[toohighpsi]

Originally Posted by KingLT1

You ran the 2650 +3 psi over the 2300, why would you only expect 20hp?

The drive ratio was chosen to deliver similar boost from both units. See plot below. The match ended up at about 4500 RPM, but as can be seen in the plot the blowers have different boost characteristics which result in lower boost at lower RPM and higher boost at higher RPM. Peak power also occurred at a higher RPM additionally aiding in the increased power.

I didn't get power to peak at 7K, but didn't want to spin my otherwise stock rotating group much past there.

I have created a video wrapping up the results on my LT4, but I guess it didn't get dropped last week. I left the shop on Thursday to hit Camaro Fest, I'll make sure it's posted next week when I'm back.

[radz28]

Originally Posted by toohighpsi

The drive ratio was chosen to deliver similar boost from both units. See plot below. The match ended up at about 4500 RPM, but as can be seen in the plot the blowers have different boost characteristics which result in lower boost at lower RPM and higher boost at higher RPM. Peak power also occurred at a higher RPM additionally aiding in the increased power.

I didn't get power to peak at 7K, but didn't want to spin my otherwise stock rotating group much past there.

I have created a video wrapping up the results on my LT4, but I guess it didn't get dropped last week. I left the shop on Thursday to hit Camaro Fest, I'll make sure it's posted next week when I'm back.

Attachment 995733

Looking forward to that video! 🙂

[Drsagacity]

Originally Posted by oldman

Sorry but a uncorrected is really the "correct" way to report FI... The really skewed comes about putting in a CF designed for a NA application. Not to mention 1 percent should be about the max added...

[ShizzySupra]

Ya’ll can measure intercoolers in the locker room until your satisfied...only one 2650 was represented at CamaroFest and performed STRONG in terrible conditions.

Congrats Magnuson crew! Cant wait to see as the cars grow more!

[laynlo15]

Thanks Shizzy. We did our best for the conditions and proved to be a pretty good combo. We were both running pretty low boost for what we normally run. Waiting on some smaller pulleys to be produced to make some more power. Track was pretty hot and slippery so we had to be careful about power on the launch. I was spinning the tires on every pass. I was spinning the tires way down track on one pass and the car was swaying a bunch, Billy was having the same issue.

[toohighpsi]

LT4 Magnum DI TVS2650 wrap-up video.

[radz28]

I have to see how to run METH in CA, hahaha...

[oldman]

Originally Posted by Drsagacity

"The correction factors that we use in our dynamometer software are not
valid with forced induction applications. The most popular correction
factor, SAE CFJ1349 JUN90 and J1995 JUN95, does not account for the
conditions present in boosted applications. Atmospheric pressure is the
major component of this calculation, and anything that varies from the
standard (29.235 inHg) can easily be corrected for NA applications. When
you are forcing an "artificial atmosphere" into your motor, these
standards go out the window.

Technically any boosted car should be viewed as uncorrected if you want
to compare apples to apples. If we had a correction factor that just
took into account temperature and humidity, that may make things easier
to compare in boosted applications. If you are forcing 1 atmosphere
(14.7 psi) in your motor at 6,000 feet, or 1 atmosphere at 100 feet,
that's really the same difference.................IF you are measuring
manifold ABSOLUTE pressure, it's absolute, don't rely on a standard
boost gauge to give you an absolute value.

Regards,
----------------
Dan Hourigan" Vice President DynoJet

Many other white papers and posting, but go ahead and apply the ricer STD unicorn HP and yes a unicorn is a horse, to FI....

You might want to read here
Larry'sCF = (1.19396) x (1.05437) = 1.25887 <---- this would be the correction factor appropriate for a NA engine. For a turbo charged or supercharged engine you would have to also include a correction for the boost pressure, because the difference between sea level absolute manifold pressure and high altitude manifold pressure when expressed as a ratio would change the higher your boost pressure became.


For example = 20 psi boost at 29.24 in-hg, vs 20 psi boost at 24.41 in-hg air pressure

would be 40.7 in-hg boost, plus 29.24 in-hg atmospheric pressure = total manifold absolute pressure of 69.947 in-hg.

20 psi boost at 24.41 in hg air pressure = 65.11 in-hg abs

the ratio is 69.95/65.11 = 1.074 correcton at 20 psig manifold pressure

if the boost is only 10 psi, the ratio becomes 49.59/44.76 = 1.108 correcton at 10 psig manifold pressure

So the higher the manifold boost, the lower the effect of altitude. Compare the two boosted values above to the 1.194 correction factor due to air pressure in the NA case.

