porting supercharger

bigal61

Registered User
rebuilding motor due to cracked piston. I plan on boring 20 over and adding 1.8 roller rockers other than that build will be stock would porting SC be worth the time?
 
Use the search engine on this site to see pictures, and what to do, or not to do. Porting a supercharger in the wrong places can affect performance in a major way. What superchargers do you guys have, the 89-93 or 94/95?
 
I am having mine ported by james right now in the thread for davec73 we are trying an experimental port in a pear shape and I am going to post results once I get it installed. The heads are the real bottle neck on this car if you port the supercharger you should really think about porting the heads and opening up the exhaust to handle the extra boost. I am hoping to get around 17 psi out of mine with the mp inlet port work and I am looking for a kw double inner cooler with a fan.
 
I am having mine ported by james right now in the thread for davec73 we are trying an experimental port in a pear shape and I am going to post results once I get it installed. The heads are the real bottle neck on this car if you port the supercharger you should really think about porting the heads and opening up the exhaust to handle the extra boost. I am hoping to get around 17 psi out of mine with the mp inlet port work and I am looking for a kw double inner cooler with a fan.

How much OD are you going to run to get that? I'm getting 15psi with 15% OD, MP Inlet and full 85mm Induction.
 
Do not by any means overdrive the blower without upgrading your fuel system. the exhaust doesnt cause blown head gaskets, a lean condition will. before any major mods make sure you have a fuel system up to it, and uncork the exhaust a little bit, the heads arent a nesscessity to do right away for mild mods but to see the full potential of the mods you do free flowing heads and a free flowing intake/exhaust will show through. you can only do so much with a 94/95 blower.

Port wise, what I did was very mild, disassembled blower, taped up needle bearings, i ground down the bosses for the screws to make it round instead of arrow shaped (on the outlet), i didnt widen the V, if you do it wrong it could disturb rotor timing. And, the way I see it, why play with the devil for minimum gain. On the inlet, on the inside of the case there is a small lip. i blended that lip and open up the square port a little bit. if you look into the case out the inlet it will have kind of a smily face to it. Air flows like water, always keep that in mind when porting. Do a search, and find pictures, Do your research before porting anything.

Good luck
 
It will mostly be the porting we did the pear shape port on the outlet and the inlet will be ported for max flow as well. I am running a 10% od pulley on a 95 and I dont know how that math will work out but demmit was pulling 19 psi out of a similar setup so I am hoping for 17. My intake is ported and I am going to add it to the stock heads I have on the car now but I am in the process of rebuilding a 95 motor with ported polished heads intake with this m90 cam and roller rockers. I will post the results when I get it on the car.
 
Here are a couple examples The first is the outlet port on my 95 the secont is the straight rectangular port on my gtp dont be afraid to widen the triangle just measur it and make it symetrical
pearport.jpg


aportedbloweroutlet.jpg
 
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Errr...why a pear shape? I actually saw the pic and wondered if it was the camera or somethin. Then I went back and now see this thread. I do a lot of stuff myself. I MEAN A LOT of stuff. I would leave the SC porting up to a pro. For two reasons. The rotor timing as mentioned is not the correct term I don't think, but the way the gasses are released from the rotors, and they can leak off causing lower boost. And, I do not have the equipment to do it with the edges I want and a mill to do it correctly.

SWS
 
It will mostly be the porting we did the pear shape port on the outlet and the inlet will be ported for max flow as well. I am running a 10% od pulley on a 95 and I dont know how that math will work out but demmit was pulling 19 psi out of a similar setup so I am hoping for 17. My intake is ported and I am going to add it to the stock heads I have on the car now but I am in the process of rebuilding a 95 motor with ported polished heads intake with this m90 cam and roller rockers. I will post the results when I get it on the car.

How much boost a blower makes at a given drive ratio is going to be determined by many things. More boost does not always result in more power. For example a motor with stock heads and cam will have higher boost, but make less power than the same motor and blower will make with ported heads and cam and less boost.

When it comes to blower porting, the inlet side of the blower is much more important than the outlet side. Bigger air filter, intake pipe, mass air meter, throttle body and inlet plenum will make the blower more efficent and produce more boost at the same blower speed, and that is where the power comes from.

Jacking up the boost by spinning the blower faster just consumes more power off the crankshaft to turn the blower and also ends up producing more heat coming out of the blower. Hot air expands and make boost number even higher, but pumping hot air into the motor kills power because it doesn't contain as much oxygen. It's all about getting the most oxygen in the cylinders, because the more oxygen you have, the more fuel you can burn. Burning more fuel is how you make more power. This is where the bigger intercooler, ported heads and bigger cam really helps.

Changes on the exhaust side of an SC motor don't show nearly as much gains as changes to the intake side of the motor.

David

PS: I don't think the pear shaped outlet is going to do anything to improve blower performance, and may actually hurt it.
 
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How much boost a blower makes at a given drive ratio is going to be determined by many things. More boost does not always result in more power. For example a motor with stock heads and cam will have higher boost, but make less power than the same motor and blower will make with ported heads and cam and less boost.

When it comes to blower porting, the inlet side of the blower is much more important than the outlet side. Bigger air filter, intake pipe, mass air meter, throttle body and inlet plenum will make the blower more efficent and produce more boost at the same blower speed, and that is where the power comes from.

Jacking up the boost by spinning the blower faster just consumes more power off the crankshaft to turn the blower and also ends up producing more heat coming out of the blower. Hot air expands and make boost number even higher, but pumping hot air into the motor kills power because it doesn't contain as much oxygen. It's all about getting the most oxygen in the cylinders, because the more oxygen you have, the more fuel you can burn. Burning more fuel is how you make more power. This is where the bigger intercooler, ported heads and bigger cam really helps.

Changes on the exhaust side of an SC motor don't show nearly as much gains as changes to the intake side of the motor.

David

PS: I don't think the pear shaped outlet is going to do anything to improve blower performance, and may actually hurt it.

I 100% agree with everything you said but I am just trying something new dave. My inlet is going to have a big smile and I am going 85mm filter maf and into the mp inlet with bigger injectors ported heads and the lot I will post detailed results.
 
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