Did some Supercharger outlet porting today
04-25-2005, 10:44 AM
#21
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Renewing a topic that wandered a bit......I know Foghorn'* pics don't work any more, but It'* time to add a bit to it. A word of warning, this modification is NOT for the faint of heart, and you can screw up your Supercharger very easily if you aren't VERY careful.
Yesterday, while extracting my needle bearings, I noticed alot of casting flaws around my outlet port. Taking Foghorn'* lead, I set out to clean it up to improve efficiency, airflow, and decrease outlet temps (sharp edges in the airflow path show up hot in thermal analysis). Not that I did NOT modify the actual size of the outlet port. This is very important.
Before:
Note the restriction in the above pic. This is the underside, nosedrive end.
Another angle of the same flaw. The inside edges near the rotors (in the compressor chamber) don't have this problem, but the air still must turn 90° to exit the outlet port.
__________________________________________________ __________________
In progress:
Removing casting flaws on the inside edge of the outlet. Notice how it actually restricted the opening. They didn't only extend DOWN, but also into the opening. It'* easy to see here while it'* being removed.
Working my way from left to right, getting close to the worst part on the right side of the pic.
Still working on the outlet restrictions, the worst part is very apparent here at the bottom of the pic. White rag under the SC to show the flaw.
Just about done with the inside edges, ready to tackle the bad stuff.
Starting work on the worst of it. ALOT of material was removed here. This was obviously not intended in the design, as the contour of the outlet port was quite well defined, despite the protrusion of the flaw.
Nearing completion. This is after chamfering the outlet, but before fine sanding.
Another angle of the same stage of finishing. Keep in mind that I'm working on the inside and outside simultaneously. The inside is VERY delicate and restricted for working space. The rotors spin at insane speeds, so you don't want to induce a single burr or high spot.
Inside view of the outlet port before finishing.
__________________________________________________ _________________
After:
Ignore the funny stains on the inside of the blower. Those are solvent marks from the ultrasonic cleaner, and wipe right off with Acetone.
__________________________________________________ ________________
Another warning........this is delicate work, and easy to screw up. I'm expecting slightly increased efficiency (flow), and slighltly lower outlet temps. If this buys me a couple horsepower, it was worth the 3 hours I spent on it, as I already had it apart anyway. Much of this is impossible to characterize given the resources I have available, but it'* certain to be at least a small improvement.
Yesterday, while extracting my needle bearings, I noticed alot of casting flaws around my outlet port. Taking Foghorn'* lead, I set out to clean it up to improve efficiency, airflow, and decrease outlet temps (sharp edges in the airflow path show up hot in thermal analysis). Not that I did NOT modify the actual size of the outlet port. This is very important.
Before:
Note the restriction in the above pic. This is the underside, nosedrive end.
Another angle of the same flaw. The inside edges near the rotors (in the compressor chamber) don't have this problem, but the air still must turn 90° to exit the outlet port.
__________________________________________________ __________________
In progress:
Removing casting flaws on the inside edge of the outlet. Notice how it actually restricted the opening. They didn't only extend DOWN, but also into the opening. It'* easy to see here while it'* being removed.
Working my way from left to right, getting close to the worst part on the right side of the pic.
Still working on the outlet restrictions, the worst part is very apparent here at the bottom of the pic. White rag under the SC to show the flaw.
Just about done with the inside edges, ready to tackle the bad stuff.
Starting work on the worst of it. ALOT of material was removed here. This was obviously not intended in the design, as the contour of the outlet port was quite well defined, despite the protrusion of the flaw.
Nearing completion. This is after chamfering the outlet, but before fine sanding.
Another angle of the same stage of finishing. Keep in mind that I'm working on the inside and outside simultaneously. The inside is VERY delicate and restricted for working space. The rotors spin at insane speeds, so you don't want to induce a single burr or high spot.
Inside view of the outlet port before finishing.
__________________________________________________ _________________
After:
Ignore the funny stains on the inside of the blower. Those are solvent marks from the ultrasonic cleaner, and wipe right off with Acetone.
