Supercharging questions search didnt answer
12-12-04, 08:54 PM
#1
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Supercharging questions search didnt answer
OK i have been looking twords superchargering my N/A and searched here and google and still have a few small questiosn that werent answered.
OK Im planning on a getting a thunderbird supercharger fabbed onto my 13b. It is a stock rebuild with no porting. I am also going to be putting headers on to complete my open exaust , later this month. so here are my questions
1) do i need any modifications to my exaust and or 5/6 ports prior to supercharging?
2) Can boost from a supercharger be controlled and/or read like boost from a turbo?
3) is it true that supercharging increases low end much more so than high end power, but high end shold ahve a small increase as well? This is the general impression i got in my 1.5 hours of reading.
4) what would be the minimum and maximum psi i could/should look for when shopping for a supercharger for my engine?
If i missed these answers in my search im sorry and I accept your flame but nay help would be appreciated.
OK Im planning on a getting a thunderbird supercharger fabbed onto my 13b. It is a stock rebuild with no porting. I am also going to be putting headers on to complete my open exaust , later this month. so here are my questions
1) do i need any modifications to my exaust and or 5/6 ports prior to supercharging?
2) Can boost from a supercharger be controlled and/or read like boost from a turbo?
3) is it true that supercharging increases low end much more so than high end power, but high end shold ahve a small increase as well? This is the general impression i got in my 1.5 hours of reading.
4) what would be the minimum and maximum psi i could/should look for when shopping for a supercharger for my engine?
If i missed these answers in my search im sorry and I accept your flame but nay help would be appreciated.
12-12-04, 09:05 PM
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Originally Posted by I EAT CIVICS
1) do i need any modifications to my exaust and or 5/6 ports prior to supercharging?
2) Can boost from a supercharger be controlled and/or read like boost from a turbo?
3) is it true that supercharging increases low end much more so than high end power, but high end shold ahve a small increase as well? This is the general impression i got in my 1.5 hours of reading.
4) what would be the minimum and maximum psi i could/should look for when shopping for a supercharger for my engine?
2. No, i dont think so.
3. Superchargers generally boost more low than high, but it will boost high as well.
4. i have no idea.
12-12-04, 09:08 PM
#3
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Originally Posted by BlueSteel
1. I think the 5/6 ports are activated by something in the exhaust, but im not sure.
2. No, i dont think so.
3. Superchargers generally boost more low than high, but it will boost high as well.
4. i have no idea.
2. No, i dont think so.
3. Superchargers generally boost more low than high, but it will boost high as well.
4. i have no idea.
12-12-04, 09:17 PM
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Your boost levels depend on the supercharger and pulley size.
You control your boost with different pulley sizes usually, not sure if there is another way.
You can hook a boost gauge up to a supercharged vehicle. Hell you could put one on a non-boosted engine if you really wanted to.
Your torque curve depends on the supercharger, but a supercharger does not suffer from turbo lag, so the power is pretty much instant. Superchargers typically add more power down low than up top.
BTW- Beating Civics is nothing to be proud of.
You control your boost with different pulley sizes usually, not sure if there is another way.
You can hook a boost gauge up to a supercharged vehicle. Hell you could put one on a non-boosted engine if you really wanted to.
Your torque curve depends on the supercharger, but a supercharger does not suffer from turbo lag, so the power is pretty much instant. Superchargers typically add more power down low than up top.
BTW- Beating Civics is nothing to be proud of.
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12-12-04, 09:19 PM
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Wow! Please, do not attempt to supercharge your cars until you know more about them.
A) a superchargers boost is controlled generally by pulley size
B) the aux ports depend upon how you set it up, if you use a TII lower intake manifold or custom, just remove them, or wire them open
C) Yes, it does add low-end torque, but the top end suffers
D) the thunderbird charger is an Eaton m90 (1.3l/rev)
E) you'll have to relocate your throttle body if you even want to get this to function *properly*, You will then have to create a custom intake manifold for the air to travel into after exiting the charger (hopefully after coming out of an intercooler of sorts)
F) You can read boost just like any other vehicle
G) Sizing the charger is what basically determines the boost, you're not going to be able to aim for a 'target' psi since each charger will move a different ammount of air.
