A ported SC doesn’t increase displacement, it only throws air more efficiently
@svt_cam1143
6 жыл бұрын
Very informative video man. Keep it up!
@feellnfroggy
4 жыл бұрын
Supercharger doesnt get bigger when you port. It simply moves that same air with more ease. The space between the rotors doesnt change.
@JaegerWrenching
4 жыл бұрын
feellnfroggy Define “ease” in terms of flow. This supercharger in stock form with those rotors moves 1.9L of air per rotation. But put them in the case and we now have a flow restriction. So if we remove material and drop restriction you’ve just increased flow per rotation. So technically speaking We’ve increased airflow per rotation. Does that make sense? This is where the thought of mine comes from, but I also explain why I think measuring air volume moved per rotation is dumb, it should be done by the rotors physical displacement or size.
@feellnfroggy
4 жыл бұрын
@@JaegerWrenching it's like using a bellows to stoke a fire. The bellows squishes the same amount of air no matter what. But a larger tip will allow the bellows to collapse easier pushing the same volume of air faster with less resistance. Porting a supercharger is the same. Allows for higher rpm with less stresses. But the volume per rotation is still 1.9 liters. To go from 1.9 to 2.e would require a rotor change
@feellnfroggy
4 жыл бұрын
Not knocking the vid in anyway, you did a great job with it.
@DodgyBrothersEngineering
4 жыл бұрын
@@feellnfroggy it comes from a lack of understanding of the difference between volume and pressure. I just wrote a post explaining it.
@feellnfroggy
4 жыл бұрын
@@DodgyBrothersEngineering I'll have to go back and read it. The difference between volume and pressure is what I was trying to explain.
@jpsantone
6 жыл бұрын
Great Channel! Nice to see terminator stuff.
@erickmacias8840
5 жыл бұрын
How does he not have 1 million subscribers lol
@DodgyBrothersEngineering
4 жыл бұрын
I don't know who you have been talking to, or listen to, but they are so full of crap. The displacement is worked out by the swept volume of the rotors in the blower, and porting the inlet / outlet of the housing is not going to increase the capacity one little bit. All that porting the blower housing is going to do is make the blower less efficient. Yes you heard right, less efficient... Think about how a venturi works in a carburetor. As pressure increases (goes from wide to small through the middle of the carb - like an hour glass), flow decreases proportionally, and as flow increases (comes out of the small area into a larger one) pressure decreases proportionally. There are no free lunches... You need both air flow and pressure for the blower to work. Opening up the ports reduces the amount of sealing area, therefore it decreases pressure. It will increase flow but at a reduced pressure. What do you need to make high boost??? Pressure. By porting the housing you might get slightly better gains of air flow at low boost pressure (you might also lose flow), but as boost increases it will not flow as well at higher boosts levels because you have effectively increased its ability to back flow causing a loss of adabatic efficiency. All of these roots style blowers are not positive displacement pumps. The rely on rotor speed (so the can stack the air in the manifold to produce boost) unlike blowers like Whipple that are positive displacement blowers (they actually make pressure inside the blower, through the sealing on the rotors to one another). Porting a housing that already struggles to make boost is plain loco. Don't you think Eaton spent time and money researching the best design to give them maximum efficiency? What happens when you lose efficiency? It is converted to heat, what do engines hate? HEAT!!! The simplest example I can give is to cast your mind back to when your were a kid, and you were trying to pump up your bike tyres, and the pump wouldn't make any pressure to blow up the tyre. So you would pull the pump apart and try to flatten out the washer so it sealed better against the walls of the pump tube. Porting the housing is like removing the washer altogether, you have just made the perfect environment for it to bypass the outlet nozzle (the point of greatest restriction you are trying to push air through), and provided it with a golden opportunity to flow around where the washer would have been if you didn't remove it. Ever notice how as the bike pump became less efficient (bad sealing) it increased the temperature of the pump tube? (sometimes it got so hot it could burn your hands) This is caused by the friction of the air, trying to bypass the sealing washer. Think of the intercooler sitting right next to the blower outlet to be akin to putting your finger over the end of the bike pump hole.
@DodgyBrothersEngineering
4 жыл бұрын
Looking at the blower at 5:19 I think you could improve the intercooler efficiency... if you filled in the area near the bypass valve with something flexible, or something that doesn't expand with heat (so it doesn't crack the casting), you would reduce the volume of air (you would need to extend the bypass outlet so it didn't get blocked), but if you could imagine a plate over that whole area, it would stop the air coming out of the blower outlet and going into a lower pressure area cavity. Keeping the air velocity up would make more of the air go down to the other end of the intercooler which would allow more of the core to be used. Be worth a try over touching the ports.
