I had instructed a fellow forum member not to remove his boost control as i had done it and lost both engines within a few weeks of each other. It seems that a alot of people are not running a bypass with out a problem. This has prompted me to dig deeper into this i'm welcoming any and all information, a cut away or flow lay out of an eaton would be very helpfull.
my mods include a 2.5 pully CAI catco cats and no mufflers
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85 fiero GT for sale 3800 sc goin in if it doesn't sell
94 Bonneville SSEi
93 Bonneville SSEi
94 Bonneville SSEi parts for the rest of the fleet
85 S-10 turbocharged 3800
83 Citation x-11 turbocharged 3.1 with AWD 6000 running gear SOLD

[This message has been edited by markviiisvt4 (edited 11-25-2005).]

I've had mine off for over a year, and approx 10,000 with no problems at all.

Link with some pretty good info on the removal:

Boost Bypass Removal

quote Originally posted by markviiisvt4: I had instructed a fellow forum member not to remove his boost control as i had done it and lost both engines within a few weeks of each other. It seems that a alot of people are not running a bypass with out a problem. This has prompted me to dig deeper into this i'm welcoming any and all information, a cut away or flow lay out of an eaton would be very helpfull.

I dont believe you lost your engines due to boost bypass delete. If you want to explain the whole story about your installs, maybe there can be some help here from your bad experiences. 3800SC is about the best durable engine I have come across as long as you keep KR in check. While "boost", PSI, and the worst... heat contribute to KR, a simple boost delete has not shown KR jumps to the kill zone on pistons.

ZZP tried it and bragged that it cause tooooo much wheel spin at the 60 foot. They tried to make a manual and timed control for the boost dump, but have not succeeded in that .. that I have heard of. I can in fact change the reaction of the boost dump with HP Tuners. However, everyone that has tried to "understand" what the control is, has just been more confused it seemed in forum discussions. I think if I remember correctly, DHP Powrtuner does not even have the boost controls to adjust in their tables.

And does it really "help" that much? If you are boosting at 1/4 throttle instead of dumping at this position, it is my opinion that the engine is not having to work harder to make the power to move the car at the lower speeds. There's all those physics things that I am not good at typing my explaination, but I can talk about it intelligently on the phone. Feel free to call. Then there's the gas mileage thing. Wow, you lose 1-2 MPG to more power. I will take the power.

I cant even count the cars I have deleted the thing on, and then the phone call support I have in deleting it. Number is on the website Alan provided a link to.. (PS... Thanks Alan..)

Club Grand Prix has this bigger opinion about NOT deleting it, but it comes from some guys that do the turbos. SuperChargers are tooo different in the operation to compare to turbo operations. You cannot delete the waste dump on turbos.

Loyde

i just got done talking to an eaton tec and what every one is eliminating is in essance an on off switch, it does little to control actual psi numbers. The super chargers are only capable of a certin amount of boost, the bypass valve alows the computer to relese exess boost when it's not needed for better fuel economy. However, it also acts as a safety. The computer opens the bypass when the throttle snaps shut, when it senses KR or an extreme lean condition. Wich means if somthing happens causing your car to run lean say as simple as losing a fuel Pump fuse you will lose your engine! As far as the bypass valve making the sc quiter as it says on the web site the WAY the valve is designed is what quiets the SC NOT the fact that it exisits. They do this by routing.

Now here is where my problem came in. When I removed the the bypass I did pully swaps at the same time, a tested and proven safe mod (within limits of course). Extra boost coupled with the heat created from the unused pressure having no where to go and the computer haveing no ability to dump the pressure when it sensed a lean condition poped my engine. When I asked her y it was the number one and two pistons only I was told becuse the air charge had to travel accrosse the intake it was likely that the air that was reaching the 1 and 2 cyls. was hotter .