A) a superchargers boost is controlled generally by pulley size
B) the aux ports depend upon how you set it up, if you use a TII lower intake manifold or custom, just remove them, or wire them open
C) Yes, it does add low-end torque, but the top end suffers
D) the thunderbird charger is an Eaton m90 (1.3l/rev)
E) you'll have to relocate your throttle body if you even want to get this to function *properly*, You will then have to create a custom intake manifold for the air to travel into after exiting the charger (hopefully after coming out of an intercooler of sorts)
F) You can read boost just like any other vehicle
G) Sizing the charger is what basically determines the boost, you're not going to be able to aim for a 'target' psi since each charger will move a different ammount of air.
12-12-04, 09:28 PM
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Ok, supercharging just like any other form of manifold pressure can be read. Just like vaccuum, boost (or positive intake manifold pressure) can be read by a gauge connected to the manifold. A supercharger can also benefit from a blow-off valve, just like a turbo although the fact that the supercharger is belt driven makes it less of an issue. A supercharger makes more low end torque because being belt driven allows it to reach it's maximum output at a lower RPM because it's not dependent on exhaust pressure to drive it. This also means that it will top out at a lower RPM than a turbo and can be overdriven. To adjust the torque curve of a supercharger you have to adjust pulley sizes to move the peak output where you want it. Anytime you pump more air into an engine you need more fuel so plan on some kind of fuel controller to increase flow as well as a good boost sensitive fuel regulator to increase fuel pressure over boost so you dont go lean & fry your motor. The max boost you should be looking at is about 10psi, the higher the boost the more you shorten your engine's life. As far as the 5/6 ports, it depends on what year your engine is. If you have an S4 they're driven off the exhaust pressure, if you have an S5 they're driven off the airpump. With a supercharger you probably dont need to worry about the activation because you'll have plenty of low end.
The problem with supercharging + turbo charging aside from the complexity of such a system, is the fact that you can't dissengage the supercharger once the turbo comes up to speed. People have done it but it's not the ideal situation. Most worried about turbo "lag" use nitrous on the bottom end to get the turbo spooled quicker or you can run staggered turbos using a smaller turbo to spool quickly and a larger turbo to come on at a higher RPM.
The problem with supercharging + turbo charging aside from the complexity of such a system, is the fact that you can't dissengage the supercharger once the turbo comes up to speed. People have done it but it's not the ideal situation. Most worried about turbo "lag" use nitrous on the bottom end to get the turbo spooled quicker or you can run staggered turbos using a smaller turbo to spool quickly and a larger turbo to come on at a higher RPM.
12-12-04, 09:29 PM
#10
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Originally Posted by SonicRaT
Wow! Please, do not attempt to supercharge your cars until you know more about them.
A) a superchargers boost is controlled generally by pulley size
B) the aux ports depend upon how you set it up, if you use a TII lower intake manifold or custom, just remove them, or wire them open
C) Yes, it does add low-end torque, but the top end suffers
D) the thunderbird charger is an Eaton m90 (1.3l/rev)
E) you'll have to relocate your throttle body if you even want to get this to function *properly*, You will then have to create a custom intake manifold for the air to travel into after exiting the charger (hopefully after coming out of an intercooler of sorts)
F) You can read boost just like any other vehicle
G) Sizing the charger is what basically determines the boost, you're not going to be able to aim for a 'target' psi since each charger will move a different ammount of air.
