Electronic vs. Mechcanical boost control
08-29-2005 | 12:16 PM
#31
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From: Chicagoland,Flint MI
Thanks for all the help. It looks like I have some homework to do. Does anyone have any recomended reading on turbochargers and turbocharging systems either 951 specific or not? I'm sure that it would help me make more intelligent questions.
08-29-2005 | 02:30 PM
#32
Pro
Joined: Dec 2004
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From: Reno, NV
08-29-2005 | 02:55 PM
#33
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From: SF Bay
J_Kapp - I'm never one to discourage someone from education themselves on anything so I think it's a great idea to read up on turbo's etc.
I also think that for what it sounds like you want to do you can keep it very simple.
951's with autothority chips have been done many many times. You'll be perfectly happy with what the banjo bolt will do for you. A $50 MBC will get you even better results with the same 10 minute install.
Many people will tell you to go with this or that more complicated solution and they all have their merits. For a lot of people, an EBC is a simple thing to do. People's definition of complicated vary. But nothing is simpler than either the banjo bolt or the MBC. You don't need to run the MBC into the car. You don't need to adjust boost for conditions. You don't need electronic adjustment of timing or fuel maps.
Just install the banjo bolt or an MBC in 10 minutes. Be done with it and have an easy 30-50rwhp boost in 10 minutes and <$400. When you want more power, then we can all talk about the complexities and different paths to get there.
Autothority chips and 15psi. Be done with it.
I also think that for what it sounds like you want to do you can keep it very simple.
951's with autothority chips have been done many many times. You'll be perfectly happy with what the banjo bolt will do for you. A $50 MBC will get you even better results with the same 10 minute install.
Many people will tell you to go with this or that more complicated solution and they all have their merits. For a lot of people, an EBC is a simple thing to do. People's definition of complicated vary. But nothing is simpler than either the banjo bolt or the MBC. You don't need to run the MBC into the car. You don't need to adjust boost for conditions. You don't need electronic adjustment of timing or fuel maps.
Just install the banjo bolt or an MBC in 10 minutes. Be done with it and have an easy 30-50rwhp boost in 10 minutes and <$400. When you want more power, then we can all talk about the complexities and different paths to get there.
Autothority chips and 15psi. Be done with it.
08-29-2005 | 03:48 PM
#34
Three Wheelin'
Joined: Nov 2001
Posts: 1,594
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From: Costa Mesa, CA
Hey, are there any ways to visually identify an autothority jetted banjo bolt? Any tell-tale markings?
I supposedly have APE chips in my 951, and want to be sure my banjo bolt is either one or the other.
I supposedly have APE chips in my 951, and want to be sure my banjo bolt is either one or the other.
08-29-2005 | 04:45 PM
#36
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From: Chicagoland,Flint MI
My car has a Lindsey Boost Enhancer already on it. Correct me if I'm wrong but the boost enhancer does the same job as the banjo bolt. I think the boost enhancer completely blocks boost to the wastegate until the set limit and the banjo bolt just restricts it while still allowing some pressure to flow to the wastegate. Also what effect will the LBE have on a mechanical boost control is any?
Ninefiveone,
I deffinatly agree with you that I need to stick to the simple path, as I am cleary no expert in turbocharing. Thanks for the input.
I'll also check out that book and see what I can pick up from it.
Ninefiveone,
I deffinatly agree with you that I need to stick to the simple path, as I am cleary no expert in turbocharing. Thanks for the input.
I'll also check out that book and see what I can pick up from it.
08-29-2005 | 05:36 PM
#37
Racer
Joined: Aug 2003
Posts: 494
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From: South Florida
J_Kapp
Corky Bell is good reading. However, my suggestion is to pick a tuner and stick to him. I too had AA chips with banjo bolt then moved to reliboost and some barely functional chips (I can still kick myself for wasting hard earned money.) While there are several tuners out there, there is only one in my mind that stands above all. To me its all about customer service then performance. Do a search on Fast 951. I promise that you'll never look back (outside possibility to see how far you left the guy or if law enforcement is doing a u-turn)
My Reliboost seriously spiked in cold weather. My EBC does exactly what it is asked to do and allows for different boost levels at a touch of a button. With my EBC off I run at 12 psi. Low is set for 16 psi and high for 18. At all three levels I have somewhat acceptable A/F ratios (after almost two years of tinkering).
