Boost Bypass Mod?
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1,116 Posts
i did it and i think it is bad for the car and i would never do it again.
just my thought tho
just my thought tho
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I don't think that anyone ever decided as a group if it works or not. Here is the facts that I've seen. At 6,000 Rpms, the blower is making 12psi and on the way up some, but from 6,000 to redline the boost is bled off to 'protect' the engine. I quote 'protect' because MOST people don't think there is anything wrong with the boost building until redline since the engine is built well. There has been one dyno chart that I've ever seen with the mod done, and not done. I don't remember who's car it was, but it was WAY under the stock/common horsepower numbers that I've seen for the car. Something like 170ish without, and 180ish with? I've never seen another dyno with the mod hooked and unhooked yet, and the whole topic just dropped right off the face of the earth. There was also speculation that the computer is controling the boost in more than one way, so that unhooking the boost solenoid would force the car to use the other method available to limit boost. Which results in the same end result. IF the car can make boost over 12psi with the line unhooked, is should make some more horsepower, but only from 6000-6450. The car can only measure 14.7 psi of boost, so if you were to get the boost up over that level with the bypass done, you could be on the verge of damaging the car since the engine can no longer read what boost is to adjust the fuel, etc.
I haven't done the mod because I don't think that it works after everything that I've read and heard here. In all honesty, I never thought it would work, but that's me. I always feel if something is that easy, then it would be done to begin with. It seems that the could have just as easily started bleeding boost at 6,400 rpms instead of 6,000 if everthing would work out the same AND give more horsepower. I know car companies do strange things sometimes, but leaving 10 free horsepower in the engine dosen't make any sense to me, and I'm sure the engineers know more than I do about it.
I haven't done the mod because I don't think that it works after everything that I've read and heard here. In all honesty, I never thought it would work, but that's me. I always feel if something is that easy, then it would be done to begin with. It seems that the could have just as easily started bleeding boost at 6,400 rpms instead of 6,000 if everthing would work out the same AND give more horsepower. I know car companies do strange things sometimes, but leaving 10 free horsepower in the engine dosen't make any sense to me, and I'm sure the engineers know more than I do about it.
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69 Posts
I tried it for a day, and thought I noticed a difference, but it's really too subjective to tell. I did think, however, that we hit 12 psi at 4500 RPM's and that the boost level was held at 12 from that point on. If the mod works, then it is definately horrible for your gas milage. Eaton engineered their 4th Gen superchargers with that boost bypass drastically increasing the SC's effeciency.
http://www.magnusonproducts.com/bypass.htm
I believe Psi-Fi also confirmed that eliminating the bypass allows you to build up to 15 psi, but our fuel injectors aren't large enough to handle all that air, and the engine runs too lean.
http://www.magnusonproducts.com/bypass.htm
I believe Psi-Fi also confirmed that eliminating the bypass allows you to build up to 15 psi, but our fuel injectors aren't large enough to handle all that air, and the engine runs too lean.
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55 Posts
I did dyno the car with and without the bypass mod. Without, I got 216.8HP & 211.4HP. Immediately after the 2nd run I did the mod and got 212.3HP.
Check here for the thread: http://www.redlineforums.com/forums/showthread.php?t=842
Check here for the thread: http://www.redlineforums.com/forums/showthread.php?t=842
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22,045 Posts
No, it's to get more boost. If you want to get boost faster, then you have to spin the supercharger faster, sooner. Period. The concept is to blind the computer to the 12psi limit, thereby letting the boost climb all the way to redline. The supercharger boost is directly related to the speed of the supercharger, the only way to change the speed of the supercharger is raise the rpms of the engine, or change the pulley. If you change the pulley on it, you would get into boost faster, without making more, because of the boost control solenoid.
I'm not sure how you guys do it to get boost sooner on your GP's, but regardless that's not what people were thinking here. Even if you get into boost faster, you're doing it to get more horsepower, since the power of the engine will be made sooner and stronger than it was before.
I'm not sure how you guys do it to get boost sooner on your GP's, but regardless that's not what people were thinking here. Even if you get into boost faster, you're doing it to get more horsepower, since the power of the engine will be made sooner and stronger than it was before.
Is the way yall are doing the mod the same as this one?Sp00ner said:
Grand Prix boost bypass mod
And as a lil FYI, the SC doesnt determine where max hp is made, the cam does. Therefore, as on the GP's, MAX HP is made at 5600rpms w/ the stock cam, however max torque is down around 3500.
