Boost Bypass Mod?

[BoKaThUg1]

I was just reading some threads on the Boost Bypass Mod. Does anyone still have this done, if so do u think it really makes a difference and does any one know if it is bad for the car?

[navymitch12]

i did it and i think it is bad for the car and i would never do it again.
just my thought tho

[Sp00ner]

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.

[Celticshadow]

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.

[UncleSmitty]

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: Another dyno + PCM calibration comments

[ZR2_S10]

On GTP's the boost bypass mod isnt used to make more hp, its so you get into boost faster (w/ less throttle).

[05redline]

i tried it and didnt notice a differents on the boost guage

[ZR2_S10]

Originally Posted by 05redline

i tried it and didnt notice a differents on the boost guage

Thats because it doesnt make MORE boost, it gets the car into boost faster.

[Sp00ner]

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.

[goofyguy]

well I did it and you dont get more boost or faster boost. It actually made less boost for one and it got there at the same time as always.