Happy Motoring
Corky Bell is good reading. However, my suggestion is to pick a tuner and stick to him. I too had AA chips with banjo bolt then moved to reliboost and some barely functional chips (I can still kick myself for wasting hard earned money.) While there are several tuners out there, there is only one in my mind that stands above all. To me its all about customer service then performance. Do a search on Fast 951. I promise that you'll never look back (outside possibility to see how far you left the guy or if law enforcement is doing a u-turn)
My Reliboost seriously spiked in cold weather. My EBC does exactly what it is asked to do and allows for different boost levels at a touch of a button. With my EBC off I run at 12 psi. Low is set for 16 psi and high for 18. At all three levels I have somewhat acceptable A/F ratios (after almost two years of tinkering).
Happy Motoring
08-29-2005 | 06:18 PM
#38
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From: SF Bay
The boost enhancer and the banjo bolt are working towards similar goals but different as you noted.
The problem with the boost enhancer is that it is not intended to contol boost levels but instead controls onset of boost. If you set it to 15psi, for example, it does block flow to the wastegate until 15psi and then opens. The problem is that it's not setup to do a good job of maintaining that pressure and will show spikes and an uneven level of boost. Since it's a binary device, it's either open or closed. There's no inbetween.
The banjo bolt works in conjunction with the stock cycling valve. It basically reduces the amount of pressure the cycling valve has to work with. The cycling valve is an electronic boost controller that works on a duty cycle and some other things. But to simplify, it maintains a boost level set by the ECU's. If you reduce the air pressure going to it, you get a higher boost level. Some disadvantages to it are that the ECU's try to shape the boost curve. The result is that the wastegate is opening at low boost levels and also tails off at high rpm. The benefit is that you maintain the ECU's ability to trigger limp home modes and overboost protection. For example, when you have a bad TPS, the ECU will trigger a limp home mode and reduce the amount of boost being run, regardless of what the MBC is set to. You lose that when you bypass the CV with either a MBC or EBC.
A MBC plumbed in series with the CV will do the same thing but give's you more control over what level of boost you're running.
A MBC that bypasses the CV will spool up better since the CV is no longer there to trigger early wastegate opening but you lose all the ECU limp home modes and overboost controls.
The problem with the boost enhancer is that it is not intended to contol boost levels but instead controls onset of boost. If you set it to 15psi, for example, it does block flow to the wastegate until 15psi and then opens. The problem is that it's not setup to do a good job of maintaining that pressure and will show spikes and an uneven level of boost. Since it's a binary device, it's either open or closed. There's no inbetween.
The banjo bolt works in conjunction with the stock cycling valve. It basically reduces the amount of pressure the cycling valve has to work with. The cycling valve is an electronic boost controller that works on a duty cycle and some other things. But to simplify, it maintains a boost level set by the ECU's. If you reduce the air pressure going to it, you get a higher boost level. Some disadvantages to it are that the ECU's try to shape the boost curve. The result is that the wastegate is opening at low boost levels and also tails off at high rpm. The benefit is that you maintain the ECU's ability to trigger limp home modes and overboost protection. For example, when you have a bad TPS, the ECU will trigger a limp home mode and reduce the amount of boost being run, regardless of what the MBC is set to. You lose that when you bypass the CV with either a MBC or EBC.
A MBC plumbed in series with the CV will do the same thing but give's you more control over what level of boost you're running.
A MBC that bypasses the CV will spool up better since the CV is no longer there to trigger early wastegate opening but you lose all the ECU limp home modes and overboost controls.
08-29-2005 | 07:25 PM
#39
Drifting
Joined: Feb 2003
Posts: 2,254
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From: Akron, Ohio
I can tell you that with a reli-boost (MBC) that I have NO spikes or uneven boost in my car, proven on a dyno!! It builds VERY nice to 17psi (what I had at the time) and holds it nice. My problem is that my turbo can't hold it until redline, so I have drop off to about 12psi by redline but that is due to the K26/6 turbo not the boost controller. I might upgrade to a EBC later with a new turbo so I can get lower boost in lower gears to prevent wheel spin but my reli-boost until then is good!
08-29-2005 | 08:19 PM
#41
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From: SF Bay
Yes, you shouldn't use the LBE in line with a boost controller.
However, you could use it in a manner similar to the setup DanG posted. Set the LBE to 13psi and the boost controller to 15psi. This would ensure that the wastegate is fully closed until 13psi and build more boost in the lower gears. Above that it would be completely open and the regulation of boost would be left to the boost controller as it should be.
That's all theoretical, however. Short of using the components used in the setup DanG posted, I'm not sure the LBE would work they way I'm describing.
However, you could use it in a manner similar to the setup DanG posted. Set the LBE to 13psi and the boost controller to 15psi. This would ensure that the wastegate is fully closed until 13psi and build more boost in the lower gears. Above that it would be completely open and the regulation of boost would be left to the boost controller as it should be.
