Moparchat - Home of MOPAR enthusiasts worldwide!



Go Back   Moparchat - Home of MOPAR enthusiasts worldwide! > Technical Forums > Performance Talk

Click here to search for Mopar cars and parts for sale.


Reply
 
Thread Tools Display Modes
  #1  
Old 07-28-2002, 09:34 PM
73_RoadRunner's Avatar
73_RoadRunner 73_RoadRunner is offline
Registered User
 
Join Date: Mar 2002
Location: Monroe, Michigan
Age: 41
Posts: 475
Confused Exhaust and cross over pipe question

i have a 73 b body road runner 4 spd i'm gonna get flowmaster 40 series mufflers i was gonna get 3" and dump it at the axle or run it out with tailpipes but a guy said i dont have enough horse power i will lose torque off the line cause low back pressure so i decided to dump 2.5" exhaust at the axle and have a cross over pipe connecting the two pipes thats what a flowmaster tech said to do for most performance my 440 has 400 and some horse

1 how far from the collectors should i put the cross over pipe i have a manual trans to?

2 is X pipe about the same as a cross over for performance?

3 does this 2.5 setup sound the best for my car?

4 the tech told me to have 12 inches fo straight pipe after the muffler then a 45 degree turndown i dont thing i have enough room for 12' after the muffler
thanks!!!



Flowmaster tech said this some of it dont sound right see what you thing run 2.5 pipes start the cross over closest to the collectors run the mufflers 19 " after the collector then 12" of straight pipe then a 45 degree tundown starting the muffler 19" is to close for my car
Reply With Quote
  #2  
Old 07-28-2002, 10:06 PM
pishta's Avatar
pishta pishta is offline
Senior Member
 
Join Date: Aug 1999
Location: Tustin, CA
Age: 55
Posts: 3,987
Default

ideally you can tune the collector for optimum length. You can extend the collector, uncork 'em and run a few WOT drag runs, then check the collector for a color change (sometime a little paint helps) . That is where you can reduce them to 2.5 and run the X pipe. Run the mufflers anywhere after that and run the pipes to the bumper and then turn them down. This'll keep the pulses from reflecting up and causing a reverb when you drive. There is a formula for an optimum collector volume somewhere out there.
Reply With Quote
  #3  
Old 07-29-2002, 03:16 PM
dirty dan's Avatar
dirty dan dirty dan is offline
Inactive User
 
Join Date: May 2002
Location: Rockingham,nc
Posts: 1,027
Default

I ran 3'' to the mufflers and then drop down to 2 1/2 after that. 18'' has been the standard torqe tube requirments for my engines.
For street aplications I would put the muffler about under the rear seat.
The x pipe does not need to be 3''.
Remember that x pipe is not flow related. It`s job is to equalize pressure from side to side.
Reply With Quote
  #4  
Old 07-29-2002, 05:42 PM
73_RoadRunner's Avatar
73_RoadRunner 73_RoadRunner is offline
Registered User
 
Join Date: Mar 2002
Location: Monroe, Michigan
Age: 41
Posts: 475
Default

Quote:
Originally posted by dirty dan
I ran 3'' to the mufflers and then drop down to 2 1/2 after that. 18'' has been the standard torqe tube requirments for my engines.
For street aplications I would put the muffler about under the rear seat.
The x pipe does not need to be 3''.
Remember that x pipe is not flow related. It`s job is to equalize pressure from side to side.

does it matter where i put the crossover pipe? do you think 2.5 dumped at the axle with 40 seris will b nice?
Reply With Quote
  #5  
Old 07-29-2002, 08:45 PM
dirty dan's Avatar
dirty dan dirty dan is offline
Inactive User
 
Join Date: May 2002
Location: Rockingham,nc
Posts: 1,027
Default

You can dump it at the axel.But consider this,1st it only takes a small gas leak to start a big fire,2nd inside the car will be quiter with tail pipes. This is incase you have a radio. the location for the best x pipe. I really couldn`t say, In terms of optimum perf;
Of course some where before the mufflers .
Other then that I would find a spot that would be up out of the way,for road clearance and such.
Idon`t have an x pipe on my 73 charger or tail pipes.
But I do have the3'' from the headers to the flow masters with a 45 degree bend pointing towards the rear tires.
Works grate and I really like it.
But then my cars never use the radio.
Happy trails
Reply With Quote
  #6  
Old 07-29-2002, 09:45 PM
lipmedex lipmedex is offline
Inactive User
 
