Get your guys opinion and expertise. Hopefully I can learn something from you guys. I have a polluter v2 cam, AFR 205 heads 1/7/8 headers with catted y pipe. I also have a Fast 102 intake, with the NW 102 throttle body and the 104 fast toys lid. Engine is a LS1.

At idle, (set at 875rpm) with the IAC counts set to 55-60, I am reading 68-70kpa on my MAP. The RPM's are not running high, they are running around 875. When I cruise, I have seen the MAP go down to 40kpa.

Is this normal? Is there a way to get the MAP reading back to 15-25kpa at idle? Thanks

 

Why would you want it that low? My cammed 6.0 would idle around 60-65 kpa and ran beautifully

 

I think that MAP range is "sorta normal" for cammed.
You would only get the low idle you mention by being
super efficient and having zero overlap.

Now, you can push MAP down by making the mixture
cleaner, the spark right and so on, and this is in fact
the best indicator of moving in the right direction
with the tune - high vacuum / low MAP.

 

Thanks jimmyblue. This is what I was thinking but wanting to make sure. I will try to play with the fuel and spark and see if I can decrease the MAP value. Right now, I do have it idleing at Stoich for the fuel.

 

Your going to loose vacuum with that cam especially. I'd expect 65-70 kPa at an idle.




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