Realistic expectations

08-28-2001, 01:26 PM

I'm 99.9% sure I'll be going w/ a full exhaust swap as my next mod job: 1 5/8" or 1 3/4" MAC longtubes, MAC prochamber (2.5") or h-pipe, and 2.5" cat back. What improvements can I REALISTICALLY expect (hp gain, 1/4 time, sound)????
Thanks for your .02!

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'90 LX 5.0;12K original miles (no sh*&);3.55 gears; March pulleys;Edelbrock Performer Heads;BBK 1 5/8" equal length shorties;MSD 6AL ignition w/ blaster 2 coil;FMS E303 cam;Pro-M 75mm MAF;BBK 70mm TB; Eibach drag-launch spring kit;Southside welded subs;9" K&N cone filter charger;Hurst shifter;Cervini's 3" turbo hood;A/C delete; gutted cats;2 chamber Flomasters;Corbeau racing seats;FMS 30# injectors;JMS chip; Holley 190lb fp;TFS track heat Intake (12.299 @ 113 - 1.78 60')

fiveohpatrol · 08-28-2001, 01:37 PM

the sound will probably be the best improvement it makes, i wouldnt think it would give you more than 2 tenths, if that,because yours is already somewhat free-flowing

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88 Notch, B&M Ripper, 3.73's, Ported E7's, Explorer int. w/ ported lower, pulleys, 1.7RR's, BBK headers, off-road H-pipe, flowmasters, subframes, 65mm TB, March ram air ,MSD coil, U/L control arms, 155lph f/p, Crane Adj.FPR, Nitto drag radials, best 1/4--> 13.76@101.4 on a 2.17 60ft

dinomite · 08-28-2001, 03:09 PM

doing the long tubes and h-pipe, i think you will pick up a little bit, plus nice sound. maybe a tenth or so? i'd say get the 1 3/4" headers.

08-28-2001, 04:29 PM

That's exactly what I was thinking...awesome sound w/ the most .1-.15 quicker. Thanks guys. I've heard the pros and cons of 1 3/4 and 1 5/8......and I'm still pretty confused, except I'm probably leaning toward the 1 3/4. Anyone else?

Unit 5302 · 08-28-2001, 06:10 PM

Get the 1 5/8", they'll be better matched to your exhaust ports. If you had a 351, or a 347 stroker the 1 3/4 might be the way to go.

I'd expect you to pick up 3-4 tenths with those mods. The headers will probably give you 10hp, the prochamber H 20hp, and the rest of the exhaust will chime in a little too. More than that, you'll gain low end with the headers.

08-28-2001, 07:47 PM

Thanks Unit....wow, much more than I anticipate - hope you're right

------------------
'90 LX 5.0;12K original miles (no sh*&);3.55 gears; March pulleys;Edelbrock Performer Heads;BBK 1 5/8" equal length shorties;MSD 6AL ignition w/ blaster 2 coil;FMS E303 cam;Pro-M 75mm MAF;BBK 70mm TB; Eibach drag-launch spring kit;Southside welded subs;9" K&N cone filter charger;Hurst shifter;Cervini's 3" turbo hood;A/C delete; gutted cats;2 chamber Flomasters;Corbeau racing seats;FMS 30# injectors;JMS chip; Holley 190lb fp;TFS track heat Intake (12.299 @ 113 - 1.78 60')

Skyman · 08-29-2001, 02:54 AM

Unit, look how much HP his car is making 113 traps, and I believe it dynoed 330+ RWHP, am I correct? I believe thats more than enough HP for the larger exhaust.

Skyler

------------------
-1989 Saleen Mustang #406-
TFS TW Heads, E-303, Edelbrock intake, 70mm TB, 73mm MAF, 24lb injectors, 1 5/8 shorties, Off Road H, 3 Chamber flows, Jaz Race seats, Back seat removed, sub-frames, Roll Cage, and a 80 shot of N20.
12.54@107.4 Motor
332RWHP, 350rwtq

08-29-2001, 04:47 PM

Yeah Sky, it's at 341 right now. I really value your .02, everyone elses too, but I keep getting so many different opinions (I guess that's why I'm so *******' confused). I've heard that 1 5/8 and 2 1/2 set up is all that's needed up to 600 hp, etc, etc. If anyone has more comments, I'd appreciate them, eve if I get more confused and have to rely on an eenie-meenie-minie-mo to pick the parts

Thanks for all your comments......keep 'em comin'.

Unit 5302 · 08-29-2001, 07:13 PM

Quote:

Originally posted by Skyman:
Unit, look how much HP his car is making 113 traps, and I believe it dynoed 330+ RWHP, am I correct? I believe thats more than enough HP for the larger exhaust.

Skyler

I agree with the fact his car is flying. Going to bigger exhaust is going to mess with the L/T's in my opinion. Long tubes develop a fully tuned effect, blocking off the cylinder when it's on intake, and tuning it when it's on exhaust. Kinda like a snowmobile exhaust. Getting bigger primary's might increase tuning at higher rpms, but with the extra volume size of the runners, approx 10%, and the uneven header to head size ports, I think he'll lose some of the proper tuning created by the long tubes. If he had a bigger exhaust port, then I'd say he might want the 1 3/4" exhaust.

Just my opinion.

08-30-2001, 04:11 PM

Guys, I REALLY appreciate all the help.......if I could I'd like to slip in another questions: would going w/ a 3" cat back after the 2 1/2" powerchamber h-pip do anything adverse to my performance? I only ask, cause if it wouldn't, I think it'd look cool w/ a bigger pipe out the rear (not to get too "ricer" either)

Thanks!

