A check valve for the map sensor, along with a rising rate fuel pressure regulator tuned accordingly would work great and cheap for low boost. Or a 3 bar map sensor. Unless it has a MAF sensor.
Home grown turbo jocks - stupid questions from ...
- Thread starter Gary Allan
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I'm going simple (if I get this worked out at all). I'm checking to see if the SRT MAP uses the same index voltage as mine. This is setup to read boost. Some have reported frying their PCM using adjustable MAP sensors. Beyond that ..I really shouldn't need much in fuel management. The PCM should increment or decrement the premapped fuel curve as needed with the adaptive cells. No piggyback systems or whatnot. Fuel pressure regulation may come into it. Again, I'm only looking to bring normal peak output into a more sensible rpm range.
I'm sure there will be complications, but even 8" W.C. above the throttle plate should provide substantial gains in this engine. If the AIS can cope with that in terms of idle control, then the job should be done.
This job amounts to being within a couple of hundred bucks of some enlarged throttle body (premanufactured). Those basically re-index your throttle geometry for about $400. You basically get more effective throttle opening for the same pedal application. Users perceive more low end power. This should sorta do the same thing except accomplish it via added volume metric efficiency staying just ahead of the engine's air demand.
It does appear to be a lot of work for the limited number of ponies that I seek, but the $/hp ratio is good for this engine.
I've checked out the links. One post mentioned some company (didn't give the name) that appears to have managed to remap the DC PCM. If that could be done while retaining 100% OBDII compliance and only required some tweaking to the fuel system, then that would be a viable option.
I need transparent reliability and no impact on longevity. I'm not going to be pulling this engine in 60k due to blowing a hole through a piston due to detonation in the learning curve. The engine itself can probably sustain much higher hp levels with 100% reliability, but the hoops you have to jump through to get refined fuel management without making a career in "tunin'" as a life goal makes it beyond what I'm willing to go through for the popular use of a turbo.
If anyone sees some obvious holes in my reasoning here, let me know. Keep in mind that I don't have a problem going to great lengths to accomplish very little. I don't need it to make sense in the way most people look at it. This still needs to be a 250k engine.
I'm sure there will be complications, but even 8" W.C. above the throttle plate should provide substantial gains in this engine. If the AIS can cope with that in terms of idle control, then the job should be done.
This job amounts to being within a couple of hundred bucks of some enlarged throttle body (premanufactured). Those basically re-index your throttle geometry for about $400. You basically get more effective throttle opening for the same pedal application. Users perceive more low end power. This should sorta do the same thing except accomplish it via added volume metric efficiency staying just ahead of the engine's air demand.
It does appear to be a lot of work for the limited number of ponies that I seek, but the $/hp ratio is good for this engine.
I've checked out the links. One post mentioned some company (didn't give the name) that appears to have managed to remap the DC PCM. If that could be done while retaining 100% OBDII compliance and only required some tweaking to the fuel system, then that would be a viable option.
I need transparent reliability and no impact on longevity. I'm not going to be pulling this engine in 60k due to blowing a hole through a piston due to detonation in the learning curve. The engine itself can probably sustain much higher hp levels with 100% reliability, but the hoops you have to jump through to get refined fuel management without making a career in "tunin'" as a life goal makes it beyond what I'm willing to go through for the popular use of a turbo.
If anyone sees some obvious holes in my reasoning here, let me know. Keep in mind that I don't have a problem going to great lengths to accomplish very little. I don't need it to make sense in the way most people look at it. This still needs to be a 250k engine.
You're not thinking about using a T3/T4 turbo are you? What's that line from Full Metal Jacket? Too boocoo...
Don't bother with an external wastegate, they're all too big for your app. When you get to 400bhp then think about one. Internal wastegate... much simpler...
