Discussion
I'd like to try twin charging (super and turbo charged)
Its for a Volvo Amazon project I got
I plan on using a Mercedes M111 2.3 Kompressor with Megasquirt 3 ecu
So i was thinking of using the Supercharger that comes already on the 2.3k engines with the clutch system, having it switched off at idle to save on fuel and wear etc, engaged at say for example 1500rpm using a megasquirt output feeding into the turbo intake helping it spool up quicker, once the turbo is sucking more air than the supercharger can provide switch off the supercharger with the clutch system to stop it making heat and sapping power higher up the rpm range, between the supercharger and turbo have a Y pipe, one side with an air filter, one to the turbo intake and one for the supercharger side have and electronic throttle body also connected up to the megasquirt switching the whole supercharger side off diverting air for the turbo straight from the air filter.
Is there a better self adjusting using some sort of vacuum system for the switch over?
Will I need a intercooler/charge cooler between the supercharger and turbo or will just after the tubo be enough?
Im not great at explaining things but in my head I think it makes sense?
I know its over complicated and just one turbo will be fine, but where's the fun and challenge in that?
Any tips greatly appreciated
Its for a Volvo Amazon project I got
I plan on using a Mercedes M111 2.3 Kompressor with Megasquirt 3 ecu
So i was thinking of using the Supercharger that comes already on the 2.3k engines with the clutch system, having it switched off at idle to save on fuel and wear etc, engaged at say for example 1500rpm using a megasquirt output feeding into the turbo intake helping it spool up quicker, once the turbo is sucking more air than the supercharger can provide switch off the supercharger with the clutch system to stop it making heat and sapping power higher up the rpm range, between the supercharger and turbo have a Y pipe, one side with an air filter, one to the turbo intake and one for the supercharger side have and electronic throttle body also connected up to the megasquirt switching the whole supercharger side off diverting air for the turbo straight from the air filter.
Is there a better self adjusting using some sort of vacuum system for the switch over?
Will I need a intercooler/charge cooler between the supercharger and turbo or will just after the tubo be enough?
Im not great at explaining things but in my head I think it makes sense?
I know its over complicated and just one turbo will be fine, but where's the fun and challenge in that?
Any tips greatly appreciated
few points that spring to mind:
1) saving wear and fuel "at idle" is, unless you are an OEM trying to best the official emissions tests cycles, completely pointless. Spinning a s/c at idle isn't an issue because it's doing no work. In fact, you just will wear out the clutch, and cause yourself all sorts of issues with trying to get a smooth boost progression etc
2) What you do to bypass the S/C at high flows really depends on the type of S/C you use. For a positive displacement charger with no internal compression (ie roots type) then you can just leave it spinning round and have a passive (or active) air bypass around it. For a S/C with internal compression (various screw types / rotrex's etc then you will loose a small amount of power in the work done via compression if you use a full bypass, but in reality, the losses are pretty small.
3) You can easily suck or blow through the compressor of a turbocharger, so generally don't need to bypass that, however the oil seals inside won't thank you for being pressurised on the inlet.
4) Boost control is complex. Although you can make it work with simple "switched" logic (say pressure switches etc) it'll be pretty sh*t by modern standards. Better to use FBW throttle, and control to a pre-throttle air density target, using an active S/C bypass and careful w/g control of the turbo (modern engines use electronic w/g actuation to avoid issues with min/max boost line etc
Have fun!
1) saving wear and fuel "at idle" is, unless you are an OEM trying to best the official emissions tests cycles, completely pointless. Spinning a s/c at idle isn't an issue because it's doing no work. In fact, you just will wear out the clutch, and cause yourself all sorts of issues with trying to get a smooth boost progression etc
2) What you do to bypass the S/C at high flows really depends on the type of S/C you use. For a positive displacement charger with no internal compression (ie roots type) then you can just leave it spinning round and have a passive (or active) air bypass around it. For a S/C with internal compression (various screw types / rotrex's etc then you will loose a small amount of power in the work done via compression if you use a full bypass, but in reality, the losses are pretty small.
