I for one would be very interested in this thread.

 

My measurements, reported elsewhere, bear directly on Don's claim. I measure about +10-20F due to the VGS and DT-BPV together. Which is responsible is arguable I suppose, but I undid the VGS and the temps dropped, still had the DT-BPV in the system. Haven't measured temps without the BPV mod, though.
Others with both, or each, mod report some varying results, especially inimmini, who has the VGS (don't know if he has the BPV).
I don't know if Don has posted his measurements, but I know he's taken them, and I believe him to be a very honest poster.
The reason for the temp rise is debated: since many have not reported any increase in boost, I doubt that's the reason. It could be inefficiency due to producing boost that's not needed by the engine and so dissipated as excess heat.
Or not

 

Anyone have any numbers specific to stock IATs vs. DT BPV IATs?

"Increase IAT" could mean 40F or 2F.

And, would an '06 benefit from this. My car is a little rough, specifically around 2300-3k rpm. I'm not sure if it is the infamous yoyo or not, but anyone know if the DT BPV would smooth out an '06?

I know that intake port design cause a bit of stumble and can only really be dealt with via head work, but a small improvement in smoothness would be appreciated for a low cost ie DT BPV.

 

I talked with Chad a bit on Saturday about putting a DT BPV on my 2006. He said it would give me better throttle response & maybe an additional pound of boost. He said the stock BPV isn't a very good piece. I guess a good description of his would be a blue printed one with a stronger spring. I am thinking very hard about buying one.

I hope Chad sees this post & chimes in.

 

The reason I do not give any specific number is because the IAT increase varies with respect to the ambient temperature and the intercooler in use.
In addition to higher IATs you also loose throttle feel/modulation. Thus, the way I see it, it will not give any performance benefit.

 

All due respect, I didn't ask for reasons why you don't post numbers, I asked if anyone had numbers. And we are talking deltas. Obviously ambient temps will have an effect on IATs.

I'd like to see the IAT for a stock car vs IAT for a DT BPV car. Everything else being equal.

I have no problem with your opinions dmh, I just want to see something backed up. When the vast majority of the community says that it will improve throttle response and that previous testing has proven that DT BPV may not raise IATs all that much, it would just nice to see some data to back up opinion.

 

Well, there you go: "the vast majority of the community says that it will improve throttle response and that previous testing has proven that DT BPV may not raise IATs all that much." It must be good then!

 

The DT BPV valve w/VGS mod does, in fact, increase IAT.
Some have lower IATs than others with both mods over a large range of ambient temps. These temps are still quite high.
See post 27 DrPhil has done a ton of homework on the subject.

On this car the VGS mod has had no effect on IAT. The spring in the OE unit, on this car, is quite weak and can be fooled into never closing if you gradualy accelerate. In this case the DT BPV would be a good mod. Almost every early car, 02 - early 04, that I'v seen, have had some benifit form this mod. I can't say I know anyone that has done more than the VGS mod on a late car. This does not always solve "Yo Yo"( I'm waiting for a friend to put 1 on his late 06 w/ "Yo Yo").

Bottom line, you do 1 or the other but not both. This would be the preferred method. I believe the VGS was first, could be wrong, and was not likely intended to be used in combonation with the DT valve. As far as the DT BPV being a good mod, the jury will be out a long time. It works for me & I'd recomend it someone with an OE unit like mine but I'v seen more than one removed & returned to OE. It, most certainly, is not a universal fits all.

 

I think that would be a great post!!!!!!!!!!!!!!!!!!!!!

 

DMH you state that you measure IAT and the DT valve will increases it but then you say that you don't have specific numbers. Then when someone questions you you shoot out a wise remark.

Yes please post your wisdom on all the other poorly thought out modifications.

"Well, there you go: "the vast majority of the community says that it will improve throttle response and that previous testing has proven that DT BPV may not raise IATs all that much." It must be good then!"

 

Don can speak for himself on this one, but I am happy to share with you my experiences from 3-odd months of logging IC and general intake air temperatures. My many posts contain dozens of temperature readings, and I have both the VGS and the DT-BPV since my '05 has very bad YoYo. These mods mollified the negative effects very well, but at the price of higher temps, especially out of the SC. I have reported approaches (formally the difference between ambient and intake manifold temps) of less than 10F to as high as 60F (lowest on cold, constant highway runs, and highest in "I've been in this traffic jam way too long and I need to press the skinny pedal" scenarios.)
On to my point here: doing all this measuring has revealed to me that intake temperatures vary considerably--in statistical terms they have a very high variance/standard deviation. I'd compare them to stock prices of a company with a beta of 4.0!! Consequently I am interpreting Don's reticence to post numbers as reflective of his understanding of this large variance in the measurements of the various parameters related to intake performance(remember, Don was a futures/options trader in a previous life, so he understands all this.)
Anyway, I'm all for cutting Don some slack--he is pretty savvy when it comes to MCS performance.

I'm out

 

DHM I am not debating the mod or the affect it has on the temps. I am sure that it does affect the temp in some way.

There is just a better way to get your point across.

 

Are you speaking to me? Otherwise, you should quote, or indicate to whom you are referring.

 

DrPhilGandi the post was not directed at you at all.

I will edit my post.

 

Our BPV works a lot like stock, but has a stronger spring designed to work better than the stock spring. While I have the new valve I readjust the butterfly. If you're sitting at a light on a summer day in a car without our valve, your BPV is open and recycling most of the boost your supercharger is making. You're drawing in the air from outside at whatever temp it is. The supercharger then heats it, and the air then goes back through the intercooler. Since you're sitting at the light, your intercooler is getting heat soak from air in the intake path and heat coming off the engine. It takes a few seconds after you start driving to cool things off. A car with our valve, is now only recycling part of the boost.