That's all theoretical, however. Short of using the components used in the setup DanG posted, I'm not sure the LBE would work they way I'm describing.
08-30-2005 | 06:49 PM
#42
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Joined: Feb 2004
Posts: 6,988
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From: Los Altos, CA
Another shamless plug :-)
QUOTE=Crazy Eddie]Speaking of .... Accuboost
I have a brand new one in the bag it came in with the "ceramic upgrade ball" from the group buy last year. It's anyone's for the price I paid which was a very good deal.... It's supposed to be one of the better MBC'ss out there ...
If anyone is interested, Let me know
regards
Ed
ps I got an EBC because I have a 2 port WG and I was told it runs really good with my set up[/QUOTE]
09-23-2005 | 12:29 AM
#44
Rocket Scientist
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From: Chicago
Originally Posted by fast951
Back to basics! If the DME is programmed with the correct transfer function for the MAF used, it will know how to calculate the LOAD based on the voltage from the MAF. This is what you call "MAF chip". The DME always knows the correct LOAD, the correct air mass and will calculate the correct amount of fuel and timing needed.
If you are using a signal massager to modify the MAF signal to fake it so the DME handles it (as DME is setup for a AFM transfer function and AFM data). The DME is not calculating the correct LOAD. (the MAF voltage correlates to actual flow, but you change the voltage, so DME is getting modified values). More than likely, with this setup you will have to modify the signal with a deviation in boost. If the signal is greatly modified, you will be picking up the incorrect timing values. This appears in many forms, one of which is hesitation at part throttle.
If you are using a signal massager to modify the MAF signal to fake it so the DME handles it (as DME is setup for a AFM transfer function and AFM data). The DME is not calculating the correct LOAD. (the MAF voltage correlates to actual flow, but you change the voltage, so DME is getting modified values). More than likely, with this setup you will have to modify the signal with a deviation in boost. If the signal is greatly modified, you will be picking up the incorrect timing values. This appears in many forms, one of which is hesitation at part throttle.
09-23-2005 | 02:55 PM
#45
Pro
Joined: Jun 2005
Posts: 699
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From: New Scotland
Originally Posted by ninefiveone
-SNIP-
The banjo bolt works in conjunction with the stock cycling valve. It basically reduces the amount of pressure the cycling valve has to work with. The cycling valve is an electronic boost controller that works on a duty cycle and some other things. But to simplify, it maintains a boost level set by the ECU's. If you reduce the air pressure going to it, you get a higher boost level. Some disadvantages to it are that the ECU's try to shape the boost curve. The result is that the wastegate is opening at low boost levels and also tails off at high rpm. The benefit is that you maintain the ECU's ability to trigger limp home modes and overboost protection. For example, when you have a bad TPS, the ECU will trigger a limp home mode and reduce the amount of boost being run, regardless of what the MBC is set to. You lose that when you bypass the CV with either a MBC or EBC.
A MBC plumbed in series with the CV will do the same thing but give's you more control over what level of boost you're running.
A MBC that bypasses the CV will spool up better since the CV is no longer there to trigger early wastegate opening but you lose all the ECU limp home modes and overboost controls.
The banjo bolt works in conjunction with the stock cycling valve. It basically reduces the amount of pressure the cycling valve has to work with. The cycling valve is an electronic boost controller that works on a duty cycle and some other things. But to simplify, it maintains a boost level set by the ECU's. If you reduce the air pressure going to it, you get a higher boost level. Some disadvantages to it are that the ECU's try to shape the boost curve. The result is that the wastegate is opening at low boost levels and also tails off at high rpm. The benefit is that you maintain the ECU's ability to trigger limp home modes and overboost protection. For example, when you have a bad TPS, the ECU will trigger a limp home mode and reduce the amount of boost being run, regardless of what the MBC is set to. You lose that when you bypass the CV with either a MBC or EBC.
A MBC plumbed in series with the CV will do the same thing but give's you more control over what level of boost you're running.
A MBC that bypasses the CV will spool up better since the CV is no longer there to trigger early wastegate opening but you lose all the ECU limp home modes and overboost controls.
Questions?
I plan on slightly modifying my stock 87 951 (~66k mi). I would like to keep it as factory as possible. The main modification would be a Vitesse AFM chip running ~16psi.
1. Can I keep the stock WG? would replacing the spring be a good idea?
2. Should I just replace the WG?
3. I like the Idea of keeping the Stock CV and running a MBC in series (mbc under hood mount), is this possible with the Vitesse Software?
4. Am I out to lunch here?