Recirculating turbos anyone?

[Nick675]

So I've been thinking a lot lately about recirculating boost instead of dumping into the atmosphere ala Porsche 997 Turbo. With all the turbo NSX's running around I was wondering if anyone had thought about it at all?

And no I don't mean from BOV into exhaust out stream. I am talking about reusing that created boost to recirculate back to turbo mainly for the following reasons:

• To reduce the noise caused by compressor surge on throttle closure
• To speed-up turbo response following gearchanges
• To reduce airflow metering problems caused by reverse flow back through the airflow meter on throttle closure

 

[ac3320]

So I've been thinking a lot lately about recirculating boost instead of dumping into the atmosphere ala Porsche 997 Turbo. With all the turbo NSX's running around I was wondering if anyone had thought about it at all?

And no I don't mean from BOV into exhaust out stream. I am talking about reusing that created boost to recirculate back to turbo mainly for the following reasons:

• To reduce the noise caused by compressor surge on throttle closure
• To speed-up turbo response following gearchanges
• To reduce airflow metering problems caused by reverse flow back through the airflow meter on throttle closure

I have wondered the same thing. The whole *WOOSH* BOV sound is kinda ricer IMO, especially in light of the NSX's prestige in the automotive community. I guess it has it's place in the S2000 scene, but even then...

Plus, as you've mentioned, the 997 turbo, 335i, R35 GTR and many other twin turbo OEM setups use recirculation. SOS offers a twin turbo setup that has the potential to be a reciruclating setup. Sounds pretty sweet to me..

 

[Juice]

LoveFab created a setup with compound turbos and had some nice gains, but it was prohibitively expensive. Beyond that, I doubt it is really worth it. Creating large HP or TQ numbers is the easy part; keeping the drive train together is the real challenge.

Frankly, I'm ready to polish off my ricer side and hear that pfft-whoosh sound for a while. As long as I can back it up, everyone else can eat it. :wink:

 

[Myaddiction]

So I've been thinking a lot lately about recirculating boost instead of dumping into the atmosphere ala Porsche 997 Turbo. With all the turbo NSX's running around I was wondering if anyone had thought about it at all?

And no I don't mean from BOV into exhaust out stream. I am talking about reusing that created boost to recirculate back to turbo mainly for the following reasons:

• To reduce the noise caused by compressor surge on throttle closure
• To speed-up turbo response following gearchanges
• To reduce airflow metering problems caused by reverse flow back through the airflow meter on throttle closure

Our cars use manifold pressure sensors not MAF's so the last item is a non issue. The second one is marginal at best. I assure you can not tell the differnce if any there is in the spool up by recir'ing the BOV. If there is extra pressure it will just go out the air filter before it speeds up the compressor (path of least resistance)

So really your left with the first item on your list. Which is why factory turbo cars come with recir valves. Just a personal choice really.

 

[E-Nough Logic]

Our cars use manifold pressure sensors not MAF's so the last item is a non issue. The second one is marginal at best. I assure you can not tell the differnce if any there is in the spool up by recir'ing the BOV. If there is extra pressure it will just go out the air filter before it speeds up the compressor (path of least resistance)

So really your left with the first item on your list. Which is why factory turbo cars come with recir valves. Just a personal choice really.

read my mind. recirculating the BOV on the NSX would be a waste of money unless you want to reduce the sound. your best bet would be to get a suttle BOV. IMO the tial 50mm BOV's arent very loud and dont have that "ricey" sound.

 

[sca037]

I for one would miss the whoosh sound (assuming the baffle is in so it can even be heard ;^)

Brian

 

[CL65 Captain]

I am right there with you. If I went turbo it would have to have both a recirculation valve and the wastgate plumbed back into the exhaust. I believe that the Sos twin kit allows for both options.

I have never seen an oem run open wastegate so why would I?

 

[ScienceofSpeed]

Our twin turbo system offers the customer to choose between a TIAL vent to atmosphere blow off valve or twin Bosch recirculating valves. The choice between the two is almost completely a preference based on sound. As noted above the atmosphere vented makes more noise than the recirculating, but the TIAL is a fairly quiet valve. If you will be at NSXPO, we will have three twin turbo cars there, and one has the recirculating valves.

cheers,
-- Chris

 

[01blacks4]

Well the difference between the BOSCH unit and a TIAL style unit really is a silly comparison as the BOSHE unit is not being used as designed on the nsx.
It is meant to recycle the boost pressure into the airstream, pre-turbo, pre-throttle body effectively eliminating ALL venting to the outside. This eliminates all whooshing sound.
Venting this BOSCH to the atmosphere as SOS and others are doing limits the sound primarily because of size….the TIAL is a 50mm opening while the BOSCH is about ½ that
they are really not recirculating anything...

 

[CL65 Captain]

Venting this BOSCH to the atmosphere as SOS and others are doing limits the sound primarily because of size….the TIAL is a 50mm opening while the BOSCH is about ½ that
they are really not recirculating anything...

Chris, is this true? The SOS Bosch recirc is not being used to actually recirc?

 

[01blacks4]

Chris, is this true? The SOS Bosch recirc is not being used to actually recirc?

i think he uses one on the SC? which may reci.
i dont think he is on the turbo....

i could very well be mistaken...

the biggest issue is that a REC system is sorta meant for a MAF system while the NSX is a MAP system

 

[e.pie]

These turbos look like they would be right up your alley.

http://www.motoiq.com/magazine_arti...id/1750/borgwarner-efr-turbo-feature-set.aspx

 

[Myaddiction]

I have never seen an oem run open wastegate so why would I?

Mainly because you don't have to meet the emmission and noise requirements that OEM does.

It's worth quite a few hp to dump the wastegate instead of merging it back into the exhaust. When I had a 350Z with the Greddy twin turbo kit at 8psi it freed up nearly 30 rwhp to change it to being a open system instead of merging it. No turbo race car puts it back in the exhaust unless the regulations require it for noise considerations.