A) a superchargers boost is controlled generally by pulley size
B) the aux ports depend upon how you set it up, if you use a TII lower intake manifold or custom, just remove them, or wire them open
C) Yes, it does add low-end torque, but the top end suffers
D) the thunderbird charger is an Eaton m90 (1.3l/rev)
E) you'll have to relocate your throttle body if you even want to get this to function *properly*, You will then have to create a custom intake manifold for the air to travel into after exiting the charger (hopefully after coming out of an intercooler of sorts)
F) You can read boost just like any other vehicle
G) Sizing the charger is what basically determines the boost, you're not going to be able to aim for a 'target' psi since each charger will move a different ammount of air.
1) Does anyone have or know of a writeup that could detail the Tb relocation suggested above?
2)what 6 port arrangement would be better? I am aiming for a higher low end above all. I currently am in the process of fully electropneumatic 6 port actuation at around 3800rpms.
12-12-04, 09:33 PM
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Uhm, wow. There are no write-ups on the TB relocation, because it's all custom. I ended up using an oversized aftermarket unit off of an enlarged inlet plenum (I'm also using an MP ported blower). Remove the aux ports, better flow. Now let me comment on that post above.
12-12-04, 09:37 PM
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Originally Posted by vintagespeed
Ok, supercharging just like any other form of manifold pressure can be read. Just like vaccuum, boost (or positive intake manifold pressure) can be read by a gauge connected to the manifold. A supercharger can also benefit from a blow-off valve, just like a turbo although the fact that the supercharger is belt driven makes it less of an issue.
There's absolutely NO need for a blow-off valve on an eaton m90. The throttle body is *SUPPOSED* to sit *INFRONT* of the charger, so that when it snaps shut, the charger just spins in a vacuum, which compresses no air, so there is no surge, thus no need for a BOV. Zbrowns setup was horribly inefficient and done improperly, yes it worked, but definatly not well. There is also a bypass, so when the engine draws vacuum it opens an extra port allowing air to bypass the charger (what little is drawn into the charger anyway with the plates closed). This is all stuff you'll need to think about.
12-12-04, 09:39 PM
#13
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Originally Posted by SonicRaT
Uhm, wow. There are no write-ups on the TB relocation, because it's all custom. I ended up using an oversized aftermarket unit off of an enlarged inlet plenum (I'm also using an MP ported blower). Remove the aux ports, better flow. Now let me comment on that post above.
12-12-04, 09:47 PM
#14
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Originally Posted by BDoty311
BTW- Beating Civics is nothing to be proud of.
BTW I hate the name, i just made it up quick one day when i came across a post in a google search and wanted to reply. months later when i decided to join i realized i already had an account and dont wanna use anothe email so im stuck.
12-12-04, 09:49 PM
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Basically you're on your own at the moment, I'm the only other forum member (that I can find) with a properly setup eaton m90, zbrown got rid of his, and I don't really have any pictures/etc to show. Wozzoom was trying, not sure if he's finished his yet. He might be able to provide some insight.
12-12-04, 09:56 PM
#16
For the auxillary ports, I would just keep them working. Instead of running them off of exhaust or airpump pressure depending on what year model you have, I would run the signal to the intake manifold. Have them open when you are under boost only. This way when you are not under boost they are shut and you have better off boost low end and mileage. The M90 uses a bypass valve so there is no boost when the engine isn't under load. This setup would work very nice.
Since the bypass valve opens to relieve boost pressure when not under load, why not control it in much the same way a boost controller controls a wastegate? Use the pulley size that will give you the highest desired boost level and then devise a way to control this valve so that it can bleed off some pressure when you don't want it this high. Theoretically this could work.
Here's a picture of a fairly simple way to install one. This is not mine BTW. This unit is a M62 which is too small but the technique used could be applied to the M90. This person maintained the stock mid and lower manifold but used an adapter to bolt the supercharger in place of where the dynamic chamber used to sit. The alternator was relocated. This person had to cut a notch in the firewall to give the supercharger inlet pipe enough room to clear but there are other ways it could have been done. At the very least this should give you some ideas.
