Cheap Supecharger Plans
08-18-2015, 12:59 AM
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Cheap Supecharger Plans
Hey all,
Joined specifically to dump some information and bounce some ideas off some more knowledgeable folk. I have a 2001 XJ with an AW4 auto, and, most relevant, just rolled it over to 290k miles. I call her Miley for that reason, as well as the fact that her butt sags a bit, lol. I'll be headed back to school where I have access to CNC plasma cutters, MIG/TIG/SMAW welders and all the skills to use and abuse them. It's at about 5,000 feet elevation and, while Miley doesn't ever really lack power, I feel that the low-end torque of a supercharger will make wheeling a blast on those public logging roads (...all my friends are Toyota people, Miley and I want to eat those rigs for lunch).
I recently got my hands on a junkyard Eaton M90 out of a Grand Prix 3800 V6. $50. I planned to throw it onto the 91 Suburban I had at the time, just to get that gutless PoS to move up hills faster than 15 miles per hour. I've decided that a better donor would be Miley herself, before promptly getting rid of old Lucy the 'Burban.
SO. Here's what I know.
> Eaton M90 can push probably 4-10 lbs, depending on pulley application; I expect a pretty significant reduction on a larger 6-cylinder motor. Positive displacement at 1.02L per revolution.
> Miley's got 290k and as much as I don't want to blow a head gasket, I don't rip on the poor girl like a lot of other wheelers, I find joy in tact & finesse both on- and off-road.
> The 2001 model XJ didn't carry 19 lb/hr injectors, but rather 22.5 lb/hr injectors.
> OBDII would mean I'd likely need a piggyback ECU.
> The A/C compressor is out and runs R134A.
> I want to relocate the battery & coolant overflow reservoir to the driver's side and remove the factory airbox, remove the obsolete A/C, and mount up the supercharger to the A/C bracket.
That being said, I have a few questions, primarily with tuning and fuel delivery; I'm very much familiar with engine & supercharger operation, do a whole lot of backyard/garage mechanic work, but the nuances of tuning are incredibly complex to me.
> Most upgrade the 19 lb/hr injectors to Ford 24 lb/hr. Would that be necessary with a 22.5 lb/hr injector set?
My reasoning is that, from what I think I understand, these injectors run on a cycles per second basis. If these injectors are, say, capped at 100 cycles per second and in stock form only runs, for instance, 80 cycles per second at WOT, perhaps supercharging the intake air would bring it to 90, closer to that cap of 100, and I wouldn't be running lean? This could also be a fundamental misunderstanding of injector operation on my part. Feel free to clear that up for me.
> If I don't have a choice but to run a piggyback ECU, that'll be the most expensive part in the system. Got any experience with any of them under, perhaps, $300? (...Yes. I'm stingy and I'm here to challenge you.) I also know that reflashing an ECU is another option, and I'd be willing to look into that as well.
> If I run a larger pulley for smaller amounts of boost, I can machine more 6-rib pulleys to different sizes to slowly step up the boost. There's no shortage of round stock at school, it's always an option. Would that allow me to run stock injectors?
> For a twin-scroll, Roots-type supercharger, as the M90 is, the throttle body needs to be placed upstream of the supercharger. What are the ramifications of this? It'll sense the same amount of air before compression, and will have to add more fuel to compensate for the added pressure. I suppose this is why a piggyback system would be needed. Is there a way to get a throttle body that can understand and read boost, and meter fuel as a result?
Any questions, I'll share what I can. Otherwise, this cheap build will start by late September and I'll keep a detailed price list of what I need, as well as lots of pictures.
Thanks,
John
Joined specifically to dump some information and bounce some ideas off some more knowledgeable folk. I have a 2001 XJ with an AW4 auto, and, most relevant, just rolled it over to 290k miles. I call her Miley for that reason, as well as the fact that her butt sags a bit, lol. I'll be headed back to school where I have access to CNC plasma cutters, MIG/TIG/SMAW welders and all the skills to use and abuse them. It's at about 5,000 feet elevation and, while Miley doesn't ever really lack power, I feel that the low-end torque of a supercharger will make wheeling a blast on those public logging roads (...all my friends are Toyota people, Miley and I want to eat those rigs for lunch).
I recently got my hands on a junkyard Eaton M90 out of a Grand Prix 3800 V6. $50. I planned to throw it onto the 91 Suburban I had at the time, just to get that gutless PoS to move up hills faster than 15 miles per hour. I've decided that a better donor would be Miley herself, before promptly getting rid of old Lucy the 'Burban.
SO. Here's what I know.
> Eaton M90 can push probably 4-10 lbs, depending on pulley application; I expect a pretty significant reduction on a larger 6-cylinder motor. Positive displacement at 1.02L per revolution.