Turbo'ed 4.0L's are more popular. Find out what they do for fuel control? A rising rate FPR and/or Apexi Safc should work. iirc, you can change injectors sizes without changing the ecu if you change to the correct MAP sensor.
http://www.jpmagazine.com/techarticles/engine/154_0508_jeep_4_0l_turbo/index.html
http://www.cartech.net/jeepturbo.htm
custom turbo manifold w/ weld-els, Weirtech will do custom flanges
http://www.sdsefi.com/techheader.htm how-to
http://www.honda-tech.com/zerothread?id=2073179 flanges for cheap (Weirtech)
http://www.jgstools.com/turbo/index2.html some kits
http://homemadeturbo.com/tech_projects/adapter_plate_tech/index.html adapter plate how-to
Don't bother with an external wastegate, they're all too big for your app. When you get to 400bhp then think about one. Internal wastegate... much simpler...
Turbo'ed 4.0L's are more popular. Find out what they do for fuel control? A rising rate FPR and/or Apexi Safc should work. iirc, you can change injectors sizes without changing the ecu if you change to the correct MAP sensor.
http://www.jpmagazine.com/techarticles/engine/154_0508_jeep_4_0l_turbo/index.html
http://www.cartech.net/jeepturbo.htm
custom turbo manifold w/ weld-els, Weirtech will do custom flanges
http://www.sdsefi.com/techheader.htm how-to
http://www.honda-tech.com/zerothread?id=2073179 flanges for cheap (Weirtech)
http://www.jgstools.com/turbo/index2.html some kits
http://homemadeturbo.com/tech_projects/adapter_plate_tech/index.html adapter plate how-to
Originally Posted By: gtx510
You're not thinking about using a T3/T4 turbo are you? What's that line from Full Metal Jacket? Too boocoo...
Don't bother with an external wastegate, they're all too big for your app. When you get to 400bhp then think about one. Internal wastegate... much simpler...
Turbo'ed 4.0L's are more popular. Find out what they do for fuel control? A rising rate FPR and/or Apexi Safc should work. iirc, you can change injectors sizes without changing the ecu if you change to the correct MAP sensor.
http://www.jpmagazine.com/techarticles/engine/154_0508_jeep_4_0l_turbo/index.html
http://www.cartech.net/jeepturbo.htm
custom turbo manifold w/ weld-els, Weirtech will do custom flanges
http://www.sdsefi.com/techheader.htm how-to
http://www.honda-tech.com/zerothread?id=2073179 flanges for cheap (Weirtech)
http://www.jgstools.com/turbo/index2.html some kits
http://homemadeturbo.com/tech_projects/adapter_plate_tech/index.html adapter plate how-to
I agree about the internal wastegate to a point. It worked in some combos I've used but failed miserably in my latest. Boost creep was always an issue with the internal which the Innovative external gate solved. Boost remains steady in every gear.
Being that mine is a V6 with a crossover pipe, mounting an external gate on the crossover pipe to vent three cylinders before they merge into the turbo can yeild a little power too.
I would definately try the internal first if all out power isn't the goal.
You're not thinking about using a T3/T4 turbo are you? What's that line from Full Metal Jacket? Too boocoo...
Don't bother with an external wastegate, they're all too big for your app. When you get to 400bhp then think about one. Internal wastegate... much simpler...
Turbo'ed 4.0L's are more popular. Find out what they do for fuel control? A rising rate FPR and/or Apexi Safc should work. iirc, you can change injectors sizes without changing the ecu if you change to the correct MAP sensor.
http://www.jpmagazine.com/techarticles/engine/154_0508_jeep_4_0l_turbo/index.html
http://www.cartech.net/jeepturbo.htm
custom turbo manifold w/ weld-els, Weirtech will do custom flanges
http://www.sdsefi.com/techheader.htm how-to
http://www.honda-tech.com/zerothread?id=2073179 flanges for cheap (Weirtech)
http://www.jgstools.com/turbo/index2.html some kits
http://homemadeturbo.com/tech_projects/adapter_plate_tech/index.html adapter plate how-to
I agree about the internal wastegate to a point. It worked in some combos I've used but failed miserably in my latest. Boost creep was always an issue with the internal which the Innovative external gate solved. Boost remains steady in every gear.
Being that mine is a V6 with a crossover pipe, mounting an external gate on the crossover pipe to vent three cylinders before they merge into the turbo can yeild a little power too.
I would definately try the internal first if all out power isn't the goal.
Last edited:
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Quote:
Turbo'ed 4.0L's are more popular.
Yes, they are. To get a 2.5 to the power of a stock 4.0 takes more money than doing a 4.0 swap (which is more than just the engine).
