running a truck without headers/exhaust? - Pirate4x4.Com : 4x4 and Off-Road Forum
 
Pirate4x4.Com : 4x4 and Off-Road Forum  

Go Back   Pirate4x4.Com : 4x4 and Off-Road Forum > General Tech > Newbie General 4x4 Discussion
Notices

Reply
 
Share Thread Tools Display Modes
Old 09-07-2006, 12:29 PM   #1 (permalink)
Registered User
 
Join Date: Jul 2006
Member # 76389
Posts: 105
running a truck without headers/exhaust?

besides the noise, is there anything wrong with running a truck without any pipes? got my truck running but i don't have an exhaust for it right now and want to take it around the block to make sure everything is running right. could i damage anything? neighbor said i could burn the valves but i don't see how snapping an exhaust on would stop that
Neren is offline   Reply With Quote
Old 09-07-2006, 12:40 PM   #2 (permalink)
Registered User
 
Join Date: Jul 2006
Member # 74903
Posts: 356
He is correct, because with the exhaust on there is a certain amount of back pressure that is applied to the engine.....exhaust isnt just for noise...also depending on the year it isnt going to run right because you will not have your O2 sensor hooked up....
tikitgvr is offline   Reply With Quote
Sponsored Links
Old 09-07-2006, 12:43 PM   #3 (permalink)
Registered User
 
Join Date: Jul 2005
Member # 50360
Location: Mount Carmel, PA.
Posts: 1,634
Send a message via AIM to NetBSD Send a message via Yahoo to NetBSD
we did this on a 89 amigo 2.6L, we just put a new frame under it and new block, fired it up with only the manifold and a 12" pipe on it, ran it maybe 5 miutes with no problems just to make sure it ran right, but from what im told if you dont run a pip or manifold youll warp the heads or something
__________________
89 Ranger, 2.9, 6" lift, 35" baja claws
92 Silverado, 6.2L, GM-3 Turbo at 10PSI
NetBSD is offline   Reply With Quote
Old 09-07-2006, 01:06 PM   #4 (permalink)
Registered User
 
Join Date: May 2005
Member # 47246
Location: Greenville NH
Posts: 466
Send a message via AIM to NHRedneck
ive been running my truck around the yard for a month or 2 and its got holy headers and no exhaust...... if the motor is bone stock i wouldnt reccomend running it for very long without a muffler for back pressure... I wouldnt ever run a motor without a set of headers on it though..... it would be one hell of a flame show and that def isnt good for the valves....... if the motor has some work i wouldnt worry about it too much....
__________________
Mud DriverI: 79 F150 built 400M, 35x14.5x15 boggers, 4" lift, 9"R, D44 F, NP435, NP203 : [url]http://www.cardomain.com/ride/2145548[/url]
Mud DriverII: 77 F250 stock 400M, 36x12.5x16.5 TSL's, highboy, D60 R,D44F HD , NP435, np205 : [url]http://www.cardomain.com/ride/393604[/url]
NHRedneck is offline   Reply With Quote
Old 09-07-2006, 01:42 PM   #5 (permalink)
Registered User
 
tennessee rockhumper's Avatar
 
Join Date: Aug 2005
Member # 52201
Location: fixing my junk so i can go break it
Posts: 630
if you are running zero exhaust, on manifold, header, exhaus ect...
the lack of back pressure wont ruin the engine. the cold air that hits the valves when you turn it off will warp the shit out of things.
tennessee rockhumper is offline   Reply With Quote
Old 09-07-2006, 02:19 PM   #6 (permalink)
Registered User
 
Join Date: May 2005
Member # 47826
Location: PISMO BEACH
Posts: 1,052
X2 warped valves. if you run it... it gets warm... then the cold air gets in the exhaust ports and the material (valves) warps.
__________________
Thean Bellocchi

[URL="www.polyperformance.com"]www.[COLOR="Red"][B]P[/B][/COLOR]oly[COLOR="Red"][B]P[/B][/COLOR]erformance.com[/URL]

[email]Thean@PolyPerformance.com[/email]

Last edited by crusty1007; 09-07-2006 at 02:22 PM.
crusty1007 is offline   Reply With Quote
Old 09-07-2006, 02:48 PM   #7 (permalink)
Registered User
 
Join Date: Mar 2006
Member # 70402
Location: San Antonio, Texas
Posts: 1,368
What kind of vehicle is this? Also what exactly do you mean by no exhaust? I think these are neccesary questions before you can get some good advice on it.
nooblet is offline   Reply With Quote
Old 09-07-2006, 06:22 PM   #8 (permalink)
Registered User
 
Join Date: Jul 2006
Member # 76389
Posts: 105
truck is a 1985 toyota with an 81 engine. i have ran it for about 3 mins altogether combined from turning it on about 4 times or so
Neren is offline   Reply With Quote
Old 09-08-2006, 06:37 AM   #9 (permalink)
Registered User
 