@JaegerWrenching
4 жыл бұрын
First off Thank you for sharing your knowledge! I really appreciate you writing everything out and explaining it. I know it takes time and a passion to do it and it’s appreciated. This cleared things up and makes a lot more sense to me now. I will take another look at the bypass Valve and see what can be done there to improve that loss. I do have a couple question. Would porting the blower inlet/elbow, that’s everything leading to the rotors help with moving more air without having negative effects? Second, if that actually helps my next question would then be is that the reason guys make more power when “ported” vs non ported? There are plenty of ported Eaton’s that do make more power than non ported, this typically happens as you know in higher rpm areas. HP is work over time so we know the most airflow over time into the engine has to increase in order to make more power. So if porting hurts their ability to hold/create more pressure how is it possible they make more power? The problem would have to be a overall flow restriction if that were true right?
@DodgyBrothersEngineering
4 жыл бұрын
JaegerWrenching often the greatest most effective flow gains come from redistribution of air rather than just making things bigger. Best way to explain that is to get you to watch this video. kzitem.info/news/bejne/yY6mm5ikenebgYo The Chevy 292 head is very similar to our Holden 6 head (it is a bigger version of it, but exact same problems). In the video you see him removing the bolt bosses... If he stopped right here this would kick the living crap out of the low speed air flow. The ports of these heads are siamesed, meaning one opening feeds two intake valves in two different cylinders, so while one intake valve is open the other is closed. This makes a big open pocket behind the valve. Opening up that area makes a bad problem even worse, because it looses even more air speed / velocity at low valve lifts (when the engine hasn't got much suck going on). Later in the video you see him with a piece of alloy in his hand, now he is actually going to reduce the intake runner volume by placing this piece of alloy in the bottom of the port floor (these heads flow really really bad at low valve lifts) so by building up the floor he has reduced the total volume of the port (even though he took out the boss) but he has lifted and contoured the floor which will dramatically improves low air speed in the port, because he reduced the total volume of air not increased it. Ford 4V heads could run into a similar problem, unless you wanted to use them for anything other than wide open throttle, some head shops would put material back into the heads in specific spots. You can go too big which is also detrimental to your end game. It might flow more air on a flow bench at wide open throttle (remember this air on a flow bench is being sucked through with a big pump, not pushed), but it makes the power delivery of everything under wide open throttle severely compromised. Check out this video on my channel at 9 minutes 40 kzitem.info/news/bejne/pmNtyYGVnZtzbKg you can see two different dyno charts, very similar engines but completely different power outputs, one is linear (mine), steady and consistent, and the other one is completely gutless till all of a sudden it gets a big whack of boost. So what is different about them? Airflow. OK let's see if I can explain this properly... I think it was you that used a straw example, but couldn't find it in the video. If you blow through a reasonable sized straw (not one of those tiny ones), you have good even flow and pressure, because the cross sectional area of the straw remains constant throughout the entire length of the straw, so there is nothing to disturb the air flow (no venturis). Now imagine an exhaust system where the headers have a 3" collector, the individual pipes are all the same size (say 1.75" primaries) but then they suddenly go from being 1.75" to 3". Remember what I said early about what happens when you go from small to big? You lose pressure but increase flow proportionally. Then lets say it then has to go through a 2" section of pipe (pressure increases, flow decreases) and then back to 3" (pressure decreases, flow increases). The problem with all this up and down big and small is that once air stalls (loses velocity / speed) it can't be simply started again, without fresh air pushing it along, and you wind up with a pulsing effect. So what I am trying to demonstrate here is that a straight pipe of x size can potentially outflow a bigger pipe that goes up and down in sizes. You need to look at the blower with a similar view. What is the greatest point of restriction? Obviously where the rotors move the air along the cavity (note I didn't say compress because these blowers don't compress they simply move air) having a big area before or after the rotors is only going to do one thing. Lose all air speed like the head example, and give you sluggish response, where it has to wait for the valve to fully open to get the flow happening. Just like an exhaust system you want the exiting air to create a scavenging effect. You want that outgoing air to pull through the fresh air, go too big on the exhaust primary diameter and the air speed can stall, or worse cause reversion (where the air stops completely and tries to back flow towards the cylinder). Notice on dyno tests they often add a small 12" - 18" pipe to the end of the headers, this is to aid the scavenging of the cylinder. More restriction in this case means more hp. Intake manifolds follow the same principles, go too big with the runners, and all low end power goes bye bye. Great for flat out WOT, but useless to drive to the shops. Hopefully I have managed to get the idea across big is not always better, you also don't want too small either that will strangle the flow too. What you are trying to achieve is an even flow through the entire engine start to finish from the throttle body to the exhaust tip. Somewhere in there is your answer to your question. On the intake side you may need to actually put material back... Start at you air filter, is it big enough to supply (and more) the pipe connected to it? Look at the throttle body, is the throttle body going to be a huge restriction to the inlet pipe attached to it? look at the blower, is the area directly behind the throttle body way too big, which will cause air flow to drop? Can this area be improved but straightening out the air in some spots? Does the total volume need to be reduced? Remember the straw, what we are ultimately aiming for is the correct sized straw through the entire system. Often factory casting as compromised for several reasons. Firstly build costs, spending money on getting the inlet right might be of little consideration, if I can get 90% of the air flow for $100 less per unit. Secondly bolts, bosses and other things that need to bolt to it. Sometimes compromises are made to a design to add a bracket for something else like a kick down cable for a transmission. I have no doubts small gains can be had, but they won't come through any increase in swept volume, they will come from being smart with the air pressure and flow. I think I had it back to front they will probably gain on the top end at the cost of the bottom end (provided changes are useful), and it will still lose efficiency causing more heat.