Quote:
Find out what they do for fuel control? A rising rate FPR and/or Apexi Safc should work.
More complicated than I need to get ...I think (and it may be quite simple).
Quote:
you can change injectors sizes without changing the ecu if you change to the correct MAP sensor.
It's done often without changing the MAP sensor in NA applications. The 5.0 Mustang #24 injectors are popular.
Great links.
Here's the problem that I (INVARIABLY) run into ..no one seems to be able to think "inside the box". Everyone seems to be unable to detune their thinking to anything below "the edge of the envelope". I will talk to a few vendors/tuners and they'll say "Well you can do xyxz and get up to 12lbs of boost..." ..and I'll come back saying that I don't even need to go much above atmospheric and they'll say something like "why would you want to do something like that?" ...I'll then say that I only need to get about 20-25hp and they'll scratch their heads. None of them deal with these engines where hp is easily in the $75/hp range. They're used to paying $20-$35/hp.
I don't need to "get the most out of it" to make it pay.
To get 25hp out of this engine you need to put in a cam or get the head machined for 1.7:1 ratio rockers. This will keep the thing OBDII compliant. The discontinued MOPAR cams .040 cams almost exactly conform to the current OBDII stock profile with little difference beyond lift. You also go to slightly longer Chevy rods and 305 pistons, but, due to the lack of too many doing this (you're polishing a stout turd), you're on your own on adjusting the quench area to keep things transparent in use and not turning it into a career in "well, NEXT TIME, I'll get the dish pistons instead of the flat tops"...while I've just blown my 5 year budget (for hp) and that's with 3 years of planning (waiting, actually). If you can find them, you can even get bigger OEM valves for a couple of hundred bucks that probably won't do much for you except @ WOT.
So, you've pulled an engine, taken the thing out of service for a bit, spent some money at the machine shop (or paid more to avoid it) and you're at still at a strained 25hp (maybe) and well within range of doing a 4.0 swap with all factory parts.
Meanwhile I can (hopefully) merely do so exhaust work (essentially) do some very minor tweaking (hopefully) and be driving down the road with a 100% hassle free 25-35hp for under a grand.
The hard part is overcoming the insatiable tendency to "get more" from all of the aftermarket support for such things. I'll be running into virtual brick walls of "for another $1000 (or $2500 worth of DYI hoop jumping in equivalent time) you can get some REAL gains out of this engine" ..what they don't tell you is that they have a second career in tinkering with it as though this is some life goal akin to the salmon going upstream to spawn. I'm a "set it and forget it" type person.
Again, with just about any other engine on the planet, this would not make sense. Most of them come with more hp/liter to begin with then I can achieve in any legally streetable manner with this engine.
Figure it this way, I'm taking all the money that 9000 other guys throw away with larger throttle bodies and throttle body spacers ..Borla exhausts ...or Magnaflow mufflers ..etc..etc and replacing it with something trick and a little more SOLID yield.
Turbo'ed 4.0L's are more popular.
Yes, they are. To get a 2.5 to the power of a stock 4.0 takes more money than doing a 4.0 swap (which is more than just the engine).
Quote:
Find out what they do for fuel control? A rising rate FPR and/or Apexi Safc should work.
More complicated than I need to get ...I think (and it may be quite simple).
Quote:
you can change injectors sizes without changing the ecu if you change to the correct MAP sensor.
It's done often without changing the MAP sensor in NA applications. The 5.0 Mustang #24 injectors are popular.
Great links.
Here's the problem that I (INVARIABLY) run into ..no one seems to be able to think "inside the box". Everyone seems to be unable to detune their thinking to anything below "the edge of the envelope". I will talk to a few vendors/tuners and they'll say "Well you can do xyxz and get up to 12lbs of boost..." ..and I'll come back saying that I don't even need to go much above atmospheric and they'll say something like "why would you want to do something like that?" ...I'll then say that I only need to get about 20-25hp and they'll scratch their heads. None of them deal with these engines where hp is easily in the $75/hp range. They're used to paying $20-$35/hp.
I don't need to "get the most out of it" to make it pay.
