[autoXr1]

Hi folks,
I have a question regarding exhaust headers.

I finally got my beast somewhat dialed in. Basically, it's FTI's Pure Street combo with AFR 165's with all the upgraded goodies, ported Performer RPM, custom cam, Scorpion RR's, lightweight pushrods, Aeromotive fuel system, 30# injectors, etc.

I am using my old FMS ceramic-coated headers, Bassani X-pipe, and MAC Pro-Dumps.

Well, after getting the thing fired up, and letting it warm up for 10 min. or so, I am noticing my headers glowing orange. My Autometer fuel/air ratio meter was reading lean at 36psi of fuel pressure, so I bumped it up to 40. I had to adjust the idle to around 900 RPM to keep it from surging.

Maybe since this is an upgrade from an essentially stock engine, I am not used to seeing glowing headers. However, it seems to me that these headers got a little too hot a little too quickly. The engine was just at idle 99% of the time during this period.

Any input appreciated.

 

[[email protected]]

glowing headers is a result of a lean condition.

 

[autoXr1]

If glowing headers is a result of a lean condition, and fuel requirements are any indication of horsepower, Ed Curtis is THE MAN! I simply asked for roughly 320 HP to the rear wheels...with that in mind, I was thinking of 30# injectors and dialing back the fuel pressure to around 36 or so. It's at 40 and still a little lean...according to my calculations 30# injectors at 40psi will support around 380HP.

I'll have to get this thing tuned on the dyno and may be looking at a custom chip.

 

[MFE]

Could be a massively retarded timing setting too, like your distributor is off a tooth.

 

[Black_Bullit]

If glowing headers is a result of a lean condition, and fuel requirements are any indication of horsepower, Ed Curtis is THE MAN! I simply asked for roughly 320 HP to the rear wheels...with that in mind, I was thinking of 30# injectors and dialing back the fuel pressure to around 36 or so. It's at 40 and still a little lean...according to my calculations 30# injectors at 40psi will support around 380HP.

I'll have to get this thing tuned on the dyno and may be looking at a custom chip.

You're not maxing your injectors at idle, something is wrong with your tune IMO.

 

[autoXr1]

I agree, that I don't have it tuned up yet. Obviously still playing, but I think I'm getting close.

Thanks, I'll double check the timing. Although, when I put in the distributor, the rotor was pointing at my #1 at TDC and my pen marks (I made prior to removal) at the base of the distributor and block matched up. It was previously set at 14*. I could be off a few degrees, but I don't think it could be that far off. We'll see.

I'll see what a few more #'s of fuel pressure do, as well, if that's not it.

 

[autoXr1]

OK, I must have been off a tooth when I installed the distributor. It was at 10* retard. I was able to rotate the distributor to read 10* advanced. Hey, it runs a bit better now. Go figure. I brought my fuel pressure up to 42 psi. My headers aren't glowing and my fuel/air ratio has normalized.

NEW PROBLEM!
Although it runs a lot better at idle, when I had my timing light on it flashed erratically. As if it was misfiring. When I revved the engine, it had this "sweet spot" around 2000 RPM where everything as smooth, but as I went higher, it began to have a noticable stumble. I pulled the plugs....they looked like new. No abnormal appearance that I could tell.

New Autolite plugs, new Taylor 10.5mm race wires, new MSD cap & rotor. Jacobs Ultra Team ignition.

Any ideas? I will have to pull the distributor and find the right tooth. If I was able to rotate the distributor to read 10* advanced, would the distributor position create this ignition stumble?