AFM Web

Go Back   Ford Mustang Forums > Mustang Forums > 2005 + Mustang > 2005+ Mustang GT Tech
Welcome to AllFordMustangs.com. We look forward to you registering on our forum and making your first post.
 
Introductions | Lounge | 2005+ GT Tech | 2005+ V6 Tech | 2005+ Talk | Mustang Tech | Racing | Regional 
 

Reply
 
Old 05-29-2009   #1 (permalink)
dabadee is offline Apprentice


Joined: Oct 2008
Posts: 58 Threads: 17
 dabadee's Country Flag  View dabadee's 10 photos
Lafayette   Louisiana
Default can lack of backpressure lead to burnt exhaust valves

i have heard from a couple of guys their concerns over lack of back pressure due to my install of the slp loudmouths. i know that several people put long tubes and high flow cats and xpipes that have to create little to no backpressure. can this create a problem or is it something that you have to tune for?
__________________
2005 GT Convertible Premium, Shaker 1000, Mycolor guages, 5spd manual (1 of 428 produced in 2005) SLP Loudmouth Axle Back, JLT II CAI, Bama 93 Race Tune, Boss Vinyl Stripe Kit, Shelby polished Hood Pins
dabadee is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-29-2009   #2 (permalink)
ITLRUN is offline Made Member

Classic Member
4.6L Member
5.0L Member


Joined: Jan 2008
Posts: 1,270 Threads: 2
 ITLRUN's Country Flag  View ITLRUN's 60 photos
Fall River   Massachusetts
Default

First off, can you hear yourself think with that exhaust? Second, yeah lack of back pressure can lead to a burnt exhaust valve. Any good free flowing catted X pipe, will give you sufficient back pressure with the right cat-back exhaust system, Mike. SCT Tuner.
ITLRUN is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-29-2009   #3 (permalink)
TheKurgan is offline Made Member

S197 Member


Joined: Jun 2008
Posts: 1,242 Threads: 17
 TheKurgan's Country Flag  View TheKurgan's 17 photos  View TheKurgan's HomePage
Little Rock   Arkansas
Send a message via Yahoo to TheKurgan
Default

Interesting. How many burnt exhaust valves on a mod motor have you seen due to no mufflers ? I've had mine off since practically day one and no issues.
__________________
It's better to burn out than to fade away - The Kurgan
TheKurgan is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-29-2009   #4 (permalink)
oldlugs is offline Made Member

S197 Member


Joined: Dec 2008
Posts: 288 Threads: 12
 oldlugs's Country Flag  View oldlugs's 16 photos
Los Angeles   California
Default

Lack of some back-pressure means a better flowing exhaust. It can create a leaner mixture condition, unless corrected for. The better the exhaust flows, the more air/fuel that can be pumped through, and more HP made. It does not lead to burned valves, unless your computer can't correct for the leaner mixture.
__________________
'08 Bullitt -Highland Green
'09 GT-500KR -Black/Black
oldlugs is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-29-2009   #5 (permalink)
stlwagon is online now Site Administrator

S197 Member


Joined: Oct 2005
Posts: 86,526 Threads: 674
 stlwagon's Country Flag  View stlwagon's 47 photos  View stlwagon's 4 classified ads
Southern   Maryland
Send a message via Yahoo to stlwagon
Default

I've never seen this happen on a modular motor.
__________________
AFM Site Administrator
2005 Mustang GT
stlwagon is online now  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-29-2009   #6 (permalink)
PLstang is offline Senior Member

4.6L Member
S197 Member


Joined: Jun 2008
Posts: 2,737 Threads: 61
 PLstang's Country Flag  View PLstang's 14 photos
Houston   Texas
Default

+1 me neither..
__________________
2007 Mustang GT Vista Blue
740RWHP/motor 904RWHP/spray
9.01 @ 152 mph 1/4 mile, 1.40 60'
2008 Clash of the Titans World Finals Champion
2009 Strictly Street Points leader/ET & MPH Record Holder

2009 GT500 Grabber Orange Vert 594 RWHP
11.5 @ 120mph it's my slow car!
PLstang is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-29-2009   #7 (permalink)
travelers is offline Top Dog

S197 Member


Joined: Sep 2006
Posts: 10,043 Threads: 64
 travelers's Country Flag  View travelers's 14 photos
Eastern   Pennsylvania
Default

If you were running a DD with open headers I might think about it. But with that long an exhaust system you don't have anything to worry about.
__________________
07 REDFIRE GT 5 SPEED 3.55 gears
C&L Racer CAI XCAL2/Seq signals/GTAs/Steeda UDP/CHE K Member Brace W/Torq Links/J&M LCA/Spider DS/PRO.50 Shifter Hurst handle & "T"/Meziere EO2/ARH LT catted H /Prothane MM/Delet Plates/SLP BOSS 429 Scoop/Accel COP/PowerSlot/Hawk Pads/Tokico D-Spec/CHE Panhard Bar Brace/Steeda Adj. Panhard Bar/BMR F/R Sway Bars/Cervini ducktail spoiler/BMR UCA Mount/CHE UCA/GT\CS Rear Cover/AMChrome Bullets 18x9/10s/Nitto 255/45&295/45
Tillman Dyno Tune 307HP/322TQ
travelers is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-30-2009   #8 (permalink)
BKid is offline Top Dog