To get 25hp out of this engine you need to put in a cam or get the head machined for 1.7:1 ratio rockers. This will keep the thing OBDII compliant. The discontinued MOPAR cams .040 cams almost exactly conform to the current OBDII stock profile with little difference beyond lift. You also go to slightly longer Chevy rods and 305 pistons, but, due to the lack of too many doing this (you're polishing a stout turd), you're on your own on adjusting the quench area to keep things transparent in use and not turning it into a career in "well, NEXT TIME, I'll get the dish pistons instead of the flat tops"...while I've just blown my 5 year budget (for hp) and that's with 3 years of planning (waiting, actually). If you can find them, you can even get bigger OEM valves for a couple of hundred bucks that probably won't do much for you except @ WOT.
So, you've pulled an engine, taken the thing out of service for a bit, spent some money at the machine shop (or paid more to avoid it) and you're at still at a strained 25hp (maybe) and well within range of doing a 4.0 swap with all factory parts.
Meanwhile I can (hopefully) merely do so exhaust work (essentially) do some very minor tweaking (hopefully) and be driving down the road with a 100% hassle free 25-35hp for under a grand.
The hard part is overcoming the insatiable tendency to "get more" from all of the aftermarket support for such things. I'll be running into virtual brick walls of "for another $1000 (or $2500 worth of DYI hoop jumping in equivalent time) you can get some REAL gains out of this engine" ..what they don't tell you is that they have a second career in tinkering with it as though this is some life goal akin to the salmon going upstream to spawn. I'm a "set it and forget it" type person.
Again, with just about any other engine on the planet, this would not make sense. Most of them come with more hp/liter to begin with then I can achieve in any legally streetable manner with this engine.
Figure it this way, I'm taking all the money that 9000 other guys throw away with larger throttle bodies and throttle body spacers ..Borla exhausts ...or Magnaflow mufflers ..etc..etc and replacing it with something trick and a little more SOLID yield.
BuickGN, I think Gary's power increase will be very modest compared to yours. I bet you're running way more boost than he wants.
Gary,
Most turbo shops are going to have more experience with high-power apps. You want something that makes about 5-8psi? Even at those lower boost levels you'll want to think about fuel/timing control for maximum reliability. You could try trolling around on rockcrawler forums as I've seen some torquey turbo set-ups from them.
Do you want more low-end torque also? Or just more midrange to high-end power?
Do you have to worry about emissions/smog testing? A turbo kit will fail a visual check if you have those. You should be able to make it pass a sniffer test no problem, just make sure the CAT is hot.
I think you could find a junkyard/used turbo (and intercooler) that would work well for your 2.5L. I'd lean more towards Garrett because they're common and cheap to upgrade or repair, Mitsubishi (MHI) would be my 2nd choice.
A Nissan/Garrett from a Zcar should work well. The L28ET and early VG30ET used T3's, the later VG30ET used a T28.
T3 (not the IHI turbo) from a Ford turbochicken. Some Saab's also used T3's?
http://www.bellengineering.net/Pages/sale_items.html
I don't know if these items are still for sale but they're selling a MSD BTM (p/n 5462) for $80. That should take care of your ignition timing retard under boost. Works with a stock ignition or MSD box.
Will your stock fuel pressure regulator handle boost?
adjustable rate FPR's
http://www.bellengineering.net/Pages/products_FPR.html Cartech copies them
http://www.synapseengineering.com/ newer, cheaper design
S-AFC
The older (1st gen) ones are cheap on ebay (sometimes less than $100) and give you enough fuel control to add slightly larger (~50%) injectors and/or tune the fuel curve for boost.
http://search.ebay.com/apexi-safc
http://search.ebay.com/apexi-s-afc
SAFC in a 4.0L
http://www.jeepsunlimited.com/forums/showthread.php?t=617414
http://www.naxja.org/forum/showthread.php?t=46515
Another thing to think about might be a remote mount turbo?
http://www.jeepforum.com/forum/showthread.php?t=421250
http://www.ststurbo.com/
Or a DIY Eaton (Roots) s/c even though it's less efficient?
http://www.avengersuperchargers.com/ doesn't use Eaton
Gary,
Most turbo shops are going to have more experience with high-power apps. You want something that makes about 5-8psi? Even at those lower boost levels you'll want to think about fuel/timing control for maximum reliability. You could try trolling around on rockcrawler forums as I've seen some torquey turbo set-ups from them.
