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bb bb is offline
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Join Date: Jan 2001
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CIS question on my 2.7Turbo

I have just a quick question. I have a 76' 2.7 turbo (BAE). Last winter I installed a set of BB headers with a larger ID that the stock exhaust. Now I know that larger headers takes the low end out of the motor, and it did just that. I am running MSD with timing computer and Pertronix ignitor.

The question that I have is whether this has thrown out the adjustment on my CIS. And, or, can I adjust the CIS to make the car run a little better on the bottom end. I know that when I did this on an old sportster that I had I had to re=jet.

THE ONE GOOD THING SHE SCREAMS ONCE THE RPM'S GET UP THERE!!!

Thanks
Oscar

Old 04-28-2004, 12:48 PM
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Check the CO and the A/F ratio throughout the range and on boost.
May need to richen it up a bit or mod the WUR.
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'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 04-28-2004, 03:58 PM
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I think that I am good on boost. This morning coming to work was the first time that I really got to open it up. getting on the highway I got on it in second through fifth. Man the car is strong. Boost came on at about 3500 and it seemed would never end. You have to remember this is the second time in 2 years that I have been able to drive it. I drove it 2 times last year and it broke down both times, (ignition problems). The new MSD setup works great, Now just tuning the CIS? I didn't know if I could turn the adjusting screw in small increments on my own to see if I can feel the difference. If I can't this way then I'd have to take it to my mechanic.
Old 04-29-2004, 04:16 AM
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please tell me more about your turbo. How does the 2.7 hold up with the turbo?
Old 04-29-2004, 06:22 AM
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How much boost are you running?

On mine I'm only up to 5 psi right now until I finish the supplimental fuel injection.

You can play with hte metering adjustment screw but that may or may not make a difference on the bottom end.
Be careful, you don't want to go lean under boost.

Try turning it in about 1/4 turn (max) and see if that helps. Keep track of how much you change it so you can go back. The right way to do it is with a CO meter but some of us don't have those in the garage.

If the only change you made was the headers it may have gone lean, but it might be something you will just have to get used to.
Lower back pressure means less low end torque most of the time.
Old 04-29-2004, 06:42 AM
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I am running 7 lbs. and I just rebuilt the motor. The motor had 116,000 miles when it needed rebuilt. I had the turbo on it since '77. It does not have an intercooler or any enrichment device under boost. I am running the MSD set up so that I can control how fast the timing comes on with the MSD timing box and I can control How much timing is taken out with the MSD-61BTM box (w/boost retard).
Old 04-29-2004, 07:26 AM
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Sounds great, bb! Do you know how much hp you're putting out?
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Old 04-29-2004, 07:50 AM
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Before the new headers it was supposed to be getting 259/ per the BAE spec's from 77. I would think it would have gone up with the new headers but I don't know.

Oscar

Old 04-29-2004, 08:15 AM
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