After a disappointing dyno run last week where we compared a stock car (VandyZ) to my car with the custom long tube equal length (as best we could) headers we did not make the HP we wanted. There was power there, we just knew it. VandyZ ran six runs with increasing HP on each run and mine just stayed a constant 5 or so HP higher with no fluctuation most likely because mine sat in the cold while we ran his. We only ran mine 3 times as well.

It was decided that we run the car on the same dyno at Balanced Performance in Atlanta that I ran immediately before embarking on this long tube journey. Not to our surprise the results were better than the first test. It probably helped that we added extra miles to the modded car to let every thing break in. As you can see TQ starts to increase just after 3k RPM till 4100 RPM then follows stock curve again until about 5500 RPM all the way to redline. The HP difference follows the same power trend as the TQ. The numbers are on the sheet. If you have any specific questions on the plot or the dyno runs please ask them.

The headers gain a maximum of 15.1 HP and 12.4 ft-lbs TQ at 6400 RPM (where the Z needs it the most). In the RPM range of 3-4 K it is a gain of about 9 HP and 8 ft-lbs TQ. This is the greatest proven gain of any bolt on modification yet.

If you think you would be interested in purchasing these pending price please email me at crawfordzcar@comcast.net. You can also post to the thread but if you want a true response please email. There are too many forums where this info will be posted for us to respond.

High flow cats soon to follow!!!!!! And we are also working on the other end of the engine. No its not a CAI!!!

Ready to see to dyno charts?

Custom long tube headers yield HP/TQ

 

Cool You have mail

 

We have already received several emails with questions. I will be helping Doug with responding to the questions and requests via email and posts on the boards. Give me about an hour and I will post up some more info.

Thanks,

Adam

 

Were y'all running w/o cats?

Thanks,
Jeff

 

They had cats... these were a exhaust manifold replacement.

 

Sound: It is louder. It is more throaty and sounds very aggressive at WOT going through the RPM range. The sound alone is worth the money for you "I got an exhaust for the sound" people. You can sorta hear the difference on the dyno video at Middle Tennessee Z Club between mine and Doug's car. I will try to get a sound clip tomorrow on the way to the drag strip.

Install: It requires that the steering rack be lowered, radiator drained for removal of two water lines, remove intake, remove starter, remove stock headers, replace stock studs with shorter ones, put new headers on and replace all removed parts. (best I remember as this was 2 weeks ago) Estimated 4-5 hours with a lift.

Price: Well it depends. Quantity, material, coating, and time for the finishing welds. Doug wants these to be priced competitively. From everyone’s prior comments the $1000 number seems to be what people want the price to be. Doug will try his best to comply but he has costs too. He has tons of free hours already in this endeavor. I will say if he can get them done and price them for $800, he will. Please understand they could come out costing $1100 or more. We just don’t know today. So lets just see what he can do.

Looks and fit: Well we cant show you because we don’t want to compromise the design. They look nice. Bends and wraps are the key to long tube equal length headers that fit to the stock exhaust with stock cats. YES STOCK CATS CAN STAY!

 

Thanks, that's what I was hoping! Any problems at all with the "check engine" light?

--
Jeff

 

The ck eng light has never come on and we have more then 600 miles on the headers. The headers do fit in the car with the stock cats so everything is still stock as far as the ECU is concerned.

 

The check engine light didnt come on when you dynoed it? I was the other Z owner there when it happened and I remember you and your buddy where trying to figure out what caused it. They had it hooked up to the computer to find what the code was. Just wandering what it was and how you fixed it. These headers sound like they might be worth it.

 

The check engine light was not due to the headers, but due to the TPS potentiometer on the throttle from where he bent it for better heel-toe. We set it off tonight during the video shoot again! He is going to let the dealer fix it under warranty.

 

Whats up Vandy! I was just wondering so that we knew if it was the headers or not.

 

Yeah, the first time it happened we brought it back to the shop and said "Doug, we broke your car" then it happened on the dyno a couple times and once more tonight. The code is cleared and we were good to go again.

Video and sound clips to come later tonight . . .I hope. The editor (Chris) I guess thinks he will be nominated for a OSCAR or something because it is taking forever.

 

The ck eng light has come on in this car a bunch of times due to the fact that the throttle potensionmeter goes off scale when someone with a supper lead foot stabbes the throttle. It happend way before we installed the headers and needs to be fixed by the dealer. I have no problem with it but other people do.
Just haven't had time to take it back. The reason why we know this is we have pulled the code several times and it is the same code every time.

 

Do you have an update on the headers? I'm interested. I live in Atlanta, maybe if we can deal, I could come out there and have your guy install them? I don't know of anybody here who could do it.

Thanks!

Mike

 

Video Here:

https://my350z.com/forum/showthread....threadid=21852

 

We are curently testing cats with the headers and will start the 2nd prototype set of headers this week. Hope to have some of the headers made by the end of the month. As for install Balance Preformance in North East GA should be able to install them for you, if not there we would be glade to do it.

 

I'm down for a group purchase on these.

Are they jet hot coated, nickel, or what?

Have you noticed any problems with heat like with a grounding kit or CAI etc?

Have you considered mid lenghts or would they pass a visual?

 

Yes, a group buy..That's the ticket...

Mike

 

Iam thinking jet hot with steel tubing after to talking to several people this is the way to go the coating really keeps the heat in the headers

I don't have any of that stuff on my car but I wouldn't think so



Short tubes won't make the power, will they pass a visual I don't know but I can tell you this You can't hardly see them

 

That all sounds good to me,

thanks for the quick response.

Our cats are very oddly shaped and hard to mate up with. Not your "typical" cats shape wise, I had already looked into replacing them but there isn't a replacement match out there.

I see you are from TN so I just want to clarify something
(we speak slightly different here in Cali )



Do you mean you *can* hardly see them?
As in they are not easily seen?

Or you "can't" hardly see them?

Same meaning but with a slight Southern draw?

In this context, " Them thar headers shoot you can't hardly even see them? "

Or are they obvious when looking down at the engine bay?

I am not poking fun I have afriend from TN and he talks real slow with a draw and it's hard to understand him but he is a real cool laid back guy.

I will be following this thread closely with interest, it's on my to do list especially if they are not real obvuos visual wise. I am not worried about sound my car is already real loud, I just want a freer exhaust gas flow. They are 2.5 in right? With bolts and gaskets included? What size collector?

Please look at my current Y-Pipe and tell me if these (yours) will match up.

link click here

What you can't see in this pick is the cats actually turn upward towards the manifold to forma stupid semi U shape!