Do you want more low-end torque also? Or just more midrange to high-end power?
Do you have to worry about emissions/smog testing? A turbo kit will fail a visual check if you have those. You should be able to make it pass a sniffer test no problem, just make sure the CAT is hot.
I think you could find a junkyard/used turbo (and intercooler) that would work well for your 2.5L. I'd lean more towards Garrett because they're common and cheap to upgrade or repair, Mitsubishi (MHI) would be my 2nd choice.
A Nissan/Garrett from a Zcar should work well. The L28ET and early VG30ET used T3's, the later VG30ET used a T28.
T3 (not the IHI turbo) from a Ford turbochicken. Some Saab's also used T3's?
http://www.bellengineering.net/Pages/sale_items.html
I don't know if these items are still for sale but they're selling a MSD BTM (p/n 5462) for $80. That should take care of your ignition timing retard under boost. Works with a stock ignition or MSD box.
Will your stock fuel pressure regulator handle boost?
adjustable rate FPR's
http://www.bellengineering.net/Pages/products_FPR.html Cartech copies them
http://www.synapseengineering.com/ newer, cheaper design
S-AFC
The older (1st gen) ones are cheap on ebay (sometimes less than $100) and give you enough fuel control to add slightly larger (~50%) injectors and/or tune the fuel curve for boost.
http://search.ebay.com/apexi-safc
http://search.ebay.com/apexi-s-afc
SAFC in a 4.0L
http://www.jeepsunlimited.com/forums/showthread.php?t=617414
http://www.naxja.org/forum/showthread.php?t=46515
Another thing to think about might be a remote mount turbo?
http://www.jeepforum.com/forum/showthread.php?t=421250
http://www.ststurbo.com/
Or a DIY Eaton (Roots) s/c even though it's less efficient?
http://www.avengersuperchargers.com/ doesn't use Eaton
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Quote:
BuickGN, I think Gary's power increase will be very modest compared to yours. I bet you're running way more boost than he wants.
This much is certain
Quote:
Most turbo shops are going to have more experience with high-power apps.
Yes, and it will be the most challenging part of this whole project.
Quote:
You want something that makes about 5-8psi?
Maybe not even 1-2 psi. I merely want to move the current peak power point down about 1500 rpm. That is, for the moment ...and assuming 100% VME, my current peak power point is near 210+/- CFM @ 5000 rpm (there abouts). I want to process that CFM through the turbo at about 3200 rpm. The turbo can be anemic beyond that range. This shouldn't require too much in terms of anything fancy. If I never strayed above 3200 rpm (a "what if") I don't see where I should need any additional fuel volume output since the current system already handles this. Now I can up the size of the injectors to handle anything beyond. Beyond that, I think I'll only need an OEM turbo (from, perhaps, a 2.4 turbo) that references (indexes) its output over a vacuum/boost span. I don't think that they expand the logic for their turbo apps. That is, (a number pulled out of my behind) 0v-5v represents 28.8HG to atmospheric vs. 0v-5v representing 28.8HG to +5PSI. The short term and long term adaptives should handle the rest as long as I don't go to far outside the injectors' capability in pulse width expansion to handle the greater density of air. The main thing will be controlling the idle. I need a minor plus for on ramps and some beef for the headwinds. That's about it. I can do it by regearing to 4.10:1 (current is 3.73)..but can cost (potentially) more.
Thanks for the links. They will make decent references.
As you watching can see, my term of "mild" just isn't in anyone's DNA
BuickGN, I think Gary's power increase will be very modest compared to yours. I bet you're running way more boost than he wants.
This much is certain
Quote:
Most turbo shops are going to have more experience with high-power apps.
Yes, and it will be the most challenging part of this whole project.
Quote:
You want something that makes about 5-8psi?
