Thinking About Monoblade

[Jam421]

I did not realize L&M was still in business ! My buddy's old L&M failed last year which he replaced for the CJ65mm. Catmonkeys info about the twin 71mm (1755cfm) makes me think about contacting L&M as the steadiness of the twin + cfm makes sense. Currently I'm running a port matched BPS elbow so matching that to a new TB is an easy option. Yikes.....I was thinking one or the other. I'm making my decision this coming week but now ...so much to think about ! But that's a good thing ->) !
99Vert.........Luvin your candy apple red vert ...I've got the same combo!
PM sent.

 

[biminiLX]

If you have the BPS elbow I have a BPS twin 73 TB sitting here. It was Sylvain's personal TB he took off his car and overnighted to help me make an NMRA race. PM if you are interested. It's black and has some airflow tricks.
-J

 

[Jam421]

BiminiLX........Got your PM. TTYL.

 

[Jam421]

Bimini ....didn't hear back from you but that's cool Bud. Is BPS still making that TB ? I could not find it on their website for a visual. I get the power increase for racing but how was that particular TB for driveable street tuning ?? I'm speaking to my tuner tomorrow . I would like to learn more about his experience with tuning the MB versus the twin. If I'm in the low 700's rwhp perhaps a larger twin ...you know ....upgrading my VMP 67mm to the VMP 72mm might suffice to give me a good cfm bump and have more room than my power level requires in this.....Eeerrrr Final Mod. Yeah Right !
99Vert......Interested in your IW 10%. Sent you a PM about it. Thnx Guys !

 

[biminiLX]

Sorry been busy til late and didn't want to call your home phone late, shoot me a text if you can. I took TB pics on my cell and also have an IW 15% if you don't have the track pack coolers it would work well.
Who is doing your tuning?
-J

 

[Jam421]

Hey guys.....maybe we can look at TB's another way ? I understand the FRPP mono outflows the CJ65 & VMP67. And....I love the fact just this swap can safely make more HP & a bit more boost with cfm rather than more heat on the blower. That "beats the pants off" just adding an additional 1-2lbs boost.

Has anyone pulled a CJ65 or VMP67 swapped it for a VMP72 or other larger Twin Blade and measured the performance difference ??

 

[Ben99GT]

The Ford Racing SCJ makes more power than the VMP 72 even on ~700 rw combos.

The SCJ made an extra 0.7 psi, 8rwhp and 11 lb-ft vs. a VMP 72 on a 08 GT500 with ported Trinity, 10% lower, 2.4 upper and JLT 127.

Same ECT/IAT2, pulls made 15 minutes apart with no other changes. True back to back pulls.

 

[Ben99GT]

Apparently Ford Performance rates the CJ 65mm at 1,517 CFM and the SCJ mono at 1,797 CFM. Difference is 280 CFM, so that info wasn't far off.

I also came across info that L&M rates its 66mm twin at 2,000 CFM and the 72 mm twin at 2,500 CFM. Clearly they're using a different pressure drop to measure CFM than Ford Performance and everyone else in the industry.

Whipple has a 68mm twin and 71mm twin it rates at 1,630 CFM and 1,755 CFM, respectively.

Kenne Bell rates its 75mm twin at 1,880 CFM. They also indicate the stock TB flows 1,128 CFM.

To put it all in perspective, a TVS with a 2.4" upper, a 15% lower and an engine turning 6,500 rpm (blower rpm of 21,992) would generate 1,786 CFM, which assumes 100% efficiency and that the case and/or elbow can flow that much air.

For the pump gas guys, a TVS with a 2.4" upper, stock lower on an engine turning 6,500 rpm would generate 1,562 CFM. That's not to say a larger twin TB wouldn't make more horsepower than the CJ 65mm, but there comes a point of diminishing returns.

VMP Gen 2 TVS, 2.4 upper, stock lower, 123 JLT. SCJ mono vs. VMP 67. SCJ is red.

 

[Ben99GT]

Last graph was a 2011 GT500, SCJ increased boost by 1.5 psi over VMP 67

 

[biminiLX]

It's very simple, ANY reduction in restriction before an PD blower will make more power. Like a mass air meter/CAI tube, you gain power up to the point it eliminates the restriction and after that, it won't make or lose power but it may sacrifice driveability.
So that's really the issue, trying to make as much power as possible w/o sacrifice in street manners.
I haven't had enough street time with the big Whipple 170mm oval on my current combo, but the BPS twin 73 was great driving and made power. Many say with the right tuner you won't lose any manners with the ovals, but then really how important is 10hp on a 700+rwhp deal if you never track it?
-J

 

[biminiLX]

Missed your question but no I don't believe BPS is currently advertising the TB but may make them if requested. To me it looks almost identical to the L&M/VMP 72, so maybe that's a reason.
Some had issues with tuning it, so BPS only recommended a few tuners. Lund tuned mine with a big 155 JLT at the track and I had no street manner issues with exception of some surging with cruise control on. May have been the TB, CAI or combination or something else. I never addressed it as it wasn't a big deal to me.
-J

 

[mebetter]

Very interesting thread; I think I may do the swap from the CJ tb to the SCJ TB.

 

[Catmonkey]

Many say with the right tuner you won't lose any manners with the ovals, but then really how important is 10hp on a 700+rwhp deal if you never track it?

If that. Difference of 8 rwhp is at the peaks. Looking at average numbers, you're probably half of that. One back to back pull doesn't make a believer out of me. Run what makes you happy. I don't see enough difference to chose one over the other.

 

[Ben99GT]

If that. Difference of 8 rwhp is at the peaks. Looking at average numbers, you're probably half of that. One back to back pull doesn't make a believer out of me. Run what makes you happy. I don't see enough difference to chose one over the other.

The difference is greater than 8 at the start of the pull and after peak.

 

[Ben99GT]

Also, the boost increase shows the VMP 72 was a flow restriction at 715 rw, that gap is only going to grow as airflow demands increase.

 

[Catmonkey]

Your results may have been tuned related as well. Did you do any port work at the inlet near the throttle bores or did you leave airflow disturbed at the top and bottom of the throttle bores at the inlet lip? Did you do any data logs to see what was going on with your fuel trims? You assume restriction accounts for decrease in boost, yet there would be no restriction at lower rpms. In other words, you're making one assumptions based on a single pull, no data logging, no experimentation with the tune to make possible improvements, no improvements to entry airflow. You're not even making an attempt to be objective. IMHO, your dyno numbers aren't worth the paper they're printed on.

And if you don't mind, quit stalking me. I guess I need to put you on ignore here too, now that I've figured out who you are.

 

[Ben99GT]

There were no timing or A/F ratio changes.
The dyno runs were absolutely logged, and fuel trims were fine.
There is no entrance mismatch whatsoever with the Twin 67, despite the 24 RWHP and 1.5 psi boost gain with the SCJ.
The Twin 72 received no port matching, as this was a ported 5.8 blower with an already ported inlet elbow. The gains are legit.

And please, tell me who you think I am. "Stalking" you? How can I stalk a person I don't know and have never heard of?

 

[Ben99GT]

NT

 

[CD07GT500]

Catmonkey can't face the truth. CJ mono > twin 72 period.

 

[Beercules]

The simplified reason a mono TB should flow better than a dual TB (given equal open area) is because there's less surface area for the for the air to 'stick' to. The diagram below shows the effects of surface tension (friction) in a pipe (intake tract).

However, the shape of the TB will be. A big modifier to the above statement as shown below.

As your inlet/ outlet shape changes, your headless (frictional forces) will change.

There's a lot to calculate there. I prefer looking at tested flow results to open area.