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Discussion Starter · #1 ·
Hey guys! I have a question. Why do some DSMs blow off louder than others? I have a friend with a 99 GST. We have generally the same mods except I have an exhaust and a MBC (set to 15#). We both have the Greddy Type S bov. But his seems to blow off 'louder' than mine?!? Mine blows off pretty hard at around 5-10PSI but I've seen his blow off pretty hard when he's going into second gear (and thats normal driving - not punching it or anything). May I have a leak or something or maybe a defective bov? or maybe its just the way I drive vs. the way he drives? Also, I've tested the car with the BOV with the stock airbox. I could barely hear it blow off with the stock airbox installed. But when I have the BOV with the K&N, it blows off even louder? I don't get it. Thanks for the input.

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Ray
1998 Eclipse GST
Mods: 3" Thermal R&D, Greddy TypeS bov, dump tube removal, MBC, Sprint Lowering springs, strut bars, Autometer gauges, HKS timer, custom interior, 17" performance rims

 

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Do you guys both have your BOV's spring set to the same level? (i.e. is his set softer than yours)????

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'92 Eclipse GS 2.0L NT
http://www.geocities.com/trueracers
 

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Discussion Starter · #3 ·
setting is about the same. we both have it on the hard setting (mine is exactly the same as the setting on the RRE website - how to install the IC piping section). will it blow off harder if its on the soft setting?

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Ray
1998 Eclipse GST
Mods: 3" Thermal R&D, Greddy TypeS bov, dump tube removal, MBC, Sprint Lowering springs, strut bars, Autometer gauges, HKS timer, custom interior, 17" performance rims

 

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Yo what's up man! Was that you on the 805 and 163 freeway at like 1:30 in the morning last night? Anyways when I was adjusting my Greddy Type-S and I set it really soft... then the spring was allowed to expand since you loosen the spring to make it "soft", and its easier(softer) to push the spring(hence it's easier to blow off. Mine would blow off in 5 vacuum.. too soft. And if you make it "hard", you screw the screw tighter... making the spring harder to compress. A compressed spring is "harder" to compress(assuming it's the same spring obviously) than the "softer" spring which is less compressed. I understand it but I had a hard time explaing it... I hope you guys didn't get confused from my attempted explanation.
 

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Discussion Starter · #5 ·
Sup Mike. Nah, that wasn't me on 805 last night. Must've been someone else. Didn't make it to the races last night (had a long and busy day). How was it? Was it busy as usual? Thanks for the input. My setting is probably too "hard" (spring compressed alot more?). Maybe I should soften it up a bit. I just don't like the throttle respones on the soft settings. My car feels really sluggish with that setting. I guess I'll have to do without the louder whooooooooooooosh for now. hehehehe!

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Ray
1998 Eclipse GST
Mods: 3" Thermal R&D, Greddy TypeS bov, dump tube removal, MBC, Sprint Lowering springs, strut bars, Autometer gauges, HKS timer, custom interior, 17" performance rims

 

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Yo man, I didn't see any races cause after about 45 minutes I got pulled over for no front plate. The guy saw my exhaust as was gonna get me for that... I asked a bunch of questions and asked for vehicle code numbers... and he let me go for just the front plate... cool guy. I saw no races that nite and they made about 3 or 4 random stops in the short time I was there... damnit there are too many cops now! hehehe Oh well do you ever go to Qualcomm??? Let me know I usually go. Later
 

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Discussion Starter · #7 ·
that sucks man! I got one last year for no plates. the cop was cool though. I thought they'd hassle me and make me open my hood but all they did was admire my car and explained the no plate law. it only cost me $10 to get it cleared. I haven't gone to the Q yet. The only ones I've been too was at the Sports arena. Hey let me know when the next meet is at the Q. We'll hook up over there.

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Ray
1998 Eclipse GST
Mods: 3" Thermal R&D, Greddy TypeS bov, dump tube removal, MBC, Sprint Lowering springs, strut bars, Autometer gauges, HKS timer, custom interior, 17" performance rims

 

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I would think that the bov would be louder with the spring set to a stiffer setting. With the spring set stiff it hold all of the venting air longer and then I would think it would let it out under more pressure hence louder than the soft setting. I am using a 1g BOV so I don't have any hands on experience though.
 

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Hey guys,
I'm not sure if that would be the case. For example, you have a BOV on a hard setting and one on a soft setting that are both able to hold a certain boost level. When you close the throttle plate and the sudden drop in reference pressure activates the BOVs, the BOV on the soft setting will be able to open bigger and thus relieve more pressure faster, hence creating a louder sound. Thus the BOVs need to be setup so that they are at as soft a setting as possible for the current boost level to be at their most effective.
 

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Discussion Starter · #10 ·
Jehu,

but do you know why the car feel more sluggish (especially on the higher rpms - top end?) when the setting is soft?

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Ray
1998 Eclipse GST
Mods: 3" Thermal R&D, Greddy TypeS bov, Greddy IC Piping, Magnecores, dump tube removal, MBC, Sprint Lowering springs, strut bars, Autometer gauges, HKS timer, custom interior, 17" performance rims

 

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Hmm...Intuitively, I'd have to say that you must be leaking air through the BOV at the softer settings, leading to an overly rich mixture. Do you have an AF gauge? Try to hook up a digital voltmeter to your O2 lines and you should see if you're getting too rich, and if the BOV setting is the only thing that changes, you're probably leaking. Did you connect the lower nipple on the Greddy? Not having one myself makes it hard to verify this, but I've heard that if you hook up the lower nipple to a different boost pressure level you can delay leakage, or something to that effect. Worth looking into.
 

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Discussion Starter · #12 ·
so what does the lower nipple exactly do and where does it hook up to? I've never hooked up the lower nipple to anything. maybe thats where my leak is???

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Ray
1998 Eclipse GST
Mods: 3" Thermal R&D, Greddy TypeS bov, Greddy IC Piping, Magnecores, dump tube removal, MBC, Sprint Lowering springs, strut bars, Autometer gauges, HKS timer, custom interior, 17" performance rims

 
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