> Miley's got 290k and as much as I don't want to blow a head gasket, I don't rip on the poor girl like a lot of other wheelers, I find joy in tact & finesse both on- and off-road.
> The 2001 model XJ didn't carry 19 lb/hr injectors, but rather 22.5 lb/hr injectors.
> OBDII would mean I'd likely need a piggyback ECU.
> The A/C compressor is out and runs R134A.
> I want to relocate the battery & coolant overflow reservoir to the driver's side and remove the factory airbox, remove the obsolete A/C, and mount up the supercharger to the A/C bracket.
That being said, I have a few questions, primarily with tuning and fuel delivery; I'm very much familiar with engine & supercharger operation, do a whole lot of backyard/garage mechanic work, but the nuances of tuning are incredibly complex to me.
> Most upgrade the 19 lb/hr injectors to Ford 24 lb/hr. Would that be necessary with a 22.5 lb/hr injector set?
My reasoning is that, from what I think I understand, these injectors run on a cycles per second basis. If these injectors are, say, capped at 100 cycles per second and in stock form only runs, for instance, 80 cycles per second at WOT, perhaps supercharging the intake air would bring it to 90, closer to that cap of 100, and I wouldn't be running lean? This could also be a fundamental misunderstanding of injector operation on my part. Feel free to clear that up for me.
> If I don't have a choice but to run a piggyback ECU, that'll be the most expensive part in the system. Got any experience with any of them under, perhaps, $300? (...Yes. I'm stingy and I'm here to challenge you.) I also know that reflashing an ECU is another option, and I'd be willing to look into that as well.
> If I run a larger pulley for smaller amounts of boost, I can machine more 6-rib pulleys to different sizes to slowly step up the boost. There's no shortage of round stock at school, it's always an option. Would that allow me to run stock injectors?
> For a twin-scroll, Roots-type supercharger, as the M90 is, the throttle body needs to be placed upstream of the supercharger. What are the ramifications of this? It'll sense the same amount of air before compression, and will have to add more fuel to compensate for the added pressure. I suppose this is why a piggyback system would be needed. Is there a way to get a throttle body that can understand and read boost, and meter fuel as a result?
Any questions, I'll share what I can. Otherwise, this cheap build will start by late September and I'll keep a detailed price list of what I need, as well as lots of pictures.
Thanks,
John
08-18-2015, 01:09 AM
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Talk to http://jeepm62superchargerkit.blogspot.com/ he could sell everything but the blower.But before you do it i would look to see if you have the cracking head or not the 00-01s got on them.
08-19-2015, 08:57 AM
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Thanks for the plug.
Spend a few hours reading all the pages on my site. This will help a lot.
Supercharging the Jeep 4.0L engine has great rewards. It is a fairly simple engine and basic electronics.
The injectors are pulsed and not cycles/sec. The injectors are pulsed once every engine cycle(2 revolutions). They are pulsed a different amount in milliseconds depending how much fuel is needed. The are basically on-off. The ecu commands how much on time they stay open, in milliseconds.
You need to set some parameters/goals.
For your high mileage engine it needs to be in top running condition. Check compression, oil pressure, ignition, exhaust, etc. Best is new O2 sensors.
Max boost I would recommend for your engine is 5-6 pounds. Any more and you are asking for trouble. The M62 can handle this. The M90 would have to be pulley'd down.
The M62 is easier packaging vs the M90 unless you are using the Ford M90.
There are some great books out there on supercharging. Read them all.
In the end, it is really easier to buy a complete kit ready to go rather than trying to re-invent the wheel. Either way, it's all a great learning experience and fun.
Spend a few hours reading all the pages on my site. This will help a lot.
Supercharging the Jeep 4.0L engine has great rewards. It is a fairly simple engine and basic electronics.
The injectors are pulsed and not cycles/sec. The injectors are pulsed once every engine cycle(2 revolutions). They are pulsed a different amount in milliseconds depending how much fuel is needed. The are basically on-off. The ecu commands how much on time they stay open, in milliseconds.
You need to set some parameters/goals.
For your high mileage engine it needs to be in top running condition. Check compression, oil pressure, ignition, exhaust, etc. Best is new O2 sensors.
Max boost I would recommend for your engine is 5-6 pounds. Any more and you are asking for trouble. The M62 can handle this. The M90 would have to be pulley'd down.
The M62 is easier packaging vs the M90 unless you are using the Ford M90.
There are some great books out there on supercharging. Read them all.
In the end, it is really easier to buy a complete kit ready to go rather than trying to re-invent the wheel. Either way, it's all a great learning experience and fun.
08-21-2015, 11:26 PM
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Hey, thanks Cobra! I've followed a couple of your thread replies, they're excellent and insightful.