Check out these dyno sheets:
http://www.mccgp.com/images/members/Dyno_JBagley01.jpg
http://www.mccgp.com/images/members/Dyno_JBagley02.jpg
I just did a search, and found this:
http://www.redlineforums.com/forums/archive/index.php/t-228.html
Seems that its pretty much the same mod.
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No, not at all.
Listen to what we're saying.
With all variables the same, other than the amount of boost pushed through the system, what is that doing? Changing the amount of boost, is directy related the the amont of horsepower that you're making, yes the cams are part of it too, it all works together. In a forced induction engine, the supercharger has much more to do with the power curve than the cams do, when the supercharger is making good boost. It's no small coincidence that the power curve follows the boost curve of our cars so accurately. I'm not implying that the cams are useless, by any means. If you lower the ENTIRE boost range down, and increase the peak boost, what do you think is going to happen? You're going to gain power, both sooner and in total, that's the whole reason people change pulleys, and BOV's, and turbo wastegates, and boost controllers, and all that jazz, is to get boost faster and higher than stock. The amount of air entering your engine is what determines how much power your car makes, the cams open and close the valves at the right time, and the supercharger stuffs air through them. It's a relationship. We're ONLY talking about supercharger boost levels here.
The mod that people were talking about is to stop the supercharger from reducing boost near redline, which would increase peak boost and horsepower without changing the speed of the supercharger. ONLY because the supercharger is spinning fast enough the make more boost to begin with, and the computer for the car is bleeding it off 'for no good reason'. I don't know anything about how it work in a GP, like I said, but it's not the same thing that you're talking about.
Listen to what we're saying.
With all variables the same, other than the amount of boost pushed through the system, what is that doing? Changing the amount of boost, is directy related the the amont of horsepower that you're making, yes the cams are part of it too, it all works together. In a forced induction engine, the supercharger has much more to do with the power curve than the cams do, when the supercharger is making good boost. It's no small coincidence that the power curve follows the boost curve of our cars so accurately. I'm not implying that the cams are useless, by any means. If you lower the ENTIRE boost range down, and increase the peak boost, what do you think is going to happen? You're going to gain power, both sooner and in total, that's the whole reason people change pulleys, and BOV's, and turbo wastegates, and boost controllers, and all that jazz, is to get boost faster and higher than stock. The amount of air entering your engine is what determines how much power your car makes, the cams open and close the valves at the right time, and the supercharger stuffs air through them. It's a relationship. We're ONLY talking about supercharger boost levels here.
The mod that people were talking about is to stop the supercharger from reducing boost near redline, which would increase peak boost and horsepower without changing the speed of the supercharger. ONLY because the supercharger is spinning fast enough the make more boost to begin with, and the computer for the car is bleeding it off 'for no good reason'. I don't know anything about how it work in a GP, like I said, but it's not the same thing that you're talking about.
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572 Posts
i did it today (and i have the pcm update) had someone keep pushing on the throttle it feels better in the lower end and not to much difference in the top.
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I'm only here due to helping out a freind with his anemic redline. I can't help wonder why so much of a big deal made over a car that boasts so much potential would be locked down to mearly 12psi of boost. and limited injectors? come on you guys have an off the bat advantage and theres guys still with Hondas walking all over you both at the track and in the technology shoot out !!! you guys should all be planning to utilize the options available both OEM and Aftermarket instead of bitchin about what GM shoulda, coulda, woulda done.Sp00ner said:
On a personal level i think its purely B.S. how Generous motors decided to build up the EGO of a new generation of tuners only to have it fall on its face by offering No actual support...
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Undrstm8ed said:
id love to see what hondas are going to walk all over us that dont have huge engine swaps and/or forced induction with built engines. heck ive raced turbo'd civics and handed them their asses like they were a stock ex or si.
ive said nothing about what gm should have done......they've done more than what most car companies have done for the redline, and now i plan to rely on aftermarket support for the car. you cant expect all car companies to come out with a car and then offer package upon package of performance modifications. you have no idea how liable that makes them if something goes wrong with either the car or an accident due to driving fast because of those packages. yeah, it might not be gm's fault, but they still get some of the flak for it.
and ur talking to us about ego's? cmon, we or at least i am realistic about what i can beat. if u wanna talk about egos go talk to the STEREOTYPICAL srt4 guy or STEREOTYPICAL honda/acura guy. notice i said stereotypical, not everybody with those cars is like that, and i realize and recognize that.
i dont mean to bitch, and im not trying to condemn u or anything like that, just offering a rebuttal thats all. i respect ur opinion completely.
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