Since the bypass valve opens to relieve boost pressure when not under load, why not control it in much the same way a boost controller controls a wastegate? Use the pulley size that will give you the highest desired boost level and then devise a way to control this valve so that it can bleed off some pressure when you don't want it this high. Theoretically this could work.
Here's a picture of a fairly simple way to install one. This is not mine BTW. This unit is a M62 which is too small but the technique used could be applied to the M90. This person maintained the stock mid and lower manifold but used an adapter to bolt the supercharger in place of where the dynamic chamber used to sit. The alternator was relocated. This person had to cut a notch in the firewall to give the supercharger inlet pipe enough room to clear but there are other ways it could have been done. At the very least this should give you some ideas.
Last edited by rotarygod; 12-12-04 at 10:01 PM.
12-12-04, 10:03 PM
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The bypass doesn't flow enough air to function as much more, plus it's vacuum operated, so you'd have to have change that around, and why would you want to 'drop' the boost when you can just put a pulley on that would be just as effective? As for the aux ports, with the roots blower you really don't need them, you'll see positive pressure so early that they'll be useless (trust me, I know, hehe)
12-12-04, 10:05 PM
#18
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I am also going the route of the supercharger sometime in the near future. Although I'm a 1st gen guy I intend on swapping an S4 13B before I go with the blower. I'm also using the slightly more efficent, higher-rpm biased M-62. This is a smaller eaton, but I'm looking for no more than 7 PSI and not really interested in any top-end gain at all. The reason I see my project being successful is that I'm setting very low, reasonable goals. To start I'm going to attempt without an intercooler, blow-though (I know it isn't ideal, and I'll deal with that below) and running a 1:1 drive ratio. I'm going to be using some sort of Gilmer drive system so I don't have to put too much tension on the front-bearing. I'm also going to be using a Megasquirt stand-alone with a locked distributer, so fuel won't be an issue and I have a WB O2 so tuning shouldn't be too hard.
In case you haven't noticed I've thought through this much more than the average "I wanna SC my car" poster. Problems I see with this set-up are:
1) SC is too small, not likely because it pushes 10 PSI on a 3.4L V6 pathfinder I believe. Also this SC may indeed even have a clutch which might add an interesting variable.
2) TB is on the wrong side, I'm going to be running a boost guage between the SC and the TB and will monitor pressures built in off-boost conditions; if the by-pass can't regulate the pressures then I will switch to a draw-though. Because I'm pushing relatively little boost this may not be a problem, we'll see.
3) Intake air too hot, because I'm running Megasquirt though a lap-top during the tuning process I will have precise info with regards to intake temp so hopefully I can add some accurate numbers to see just how hot these eaton blowers run. If this is a problem I'm investigating both water-injection and propane-injection, of course an intercooler is also a possiblity.
Basically I intend to succeed because my measure of success is much more realistic and because I'm building up the complete system. If anyone has any other input (SonicRaT your first hand input is great) then please by all means bash away.
Cheers,
Grant
In case you haven't noticed I've thought through this much more than the average "I wanna SC my car" poster. Problems I see with this set-up are:
1) SC is too small, not likely because it pushes 10 PSI on a 3.4L V6 pathfinder I believe. Also this SC may indeed even have a clutch which might add an interesting variable.
2) TB is on the wrong side, I'm going to be running a boost guage between the SC and the TB and will monitor pressures built in off-boost conditions; if the by-pass can't regulate the pressures then I will switch to a draw-though. Because I'm pushing relatively little boost this may not be a problem, we'll see.
3) Intake air too hot, because I'm running Megasquirt though a lap-top during the tuning process I will have precise info with regards to intake temp so hopefully I can add some accurate numbers to see just how hot these eaton blowers run. If this is a problem I'm investigating both water-injection and propane-injection, of course an intercooler is also a possiblity.
