What system to buy for 0-75 mph perf. (WHY does back pressure "generate" torque?)
Thread Starter
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Senior Member
Joined: Mar 2000
Posts: 114
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From: CHULA VISTA, CA
What system to buy for 0-75 mph perf. (WHY does back pressure "generate" torque?)
My super Crew 5.4 has dual cats and then goes through a Y-pipe into a giant can of a muffler and out. All piping is the same size and I'd guess it was 2.5" or maybe 2.75-3.00". Are previous models equipped w/dual cats?
I have always thought that front to rear duals were the highest performance exhausts. (I am a classic Mustang owner.) I want 0-75mph performance and will never tow a horse/RV trailer all day, just an occaisional boat haul to the river/launch. (But my truck has to sound good enough to turn my classic Mustang friends green with envy.)
So, my questions are:
1) HOW does an engine "generate" torque by having back pressure pushing a piston down when the valve opens? It just doesn't figure to me. Is it something to do with the long duration of exhaust open (where low rpms allow the gas pressure time to act on the piston) ?
2) For my desired 0-75mph performance (and great sound), is a flowmaster 40/50 series single in/dual out directly replacing the stock can the best way to go? If this 0-60 single pipe stuff is true; this seems to be the way to go.
3) Is the Flowmaster's dual output routed to each side or do both tailpipes run parallel out the same side.
4) Is the 50 series too much quieter than the 40 series. I really want a neighborly idle and a ballsy throaty acceleration sound.
FYI. When K&N get their C.A.R.B. numbers for 2001, I plan to add their FIPK and also will drop in the superchip. Exhaust is mod number three.
Thanks to all for the great posts,
Joe
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2001 SuperCrew 4x4 Lariat 5.4/4-spd auto, 3.55 l/s, elec xfer case, Skids, Class III tow, Stock 17"s, Oxford White/Med Graphite leather capts chairs, Rhinolined
Planned: K&N FIPK (When they get the CARB # for 2001's), Superchip
I have always thought that front to rear duals were the highest performance exhausts. (I am a classic Mustang owner.) I want 0-75mph performance and will never tow a horse/RV trailer all day, just an occaisional boat haul to the river/launch. (But my truck has to sound good enough to turn my classic Mustang friends green with envy.)
So, my questions are:
1) HOW does an engine "generate" torque by having back pressure pushing a piston down when the valve opens? It just doesn't figure to me. Is it something to do with the long duration of exhaust open (where low rpms allow the gas pressure time to act on the piston) ?
2) For my desired 0-75mph performance (and great sound), is a flowmaster 40/50 series single in/dual out directly replacing the stock can the best way to go? If this 0-60 single pipe stuff is true; this seems to be the way to go.
3) Is the Flowmaster's dual output routed to each side or do both tailpipes run parallel out the same side.
4) Is the 50 series too much quieter than the 40 series. I really want a neighborly idle and a ballsy throaty acceleration sound.
FYI. When K&N get their C.A.R.B. numbers for 2001, I plan to add their FIPK and also will drop in the superchip. Exhaust is mod number three.
Thanks to all for the great posts,
Joe
------------------
2001 SuperCrew 4x4 Lariat 5.4/4-spd auto, 3.55 l/s, elec xfer case, Skids, Class III tow, Stock 17"s, Oxford White/Med Graphite leather capts chairs, Rhinolined
Planned: K&N FIPK (When they get the CARB # for 2001's), Superchip
Thread Starter
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Senior Member
Joined: Mar 2000
Posts: 114
Likes: 0
From: CHULA VISTA, CA
For anyone interested, I found this rice grinder article quite informative...but doesn't really complete the picture for me. I'd still love to get some good info from you folks!
http://www.geocities.com/MotorCity/7...usttheory.html
Joe
http://www.geocities.com/MotorCity/7...usttheory.html
Joe
Senior Member
Joined: Apr 1999
Posts: 276
Likes: 0
From: Tacoma, WA, USA
I haven't a clue about how backpressure can create torque but I might be able to help with your other questions...
Unless things have changed the pipe size from the Y to the muffler and the tail pipe is 2.5". My 98 4.6L was equipped with 4 cats leading into the Y, that huge muffler and single exit behind the wheel.
I went to a local speed shop (http://www.pro-max.com) for my Flowmaster installation. In selecting what I wanted I told them I did not want to lose the low end torque, I did not want it to resonate in the cab, I did not want it too loud - I wanted it to generate the sound of the late model Mustang GT's.
