5.0 Mustang & Super FordsHow To Engine
Novi 2500 Supercharger Dyno Test - Nouveau Novi
Project T-top Coupe returns with Paxton’s all-new race blower, and a lot more power
Readers who have been with us since 2006 should be plenty familiar with the '86 T-top project Mustang. For our newcomers, the rare coupe is a thrice-resurrected, Paxton-supercharged LX that your author has been working with since 2006. We've chronicled every highlight (every step of its initial Fox Rod resto; running the length of a dragstrip in 9 seconds; winning numerous car-show awards) and lowlight (two catastrophic engine meltdowns) the project has experienced in the last six years.
For the full skinny on T-top Coupe, you'll need to scour your 5.0 Mustang & Super Fords library (the first story, "Raisin' the Roof," appeared in our May '06 issue), or scroll through the Tech Section of our website to find past articles covering the entire saga.
For this effort, recording what we hope will be 1,000-or-more horsepower at T-top Coupe's feet has been our ambition from the moment we realized Engine Two—which pumped out 866 horses and 727 lb-ft of torque—had gone by the wayside during a qualifying pass at the PSCA's Street Car Super Nationals V. To reach that next plateau, major changes to the engine and the Mustang itself were made.
The upgrades, which are detailed in the most recent reports on the project car ("Grand Scheme," Mar. '11; "To the Top," May '11; "Cold Case," Oct. '11), highlight A.R.E. Performance & Machine's design and assembly of a brand-new 353ci powerplant and its installation at Extreme Automotive, and the slick Earl's-based plumbing arrangement (ice tank, water feed/return lines) that we set up for a water-to-air intercooler.
While a lot of critical detail on the latest resurrection has been covered in those past reports, the time has come for us to turn our focus on the higher-profile pieces that comprise T-top Coupe's big-steam package. Power hardware still includes the project's original Paxton Novi 2000 supercharger, which we're using to establish a performance baseline for the new engine. However, the upgrade that really has us over-the-moon excited is Paxton's all-new Novi 2500 head unit, which we're bolting on Couptie's 353 immediately after power and torque peaks with the OG Novi are established.
Yes, that's right—while we've alluded to and hinted about the new Paxton in past reports here and through our blogs and social-media pages, we're finally putting the much-hyped blower to the test. (If you follow or believe Internet buzz, insiders at Paxton are saying the newest Novi has what it takes to possibly end the Vortech YSi's dominance in NMRA's EFI Renegade class.) It's a good-old, back-to-back comparison in the dyno cell at Extreme Automotive in Canoga Park, California.
The following photos and captions include highlights of some of the final modifications that were made before our monumental test, as well as images of and all-important data from the tuning, dyno-, and dragstrip testing that was performed.
Horse Sense: The title for this segment of our six-year, Life-and-Times-of-Project-T-top-Coupe series definitely sums up, in a nutshell, the latest status of the rare '86 LX. We say this because after just about two years of downtime, the Fox coupe with T-tops once again is in a condition that's worth talking about—running, and we have to modestly admit, it's running pretty damn well.
Paxton Novi 2500
After almost 20 years of being considered one of the best all-around superchargers for push-rod-based Mustangs (since hitting the scene in 1994, the Novi 2000 has been a great starter/8-psi blower on stock 5.0s, or a 20-plus-psi unit on radical stroker engines), it's safe to say that updating Paxton's standard was long overdue.
The changes, primarily in the blower's impeller and volute, appear to be for the good, as the new Novi 2500's estimated peak efficiency of 76 percent, is a whopping 5 percent greater than the 2000, that's just a tick below that of Vortech's NMRA EFI Renegade-proven YSi-Trim supercharger (78 percent).
Paxton and Vortech have waged a civil war for many years on the street and strip, with the Novi 2K proving to be a true beast for street-based Mustangs, and the YSi having an edge on Ponies that cover the quarter-mile—especially when they're turned with cog pulleys. Based on the data we studied before conducting this test, it appears the playing field is level now. The dyno will show us the performance differences and the areas where the new blower hopefully shines over its older sibling.
Unfortunately, we're not pitting the Novi 2500 directly against the YSi in this test. Comparing our results against existing data for the Vortech (for engine packages similar to ours) should provide enthusiasts with a good idea of how the two blowers match up.
This impeller and redesigned volute are the keys to the Novi 2500’s higher rpm and overall efficiency when compared to its predecessor. The OG Novi features a larger-diameter (but shorter 3.53-inch height) impeller. As you’ll see in comparative data elsewhere in this report, the design generates excellent low-end boost. The 2500’s impeller is smaller in diameter and the volute has been lengthened to accommodate its taller (3.75-inch) stance. The changes move the new unit’s max-rpm window well beyond the 75,000 of the Novi 2000. Note that Paxton does not list the Novi 2000’s or 2500’s maximum speeds as being that high. The coupe’s previous 10-rib pulley combination turned the 2000 to an estimated 75,000 rpm, which actually is alarmingly high for that unit. At that speed, the outer edges of the large impeller usually start to wobble, which leads to the impeller touching down on the volute and wreaking havoc from there. This new design alleviates high-speed wobbling, which contributes greatly to the 2500's efficiency (approximately 76 percent) on the high side.
