L27 heads - Rockers on 3/8 bolts - Page 4 - GM Forum - Buick, Cadillac, Chev, Olds, GMC & Pontiac chat


Performance, Brainstorming & Tuning Talk about modifications, or anything else associated with performance enhancements. Have a new idea for performance/reliability? Post it here. No idea is stupid! (please use Detailing and Appearance for cosmetic ideas)

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Old 04-20-2010, 10:59 AM   #31
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Originally Posted by oldsrocket View Post
I didnt "drill out" the 1.8 rocker arms when I put them on my heads, You want them to be machined so you know that the holes are straight and true, otherwise you could have issues with binding or what have you.

I haven't had any issues with mine in over 5,000 miles of use
Right, which is why I had a shop do it all for me.
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Old 04-20-2010, 11:57 AM   #32
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LTFT or BLM depending on what software/scantool you're using is the long-term memory for fuel. It'* compensation for the base fueling algorithm. STFT or INT is the short term memory for fuel and it is direct compensation based on input from the O2 sensor in closed loop. (operating temp and not WOT)

Ideally, the LTFT should be around 128 and be fairly steady. The STFT should hover around 128 but will change more frequently.

If you're running lean, you're STFTs will first try and compensate and the values will be above 128. Next, your LTFTs will raise above 128 so that your STFTs will hover around 128 again. If you're running rich, it'll be the opposite.

You're running the same PCM (I think) and code I'm currently running. (I'm using the 94-95 L27/L67 code) It faster than your average OBD1 pcm and there are a ton of unlocked parameters you can tune. More than anything you would ever really need.
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Old 04-20-2010, 12:34 PM   #33
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Originally Posted by 95naSTA View Post
LTFT or BLM depending on what software/scantool you're using is the long-term memory for fuel. It'* compensation for the base fueling algorithm. STFT or INT is the short term memory for fuel and it is direct compensation based on input from the O2 sensor in closed loop. (operating temp and not WOT)

Ideally, the LTFT should be around 128 and be fairly steady. The STFT should hover around 128 but will change more frequently.

If you're running lean, you're STFTs will first try and compensate and the values will be above 128. Next, your LTFTs will raise above 128 so that your STFTs will hover around 128 again. If you're running rich, it'll be the opposite.

You're running the same PCM (I think) and code I'm currently running. (I'm using the 94-95 L27/L67 code) It faster than your average OBD1 pcm and there are a ton of unlocked parameters you can tune. More than anything you would ever really need.
Now its just a matter of getting a chip burner so that I can tune, and a header to make it easier.
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Old 04-21-2010, 11:25 PM   #34
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sorry didnt see that

as for the reversion you spoke about, is that true for sc engines, I'm sure it would help at light throttle
I thought they only used it in na engines to keep backflow down
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