They installed a Flowmaster Deltaflow muffler (2.5"inlet - 3"outlet, Part number 942553) and 3" pipe to behind the wheel. They bent the pipe themselves.
It was exactly what I wanted. At idle it 'burbles' (best word I could find to describe it), under heavy acceleration it roars, at a steady 70 you hear a distinct low hum. It's not obnoxious - but it has presence.
I haven't noticed either a performance gain or loss. But I sure do enjoy the sound.
So, to answer your questions directly:
1 - I don't know. So many people have told me that in order not to lose low-end torque keep the pipe(s) diameter small.
2 - single-in, dual-out or single-in, bigger single-out in my mind is a matter of personal preference.
3 - If you buy Flowmaster's packaged cat-back system you'll get dual-out the back. If you go to a shop that can make their own bends they can do pretty much anything you want (and quite a bit cheaper I might add - mine was only $145 including a 3.5"x12" chrome tip).
4 - Whichever series you go with, it sounds to me like you should investigate Flowmaster's 'Deltaflow' technology equipped mufflers. It is a sound-cancelling technology that reduces decible levels without unnecessarily increasing backpressure.
Good luck with your new Supercrew - and go get that Superchip - it's the biggest bang for the buck!
Tom in Tacoma
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1998 F150 XLT S/C 4.6L Auto, 3.55LS, 4X2, Moonlight Blue, all the factory bells & whistles except for leather seats. Lund Deflector, Lund Premier Tonneau, K&N, Body-color painted Throttle Cover, blue wire-looms, Pentaliner S/R, Window tint, factory side-steps, Infiniti component speakers up front, Polk Audio speakers in back, Superchip, Flowmaster 'Delta-Flow' w/ 3" pipe, Clear turn signal lenses. Next up - billet grill. Tom in Tacoma (Washington not Toyota)
Go check out http://communities.msn.com/SS97FordsPics for the second best website for F150's
Unless things have changed the pipe size from the Y to the muffler and the tail pipe is 2.5". My 98 4.6L was equipped with 4 cats leading into the Y, that huge muffler and single exit behind the wheel.
I went to a local speed shop (http://www.pro-max.com) for my Flowmaster installation. In selecting what I wanted I told them I did not want to lose the low end torque, I did not want it to resonate in the cab, I did not want it too loud - I wanted it to generate the sound of the late model Mustang GT's.
They installed a Flowmaster Deltaflow muffler (2.5"inlet - 3"outlet, Part number 942553) and 3" pipe to behind the wheel. They bent the pipe themselves.
It was exactly what I wanted. At idle it 'burbles' (best word I could find to describe it), under heavy acceleration it roars, at a steady 70 you hear a distinct low hum. It's not obnoxious - but it has presence.
I haven't noticed either a performance gain or loss. But I sure do enjoy the sound.
So, to answer your questions directly:
1 - I don't know. So many people have told me that in order not to lose low-end torque keep the pipe(s) diameter small.
2 - single-in, dual-out or single-in, bigger single-out in my mind is a matter of personal preference.
3 - If you buy Flowmaster's packaged cat-back system you'll get dual-out the back. If you go to a shop that can make their own bends they can do pretty much anything you want (and quite a bit cheaper I might add - mine was only $145 including a 3.5"x12" chrome tip).
4 - Whichever series you go with, it sounds to me like you should investigate Flowmaster's 'Deltaflow' technology equipped mufflers. It is a sound-cancelling technology that reduces decible levels without unnecessarily increasing backpressure.
Good luck with your new Supercrew - and go get that Superchip - it's the biggest bang for the buck!
Tom in Tacoma
------------------
1998 F150 XLT S/C 4.6L Auto, 3.55LS, 4X2, Moonlight Blue, all the factory bells & whistles except for leather seats. Lund Deflector, Lund Premier Tonneau, K&N, Body-color painted Throttle Cover, blue wire-looms, Pentaliner S/R, Window tint, factory side-steps, Infiniti component speakers up front, Polk Audio speakers in back, Superchip, Flowmaster 'Delta-Flow' w/ 3" pipe, Clear turn signal lenses. Next up - billet grill. Tom in Tacoma (Washington not Toyota)
Go check out http://communities.msn.com/SS97FordsPics for the second best website for F150's