Is there a "known" spring to replace the factory one with for more performance?
Would this be better than just the stretch?
If so, where would one locate this?

thank you!

-jac

 

put my dtbv on today . tried the cold throttle right after.... it sucked . i couldn't believe it . i ran propane over every hose and fitting i could find and no leaks. so i let it warm up and went for a ride. it sucked. big flat spot then boost . the boost was awsome but the drivability well you know ...it sucked. so i took it home and called dt to make sure my GIAC wouldn't be lost with a reset. then i did a reset . it's much better already.

 

the first "DTBPVs" were made by hand by Ryephile. He and chad thought about started to launch DT, but the partnership didn't work out. Anyway, Ryan is the guy who started winding them by hand, and I don't know if he ever "spec'ed" a spring. but if they did give this little piece of magic out, then anyone could make their valve for very little money.

So no standard spring....

Matt

 

I installed a DTBPV about a month (and 5K miles) or so, ago, in an effort to help the flat spot/surging/yo-yo around 3K RPM. This was DT's suggestion as to how to address the issue.

Unfortunately, it makes zero difference on my car - numerous ECU resets done, just in case.

I'd take it off and put the stock one back on, if it wasn't such a PITA.

YMMV.

 

looks like the v2 header from mini-madness is in my near furture. moneys just for paddin you *** from potholes anyways!

 

has anyone bypassed the bypass? i mean just as an experiment to see if the flat spot is worse when relying on all air to come from s/c only.i'm thinkin' it would be worse. the bypass valve though smaller in diam. seems to offer a much quicker route for the air . so off idle would be better to have a weaker spring thereby the bypass is open further. i doubt my compression is that bad as to not have enough vacuom to open the stocker but maybe the stonger spring is too much for the vacuum i'm making?

 

i'm thinkin' there's got to be someone who can make a solenoid operated bypass to dial in the opening according to exactly the amount of vacuum being produced and not just a this spring or that spring deal.

 

I lined up against an SRT-4 on a long straightaway(not on a public road of course) while loaded up with roughly 300lbs of extra gear. From 60-120 I took him by a couple car lengths. I do have a few modifications and JCW though so its not exactly a valid test.

 

then a spring diaphram is pretty good. If you want to do more variables, then some electronic control might be nice. Sure you could do all that, but would you really pay $400 for a computer controlled by-pass valve when there are so many other things to buy?

Matt

 

well the whole flat spot thing could be sorced right here and not at the ports at all .like i said earlier; my flat spot was next to nil before but huge after the dtbv. it is getting better after the reset but it makes me wonder if the transition to boost from bypass is the issue giving us flat spots. everyones car seems fine at or near full boost. maybe more air lower down like a bigger bypass circuit?

 

that really made it show up. But I think it's more insidious than that. As you push the car farther and farther into mod land, this flat spot becomes worse and worse. Lots of things make it worse. Now, for insance, I can go back to a stock TB and I still have the flat spot. So I'm finding I agree with the premise that it's in the design of the head/intake ports/exhaust ports thing and that lots of items can change the symptom, but the cause is still there.

Since the BPV, TB and the like are all involved in the drive by wire system, pretty much anything that affects that has been known to make the flat spot better or worse. Sad thing is we don't have a well enough compiled body of empirical evidence to know what combo of parts minimizes the effect.

Matt

ps, for me, going from a stock to modded valve makes no difference!

 

No solution, just some FYI, I’ve had more than a few misbehaving BPVs; one failed stuck open which the dealership kept. Both times the dealership replaced the BPV they broke more things than they fixed so I did the rest myself in self defense. In my experience butterfly binding was the most common cause of the flat spot. It may feel great to adjust it fully closed but in the long run I had better luck with centering the butterfly plate and leaving a gap light could shine through. BTW, I prefer the weak stock spring for better gas mileage. FWIW, with clean injectors, new air filter, new plugs, fresh oil & filter, clean intercooler, and a fresh BPV, on top of number of motor mods and port optimization, no flat spot; for a while at least.

The BPV has changed configuration three times; the latest version has a little more casting reinforcement around the shaft near the stop limiter. I would assume that is in response to some cracked casings that seem to be associated with the “stuck” syndrome. It wasn’t long after the first version, the butterfly plate fasteners were flare staked; evidently some had worked their way out.

 

I did the DT bypass valve and am happy that I did. Better performance and it moved that awful CAI whistle away from the highway crusing throttle opening.......................BUT I am one who, despite my best efforts, broke the little plastic tab on the intake tube. This caused me to spend another $60 on a new part and take the front bumper off to install it. I still think it was worth it!

BTW, Chad at DT is the best and even returned a call on Sunday of a holiday weekend! Now THAT's service!

 

Putting the car into service mode (front end off) is a good thing to learn, there's so much that you can get to if you do it. don't think of it as wasting $60, think of it as a very cheap lesson!

Matt

 

took it out again today ;it's getting better my ecu must've rode the short bus .... now that you mention it the whistle i hated is gooooooone!

 

ooh oh mister cotter!!! the whistle was the space not sealing on my old bpv? there was a gang of light around that bad boy .

 

Is it just the spring not closing it all the way? or can the valve actually be adjusted to fully close?
There must be a thread on this somewhere here, just feeling lazy today.
I have this whistle as well and would like to get rid of it.

 

I have been told that the whistle that shows up with the addition of a CAI is from the throttle body, not the bypass. I'm not sure, but I do know that both my old bypass and my Detriot Tuned bypass close fully and in both cases I have the whistle. The DT bypass has changed the throttle opening where the whistle occurs to a less annoying spot.

Just my .02, your mileage may vary...

 

you can adjust your old valveto close fully and with manipulation of the butterfly you can get it to seal fully (loosen screws and adjust). if the new one doesn't stop giving me this more pronounced flat spot ,i'm going back to the old one with the weaker spring ,i'll just adjust the butterfly for a better seal . i'll keep detroits for a spare.

 

ever notice it's right at the transition to real boost?

 

It seems that way now, certainly further into making boost than it was. With the original bypass valve it was just at a very light throttle, the kind of throttle setting used to maintain speed on the highway; it drove me mad.

Funny thing, the VGS mod almost entirely eliminates it. I've talked about this with a few experts, including Eric at Helix, and they all say it's the throttle body not the bypass.

 

but the interaction of the by-pass valve and the drive by wire system effect what throttle opening and RPM this happens at.

Matt

 

bingo!!!! i was thinking on this on the way home. my cold starts since the detroit are way worse; so i'm either not making enough vacuum and need to do a leak down or my fuel pressur is not high enough . the latter is probably not the issue as with the stronger spring i should be getting less air at idle .assuming vacuum is too weak to fully open the detroit.unless it's a pressure deal ; assuming the detroit were closing sooner the s/c is adding man. pressure sooner . my tps is arguing with the map sensor and the tps wins causing a lean surge(yo=yo) ala flat spot.

 

it certainly feels like a lean surge and funny thing is i never had it before it's like it's making too much man. pressure for the throttle pos. i'm thinkin' the bypass diffused some of the pressure. anyone seen lean cond. on af meter at this rpm?

 

put the stocker back on today adjusted it though to seal fully but not to stick. car is kick a$$ again. flat spot is hardly there just a blip on the radar. boost is better due to seal. i'd say in my case anyway ;the sooner boost doesn't work. so hey it wasn't a waste i have a spare and learned some stuff.