I tune with Freelog / Crome. I was going over some of the data and Freelog allows you to see the average/minimum/maximum for any sensor in any of the cells.

I noticed that I have significantly higher MAP readings (about 30 millibars) from 2500 to 3500 RPMs. I have read about tuning intake tube length. Would this be a way to measure best results of adjusting intake tubing without a dyno? It seems to reason that this would work but does anyone know for sure?

 

Buuuuuump.

 

Higher map readings as compared to what?

You also need to take into consideration the TPS% as well. Are you seeing higher pressures in those RPM at 100% throttle?

Sure using the MAP and TPS readings in a specific RPM range you could measure the flow variations of the different intakes. If you have some sort of restriction infront of the throttle body it will show that.

 

Generally you will have lower manifold pressure as airflow increases.

What intake system are you using? What camshafts?

 

I guess I should know by now that faster air is lower pressure air. Thanks for the reminder. I have a K&N filter on the stock intake tube but it isn't in a box. B18 LS with Crower 403 (stage 2) cams. I need to just break down and get the cold air piping. I was just wondering if there was any way to tune intake piping without a dyno.