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BOV placement

OK so i am still working out my efi swap and collecting parts. I was wondering the best place for the BOV. Since it's designed to protect the compressor should it be installed on the inlet to the inter-cooler? Or should it be installed on the outlet of the inter-cooler for faster boost after you get back on the the throttle. I have seen the installed in both places. Just wondering from a design standpoint which is best
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 10-08-2011, 01:12 AM
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hey ken, ive often heard that just before the throttle plate is best and thats where i installed mine. works great
Old 10-08-2011, 04:04 AM
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You see i would think just the opposite since the intercooler provides back pressure. I would think it should be as close to the trubo as possible. I have seen so many pictures of them installed in both places by different builders. Hows yours working by the way did you go to the ms-3 or stay with the ms-2? Did you end up having Eddie build you an intercooler like Juans?
I'm going to be using the ms-3 since i plan on using coil on plugs.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue

Last edited by Ken911; 10-08-2011 at 04:20 AM..
Old 10-08-2011, 04:11 AM
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I put mine between the turbo and intercooler.

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Old 10-08-2011, 07:52 AM
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I don't know if you'd notice a difference where you mount it if the intercooler is big and flows good - before the core or after it.
The chosen location may come down to where it fits best and is not going to get wet from rain or car washing on a street car.

I understand your logic so ask some experts like Chris at Turbokraft.
Old 10-08-2011, 08:04 AM
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The BOV can be mounted anyplace between the (Turbo Outlet) and the
(Throttle Body).

Cole
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Old 10-08-2011, 11:00 AM
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Quote:
Originally Posted by cole930 View Post
The BOV can be mounted anyplace between the (Turbo Outlet) and the
(Throttle Body).

Cole
Yeah i know it can be mounted in either place but my question was which one is the best place.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 10-11-2011, 01:10 AM
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Quote:
Originally Posted by JFairman View Post
I don't know if you'd notice a difference where you mount it if the intercooler is big and flows good - before the core or after it.
The chosen location may come down to where it fits best and is not going to get wet from rain or car washing on a street car.

I understand your logic so ask some experts like Chris at Turbokraft.
yeah i sent pm to Chris but i guess he didn't get it I'll call him when i get off night shift. I have also been trying to find as many pics of Juans intercooler as I can. The one i am building is going to be as close to his as possible. I like it better than any of the other custom ones i have seen.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue

Last edited by Ken911; 10-11-2011 at 01:15 AM..
Old 10-11-2011, 01:12 AM
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1. One factor is physical available demensional space, some people also place it closer to the throttle and this typically does two things.

Vent's hot gasses which depending on location can be bad and reduce response and recovery because you are de-pressurizing anything after the BOV. Usually a big loud woosh, unless you are boosting so much that you can just waste it.

2. You want it closer to the throttle. You want pressure to be stabilized and to reduce the amount of normalizing / recovery time. Especially if you are bleeding off and not using a re-circulating set up. In short, the idea is to keep the system pressurized an to not have to re-pressurize the entire system and be on stand by ready to resume.

3. Blow off valves are a little sloppy, excellent if you produce so much boost that you can afford to just waste it. Think about a circulating type system.
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Old 10-11-2011, 02:26 AM
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ken its working great! i did end up using the ms 2 and have created an awesome tune. great afrs and huge flames. still have to pull heads and open up intake ports and twin plug before i install my garrett "blowzilla" and i am getting my full bay from bell. should be very soon. put the bov near the tb as it works great and you have more room to work
Old 10-11-2011, 02:49 AM
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Turbo books and papers I've read say put the BOV as close to the throttle body as possible.
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Old 10-11-2011, 03:32 AM
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[QUOTE=Schwarzeritter;6304227]
2. You want it closer to the throttle. You want pressure to be stabilized and to reduce the amount of normalizing / recovery time. Especially if you are bleeding off and not using a re-circulating set up. In short, the idea is to keep the system pressurized an to not have to re-pressurize the entire system and be on stand by ready to resume.

OK thanks guys this was the answer i was looking for i wanted to know if the back pressure caused by the core of the inter-cooler and resulting stress on the turbo outweighed the quicker spool up when you get back on the throttle.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 10-11-2011, 03:42 AM
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Quote:
Originally Posted by xbmwguy View Post
ken its working great! i did end up using the ms 2 and have created an awesome tune. great afrs and huge flames. still have to pull heads and open up intake ports and twin plug before i install my garrett "blowzilla" and i am getting my full bay from bell. should be very soon. put the bov near the tb as it works great and you have more room to work
Glad it's working good for you I thought you were planning on having Eddie make you an intercooler like Juans. I'm ordering the core next week i think just need to dig up all the old pics i took when we were at the show to see if i can keep my rear window wiper with it. Plus i have to get the tig out and practice up. Other wise i'll tack everything together and have one of the guys at work weld it up. I have my spare set of heads ported to match the 3.2 intake and the valves done. need to take them up to extream and get them drilled for the extra plugs still. Are you planning on staying with the ms-2 when you go to twin plugs?
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 10-11-2011, 03:51 AM
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yep for now. the car is making great power and torque with stock intake and the 7006, and honestly darrin has helped when he could but ive done most of this tuning in baby steps and what a learning exp. it has been. i am actually glad i did do it from wiring to tune as i now have a much better understanding of what is going on
Old 10-12-2011, 12:54 PM
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Porsche Crest BOV Location

For what is worth, here is my two cents.

I spoke directly with the engineers at Tial and they specifically told me that the best location is as close to the throttle body as possible. The theory is that the charged air (compressed) will simply dump out at the blow off valve and not effect the compressor speed. This, of course, is based on having the correct spring rate and vacuum line connection point.

Based on that information, I fabricated a 964 intercooler with the BOV mounted directly next to the discharge nozzle. I have attached several photos for reference. The results are astounding to say the least. My turbo has zero lag between shifts and feels more like a normally asperated engine from 1500 rpm's and up.

My vote, of course, goes for the "nest to the throttle body" side.


Thank you,
Rich

Old 10-13-2011, 12:26 PM
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Having thought about this more since this thread started, mounting the BOV next to the throttle body or on the exit side end tank near the TB would keep the air flow from reversing in the core passageways when closing the throttle during boost.

If the BOV was on the charge pipe or charge pipe side end tank then pressurized air inside the core and exit side end tank that is moving towards the TB would reverse direction to blow out the BOV when the thottle butterfly closes and resulting intake manifold vacuum opens the BOV.

Not a good thing because it seems that would increase turbo lag when getting back on boost as air flow through the core reverses direction again to flow towards the opened throttle body.

BOV mounted near the TB should keep air flowing through the core in the same direction all the time.
Old 10-13-2011, 12:45 PM
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yeah that makes sense It will be just before the throttle body. Decision made i'll make up a short straight piece that fits between the two elbows on the intercooler outlet.
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88 turbo Guards red Targa slant nose, and yes I am a horsepower junkie, 3.4liter,7.5 to 1 JE pistons, Adjustable WUR, Imagine fuel head, 1 bar waste gate headers,allthe cis toys. Now apart to become the next EFI monster. fabbing my own intake, headers Individual throttle bodies, MS-3, pauter rods, Xtreme twin plugged heads, gt-2 evo cams cop's.
05 Cayenne S lapis blue
Old 10-13-2011, 08:07 PM
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