The official Bosch bypass thread.

**468LC** · 11-10-2002, 09:19 AM

This is the setup I use and it is dead simple and very effective.
Why the bypass?
I have already talked to at least 6 people who have had problems with off idle bucking and surging.
It seems to be most prominant with aftermarket MAF meters.
Without the bypass you could literally here the air stalling in the airfilter box area. Kind of a warbling noise.

I used a Bosch bypass valve P/N 0 280 142 108
that I picked up locally at a parts house.
Other parts needed. two 3/4"pipe to 1" barb fittings.
1' of 1"id radiator hose.
several feet of 3/16" vacuum hose.
This install had the biggest effect on drivability on the Novi1k.
It was like a new car all over again.:)

The setup on my car is without a smog pump so I don't know for sure if my setup would clear the smog plumbing or not.
I would like to get some feedback from some of you with smog to let my know if you think it would clear or not.

If you guys have any other questions feel free to ask.

**Goliath5.0** · 11-10-2002, 12:20 PM

468LC, what are the bosch bypass valves rated at in terms of capacity? 12lbs max? Please advise.

**468LC** · 11-10-2002, 01:16 PM

Originally posted by Goliath5.0
468LC, what are the bosch bypass valves rated at in terms of capacity? 12lbs max? Please advise.

I have been told by many S trim owners that it will take 15psi before it starts to leak but I have no proof of this.
LOL I'm gonna try a search on the Corral.

**Whistler** · 11-10-2002, 08:15 PM

I am still running my smog equiptment. I'll let you know how easy/difficult the install is...Prolly have it done in a week or so, I'm just waiting on my disharge tube ;) hehe

**Goliath5.0** · 11-11-2002, 11:33 AM

Well I think mine (my bosch bypass valve) is bunking out on me :(
My idle is not the same as when I had my f-150 crank pulley. Since the 8" crank pulley installation the idle has been fluctuating from 1000 rpm to 1300 rpm.

I checked the TPS and have it around 0.95, and I even toyed with adjusting it all the way to 1.00 and still noting (went back to original 0.95 setting, idles the best for me) I think I am getting compressor surge, and the bypass is crapping out on me. I will probably get an HKS or Vortech mondo blow off valve. I dunno yet.

**Jason915** · 11-11-2002, 03:38 PM

468LC where do you hook the vacume hoose to on your set up?

**dawgsgt** · 11-11-2002, 07:05 PM

468LC the stang is running great with the custom discharge tube and Bosch bypass valve. My car has stopped surging and hunting for an idle. Thanks for all your help.

**468LC** · 11-11-2002, 09:37 PM

No problem dawg.

Jason I run my vacuum line to the tree on the firewall.
I think mine is T'eed off of my Boost gauge line.

**root** · 11-12-2002, 05:14 PM

We installed a bypass valve on Chuck's car. He has all his smog stuff, fits great!

Ian

**Whistler** · 11-12-2002, 06:24 PM

That's good news for me Ian. I was hoping there weren't going to be any clearance issues with the smog hoses. I can't wait to get mine on!!

**MikeyMustang** · 11-25-2002, 06:22 AM

Bridgeville ,Pa?? I live in Monroeville,Pa ...if you need a bypass...i have a extra one i can sell you brand new...BTW ever go to Keystone Raceway?.....if so I am the one with the Green and gold foxbody with the Novi1000

Mike

http://mikeymustang.no-ip.org/

best 11.81 @122mph

**Doug** · 11-25-2002, 12:29 PM

Green and gold foxbody. HUH. Pics please

Edit. My mistake. I just seen your link, BTW I couldnt tell for sure from the pic, but is that a wing on your car?

**bileaux** · 11-25-2002, 02:00 PM

If you need to use a bypass to chamber unwanted pressure because your t/b is closed, why do you have to plumb in back into the intake tube? Can't you just let it empty into the engine bay?
New NOVI 1000 owner with lots of questions...
Thanks,
Jean

**468LC** · 11-25-2002, 02:13 PM

Originally posted by bileaux
Can't you just let it empty into the engine bay?

No
You will lose metered air that was supposed to enter the engine.

It's not impossible though, it can be done with a blow through mass air meter setup.