Originally Posted by
Lidio
Here it is…
This is the one that a lot of people are waiting to see and some probably don’t.
As slanted as this may appear to be to some because of the nature of this comparison. I’m posting it any way because I want to show the difference in low-end-torque between a roots blower and centrifugal type on a 4.6L, 4-Valve MM set up. This is the real deal between roots type blowers and Centrifugals. The main reason for this is to exemplify the difference in low end torque and off idle or as close to off idle TQ each one makes. In no way is the tune responsible for the obvious difference between the two.
First I want to say that I’ve tuned a lot of Vortech equipped cars in the last 12+ years and have really excelled in it the last couple of years because of our dyno and software we now use. Tuning a centrifugal car for us is no big deal, we’ve done hundreds with proper and expected results. The difference in low end shown here is not the tune in any way. It’s the boost, or lack there of, down low. I know I’m repeating my self here.
The tune on the MM with the Vortech shown here was done totally by me because the owner of the car wasn’t happy with the facility that installed and tuned the combination initially here in MI. Sadly as can be seen in the dyno graphs, the blower belt squealed and slipped causing a boost drop at the high end of the pull. This made the Vortech equipped car obviously not make the over all high RPM power that it was capable of. But this post and these graphs are to show the difference in low end torque between the two.
Just a side note… The blower belt on a Trilogy set up is its own stand alone 8-rib belt just for the blower. The Vortech set-up’s use one 6-rib to support all the accessories and the blower too.
Also the Cyntrifugal equipped car had long tube headers and only the stock front two cats removed, not all four. I’m not sure why this was done. I feel leaving the rest of the system stock especially the mufflers, negates the use of the headers. I also feel that the centrifugal equipped car would have made a pretty impressive peak number had the boost not fell off. As you can see in the graph, the boost was continuing to rise pretty good on the Vortech car and probably would have hit 9.5 to 10psi and a least 390-400+ RWHP.
Not to many people I know… in-fact no one I know at this time (except for JW @ SCT) is doing what I do with the trans shifts and converter here (when dynoing) . Where I set it up to “not” down shift out of third gear once its over 25mph and lock the converter the whole time. As I’ve said before, this shows a very real Torque and HP pull just like a stick shift car would on a chassis dyno. This showing of the amount of low end these have is what’s felt and used the most on heavy street cars from street light to street light and day to day!
Just for some added info and data, I also posted a dyno graph of a Stick-shift ’03 Mach-1 we did a Vortech on recently… which ran very good with long tubes and a full 2.5” exhaust with two hi-flo cats too.
The ’03-’04 Mach-1’s have the same motor as the MM’s except the stick-shift Mach-1’s got a steel crank. The MM’s and auto trans Mach’s got a cast crank.
The Mach made the power and torque over all like it should from 2000 RPM’s all the way up. The Mach makes more then the MM with a Vortech over all because of less power train losses and it’s a stick shift.
This is all good and honest data for those interested in a blower for their cars. It’s a pretty fair example of the low end grunt differences.
As can be seen in the Trilogy’s low end torque… this is the reason a Trilogy MM will run very good with nothing done to it at all other then the Trilogy blower kit. They perform very well with out a loose, after market torque-converter and do very well with the stock 3.55s in axle too. Although they wake up more with additional boost and other upgrades as well.
Thanks
I was just reviewing the boost curve that Lidio posted a few weeks ago and I have a question concerning the Centrifugal Superchargers......
The Centrifugal S/C boost curve rises with RPM and peaks at redline.
i.e. A 9 psi Centrifugal S/C does not make 9 psi boost until the very top of the rpm range.
Why can't you install a 14 psi Centrifugal S/C pulley and a bypass valve set at 9 psi?? That way you will get 9 psi boost much sooner in the rpm range and hold 9 psi until redline??
That's what all Turbocharger systems do....build boost to a preset limit, then the bypass/blow-off valve holds that level of boost until redline.
2020 Ford Ranger STX DFI Turbo 2.3L 10 speed Auto
2017 Ford Fusion Sport DFI Twin Turbo 2.7L V6 6 speed Auto (14.000 ET bone stock in 82 degree heat)
1985 Mustang GT 5.0 Hatchback 4bbl 5 speed manual (525 HP 363 Dart block/AFR heads with Magnum 6 speed in the works)
1984 Mustang GT 2.3 Turbo Convertible FI. 5 speed manual
1966 427 Cobra (ERA) 468 all Aluminum FE 2x4bbl 5 speed manual
SOLD : 2003 Mercury Marauder FI. 4 speed Auto
w/Crower Cams & Springs, +1mm SS valves, mild port job on the cylinder heads.
Extrude honed intake w/PHP spacer.
Kooks Headers w/2.5" High Flow Cats & X-Pipe, Magnaflow mufflers, OEM tailpipes w/Megs Tips
B&M Trans cooler w/fan, Level 10 Shift Kit, Art Carr Hughes Deep Sump Trans Pan,
SVO Rearend Girdle, Redline Gear lube; OEM 3.55s
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