In the 4 headers I installed, I had 0 problems with leaks and the stock gaskets. As long as you tighten everything from the bottom up and to the right tq specs the original gaskets will not leak.

I used 120,000 mile original gaskets on my IS300 when i put on the turbo and I had no leaks. So they will work 99% of the time.

 

neone know.. bout the questions i asked..??

 

Why not have a CNC'd flange on the header???, just a tiny bit more shallow than oem spec.. so the oem gaskets will compress & seat properly....

 

All right I just got back from getting my headers installed. First of all I’d like to thank Daniel for hooking me up with a set of headers and TC Performance here in CO for doing the install and letting me hang around and take pics while they work. I got to say that I’m glad that I didn’t do the install myself. The install took about 4 hours with pros working on it. After the install was finished we fired her up and the sound that the headers make are a little raspier then stock. It also made the exhaust a little more loud but not very much. Here are some pics from the install.

Here is a video of the car on the dyno after the headers were installed.
YouTube - Mazzuri header dyno - IS350
YouTube - Mazzuri header dyno - IS350 2

Side by side


exhaust removed

 

engine covers taken off and air box being removed.


Tobi and Taylor working on getting the bolts off the headers

 

Headers removed



Mazzuri headers installed.

 

One thing that gave me concern is how close the oil dip stick is to the header.

 

Before the headers were installed we did a base line dyno. The car made 265.1 whp and 227.8 lb ft. Then we did another dyno right after the headers were installed. Just to let everyone know that the ECU has not yet adjusted to the headers so don’t expect any real gains till the ECU adjusts. The car made 264.2 whp and 228.3 lb tq. So the peak hp went down but if you look at the graph there were small gains through most of the power band. Peak torque went up and as you can see it moved higher on the rev range.
I will be doing another dyno next week or in 500 miles after the ECU has had time to adjust. So say tuned.

Oh and after driving the car for about 50 miles I have not gotten a check engine light, so the sim is working perfectly so far.

The red lines are before and the blue is after.

 

Nice job Toptier (Jon). I like posts that are actually worth reading. Looking forward to your upcoming dyno after the ECU has adjusted.

PS..Thank you for spending the time and money to provide us with this non-biased information.

 

yes!! great post! now go drive around lots.. we gotta see the results after the 500 miles

 

I wish I had reminded you earlier today, but I hope you remembered to weigh the headers AND the OEM manifolds. Please say you did ... :|

 

Thanks for the comments guys. The weather here isn't to good today. It was cloudy and cold this morning and afternoon but now its snowing so that means the car is staying in the garage. Tomorrow is going to nice and in the 60's so I can get some miles on her tomorrow.

I managed to weigh the OEM headers after everything was done and they weighed in at 25 lbs. I however didn't think to weight the Mazzuri's before they went on. So if someone that hasn't installed them yet want to weigh them please do so.

 

I bet your car is running out of fuel on the top end. We may need to monitor the a/f to see what its doing. It may need time for the short/long term fuel trims to adjust so drive the vehicle for a few days and then drive it aggressively for a few hours before you hit the dyno again.

BTW, are you running this on the OEM pipe and catback. If so get rid of those rear cats too and then try another dyno run.

 

Headers look nice.. i'd like to see it dynoed on a mustang or dynojet dyno though. Ive never liked Dynapack. Id also like to see a layered, stretched dyno graph to give a better idea of the gains. Right now, the gains dont look that much, but like others have said, once the ECU adjusts, im sure it'll gain more. Tuning wouldnt hurt either

 

I have JoeZ pipe and the OEM exhaust.