GM HighTech Writeup on Procharger/Wastegate setups
#42
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Lol why is this such a heated debate with you alchemist? Ok so my d1 has 3.4 pulley and 7.65 crank pulley I have it making 11psi at "peak" it carries 10-11lbs from 4000rpm to redline. I have stock bottom end. So alchemist should I take off the wastegate and run it without it because its already making all that boost at max tq? Lol I love the extra tq I now have. Feels much better than it did without it.
So I guess do I just run the 3.4" pulley and make whatever boost up top? I always thought it was the boost that hurt motors but the comment about cylinder pressure and torques makes sense too. I also only have a 2 bar so I was going to limit the boost to the 14-15 psi.
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We've tossed around trying this on our '95 Formula, it would be interesting to see how much faster it would run in the 1/4. Bob
We've tossed around trying this on our '95 Formula, it would be interesting to see how much faster it would run in the 1/4. Bob
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#44
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makes complete sense to me.
all it really is doing, is forcing the blower to spin faster sooner w the smaller head unit pulley.but the wg controls the amount of airflow the motor ingests at a given time.
the blower does not care, its pumpin all the air its being asked to. if the wg was not present, controlling the airflow, it would ingest the whole amount of air coming in.
basically blower is being forced to spin quicker w small pulley, therefore bringin it up to its sweet spot faster. wg only allows the desired amt of boost the driver wishes. without having to worry about engine damage, or at least reduce the possibility of overboost damage. pretty neat trick
all it really is doing, is forcing the blower to spin faster sooner w the smaller head unit pulley.but the wg controls the amount of airflow the motor ingests at a given time.
the blower does not care, its pumpin all the air its being asked to. if the wg was not present, controlling the airflow, it would ingest the whole amount of air coming in.
basically blower is being forced to spin quicker w small pulley, therefore bringin it up to its sweet spot faster. wg only allows the desired amt of boost the driver wishes. without having to worry about engine damage, or at least reduce the possibility of overboost damage. pretty neat trick
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#45
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1. You LOVE snacky cakes!
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
2. You'll eat as many snacky cakes as you're given, but you can only eat 8 snacky cakes at a time, or you'll die.
![Bomb](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_bomb.gif)
3. You love to eat snacky cakes anytime from 1-6pm, and you gobble them all up as soon as you get them.
4. Even though you could start eating snacky cakes at 1pm, your mom doesn't even start giving them to you until 2pm.
![Sad](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_sad.gif)
5. But, at 2pm, she only gives you 1 measly snacky cake.
6. Then, at 3pm, she gives you 2 snacky cakes.
7. At 4pm, she gives you 3 snacky cakes.
8. At 5pm, she gives you 6 snacky cakes...starting to get generous!
9. Finally, at 6pm, wouldn't you know it...just when you're almost done eating for the day, she gives you your maximum limit of 8 snacky cakes!
Now...with all the above being said, wouldn't you like it MUCH BETTER if:
1. Your mom started giving you more snacky cakes sooner.
2. She started giving you your max amount of 8 snacky cakes at 4pm, AND she KEPT giving you 8 more every hour all the way thru 6pm?
Just in case you still don't follow...
![Secret](https://ls1tech.com/forums/images/smilies3/secret2.gif)
Equation:
"You" = The Engine
"Mom" = Blower
"Snacky Cakes" = Boost
"Hour" = RPMx1000
"Done Eating For The Day" = Redline
Bazzzinga!
Last edited by ss2000silverbullet; 07-10-2013 at 12:03 AM. Reason: Making sure I was explaining myself. Lol
#46
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Lets simplify things with a story from our 4th grade economics book...
1. You LOVE snacky cakes!![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
2. You'll eat as many snacky cakes as you're given, but you can only eat 8 snacky cakes at a time, or you'll die.![Bomb](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_bomb.gif)
3. You love to eat snacky cakes anytime from 1-6pm, and you gobble them all up as soon as you get them.
4. Now, even though you could start eating snacky cakes at 1pm, your mom doesn't even start giving them to you until around 2.
5. At 2pm, she only gives you 1 measly snacky cake.
6. But, at 4pm, she gives you 3 snacky cakes.
7. Then, at 5pm, she gives you 6 snacky cakes.
8. Finally, at 6pm, wouldn't you know it...just when you're almost done eating for the day, she gives you your maximum limit of 8 snacky cakes!
Now...with all the above being said, wouldn't you like it MUCH BETTER if your mom started giving you your full 8 snacky cakes limit at 4pm, AND kept giving you 8 more every hour all the way thru 6pm?
