Open Exaust Good Or Bad?

JSFIRE79 · 12-18-2003, 05:00 PM

RUNNING THE 125 SHOT THROUGH GT-40HEADS AND INTAKE . WITH A NITROUS CAM, FULL FUEL SYSTEM AND SOME OTHER STUFF . DID I GAIN HORSE POWER OR LOSE IT WITH REDUCED BACK PRESSURE. I BASICALLY JUST RAN THE SHORTIES WITH THE 2 1/2 H-PIPE NO CATS AND NO MUFFLERS ( TILL I CAN AFFORD LONGTUBES) . IM SAFER W/ NITROUS W/ OPEN EXAUST RIGHT?

Dark_5.0 · 12-18-2003, 05:53 PM

If you are spraying backpressure isnt your friend.

Open pipes and nitrous are good

JSFIRE79 · 12-18-2003, 10:21 PM

I didnt think so.....thanx for help 5.0 .......What about on motor?

Jeff Chambers · 12-19-2003, 08:26 AM

I made some of my best passes this year with open exhaust. Back to back runs with my 2-1/2" Bassani X-pipe into Dynomax Race Magnum Bullets and then no exhaust were nearly a tenth apart. The X-pipe is nice for the street and building torque, but when the bulk of the pass is at more than 7000rpm, its just a bottleneck.

exgmguy · 12-19-2003, 03:00 PM

If you make the bulk of you power betweed 3500-6000 rpm, an open exhaust will probably hurt you.

I was spraying a dry 150 shot with turndowns, added tails and I swear the car felt slower. But I picked up 1 mph at the track. Go figure, loud does not mean fast.

ciara · 12-20-2003, 02:01 AM

My car launches at 3500 rpm and a shift at 6500 rpm. I had a set of extensions on my headers about 12" long. Sometimes I ran open headers, car was a little slower with open headers. Should I look into a race muffler or just run the extensions off of my headers? This is a drag only car.

12-18-2003, 05:00 PM	#1
JSFIRE79 Registered Member Join Date: Sep 2000 Location: Northridge, Ca. USA Posts: 27	Open Exaust Good Or Bad? RUNNING THE 125 SHOT THROUGH GT-40HEADS AND INTAKE . WITH A NITROUS CAM, FULL FUEL SYSTEM AND SOME OTHER STUFF . DID I GAIN HORSE POWER OR LOSE IT WITH REDUCED BACK PRESSURE. I BASICALLY JUST RAN THE SHORTIES WITH THE 2 1/2 H-PIPE NO CATS AND NO MUFFLERS ( TILL I CAN AFFORD LONGTUBES) . IM SAFER W/ NITROUS W/ OPEN EXAUST RIGHT? __________________ 93GT Stock 302, 170,000 miles....GT-40Y Heads, Ported and Extrude Honed GT-40 intake, Pro-M w/Granitelli Meter , 65mm Throttle Body , Custom Crane Cam, Rockers, lifters, pushrods, Mikes Transmissions Built AOD, 3000 stall, Aluminum Driveshaft , 3.73 gears, Motorsports shorty headers, Stock axles, ZEX 125HP kit. w/Bottle warmer. 60ft. - 1.60 1/4- 11.38 MPH- 119 WWW.StarkRacing.net

12-18-2003, 05:53 PM	#2
Dark_5.0 Registered Member Join Date: Apr 2001 Location: Staging lane Posts: 4,337	If you are spraying backpressure isnt your friend. Open pipes and nitrous are good __________________ 92' LX-Big brakes, Lots and lots of suspension, GT40X heads, Ported cobra intake, stock cam, Vortech SC trim. 00' Lightning-Stock 88'CRX-13 second ego killer

12-18-2003, 10:21 PM	#3
JSFIRE79 Registered Member Join Date: Sep 2000 Location: Northridge, Ca. USA Posts: 27	I didnt think so.....thanx for help 5.0 .......What about on motor? __________________ 93GT Stock 302, 170,000 miles....GT-40Y Heads, Ported and Extrude Honed GT-40 intake, Pro-M w/Granitelli Meter , 65mm Throttle Body , Custom Crane Cam, Rockers, lifters, pushrods, Mikes Transmissions Built AOD, 3000 stall, Aluminum Driveshaft , 3.73 gears, Motorsports shorty headers, Stock axles, ZEX 125HP kit. w/Bottle warmer. 60ft. - 1.60 1/4- 11.38 MPH- 119 WWW.StarkRacing.net

12-19-2003, 08:26 AM	#4
Jeff Chambers Moderator Join Date: Aug 2000 Location: Milan, OH Posts: 2,699	I made some of my best passes this year with open exhaust. Back to back runs with my 2-1/2" Bassani X-pipe into Dynomax Race Magnum Bullets and then no exhaust were nearly a tenth apart. The X-pipe is nice for the street and building torque, but when the bulk of the pass is at more than 7000rpm, its just a bottleneck. __________________ Jeff Chambers 1990 Mustang GT 10.032 Seconds / 137.5 MPH 14-time Street Warrior World Record Setter CRT Performance 2001 Tropic Green Mustang GT - 12.181 / 113.2 MPH 2002 Ford F-250 Crew Cab 7.3l Power Stroke - 17.41@77.2 "There's nothing boring about a small block automatic shifting gears at 9400 rpm!"

12-19-2003, 03:00 PM	#5
exgmguy Registered Member Join Date: Feb 1999 Location: Utica, Michigan Posts: 2,631	If you make the bulk of you power betweed 3500-6000 rpm, an open exhaust will probably hurt you. I was spraying a dry 150 shot with turndowns, added tails and I swear the car felt slower. But I picked up 1 mph at the track. Go figure, loud does not mean fast. __________________ 1988 Mustang GT stock bottom 302, C4 10.9 @ 128 with 8 psi of Novi 1000 boost!----STOLEN 1989 Mustang notchback Warmed up 306 with a Procharger.

12-20-2003, 02:01 AM	#6
ciara Registered Member Join Date: Jan 2002 Posts: 100	My car launches at 3500 rpm and a shift at 6500 rpm. I had a set of extensions on my headers about 12" long. Sometimes I ran open headers, car was a little slower with open headers. Should I look into a race muffler or just run the extensions off of my headers? This is a drag only car.

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