3) You can easily suck or blow through the compressor of a turbocharger, so generally don't need to bypass that, however the oil seals inside won't thank you for being pressurised on the inlet.
4) Boost control is complex. Although you can make it work with simple "switched" logic (say pressure switches etc) it'll be pretty sh*t by modern standards. Better to use FBW throttle, and control to a pre-throttle air density target, using an active S/C bypass and careful w/g control of the turbo (modern engines use electronic w/g actuation to avoid issues with min/max boost line etc
Have fun!
Max_Torque said:
few points that spring to mind:
1) saving wear and fuel "at idle" is, unless you are an OEM trying to best the official emissions tests cycles, completely pointless. Spinning a s/c at idle isn't an issue because it's doing no work. In fact, you just will wear out the clutch, and cause yourself all sorts of issues with trying to get a smooth boost progression etc
2) What you do to bypass the S/C at high flows really depends on the type of S/C you use. For a positive displacement charger with no internal compression (ie roots type) then you can just leave it spinning round and have a passive (or active) air bypass around it. For a S/C with internal compression (various screw types / rotrex's etc then you will loose a small amount of power in the work done via compression if you use a full bypass, but in reality, the losses are pretty small.
3) You can easily suck or blow through the compressor of a turbocharger, so generally don't need to bypass that, however the oil seals inside won't thank you for being pressurised on the inlet.
4) Boost control is complex. Although you can make it work with simple "switched" logic (say pressure switches etc) it'll be pretty sh*t by modern standards. Better to use FBW throttle, and control to a pre-throttle air density target, using an active S/C bypass and careful w/g control of the turbo (modern engines use electronic w/g actuation to avoid issues with min/max boost line etc
Have fun!
It would be a lot easier just to blow the turbos through the supercharger.1) saving wear and fuel "at idle" is, unless you are an OEM trying to best the official emissions tests cycles, completely pointless. Spinning a s/c at idle isn't an issue because it's doing no work. In fact, you just will wear out the clutch, and cause yourself all sorts of issues with trying to get a smooth boost progression etc
2) What you do to bypass the S/C at high flows really depends on the type of S/C you use. For a positive displacement charger with no internal compression (ie roots type) then you can just leave it spinning round and have a passive (or active) air bypass around it. For a S/C with internal compression (various screw types / rotrex's etc then you will loose a small amount of power in the work done via compression if you use a full bypass, but in reality, the losses are pretty small.
3) You can easily suck or blow through the compressor of a turbocharger, so generally don't need to bypass that, however the oil seals inside won't thank you for being pressurised on the inlet.
4) Boost control is complex. Although you can make it work with simple "switched" logic (say pressure switches etc) it'll be pretty sh*t by modern standards. Better to use FBW throttle, and control to a pre-throttle air density target, using an active S/C bypass and careful w/g control of the turbo (modern engines use electronic w/g actuation to avoid issues with min/max boost line etc
Have fun!
To do it the other way around is just strange unless the physical installation is also very odd.
stevieturbo said:
Max_Torque said:
few points that spring to mind:
1) saving wear and fuel "at idle" is, unless you are an OEM trying to best the official emissions tests cycles, completely pointless. Spinning a s/c at idle isn't an issue because it's doing no work. In fact, you just will wear out the clutch, and cause yourself all sorts of issues with trying to get a smooth boost progression etc
2) What you do to bypass the S/C at high flows really depends on the type of S/C you use. For a positive displacement charger with no internal compression (ie roots type) then you can just leave it spinning round and have a passive (or active) air bypass around it. For a S/C with internal compression (various screw types / rotrex's etc then you will loose a small amount of power in the work done via compression if you use a full bypass, but in reality, the losses are pretty small.
3) You can easily suck or blow through the compressor of a turbocharger, so generally don't need to bypass that, however the oil seals inside won't thank you for being pressurised on the inlet.