08-28-2001, 01:26 PM	#1
bada$$lx Guest Posts: n/a	Realistic expectations I'm 99.9% sure I'll be going w/ a full exhaust swap as my next mod job: 1 5/8" or 1 3/4" MAC longtubes, MAC prochamber (2.5") or h-pipe, and 2.5" cat back. What improvements can I REALISTICALLY expect (hp gain, 1/4 time, sound)???? Thanks for your .02! ------------------ '90 LX 5.0;12K original miles (no sh*&);3.55 gears; March pulleys;Edelbrock Performer Heads;BBK 1 5/8" equal length shorties;MSD 6AL ignition w/ blaster 2 coil;FMS E303 cam;Pro-M 75mm MAF;BBK 70mm TB; Eibach drag-launch spring kit;Southside welded subs;9" K&N cone filter charger;Hurst shifter;Cervini's 3" turbo hood;A/C delete; gutted cats;2 chamber Flomasters;Corbeau racing seats;FMS 30# injectors;JMS chip; Holley 190lb fp;TFS track heat Intake (12.299 @ 113 - 1.78 60')

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08-28-2001, 01:37 PM	#2
fiveohpatrol I'd rather be basketweaving Join Date: Feb 2000 Location: Indianapolis Posts: 2,551	the sound will probably be the best improvement it makes, i wouldnt think it would give you more than 2 tenths, if that,because yours is already somewhat free-flowing ------------------ 88 Notch, B&M Ripper, 3.73's, Ported E7's, Explorer int. w/ ported lower, pulleys, 1.7RR's, BBK headers, off-road H-pipe, flowmasters, subframes, 65mm TB, March ram air ,MSD coil, U/L control arms, 155lph f/p, Crane Adj.FPR, Nitto drag radials, best 1/4--> 13.76@101.4 on a 2.17 60ft

08-28-2001, 03:09 PM	#3
dinomite The Dude Join Date: Feb 2001 Location: Arlington, VA Posts: 1,262	doing the long tubes and h-pipe, i think you will pick up a little bit, plus nice sound. maybe a tenth or so? i'd say get the 1 3/4" headers.

08-28-2001, 04:29 PM	#4
bada$$lx Guest Posts: n/a	That's exactly what I was thinking...awesome sound w/ the most .1-.15 quicker. Thanks guys. I've heard the pros and cons of 1 3/4 and 1 5/8......and I'm still pretty confused, except I'm probably leaning toward the 1 3/4. Anyone else?

08-28-2001, 06:10 PM	#5
Unit 5302 Registered Member Join Date: May 1999 Posts: 5,246	Get the 1 5/8", they'll be better matched to your exhaust ports. If you had a 351, or a 347 stroker the 1 3/4 might be the way to go. I'd expect you to pick up 3-4 tenths with those mods. The headers will probably give you 10hp, the prochamber H 20hp, and the rest of the exhaust will chime in a little too. More than that, you'll gain low end with the headers.

08-28-2001, 07:47 PM	#6
bada$$lx Guest Posts: n/a	Thanks Unit....wow, much more than I anticipate - hope you're right ------------------ '90 LX 5.0;12K original miles (no sh*&);3.55 gears; March pulleys;Edelbrock Performer Heads;BBK 1 5/8" equal length shorties;MSD 6AL ignition w/ blaster 2 coil;FMS E303 cam;Pro-M 75mm MAF;BBK 70mm TB; Eibach drag-launch spring kit;Southside welded subs;9" K&N cone filter charger;Hurst shifter;Cervini's 3" turbo hood;A/C delete; gutted cats;2 chamber Flomasters;Corbeau racing seats;FMS 30# injectors;JMS chip; Holley 190lb fp;TFS track heat Intake (12.299 @ 113 - 1.78 60')

08-29-2001, 02:54 AM	#7
Skyman I need 110mph Trap Speed! Join Date: Feb 1999 Location: So, CA Posts: 4,315	Unit, look how much HP his car is making 113 traps, and I believe it dynoed 330+ RWHP, am I correct? I believe thats more than enough HP for the larger exhaust. Skyler ------------------ -1989 Saleen Mustang #406- TFS TW Heads, E-303, Edelbrock intake, 70mm TB, 73mm MAF, 24lb injectors, 1 5/8 shorties, Off Road H, 3 Chamber flows, Jaz Race seats, Back seat removed, sub-frames, Roll Cage, and a 80 shot of N20. 12.54@107.4 Motor *332RWHP, 350rwtq*

08-29-2001, 04:47 PM	#8
bada$$lx Guest Posts: n/a	Yeah Sky, it's at 341 right now. I really value your .02, everyone elses too, but I keep getting so many different opinions (I guess that's why I'm so *******' confused). I've heard that 1 5/8 and 2 1/2 set up is all that's needed up to 600 hp, etc, etc. If anyone has more comments, I'd appreciate them, eve if I get more confused and have to rely on an eenie-meenie-minie-mo to pick the parts Thanks for all your comments......keep 'em comin'.

08-30-2001, 04:11 PM	#10
bada$$lx Guest Posts: n/a	Guys, I REALLY appreciate all the help.......if I could I'd like to slip in another questions: would going w/ a 3" cat back after the 2 1/2" powerchamber h-pip do anything adverse to my performance? I only ask, cause if it wouldn't, I think it'd look cool w/ a bigger pipe out the rear (not to get too "ricer" either) Thanks!