__________________________________________________ ________________
Another warning........this is delicate work, and easy to screw up. I'm expecting slightly increased efficiency (flow), and slighltly lower outlet temps. If this buys me a couple horsepower, it was worth the 3 hours I spent on it, as I already had it apart anyway. Much of this is impossible to characterize given the resources I have available, but it'* certain to be at least a small improvement.
04-25-2005, 05:23 PM
#22
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so this is for lowering the outlet temps? thicker metal at the edges will be less hot, so it will heat the air up less, correct? Looks like a nice grinding job. What about the two holes to the sides of the outlet port, what are those for?
04-25-2005, 05:33 PM
#24
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Yup. Strictly acoustic on the little holes. But they also produce pressure. Maybe 5% of the total boost travels through those.
BTW, the entire job was done with nothing more than a dremel tool, and varying grits of sandpaper, ending with 600.
BTW, the entire job was done with nothing more than a dremel tool, and varying grits of sandpaper, ending with 600.
04-25-2005, 10:46 PM
#25
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Nice work Bill...I knew you'd come around to my way of thinking :P 
.
I fixed my photos in the first post so that people can scope this out once again.
Cheers,
.I fixed my photos in the first post so that people can scope this out once again.
Cheers,
??
07-25-2005, 01:48 AM
#28
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All hand tools. I would have used the Mill with a dovetail bit (or reverse chamfer), but our the CNC machine I needed was shut down for the night. I did all the porting on the LIM by hand as well.
09-16-2005, 10:24 AM
#29
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Originally Posted by Foghorn
Originally Posted by willwren
Looks great Fog, but I have to tell you.....
I've spent some time on the phone with both Magnusson and Eaton in the past regarding a VERY crappy vendor who did this. Both companies made it very clear that their research showed that the standard outlet was more than enough for a supercharger running a smaller pulley, and that little or nothing could be gained by doing this. Offhand, the lead Engineer at Eaton told me to expect less than 2% flow increase BEST case scenario (optimum NEW unit).
I've spent some time on the phone with both Magnusson and Eaton in the past regarding a VERY crappy vendor who did this. Both companies made it very clear that their research showed that the standard outlet was more than enough for a supercharger running a smaller pulley, and that little or nothing could be gained by doing this. Offhand, the lead Engineer at Eaton told me to expect less than 2% flow increase BEST case scenario (optimum NEW unit).
Few people are willing to disclose any actual testing, but ZZP has come close to making information public. If you followed the testing they did on their flow bench, it'* obvious they did quite a bit of work. ZZP deosn't actually say how each of the designs stack up relative to each other, but they did say that the outlet size had little to do with improved flow. They did alude that the trick was in the way the cutbacks are made.
I don't have any way to test what I've done and my only guide has been the testing I've seen, the feedback from some in the GP community and the actual aftermarket products available.
I would guess that from what I've done there will be little improvement in the actual flow. After all, it'* not a positive displacement blower. It injests 90 cubic inches of air per revolution and compresses it, the oulet size may be irrelevant.
On the other hand, there is considerable casting flash in the form of a seam running half way up the casting around the perimeter of the triangular opening. I would think that adds a fair bit of heat and reduces the efficiency of the blower. At best, I would hope to cut down on the heat introduced into the charge and perhaps improve the flow modestly.
Your point is well taken Will, I don't know the exact answer.
Also, I have made some changes because I anticipate installing an intercooler. It will be a custom design, the plans are made, the material is on hand and the program for the CNC mill has been created. The only difficulty is in finding time to put production aside and do the work to machine the housing.
Anyway, at the very least, it was fun to do it.
Cheers,
09-16-2005, 03:54 PM
#30
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A dyno? Really? That'* one of those fancy-schmancy things that tells you stuff about your car, right? 
Ummmm....normal variation from pull to pull on an unchanged car would be more than you'd see from simply porting a SC outlet. The ported outlet supports OTHER mods, but by itself doesn't add any amount that a dyno could characterize.
Ummmm....normal variation from pull to pull on an unchanged car would be more than you'd see from simply porting a SC outlet. The ported outlet supports OTHER mods, but by itself doesn't add any amount that a dyno could characterize.