a true fan for these factory Bausch alternators??
It'd provide much needed and more progressive cooling and draw, to assist with sag due to heat, and also bring some real balance, a bespoke feel and aesthetic. All aluminum and light weight, of course matching existing designs and bolt-on in place of the Bausch steel eccentric paddle, which does very little but minimum, and next to nothing at low revs and idle. I can add a photo of the prototype model. Comments and interest?
Why:
The cooler the alternator runs, less noise and VA sag.(more consistent output)
With all Aluminum design pulley and fan assist to draw heat from the stator core and bearings. (So now all aluminum where there once was steel only)
Cooler diode package (heat kills diode/transistor performance and life)
Less noise, less sag, less damage to ECU and more power to pump.
If youre looking for a replacement for a worn out dual mass no. I don't make dual mass aluminum or steel dampers/ harmonic balancers. However my dalance shaft drive gear is compounded for a similar reason.
i am designing for a fellow who just ordered, a BSDG delete hub, that will be compound loaded for that purpose.
jeff
aka-ft/factorytuned
Originally Posted by Ish_944
I couldn't find this out from your website: do you also have a replacement for the harmonic balancer?
Sort of in context. In putting together our latest race motor we decided to remove the balance shafts. We're running a custom damper with integrated drive pulley to minimise 'stuff' hanging off the nose of the crank. However when we were deciding to remove the balance shafts we thought about it for a while. We had a catastrophic failure on a previous motor and put that down to crank whip and bad harmonics. So we were cautious in deciding to go with or without B-shafts. Eventually it was decided that since the B-shafts were designed around a motor that is 30 years old and mostly built to assist in quelling ugly large 4 cylinder harmonics in the mid range (so I'm told) AND everything inside our motor was going to be different, then the B-shafts may not be relevant for us. By going with the custom ATI damper we are hoping that this works for the motor that it has been designed around. Long question, long...were we right in assuming that as all the moving parts are different (mostly lighter) that the original B-shafts wouldn't have such a bearing on a custom motor?
If youre looking for a replacement for a worn out dual mass no. I don't make dual mass aluminum or steel dampers/ harmonic balancers. However my dalance shaft drive gear is compounded for a similar reason.
i am designing for a fellow who just ordered, a BSDG delete hub, that will be compound loaded for that purpose.
jeff
aka-ft/factorytuned
Yep, I was thinking about the harmonic balancer like on the S2.
I reckon a well-priced harmonic balancer would have a sizeable market since it's NLA and RS Barn's rather expensive.
Edit:
Afaik, the harmonic balancer is not dual-mass, that would be the flywheel. Instead, it "only" has a rubber piece holding together two metal pulleys.
Yes we could make a dual mass damper/harmonic balancer and likely reduce the weigh fair amount with dissimilar alloys.
Dual mass in this regard: a primary and secondary mass - discretely coupled via elastomer or viscous compound.
With regard to Patrick's "inquiry", an engine lab is required on the scope of factory or thoroughbred large scale engine builder to understand exactly what you're dealing with in regard to the resonant frequency your old motor config was working at and that may or may not have caused it to fail. But if you have unlimited $$$ resources, its likely you could have any motor lab bespoke engine manufacturer research this for you, and a pair of balance shafts made that work in the correct frequency and phase angle to correct and cancel the harmonic anomalies, and subsequently silence those frequencies and provide the trade off data. The same is true for your new motor. Or you could just buy a bespoke motor from said manufactory like the Mountain Racing BTCC or Katech. There are a ton out there, L-4 2/2.5l that would drop right in and spin 10/12krpm steady state.
On topic, precisionasr could make an G6 balanced bimetal damper with the appropriate compounding elastomer to control high frequency ring ama 6db or so in a range. However the torsional dampener part is steel alloy as crank twist is an inertial property mass/energy/time, as we know, on order of control. Trade off, more stored mass energy.
For me, making those to sell, well Id have to have obligated individuals on board in a rather large number. as it'd be hardly worth the design time although since we own the shop and machines, CADCAM, FEA, all in house, they could be a bit less costly on order of 30/35% and weight savings of about 30% on primary mass, best estimate.
whos in?
Last edited by FT_Factorytuned; 09-04-2016 at 02:41 PM.
Interesting response Jeff. Don't know a whole lot about those high end shops that you link to. Assuming you had very deep pockets, do you ship them a block and they do the rest or do they start from scratch (billet)? Assuming anything is po$$ible. What I've 'invested' in these 3 motors I probably could have got a seat at their table but hindsight is a wonderful equalizer.
While we've lightened pretty much everything on this motor we haven't gone down say the knife edged crank path. Feel like we learned that lesson on the failed motor. We looked into custom cranks but that asked more questions than it answered without a lot more time and money invested. My guess is that the damper covers a wider range than the stock B-Shafts did even though they don't serve exactly the same purpose.
In as much as we've done everything ($hort of visiting billetworld) to increase the structural properties, the spacing of the headstuds proves to be the perennial Achilles heel for these big bore motors. Designing all the components in the quest to minimise ugly harmonics would be interesting to say the least.
Nice to see someone giving props to Dave @ Mountune. Legend.
Couldn't figure out why someone from South Carolina is referencing "big Dave" but then I remembered the connection to the other Dave (Vizard), who is now based in North Carolina.
Henry, good for you... Nice 968, they all need some TLC at this point, but as I said, once well sorted they give so much back.. Thank you again, and let me know. I'll be glad to do whatever you need.
The following is a product review of the components I purchased from 4451 ASR and installed in my '89 944 NA back in Oct 2017.
For the record I purchased and installed the Adjustable Cam Gear, the Balance Shaft Gear Set and Drive Gear, and the Underdrive Components.
I was interested mainly in the Adjustable Cam Gear to advance the timing in order to lower the power band for better response on the street, and not for racing.
And the results of advancing the timing by 4* were worth the effort, but after 20,000 miles since the installation I had to remove the gears due to excessive wear and reinstall the steel gears.
The light alloys used in the manufacture of the gears did not hold up to even the replacement of the timing belt interval of 30,000 miles.
For example, below is one of the Balance Shaft Gears:
You can see the wear along the belt path with the concave wear across the top of the tooth. This caused a considerable amount of fine dust within the timing gear cover that required cleaning before reinstalling the steel gears.
Even the Balance Shaft Drive Gear experienced the signs of wear on the top of the teeth as seen below:
The Adjustable Cam Gear also suffered from the excessive wear which resulted in the removal of all components and the replacement of the steel gears:
The lesson I learned afterwards was to install an offset camshaft key to provide the low range torque I was seeking. Specifically from 928 Motorsports, here is the link https://928motorsports.com/parts/off...aft_keyset.php
This post is not a disclaimer of the products mentioned above as they may be beneficial to the racing community, but for the daily driver it is impractical and you could get the same results from advancing the cam gear by installing the offset key and save a ton of money.
08-27-2016, 07:59 AM
