Latest Development: 4.25L GT4 Performance Engine Upgrade

The street engine was designed with TQ as a priority and plenty of HP, we wanted a motor that pulled strong from 2500 to 6000 RPM.  Our 4.25L engine in street trim produced 376.2 rwtq at 5600 rpm and 445.5 Peak HP at 6300 rpm.

The “Street/Race” version of the 4.25L engine was developed with maximum peak HP in mind. Utilizing the factory GT3RS intake manifold we mated it to our 4.25L engine to produce 488.5 rwhp at 7900 rpm with 360 rwtq at 6200 rpm.

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DeMan Motorsport

Exclusive Porsche Service, Performance, and Race Car Builder

DeMan Motorsport

Porsche Specialists

A one-stop shop for all your Porsche needs, DeMan Motorsport offers everything from routine maintenance and service on your daily streetcar to fully built race cars and support.  Please stop in and see our  25,000 square foot facility. – it’s a dream for any Porsche enthusiast!

4.25L GT4 & 4.0L CAYMAN ENGINES | GT4 ROLL Bars & Upgrades | Competition/Track Preparation | Track Support | Used Vehicles Sales | Large Parts Inventory | Complete Collision Body Shop | Restoration | In-house Dyno Tuning

OUR SERVICES

WHY CHOOSE DeMan Motorsport?

With over 30 years of experience, the DeMan team specializes in all this Porsche from engineering championship winning race cars to bumper repair on your street car.  DeMan Motorsport caters to street and race cars alike and is located just minutes from the Tappan Zee Bridge.

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VEHICLES FOR SALE

We normally have a mix of street cars and race cars available for sale.  Our inventory is constantly changing and we are always looking for vehicles for clients so please contact us if you are in the Porsche market to buy or sell.  

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DeMan Motorsport parts

We sell a wide variety of Porsche parts from racing only parts to street car items.  We have a large inventory of factory parts removed from street cars that were turned into race cars including, engines, transmissions, full interiors, wheels, exhausts and much more.  Featured racing parts include brakes, aero kits, exhausts, and wheels. 

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Horsepower Thursday!
The GT4.5 at MMC.
Drivers reviews of this car off the charts! Here is Andrew Wong after his first drive. 
The 4.5L is SAVAGE!
I got a little time in the development car yesterday and it is one angry GT4! The car is the full package with everything - 4.5L, exhaust, lwfw, short gears, and who knows what else but it is far from stock. The mid-range hit going WOT totally caught me off guard, I cursed, then I held on, then I laughed my ass off after I pulled the next gear and could breathe again. I think if you crossed the old C63 NA AMG v8 with the GT3 engine you'd get something like this - aggressive, motorsporty, and silly fun. It's not just the power, it's also the power delivery. The combination of a lwfw, shorter gears, and the torque everywhere 4.5L makes for insane throttle response and a sharp smack of G forces when you get into the gas. Where the 3.8L makes power with an elastic surging kind of feel, this is shockingly immediate and abrupt, you get into the throttle and you don't get pushed into the seat, you get smacked in the face. Sure the 4.5L car with that set-up and tune the new fastest most powerful GT4 but what really struck me is that car is just oozing character now. The engine is so dominant in the 4.5L that it changes the whole driving experience and turns the GT4 formula on it's head really. Lots of torque and short gearing has given the GT4 a whole new ridiculous and hilariously hoonable side at street legal speeds like BMW M cars or modern muscle cars. @fastwong #gt4.5 #caymangt4 #porsche #gt4rs #porschecayman #gt3rs991 #gt4clubsport @robbholland3
Horsepower Thursday! The GT4.5 at MMC. Drivers reviews of this car off the charts! Here is Andrew Wong after his first drive. The 4.5L is SAVAGE! I got a little time in the development car yesterday and it is one angry GT4! The car is the full package with everything - 4.5L, exhaust, lwfw, short gears, and who knows what else but it is far from stock. The mid-range hit going WOT totally caught me off guard, I cursed, then I held on, then I laughed my ass off after I pulled the next gear and could breathe again. I think if you crossed the old C63 NA AMG v8 with the GT3 engine you'd get something like this - aggressive, motorsporty, and silly fun. It's not just the power, it's also the power delivery. The combination of a lwfw, shorter gears, and the torque everywhere 4.5L makes for insane throttle response and a sharp smack of G forces when you get into the gas. Where the 3.8L makes power with an elastic surging kind of feel, this is shockingly immediate and abrupt, you get into the throttle and you don't get pushed into the seat, you get smacked in the face. Sure the 4.5L car with that set-up and tune the new fastest most powerful GT4 but what really struck me is that car is just oozing character now. The engine is so dominant in the 4.5L that it changes the whole driving experience and turns the GT4 formula on it's head really. Lots of torque and short gearing has given the GT4 a whole new ridiculous and hilariously hoonable side at street legal speeds like BMW M cars or modern muscle cars. @fastwong #gt4.5 #caymangt4 #porsche #gt4rs #porschecayman #gt3rs991 #gt4clubsport @robbholland3

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