Join Date: May 2006
Member # 73059
Location: Chattanooga tn/Ellijay Ga
Posts: 948
Quote:
Originally Posted by tennessee rockhumper
the cold air that hits the valves when you turn it off will warp the shit out of things.
You know I'v heard that all my life, But what about racing engines that only have short zoomes or header onlys???????
Rockhales is offline   Reply With Quote
Old 09-08-2006, 07:22 AM   #10 (permalink)
Registered User
 
Join Date: Oct 2004
Member # 36399
Location: Hinesburg, VT
Posts: 3,147
Quote:
Originally Posted by Rockhales
You know I'v heard that all my life, But what about racing engines that only have short zoomes or header onlys???????
they are holding in enough heat where cold air doesnt directly hit the valves etc.

And again exhaust has nothing to do with back pressure. Back pressure is evil..you really dont want it.
__________________
94 F-150 Stepside. BGTL 12" lift, 1-tons, 39" 'roks
95 F-150 6" of lift, SAS 35" BFG's
94stepsideford is offline   Reply With Quote
Old 09-08-2006, 06:31 PM   #11 (permalink)
Registered User
 
Join Date: Dec 2003
Member # 24992
Location: Sch. Hvn., PA
Posts: 151
Quote:
Originally Posted by tennessee rockhumper
if you are running zero exhaust, on manifold, header, exhaus ect...
the lack of back pressure wont ruin the engine. the cold air that hits the valves when you turn it off will warp the shit out of things.
Now that makes some sense. I've heard people say you couldn't do it because of not having any backpressure, but I could never really see how that could possibly hurt anything. Burning valves never made sense either because how could it possibly be hotter without exhaust then with. Cold air hitting the valves and cooling them too quickly and making them warp makes alot more sense. Even just having a manifold attached would hold enough heat and trap the hot air keeping things from cooling off right away.
__________________
5.9 ZJ on 31's - Wife's DD.
'94 YJ - RE 4.5XD, 1" BL, Waggy 44's, 4.88's, ARB's & 35's.
SteveZ59 is offline   Reply With Quote
Old 09-08-2006, 07:28 PM   #12 (permalink)
Registered User
 
KiGrind's Avatar
 
Join Date: Feb 2006
Member # 66647
Location: Knoxville, TN
Posts: 1,323
Yeah well "Compression" horsecrap, there are enough vehicles on the road with 3" of worthless pipe running out to a flowmaster 40 and a crome tip with "TRUE DUEL" that never connects that prove you don't need it.
__________________
70 Jeepster Commando
95 ZJ
KiGrind is offline   Reply With Quote
Old 09-08-2006, 10:09 PM   #13 (permalink)
Registered User
 
Join Date: Feb 2006
Member # 67882
Location: Orange County
Posts: 2,387
He did this to a olds. just load and allmost burned all the wires but besides that no harm
__________________
120 fabrication
Two fj40s on 60s
fj40forlife is offline   Reply With Quote
Old 09-01-2013, 03:40 PM   #14 (permalink)
Registered User
 
Join Date: Jul 2013
Member # 335050
Location: colebrook nh
Posts: 0
its not back pressure its exhaust velocity the only danger is running without exhaust is on the intake stroke the exhaust valve may not be fully closed bringing in cold outside air warping or cracking a valve.
81jeepmutt is offline   Reply With Quote
Old 09-01-2013, 06:41 PM   #15 (permalink)
I See You
 
Provience's Avatar
 
Join Date: Jul 2009
Member # 138976
Location: Newport News, VA
Posts: 4,094
Quote:
Originally Posted by 81jeepmutt View Post
its not back pressure its exhaust velocity the only danger is running without exhaust is on the intake stroke the exhaust valve may not be fully closed bringing in cold outside air warping or cracking a valve.
Correct, but hopefully after 6 years he isn't still running it without exhaust!

Backpressure is required on a 2 stroke, not a 4...hence why smooth exhaust bends and polished ports are good on the exhaust side.
__________________
Up is difficult. Down is dangerous.

I Like Bright Colors

Romans 1:28-32

Matthews 7:15-20

John 14

Surah 109


For the best deal on 8 lug disc brakes click here--> www.lugnut4x4.com
Provience is offline   Reply With Quote
Old 09-03-2013, 11:05 AM   #16 (permalink)
Registered User
 
Join Date: Aug 2013
Member # 356162
Location: Oly, WA
Posts: 19
You need about 12" - 15" of pipe coming off of the headers on a stock or mild engine so that you don't suck cold air in and warp a valve. Also, yes, backpressure is evil on a 4 stroke.
__________________
The mind is the most powerful weapon.
CledusVanDamme is offline   Reply With Quote
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On



All times are GMT -7. The time now is 07:37 PM.


Powered by vBulletin® Version 3.8.6
Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.0 ©2011, Crawlability, Inc.