Basically I intend to succeed because my measure of success is much more realistic and because I'm building up the complete system. If anyone has any other input (SonicRaT your first hand input is great) then please by all means bash away.
Cheers,
Grant
12-12-04, 10:16 PM
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Haha, I've got a megasquirt sitting on the floor of my '87 sport. Well, the problem with the blow through is that you're CONSTANTLY drawing power from the engine, you're ALWAYS trying to build boost, the poor chargers going to be working 24/7, even if there's nothing on the other end it's still going to have to push that air around, which will hurt. Also, the bypass really isn't big enough to bypass that much air, and the chargers free to compress whatever it can suck in, just remember that. You'll also need some sort of BOV or similar (unless your bypass is big enough to manage this on it's own?) Because the entire time the engine winds down it's going to be spitting compressed air at a wall. This is why this setup is so bad.
12-12-04, 10:17 PM
#20
Originally Posted by SonicRaT
The bypass doesn't flow enough air to function as much more, plus it's vacuum operated, so you'd have to have change that around, and why would you want to 'drop' the boost when you can just put a pulley on that would be just as effective? As for the aux ports, with the roots blower you really don't need them, you'll see positive pressure so early that they'll be useless (trust me, I know, hehe)
12-12-04, 10:23 PM
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This is true, but maintaing a speed with them open really doesn't exert that much more on the engine, or hurt gas mileage. I actually got curious one day and decided to try that out with servo actuated aux ports, once I got cruising I left them open for a nice 4 hour highway drive, closed them on the way back and the gas mileage was the same. Since they don't really choke the engine in the higher band being open, and generally gas mileage sux in the low band with them open during accelerating, I didn't find much need for them, but I definatly see what you're talking about, I just don't believe them to be very functional in that sense.
12-12-04, 10:34 PM
#22
I guess one thing I didn't consider is what rpm you are at on the freeway. It's pretty close to the point where they open anyways depending on how you drive and maybe above it. I suppose it wouldn't do much leaving them closed. The n/a needs them closed to get good low end power but as you've pointed out, the supercharger more than makes up for that. It might do something at lower speeds but probably not much after all.
12-12-04, 10:35 PM
#23
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I am intending to use a DSM BOV (because they're cheap like me!) for the first set-up. Now if in theory the BOV can vent enough air to the upwind (if that makes sense) side of the SC then the SC shouldn't be compressing anything and virtually no additional power-loss should be seen. I will of course be running a closed loop BOV to reduce pumping-loss in this case. My only worry is that because the up-wind side of the SC won't be seeing vacumme it may indeed be significantly less efficient. Needless to say I'm willing to fiddle with it and redesign if neccessary, but I think with my low-boost set-up it may not be neccessary. Also I will be keeping the 5&6th ports open to reduce complication. My end-goal is to increase the low-end and mid-range significantly while keeping the top-end similar and being able to run on 87-89 octane fuel. Although the car is destined mainly for street-driving and recreational AutoX (we don't really do classes around here, I'm in ModC anyway). Basically I'm just looking for a little extra push from the bottom end.
Thanks for the input,
Grant
Thanks for the input,
Grant
12-12-04, 10:40 PM
#24
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Well, it's still going to be trying to push air through a little 1.5" hole (if that? maybe 1.25?", which is going to create a bit of backpressure, so it'll drag on the engine, how much nobody knows for certain. We shall see!
12-12-04, 11:06 PM
#25
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We will see, as far as I know nobody has connected a boost guage between the blower and the TB. If it pushes more than a few PSI then I know I will be loosing significant power. The ghetto way of solving this would be to run multiple BOVs (which I may try) and I will also run the stock by-pass as well. But if it all comes down to it, I might just relocate the TB and be done with it; however I won't go that extreme intill I have the change to get some real numbers on it. Also I was wondering where everybody was mounting these and what type of belt/pulleys they are using? In the picture above it looks like a surpentine belt.
Grant
Grant