I've found plenty of threads stating that a recirculated wastegate kills power, but does anyone have any proof with actual dyno sheets other than stating the theory of why it could kill power? Have a recirc setup coming from JDL Auto Design and was just curious if anyone had some actual test results or numbers to prove.

Thanks,
Anthony

 

Do you know how a bov works?

 

A couple of things...

1. Are you referring to the wastegate (which is the flap on the turbo that regulates the turbos RPMs) or are you referring to the diverter valve (sometimes called a blow off valve) which sits on the upper intercooler pipe?

2. Realistically speaking, everything robs power.

Regarding the wastegate.

The turbo's turbine side is what your "O2 housing" is connected to, and that includes your wastegate's flap. They aren't separated as stock, but are instead funneled into the same pipe (your downpipe via the O2 housing). Since your wastegate is only open when the turbo is making full boost (not always) it can add a significant amount of heat, and turbulence to your exhaust flow, which of course, would rob power. That's why you're seeing such an increase in the number of people running an external O2 dump (and because fire), and people are suggesting significant gains in switching from an aftermarket recirculated O2 housing, to the dump style.

Regarding the diverter valve.

Venting it to the atmosphere on any car is extremely inefficient. Some cars require it to be vented to run properly (usually based on a tune), but most require it to be recirculated.

VTA would almost certainly rob power because you're taking air that has already been compressed, cooled, and sent towards your throttle body that is now getting wasted.

Anyway... hopefully that helps...

 

Lol

 

I have heard many good points be made on both sides of the argument. VTA supposedly keeps the turbine spinning faster so when you shift there is less lag when you're "gunning it". I have also heard the opposite of that is true. I have heard that recirculating is better too though because of the obvious points just made by propilot. I can tell you my experience swapping out my stock recirculating bov in my IX. It was the metal one so it was the good one not the plastic VIII one. Once I put the Tial bov on it felt to me like coming out of a shift I was getting thrown back into my seat with power instantly. That was not what I experienced with the stock bov. But again I'm sure there are good points to be made on both sides of this argument. My personal experience though, VTA is better.

 

The OP asked a simple question: "Does recirculating your wastegate rob power?"

He clearly stated wastegate not BOV or DV so why are we getting sidetracked.

While I merely have assumptions rather than data which is what you are looking for all I can add is that turbo cars do not like back pressure. By recirculating that exhaust gas back into the exhaust stream you are adding back pressure which theoretically should hurt power.

Now I know that back pressure does have its role and running too large of an exhaust could actually hurt hp and tq and yada yada yada but I will let others chime in on that.

Depending on your setup I woulds imagine that recirculating it could limit power but I would say it varies from setup to setup. As long as its recirculated in a proper location the power loss should be minimal at most.

 

You're talking specifically about the blow off valve.

A couple things there as well...

1. On the compressor side of the turbo, it doesn't care where the air comes from, it just has to be there.

2. A poorly routed recirculating "BOV" could easily cause a compressor stall, but turbochargers fins are so aggressive that this is very rare.

3. The ONE drawback from recirculating is that the air will be warmer than the ambient air (generalizing) and as such, not as dense.

Recirculating or VTA isn't going to cause your turbo to spool faster per se, both methods would be plenty capable of allowing the turbo to spool at an efficient rate if they're setup properly.

I'd wager the OP was discussing the wastegate dumping to the atmosphere though... so perhaps it'd be worth seeing what question they'd like answered before getting way off topic (mostly my bad haha).

 

If someone asked how to eat an apple this website would make a 10 page thread on why an orange is better. Guy clearly asked about the WASTEGATE.

At stock like boost the closed Wg seems to out perform the o2 dump. Also I remember a thread buschur did that stated he had a stack of flanges already Togo an canned the o2 dump because he found it did not make more power... And to this day they don't sell them.... But JOhnBradly seems to love them.... Hopefully we get more good info on this from some peoplewhohave used both..

 

Haha so true. Oh well evom is still the sh*t. I've learned so much from here through the years.

Back on topic I know exactly what you are referring to. I remember back probably ~5 years ago when external dumps for stock turbo setups were becoming popular. Im talking back when EPM and QTP were offering them. I remember reading exactly what you just stated where DB did not notice any gains from them. Now I know Dave is a no BS kinda guy but it was sorta interesting to see how he never liked them however there were other reputable guys who loved them.

Personally I had one in the past and I felt that the car was able to hold boost higher in the RPM's relative to my other setup. I ended up getting rid of it bc it was too loud which although sounded awesome, it attracted too much attention.

 

The reason I went the route I did was because the fellows posting right after mentioned BOVs. Sometimes it's just easier to over explain than deal with 45 posts of bull**** missing the point.

 

Sorry bud, I didnt mean to attack you or anyone really. I was just pointing out that the OP said wastegate so I didnt understand why folks were questioning if he/she was referring to a BOV/DV or wastegate since it was clearly stated

 

Oh no... I got you. Just didn't want people thinking I was more of an idiot than I am!

 

... I stated wastegate, and that's clearly what I meant. I currently am running a VTA wastegate and it just kills it for me every time it opens up so I'm going recirc. Thanks to those that added some useful information instead of assuming I meant the BOV.

Edit- I've read a hundred threads on the "theory" behind why it kills power but was curious if anyone had any factual proof of it other than theories and he said she said.

 

subscribed... although OP since you are going from a VTA wastegate to a recirc. maybe you would be able to show us if you lost or gained or no change happens.

 

watch this