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Discussion Starter · #1 ·
I've got a 240sx supercharged V8 swapped with an M90 off a 3800. I'm making about 6 PSI after pulleying down to 2.8. That's just how these motors take boost apparently but I've noticed that I can't really hear the supercharger at all. I've seen Mustang guys putting "sound tubes" so they can hear their superchargers.. is it possible to do the same thing here? From the looks of it, it's literally just a rubber hose before the MAF, plugged through the firewall and into the cabin so you can hear the blower louder.
 

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It's usually based on how open the intake is, along with how much the exhaust is not overwhelming the noises. Not sure how the different engine setup may also impact this.

Have you filmed a drive-by shot, to see if the sound is happening outside differently than inside the car? I haven't started a RWD project, yet, to know what the layout does to change it. You can see how 2003-4 Cobras were setup, since they screamed pretty good in most forms.
 

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Discussion Starter · #3 ·
I'm using the stock 3800 throttle body, and there's probably 10 inches of 3" pipe as the intake. The exhaust is way too loud but I didn't think that would drown out the sound of the m90 so much. From outside the car it's not that loud either. Could it just be that I'm not pushing enough boost? Would that sound tube work as just something for me? I just wanna hear the blower work a little more than I do currently
 

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Typically, think of anything in front of the blower rotors as a restriction. It is basically a vacuum, and smaller diameter things like the stock TB, or a long small diameter pipe like that is making it suck thru a straw. The optimal setup would be as short and large of a path to the inlet as possible to get the best from it.

I've seen one or two Camaro swappers modify the inlet to have a large bend to point the TB forward or to the side. You can also try re-shaping the intake layout to be near the wiper tray. Tons if options, but adding a tube somewhere for sound is very goofy sounding while there's actual improvements to be made.
 

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The eaton m90 has no issues making its noise even on a stock size pulley (that is with an aftermarket air cleaner of course) on the 3800. Your also talking about it on a different motor in a different vehicle with different harmonics at play. Sound waves can cancel each other out if they're hitting the right frequencies. 6psi seems on the low side to me for a 2.8" pulley, but your also running it on a v8 which I'm also assuming is better flowing than our engines.

Do you hear the blower if you rev the engine off the throttle body linkage? I personally would not do the sound tube, that is tacky & seems like it would be allowing unfiltered air into your engine
 

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Discussion Starter · #6 ·
The eaton m90 has no issues making its noise even on a stock size pulley (that is with an aftermarket air cleaner of course) on the 3800. Your also talking about it on a different motor in a different vehicle with different harmonics at play. Sound waves can cancel each other out if they're hitting the right frequencies. 6psi seems on the low side to me for a 2.8" pulley, but your also running it on a v8 which I'm also assuming is better flowing than our engines.

Do you hear the blower if you rev the engine off the throttle body linkage? I personally would not do the sound tube, that is tacky & seems like it would be allowing unfiltered air into your engine
Yeah when I rev it off the TB I can hear it. when I'm in the car I can't hear it anymore. I think the insulation is just too effective. I could look into changing throttle bodies and intake diameters.. I could also go with the tacky option for now and just see how it sounds. Worst case it does nothing and I'm out 2 hours. I could put a filter over the hose too.
 

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Pics would help a ton for advice. Packaging in swaps is always an obstacle, especially with a FWD setup in a RWD.

There's almost a guarantee we can come up with a few options/parts that won't break the bank to get you better routing, with improving HP a bit as a side benefit of less restriction. I've spent the past 20yrs doing things on a tight budget with these cars, just slowly accumulating parts and information on how to use them efficiently. I guarantee you'll only make this thing better and better the longer you have it, if you tinker with optimizing little things every now and then... But enjoy it whenever it's up and running.
 

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what is the displacement of the V8? Maybe the M90 isn't the right SC for the application.

 

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Discussion Starter · #10 ·
Pics would help a ton for advice. Packaging in swaps is always an obstacle, especially with a FWD setup in a RWD.

There's almost a guarantee we can come up with a few options/parts that won't break the bank to get you better routing, with improving HP a bit as a side benefit of less restriction. I've spent the past 20yrs doing things on a tight budget with these cars, just slowly accumulating parts and information on how to use them efficiently. I guarantee you'll only make this thing better and better the longer you have it, if you tinker with optimizing little things every now and then... But enjoy it whenever it's up and running.
Vehicle Automotive tire Hood Motor vehicle Car

I absolutely adore this car, just hoping i could squeeze a little more out of it in terms of sound is all. I'm gonna get the blower ported soon to cut down on the intake temps
 

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Before digging into that blower more, I'd actually suggest keeping an eye on Australian eBay for a Holden M90 (3800 L67 "ecotec" Commodores) that has the elbow integrated in the housing. You've done what you needed to get going, so now refining is going to be less of a rush.

Motor vehicle Vehicle Automotive tire Gas Automotive fuel system


Blower porting isn't a huge thing, more of a snake oil "upgrade" many people do because it doesn't take too much digging in to accomplish. There's a minor benefit on Gen 3 M90's to trimming the bolt bosses on the outlet and making the inlet a bit smoother/larger, but it's very minimal effort-to-improvement ratio, to the point that you may not even notice on a dyno or track.

As far as 4.0L being in the M90 range by Eaton, sure, but then again, wouldn't that mean I shouldn't have had to upgrade to their 112ci blower to improve the power potential on my 3800? That thing is spec'd even higher, with 4.xL's being on the lower end of OEM uses (Ford/Jaguar), but it's among the top 3800 HP cars of all time, alongside a Whipple and KB swap.

Lots of options for upgrading if you ever want to do more...


(2003-2004 SVT Cobra M112)


(Early 2000's F-150 Lightning M112)
 

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Discussion Starter · #12 ·
Before digging into that blower more, I'd actually suggest keeping an eye on Australian eBay for a Holden M90 (3800 L67 "ecotec" Commodores) that has the elbow integrated in the housing. You've done what you needed to get going, so now refining is going to be less of a rush.

View attachment 11345

Blower porting isn't a huge thing, more of a snake oil "upgrade" many people do because it doesn't take too much digging in to accomplish. There's a minor benefit on Gen 3 M90's to trimming the bolt bosses on the outlet and making the inlet a bit smoother/larger, but it's very minimal effort-to-improvement ratio, to the point that you may not even notice on a dyno or track.

As far as 4.0L being in the M90 range by Eaton, sure, but then again, wouldn't that mean I shouldn't have had to upgrade to their 112ci blower to improve the power potential on my 3800? That thing is spec'd even higher, with 4.xL's being on the lower end of OEM uses (Ford/Jaguar), but it's among the top 3800 HP cars of all time, alongside a Whipple and KB swap.

Lots of options for upgrading if you ever want to do more...


(2003-2004 SVT Cobra M112)


(Early 2000's F-150 Lightning M112)
I've also been looking at the m112 blowers, they're just way more expensive than the 80 dollar junkyard supercharger I currently have. I've heard the ports aren't so much for performance as they are intake temperature control.
 

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Running E85, an intercooler plate, or meth injection kit is a good solution for that, if you really want to optimize the boost later on.
 

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Thats a real interesting setup you have there. The first thing that strikes me is your filter is between the supercharger & the exhaust manifold both of which are big heat sources. Also being so close to the engine maybe the noise from the engine is drowning out some of the noise from your intake. I would at the very least extend the intake tubing out into that empty space behind the headlight and put some kind of heat shielding between the filter & radiator & maybe even go as far as wrapping the intake tube (i'm just crazy like that lol).

As the others have said there is definitely room for more upgrade & refinement to your project.
 
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