Any point to porting/ polishing the supercharger top?

1FSTBRD

Registered User
Has anyone tried doing this and if you have, would it be worth it to do? I was thinking that shaping it and removing a bit of resistance from that area may help.
 
The top hat, or the super charger outlet? Every ported SC I have seen has the outlet "triangle" opened up, but the inlet is where any real gains come from, as that is where this SC design is constricted. As for the top hat, MP raised tops are popular and well designed to open up the "squeezed" section of the neck, but someone on this site who does a lot of dyno testing has reported seeing NO power improvement, and very little improvement in blower outlet temps. I also have two tops that someone else built to do exactly what I believe you are asking about. I'm gonna use them, will they make any improvement????? But all the cool kids r doing it!!!:D

Adam
 
I'm talking about the top hat (a cane will be next :D ). I have a late model blower where the triangle had been opened up before I had bought it. My SC is in storage right now, so I can't take the supercharger top hat off, so could someone provide a picture of what it looks like on the inside? I'm wondering if gains wouldn't come moreso from a rounded angle, rather than a bigger size (like in the case of the raised top showing little to no improvement).

Also, if anyone has any theories or ideas on restrictions on the intercooler piping (other than the intercooler, itself), that would be awesome. Would there be any point to porting and polishing the whole intercooler setup? I was thinking that I may do that, as well, but I'm not sure if there would be any drill extensions that would be long enough to get in there--maybe a longer bendable one?
 
There's not much you can do to increase flow through the stock supercharger top. There are raised profile models available. Check with Magnum Powers. Theirs is the nicest. There are some hand-modified ones out there that are cheaper, but don't look as nice, and the fit may vary.
 
The one thing the stock IC can benefit from is a good cleaning, off the car, rinsed a couple times w/cheap gasoline until it flows out clear. After so many years, they can suffer from being oil coated inside with a reduction in heat shedding ability.

It's also a good time to straighten fins, confirm the air flow baffles are intact and add a small fan.

As far as the tubes, there is an entire science behind extrude flow honing and certain coatings that help throw heat out and block engine bay heat in, but those aren't cheap, and it can be a hard ROI, where that money could go into a FMIC, etc.
 
The one thing the stock IC can benefit from is a good cleaning, off the car, rinsed a couple times w/cheap gasoline until it flows out clear. After so many years, they can suffer from being oil coated inside with a reduction in heat shedding ability.

It's also a good time to straighten fins, confirm the air flow baffles are intact and add a small fan.

As far as the tubes, there is an entire science behind extrude flow honing and certain coatings that help throw heat out and block engine bay heat in, but those aren't cheap, and it can be a hard ROI, where that money could go into a FMIC, etc.

Good points. Would carb cleaner work through the intercooler? I'd got a Ken Wagner DIC last year and had installed it and it had worked well, but am wondering for maintenance reasons.
 
I decided to port and polish a spare sc top. I'll have pictures up either today or tomorrow. There is some pretty bad welds and casting issues for the air to negotiate. I was wondering if a bigger size of sc top (ie: Magnum Powers) or a higher/ welded top may increase the volume of flow, but reduce velocity/ pressure. Is that a fair assessment of why some guys don't see any benefits to an MP raised top, without running a much bigger blower?

I took the car out on the highway, and after all my mods beforehand and exhaust, the car was at about 10.25-10.5 psi of boost (just barely cracking the 10 psi mark). It's a mostly stock '89 engine, with a few bolt ons. After the ported/ polished stock sc top, the car was at about 9.25-9.5 psi of boost. The needle definetely doesn't scrape the 10 psi mark. Low end feels about the same, possibly lost a small bit of torque, midrange feels smoother out of the torque curve (may have moved the torque peak up a bit?) and 3000-4000 and 40-60 mph feels stronger, whereas in stock form, it struggled more in the upper rpm's.
 
Here's the pics:

Top hat exit stock--not too bad, but the inner tube part doesn't match the outer collar connector part, a step which would cause some turbulence going into the connection at the top IC tube:

sctophatexitstock.JPG

Ported and polished--no trace of any inner tube with the collar connector transition or step:

sctophatexit.JPG

The inside of the stock top hat--the two round casting bumps in the middle can't be good for flow, nor can that nasty assed weld. The fins are pretty good in stock form:

sctophatstock2.JPG

Ported and polished:

insideofsuperchargertophat.JPG
 
The inside mouth of the exit to the intercooler in stock form (the roughness of the welds show here a little more on this angle).

sctophatstock.JPG

Ported and polished version--I speculate that if one were to do a real quick, crude version of this (all in all, this was about 10 1/2 hours for a small psi drop), you could get away with a few hours' work in just grinding down the two round casting flaws, as well as the welds, and this throat area:

portedandpolishedsctophat.JPG
 
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