No more lag ?

[burldude]

From what I have seen the biggest restriction in the intake and the exhaust is the turbo . What if a person was to make a flapper valve so that Within the first 4000 rpm the intake would bypass the turbo . And as soon as enough exhaust caused the turbo to develope boost the flapper valve would close having the intake charge directed through the turbo again . I would think that this would only be benificial on a huge turbo making peak power around 10,000 rpm. All of the intake air would be monitored by mas, nothing unmetered. Fuel trims could be adjusted with aem ems to compensate for the Na affect before boost.

Feel free to flame but I think that this would work well

 

[91turboTSi]

When racing, when are you ever going to be below 4000 rpm?

 

[burldude]

It is not just about racing, its about driving every day . Lag with a large turbo on the street is not cool . Turning a 10,000 peak turbo into a streetable turbo is what Iam talking about .

 

[Mirage2LTurbo]

Good luck with that.

 

[LightningGSX]

You can adjust your BOV to open at idle/low throttle, which will bypass the turbo.If you have a stock BOV, it more than likely does this already, hence the name "Compressor Bypass Valve".

 

[Defiant]

What you'd want is a simple check valve between the turbo intake and the throttle body. It'd be a nuisance to fit in there, and I don't know what is or isn't available out there.

But I fall back on the usual story: if it was worth it, you'd see lots of people doing it. I've not heard of any.

 

[kpt4321]

You're worried about lag, why the hell would you want to disable the turbo below 4000 rpm?

 

[djpast]

you ever driven one of our cars with a blown turbo.... hmmm 450cc injectors + low compression pistons = a rich running SLOW ass car. thats basically your ideal would be like.

 

[thekellbeast]

Lag isn't going to be solved by bypassing the turbo. You might have slightly quicker throttle response, but that will change the amount of lag a very small amount. Lag is the time it takes for the turbo to spool, not for the engine to pull air from the filter to the ports.

 

[autronicDSM]

Wow, you're on a roll dude! First, titanium engine and now lag free huge turbo. Amazing.

 

[butters]

Why not just use NOS to spool up quicker? I would think that would be an esier way of dealing with the lag on a large turbo.

 

[n3gativerr0r]

This wouldnt accomplish anything

 

[Mirage2LTurbo]

You can adjust your BOV to open at idle/low throttle, which will bypass the turbo.If you have a stock BOV, it more than likely does this already, hence the name "Compressor Bypass Valve".

My Tial 50 opens at idle, you can see it

Yeah, I'm with the above poster on this. This guy is really going to revolutionize the way we build our DSM's. I should have waited to build mine till after this guy got on here, it might be fastAr (or maybe just have more stickers).

 

[Zenja]

I think what he means is that when the turbo isn't making the boost, it's only being a restriction in the intake/exhaust. If you were to bypass the turbo at low RPMs you would eliminate a restriction, then once the RPMs are high enough to actually have a hope of starting to spool the turbo, route the air through it.

 

[herostar]

You can adjust your BOV to open at idle/low throttle, which will bypass the turbo.If you have a stock BOV, it more than likely does this already, hence the name "Compressor Bypass Valve".

The reason for a Blow Off Valve is not only to regulate boost, but also prevent compressor surge. It's called a Compressor Bypass Valve because the compressed air bypasses the turbo when it's released from the intake tract.

 

[kpt4321]

I think what he means is that when the turbo isn't making the boost, it's only being a restriction in the intake/exhaust. If you were to bypass the turbo at low RPMs you would eliminate a restriction, then once the RPMs are high enough to actually have a hope of starting to spool the turbo, route the air through it.

Sure, but who really cares about the restriction of the turbo at 2000 rpm? If you really need power that badly, rev higher.

It's just a LOT of weight and complexity.

 

[kpt4321]

The reason for a Blow Off Valve is not only to regulate boost, but also prevent compressor surge. It's called a Compressor Bypass Valve because the compressed air bypasses the turbo when it's released from the intake tract.

I am sure that LightningGSX knows that, and I don't quite understand what this has to do with the topic. The open BOV he suggested will help elimiate the restriction of the turbo....

 

[herostar]

The way it was used in the post I quoted was not very correct. It made it seem like the BOV was there to act as a bypass for intake air INTO the engine, when it is actually a bypass for air to LEAVE the intake track. I just posted as a clarification, because I thought some people might be confused by the post.


In regards to teh original post... I agree with others... if a bypass really did help, people would be using it, and cars would probably come stock with some sort of bypass. Someone correct me if I'm wrong, but don't some roots-type blowers use a bypass like this for idling?

 

[Mirage2LTurbo]

I am sure that LightningGSX knows that, and I don't quite understand what this has to do with the topic. The open BOV he suggested will help elimiate the restriction of the turbo....

It wouldn't be too hard to accomplish, just make sure to vent the BOV back behind the MAF, and put a solenoid inbetween the bov and the boost reference.

 

[n3gativerr0r]

A 10,000rpm peak power turbo with no street manners isnt gonna restrict your airflow much if at all from idle to 4k rpm anyway. If you got it to work Id be suprised if you even picked up 2rwhp of low end.


Burl you obviously have a rampant imagination, and some creativity. And Im sure you put what you think is alot of good thought into these ideas before you post. But you really need to learn more about complication:efficiency. All these ideas are either not worth the time and money, physically unfeasible, just plain stupid, but usually a combination of the 3.

Again work on making a fast car first the proven way, then if it was 2 easy go about trying to make power the round about, pita, impossible way you seem to like so much.

 

[LightningGSX]

The way it was used in the post I quoted was not very correct. It made it seem like the BOV was there to act as a bypass for intake air INTO the engine, when it is actually a bypass for air to LEAVE the intake track. I just posted as a clarification, because I thought some people might be confused by the post.


In regards to teh original post... I agree with others... if a bypass really did help, people would be using it, and cars would probably come stock with some sort of bypass. Someone correct me if I'm wrong, but don't some roots-type blowers use a bypass like this for idling?

Obviously BOVs vent boost when the throttle plate closes to prevent surge, most factory BOVs are designed to open at idle to bypass air INTO the engine as well.It makes for a better off idle throttle response, this is also the cause of most of the problems with venting to the atmosphere.

Not to long ago I did some experimentation with an electromagnetic BOV, I made it close when the boost crossed the 0 psi threshold, and open again when the throttle plate closed with greater than 5 psi boost.I doubt there were any power gains, and I didn't notice any decrease in spool time, but off boost throttle response was very noticeably improved.

 

[LightningGSX]

It wouldn't be too hard to accomplish, just make sure to vent the BOV back behind the MAF, and put a solenoid inbetween the bov and the boost reference.

Why? The vented or bypassed air is already metered.

 

[Mirage2LTurbo]

Why? The vented or bypassed air is already metered.

Because it's going to run like poo on a mass air metered car if you're venting off air to the atm. Recirc it back between the MAF and turbo, and it would work.. in theory.

 

[LightningGSX]

Since atmospheric venting wasn't mentioned, I thought we were talking about a recirc BOV setup?

 

[Mirage2LTurbo]

Since atmospheric venting wasn't mentioned, I thought we were talking about a recirc BOV setup?

We are, as stated in my third post.