APS - Swap out stock BOV's for atmospheric units???
I know it is a stupid question, but after a year and almost 8,000 miles with my APS TT kit (which I LOVE), I am tired of it being so darn quiet! So I wanted to know if anyone has done it or has any input (Peter) on swapping in atmospheric blow off valves? Can it be done without any A/F issues (and no change in drivability), or will it require tuning? Are they accessable from the fender wells?
I liked the total sleeper thing for the past year, but now everyone and their mother knows what I have, so I might as well crank up the volume for effect!
Hey Tom, not a stupid question at all, I feel your pain...I personally didn't favor the plastic Bosch valve myself, and how well the diaphragm can sustain high-psi (10+) is questionable and all too quiet for my taste.
BOV dumps is probably not a good idea if your running a MAF setup; what will happen is that the mass air-flow sensor will account for the air and then the BOV will vent it to atmosphere. This means that the fuel injectors will supply enough fuel for the air that was vented to the atmosphere, creating a very rich condition.
I run a 2 bar speed density tune (mafless); the drivability is amazing at both part throttle and WOT, the power transition is smooth. Also, it allows me to dump my BOV to atmosphere w/o any affects. I chose the Forge Motorsport FMDV004 since it's a twin spring and dual piston unit to prevent from leaking air, and also well built much like the Forge wastegate actuator I'm using.
Yes, you can access them thru the front wheel wells, remove the wheels and pop the panels out:
Here's an old clip of the Bosch valves venting to atmosphere; this was taken back in Jan. at low boost with 150 miles on the new motor:
[IMG][/IMG]
I don't have a clip of the FMDV004; only to say they are MUCH LOUDER!!!
Next up external wg dump to atmosphere....shooting for SPL.
Thanks for the info Brabus. I'd just rather have external wastegates too!!!
So the car will run rich with a MAF system... hmmm... I really would like to drive my car after next year (ie. pass CT state emissions) and I can't do that without the MAF intact. There has to be something else... A lot of the Subaru and Mitsu guys run 100% atmospheric in their cars without a problem...
Actually installing the BOV's in place of the recirc valves won't affect the MAF readings or performance of the MAF, since the recirc valves are positioned inbetween the turbo and MAF, not between the MAF and the engine, thus releasing the air before it gets to the MAF before reading the airmass. It would only affect it if they were placed between the MAF and the engine, after MAF reading and releasing before it gets to the engine but being accounted for in the fuel calculation. The BOV's will have to be adjusted for the application by changing the springs for the correct boost level, they have three or four different spring pressures for different boost levels. They have to be adjusted properly to work in conjunction with the wastegates, and you may need to tweak the PCM program for for the release area so you don't have any hesitations or air stall.
Tom, we carry the Forge BOV's in different configurations for each application, give me a call if you need some. Good Luck, Geoff.
Actually installing the BOV's in place of the recirc valves won't affect the MAF readings or performance of the MAF, since the recirc valves are positioned inbetween the turbo and MAF, not between the MAF and the engine, thus releasing the air before it gets to the MAF before reading the airmass. It would only affect it if they were placed between the MAF and the engine, after MAF reading and releasing before it gets to the engine but being accounted for in the fuel calculation. The BOV's will have to be adjusted for the application by changing the springs for the correct boost level, they have three or four different spring pressures for different boost levels. They have to be adjusted properly to work in conjunction with the wastegates, and you may need to tweak the PCM program for for the release area so you don't have any hesitations or air stall.
Tom, we carry the Forge BOV's in different configurations for each application, give me a call if you need some. Good Luck, Geoff.
Good info and glad to hear from you! Thanks Geoff.
Actually installing the BOV's in place of the recirc valves won't affect the MAF readings or performance of the MAF, since the recirc valves are positioned inbetween the turbo and MAF, not between the MAF and the engine, thus releasing the air before it gets to the MAF before reading the airmass. It would only affect it if they were placed between the MAF and the engine, after MAF reading and releasing before it gets to the engine but being accounted for in the fuel calculation. The BOV's will have to be adjusted for the application by changing the springs for the correct boost level, they have three or four different spring pressures for different boost levels. They have to be adjusted properly to work in conjunction with the wastegates, and you may need to tweak the PCM program for for the release area so you don't have any hesitations or air stall.
Tom, we carry the Forge BOV's in different configurations for each application, give me a call if you need some. Good Luck, Geoff.
So you're tellin' me there's a chance?! Thanks for the insight Geoff.
Any sound clips of the Forge units? Are they 100% atmospheric? Adjustable?
I know it is a stupid question, but after a year and almost 8,000 miles with my APS TT kit (which I LOVE), I am tired of it being so darn quiet! So I wanted to know if anyone has done it or has any input (Peter) on swapping in atmospheric blow off valves? Can it be done without any A/F issues (and no change in drivability), or will it require tuning? Are they accessable from the fender wells?