@DodgyBrothersEngineering
4 жыл бұрын
At 7:48 you get a better look at the bottom. The bypass valve area might be long enough. Imagine that you filled that area where the bypass valve is with water, but not so much that it tries to spill into the bypass hole (I'm not going to say epoxy because I don't know if it would crack and fall out, or if it would expand and crack the aluminum, so I'll say water because your not going to fit it back to the engine with water in there). If you flatten that whole area out but still left the bypass valve operational, you would be doing something similar to what you might want to look at on the intake. reducing the total volume so instead of it trying to swirl the air around in a useless cavity, you keep the sectional area volume the same. Which helps distribute the air across the entire intercooler core. The other big difference between yours and many of the other blowers out there, is you have an intercooler directly after the blower outlet. The intercooler core is always going to be a much bigger restriction that just dumping the air into a big open area. Therefore you need to be mindful of how much air you allow to escape back into the inlet side of the blower. Remember the bike pump, if you put your thumb over the outlet, and if the sealing washer is weak (which by design these blowers are) it will bypass the pseudo seal and leak back creating mucho grande heat. The other blowers without the intercooler are relying on air speed to push up against the last lot of air to make boost, but that will be happening down near the valves not right at the blower. If you have a restriction right near the blower (like say an intercooler) you increase that risk of back flow. If it was my blower and I was trying to improve the efficiency, I would probably make a 4mm or 5mm plate cut a hole the right size for the bypass valve and tack weld in non distort areas the plate into place. I would dyno test before and after changing nothing. Often people claim big gains after making a change but they forget to mention they changed the pulley size at the same time, or they changed this or that. You wouldn't need that area to be fully welded just a couple of tack, so it could be removed if it made things worse.
@grumpysteelman
4 жыл бұрын
Dodgy - I agree with most of this. However, I think that you missed making one point - those silencer slots have been found to increase boost pressure if they are blocked off. The KZitemr said that he’d port the silencers. That’s obviously no bueno, but my understanding is that some of the rotor outlet shaping is also about case rigidity and what works as a casting vs what additional machining would cost is a factor in most of the OE designs. Remember that you made the argument that the engineers wouldn’t give up efficiency - well maybe - but why do we modify anything then? Easy answer - in a perfect world, trade-offs still have to be made. Bypass valves serve lots of purpose in fuel efficiency, cruising noise, etc. but you give up a little responsiveness and cycle air around the blower in a loop. We also must realize that engineers are people too and it is possible that they left something on the table. It’s like comparing the M122 blower to a TVS1900. They were made at the same time but the TVS is a generation ahead - why still make the M series of blowers? Cuz reasons! Beyond that, I appreciate that you have a greater understanding of these blowers. I won’t nitpick your post, but I do disagree on a few more points. Ultimately though, setting a muppets loose with sanding discs and carbide burrs probably doesn’t work out as well as people would want to think. Incidentally, I have 3 of the M122 blowers from the XLR-V engines and I believe the two largest improvements come from spinning the blower to 18k and increasing the throttle body up to at least 92mm. In the OE configuration they split an ~82 throttle body into a Y at the back of the engine, hug the blower to the front, then exit off toward the driver’s side headlight. Engineers are people too.
@darrenharris2978
6 жыл бұрын
Like information bro
@lavergadezambada
6 жыл бұрын
Posi race ports ftw
@JaegerWrenching
6 жыл бұрын
yeah i've heard posi ports make the most!
@lavergadezambada
6 жыл бұрын
JaegerWrenching he’s a cool dude too if you decide to port your own blower he’ll give you tips
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