New question just came up. I'll definitely consider buttoning up the engine to do this mod. However, an interesting question arose between my friends and I: if I upgrade to ARP head studs to replace the stock ones, is there a torque sequence I can follow that would allow me to decompress and recompress the head gasket without having to replace it?
Doing a google search on "replacing head studs without changing head gasket" gives me the reverse, lol. Turns out everyone wants to know if they have to change head studs when replacing a head gasket, and here I am wanting to replace head studs without touching the gasket. It's not that it's out of my capability, but if I can avoid having to tear both manifolds off and switching out gaskets by, say, replacing one head stud at a time and following the 3-step torque process, I'd like to avoid it if I could. And of course, replacing the studs with ARP would just be for that added safety factor so as not to turn the head into an 85 lb. rectangular cannonball.
I'll definitely do more research on the topic. I can't really find much on whether those 22.5 lb/hr injectors are just well-oversized for their stock application and can be coupled with a few pounds of boost. Any insight on that?
-John
New question just came up. I'll definitely consider buttoning up the engine to do this mod. However, an interesting question arose between my friends and I: if I upgrade to ARP head studs to replace the stock ones, is there a torque sequence I can follow that would allow me to decompress and recompress the head gasket without having to replace it?
Doing a google search on "replacing head studs without changing head gasket" gives me the reverse, lol. Turns out everyone wants to know if they have to change head studs when replacing a head gasket, and here I am wanting to replace head studs without touching the gasket. It's not that it's out of my capability, but if I can avoid having to tear both manifolds off and switching out gaskets by, say, replacing one head stud at a time and following the 3-step torque process, I'd like to avoid it if I could. And of course, replacing the studs with ARP would just be for that added safety factor so as not to turn the head into an 85 lb. rectangular cannonball.
I'll definitely do more research on the topic. I can't really find much on whether those 22.5 lb/hr injectors are just well-oversized for their stock application and can be coupled with a few pounds of boost. Any insight on that?
-John
08-22-2015, 01:49 AM
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Before you do anything i would look and see if you have the cracking head or not,The good head will say TUPY between the 3rd and 4th cylinder rockers the cracking head says nothing there.If its the good head i believe you might get away with just replacing the head bolts.If the cracking head i would think hard about replacing it.
08-22-2015, 02:15 AM
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290k engine ...
So at 12.5 pounds boost, I 'popped' a head gasket at like 170k. The area that went was the front corner that is torqued 10lb-ft less than all the other bolts, it threads into a water passage. On inspection of the gasket, it was corroded and ready to 'rot' thru even before the boost. I replaced it with a MLS Victor Reinz gasket and new stock replacement VR head bolts.
If you don't want to pull the head and 'do it right', I would probably just try and check and retorque to spec, without loosening, what you have. I don't think pulling each bolt out and replacing with a new bolt is such a good idea. Unloading and reloading the head and gasket can't be good. Or just say what the heck and just run what you have.
The 22.5 pound injectors are barely more than stock and will not support any boost.
Stock are like 21 lb (x6=126lb total) and good for stock 190HP or 0.66lb/hp of fuel.
1 pound of boost will add about 6% more power. On our 4.0L that is about 12HP/pound boost.
So 4 pounds boost will add about 24% more power and will require 24% more fuel. And to add 48HP (4 pounds boost) x 0.66 lb/hp = 31.7 pounds of fuel / 6 injectors = 5.3 lbs more fuel per injector needed for 4 pounds of boost.
So you will need like 21+5=26 minimum injector size. Reality is you get 30lb/hr injectors and then have some room to grow.
So at 12.5 pounds boost, I 'popped' a head gasket at like 170k. The area that went was the front corner that is torqued 10lb-ft less than all the other bolts, it threads into a water passage. On inspection of the gasket, it was corroded and ready to 'rot' thru even before the boost. I replaced it with a MLS Victor Reinz gasket and new stock replacement VR head bolts.
If you don't want to pull the head and 'do it right', I would probably just try and check and retorque to spec, without loosening, what you have. I don't think pulling each bolt out and replacing with a new bolt is such a good idea. Unloading and reloading the head and gasket can't be good. Or just say what the heck and just run what you have.
The 22.5 pound injectors are barely more than stock and will not support any boost.
Stock are like 21 lb (x6=126lb total) and good for stock 190HP or 0.66lb/hp of fuel.
1 pound of boost will add about 6% more power. On our 4.0L that is about 12HP/pound boost.
So 4 pounds boost will add about 24% more power and will require 24% more fuel. And to add 48HP (4 pounds boost) x 0.66 lb/hp = 31.7 pounds of fuel / 6 injectors = 5.3 lbs more fuel per injector needed for 4 pounds of boost.
So you will need like 21+5=26 minimum injector size. Reality is you get 30lb/hr injectors and then have some room to grow.
