Tiny turbo on a 5.0?
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Tiny turbo on a 5.0?
I've been thinking about what may be a strange idea. I want a tiny turbo, maybe something off of a 2.3 turbo VW, on my 302. That turbo is designed to power the 2.3 from 3000-6000 rpm or so, so it should boost up on the 5.0 from 1400 to 2800.
The idea here is that I'm not actually exceeding the factory fuel system/computer limits...I'm just shooting to flatten out the torque curve of my 302, and make good power down at 2 grand. I don't think i'd need new injectors, MAF, or anything, and at higher RPM's a lot of exhaust would be going through the wastegate
The goal here is simplicity, fuel economy, driveability, and torque. Because the total air at high RPM won't be much more than stock (say 2 psi of boost) the air coming through the MAF (draw-through) won't be too much for the computer to handle. It will just have the ability to suck that much air at any rpm.
Things i'd need to do
-Small turbo after the Y pipe, before the cat.
-Big *** wastegate pipe that bypasses the turbo
-Intercooler & Intake piping
Any thoughts?
The idea here is that I'm not actually exceeding the factory fuel system/computer limits...I'm just shooting to flatten out the torque curve of my 302, and make good power down at 2 grand. I don't think i'd need new injectors, MAF, or anything, and at higher RPM's a lot of exhaust would be going through the wastegate
The goal here is simplicity, fuel economy, driveability, and torque. Because the total air at high RPM won't be much more than stock (say 2 psi of boost) the air coming through the MAF (draw-through) won't be too much for the computer to handle. It will just have the ability to suck that much air at any rpm.
Things i'd need to do
-Small turbo after the Y pipe, before the cat.
-Big *** wastegate pipe that bypasses the turbo
-Intercooler & Intake piping
Any thoughts?
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Really? You don't think that, if the computer can handle 500 cfm of air flowing through the MAF at 5000 rpm, it can inject the same amount of fuel at 2000 rpm?
I dunno, my dad put a blower on his crown vic with no tuning. it ran a little lean at high rpm but 0-3000 it ran great. slightly bigger injectors fixed almost everything.
I dunno, my dad put a blower on his crown vic with no tuning. it ran a little lean at high rpm but 0-3000 it ran great. slightly bigger injectors fixed almost everything.
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I think you are misunderstanding me...
The stock fuel system can handle the 5.0 no boost, at 5,000 RPM. That means that you should be able to run
32 psi at 1500
14 psi at 2500
9 psi at 3500
1.5 psi at 4500
without exceeding the stock fuel system capabilities (measuring air drawn through the MAF and deliver X amount of fuel). Even at closed loop, the computer still references the MAF and the IAT.
Also, rate of air consumption is directly related to horsepower.
So, if these engines make 200 hp at 4 grand, with 14 psi boost I should be able to make 200 hp at 2 grand.
200 hp at 2000 rpm = 525 ft-lb of torque
Lets just say I shoot for a boost curve of 9 psi up to 3500, and then i let the boost tail off (turbo is maxed out, cannot flow any more through the turbine ,wastegate opens) to 0 psi at 5k. I expect it would generate ~ 420 ftlb of torque at 2k.
Which would be sweet.
The stock fuel system can handle the 5.0 no boost, at 5,000 RPM. That means that you should be able to run
32 psi at 1500
14 psi at 2500
9 psi at 3500
1.5 psi at 4500
without exceeding the stock fuel system capabilities (measuring air drawn through the MAF and deliver X amount of fuel). Even at closed loop, the computer still references the MAF and the IAT.
Also, rate of air consumption is directly related to horsepower.
So, if these engines make 200 hp at 4 grand, with 14 psi boost I should be able to make 200 hp at 2 grand.
200 hp at 2000 rpm = 525 ft-lb of torque
Lets just say I shoot for a boost curve of 9 psi up to 3500, and then i let the boost tail off (turbo is maxed out, cannot flow any more through the turbine ,wastegate opens) to 0 psi at 5k. I expect it would generate ~ 420 ftlb of torque at 2k.
Which would be sweet.
Lead Driver
Joined: Jul 2007
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From: Rhode Island
It might work in theory, but you'd need a fancy turbo management system that is for sure.
If you reach the point where you cannot flow any more exhaust through the turbine, then you are choking your engine - quite severally. Wastegates also function based on the intake side of pressure, not the exhaust side. Mechanical wastegates have one set pressure. So if you set it to say 9 PSI, the wastegate doesn't know the difference between 2000 or 5000 RPM, so its going to try and maintain that 9 PSI all the way till the engine maxes out in revs. To do what you want it to do, you're going to need an external electronic wastegate and a very sophisticated boost controller.
There is another issue to, 420-500 lb-ft will be severally stressing the stock internals of a 5.0, enough to the point where I doubt you reliability will be good at all. I also think 9-12 PSI would be also be pushing what the stock headgasket can hold.