Join Date: Jul 2002
Location: eglin afb
Age: 52
Posts: 25
Re: Exhaust and cross over pipe question

chief..... let me start by saying "yes" run the 3" exhaust with the cross over just behind the trans tail shaft. that way you don't haft to drop the exhaust to change the tranny. and running it to the axle and pointing it down is real cool. i'm running a 400 big block chrysler. i also have 2" primary headers that are fender well exit to a 3 1/2" collector to 3" dual exhaust with a cross over behind the tranny finally ending just before the rear end pointing down. i have no problem running 11.32 in the quarter. i too have 450 hp with just a little snort of nos. i also drive this car to work every day. the drivability is great and the sound is commanding to other cars on the road. and everyone looking is always a plus.
Reply With Quote
  #7  
Old 07-29-2002, 10:20 PM
73_RoadRunner's Avatar
73_RoadRunner 73_RoadRunner is offline
Registered User
 
Join Date: Mar 2002
Location: Monroe, Michigan
Age: 41
Posts: 475
Question

my 73 road runner 4spd has a 440 with a dominator accel super coil 750 double pumper holley and its sapose to be built some but i dont know what all is done to it so i'm guessing i have 400 and some horse so what would be the best 3" or 2.5 dumped at the axle with 40 series?
Reply With Quote
  #8  
Old 07-29-2002, 11:17 PM
dirty dan's Avatar
dirty dan dirty dan is offline
Inactive User
 
Join Date: May 2002
Location: Rockingham,nc
Posts: 1,027
Default

2 1/2 would be good.
that peice will be so short that it won`t macke any real differance either way.
Reply With Quote
  #9  
Old 07-31-2002, 04:23 PM
73_RoadRunner's Avatar
73_RoadRunner 73_RoadRunner is offline
Registered User
 
Join Date: Mar 2002
Location: Monroe, Michigan
Age: 41
Posts: 475
Question H pipe and x pipe

so whats better for my 440 pefromance and souns wise? H pipe or X pipe? the x pipe can muffle shops like muffler man make x pipe or h ipe for exhaust or do you have to do it?


which would be best for my 68 440 dominator intake 750 holly dbbl pumper accel coil yellowjacket wires holley ma fuel pump 4 spd 4.10 gear i dont want less torque off the line cause of too big exhaust wich would best match my car for speed performance and nice powerful sound so people will hear me and look


1 3" to muffler then 2.5 tail pipes
2 3" all the way back
3 3" dumped at the axle
4 2.5 dumped at axle
5 2.5 all the way back

thanks a lot guys for helpin me out with all these questions i'm glad to get help cause i'm going to race my friends 77 trans am that talks crap all the time how hes gonna smoke my 440 magnium hes starting to piss me off and i wanna show him whos boss
Reply With Quote
  #10  
Old 08-01-2002, 08:08 AM
dirty dan's Avatar
dirty dan dirty dan is offline
Inactive User
 
Join Date: May 2002
Location: Rockingham,nc
Posts: 1,027
Default Choices

Go with the 1st choice 3" to the muffs 2 1/2 out the back.
H-pipe will do what you want it for.
You don`t need 3' out the back.
That would only make the muffler man curse more any way.
He will have enough trouble snakeing 2 1/2 through there anyways.
Go find that fire bug.
I mean fire _ird.
My spelling seems to be lacking.
Could you tell me if it is a t or a b that goes in the blank?
Reply With Quote
  #11  
Old 08-01-2002, 09:31 AM
AAR4fun's Avatar
AAR4fun AAR4fun is offline
Inactive User
 
Join Date: Oct 2000
Location: Indy
Posts: 120
Default

I recently changed from 2 1/2" to the bumper with an H-pipe to 3" to the bumper with an X-pipe. It didn't make any noticable difference other than the sound and slight whistle coming form the X-pipe. I used TTI tailpipes and hangers, Dynomax Super Turbos and an Dr. Gas X-pipe. My muffler guy did a fabulous job putting it together, but I think he will run and hide next time someone brings him an X-pipe. The pieces supplied by Dr. Gas would not work for my application and he had to fabricate some of the pieces.

