I should be getting the invoice tomorrow. I'll relay the cost then.

I just got an e-mail with the attached before and after dyno charts along with all info in 10 rpm increments. I can't seem to transfer them to my photobucket account and then to 6speed. I will try again tomorrow.

 

Is that with the stock ECU settings?

 

Yes, the ECU has not been touched.

 

Chad is correct about Marks skill. Rob has always stood by the quality work of Marks. Have have used their stuff with great results of fit and performance.


Theo

 

What's the difference say between these headers and say some Fabspeed headers?

Also what do you mean by catbypass headers?

 

 

 

 

One visual difference is the merge collector section of the header and flange area.


Theo

 

The merge collector is a big difference. Look at the merge point. They are not cut in ......... they are a true merge. A lot of labor goes into this design, Not knowing the type of material and it's thickness could be another. Not knowing the length of each run could be a third. I do not know what type of weld process the other headers use. Finally, I don't know if the others throw CEL or not.

I guess they would be hard to compare.

 

$3,100.00

 

Thanks. The results look great, although the delta shows 20 rwhp, (379-359). Assuming a 15% transmission loss comes to 23.5 hp gain at the motor. I'm surprised a CEL isn't thrown. The pre and post o2 sensor's are used to determine the health and efficiency of the cats. 993s with aftermarket 100 cell cats often eventually throw a CEL. Do you know what the reason was one of the O2 sensors is placed to read upstream at one of the primaries, instead of at the collector where it could read all three cylinders?

 

Steve,

My calcs are off .......... sorry, I was repeating what I was told before I examined the sheets. Although 16% was being used, your numbers are correct. Thanks for the help. It does not throw a CEL. Remember, I said these are kat bypass headers. You are correct about the two sensors and what they do. If you put one sensor in precisely the correct location reading one cylinder and put the other in a location reading all three cylinders you fool the computer. No CEL. There is a bit of design in these headers.

 

What you are refering to as "no side mufflers" is actually no kats.