The yo-yo is normally found under speed, around the 3k area, 4th gear, but can be found on some cars in all gears, and at other speeds. The yo-yo is produced when the BPV opens and closes rapidly bringing the car on and off boost. If you have a boost gauge, you can watch it. We added a stiffer spring to overcome the problem of the valve opening under speed. We have also found most valves tend to open too far, and each car is different. To correct this, we readjust the butterfly to close completely. This makes all the boost that your supercharger is making go directly into the engine. Most cars see 1 more PSI of boost on gauges and dyno runs. Our BPV also gives a better throttle response because of the extra boost. It is not a drastic change, similar to changing from a 15% pulley to a 19% pulley. You're now making more boost down low so the car feels much faster.

I get a lot of questions asking if this mod is good for an '05-'06 car...etc. This mod is for anyone that wants to get the most out of their car. If you do not have the yo-yo, it may be worth it to add to make sure you're getting all the boost you can. Each car is different, so the effects on each car are different.

It will affect intake temps a bit, but not much. Adding a 15% pulley adds a whole lot more intake temp than our BPV, but it is the most bang for the buck. I measure a lot of intake temps while I am driving customers cars. Today I drove a car with a stock pulley, with just an Alta intake and cat back exhaust. His intake temps where higher than my car without BPV, a 15% and 2%. Both cars have the stock intercooler, but mine has a custom air diverter to force all the air coming in through the intercooler. I forget the numbers, but it was around 15 degrees or so.

As for VGS, I never recommend this mod with our system, but some people still choose run it.

If anyone has any questions, I am always around.

Thanks
Chad
Detroit Tuned

 

If you are going to quote someone, don't take what they said out of context.

What I was trying to say was that we have this whole group of people who say that the DT BPV improves throttle response, and you say it doesn't. I was just looking for some data. I was merely seeking information, not trying to take shots at anyone.

The point is moot now anyway.

Just don't quote out of context.

 

People pay me to make their cars perform. To do so, I have to know the cars I am working on -- Porsche, BMW, and Mini. And that means testing at road race tracks. It doesn't matter to me what non-customers bolt on their cars -- I am simply trying to bring information to the NAM community. Unfortunately, this is turning out like many other threads in which irrationality becomes the rule and when that happens I leave it.
I have posted numerous times why I do not post my data; basically, it is data for my use and if it got out it could get applied improperly. All you have to do is reference the dyno numbers posted on the site to get the idea of what I am talking about. Until it becomes understood what dynos are for and how to control the variables the numbers are invalid. And Dr. Phil is correct; I understand statistics at a highly sophisticated level.
With respect to the DT bypass valve and Chad, I don't really have much to say other than you absolutely loose throttle modulation. How do I know? I bought one and tested it. It’s definitional -- the valve acts as a light switch with the stiffer spring. Install one and then try to feather the throttle through a long sweeper and you’ll understand. For those in LA, think turn 9 at Willow Springs. It also increases IATs without question; especially in summer -- the time of year you need the lowest IAT possible.

 

Don,

Just trying to learn more info as other here are I am sure. I think we value your input and thus all the questions come pouring in when you state something about a product.

So, hopefully you can answer one last question before you leave the thread.

If the DT BPV does give 1 additional pound of boost, does this help offset the higher IAT's? I guess that they may negate eachother then?

Thank you,
John

 

I have never seen the stated additional boost and I also don't understand how a stiffer could produce additional boost -- the s/c makes the boost. If the butterfly is adjusted correctly and there are no leaks then all should be good.

 

Thanks DMH! I like to go fast as much as the next guy but the more you get away from the R&D BMW did to produce the Mini I think you’ll regret the outcome…The more I read this post and other like it, I realize the aftermarket manufactures are really trying to produce quality products to help increase the performance of your car. But, at the end of the day, their number one priority is to make a profit. Caveat emperor…

 

Beware the Ides of March, also!! I love this, especially as an economist, for whom the latin is more usually caveat emptor.
Sweat! Thanks for the grins.

 

There are few if any things that one needs to improve the Mini if compared with everything else in its class & what class would that be?

But we all want to try!

 

part of the reason that cars see more boost is because we do readjust the butterfly. one step we take is to make sure the butterfly is centered in the bore. i used to see this all the time, but not as much anymore, but i always check. the second step we take is to make sure the butterfly closes fully. every valve i get it's open too far. several that i have seen have been very open, where the minis have gotten more than 1 PSI of boost. but most are just open a bit. so by closing the gap, you are now sending all boost from the S/C to the motor. so that adds boost. then the stiff spring closes the valve sooner and faster, giving the car more time to make boost in the rpm band. all of this helps make HP

in the end, i have this item on my own car. if i didn't think it was worth selling, i wouldn't, nor would i have it on my car. i have sold a lot of them all over the world, and so far everyone has been happy. but mods, what ever mod it is, is not for everyone. i know lots of people that still think the 15% pulleys are still going to blow up their cars, but i think everyone has proven it is a good safe mod. hope that help explains things a bit better.

 

Before dmh was around on this forum, I designed the DT BPV as a solution to dampen the Yo-Yo drivability problem that was plaguing most 2004 MCS's. I fully understand the DT BPV, because I designed it.

dmh has left out a critical piece of information regarding IAT's; they're identical to the stock BPV under WOT, when it really matters. The temps are the same because both the stock BPV and the DT BPV are both closed fully over 0 inHg. Once you're in-boost, the BPV's are functionally the same. The main improvements with the DT BPV are part-throttle is smoother [in vacuum] drivability and the transition into boost quicker.

Cheers,
Ryan

 

Thanks for filling us in Chad. Do you feel that throttle response is improved with the DT BPV? What are the benefits of putting one on a 2005 or 2006?