Maybe not even 1-2 psi. I merely want to move the current peak power point down about 1500 rpm. That is, for the moment ...and assuming 100% VME, my current peak power point is near 210+/- CFM @ 5000 rpm (there abouts). I want to process that CFM through the turbo at about 3200 rpm. The turbo can be anemic beyond that range. This shouldn't require too much in terms of anything fancy. If I never strayed above 3200 rpm (a "what if") I don't see where I should need any additional fuel volume output since the current system already handles this. Now I can up the size of the injectors to handle anything beyond. Beyond that, I think I'll only need an OEM turbo (from, perhaps, a 2.4 turbo) that references (indexes) its output over a vacuum/boost span. I don't think that they expand the logic for their turbo apps. That is, (a number pulled out of my behind) 0v-5v represents 28.8HG to atmospheric vs. 0v-5v representing 28.8HG to +5PSI. The short term and long term adaptives should handle the rest as long as I don't go to far outside the injectors' capability in pulse width expansion to handle the greater density of air. The main thing will be controlling the idle. I need a minor plus for on ramps and some beef for the headwinds. That's about it. I can do it by regearing to 4.10:1 (current is 3.73)..but can cost (potentially) more.
Thanks for the links. They will make decent references.
As you watching can see, my term of "mild" just isn't in anyone's DNA
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- Joined
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- Messages
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One hurdle in research overcome.
Quote:
Regardless of whether 1, 2 or 3-Bar MAP sensors are used, each range of MAP sensor still generates a signal between 0.5 to 4.9 vDC, depending on engine load.
For some reason, this is not common knowledge
So, with a bit of connector (possibly) surgery, a 2BAR MAP will appear transparent to my PCM. The MAP merely indexed the same voltage over the span of 1-2 BARS. After the adaptive cells compensate for the wider range of O2 readings compressed into the same span, it should operate in open loop just fine.
Quote:
Regardless of whether 1, 2 or 3-Bar MAP sensors are used, each range of MAP sensor still generates a signal between 0.5 to 4.9 vDC, depending on engine load.
For some reason, this is not common knowledge
So, with a bit of connector (possibly) surgery, a 2BAR MAP will appear transparent to my PCM. The MAP merely indexed the same voltage over the span of 1-2 BARS. After the adaptive cells compensate for the wider range of O2 readings compressed into the same span, it should operate in open loop just fine.
I think if you are gonna up your power you should drop your gears. For example, NA and SC mustangs go up to 3.73s to 4.56s, but the extra load from the longer 3.08s and 3.27s means more distance and more boost per gear. The extra hp would make up for the longer gears too.
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I'm already turning 3200 rpm @ 70mph w/3.73 gears- w/235/75r15. They're over 28" in diameter. I don't like the piston speed and distance per mile that I have now.
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I've got to be from some other dimension!! Really!! I just can't find anyone to speak my language.
If I had a dime for every time that I've heard this statement
Q:"Why would you want to do something like that"?
A:"Why do you need to know? Does it alter the physics of what I want to do"?
While no one appears to see the sense in it ..they also haven't a clue (at least apparently) how to reason it either. That is, they can't even articulate the "non-sensibility" of it in an intelligent manner. "Well, you really can't do that due to the blablablabla. What you would end up with is a blblablabla" ..but they just don't know and can't even muster an experienced "guess" in terms of suggestive actions.
Why do I always fall into the realm of uncharted territory? Always at the location where "you can't get there from here"?? Just what is it with me??
I've got to really check which portal address I dial in from now on. I've obviously stumbled into the wrong parallel universe.
Read what the guru of an alleged turbo site tells me.
Gary, I used a aerocharger 53 on a 3 cyl chevy sprint engine, the only goal was to maintain sealevel hp at altitude, no more. Ran into the same "why not more" thinking you mention.
Last edited:
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How much trouble did you have tweaking it? What hoops did you jump through and how many prefabbed (as from a vendor) parts did you have to buy? Just interested. I'm sure that I'll pay to have it look "pretty" ..but getting it functional should be cheap enough. The current rhetoric says that I need a very small turbo to have it producing anything @ the 2500-3200 range that I desire.
