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CBV Recirculation on SD

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EVLGSX

5+ Year Contributor
655
253
Dec 7, 2017
Wallingford, Connecticut
Ive been doing whatever I can to get the most out of an evoIII 16g setup. I recently picked up what I will be needing to recirculate the bypass valve. Id like to hear about anyone else's experience out there that has experimented with this on Speed Density, and would like to know if it was worth the effort. I do not care what it sounds like, I am only after performance gains, and am hoping for a small improvement in transient response, at best.


Here's a pic for reference, I'm going to clock the valve outlet more towards the compressor cover, rather than towards the passenger side as it is now, and then weld my piece of 1.25 pipe angled in , just after the 4'' coupler on the intake pipe, as most would expect.

Id also like to eventually come up with a cone that tapers from 4'' down to 2.25"........over like a 5-6'' span, to ease the transition. I really dont like that awful 4'' to 2.25 coupler at the turbo. I guess that would be another topic, along with weather or not a 4'' pipe even has any business on this setup. I have/tried a 3'' pipe, one of those Injen cast units, and an FP cast unit.

Thanks for any input guys.

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Never saw it originally myself otherwise I may have weighed in.
I think you're on the right track, should help with transient by equalizing the pressure differential between inlet and outlet, reducing compressor wheel drag between on/off boost. But I'm not smart enough to run through the math.
I experimented with intakes on my 14b some, but didn't notice much change, probably due to it's small size, it already spools isntantly under load. I had a 6" section tapered like you stated, made from a center cut, crimped together and rewelded 90* piece of pipe, then hooked to my bumper corner intake. It was 3" I/C pipe and ugly on the outside, and if it had cleared a few things better I'd have kept it, but I could route the non-tapered piece better with what I had and I haven't noticed a major change in performance.
Once again, all on the 14b and a 1g so not a direct comparison. Unfortunately I do that have the tapered intake piece as I scrapped it.

Maybe it's the lack of big gains on the bolt on turbos that lead ppl to go with the standard intakes available.
 
I to have always wondered about this, to me the sound is not as important as efficiency. I'll be watching to see if anybody with actual numbers or incite would chime in. I'm with ThunderChild that it should in theory help some but I'd say not a lot.

Just trying to visualize the flow, I'd say it would have to be somewhat close to the turbo to see any benefit. But not to close as to not disrupt the intake flow any. I'd say its all negligible but I've always dreamed of a perfect flow motor. LOL Do we have a flow engineer on this site?
 
Well Im going to try and get to it at some point soon and will share my impressions on whether it was worth the bit of effort or not.

The 4'' pipe is just a cheap piece I bought and cut to make work.........which worked out really good for 30 bucks. Ive got no issues doing whatever with it, and just making up a new one down the road if it doesnt fit in with whatever I end up doing.

I plan to have the bov firing in pretty close to the turbos inlet.

The way it is now seems like a waste..... and its why I bought THAT valve when I did, instead of the one everyone seems to buy, which dumps in all directions.
 
If a compressor wheel is spinning at 100k rpm or more, and exhaust gas velocity suddenly slows (as in on a shift), I ponder what a momentary blast of turbulent air, of significant volume, at the compressor blades does for tip velocity and thrust loads..
a 14b on 1.25" or less charge pipe at 11psi is one thing.. 38lb/min may be another.
I am not drawing conclusions here, I am purely wondering what applying a setup meant for relatively small airflow numbers to a larger implementation will do. Perhaps nothing at all, perhaps beneficial, but also perhaps detrimental over time. shrug
 
We shall see. I do know the stock 2g has a recirc pipe inside the snorkel that dumps at the wheel. Of coarse this is on a stock 2g T25, so not apples to apples of coarse, but the effects apply on a smaller scale, and for some reason, I feel good knowing that.

A blast of turbulent air could be of detriment..........who knows, I am certainly not about to pretend I have a clue. I dont think Im going to worry about that for now though. Ive never heard to not recirc at higher airflow levels. This is one of the benefits of playing around with these cheaper turbos.......we can push them to the absolute limit...... and if it breaks....... it breaks. Ive got a few more. All part of the quest for more power.

At least were talking about this now! This was the kind of input I was hoping for when I created this thread. Thank you guys.
 
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Best thing I ever did for boost recovery after a shift was getting a tial q bov. The more air you can vent, the higher the shaft speed you’ll have during a shift.
 
So your saying the QR is not as good for boost recovery, and I would be better off with the Q and not doing what I mentioned above?


edit:
sorry- I guess thats almost impossible to answer unless you tried it but do your best haha
 
I've been wanting to put a tial with a recirc on my car for a while now. If you do yours please update us with how it works out.

will do-

interesting looking setup in your pic there..........I went to check it out in your profile, but it says not just anyone can do that...........whats up with that?
 
Was this really so stupid that I couldn't get a single response?? Bummer

I can not answer your question but I did have ask few things on this board and got totally nothing. You see if you would post that you are venting with a mass air flow sensor than your thread would skyrocket within minutes but when you ask something technical only select people with knowledge will answer and usually those people dont hang out on the forums all day long so a response is hard to get. Now that my smart a$$ post is over I wanted to let you know that your engine bay looks good.
 
will do-

interesting looking setup in your pic there..........I went to check it out in your profile, but it says not just anyone can do that...........whats up with that?

If my eyes are still seeing correctly than I think it is water to air intercooler. I might be wrong but that is what I think it is. Some new euro j..ks are going that way. Boost must be instant on that thing. I demend answers!
 
We shall see. I do know the stock 2g has a recirc pipe inside the snorkel that dumps at the wheel. Of coarse this is on a stock 2g T25, so not apples to apples of coarse, but the effects apply on a smaller scale, and for some reason, I feel good knowing that.

A blast of turbulent air could be of detriment..........who knows, I am certainly not about to pretend I have a clue. I dont think Im going to worry about that for now though. Ive never heard to not recirc at higher airflow levels. This is one of the benefits of playing around with these cheaper turbos.......we can push them to the absolute limit...... and if it breaks....... it breaks. Ive got a few more. All part of the quest for more power.

At least were talking about this now! This was the kind of input I was hoping for when I created this thread. Thank you guys.

I mean, in its most basic sense, it would be akin to the secondary in a compound setup seeing the primary's momentary compressed charge, I just don't know if there is any actual measurable positive gain when exhaust gas is no longer driving the turbine. Will it actually help spin the compressor any faster, or will it just slam into the blades and back up in the pre-turbo tract? Will the jumble of extra air at the inducer actually slow its spinning or cause it to basically stall and chop in a way similar to surge?
The 16g doesnt produce a whole lot more than a 14b at higher pressures, so I bet the real good measurable result would come from much bigger turbo, but I am curious of whatever results you get.
I would do a test but I run a bv50 and my only recirc capable bpv is a 1g and all mine leaked starting quite early even after dodge garage modded.
 
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