blow off valves?

[bersh240]

ok im getting my car tuned on monday at a local high performance shop. the guy doesnt remember ever tuning a ca before and told me to get a list of all the stuff my car has so he can do some research. so i was in the ca section searchin around found that you have to recirculate the bov on a ca. since im a 16 year old that has alot to learn i have no idea what that means. i tried lookin it up and it all just confused me. cuold someone explain this so i know if my cars gona blow up or something?

[Elbowblk]

recirculating the blow off valve simply means that instead of making the blow off valve vent the boost out into the air, that it sends it before the turbo but after the maf so you'll still have the recorded air that passed through the maf already.

heres a good pic. see the blow off valve? and then see the red tube on the right side that leads into the intake before the turbo but after the maf.

[bersh240]

oh but itl make the noise go away? thats what makes all the ladies love my car cuz all the lil civis run away.is it really important to do it tho?

[tEknoS13]

I don't see why it is necessary to do so. Last time I checked people just do it because they get fed up with the noise, and some claim it gives you an extra push (power) Better look it up though man. Sorry for lack of help...

BTW: it will make the sound go away.

[bersh240]

in the ca mod thread thingy it says to recirculaate it. i no u dont HAVE to for other engines but why does it tell me to do so on the ca?

[safin]

makes the civics run away, and that gets you the ladies?...

then let it vent to the atmosphere. if your guy working on the car does not know what a BOV does and seems sketchy about it. take your car somewhere else. please.

BTW """""what are you tuning it for?... maybe is something you could do using the info on the forum. that way you get learned and you'll love your car even more...... unless you are really doing some hardcore mods

[bersh240]

the guy is an ex gm engine developer guy and is an expert in tuning and has the whole in shop floor dyno and all that good stuff. hes a good tuner. but speacilizes in drag cars and such and hasnt worked with a ca in years. and since the thread told me to recirculate it it just worries me that it isnt. basically the answer im looking for is why does the CA18det need to have a recirulated bov? and will it harm my engine if it isnt?

[bersh240]

its running really rich and at 5500 rpm it bogs down and acts funny and since its on the stock tune i figured that should work alot of the bugs out. so.. im tunning it to be a dd with some balls.

[the_momo]

the guy is an ex gm engine developer guy and is an expert in tuning and has the whole in shop floor dyno and all that good stuff. hes a good tuner. but speacilizes in drag cars and such and hasnt worked with a ca in years. and since the thread told me to recirculate it it just worries me that it isnt. basically the answer im looking for is why does the CA18det need to have a recirulated bov? and will it harm my engine if it isnt?

wWth any mass air flow metered engine you need to recirculate the bov if the maf is before the turbo i.e. "draw through" as is the way they ca and all stock turbo maf cars are, the pressure loss when venting the bov that is after the maf causes the engine to stumble because of the pressure loss from the bov opening.

If you are running a "blow through" maf setup, you can place the bov before the maf and vent it, as there is no pressure loss after the maf. Likely you will not be running a blow through setup as it requires a lot of tuning changes for little benefit on a mostly stock setup.

If you are looking for a setup that runs and idles like stock, I suggest making it as "stock" as possible in terms of its layout. Draw through maf (maf before the turbo) and recirculate the bov (after the maf, before the turbo. between them)

This will ensure the proper readings on the maf, and wont cause your car to bog or stumble.

Also if your tuner says he wants you to do leg work to find out about your setup, he is eiher trying to teach you or has no idea what he is talking about, in any event i would highly suggest taking your car to someone who has a lot of and recent experience tuning ca18's. they arent like sbc, unfortunately.

[the_momo]

I also reccomend this:

http://www.amazon.com/Maximum-...01606

Its a good read and a must for any high performance enthusiast's library.

[bersh240]

so.. basically im gona lose the awsome sound. lose a lot of money. and lose alot of time this weekend. all to get rid of a stumble that happens when the bov opens.. which doesnt happen. theres only a stumble at almost 6k wen the bov shouldnt be doing anything really.. right?the stumble i think is a fuel issue.. but the cars been running without the bov recirculated since the swap and its fine..

[busteds13]

your stumble prolly has very little to do with the BOV, I've been running a crushed stock DSM BOV, vented to atmosphere, and have had no problems for 2-3 yrs, the thing that vented to atmosphere causes is richness right after it sneezes out air, ( MAF read more air than engine got, because said air is now in engine bay rather than IC piping, but computer thinks its still in the piping, so it dums the appropriate amount of fuel in the the cylinders, but the air is not there, so car goes rich at that moment.)Now this bit is usually handled by tim, (R34 gtr); but since hes not said it yet;Hows your grounding situation? a few well cleaned and placed grounding straps may fix all your issues. i had stumbling too and the grounding straps relieved alot of the problem.

Also is the car stock? or are there internal mods? How is this GM guy gonna tune this thing? Besides of course a dyno and a wideband?

BOV should not cause stumble, unless you have the vac routing funny, or it just stays open and dosent close?

Check your plugs, they may bee too cold, or the gap is too big, or too small, or your coil packs start wiggling at that RPM and loose ground, hence losing spark and causing stumble.

Basically you shouldent need a tune if the engine is stock, once you start swapping MAFS, Injectors, Turbo, etc. then you NEED a tune, the stock ECU even though it is pretty Simple-Stupid, should run the car good in stock form, unless you molested something somewhere you shouldn't of......

[bersh240]

well theres a t28 turbo on there.. deff time for a tune anyway. but i never thought of the grounding straps. and i keep meaning to check the plugs but keep doing body work instead. stupid i no. and i have an eprom thingy that hes gona tune with too. thanks alot thats what i needed.

[Elbowblk]

you may run your bov unrecirculated if you have a safc. or so i read.

and recirculated isnt too bad. i still hear my bov when i hit full boost.

[rico05]

This thread is so full of fail.

I have run both an ARC Type 3 (push valve) and an HKS SSQV version 2. The ARC would leak at idle as it is designed to be recirculated and since I prefer to vent, I switched to a pull type valve. I run through standard plugs in about a month and iridiums in about 4-5. Just part of it. For heavily fueled motors, I highly reccomend recirculating. Even at higer than stock fuel pressure, with standard 370s and venting at 12+psi I get no stumble. You have a ground or overfueling issue.

[RS12Turbo]

No prob venting my hks ssqv to atmosphere...3 years running Other brands yes....will cause idle issues, etc