I liked the total sleeper thing for the past year, but now everyone and their mother knows what I have, so I might as well crank up the volume for effect!
Thanks,
-Tom
Tom,
Personally, I wouldn't bother. It can be done, and yes external BOVs are better than internal BOVs for potential. Will it make noise? Pretty much, of course. Is it worth it for $ for the performance gain? NOT!!!
EXPECTATIONS:
The turbo sizing is WAY too small for the application. It is a very SAFE kit from APS. Excellent low to mid response as you know, but of course the air volume lacks on the high end and with the size and weight of the excellent intercoolers they use it makes it very tough to "break" a stock motor easily from boost/heat. It doesen't matter what you do to mod the kit, the main issue always comes back "to haunt" and I doubt you will ever see any significant HP/TQ gain regardless from any external BOV, downpipe, exhaust type modification(s) on the kit. Trying to find room is a major issue down there anyway!!!!
It's like putting two factory T3 turbo housings, internally BOV'ed on any 6.0 + liter motor and expecting performance perfection. It's not going to happen regardless. There just isn't enough maximum airflow by any turbo makers recommendation for that CID. Every mod is going to have very little effect when the major issue is always going to be "lack of high end airflow" to make HP/TQ from turbos that are too small for the CID of that motor to make max power efficiently.
I would suggest selling the stock C6 kit and getting the APS C6 Z06 kit as it uses GT35R turbos, which won't spool as fast, but will net you much more power and they are already BOV'd externally as well. Just a thought? I believe the kit will "retrofit" as well, but I would double-check with APS!!!
I don't get what modifying the stock APS C6 kit is ever really going to "net you" significantly performance wise, nor by the $ aspect of pursuing it with the small mods on that system.
Personally, I wouldn't bother. It can be done, and yes external BOVs are better than internal BOVs for potential. Will it make noise? Pretty much, of course. Is it worth it for $ for the performance gain? NOT!!!
EXPECTATIONS:
The turbo sizing is WAY too small for the application. It is a very SAFE kit from APS. Excellent low to mid response as you know, but of course the air volume lacks on the high end and with the size and weight of the excellent intercoolers they use it makes it very tough to "break" a stock motor easily from boost/heat. It doesen't matter what you do to mod the kit, the main issue always comes back "to haunt" and I doubt you will ever see any significant HP/TQ gain regardless from any external BOV, downpipe, exhaust type modification(s) on the kit. Trying to find room is a major issue down there anyway!!!!
It's like putting two factory T3 turbo housings, internally BOV'ed on any 6.0 + liter motor and expecting performance perfection. It's not going to happen regardless. There just isn't enough maximum airflow by any turbo makers recommendation for that CID. Every mod is going to have very little effect when the major issue is always going to be "lack of high end airflow" to make HP/TQ from turbos that are too small for the CID of that motor to make max power efficiently.
I would suggest selling the stock C6 kit and getting the APS C6 Z06 kit as it uses GT35R turbos, which won't spool as fast, but will net you much more power and they are already BOV'd externally as well. Just a thought? I believe the kit will "retrofit" as well, but I would double-check with APS!!!
I don't get what modifying the stock APS C6 kit is ever really going to "net you" significantly performance wise, nor by the $ aspect of pursuing it with the small mods on that system.
Go BIG dude!!! Forget the small stuff!
JJ, thanks for the write up, but this is my 4th turbo'd car so I know all the basics. Not once in my original post did I mention I wanted more "performance" from new BOV's... I'm only looking for sound. As far as ditching the C6 APS kit for the Z06 kit; thanks but no thanks. I'd love an EWG setup more than you know, but the C6 kit is already capable of 850+ HP and this is my street car/daily driver... I have no want or need for much more power than I am already making or building the motor to support higher levels. I am probably going to do a meth kit soon but only for the basic benefits and maybe a 50 HP bump and I'll be happy. I am content with running my current boost/power levels for now. If I want a sub 10 second drag car, I'll pick a better platform to start with than a new Corvette.
So like I said in the OP, all I want is a little more sound by replacing the plastic resirc' valves...
JJ, thanks for the write up, but this is my 4th turbo'd car so I know all the basics. Not once in my original post did I mention I wanted more "performance" from new BOV's... I'm only looking for sound. As far as ditching the C6 APS kit for the Z06 kit; thanks but no thanks. I'd love an EWG setup more than you know, but the C6 kit is already capable of 850+ HP and this is my street car/daily driver... I have no want or need for much more power than I am already making or building the motor to support higher levels. I am probably going to do a meth kit soon but only for the basic benefits and maybe a 50 HP bump and I'll be happy. I am content with running my current boost/power levels for now. If I want a sub 10 second drag car, I'll pick a better platform to start with than a new Corvette.
So like I said in the OP, all I want is a little more sound by replacing the plastic resirc' valves...
