B2600i Performance Mod

some dude on the site was making 2600i headers.

Yea,I told him I wanted one,but didnt hear from him again,maybe he is trying to get a few made I dont know though..Would love to have one.

Thanks for all the input.Lets see if I can make sense out of all these great inputs. First,I did try 2 1/4 inch pipe and it really affected the torque so I went back to 2 inch and mine runs all the way back as I have to pass emissions and visual which the current set up did.The head has been worked on.It has been ported and polished as has the intake and is running stock valves on the intake, larger on the exhaust side.I too want a header as the guy posted on here but havent heard from him either.I have silghtly modofied the intake by using mandrel bent polished tubing between the MAF and throttle body,eliminating the accordion hose. I also eliminated that funny u-shaped hose on the air box in favor of a short piece of tubing.I am running NGK plugs,Mazda wires dist cap ,rotor button and 40k Accel ignition.AT this point cam is stock,computer is stock and exhaust manifold is stock.Timing advanced to 5 degrees BTDC.Running premium fuel and when I pulled plugs after 100 mile or so they looked ashy as if the truck was leaned out.Thus came the question that started the post.Any other ideas would be appreciated.If anyone knows for sure if there is a fuel cut on the G6 box I would appreciate it as it will save me time chasing fuel rabbits.Lol.Thanks again.BJ

why are you running premium fuel??? and what was the purpose of the oversized exhaust valves??

premium fuel will actually hurt performance. if you can run regular without detonation it will outperform premium. rule of thumb, lowest octane rating that doesnt cause detonation. on the other hand, you could continue to run premium and just bump the timing a little, im actually running 8° of base timing and premium. might have to drop it back down a little when warm weather comes though.

also, what is your spark gap set at. all your ignition upgrades are useless without a larger than stock spec gap. i would go .05-.10" over stock with the upgrades you have. if the problem gets worse you know the ignition is the problem, it should easily support the extra gap.

a little ashyness on the plugs is ok if you dont drive hard often enough to burn the carbon off. could also be too cold of a plug not burning the carbon off. IF its definately lean carbon tracks then you need to start looking at fuel delivery, but like i said, i doubt seriously thats the issue just because the larger than needed stock injectors and a stock tune that is pretty rich anyways. keep us updated, and i will try to help anyway i can.

I am running the NGKs rec. for the 2600i.I beleive stock gap is .o32 and mine are set at .035-may need to open them a tad more.I have about decided I have a small vac.leak somewhere so tonight I am going to retorque all the bolts on the intake , clamps on the throttle body etc and see if that helps.I went back to 6 degrees BTDC and that did not seem to make any difference so I am going to quit fooling with the timing for now.Thanks for the input.BJ