Dale Amy
March 1, 2009
How much power can be unleashed by swapping the new R2300 Roushcharger into the space previously occupied by a Roush 427R's Eaton M90-based blower? Lots, but read on. Stage 3, 427R, and 428R Roush owners looking for way more boost and blower efficiency should find this a satisfying and relatively simple upgrade. The upgrade kit retails at $4,999.

Horse Sense:
The inherently quieter and smoother rotor/lobe design of Eaton's TVS blower actually makes this a less complex package than earlier versions, as it eliminates the need for additional noise reduction treatments and hardware.

What follows is a look at the upgrade kit's hardware and the basic process of swapping it for the original M90 Roushcharger nestled between the 427R's cylinder heads

The new short-block will certainly allow turning up the wick of the efficient TVS blower through a more aggressive tune should the owner so desire

Roush Performance has recently made available its latest Roushcharger, a component combo that plops Eaton's thoroughly modern and efficient positive-displacement R2300 TVS supercharger atop a Roush-designed, aluminum manifold/intercooler assembly, logically called the R2300 Roushcharger.

The R2300 is currently the largest of Eaton's Twin Vortices Series of improved Roots-type superchargers. You may recall that Roush used this setup on last year's P-51A-and this year's P-51B-to produce 510, 50-state-legal flywheel horsepower. In comparison, other supercharged S197 Roush vehicles, like the Stage 3, 427R, and 428R, are force-fed by an older-but-still-potent-technology, Eaton M90-based Roots blower.

The heart of the latest Roushcharger is Eaton's 2,300cc, Twin Vortices Series blower with four lobes per rotor, twisted 160 degrees from end to end. In comparison, older Eaton designs had three lobes, twisted 60 degrees over their length. This new rotor pack combines with revised inlet and outlet ports to make for a blower that is more efficient and quieter than earlier Roots designs. The supercharger itself is by Eaton, but as you can see, all of the kit's supporting aluminum hardware have the Roush name cast right in.

The new R2300 Roushcharger is offered in three kit formats: complete with all of the intercooler/heat exchanger plumbing and hardware for any '05-'09 GT or unblown Roush; as an upgrade for owners of the aforementioned M90-Roushcharger-blown vehicles; and lastly, together with a stout, Roush-built short-block assembly that is internally the same as those used on the company's P-51A and B Mustangs.

The day we arrived with cameras and lights in tow at Building 50-one of the multitude of Roush buildings sprinkled in and around Livonia, Michigan-an Illinois owner had brought his '07 427R in for the TVS blower upgrade and short-block swap. By some cosmic coincidence, this turned out to be the same Redfire-hued car (No. 07-020) we had driven, photographed, and smoked the tires in our initial review of the 427R (March '07, p. 80)

What follows is a look at the upgrade kit's hardware and the basic process of swapping it for the original M90 Roushcharger nestled between the 427R's cylinder heads. Naturally we have some before and after dyno numbers, but we need to point out that the "before" numbers are a little higher than a stock 427R would normally produce, as its owner had previously swapped on a smaller pulley. The "after" numbers were generated with the new short-block in place, so given its slightly reduced static compression, these numbers are possibly a bit lower than would be the case if bolting a R2300 Roushcharger onto a stock GT. That said, the stronger guts of the new short-block will certainly allow turning up the wick of the efficient TVS blower through a more aggressive tune should the owner so desire. Scheduling conflicts kept us from hanging around and documenting the short-block swap, but we do have a sidebar on this new forged-internal release.

On The Dyno
As previously noted, our tester's baseline power numbers are likely somewhat improved over a stock 427R (or Stage 3, or 428R) by the increased boost of the owner-installed, smaller blower pulley on its M90 Roushcharger. Even so, by 3,100 rpm, the new R2300 Roushcharger had already improved torque by a butt-kickin' 149 lb-ft. You'd have to be dead not to notice that increased low-rev thrust. The combo also produces peak torque of 523 lb-ft at a low 3,900 revs and exceeds the 500 lb-ft plateau from 3,200 rpm all the way up to 5,200. On the rear-wheel horsepower side, peak improvement is 145, though point-to-point improvements of as much as 155 rwhp are evident. Overall, these increases clearly demonstrate the worth of the R2300 Roushcharger upgrade, especially considering our starting point was already supercharged and intercooled, and that we were going from Roots blower to Roots blower.