After believing my 2002 R53 to have the dreaded blown supercharger, I set about sourcing a new s/c. I found a s/c body on the forums, which had been ported and noise reduction ports closed. Thankfully there was nothing wrong with my supercharger in the end (blown alternator bearings *sigh*) and so I figured since it was apart, I may as well put my s/c snout onto the ported s/c. I didn't think too much of it, until I had gotten the car back together.

I can't claim to have even any butt dyno experience of the ported s/c because while the car was apart I also added a 15% reduction pulley, one stage colder plugs, and an invidia exhaust. However, I must say I was surprised by not only the power add, but the noise of the supercharger. It's much louder than before, and to my knowledge, the 15% reduction should only make the noise begin sooner, rather than have it be overall louder.

I have since done quite a bit research as to whether or not porting the supercharger and closing the noise reduction ports actually adds power. Some old threads said it could add as much as 7hp, others said there was no empirical evidence to suggest it adds any power, only noise. However, I couldn't find a clear cut answer one way or another. I found a source from Eaton describing noise reduction ports as such:

"When you stomp on the gas, the boost shoots up and the air flow goes supersonic. The air then slams back into the output plate and through the leakage slots, which reduces the hammering of the air into the housing causing less noise. The OEM can not have such loud NVH, that’s why we put them in the housing. The 2 small ports are not there to feed air, only to reduce noise."

So; does porting the s/c and closing noise reduction ports increase hp? If it does this by increasing boost / airflow, should I be running even colder plugs than the standard one stage colder for 15% reduction pulley? And finally, might I need to increase the injectors size to keep the car from running lean given the increased air it might be getting?

*if this should be moved to another section of the forum please lmk*

 

Some owners of supercharged cars -- like the Dodge Hellcat -- claim a ported/polished supercharger added HP. Don't recall any numbers. Some did this to the supercharger on a stock engine others did it on a supercharger mounted on a modified engine.

If your car is running good not manifesting any problems and making good power you might be better off leaving well enough alone.

If you want to try the ported/polished supercharger thing with the engine in good tune for its present condition make some dyno pulls and establish a baseline regarding HP/torque and their curves.

Then port/polish the supercharger. If the engine is in proper tune before this if the fueling system is adequate if the injector aren't bumping up to too high a duty cycle it is possible the engine will need nothing. I mean if this port/polish even delivers any extra HP/torque and I'm not saying it won't or it will I have to believe it won't be mega amounts.

But of course you can and should consult --- before you do anything -- with a shop that will do the work and find out what its experience is regarding the amount of HP/torque gain and what mods/enhancements the engine/fuel/cooling system need so no harm is done.

 

Thanks for the info @RockC ! Agreed that I likely would have been better leaving well enough alone with the working s/c body I had ... but since I had the supercharger off and apart to inspect the bearings within, and had already purchased a ported supercharger body from another NAM member, I decided to reassemble my s/c snout onto the ported s/c body.

Since I'm now unable to do a direct comparison between regular s/c and ported s/c (Without a lot of work that is) I was curious if anyone had tried and true numbers on
A) What the hp increase might be and
B) if it might need any supporting mods such as larger injectors or colder plugs

 

By chance was this the sc I'd ported and sold a a year or so ago ??
I ported it by opening ot up by the rotors opening and I opened up that V slot on the hat as well as sealed the side silencer slots on the hat also...but I did install a new performance aluminum coupler on the snout of it along with seals.

 

Sure is! Thanks again, big fan so far. I ended up purchasing just the sc body from you, no snout. I used the snout from my sc and new plastic coupler - would have been cool to do aluminum, I didn't know that was a thing. I saw your ported horns on the marketplace a few days ago...would have picked them up if I wasn't enjoying the car being in once piece lol.

Seems to make more power and scream way more than your average 15% pulley, but have no way of knowing since I did both mods at once. Any thoughts on how significant the difference is of ported and closed ports vs not? Think I'd need anything to accompany the potential boost increase above the 15% pulley?

 

I can't say for certain, I never tested it befor and after with exactly same seteup ect to compare or anything..
but, , hoe much psi are you making with it on the 15% pulley and was it a pre or post facelift sc , I forgot ?

 

I believe both are pre-face lift, this is the comparison photo of the two. Don't have psi numbers on hand, is there a way to measure those outside of installing a boost gauge?

 

Get the OBD Fusion app and a Bluetooth OBD II dongle. It will measure boost and a ton of other engine performance specifics and broadcast the info to your phone.

 

Thanks! I have the Carly OBII and app that I use for my E92, I think it should work for the R53, I'll try it out and grab some some boost numbers and AFR if the computer reads that. I suspect it may need a tune and/or bigger injectors as it seems to have some hesitation around 3000rpm and can kind of cut out under WOT

 

Digging this thread up as I saw some 380cc injectors for sale on the marketplace ... with a ported s/c, M7 CAI, 15% s/c reduction, one step colder plugs, invidia exhaust and no tune, would 380cc injectors be recommended? Is $250 for a set from a low miles JCW a good deal?

Thanks

 

absolutely... the stock fuel injectors barely flow enough for an 11% pulley , intake and exhaust...its big reason by the jcw injectors started being used... honestly, 380cc even then is getting close to max duty cycles with your mods.. imo to be 100% safe 440cc are the way to go.
though I too am running 380cc in one of my mini with ported everything , 19% pulley and full exhaust at 19psi max , it is running atad lean at wot. Buuuut i dont have any detonation or pinging yet buuuuuut with summer coming , I fear I might need to step up to 440cc and have adriancl tune it instead of running the gp tune and 380cc..
imo I wouldn't pay 250 for jcw injectors. Your just paying for oem markup.. imo run the ebay 60$ 380cc clone injectors. I ran them in 3x of my personal cars with 0 issues and BOTH my buddies ran them too until they had to step up to larger injectors also but they too had no issues.
don't get me wrong oem are oem and ebay ones are , well , Chinese BUT hey , for 60$ imo you can't complain.

 

Nice, thanks for the info. I was hoping someone would recommend I go even bigger! (because bigger is better right?) I haven't measured it but can only assume the car is running a bit lean now. I read a thread once about how the injectors can scale themselves up pretty well but I haven't found it again with some recent digging. I also tend to assume it's not quite doing it right as I don't think the computer is keeping up well with the mods now...it *could* be belt slip, but it feels like power sort of cuts out intermittently at wot, especially in 2nd and 3rd. I think getting 440cc and a tune would be the next logical step.

Do those Chinese ones you mentioned throw any codes? I've heard it's hit or miss, and that there are some volvo options as well, I think maybe I even saw you selling a set once? Thanks