Turbo Tom, Im thinking of getting the APS kit. What kind of power are you making on the stock motor? What will these stock motors take? I use to have a turbo 04 cobra so i have no idea about these chevys. Any dislikes about the kit so far?
The real question is to you.
What are YOU looking for when you build your car?
Big power(800+rwhp) or a great, driveable 600rwhp on stock internals and pump gas?
They are definitely different goals.
I have the C6 kit which I retrofitted on my c5, and I love it.
I still think it has the capability to put out some very big power on a 347 cube or 360 cube engine, but until I do a head/turbo cam/forged setup, I won't know.
Probably next year.
Torque is pretty much instantaneous with this kit on a stock car, and most guys are seeing near 600rwhp/600rwtq on a stock c6.
For instance, I recently bought a Performance Box from Racelogic, and I set it up to do some 60-130 testing.
On a closed airstrip, I've seen consistent 60-130 times in the 7.5 second range, with one shift from 3rd to 4th.
To put it in perspective, a stock Porsche Carrera GT does it in about 7.4 seconds, so bang for the buck, my car really moves!
Anway, just some things to think about before you buy any FI kit.
Do ALOT of searching/reading on this forum, and you'll have all the info you need to make a good, informed choice.
Good luck.
__________________ 2002 QS MR Z06 APS TT RPM/Quicktime Blowshield, RPS Triple Carbon Clutch, DTE Brace and L&R Shafts, FJO Wideband, Full 3" exhaust w/LGMotorsports Big 3" Mufflers & 3" High Flow Cats 560rwhp 570rwtq
Mustang Eddy Current Dyno Results
60-130 6.89secs Performance Box GPS verified
The real question is to you.
What are YOU looking for when you build your car?
Big power(800+rwhp) or a great, driveable 600rwhp on stock internals and pump gas?
They are definitely different goals.
I have the C6 kit which I retrofitted on my c5, and I love it.
I still think it has the capability to put out some very big power on a 347 cube or 360 cube engine, but until I do a head/turbo cam/forged setup, I won't know.
Probably next year.
Torque is pretty much instantaneous with this kit on a stock car, and most guys are seeing near 600rwhp/600rwtq on a stock c6.
For instance, I recently bought a Performance Box from Racelogic, and I set it up to do some 60-130 testing.
On a closed airstrip, I've seen consistent 60-130 times in the 7.5 second range, with one shift from 3rd to 4th.
To put it in perspective, a stock Porsche Carrera GT does it in about 7.4 seconds, so bang for the buck, my car really moves!
Anway, just some things to think about before you buy any FI kit.
Do ALOT of searching/reading on this forum, and you'll have all the info you need to make a good, informed choice.
Good luck.
This is excatly what im trying to do. Some research so i can find excatly what to do. Im located in south florida. who are some people i can be calling about setups? What kind of power are head/turbo cam aps kit tt setups doing?
This is excatly what im trying to do. Some research so i can find excatly what to do. Im located in south florida. who are some people i can be calling about setups? What kind of power are head/turbo cam aps kit tt setups doing?
That's my point.
Read all you can on the C5 and C6 FI forums, because almost all your questions have probably been asked.
Look at all the different types of results that people have been getting here, and you should be able to make a good informed decision.
So you're tellin' me there's a chance?! Thanks for the insight Geoff.
Any sound clips of the Forge units? Are they 100% atmospheric? Adjustable?
Tom,
I have a car here with Forge BOV's on it, I'll try and get a sound clip for you, they are 100% atmospheric, and adjstable by changing out the internal springs.
Martin,
You can stop by and hear them if you want.
Richard,
It looks like in your pictures you are using the Forge 27mm BOV's and you can fit the 34MM BOV's (more volume) in there by not using the silicone sleeve on the unit.
It looks like in your pictures you are using the Forge 25mm BOV's and you can fit the 34MM BOV's (more volume) in there by not using the silicone sleeve on the unit.
Thanks, Geoff.
Geoff, yes they are in fact the 27mm...Luis suggested to use these, however I should have called you first for your opinion! Thanks for looking out.
Martin, go for it! Not only will the peeps be checking-out your badass hotrod for the looks, now you'll have the sound to make them go
I have a car here with Forge BOV's on it, I'll try and get a sound clip for you, they are 100% atmospheric, and adjstable by changing out the internal springs.
Thanks, Geoff.
Sweet! I am really glad this won't be a problem. Right now I am considering two other manufacturers, so I'd love to hear the Forge units before I make a final decision...
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APS - Swap out stock BOV's for atmospheric units???
So I wanted to know if anyone has done it or has any input (Peter) on swapping in atmospheric blow off valves? Can it be done without any A/F issues (and no change in drivability), or will it require tuning? Are they accessable from the fender wells? 
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I'd just rather have external wastegates too!!! 
