Thought on Headers

[brazilfree]

I am thinking hard about going with headers to get the full measure of the 475 LPE/500 Cam pkg. I am not sure I am ready for the increase in sound ( I have a 700hp street Fox Mustang that is a bit on the loud side). I know I am loosing a lot of HP due to my 4L80-E transplant an I think the headers would help there.

I am interested in the sages thoughts on the sound / hp etc as I do like driving my ZR1. It will find the track every now and then too. Thanks in advance.

[Z Factor]

Headers will make an improvement just as you suspect, however the noise factor will be based more on what you put on afterwards. If you put cats and a resonator on then it will probably sound pretty tame. However most people that put on headers don't want a restrictive exhaust system behind them unless their state requires it.

It will also depend on what catback system you choose that will determine the note and level of sound you will get. You can look at this thread for ideas along those lines.

http://zr1netregistry.com/forum/showthread.php?t=470

Personally, if I were putting on headers to a modded engine I'd want the same set up I have with no cats, an x-pipe and a B&B, the noise/resonance be dammed. That is unless it was going to be a daily driver, then you might not be able to deal with it.

The bottom line is that Headers are one of the better mods for our ZR-1's.

:cheers:

[brazilfree]

Headers will make an improvement just as you suspect, however the noise factor will be based more on what you put on afterwards. If you put cats and a resonator on then it will probably sound pretty tame. However most people that put on headers don't want a restrictive exhaust system behind them unless their state requires it.

It will also depend on what catback system you choose that will determine the note and level of sound you will get. You can look at this thread for ideas along those lines.

http://zr1netregistry.com/forum/showthread.php?t=470

Personally, if I were putting on headers to a modded engine I'd want the same set up I have with no cats, an x-pipe and a B&B, the noise/resonance be dammed. That is unless it was going to be a daily driver, then you might not be able to deal with it.

The bottom line is that Headers are one of the better mods for our ZR-1's.

:cheers:


I have Borla on it now. I know the 4L80 is larger than a normal Corvette auto so some fab work may be required (just not sure). Thanks for the feedback. I also have reviewed the link a few time over the last month. I think I will go with the headers and see what I have to do for another exhaust. It has a date this month with Mark to refinish the engine, I will let him direct from there. Thanks again.

[jonszr1]

good call on mark ya cant go wrong with him. a plus guy that truely cars about this special car.

[brazilfree]

good call on mark ya cant go wrong with him. a plus guy that truely cars about this special car.

Thanks I have the car in on the 18th.

[lbszr]

SW headers and B@B with resonator and today I don't think I even noticed the rumble:thumbsup: . Could be loud for a everyday driver though.

[mrzzzr1]

I added Flowmaster exhaust to my original factory headers with cats which I think had a very nice deep and powerful sound and definitely louder than the original exhaust note. The Flowmasters definitely added power but I never dyno'd to find out how much,

Then > I replaced the factory tube headers (with cats) with long tube headers (minus cats). My headers were made by PFE (Performance Fabrication Engineering) in Harrison Twp, Mi who claim to have made the headers for the ZR1 world record run back in 1989 which is what they installed on my car. PFE's headers had the connections for the air pump which I still have connected and operating.
The sound of these headers combined with the Flowmaster exhaust is very loud except at idle including resonace on the highway. Sometimes I don't even bother turning the radio on because it's hard to hear anyway unless I crank up the volume. PFE says its one of their favorite sounding systems; their headers on my car with the flowmaster exhausts.

I have one additonal thing to mention > I get a some backfire sounds when I downshift. My mechanic says the backfire is due to the air pump being hooked up and a lot of raw gas going into the exhaust when I am downshifting. He says he can disable the air pump but is concerned about setting a trouble code in the engine computer.

With my exhaust system long trips are definitely not recommended due to the volume of the overall exhaust sound. Being a guy who grew up in the original musle car era of the '60's I live with the sound and enjoy the benefits of the power. Plus no one ever doubts there is power under the hood.

If anyone has feeback on the backfiring it would be appreciated.

[jonszr1]

my flowmaster ex with headers and no cats is pretty quiet except for when i put my foot in it. does your system have a resonator. Mark haibeck can redo your prom to stop that i believe he charges 100 for it

[mrzzzr1]

How do I contact Mark?

[brazilfree]

How do I contact Mark?