quote Originally posted by markviiisvt4: i just got done talking to an eaton tec and what every one is eliminating is in essance an on off switch, it does little to control actual psi numbers. The super chargers are only capable of a certin amount of boost, the bypass valve alows the computer to relese exess boost when it's not needed for better fuel economy. However, it also acts as a safety. The computer opens the bypass when the throttle snaps shut, when it senses KR or an extreme lean condition. Wich means if somthing happens causing your car to run lean say as simple as losing a fuel Pump fuse you will lose your engine! As far as the bypass valve making the sc quiter as it says on the web site the WAY the valve is designed is what quiets the SC NOT the fact that it exisits. They do this by routing. Now here is where my problem came in. When I removed the the bypass I did pully swaps at the same time, a tested and proven safe mod (within limits of course). Extra boost coupled with the heat created from the unused pressure having no where to go and the computer haveing no ability to dump the pressure when it sensed a lean condition poped my engine. When I asked her y it was the number one and two pistons only I was told becuse the air charge had to travel accrosse the intake it was likely that the air that was reaching the 1 and 2 cyls. was hotter .

Well you dont mention what 'pully' change you made. You dont mention if you have IC. Changing a pulley on a supercharger is the ONE factor that relys on many variables. You made a bad decision in pulleys based on other supporting mods most likely. Boost dumping had nothing to do with it.

3.8 inch is stock.
3.4 inch is the first change most will make and the PCM can handle it fine under "most" conditions. Works in all states and temps.
3.2 inch in TEXAS, (northern states can run this some of the time) is getting to small already with no intercooler. Good PCM tuning however can make the engine live and make power.
3.0 inch in TEXAS, and many other warm states, you better have good flowing exhaust, Intercooler, and alot of custom PCM tuing.
2.8 inch, I dont care where you live, you better have excellent flow out, and intercooler, and alot of PCM tuning.

GM's code from the factory with a 3.8 inch pulley will exhibit 6 KR around Texas. Move to a 3.4 pulley, and the KR typicial stays about the 6, with some 8 spikes. PCM tuning can get this to 2 KR, and with good exhaust and tuning, the KR can be zero.

While KR = knock reduction, the real factor is denotation.

This is such a complicated topic, I dont like to type enough to make an understandable reading story. Building a 3800SC engine with mods requires alot of thought into what works with what. You put flow in, you better have flow out. People who purchased the 1.5 inch exhaust and put 3.4 pulleys on are going to be very disappointed in performance. Stock exhaust for the 3800sc has shown to be only .1 slower in quarter mile testing against 1.625 SLP headers. TOG 1.75 xtremes have shown .4 advantage. Modifications have to work together, not against each other.

If you think you killed your engine because of boost bypass delete, you might want to leave it on your next engine.

Loyde

actually 2.85 is stock (cars are 94 in my sig) i went to 2.5's CAI's on both cars catco cats and no mufflers.

Both have been back together for about a year now with out problems only thing i changed was putting back on the boost bypass. What i was told makes sense any one want to try killing their fuel pump at WOT and let me know the results?

------------------
85 fiero GT for sale 3800 sc goin in if it doesn't sell
94 Bonneville SSEi
93 Bonneville SSEi
94 Bonneville SSEi parts for the rest of the fleet
85 S-10 turbocharged 3800
83 Citation x-11 turbocharged 3.1 with AWD 6000 running gear SOLD

quote Originally posted by markviiisvt4: actually 2.85 is stock (cars are 94 in my sig) i went to 2.5's CAI's on both cars catco cats and no mufflers. Both have been back together for about a year now with out problems only thing i changed was putting back on the boost bypass. What i was told makes sense any one want to try killing their fuel pump at WOT and let me know the results?

My mistake for having this conversation with a Series I 3800SC problem. I dont support the 3800SC Series I, and I dont support OBDI.

Good luck on your future mods.

Loyde

the m90 runs almost 3 degrees cooler then the m65 i would expect it to be less of a problem. As it seems we where both talking about diffrent animals.

I would have more luck bashing my head through 2" plate steel than winning an arguement about OBD II over Loyde. . .

quote Originally posted by markviiisvt4: the m90 runs almost 3 degrees cooler then the m65 i would expect it to be less of a problem. As it seems we where both talking about diffrent animals.

I dont know much about Series I engines, but I do know the supercharger is M62, not a 65.. Even the EcoTec 2.0L has the new M62 GEN 5 supercharger. Amazing how much the GEN 5 M62 looks like the GEN 5 M90 on the 04/05 3800SC Series III.

Loyde