Just in case you still don't follow...![Secret](https://ls1tech.com/forums/images/smilies3/secret2.gif)
Equation:
"You" = The Engine
"Mom" = Blower
"Snacky Cakes" = Boost
"Hour" = RPMx1000
"Done Eating For The Day" = Redline
Bazzzinga!
1. You LOVE snacky cakes!
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
2. You'll eat as many snacky cakes as you're given, but you can only eat 8 snacky cakes at a time, or you'll die.
![Bomb](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_bomb.gif)
3. You love to eat snacky cakes anytime from 1-6pm, and you gobble them all up as soon as you get them.
4. Now, even though you could start eating snacky cakes at 1pm, your mom doesn't even start giving them to you until around 2.
5. At 2pm, she only gives you 1 measly snacky cake.
6. But, at 4pm, she gives you 3 snacky cakes.
7. Then, at 5pm, she gives you 6 snacky cakes.
8. Finally, at 6pm, wouldn't you know it...just when you're almost done eating for the day, she gives you your maximum limit of 8 snacky cakes!
Now...with all the above being said, wouldn't you like it MUCH BETTER if your mom started giving you your full 8 snacky cakes limit at 4pm, AND kept giving you 8 more every hour all the way thru 6pm?
Just in case you still don't follow...
![Secret](https://ls1tech.com/forums/images/smilies3/secret2.gif)
Equation:
"You" = The Engine
"Mom" = Blower
"Snacky Cakes" = Boost
"Hour" = RPMx1000
"Done Eating For The Day" = Redline
Bazzzinga!
#48
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All I'm going to say is, you're not going to hurt your motor anymore by pushing more boost past the point of peak torque because the few extra psi of boost is nothing in comparison to the amount of cylinder pressure generated at the peak torque range.
No one has yet to explain why we can lean out a motor, and add more timing once we get past that rpm range, but we can't add more airflow because it's somehow not safe. That's the point I'm making. You don't need massive amounts of torque at 1500-3500 rpm because you have gears to get you above that rpm quickly. You want the max amount of torque from whatever rpm your motor sees after it shifts up to the next shift rpm. At least you do if you want to go faster.
Again, if I'm wrong, please tell me where I'm wrong. And the 4th grade cupcake crap is just childish. I'm trying to have an intellectual discussion about this, not trying to **** people off or get childish.
Fact is, noone has said why if it's safe to run for example 12psi of boost at 5000rpm, why it's unsafe to run 15psi of boost at 6000rpm. Cylinder pressures are lower at that point, which ultimately is what damages things.
Do what you want guys. Chose your own path.
No one has yet to explain why we can lean out a motor, and add more timing once we get past that rpm range, but we can't add more airflow because it's somehow not safe. That's the point I'm making. You don't need massive amounts of torque at 1500-3500 rpm because you have gears to get you above that rpm quickly. You want the max amount of torque from whatever rpm your motor sees after it shifts up to the next shift rpm. At least you do if you want to go faster.
Again, if I'm wrong, please tell me where I'm wrong. And the 4th grade cupcake crap is just childish. I'm trying to have an intellectual discussion about this, not trying to **** people off or get childish.
Fact is, noone has said why if it's safe to run for example 12psi of boost at 5000rpm, why it's unsafe to run 15psi of boost at 6000rpm. Cylinder pressures are lower at that point, which ultimately is what damages things.
Do what you want guys. Chose your own path.
#49
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iTrader: (19)
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Lets simplify things with a story from our 4th grade economics book...
1. You LOVE snacky cakes!![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
2. You'll eat as many snacky cakes as you're given, but you can only eat 8 snacky cakes at a time, or you'll die.![Bomb](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_bomb.gif)
3. You love to eat snacky cakes anytime from 1-6pm, and you gobble them all up as soon as you get them.
4. Even though you could start eating snacky cakes at 1pm, your mom doesn't even start giving them to you until 2pm.
5. But, at 2pm, she only gives you 1 measly snacky cake.
6. Then, at 3pm, she gives you 2 snacky cakes.
7. At 4pm, she gives you 3 snacky cakes.
8. At 5pm, she gives you 6 snacky cakes...starting to get generous!
9. Finally, at 6pm, wouldn't you know it...just when you're almost done eating for the day, she gives you your maximum limit of 8 snacky cakes!