He is listed in the shops on this site:

The ZR-1 Specialist
430 D Kay Street
Addison IL
630-458-8427
http://www.zr1specialist.com

[XfireZ51]

How do I contact Mark?

mr zr,

Any pics of the headers from PFE? Do they have a website and what was the cost if I could ask? As for the exhaust popping, you may want to check for air leaks. Also, invoking DFCO and DE routines in ECM will cut down amount of gas on decel. What year is your Z?

[Jeffvette]

I have one additonal thing to mention > I get a some backfire sounds when I downshift. My mechanic says the backfire is due to the air pump being hooked up and a lot of raw gas going into the exhaust when I am downshifting. He says he can disable the air pump but is concerned about setting a trouble code in the engine computer.


You need a better mechanic or one who is more in tune with LT5's. The air pump only works upon vehicle start up. it ingests air into the manifolds to help get the cats up to temp. You can unplug the air pump with no drawbacks. The back fire is caused by excess fuel not being burned off in the combustion process.

[XfireZ51]

...The back fire is caused by excess fuel not being burned off in the combustion process.

Yes but there's air entering the system to light the unburned fuel.


mrzr,

Where do you hear the popping? From the rear or under the car?

[Jeffvette]

Yes but there's air entering the system to light the unburned fuel.


mrzr,

Where do you hear the popping? From the rear or under the car?

And it's not coming from the air pump. Haibeck has figured out where to fix this in prom tuning.

[mrzzzr1]

No pics of the headers and I bought them 5-6 years ago and bought the last set they had laying in storage. They looked just like the stock headers minus the cats.

Price then including install was $900.

PFE stand for Performance Fabrication Engineering and they fab custom exhausts and also install aftermarket exhausts.

What is the recommed way to disconnect the air pump if I should opt to do it?

[mrzzzr1]

I plan to contact Mark Haibeck re doing the fix to my prom. Thanks for the suggestion.

As for where is the backfire occurring it is inside the exhaust sys. I tend to downshift a lot when braking so my driving style may be a contibuting factor.
I have spotted flames coming out of the exhaust tips in an autocross when my son drove the car. The last leg before stopping was a short accelleration followed by a pylon garage with a sudden stop. So, when he did a quick accel followed by immediate brake the excess fuel ignited and shot flames out of both sides exh tips.
I want to elimiate this though and it probably isn't good for the exh sys either.

[jonszr1]

call mark he can do it .you will have to send him your prom

[tpepmeie]

This backfiring is caused by the DFCO (decell fuel cutoff) settings in the stock calibration. The settings call for extreme timing retard when the DFCO is active. The retarded timing, combined with any residual fuel in the cylinders cause the popping.

SImple fix is to disable the DFCO. Second fix is to lessen the spark retard setting.

todd

[XfireZ51]

I plan to contact Mark Haibeck re doing the fix to my prom. Thanks for the suggestion.

As for where is the backfire occurring it is inside the exhaust sys. I tend to downshift a lot when braking so my driving style may be a contibuting factor.
I have spotted flames coming out of the exhaust tips in an autocross when my son drove the car. The last leg before stopping was a short accelleration followed by a pylon garage with a sudden stop. So, when he did a quick accel followed by immediate brake the excess fuel ignited and shot flames out of both sides exh tips.
I want to elimiate this though and it probably isn't good for the exh sys either.

Jeffvette,

Agreed its not coming from airpump.

mrzzr1,

I wrestled with this issue for sometime on my 84. Played with the cal removing fuel with DFCO and DE routines, bumping lower MAP timing etc. Turns out I had a rear muffler/pipe interface that was leaking. Thought it was tight. Needed new clamp. No more popping. :thumbsup:

[Nick]

And it's not coming from the air pump. Haibeck has figured out where to fix this in prom tuning.

He fixed it on my chip, and it works great. :thumbsup:

[mrzzzr1]

Yes but there's air entering the system to light the unburned fuel.


mrzr,

Where do you hear the popping? From the rear or under the car?

I just replaced the PCV block connector at the Right Rear (driver side) of the moror. It was in bad shape and quite loose. I now beleive air was entering there and contributing to backfiring. Exhausts seem to now have quited down a bunch with the new PCV block connector in place.
My backfires seem to have stopped now. I am not sure this part really fixes this problem for sure. I just drove the car once so far so I don't know for sure yet. Does anyone know if a leaky PCV block connector could contribute to backfiring?
Thanks,
mrzzzr1