IMO, you should either go with a low boost (5-7 PSI) conventional turbo setup and get bigger injectors + tune, or just do the basics like long tube headers, cam, and tune it to run a bit more timing at the lower RPMs.
If you reach the point where you cannot flow any more exhaust through the turbine, then you are choking your engine - quite severally. Wastegates also function based on the intake side of pressure, not the exhaust side. Mechanical wastegates have one set pressure. So if you set it to say 9 PSI, the wastegate doesn't know the difference between 2000 or 5000 RPM, so its going to try and maintain that 9 PSI all the way till the engine maxes out in revs. To do what you want it to do, you're going to need an external electronic wastegate and a very sophisticated boost controller.
There is another issue to, 420-500 lb-ft will be severally stressing the stock internals of a 5.0, enough to the point where I doubt you reliability will be good at all. I also think 9-12 PSI would be also be pushing what the stock headgasket can hold.
IMO, you should either go with a low boost (5-7 PSI) conventional turbo setup and get bigger injectors + tune, or just do the basics like long tube headers, cam, and tune it to run a bit more timing at the lower RPMs.
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I say use two of those turbos, you don't want a small turbo. All it will do is fall flat on its face is higher rpms. I'm not to knowledgable on 5.0 turbos but you should make good power with about 5 psi. If the motor can take it I have no idea, def need larger injectors, colder plugs, and some type of way to dial it in.
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Thats exactly what I'm trying to avoid...the idea here is not to make more power..it's to make the same power at less RPM and improve efficiency all at the same time, without having to do much, if anything to the existing engine management. Obviously, the ECM doesn't control the turbo, so we need something to control that.
You really want electonic control for the turbo. That's the way it's been done since the late 80s when EFI and o2 sensors came out, for one major safety factor: if the o2 reads lean for more than a second, cut the boost. I have to do more research on electronic boost controllers, but it's not nearly as complex as fuel management ECM and you can buy a plug-and-play, fully tunable ECM for these trucks for $1500 from Jegs.
You really want electonic control for the turbo. That's the way it's been done since the late 80s when EFI and o2 sensors came out, for one major safety factor: if the o2 reads lean for more than a second, cut the boost. I have to do more research on electronic boost controllers, but it's not nearly as complex as fuel management ECM and you can buy a plug-and-play, fully tunable ECM for these trucks for $1500 from Jegs.
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I would not do it, it is an interesting idea though.
Small turbo, as said before, will choke the engine at higher rpms, would have to see the compressor map to be sure exactly where.
You could use an FMU to tune the fuel delivery but 12psi at 1500 rpms will, most surely, cause predetonation with the stock/ NA spark advance, if you retard it till no predet is found, you could en up losing power.
Again without comp map or turbo specs impossible to tell for sure.
300 hp are easy with an MP-T70 @ 5-6 psi and a little tune from the FMU and spark retard.
With an .68 ar you could be seeing boost from 2400 or 2600 rpms.
Small turbo, as said before, will choke the engine at higher rpms, would have to see the compressor map to be sure exactly where.
You could use an FMU to tune the fuel delivery but 12psi at 1500 rpms will, most surely, cause predetonation with the stock/ NA spark advance, if you retard it till no predet is found, you could en up losing power.
Again without comp map or turbo specs impossible to tell for sure.
300 hp are easy with an MP-T70 @ 5-6 psi and a little tune from the FMU and spark retard.
With an .68 ar you could be seeing boost from 2400 or 2600 rpms.
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2400 is too high for what I want to do. I want boost at 60 mph highway cruise (1900 rpm). I don't rev the truck over 3500, well, ever. And if it had more torque i'd be willing to rev even less. Already changed the cam timing - advanced 4 degrees (at the crank), and that helped out the low end a LOT. It actually feels like truck motor!
The wastegate would have to have 2 methods of actuation - #1 would obviously be intake pressure, and #2 would be back pressure between the turbo and the engine. at low rpms, the pressure in the manifolds is lower, and the boost pressure is high, while at high rpm there's more pressure in the manifolds, so the gate would open sooner. The idea is the wastegate is BIG - no chocking the motor at high rpm if I ever do feel like running up there. The ideal torque peak would be around 1800 rpm and HP around 3500, so revving it much higher isn't really necessary.
could you get the spark retard necessary by false-alarming the knock sensor input while under boost?
...does a pre-OBD II truck have a knock sensor??
The wastegate would have to have 2 methods of actuation - #1 would obviously be intake pressure, and #2 would be back pressure between the turbo and the engine. at low rpms, the pressure in the manifolds is lower, and the boost pressure is high, while at high rpm there's more pressure in the manifolds, so the gate would open sooner. The idea is the wastegate is BIG - no chocking the motor at high rpm if I ever do feel like running up there. The ideal torque peak would be around 1800 rpm and HP around 3500, so revving it much higher isn't really necessary.
could you get the spark retard necessary by false-alarming the knock sensor input while under boost?