Now...with all the above being said, wouldn't you like it MUCH BETTER if:
1. Your mom started giving you more snacky cakes sooner.
2. She started giving you your max amount of 8 snacky cakes at 4pm, AND she KEPT giving you 8 more every hour all the way thru 6pm?
Just in case you still don't follow...![Secret](https://ls1tech.com/forums/images/smilies3/secret2.gif)
Equation:
"You" = The Engine
"Mom" = Blower
"Snacky Cakes" = Boost
"Hour" = RPMx1000
"Done Eating For The Day" = Redline
Bazzzinga!
1. You LOVE snacky cakes!
![Happy](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_stretch.gif)
2. You'll eat as many snacky cakes as you're given, but you can only eat 8 snacky cakes at a time, or you'll die.
![Bomb](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_bomb.gif)
3. You love to eat snacky cakes anytime from 1-6pm, and you gobble them all up as soon as you get them.
4. Even though you could start eating snacky cakes at 1pm, your mom doesn't even start giving them to you until 2pm.
![Sad](https://ls1tech.com/forums/images/smilies/LS1Tech/gr_sad.gif)
5. But, at 2pm, she only gives you 1 measly snacky cake.
6. Then, at 3pm, she gives you 2 snacky cakes.
7. At 4pm, she gives you 3 snacky cakes.
8. At 5pm, she gives you 6 snacky cakes...starting to get generous!
9. Finally, at 6pm, wouldn't you know it...just when you're almost done eating for the day, she gives you your maximum limit of 8 snacky cakes!
Now...with all the above being said, wouldn't you like it MUCH BETTER if:
1. Your mom started giving you more snacky cakes sooner.
2. She started giving you your max amount of 8 snacky cakes at 4pm, AND she KEPT giving you 8 more every hour all the way thru 6pm?
Just in case you still don't follow...
![Secret](https://ls1tech.com/forums/images/smilies3/secret2.gif)
Equation:
"You" = The Engine
"Mom" = Blower
"Snacky Cakes" = Boost
"Hour" = RPMx1000
"Done Eating For The Day" = Redline
Bazzzinga!
#50
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But you CAN'T tell your blower, "Hey pal, why don't ya spool me up another 3psi at the end of my torque curve."
But with a wastegate application you CAN make it bring on power sooner, give you all it's got sooner, KEEP IT AT THAT POINT TIL REDLINE, and avoid blowing your engine sky high.
Like you said, do what you want...
Personally, I'm going with the wastegate/boost limiting valve option so I don't have to run my engine to redline everytime I want to see what I paid for.
But with a wastegate application you CAN make it bring on power sooner, give you all it's got sooner, KEEP IT AT THAT POINT TIL REDLINE, and avoid blowing your engine sky high.
Like you said, do what you want...
Personally, I'm going with the wastegate/boost limiting valve option so I don't have to run my engine to redline everytime I want to see what I paid for.
#52
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All I'm going to say is, you're not going to hurt your motor anymore by pushing more boost past the point of peak torque because the few extra psi of boost is nothing in comparison to the amount of cylinder pressure generated at the peak torque range.
No one has yet to explain why we can lean out a motor, and add more timing once we get past that rpm range, but we can't add more airflow because it's somehow not safe. That's the point I'm making. You don't need massive amounts of torque at 1500-3500 rpm because you have gears to get you above that rpm quickly. You want the max amount of torque from whatever rpm your motor sees after it shifts up to the next shift rpm. At least you do if you want to go faster.
No one has yet to explain why we can lean out a motor, and add more timing once we get past that rpm range, but we can't add more airflow because it's somehow not safe. That's the point I'm making. You don't need massive amounts of torque at 1500-3500 rpm because you have gears to get you above that rpm quickly. You want the max amount of torque from whatever rpm your motor sees after it shifts up to the next shift rpm. At least you do if you want to go faster.
Say someone wants 500hp and thats it. He has to spin his car to 6000rpm just to get ~8psi and 500hp and at peak torque he made 6psi. He then puts a smaller pulley on and adds a wastegate. Now he still should make 500hp if he sets the wastegate to 8psi but he should pick up torque because the blower is spinning faster and he might already be at 8psi at peak torque. Now this is where your arguement starts.. why not just let it keep making boost and thus more power? I agree..BUT
The wastegate is for those people who put a much a smaller pulley and risk making too much boost at peak torque. With the smallest pulley they might be at 12lbs at peak torque and 15lbs by redline but the motor might not be able to handle the torque created at 12lbs.. They wastegate it and keep it well below but still benefit from faster spinning blower.