4) Boost control is complex. Although you can make it work with simple "switched" logic (say pressure switches etc) it'll be pretty sh*t by modern standards. Better to use FBW throttle, and control to a pre-throttle air density target, using an active S/C bypass and careful w/g control of the turbo (modern engines use electronic w/g actuation to avoid issues with min/max boost line etc
Have fun!
It would be a lot easier just to blow the turbos through the supercharger.1) saving wear and fuel "at idle" is, unless you are an OEM trying to best the official emissions tests cycles, completely pointless. Spinning a s/c at idle isn't an issue because it's doing no work. In fact, you just will wear out the clutch, and cause yourself all sorts of issues with trying to get a smooth boost progression etc
2) What you do to bypass the S/C at high flows really depends on the type of S/C you use. For a positive displacement charger with no internal compression (ie roots type) then you can just leave it spinning round and have a passive (or active) air bypass around it. For a S/C with internal compression (various screw types / rotrex's etc then you will loose a small amount of power in the work done via compression if you use a full bypass, but in reality, the losses are pretty small.
3) You can easily suck or blow through the compressor of a turbocharger, so generally don't need to bypass that, however the oil seals inside won't thank you for being pressurised on the inlet.
4) Boost control is complex. Although you can make it work with simple "switched" logic (say pressure switches etc) it'll be pretty sh*t by modern standards. Better to use FBW throttle, and control to a pre-throttle air density target, using an active S/C bypass and careful w/g control of the turbo (modern engines use electronic w/g actuation to avoid issues with min/max boost line etc
Have fun!
(i say you can blow or suck through a compressor, but the seals won't thank you for being blown! ie, it's better to suck thorough......)
Ok I'm all ears and appreciate comments
The S/c will most likely be a Eaton M45 or a M65 and from I can work out the M65 has a bypass built into the attachment, would it be worthwhile to make use of this? The turbo will most likely be around GT2871/GT3071 size, based on that info would you still have the turbo blow through the s/c?
Thanks
The S/c will most likely be a Eaton M45 or a M65 and from I can work out the M65 has a bypass built into the attachment, would it be worthwhile to make use of this? The turbo will most likely be around GT2871/GT3071 size, based on that info would you still have the turbo blow through the s/c?
Thanks
OP, i suggest reading and understanding this:
rootssuperchargerwiki
and working out what this tells you:
eatonm62map
and then doing some basic sums to work out the approximate sizing and drive ratio you will need, and the start looking at the turbo graphs:
(Hint, roots type blowers are NOT compressors. they simple move a fixed volume of the working fluid from their inlet to their output everytime they revolve once. The "compression" is entirely a result of trying to force more air into the engine that can actually flow through it at any given moment, and hence the actual compression efficiency is poor because it is not adiabatic.)
if i were doing this, (although tbh, i would just use a modern VVT turbocharger (or possibly a staged pair of turbos)) i'd want an electronic throttle and proportional electronic s/c bypass valve, i'd aim to control pre-throttle air density with a blended control strategy depending on engine rpm that acts to modulate the bypass valve opening area and the turbo wastegate position. With a roots positive displacement S/C, it doesn't care what the air density at it's inlet is. It will move volume "x" from inlet to output just the same no matter what the inlet density. So in effect the T/C can just act to precharge the supercharger, and the s/c bypass is only required for accurate part load control.
rootssuperchargerwiki
and working out what this tells you:
eatonm62map
and then doing some basic sums to work out the approximate sizing and drive ratio you will need, and the start looking at the turbo graphs:
(Hint, roots type blowers are NOT compressors. they simple move a fixed volume of the working fluid from their inlet to their output everytime they revolve once. The "compression" is entirely a result of trying to force more air into the engine that can actually flow through it at any given moment, and hence the actual compression efficiency is poor because it is not adiabatic.)
if i were doing this, (although tbh, i would just use a modern VVT turbocharger (or possibly a staged pair of turbos)) i'd want an electronic throttle and proportional electronic s/c bypass valve, i'd aim to control pre-throttle air density with a blended control strategy depending on engine rpm that acts to modulate the bypass valve opening area and the turbo wastegate position. With a roots positive displacement S/C, it doesn't care what the air density at it's inlet is. It will move volume "x" from inlet to output just the same no matter what the inlet density. So in effect the T/C can just act to precharge the supercharger, and the s/c bypass is only required for accurate part load control.
