bypass valve install Q's

[sn95gtvert]

I installed a bypass valve on my powerdyne kit the other day. the valve acts properly only opens on rpm decel. the problem im having is it makes the engine surge. after the valve releases all the decel blower pressure my rpms drop to around 400-500 then jump to around 1800, once it comes back down it blows off pressure again and starts all over.

anyone have tips for this boost noob?

 

[blown98gt]

is your setup for a blow-thru maf or draw-thru maf because depending on the setup you might need to revent the air into the pipe vs just letting it vent into the air. Sounds like you might have it setup the wrong way. draw-thru setups must have the bypass revented, and blow-thru setups do not.

http://sn95forums.com/index.php/topic,37141.0.html

read up that should help you understand it a lil more

 

[sn95gtvert]

thank you! very good information in there.

i have a draw thru setup and my bypass is setup like a bov creating more surge. i unhooked it and it runs fine but im paranoid about down shifting and using the engine as a brake.

 

[blown98gt]

as long as you revent the air into your setup you wont have any issues. I'll look through my pictures when I get home and see if I have a good picture of how my procharger race bypass was setup and i'll put it up on here for you.

 

[IceMan]

You have to recirculate the the bypass valve. You can't use it like a BOV on a draw through set up. Also make sure that it's hooked up the right way.

 

[sn95gtvert]

yeah i figured that out about recirculating it pretty fast when it didn't work right. my friend i got the kit from told me it would work like a bov but he was wrong and i researched to little before adding it. its disconnected atm until i can get a new bosch bypass and do it right.

 

[blown98gt]

that's probably the best route the other option if you want to keep a bov type sound is relocate your maf from the s/c intake pipe to the actual intake pipe. lightning maf's can be used as a blow thru maf. but moving from a draw thru to a blow thru requires tuning

 

[sn95gtvert]

yeah tuning is the last thing on my mind right now. stock cam with 6psi no codes getting thrown and it runs damn hard from what it was N/A.

as you can see i dont have much room to move the maf after the blower. im going to go the bosch route and not worrie about it.

 

[blown98gt]

that is probably the best route, you can go. after reading that thread i wrote awhile back do you understand why it was surging though? due to be a draw thru setup, you must recirculate the air in order for it to work properly (if you had an intercooler you could change to a blow thru setup)

 

[sn95gtvert]

i understood it and it makes a lot more sense in now. as you can see the bypass i have has no way of recirculating so it'll only act like a bov. i'll go the bosch route as soon as i can.