BOV Comparo... BOSCH vs. DSM
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BOV Comparo... BOSCH vs. DSM
OK, just got done with my baseline pull with my OEM BOSCH bypass valve. It came (advertised) from a low-mileage Saab 9-series... so who know's how much it's good for. I think most guys give it a 15psi max while others say (on a good day) it'll give you 10psi.
You can see by my DATALOG that in every gear except 1st, I spike immediately to 14psi and settle steadily to 12psi by redline. No amount of ******* with the EBC tables will let me run more boost. So either my T25 won't give me the air (not likely) or by BOV isn't up to par.
I know I'm a ***** for shifting at 6500
And for some reason, it won't let me upload the Excel datalog?
You can see by my DATALOG that in every gear except 1st, I spike immediately to 14psi and settle steadily to 12psi by redline. No amount of ******* with the EBC tables will let me run more boost. So either my T25 won't give me the air (not likely) or by BOV isn't up to par.
I know I'm a ***** for shifting at 6500
And for some reason, it won't let me upload the Excel datalog?
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Sam: Well, I hit a snag.
Collective: NO, really... we thought this would go off swimmingly.
Sam: Yah, big shock.
First thing is pretty obvious. Silicone will stretch pretty good if you put it in a pot of boiling water for 20mins... but it't not gonna stretch far enough to get that pipe inside the T-junction. So I'm taking suggestions for that. I might end up blowing $40 on a new T-coupler unless somebody knows where I can get a 1" adapter plate.
Second is the strange oil pattern inside my coupler. I can't see any way that oil is there. Anybody seen that before?
Collective: NO, really... we thought this would go off swimmingly.
Sam: Yah, big shock.
First thing is pretty obvious. Silicone will stretch pretty good if you put it in a pot of boiling water for 20mins... but it't not gonna stretch far enough to get that pipe inside the T-junction. So I'm taking suggestions for that. I might end up blowing $40 on a new T-coupler unless somebody knows where I can get a 1" adapter plate.
Second is the strange oil pattern inside my coupler. I can't see any way that oil is there. Anybody seen that before?
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Serious, or are you trying to get me to burn my house down?
Well, I hope nobody got too excited to see the results of this tonight. Looks like my best bet is to buy a new flange and have a 1" nipple welded to it. There is no T-coupler sold that will work, oh well. I'll keep y'all posted.
EDIT: I just boiled, microwaved, and submerged in KY and there's no ******* way that thing is going on. Anybody in Hampton Roads weld?
Well, I hope nobody got too excited to see the results of this tonight. Looks like my best bet is to buy a new flange and have a 1" nipple welded to it. There is no T-coupler sold that will work, oh well. I'll keep y'all posted.
EDIT: I just boiled, microwaved, and submerged in KY and there's no ******* way that thing is going on. Anybody in Hampton Roads weld?
Last edited by samnavy; 07-11-2008 at 07:27 PM.
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JBWelder to the rescue!
Why weld when you can JBWeld? I was running low on aluminum stock anyways... one trip to TaylorsDIY (which I love) and I'm replenished and tomorrow this thing will go in and I'll have the proof about OEM Bosch BOV's.
Last edited by samnavy; 07-13-2008 at 12:51 PM.
#7
2 little notes:
It would have been more ideal to make the tube fit into the flange. Maybe whip out something fancy like a really tight tolerance where you heat the flange and freeze the tube for a super tight fit.
I would also suggest a thicker application or several applications of the JB goodness
It would have been more ideal to make the tube fit into the flange. Maybe whip out something fancy like a really tight tolerance where you heat the flange and freeze the tube for a super tight fit.
I would also suggest a thicker application or several applications of the JB goodness
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Yup, that would be the better solution, but there's really no stress on it, all the flex will happen in the silicone... good advice, hopefully not following it doesn't bite me.
RESULTS:
1) It makes the most absurdly annoying flutter when it vents. The BOSCH is a simple whoosh of air. This thing flutters like it has a pair. It'll open and flutter at the slightest hint of vaccum. Fffft, ffft, ffft, fffft, ppssssttt. It's actually not bad at WOT shifts, but at low boost or part throttle, it's not something I can live with on a daily basis.
2) It makes absoultely no difference in performance. Backed up by a very thorough analysis of my datalogs, there's zero improvement.
3) And since it made no difference, I got to thinking about my turbo... and cranked up the EBC values. 10pts made no difference in max-boost. No matter how high I put the values, I get a spike to 14psi settling to 12psi at redline. I think that's the limit of my little T25.
Here's a side-by-side boost graph 2-3-4 shifting. Both lines are near enough to identical not to matter. The thick line is the BOSCH BASELINE. The skinny line is the DSM after the 10pts on the EBC. I attribute the extra .5psi below 5k to the the EBC increse... but the fact that they're idential above 5k indicates to me I'm at the limit of the turbo.
RESULTS:
1) It makes the most absurdly annoying flutter when it vents. The BOSCH is a simple whoosh of air. This thing flutters like it has a pair. It'll open and flutter at the slightest hint of vaccum. Fffft, ffft, ffft, fffft, ppssssttt. It's actually not bad at WOT shifts, but at low boost or part throttle, it's not something I can live with on a daily basis.
2) It makes absoultely no difference in performance. Backed up by a very thorough analysis of my datalogs, there's zero improvement.
3) And since it made no difference, I got to thinking about my turbo... and cranked up the EBC values. 10pts made no difference in max-boost. No matter how high I put the values, I get a spike to 14psi settling to 12psi at redline. I think that's the limit of my little T25.
Here's a side-by-side boost graph 2-3-4 shifting. Both lines are near enough to identical not to matter. The thick line is the BOSCH BASELINE. The skinny line is the DSM after the 10pts on the EBC. I attribute the extra .5psi below 5k to the the EBC increse... but the fact that they're idential above 5k indicates to me I'm at the limit of the turbo.
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"Hooked up correctly?" You mean like I attached a coolant hose to the vaccum port or something?
It may be a product of the very small exhaust port I've got. My JBWelded adapter is only a 1" pipe where the overall size of the port on the unit is at least 1.5"... it might be causing some weird feedback. All I really know is that it flutters when I even think about lifting. It's almost fluttering when I simply stop accelerating... and it flutters for about 2 seconds... a really long time.
I'll get some video/sound tonight for y'all.
As for "crushing", I've been told from very reliable sources that the stock 1G BOV is good for 22psi, and crushing will let you run 30+psi. This is the standard blurb on the DSM boards as well. The Subie BOV's must be different as it's considered general knowledge that running a crushed 1G DSM BOV is the budget way to go for any budget DIY system.
All this thread proves is that MY PARTICULAR OEM BOSCH BOV works as advertised and does not leak under boost.
It may be a product of the very small exhaust port I've got. My JBWelded adapter is only a 1" pipe where the overall size of the port on the unit is at least 1.5"... it might be causing some weird feedback. All I really know is that it flutters when I even think about lifting. It's almost fluttering when I simply stop accelerating... and it flutters for about 2 seconds... a really long time.
I'll get some video/sound tonight for y'all.
As for "crushing", I've been told from very reliable sources that the stock 1G BOV is good for 22psi, and crushing will let you run 30+psi. This is the standard blurb on the DSM boards as well. The Subie BOV's must be different as it's considered general knowledge that running a crushed 1G DSM BOV is the budget way to go for any budget DIY system.
All this thread proves is that MY PARTICULAR OEM BOSCH BOV works as advertised and does not leak under boost.
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