I still agree that if you have a setup that can handle the torque put the smaller pulley on and do not put a wastegate on it. But if you run the smallest pulley you can and your setup cannot handle torque it will create when unregulated, then put a wastegate on it (or build a motor and skip the gate lol)
IIRC you were making about 15psi when your motor let go. If you would have pulley'd down and set the gate to 15psi you would have made more power at peak torque then you did before and possibly blown up sooner due to the increased power under the curve. Pulleying down without the wastegate wouldve had essentially the same effect (but with more boost/pwer at redline) so i can see where your arguement comes from. Its really for people who want use a smaller pulley but cant because the motor cant handle it and just use the wastegate as means of bringing on the power sooner.
Last edited by Ryans99ls1; 07-10-2013 at 11:56 AM.
#53
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Ryan, you're spot-on with your analysis, but I don't think that was "Alchemist's" argument...
Nobody on here has said that IF your engine CAN handle the full range of boost created from being pullied-down that it should be bled off with a wastegate.
He's under the impression that if you achieve your max boost earlier in your revs that your torque curve will fall out earlier. (Even though you'd be maintaining the full usable boost the rest of the way up the revs to redline.)
Nobody on here has said that IF your engine CAN handle the full range of boost created from being pullied-down that it should be bled off with a wastegate.
He's under the impression that if you achieve your max boost earlier in your revs that your torque curve will fall out earlier. (Even though you'd be maintaining the full usable boost the rest of the way up the revs to redline.)
Last edited by ss2000silverbullet; 07-10-2013 at 12:07 PM.
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I know I'm putting a little more stress on being waste gated and pullied all the way down. But I don't see tq under the curve being that much higher than I was on 150shot so I'm cool with doing it. To each his own.
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its no different than a turbo reaching full boost at 2500rpm and the wastegate limiting the boost all the way through the rpm range to redline. they make better power/torque under the curve than a centri. wategating a centri makes it "spool," if u will, more like a turbo ie bringing the boost in faster giving you more power and torque through the midrange where centris lack.
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#57
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Alchemist is missing it slightly.
By his reasoning, everyone should just pulley their setup for maximum power at all times. Clearly that wont work for everyone though. That can be for many reasons. the engine might not take it, fuel system, drivetrain etc etc.
All most people are trying to do when they apply this, is increase power/torque in the lower rpm range. This is done by spinning the blower much faster than would normally be the case. But in order to limit power/torque at the upper rpm's when boost would normally climb, instead they choose to dump that air. It should provide a less linear power increase, and instead a flatter power/torque curve.
The other option is to use venting the air as a means of power reduction at lower speeds/gears to assist with traction, then at higher speeds revert back to full power again by closing any valves.
But for a proper drag strip scenario where there is always great traction if using suitable tyres....just run maximum power at all times.
Airfield, street or other low traction venue, then you can apply a power reduction by limiting boost.
By his reasoning, everyone should just pulley their setup for maximum power at all times. Clearly that wont work for everyone though. That can be for many reasons. the engine might not take it, fuel system, drivetrain etc etc.
All most people are trying to do when they apply this, is increase power/torque in the lower rpm range. This is done by spinning the blower much faster than would normally be the case. But in order to limit power/torque at the upper rpm's when boost would normally climb, instead they choose to dump that air. It should provide a less linear power increase, and instead a flatter power/torque curve.
The other option is to use venting the air as a means of power reduction at lower speeds/gears to assist with traction, then at higher speeds revert back to full power again by closing any valves.
But for a proper drag strip scenario where there is always great traction if using suitable tyres....just run maximum power at all times.
Airfield, street or other low traction venue, then you can apply a power reduction by limiting boost.
#58
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Guys, I think you're not understanding what I'm saying. I'm not saying everyone should just pulley down and get max boost.... what I'm saying is, max horspower doesn't necessarily kill a motor, but max torque.
I'm saying that if you put in a 15psi wastegate, which opens at let's say 5500 rpm, I don't think you're any safer than if you let the boost build past that point to 18, 19psi at redline.
I guess the key here is deciding where to limit the boost, rpm wise, is more critical than the actual boost pressure. All I was trying to say was, if the motor is fine running x amount of boost at your torque peak, then you should be fine letting the boost continue to rise after that. But it sounds like you guys are talking about putting on a tiny pulley, and opening the wastegate at like 3000-4000rpm to redline. My question there is how much of an impact on the blower longevity will that create?