...does a pre-OBD II truck have a knock sensor??
Posting Guru
Joined: Dec 2008
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From: Rusty, Maine
#1-If you want to boost at low R's then I would get a small diesel turbo.
#2-if you only want 2 psi boost, then you don't need an intercooler. And if you ran at 14 psi you would deffinatly need to reduce your compression ratio A LOT.
And for the rest......that's a lot of fabrication and money for a 2000 rpm range, power increase.
#2-if you only want 2 psi boost, then you don't need an intercooler. And if you ran at 14 psi you would deffinatly need to reduce your compression ratio A LOT.
And for the rest......that's a lot of fabrication and money for a 2000 rpm range, power increase.
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Oh you guys... I'm not replacing my entire engine with a turbodiesel. It's not even that much fab - a turbo, wastegate, and some intake plumbing. As long as I can figure the wastegate design out, i should be able to run a few psi at lower RPMs without doing ANYTHING to the computer. Because it's a draw-through MAF, an intercooler may be a bad idea, though some peopme make it work on mustangs.
I've been pretty busy at work, but the more I think about this the more I think it's possible. The two main hurdles are
A: choose the turbo
B: design the wastegate
What do you guys think of this way to run the wastegate : it could be a voltage-based actuator. if the MAF voltage breaks some number (4 volts ish, obviously this needs tuned) it starts bleeding boost.
And, I dunno, for a couple hundred dollars I expect at least 50 ft*lb of torque. Even if it only boost power from 1500 to 3500 rpm, how often do you run the engine outside of that? I never do.
I've been pretty busy at work, but the more I think about this the more I think it's possible. The two main hurdles are
A: choose the turbo
B: design the wastegate
What do you guys think of this way to run the wastegate : it could be a voltage-based actuator. if the MAF voltage breaks some number (4 volts ish, obviously this needs tuned) it starts bleeding boost.
And, I dunno, for a couple hundred dollars I expect at least 50 ft*lb of torque. Even if it only boost power from 1500 to 3500 rpm, how often do you run the engine outside of that? I never do.
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Well if you want to do it cheap, and I am sure I will get crap for doing this get your electric turbo, mod your intake and some better plugs and wires, and exhaust. But if you are wanting to use 2.3L 1 turbo isn't big enough to add to a 5L. Unless your going to use 2 of those turbos and twin turbo your 5L. here is a list of stuff with turbo's you should look into as well.
Intercooler
exhaust manifold plus exhaust
map sensor
blow off valve
wastegate
booster
vacuum/manual boost adjusters
intake mod
oil supply external supply pump
fixing for the turbo
turbo its self
If you are sure you want to do this.
They was some one on ebay selling kits for turbo out engines. Which comes with almost every thing but the exhaust for these. It was under a $1000.00 for a Stage one.
Intercooler
exhaust manifold plus exhaust
map sensor
blow off valve
wastegate
booster
vacuum/manual boost adjusters
intake mod
oil supply external supply pump
fixing for the turbo
turbo its self
If you are sure you want to do this.
They was some one on ebay selling kits for turbo out engines. Which comes with almost every thing but the exhaust for these. It was under a $1000.00 for a Stage one.
Posting Guru
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From: Quesnel, BC, Canada
I understand your frustration here. People arent seeing the fact that you want to shift your powerband to lower RPM. You gave an example of a 2.3L turbo because the engine is approximately half the size of the 5.0L, but the turbo for the 2.3L is designed to operate with the engine rpm up to about 6000rpm (stock). So your logic is: you have twice the engine (5.0L vs 2.3L) but only wish to operate approx half the RPM as the 2.3 (3500 vs 6000)...
-so IN THEORY: (2 x engine) + (0.5 x rpm)= Comparable approximate airlfow (CFM)
You could try to use a rev limiter set to ~3750 rpm to keep from overspeeding the turbo and all other potential catastrophic failure that could follow.
or as someone mentioned, an electronic BOV...you could use a voltage sensor so when the signal from the maf reaches a certain voltage it pops the BOV open..This sounds more complex tho because you would have to set the "close" voltage lower than the "open" voltage so you dont end up bouncing/fluttering the BOV open and closed.
I like the RPM limiter best, simple and guaranteed protection.
-so IN THEORY: (2 x engine) + (0.5 x rpm)= Comparable approximate airlfow (CFM)
You could try to use a rev limiter set to ~3750 rpm to keep from overspeeding the turbo and all other potential catastrophic failure that could follow.
or as someone mentioned, an electronic BOV...you could use a voltage sensor so when the signal from the maf reaches a certain voltage it pops the BOV open..This sounds more complex tho because you would have to set the "close" voltage lower than the "open" voltage so you dont end up bouncing/fluttering the BOV open and closed.
I like the RPM limiter best, simple and guaranteed protection.