Edited by anonymous-user on Thursday 29th September 21:09
chuntington101 said:
Max, what about your mates rocket box that he was developing a few years ago? Could that not be used?
Despite what you might think, the combustor ALS isn't actually that useful outside of some particular cases, one of them being WRC (aggressive inlet restricted, low average speed, low friction motorsport, where response and downspeeding can deliver a faster car).For most racing, if you much better being at WOT at 7000rpm and making twice the power than being at WOT at 3500rpm.......
And for a road car, the complexities and heat management issues are serious too. I actually ran a Bugeye scoob with the system on the road for while whilst at Prodrive and it:
1) had to have a "danger jet blast" sticker next to the exhaust, but it still set fire to the rear bumper fairly regularity
and
2) Gave the transmission such a work out that it eventually sheared the output shaft clean off the back of the transfer case one day after a rather too spirited attempt to make progress from a set of traffic lights with the system engaged.......
chuntington101 said:
Also Max, how would you do the sequential turbos? One big and one small? Or two small turbos? What about control of the turbos? Is there anything that could but taken off production stuff?
Imo, ^^^this is right answer, although we are on the edge of making a proper electric fill in turbo a practical option (really needs 42V electrics to get enough power density, even for just doing in-fill boosting)However with modern engines with high Compression ratios, variable valve timing and intake systems, and of course, multi speed super rapid shifting transmissions, lag really isn't the issue it once was. ie, in the 100ms whilst you nail the accelerator to the floor, the tranny will be dropping 4 gears anyway, so making loads of boost immediately isn't actually that useful. Engines like the current turbo 6's in the 911 range prove that, if you don't care about costs so much, gasoline VGT turbine housings almost eradicate significant lag with just one turbo charger.
The sizing choice really depends on the engine layout and what you are trying to achieve. With V engines, it makes some sense to route all the exhaust through one turbine at low engine speeds, then into two as the revs rise, particularly with "hotside" (turbos in the engine V) layouts.
Workfare the responses Max! For cars without super fast shifting trans and lower tech engines how would you do a sequential setup? Could you parts rob stuff off say a BMW and make it work? Or would you simply compound boost the turbos (large turbo feeding a smaller one)?
Appreciate the 'correct' answer would be to fit a proper gearbox. Just wondering how / if it could be done.
Appreciate the 'correct' answer would be to fit a proper gearbox. Just wondering how / if it could be done.
chuntington101 said:
Workfare the responses Max! For cars without super fast shifting trans and lower tech engines how would you do a sequential setup? Could you parts rob stuff off say a BMW and make it work? Or would you simply compound boost the turbos (large turbo feeding a smaller one)?
Appreciate the 'correct' answer would be to fit a proper gearbox. Just wondering how / if it could be done.
It depends on the engine architecture. For a simple inline 4 cyl id probably send all the exhaust into the small turbine, fit that with a nice big wastegate, and use that to bypass the small turbocharger and send the exhaust into the big turbine. The compressors can probably just be straight compounded in series. The trick will be in the accurate control of the first (small turbine) wastegate, to limit the max pressure ratio across that turbine to limit max shaft speed to within sensible limits, before handing over to the big turbine (which will also need a wastegate/bypass, unless you are going truly massive! These days, it would make a lot of sense to use an electronic wastegate actuator, certainly for the smaller gate around the primary turbine.Appreciate the 'correct' answer would be to fit a proper gearbox. Just wondering how / if it could be done.
This is Kevin's...drag application obviously but doing roughly what Max says.
http://www.yellowbullet.com/forum/showthread.php?t...
http://www.yellowbullet.com/forum/showthread.php?t...
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