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08-24-2015, 08:59 AM
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Thanks for the insight guys. I'll go look into some larger injectors, I know for a fact I can snag some from the junkyard for nearly nothing but a box of donuts . Any thoughts on what will fit?
08-24-2015, 09:48 AM
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The 22.5 pound injectors are barely more than stock and will not support any boost.
Stock are like 21 lb (x6=126lb total) and good for stock 190HP or 0.66lb/hp of fuel.
1 pound of boost will add about 6% more power. On our 4.0L that is about 12HP/pound boost.
So 4 pounds boost will add about 24% more power and will require 24% more fuel. And to add 48HP (4 pounds boost) x 0.66 lb/hp = 31.7 pounds of fuel / 6 injectors = 5.3 lbs more fuel per injector needed for 4 pounds of boost.
So you will need like 21+5=26 minimum injector size. Reality is you get 30lb/hr injectors and then have some room to grow.
The injectors are pulsed and not cycles/sec. The injectors are pulsed once every engine cycle(2 revolutions). They are pulsed a different amount in milliseconds depending how much fuel is needed. The are basically on-off. The ecu commands how much on time they stay open, in milliseconds.
The 22.5 pound injectors are barely more than stock and will not support any boost.
Stock are like 21 lb (x6=126lb total) and good for stock 190HP or 0.66lb/hp of fuel.
1 pound of boost will add about 6% more power. On our 4.0L that is about 12HP/pound boost.
So 4 pounds boost will add about 24% more power and will require 24% more fuel. And to add 48HP (4 pounds boost) x 0.66 lb/hp = 31.7 pounds of fuel / 6 injectors = 5.3 lbs more fuel per injector needed for 4 pounds of boost.
So you will need like 21+5=26 minimum injector size. Reality is you get 30lb/hr injectors and then have some room to grow.
The injectors are pulsed and not cycles/sec. The injectors are pulsed once every engine cycle(2 revolutions). They are pulsed a different amount in milliseconds depending how much fuel is needed. The are basically on-off. The ecu commands how much on time they stay open, in milliseconds.
08-24-2015, 03:55 PM
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ECU is hard coded for the pulse width timing. It has a little wiggle room to get it to 14.7 but not richer for the supercharger needs.
08-24-2015, 05:13 PM
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08-24-2015, 07:33 PM
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There are a few piggy backs that can work to control bigger injectors.
No chips, there are 2 guys that can reprogram the ecu but $$$.
Christuned.com and FlynRyan. Both frequent jeepstrokers.com
No chips, there are 2 guys that can reprogram the ecu but $$$.
Christuned.com and FlynRyan. Both frequent jeepstrokers.com
Last edited by CobraMarty; 08-25-2015 at 07:05 AM.
08-24-2015, 08:01 PM
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New developments:
Interestingly enough, the junkyards I scour most often don't have many vehicles past the year 1998, but my family back home happens to have a 2000 Plymouth Neon and a replacement engine, as well as a dozen or so fuel injectors. I had been doing research and only discovered this injector swap today, so that felt pretty damn cool! Research has told me that they run at about 24.5 lbs/hr at 49 PSI, and many have claimed that they run too rich for their tastes; others use them for stroker motors, saying they have "no business being in a stock motor," so perhaps I've found my donor set of injectors. At this point it's all one big science experiment. It may not benefit everyone in the sense of being "cheap," as it seems I'm finding some pretty coincidental deals, but if it works, hey...I'll have a part list to dig into and perhaps some alternatives to find. I'll find out what part numbers these suckers are and dig through more junkyards in the area for 2000s Chrysler vehicles.
Interestingly enough, the junkyards I scour most often don't have many vehicles past the year 1998, but my family back home happens to have a 2000 Plymouth Neon and a replacement engine, as well as a dozen or so fuel injectors. I had been doing research and only discovered this injector swap today, so that felt pretty damn cool! Research has told me that they run at about 24.5 lbs/hr at 49 PSI, and many have claimed that they run too rich for their tastes; others use them for stroker motors, saying they have "no business being in a stock motor," so perhaps I've found my donor set of injectors. At this point it's all one big science experiment. It may not benefit everyone in the sense of being "cheap," as it seems I'm finding some pretty coincidental deals, but if it works, hey...I'll have a part list to dig into and perhaps some alternatives to find. I'll find out what part numbers these suckers are and dig through more junkyards in the area for 2000s Chrysler vehicles.
08-29-2015, 01:08 PM
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Probably as tight a fit as I'll ever see.
Remove A/C and all related lines; relocate battery to airbox location, remove airbox; relocate coooant overflow to opposite side, or lower, because this M90 has ports for coolant (intercooler? Bearing cooler?)
Junkyard throttle body and A/C compressor mount, to measure up some spacers to fit the supercharger.
