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Technical Bad to run straight pipes?

Discussion in 'The Hokey Ass Message Board' started by Fender1325, May 10, 2016.

  1. Fender1325
    Joined: Aug 31, 2014
    Posts: 730


    Over the years Ive heard and experienced mixed thoughts on exhaust, mainly running straight.

    The other day I took my 50 cad to a car show and the time I got back I had a bitching headache and it lasted the entire day, and my blood pressure was high. I believe it was CO2 poisoning from my leaky exhaust, and leaky valve covers smokin. So I said enough is enough I gotta fix this stuff.

    The exhaust is all rusted heavily, not exactly worth welding on. Me being the cheap bastard I am, Im thinking of sawzalling off the exhaust where its mainly bad (before the muffler) and getting some cheap exhaust pipe and clamps from autozone and running it out back.

    Ive heard straight exhaust can burn valves? Is that true?

    I also know from experience that some cars do better with a little back pressure for whatever odd reason. My old mustang (98) I used to run straight pipes for a little while and when I put in a catted midpipe it was quieter but seemed to pull better.

  2. indyjps
    Joined: Feb 21, 2007
    Posts: 4,038


    A straight pipe won't fit well under the car and will hang down, spend a little and get it bent up at a decent shop. As far as running a muffler or not, your call, won't hurt the engine, may need carb tuning, jet change.
  3. Slopok
    Joined: Jan 30, 2012
    Posts: 2,605


    A Caddy is supposed to be quiet.
    jkluge, Boryca, bobg1951chevy and 3 others like this.
  4. Fender1325
    Joined: Aug 31, 2014
    Posts: 730


    Id buy some angled pieces and go up over the axle. Plus this car has an X frame. The majority of the stock exhaust is straight, runs through the side of the X

  5. Fender1325
    Joined: Aug 31, 2014
    Posts: 730


    So is every car on this entire forum when it was stock from the factory.
    volvobrynk likes this.
    Joined: Jun 3, 2005
    Posts: 8,116


    A couple cheap high volume mufflers, run it right, think about adding an 'H' pipe too. The other option, run a single large pipe. Stock it was probably just under 2" so try to run 2 3/4" (like 90s GM 'F' bodies). The thinking behind the big single is performance and sound. Won't "rat-tat-tat" like straight pipes or glasspacks, mid range performance should be notable over open pipes. Think muffler from a 3/4-1 ton truck. Just sayin...
    HOTRODPRIMER and Nailhead Jason like this.
  7. If you want to run straight pipes do it but do it right,if your exhaust is shot replace it front to back,sometimes you just have to get off the wallet and spend what you have to. HRP
    Last edited: May 10, 2016
  8. Fender1325
    Joined: Aug 31, 2014
    Posts: 730


    My favorite exhaust note is from old chris craft boats.....

    I was originally going to run a porter muffler. They sound good with a 331 cad, but for some cheap fun, and to divert the fumes out back I was going to try straight pipes. Just wanted to make sure I wasnt hurting the engine
  9. Fender1325
    Joined: Aug 31, 2014
    Posts: 730


    Trust me guys if I had the wallet this old girl would have a lot more things replaced. Right now Im just trying to enjoy it and keep it rolling down the road.
  10. Cool Caddy!

    Forget about the "backpressure is needed" technical discussion and spend the money to get a full exhaust system.
    A crossover pipe and big "turbo" mufflers will give you the performance and quiet-but-healthy sound you're looking for.

    BTW, minor technical point:
    CO2 is Carbon Dioxide.
    CO is Carbon Monoxide and is probably what gave you the headache.
    BigChief, volvobrynk, stimpy and 3 others like this.
  11. Just be sure you avoid dihydrogen monoxide at all costs. It is EVERYWHERE!
  12. 2935ford
    Joined: Jan 6, 2006
    Posts: 3,454


    Speaking if CO.
    I have a monitor I use in my closed cars.
    Do not mess with CO.......that stuff is dangerous to your health!:)
    Last edited: May 10, 2016
    volvobrynk and HOTRODPRIMER like this.
  13. Blue One
    Joined: Feb 6, 2010
    Posts: 10,856

    Blue One
    from Alberta

    :rolleyes: It has already been pointed out that it is not CO2, but rather CO.

    The OP should not be so cheap and just replace the whole exhaust system properly.
    volvobrynk, stimpy, Just Gary and 2 others like this.
  14. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,093

    from So Cal

    The others have already covered it all, but I will second those that said to forget about the concerns of open pipes hurting the engine, or the engine needing exhaust back pressure, both of those are myths. Back pressure in the exhaust is never a good thing. What people are actually referring to is exhaust gas velocity, and tuning the exhaust system to match the engine power/torque curves so the velocity of the exhaust for best performance from that engine. Different engines are tuned for best performance at different rpm ranges, and you want the exhaust system to match the intake and cam characteristics for the best performance. Sometimes that means smaller diameter pipes to keep the velocity of the exhaust gasses up at a lower rpm, sometimes it means larger pipes to allow more flow at higher rpm's at the sacrifice of good velocity at low rpm's. It's always about scavenging the exhaust gas from the cylinders, it's never about back pressure in the system that prevents the exhaust gasses from exiting.
  15. Breathing the exhaust is not advantageous to you & your passengers health,especially if you have young children.