Lot of trouble. It was in an kit airplane (veri-ez) so everything was fabbed. The turbo and carb was sourced from motorcycle kit so very little of the plumbing worked. Was trying to keep the whole thing packaged in the fuselage without adding any bulges that might slow the plane. Fueling was big problem even though the HP should have been close, the car motor just needed a lot of fuel to cool. Burned electrodes right off plugs and EGT probes it ran so hot. Then fought detonation and had to rethink the whole timing advance boost retard scenero. In the end the 3 cyl vibrated too much and gave up on it. Next engine was a used Japanese crate turbo suburu converted to mechanical FI to lose all the wires and make it easier to tune. It worked, but the plane had bulges.
Originally Posted By: Gary Allan
How much trouble did you have tweaking it? What hoops did you jump through and how many prefabbed (as from a vendor) parts did you have to buy? Just interested. I'm sure that I'll pay to have it look "pretty" ..but getting it functional should be cheap enough. The current rhetoric says that I need a very small turbo to have it producing anything @ the 2500-3200 range that I desire.
Originally Posted By: Gary Allan
How much trouble did you have tweaking it? What hoops did you jump through and how many prefabbed (as from a vendor) parts did you have to buy? Just interested. I'm sure that I'll pay to have it look "pretty" ..but getting it functional should be cheap enough. The current rhetoric says that I need a very small turbo to have it producing anything @ the 2500-3200 range that I desire.
Gary,
I recall an SAE paper (had access to the SAE library microfiches at uni, and spent every spare minute there...pre www).
There was one paper on a stored energy supercharging system.
Small electrical compressor, storing compressed air. Above certain throttle openings, the air was released into an "ejector" (like a jet pump on a water bore), a momentum exchange device that converts high head low flow to low head high flow.
Picked up a pound or two boost, for about the duration of an overtaking manouever.
I know it wouldn't help with your wide overlap cam, but it's another way of skinning the feline.
I recall an SAE paper (had access to the SAE library microfiches at uni, and spent every spare minute there...pre www).
There was one paper on a stored energy supercharging system.
Small electrical compressor, storing compressed air. Above certain throttle openings, the air was released into an "ejector" (like a jet pump on a water bore), a momentum exchange device that converts high head low flow to low head high flow.
Picked up a pound or two boost, for about the duration of an overtaking manouever.
I know it wouldn't help with your wide overlap cam, but it's another way of skinning the feline.
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How about "compressor braking"?? Fill a tank on waste motion ..use it for boost ...or in a hybrid ...reverse the process (open new reed valves - close others) and provide power??
If you cut injectors then use the throttle as a brake, you could charge up to 200-250psi fairly safely on compression....excess then gets blown out a relief valve providing braking, Would be a real anti muscle memory learning curve. More throttle means more braking.
Swagelok makes a lot of really neat compression fitted stuff that could help.
Swagelok makes a lot of really neat compression fitted stuff that could help.
Originally Posted By: Gary Allan
One hurdle in research overcome.
Quote:
Regardless of whether 1, 2 or 3-Bar MAP sensors are used, each range of MAP sensor still generates a signal between 0.5 to 4.9 vDC, depending on engine load.
For some reason, this is not common knowledge
So, with a bit of connector (possibly) surgery, a 2BAR MAP will appear transparent to my PCM. The MAP merely indexed the same voltage over the span of 1-2 BARS. After the adaptive cells compensate for the wider range of O2 readings compressed into the same span, it should operate in open loop just fine.
Wouldn't the ecu see a different voltage for the same amount of vacuum if you changed from a 2 to 3 bar MAP sensor? Or 1 to 2 bar?
At idle (high vacuum) it would be ok, but before the boost came on the voltages would be different.
Are you still thinking of running 1-2psi?
I'd shot for something more like 5psi, w/ enough fueling to creep to 8psi in cold weather (or w/ less intake/exhaust restriction). And let the size of your compressor limit you hp.
pressure ratio, CR w/ boost, VE, etc...
http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html
One hurdle in research overcome.
Quote:
Regardless of whether 1, 2 or 3-Bar MAP sensors are used, each range of MAP sensor still generates a signal between 0.5 to 4.9 vDC, depending on engine load.
For some reason, this is not common knowledge
So, with a bit of connector (possibly) surgery, a 2BAR MAP will appear transparent to my PCM. The MAP merely indexed the same voltage over the span of 1-2 BARS. After the adaptive cells compensate for the wider range of O2 readings compressed into the same span, it should operate in open loop just fine.
