HP Differences

surfbeast · 03-07-2002, 08:50 AM

Anyone know what the difference is between the 99 and up GT with 260hp and the 98 GT with only 225 hp. What did they do to get the extra 35 hp?

Thanks!

SLOW 97 · 03-07-2002, 10:20 AM

The '99- up GT's have what are called PI (Power Improved, Product Improved, whatever you think it stands for) heads. These heads flow considerably better than the non-PI heads on my car. The intake manifold is also slightly different on the '99-up's. Another difference is the newer GT's have a returnless fuel system (Doesn't effect power though).

Mercury · 03-07-2002, 02:03 PM

The cams are also diffrent. Less Lift, longer duration. Oh, a quick question. Why do the duration of the intake side of the Cams differ from one cylinder bank to another?

I might be answering my own question, but I'm thinking it may be because of the intake, there trying to equal out intake flow.

Mustang92 · 03-07-2002, 02:18 PM

Actually the cams are the same for both heads. They have a split duration between intake and exhaust. So the exhaust valves with .540 duration will stay open longer than the intake valves at .510.

Basically the difference in the cars is the heads/cams.

Bill

03-07-2002, 08:50 AM	#1
surfbeast Registered Member Join Date: Feb 2002 Location: Maryville,TN Posts: 415	HP Differences Anyone know what the difference is between the 99 and up GT with 260hp and the 98 GT with only 225 hp. What did they do to get the extra 35 hp? Thanks! __________________ 98 GT / convertable -98 Saleen engine, Saleen appearance pkg. SHM cams,P&P NPI heads, and so much more!

03-07-2002, 10:20 AM	#2
SLOW 97 Registered Member Join Date: Feb 2002 Location: Arlington Heights,IL Posts: 231	The '99- up GT's have what are called PI (Power Improved, Product Improved, whatever you think it stands for) heads. These heads flow considerably better than the non-PI heads on my car. The intake manifold is also slightly different on the '99-up's. Another difference is the newer GT's have a returnless fuel system (Doesn't effect power though). __________________ '97 Laser Red GT Coupe Stock 2V (Pulled Silencer) 4R70W Automatic Ripped off a BLISTERING 15.37@90MPH With a 2.21 60ft Just Installed- K&N Air Filter Coming Soon...... -4.10's -Flowmaster A/T or Magnapack Cat-Back

03-07-2002, 02:03 PM	#3
Mercury The Redneck James Bond Join Date: Sep 2000 Location: Fayetteville NC Posts: 1,707	The cams are also diffrent. Less Lift, longer duration. Oh, a quick question. Why do the duration of the intake side of the Cams differ from one cylinder bank to another? I might be answering my own question, but I'm thinking it may be because of the intake, there trying to equal out intake flow. __________________ 64 1/2 "D" code Red Mustang Coupe. Red Baron, 2000 Perf Red Mustang GT. 5spd. Stage 2 CNC heads with Large Valves, Comp Cams (270-274 dur .550 lift), Forged Crank, DRP pistons, Manly H-beams, Pro M 87 mm Mass Air, 24lb Inj, 75mm TB, Plenum Spacer ,Long Tube Headers, Homemade H-pipe, 2 chamber Flows, 4:10's, Steeda Tri-Ax, LKW 70/30's, Eibach Drag Springs, Steeda SubFrames, Battle Boxes, Rear Girdle, Adj uppers, Alunimum Drshft, Southside Lift Bars. Project Cars, 64 1/2 6cyl coupe, 1930 Model A Nostalgia Rod.

03-07-2002, 02:18 PM	#4
Mustang92 Drag Racer! Join Date: Nov 1999 Location: Lake Worth, FL USA Posts: 757	Actually the cams are the same for both heads. They have a split duration between intake and exhaust. So the exhaust valves with .540 duration will stay open longer than the intake valves at .510. Basically the difference in the cars is the heads/cams. Bill __________________ 2000 GT VRS O/R X, Dynomax Bullets, Steeda Pulleys, Pro-M 80MM, 4.30s, UPR Pro Series Suspension, UPR Tubular K-member, MAC Longtubes, Bullitt Intake, TKO, VT Engine Stage 1 NA Cams, SCT Tune. 285 RWHP/296 RWTQ 11.97 @ 113.20 M/M 100, 7085 www.uprproducts.com www.ponyexpressperformance.com www.modulardepot.com

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