A quick conversion, that is almost exact for garrett maps and seems to be really close all around is divide the Lbs/min by 0.069 for CFM. It will be close enough for an apples to apple cider comparison.

Oh and using that formula a GT4294 (which is a K31 with out the internal wastegate, which is what a A5K is with some modification) Moves ~85lbs/min which is ~1231cfm putting it under the r700 primary which is 71.1mm inducer vs the 70.3mm on the GT4294.

 

These are very close although I myself do not have the equipment to measure compressor flow.

04.5-07 He351cw 950 CFM
03-04 He341 ??? Guess between 800 and 850.
94-2002 HX35/40 Hybrid 6 blade 60mm 910 CFM
94-2002 HX35 800 CFM

 

I don't mean to pick apart the numbers provided because any number is better than no number.

r850 primary- 74.6mm - 1552 CFM seems a bit high, should be closer to 1425 CFM or 98.1 lbs/min.

 

So my stock holset on my 06 outperforms a super B?

 

I don't think so, I've had both on my truck and the Super B was night and day better than the stock turbo in every aspect. I have no charts to prove anything just experience from daily driving and towing 10,000lbs. It spooled faster, had higher boost, and was all around more fun to daily drive with. I know that the Super B gets kicked around some because of it's size but in my opinion it's better than stock, and for me it was a step towards twins.

 

IMO the Super B is a good turbo..but only due to the larger ex wheel and housing. Anytime you reduce DP, the engine becomes more efficient and always runs stronger.

 

If by outperforms you mean flows more air, then yes.

 

What is the super B special in terms of 64/71/14 and extended tips/blade mods are what? DOes it require the adapter/pipe elbow for the intercooler or does it have a 3rd gen housing?

 

It's true that pushing 35-45 psi boost with the Super B will result in more airflow than your stock HE351 pushes at 26-28 psi.

It's also true that a smaller compressor wheel will spoolup faster than a larger one.

It's also true that buying a super B is a step towards BD's towing twins setup.



What you failed to realize was the potential of your stock turbo with a few inexpensive modifications.
1. Add a wastegate controller or splice in one of those 20 dollar boost elbows and your stock turbo can safely push 35-45 psi boost. At 35-45psi, the HE351 flows more CFM/lbs per minute of air than the SuperB.
2. Spoolup is so quick with the HE351 that it is not an issue by most people's standards.
3. The He351 over S400 twin setup is a great towing combination that sacrifices a little spoolup for more top-end airflow. In fact, if you a person spent a few hours with a dremel or die grinder, the wastegate passage can be opened up large enough to make this twin turbo setup capable of 650-700HP.

Bigger, better, faster is all relative. If a person is never going to shoot for 600HP, no need to sacrifice spoolup with a large set of twins S480 over 115mm HX82 Billet.

If you want fast spoolup and 350-575 HP, the BD towing twins are perfect.

I'm a firm believer that slightly undersized turbos are much more fun for daily driving than a turbocharger that will perfectly support every drop of fuel your maximum tuning settings can deliver.

 

Good info BB24, thanks!

 

This is all true except the bold portion. As I'm sure most know, there is a trade off between drive pressure and hp. The higher the exhaust restriction, the harder the motor has to work to produce power. However If 5 more psi exhaust drive pressure results in 5 more lbs per minute of airflow then it's a good trade off. The reasoning is that lets say increasing exhaust drive pressure 5 psi steals 10 hp from the motor but on the other hand, lets say the 5lbs per minute of extra intake airflow creates 40 more HP. The net result is 30 extra hp. In this scenario, reducing drive pressure did not result in the motor running stronger.


Regardless of what has been misstated countless times in the past, the compressor of a turbo will flow more and more air the faster it is turned until it either fails/turns into shrapnel or goes into a surge condition. It is true that efficiency rapidly falls off and so lots of heat is added to the charged air but it still has more mass flow.

However, the power to turn the compressor wheel comes from the exhaust turbine wheel. As the compressor is spun faster and faster, it requires more and more shaft hp. As efficiency falls off sharply, the net gain goes down extremely fast. For example, it might take an extra 20 psi of drive pressure to make one addition pound per minute of airflow. 20 psi of exhaust drive pressure might steal 20 hp and only produce 8 HP from the additional intake air flow. That example would result in a loss of 12hp by pushing the turbo too hard.

In my opinion, most turbos will go into a top-end surge condition or completely fragment before reaching the point of additional airflow equates to less total hp.

 

I couldn't agree with you more Big Blue 24, I too find having slightly undersized turbos more fun for daily driving. From my experience the Edge was producing higher EGT's than I liked so I wanted to cool it with a new turbo. Everyone talks about how great twins are, and because I live in Canada, BD is one of the stronger products up here. I went with the Super B, knowing that the Tow twins would be in my near future.

 

Pat, what turbine housings are on each of the twin primary turbos?? We know they're a T4 flange but what about the A/R and exducer size??

And doesn't the Super B move more like 60lb/min not the 87 (or even 80) mentioned earlier?? If you look at the BW compressor maps in the 2007 Airwerks catalog the sample for S300's is based off of a 59mm compressor wheel, the choke line doesn't even extend to 66lb/min at 111K turbo speed. 60lb/min puts it right in the ball park of 870 cfm based on the garret conversion

 

The super B special moves 80 lbs/min. The regular super B does 60.

 

good catch... my bad.