Wouldn't the ecu see a different voltage for the same amount of vacuum if you changed from a 2 to 3 bar MAP sensor? Or 1 to 2 bar?
At idle (high vacuum) it would be ok, but before the boost came on the voltages would be different.
Are you still thinking of running 1-2psi?
I'd shot for something more like 5psi, w/ enough fueling to creep to 8psi in cold weather (or w/ less intake/exhaust restriction). And let the size of your compressor limit you hp.
pressure ratio, CR w/ boost, VE, etc...
http://www.turbobygarrett.com/turbobygarrett/tech_center/tech_center.html
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Quote:
Wouldn't the ecu see a different voltage for the same amount of vacuum if you changed from a 2 to 3 bar MAP sensor? Or 1 to 2 bar?
At idle (high vacuum) it would be ok, but before the boost came on the voltages would be different.
Well, I dunno
I have no index of volume metrics. That is, AFAIK, 2 psi will attain my goal of moving the peak power level down to my usable range (2500-3200) ..or about a 25% reduction in rpm. I'm not sharp enough to integrate the differences in VME based on what I've read. I mean, for all I know 1-2psi is not enough to do what I want to do ..yet I think that 5-15psi is way more (in observed/accepted performance levels of engines that use that range) than I want tweak for. I've really got to manage that cam overlap as not to blow the spent combustion material into the exhaust. I need back pressure to contain this process. Hence, as boost is elevated, so must back pressure. I've got to manage a "collision" of the two forces in balance. Ideally, I'd just, more or less, "keep ahead" of the engine's demand for air and keep a static 1-2psi above the throttle plate and let the intake float at low(er) vacuum while in the range that I need the power. It would be easier to reason if I wasn't so blind. I don't know the VME @ the peak power level where the stock 125+/- @ WOT with the 60mm throttle body and the intake manifold configuration. If I did, then I could integrate that to a CFM ..and then somehow massage that in some manner to move that CFM down about 25% (I think the hp peak is something like 4500rpm - I want it at 3200 rpm). It can totally run out of steam beyond that point and remain flat from 3200 rpm on up and just return to the normal anemic engine that it is.
On the 2 BAR MAP. I'm banking on the adaptive cells in the PCM to reindex the fuel map. What the engine will think, for a bit, is that it's either at way sub-sea level, or at a decent throttle opening. In closed loop it should be just fine using all the inputs (I hope) and this should increment the injector pulse width to compensate. It would do the same thing, over a longer span, (or so I reason) if my injectors clogged to 50% output. It would broaden the pulse width at a given MAP reading to predict a balanced O2 reading.
Now it may not be that simple. I may find that, initially, it runs perfectly fine in closed loop, but can't even idle as the engine switches back and forth between the two states. I still haven't gotten down to the dealer to look at the 2 bar MAP to see how easy it is to integrate it to my manifold/throttle body.
Thanks for the link. It's very informative. I wish there was one of the Garret turbo engineers on the board. It would sure cut out a whole lot of R&D out of the project.
Wouldn't the ecu see a different voltage for the same amount of vacuum if you changed from a 2 to 3 bar MAP sensor? Or 1 to 2 bar?
At idle (high vacuum) it would be ok, but before the boost came on the voltages would be different.
Well, I dunno
On the 2 BAR MAP. I'm banking on the adaptive cells in the PCM to reindex the fuel map. What the engine will think, for a bit, is that it's either at way sub-sea level, or at a decent throttle opening. In closed loop it should be just fine using all the inputs (I hope) and this should increment the injector pulse width to compensate. It would do the same thing, over a longer span, (or so I reason) if my injectors clogged to 50% output. It would broaden the pulse width at a given MAP reading to predict a balanced O2 reading.
Now it may not be that simple. I may find that, initially, it runs perfectly fine in closed loop, but can't even idle as the engine switches back and forth between the two states. I still haven't gotten down to the dealer to look at the 2 bar MAP to see how easy it is to integrate it to my manifold/throttle body.
Thanks for the link. It's very informative. I wish there was one of the Garret turbo engineers on the board. It would sure cut out a whole lot of R&D out of the project.
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