Engines in our T-top project car have always been commanded by FAST's XFI fuel-injection system. We've had great success using XFI for engine management, and consider it one of the best stand-alone EFI units for aggressive street/'strip Mustangs.
During the coupe's rebuilding period, we received word that XFI was also being revamped. And, of course, we immediately had interest in trying it with our new engine and intercooled Paxton Novi superchargers (2000 and 2500).
The new XFI, Version 2.0, retains many of the features of the first-gen system. However, engineers at FAST and tuning consultant Brian Macy of Horsepower Connection have brainstormed and developed quite a few new functions for the new ECU. Features such as Intelligent Traction Control and Self Learning are among the new additions to XFI, which give both amateur and experienced tuners the ability to dial in Mustangs for just about any driving condition.
We sent the 'Stang's original XFI processor back to FAST, and a few weeks later received the upgraded 2.0 ECU (FAST performs the hardware upgrade for $99.95). We were fortunate enough to catch up with Brian Macy for help with nailing down calibrations for our Mustang. (Brian travels all over the country giving classroom lectures, tuning in dyno sessions, and consulting with FAST on XFI features.)
Our tuning with XFI 2.0 took place over the course of two days in your tech editor's driveway, where preliminary parameters were established. It continued in the dyno cell at Extreme Automotive, where we set out on our mission to make big steam.
On The Dyno
Hands down, our two-day dyno extravaganza at Extreme Automotive was one of the most-exciting power sessions we have ever had with Project T-top Coupe.
We evaluated the coupe on Extreme's Dynapak Evolution 4000 chassis dyno using two intercooled superchargers (Paxton's Novi 2000 and all-new Novi 2500) in a back-to-back comparison test to see how the two Novis will affect the same engine. Of course, we also were on a mission to make 1,000 hp at the project Pony's rear wheels.
The data presented here, in graph and numerical chart form, detail all of the results from our extensive testing. While in the chart we begin with the inclusion of results from previous tests we made with a non-intercooled Novi 2000 (2), the difference between the two intercooled Novis (2000 II and 2500) is the data that is published.
While our rear-wheel-goal was not reached, it's estimated the coupe's new Novi 2500 combination is producing approximately 1,106 hp at the flywheel. We're sure you want to see that type of number at the feet--as do we--so our plan is to keep plugging away with this project until we finally make it to the four-digit promised land, a land we never thought to achieve when this project started back in 2006.
On the Dragstrip
"If it weren't for bad luck, I wouldn't have any luck at all." Believe it or not, your tech editor was starting to feel that way about racing at The Strip at Las Vegas Motor Speedway.
Luck had been nothing but bad in two previous attempts to compete at the PSCA's Street Car Super Nationals—broken T-top Coupe engine in 2009/broken '02 GT rearend in 2010—and apprehension about the third try was at an all-time high. Despite this, and with Big Steve along for the ride, we journeyed back to Vegas for SCSN7 in November of 2011, hoping the mechanical demons of the past would not play any role in this attempt.
We would love to tell you that SCSN7 was a picture-perfect experience for the 5.0&SF team and the other participants (including NMRA Hot Street racers such as Robbie Blankenship, Don Bowles, Ben Mens, and Mike DeMayo), who traveled from far and wide for the race. Unfortunately, that wasn't the case. Despite great weather throughout the weekend, carnage (mainly engine failures/oil leakage) wreaked havoc on the event's schedule.
Adjustments in the schedule and minor gremlins with our Mustang (a grounded kill switch and broken blower belt) forced us to abort our two attempts at qualifying, leaving us with limited data going into the first round of eliminations in the Ford Racing Mustang Maddness class (an Open Comp-format category for Ford-powered Mustangs). Since we didn't have an e.t. recorded from a full qualifying pass, PSCA officials allowed us to select an index to use throughout eliminations. After deliberating over a full-out pass or actually trying to race and win one or more rounds, we chose the latter option and elected to run against an 11.00 index. In most instances, running an 11.01 on an 11.00 index is a package that's difficult to beat. However, with a 0.541 reaction time (to Kevin St. Clair's 0.067 light), T-top coupe hit the trailer after the first round.
How did the project car do on the track? Despite the lack of making a full run, excellent, mainly because we brought it back from Las Vegas without experiencing any catastrophic breakage.
A review of the car's XFI 2.0 datalog and the incremental data from the 11.01 run show that the coupe was on its way to a mid-10-second e.t. in its only round of competition despite horrendous inconsistencies in throttle and rpm (driver off-and-on the gas). The e.t. and mph at the eighth-mile were 6.808/100.97. When we look at the 6.80 time plot on the datalog, throttle position is barely over 42 percent, and never reaches a full 100 percent until 8.80--2 full seconds later--and rpm is barely 5,000-5,300. Add to that the revelation that--despite "thinking" the pedal was slammed wide open all the way through the run--the throttle blade actually was slammed shut from 1,000 feet through the end of the quarter-mile (the datalogger doesn't lie). The numbers show that Project T-top Coupe, with its 3,610 pounds (w/driver), 908 rear-wheel horsepower, and 700 lb-ft of torque, is by all means an animal that should run low 9s, or maybe even high-8 seconds.
We're definitely excited about getting Couptie back to the track and making a full pass in 2012. However, until that time comes, the 'Stang once again will see fairly regular cruise duty on the streets of SoCal's San Fernando Valley. After all, it is a street car.