3" is not easy to work with I understand. It has a tendency to crush rather than bend.

Also keep in mind bigger is louder. Think about what you are trying to accomplish with the car and what you are willing to tolorate. I love driving my car around town on occasion and really want it to move at mid and upper RPM, but wouldn't want to drive it everyday. Too noisy for my taste.

I am about to change the exhaust on another musclecar car I would consider driving daily. It will get manifolds, 2 1/4 to the bumper and mufflers that allow me to hear the tires on the highway.

Use your best judgement...
Reply With Quote
  #12  
Old 08-01-2002, 12:48 PM
sixpackcuda's Avatar
sixpackcuda sixpackcuda is offline
Inactive User
 
Join Date: Jun 2002
Location: Folsom, PA
Age: 66
Posts: 313
Lightbulb Exhaust

Here is a good article on porting your stock exhaust manifolds:

PORTING

I am going to try this to mine over the winter as I don't like headers.
X pipe is better than the H pipe.

And another article on header sizes:

HEADER
Reply With Quote
  #13  
Old 08-01-2002, 03:47 PM
73_RoadRunner's Avatar
73_RoadRunner 73_RoadRunner is offline
Registered User
 
Join Date: Mar 2002
Location: Monroe, Michigan
Age: 41
Posts: 475
Smile 1 more question

so running 3" to mufflers then 2.5 all the way to the bumpers with 40 seris
is that gonna be better performance then 2.5 dumped at the axle?


i want the car to be loud so everyone hears it like that earthquake feel of power but i dont want it too loud like open hearders where i will get pulled over for sure driving on the road what do you guys think? i like that when a car goes buy and and you can tell its got power cause of that cool sound and shakin yer chest a little but not where i will get pulled over no doubt


thanks!!!
Reply With Quote
  #14  
Old 08-16-2002, 02:30 PM
273dart 273dart is offline
Inactive User
 
Join Date: Mar 2000
Location: Green Cove Springs, Fl, USA
Posts: 116
Default

I have not done a lot of reading on H pipes yet, cause I am not quite ready to drop my engine. So, what are the advantages of the crossover. I have heard, increase power, decrease power, increase torque, decrease torque and cut down on nois.
Reply With Quote
  #15  
Old 08-16-2002, 05:10 PM
gsmopar's Avatar
gsmopar gsmopar is offline
Registered User
 
Join Date: May 2002
Location: Chandler / Arizona
Posts: 800
Default

http://members.aol.com/xforcefast/index.htm#exhaust
Reply With Quote
  #16  
Old 08-17-2002, 03:20 PM
Olle B Olle B is offline
Inactive User
 
Join Date: Oct 2001
Location: Höllviken Sweden
Age: 69
Posts: 382
Default

Sixpackcuda
THANKS for the link to exhaust manifolds,,,They didnt wrote what to gain or lose,,,compared to headers,,,but the fact they wrote as a huge improve to grind your original cast irons is enough for me to try that little trick while saving money for the TTI.
Wonder whats the diff is between:
untouched original
grinded original with extra spacers
good headers
At least it will do this season ,,,I have to take care of my wife and a new Holley,,,,a new RPM ,,,and a grinded original will do fine at least if you trust it,,,and for the money of buing new TTI:s I can have two weeks of vacation with my wife in the Canarieislands!!
Thanks again,,,Best regards Olle B
Reply With Quote
  #17  
Old 08-17-2002, 05:17 PM
273dart 273dart is offline
Inactive User
 
Join Date: Mar 2000
Location: Green Cove Springs, Fl, USA
Posts: 116
Default

Agreed, Thanks for the info/web. I just need to do some research when I get to that point.
Dave Davis
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

Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
EXHAUST NOTE H-Pipe vs X-Pipe Duster_340 Performance Talk 10 04-27-2004 10:40 PM
exhaust pipe bender question benwest Ram Truck Chat 7 12-02-2003 07:23 PM
exhaust and cross over pipe 73_RoadRunner Drag Racing Forum 2 08-12-2002 10:45 PM
Cross Over Pipe FAST EDDIE 69 Vintage MOPAR chat 4 03-09-2002 07:06 PM
Cross over pipe on 318 worth it? CrAlt Performance Talk 3 03-24-2000 05:24 AM




All times are GMT -4. The time now is 01:58 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
. . . . .