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cast iron vs steel headers
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TOPIC: cast iron vs steel headers

Re: cast iron vs steel headers 11 years, 1 month ago #15447

Here is a dyno of my current HC motor, and my last LC motor (now installed in Dan Pina's car). Had I only only known dyno tuning was so effective, I would not have built the HC piston motor! Both cars ended up a bit over the cap, and will be detuned. A muffler did it for my car. In any case , you can see what healthy motors' HP & TQ curves look like:

Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re: cast iron vs steel headers 11 years, 1 month ago #15448

  • joeblow
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Doc,

Can we see the A/F ratios on those charts as well?
Old Racer!

Re: cast iron vs steel headers 11 years, 1 month ago #15449

The A/F ratios are at the bottom. HOWEVER, our short exhausts, with a highly angled cut outlet, seemed to be causing the A/F ratios to read about a point high vs. the A/F ratios from the sender installed installed just after the collector, which should be more accurate (less contamination from ambient air).
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re: cast iron vs steel headers 11 years, 1 month ago #15450

  • joeblow
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Yep sorry I am more used to wildly varying A/F ratios, I figured they were cut off until closer examination. So you are saying that your wide band O2 is showing 1 full point richer on average? What is your peak A/F ratio at redline?
Old Racer!

Re: cast iron vs steel headers 11 years, 1 month ago #15451

Yes, I was showing AF's in the high 12's.
Eric Kuhns

National Director Emeritus

2007, & 2008 National Champion
2011, 2012 2nd

Re: cast iron vs steel headers 11 years, 1 month ago #15452

Racing in Phoenix this weekend, yesterday was up into the 90's, today is a little cooler and we race at 12:30, will give more input later, gotta get to the track now. I will say my water and oil temps are pretty high, I wonder if the more restricted cast iron can contribute to that??? My last motor with 5 less h/p and 7 less pounds of torque with most of the motor being cryogenically treated never got hot, regardless of ambient temps.

Steve's dyno compared to mine proved to be accurate, for the start, we were on the front row and were dead nuts even, Firebird main is a drag strip so we side by side from a first gear start to to the top of 4th gear.

Since getting these cars to 138/138 is so doable, we are going to have some great racing!
Norman #99
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