Again, I'm not arguing with people, just trying to get where the benefit of this is. I would think that it would put a lot of stress on the blower to spin it like that.
I'm saying that if you put in a 15psi wastegate, which opens at let's say 5500 rpm, I don't think you're any safer than if you let the boost build past that point to 18, 19psi at redline.
I guess the key here is deciding where to limit the boost, rpm wise, is more critical than the actual boost pressure. All I was trying to say was, if the motor is fine running x amount of boost at your torque peak, then you should be fine letting the boost continue to rise after that. But it sounds like you guys are talking about putting on a tiny pulley, and opening the wastegate at like 3000-4000rpm to redline. My question there is how much of an impact on the blower longevity will that create?
Again, I'm not arguing with people, just trying to get where the benefit of this is. I would think that it would put a lot of stress on the blower to spin it like that.
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Guys, I think you're not understanding what I'm saying. I'm not saying everyone should just pulley down and get max boost.... what I'm saying is, max horspower doesn't necessarily kill a motor, but max torque.
I'm saying that if you put in a 15psi wastegate, which opens at let's say 5500 rpm, I don't think you're any safer than if you let the boost build past that point to 18, 19psi at redline.
I guess the key here is deciding where to limit the boost, rpm wise, is more critical than the actual boost pressure. All I was trying to say was, if the motor is fine running x amount of boost at your torque peak, then you should be fine letting the boost continue to rise after that. But it sounds like you guys are talking about putting on a tiny pulley, and opening the wastegate at like 3000-4000rpm to redline. My question there is how much of an impact on the blower longevity will that create?
Again, I'm not arguing with people, just trying to get where the benefit of this is. I would think that it would put a lot of stress on the blower to spin it like that.
I'm saying that if you put in a 15psi wastegate, which opens at let's say 5500 rpm, I don't think you're any safer than if you let the boost build past that point to 18, 19psi at redline.
I guess the key here is deciding where to limit the boost, rpm wise, is more critical than the actual boost pressure. All I was trying to say was, if the motor is fine running x amount of boost at your torque peak, then you should be fine letting the boost continue to rise after that. But it sounds like you guys are talking about putting on a tiny pulley, and opening the wastegate at like 3000-4000rpm to redline. My question there is how much of an impact on the blower longevity will that create?
Again, I'm not arguing with people, just trying to get where the benefit of this is. I would think that it would put a lot of stress on the blower to spin it like that.
If you were to add a wastegate and not change pullies, then your thoughts are exactly right. When you add a wastegate, you almost HAVE to put a smaller pulley to get any sort of benefit from it and stay within your desired limits
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Guys, I think you're not understanding what I'm saying. I'm not saying everyone should just pulley down and get max boost.... what I'm saying is, max horspower doesn't necessarily kill a motor, but max torque.
I'm saying that if you put in a 15psi wastegate, which opens at let's say 5500 rpm, I don't think you're any safer than if you let the boost build past that point to 18, 19psi at redline.
I guess the key here is deciding where to limit the boost, rpm wise, is more critical than the actual boost pressure. All I was trying to say was, if the motor is fine running x amount of boost at your torque peak, then you should be fine letting the boost continue to rise after that. But it sounds like you guys are talking about putting on a tiny pulley, and opening the wastegate at like 3000-4000rpm to redline. My question there is how much of an impact on the blower longevity will that create?
Again, I'm not arguing with people, just trying to get where the benefit of this is. I would think that it would put a lot of stress on the blower to spin it like that.
I'm saying that if you put in a 15psi wastegate, which opens at let's say 5500 rpm, I don't think you're any safer than if you let the boost build past that point to 18, 19psi at redline.
I guess the key here is deciding where to limit the boost, rpm wise, is more critical than the actual boost pressure. All I was trying to say was, if the motor is fine running x amount of boost at your torque peak, then you should be fine letting the boost continue to rise after that. But it sounds like you guys are talking about putting on a tiny pulley, and opening the wastegate at like 3000-4000rpm to redline. My question there is how much of an impact on the blower longevity will that create?
Again, I'm not arguing with people, just trying to get where the benefit of this is. I would think that it would put a lot of stress on the blower to spin it like that.
Your concerns about blower longevity are valid, but only if you pulley down so far that your impeller speed gets to the limits. As long as the formula still works out
(Crank Pulley Diameter divided by Blower Pulley Dia X Step-Up Ratio X Engine RPM Redline)
to be under the threshold of the blower's max rpm, all will be well.