Found a setup locally out of a '79, has headders, etc. everything from front to back. Will this fit in my '80?

Thanks, Dan

 

Provided the 79 has the correct trans crossmember that directs both pipes under the passenger side then yes. If it has the crossmember with the openings on either side of the transmission mount then no unless you swap crossmembers.

 

Hey Dan. I'm the person with the exhaust your looking at. If CaseyJones is correct about the crossmember I would be open to swapping crossmembers with you if they are interchangeable. I put sidepipes on my car so that's not important to me. Hopefully someone will chime in on their interchangeability.

Pat

 

'79 crossmember pictures I am seeing on internet show the 2-hole variety ends at 1979.

That would mean the 1979 pipes, using stock routing through the 2-hole crossmember will not pass under the OEM 1980 crossmember.

An option would be to get an aftermarket 1980 crossmember from Bow-Tie or others to accomodate duals that route under both sides of transmission pad.

 

The earlier crossmember will fit as long as it is the one that bolts in. One set of holes might need some massaging to work correctly at the frame rails but I have heard differing opinions on that. There are other pieces needed to make it work correctly, such as the exhaust pipe mount that fits under the trans mount to keep the pipes centered in the holes.

For 1980 GM started routing the exhaust into the cat ahead of the crossmember. This let them change the crossmember to remove the holes and instead use a solid crossmember with a raised area under the passenger side to allow the pipe to pass under it. To use the earlier type of dual pipes the earlier crossmember (and its sundry parts) is needed.

 

is your car an automatic transmission?

 

Yes. It's an automatic.

 

1980 L48 Auto

I modified my 80 cross member to allow for dual exhausts. I installed a 79 exhaust system. I didn't want to go with the 79 cross member because I didn't want to deal with the tight alignment issue with the through the hole cross member. (image borrowed from Myko)

 

Also had to mod the cross member on the 82 driver side.
3 inch exhaust. [/COLOR]


[IMG][/IMG]

 

Nice mods. If I didn't already have an early crossmember I would consider fixing mine that way.

 

Somebody before me has already notched the cross member, I am going to contact Cool95Vette and go with it!!!
Thanks, Dan

 

Rob, your right side exhaust pipe appears to be very close to your trans fluid pan. Any issues with trans fluid and heat? The reason I ask is I'm thinking of going with larger exhaust on my 80.

 

Why go through all that trouble if you are going to run a x member? Use an x pipe and save yourself the trouble.

I don't care if the x member adds a billion horsepower and removes every nano particle of pollution.

It is not a true dual system. End of discussion.

 

 

Hey Maddan, didn't you see Commander 47's post. That was the end of the discussion

 

i have no idea what you're trying to say here

 

I think he is saying why go to 3" when an x pipe will improve smaller pipes ??? I of course could be wrong..

I have the X pipe and 3" exhaust to put on this spring , I figure if your gonna do an exhaust might as well plan for later date mods I am sure to do ..

 

Being the incorrigible old butthead I am, I expect a bunch of guys to flame me on this.

If you use a cross pipe, or an x, y, z, q pipe to connect the two halves you do not have a true dual system.

Simply put, if you are going to connect the two halves, why go through all the trouble to modify the cross member for true dual if you aren't going to use it?

You can do the same thing by just keeping it stock and replacing the cat with an X pipe.

True duals, properly tuned and set up for you needs, will outperform any connected system. Otherwise, why don't racers connect theirs?

In the example above, and I don't know what kind of motor or headers are on the car, the 3 inch pipes are probably gross overkill for a street car.

Two smaller diameter pipes and no crossover pipe will probably produce better backpressure and more horsepower.

That exhaust system as it is cannot be street legal and probably way too loud and more than likely loses horsepower.

You have to have it checked by an exhaust specialist to know. Magnaflow is probably one of, if not the best. But Hooker isn't bad.

This is true dual. These are long tube headers dumping into 4 inch tubes that are baffled to provide correct back pressure.


This is also a properly tuned and set up true dual system for a street car:



This is NOT a true dual system. You could have one pipe coming off the X and if it is the proper diameter, you don't need the other pipe. But that doesn't look as sexy from the rear

 

No flame, just research:
If you get better performance with an X pipe who cares if it's really a true dual exhaust pipes or not? Funny that you mention Flowmaster, they pretty much destroy your argument that, "True duals, properly tuned and set up for you needs, will outperform any connected system."

"Flowmaster strongly recommends using a crossover tube, otherwise known as an “H” pipe or balance pipe on all true dual exhaust systems. The crossover pipe equalizes the exhaust pulses and allows the sounds waves to communicate between both banks of the engine. Not only does this usually improve torque in the low to mid rpm range, it also creates a deeper mellower tone both inside and outside of the vehicle and helps eliminate “back-rap” on deceleration."

"Flowmaster has performed extensive testing and determined that the “H” and “X” pipes deliver no significant difference in performance, but do affect tone, the “X” pipe giving off a higher pitched tone. Flowmaster Scavenger “X” pipes however do increase torque through use of their patented
D-Port technology and retains the deep Flowmaster muffler tone desired by most performance enthusiasts."

Source: http://www.flowmastermufflers.com/?page_id=12583

 

Two smaller diameter pipes and no crossover pipe will probably produce better backpressure and more horsepower.

Back pressure DOES not make hp .. If it did we all would stuffing steel wool into our exhaust pipes not adding headers and free flowing mufflers LMAO