S197 Member


Joined: Jan 2008
Posts: 4,916 Threads: 148
 BKid's Country Flag  View BKid's 14 photos
Rio Rancho   New Mexico
Default

I would be more worried about crapy gas. I have O/r x and not 1 problem.
__________________
Airraid CAI/BAMA tune,moto blue pullies,3:73`s,LPW girdle;Powerhouse DS,CHE safety loop,CHE LCA`S & Adjustable UCA,Kooks LT`S & O/R X Pipe,prothane MM`s,Steeda CMDP`S,Eibach springs,Tokico D specs,Polished TB(by Me),Steeda radiator support,MT DR`S,Zex kit 100 shot. Taylor Relocation batter kit and cut off switch
11:933 ET, 1.674 60`,111.877 MPH
BKid is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 05-30-2009   #9 (permalink)
stlwagon is online now Site Administrator

S197 Member


Joined: Oct 2005
Posts: 86,526 Threads: 674
 stlwagon's Country Flag  View stlwagon's 47 photos  View stlwagon's 4 classified ads
Southern   Maryland
Send a message via Yahoo to stlwagon
Default

Quote:
Originally Posted by travelers View Post
If you were running a DD with open headers I might think about it. But with that long an exhaust system you don't have anything to worry about.
Open headers in freezing temps maybe.
__________________
AFM Site Administrator
2005 Mustang GT
stlwagon is online now  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 06-04-2009   #10 (permalink)
VICMARTINEZ05 is offline Rookie


Joined: May 2009
Posts: 2 Threads: 0
 VICMARTINEZ05's Country Flag
HOUSTON   Texas
Default

SLP RULES! I love mine!
VICMARTINEZ05 is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 06-06-2009   #11 (permalink)
FREAKNAZTY is offline Made Member

S197 Member


Joined: Mar 2008
Posts: 897 Threads: 33
 FREAKNAZTY's Country Flag  View FREAKNAZTY's 12 photos
Chauvin   Louisiana
Send a message via Yahoo to FREAKNAZTY
Default

Quote:
Originally Posted by dabadee View Post
i have heard from a couple of guys their concerns over lack of back pressure due to my install of the slp loudmouths. i know that several people put long tubes and high flow cats and xpipes that have to create little to no backpressure. can this create a problem or is it something that you have to tune for?
i have run stock h-pipe with loudmouths , off-road h with loudmouths , and a powerhouse turbo with loudmouths so all in all 3 setups and about a years worth of beating on it never had a one problem with burning valves , someone is blowing smoke up your .........

and believe me if anyone can break a part it's me
__________________
TOO MUCH TO LIST ......NOT ENOUGH TO BRAG ABOUT
FREAKNAZTY is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 06-06-2009   #12 (permalink)
Tominator is offline Senior Member

5.0L Member


Joined: Nov 2003
Posts: 2,453 Threads: 73
 Tominator's Country Flag  View Tominator's 26 photos
Cahokia   Illinois
Default

Quote:
Originally Posted by stlwagon View Post
I've never seen this happen on a modular motor.
It can't happen!

That's an 'old mechanics tale' based on years of misinformation.

Yes, it would be a lean mixture that could lead to valve failure, but I do not believe that a 'lack of back pressure will burn valves.'
Tominator is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 06-06-2009   #13 (permalink)
GAP
GAP is offline Apprentice


Joined: Aug 2008
Posts: 87 Threads: 4
 GAP's Country Flag
Euless   Texas
Default

Sounds more like poorly tuned motors which are running lean burning valves. Whether or not that was due to a installing a free flowing exhaust is irrelevant, still goes back to the A/F tune.
GAP is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Old 06-06-2009   #14 (permalink)
One_Quik_Pony is offline Made Member

5.0L Member


Joined: Dec 2002
Posts: 382 Threads: 14
 One_Quik_Pony's Country Flag  View One_Quik_Pony's 9 photos
Phoenix   Arizona
Default

An absolute lack of exhaust components, such as running huge open headers, or no manifolds at all, could have caused burned exhaust valves due to the temperature differential between the cylinder temps and ambient air...but still highly unlikely.

Maybe somebodys uncle or grandfather ran a street-stock stock car with no manifolds, and burned a valve...just my guess.
__________________
After building Porsches, I now realize how elementary American cars really are!
One_Quik_Pony is offline  
Digg this Post!Add Post to del.icio.usBookmark Post in TechnoratiFurl this Post!
Reply With Quote
Reply



Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Turbo vs. Supercharger Power Adders 143 06-14-2009 09:01 PM
Which valves are intake, which exhaust? jrtdreamliver 5.0L Tech 6 05-03-2008 01:19 AM
changing exhaust valves??? jason7482 5.0L Tech 3 09-24-2007 10:47 PM
2006 exhaust ?'s moose_knuckle 2005+ Talk 13 06-13-2006 04:04 PM
burnt exhaust valve marks86gt 5.0L Tech 1 02-25-2005 01:20 PM

sponsors

Mustang Photos
Add to Favorites    Link to us    Contact    Directory    Site Rules    Archive    Terms of Use    Privacy    Top Sites    RSS    Meet Our Sponsors    Advertise   
AllFordMustangs is not affiliated with or endorsed by Ford Motor Company. ©Copyright 2002-2010 All Auto Enthusiasts Network

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110