This all assumes there are no effeciency changes in the turbocharger or suprecharger due to altitude which we all know is not the case, but much better than the standard SAE formula.

So my final modified correcton formula for the example should be:

Larry'sCF = ( [(boost)+29.23]/[(boost)+24.49]) x ((101.41 +460)/505) ^ 0.5

metric
Larry'sCF = ( [(boost)+990]/[(boost)+829]) x ((38.56 +273)/298) ^ 0.5

boost = manifold gauge pressure in millibars.
millibar = 0.1 kpa
in-hg= 3.386389 kilopascal (kPa)
1 atmosphere= 101.325 kilopascal (kPa)
1 psi= 6.894757 kilopascal (kPa) = 68.94757 mb

Boost expressed as in-hg = 2.036 x psi
Boost expressed in mb = 68.9116 x psi


***********************

boost = manifold gauge pressure in millibars.
millibar = 0.1 kpa
in-hg= 3.386389 kilopascal (kPa)
1 atmosphere= 101.325 kilopascal (kPa)
1 psi= 6.894757 kilopascal (kPa) = 68.94757 mb

Boost expressed as in-hg = 2.036 x psi
Boost expressed in mb = 68.9116 x psi


=================

In general form the modified factor would be:

Metric
Larry'sCF = ( [(boost)+990]/[(boost)+Pd]) x ((Tc +273)/298) ^ 0.5

english
Larry'sCF = ( [(boost)+29.23]/[(boost)+Pd]) x ((Tc +460)/505) ^ 0.5

Boost= manifold gauge pressure
Pd = local dry absolute air pressure
Tc = local ambient air temp
https://forums.nasioc.com/forums/sho...d.php?t=873912

[IneedAZ]

Originally Posted by toohighpsi

LT4 Magnum DI TVS2650 wrap-up video.

How are the 2300 and 2650 tuned for the testing? Another words, it doesn't seem that it was tuned to be more balanced with the HP & TQ numbers. There is a huge difference in your HP and TQ numbers on the 2650. I would expect the HP to drop some and TQ go up. Maybe a 50 spread, or is this common with the 2650?

[ShizzySupra]

Has to do with the efficiency of the blower. It simply breathes better which is why the 2650 simply runs away in power as the RPM’s rise.

Originally Posted by IneedAZ

How are the 2300 and 2650 tuned for the testing? Another words, it doesn't seem that it was tuned to be more balanced with the HP & TQ numbers. There is a huge difference in your HP and TQ numbers on the 2650. I would expect the HP to drop some and TQ go up. Maybe a 50 spread, or is this common with the 2650?

[laynlo15]

Run the Meth in the elbow of your intake tube. Put a plug in the elbow when its time for your inspection

[ramairroughneck]

Originally Posted by ShizzySupra

Ya’ll can measure intercoolers in the locker room until your satisfied...only one 2650 was represented at CamaroFest and performed STRONG in terrible conditions.

Yep but Edelbrock stands on top amongst PD blowers in 1/4 mile times on the 6th Gen Camaro, 18 Coyote Mustang, and CTS-V3. You could say it’s representing many platforms.

[ShizzySupra]

Originally Posted by ramairroughneck

Yep but Edelbrock stands on top amongst PD blowers in 1/4 mile times on the 6th Gen Camaro, 18 Coyote Mustang, and CTS-V3. You could say it’s representing many platforms.

The Edelbrock is nowhere near top of the heap for the LTx series GM’s. A baby 2.3 Maggie is faster and quicker ( Mikes car) also a Maggie 2650 is faster and quicker as well (Magnuson shop car).

[wnta1ss]

Originally Posted by ShizzySupra

The Edelbrock is nowhere near top of the heap for the LTx series GM’s. A baby 2.3 Maggie is faster and quicker ( Mikes car) also a Maggie 2650 is faster and quicker as well (Magnuson shop car).

Actually, the Edelbrock 2650 on a 6th-gen has already run in the 8s. Also the 1/8 mile for the Edelbrock was a 5.67, which is better than the 5.85 that the Magnuson guy reported for his shop car. Looks to me like ramairroughneck is right, and you are wrong.