    I understand having a list of things you want to do,but you wouldn't drive the car with no brakes,I would hope you would spend the cash to fix the problem.

    There is always things you can cut back on to save money to repair your ride.if you like to partake in adult libations quit for a while,the same goes for smoking,heck back off on the cheese burgers.:D where there's a will,there's a way. HRP
  16. Fender1325
    Joined: Aug 31, 2014
    Posts: 730


    For my own knowledge.....from purely a performance standpoint, wouldnt it be most effective to have no exhaust on an engine, not even headers? All exhaust could exit freely and quickly
  17. lippy
    Joined: Sep 27, 2006
    Posts: 5,244

    from Ks

    Cut eight holes in the hood and shoot em straight up. Works good for defrosters in the winter too. :D
    jeffd1988, Saxman, Truck64 and 3 others like this.
  18. Dave Rondou
    Joined: May 26, 2008
    Posts: 664

    Dave Rondou

    I would spend what it would take to put a full exhaust system on that Caddy.
  19. Fender1325
    Joined: Aug 31, 2014
    Posts: 730


    Id say in the neighborhood of 5-600 bucks installed. Id probably have an exhaust shop do the work bc itd take a torch to get the old rusty nuts off the manifolds.
  20. Tim
    Joined: Mar 2, 2001
    Posts: 11,870

    from Raytown Mo

    Go get a quote from a shop that normally does hot rod and old car exhaust. I spent $200 on tubing, clamps, bends and hangers and finally gave up and took it to them.

    Custom bent system with the muffler I already had for $150 learned my lesson
    volvobrynk and Fender1325 like this.
  21. LOL and the reason it kills you is not the C part but the O part, a single molecule of Oxygen is called a radical, and unlike the Oxygen (O2) in the mixture that we breath Oxygen in a single molecule is extremely corrosive and will kill you grave yard dead if you breath it.

    It is nearly impossible to get the burble that an old Chris Craft makes, the exhaust empties into the water and that is what causes the burble. I have heard cars with modern chambered mufflers and megaphones come really close at idle.

    If I were going to fix the exhaust I would do like others have said start at the front. A Porter or a Smithy is just a steel pack muffler and you can get them sans the name that sound the same and way cheaper. If you want to run long straight pipes that is fine, it wont hurt you engine. I maybe would consider welding them as opposed to clamping them and I would make damned sure that they exited out from under the body wither sneaker pipes or under the bumper. You can always add the mufflers later.

    Something that I am not sure that anyone has said so I will use myself for an example. I have done things on the cheap because I have had to do things on the cheap. I have discovered that unless I had to have a vehicle to get around that it is way better to wit a day or two and do it right. Done on the cheap is a vicious circle. It gets done and redone, after the first couple of times it could have been done right and not be a bother any more.
    czuch, Fender1325 and Jet96 like this.
  22. That's what SHE said... but splurge and let the shop do the hard work. What takes you 4 hours takes them 10 minutes.
    volvobrynk and Fender1325 like this.
  23. Beaner, some days I start to believe that you have 1/2 a brain when you rattle off shit like that...
  24. The body produces approximately 2.3 pounds of carbon dioxide per day, I think you'll be OK ;) Having a normal level of CO2 in the lungs and arterial blood) is imperative for normal health.

    THANK YOU! I have been preaching this for years, but old wives tails die hard!

    NO! Without any form of manifold or header on the engine, the exhaust coming out of the port loses all velocity and allows Huge amounts of reversion where the spent exhaust gases get sucked right back into the motor during cam overlap and the time that the exhaust valve is still open while the piston is starting to go back down. This will absolutely KILL the power.
  25. Jalopy Joker
    Joined: Sep 3, 2006
    Posts: 25,720

    Jalopy Joker

    more to consider than just back pressure - engine pulses, cylinder scavenging, gas velocity, etc
    Truck64 likes this.
  26. Atwater Mike
    Joined: May 31, 2002
    Posts: 10,347

    Atwater Mike

    An old windbag that lived up the street from us in the '50s got all bent up over my cool Lakes headers (1.62" tubes rolling into a pair of '36 Ford driveshaft funnels)
    "Better get some mufflers on there, open like that yer gonna warp the valves!"

    I said, "Yeah, the biting cold California air'll jet through those hot tubes and freeze-warp 'em like sombreros!"
    I was such a wiseass...
    volvobrynk and Blues4U like this.
  27. Truth of the matter is that Benno is smarter than the average white mouse! HRP
    volvobrynk and czuch like this.
  28. Blues4U
    Joined: Oct 1, 2015
    Posts: 5,093

    from So Cal

    You might recall that at one time the header mfgr's were experimenting with anti-reversion headers. I recall articles in Hot Rod and/or Car Craft that reported good results. Since you're in the bizz I thought you might know more about it. I don't recall seeing anything about it anymore. Maybe it was an idea that fizzled out?
  29. I get bored with real life and read a lot of chit. LOL

    I am like the scarecrow, "If I only had a brain . . ."
    volvobrynk and HOTRODPRIMER like this.
  30. falcongeorge
    Joined: Aug 26, 2010
    Posts: 18,341

    from BC

    This sets up a vision. Benno, racing through a maze, fat-bottom girl at the end of the maze...:D

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