Pressure drop through intake manifold?
Pressure drop through intake manifold? This is actually on a truck but maybr someone in here can shine some light on this... Hanyone ever tested this? Got 5.3 procharger truck im working, had it on the dyno so I did some testing. Had a boost gauge at the head unit, after the intercooler, and inside the intake manifold.
At peak rpm it had
23psi at head unit
19psi after intercooler
14psi inside the intake manifold
Now the drop in the intercooler doesn't surprise me, but what did is that we lost close to 5psi of boost going through 2 feet of pipe, the tb, and into the intake manifold. This was confirmed with 2 gauges and the map sensor. It seems to have this drop across the board, from start to finish it just has that much drop. Has anyone ever tested this before? Just want to see if this is normal or if we have a problem. The cold side has all been pressure tested but the intake manifold itself has not. It's a stock 04 truck intake btw
At peak rpm it had
23psi at head unit
19psi after intercooler
14psi inside the intake manifold
Now the drop in the intercooler doesn't surprise me, but what did is that we lost close to 5psi of boost going through 2 feet of pipe, the tb, and into the intake manifold. This was confirmed with 2 gauges and the map sensor. It seems to have this drop across the board, from start to finish it just has that much drop. Has anyone ever tested this before? Just want to see if this is normal or if we have a problem. The cold side has all been pressure tested but the intake manifold itself has not. It's a stock 04 truck intake btw
IMO the intake will show a little drop in pressure if the volume of the intake is more than the intake pipe. So the air being pushed in gets into a larger space which will show a lower pressure. Not sure how much to expect though. And some may argue the point. This is just my .02
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FWIW I use a itty bitty portable compressor with a harbor freight regulator and a gauge for acetylene from a welding shop with a fitting and valve so I can screw gauges in to the output side. On the output side I have a air block with 4 ports.. and plugs.. (Acetylene gauges max out at about 25 lbs and they get broken a lot in service so they are readily available..)
I set the regulator to 10 lbs(Reading on the gauge), then I just test the sensors or gauges with that setting, just so I know they are all referenced the same, Probably better ways somewhere but at least then I know
I set the regulator to 10 lbs(Reading on the gauge), then I just test the sensors or gauges with that setting, just so I know they are all referenced the same, Probably better ways somewhere but at least then I know
I had 2 mechanical that I both tested at the same spot and they where right on, I used the one the dyno had, and also read what the map sensor was reading, I even moved them around to try that but all confirmed this, I was convinced one was off but it just wasn't. The map sensor is on the rear of the intake on top, the port I used was mid intake on the top aswell, It has the little deals there to tap in for vacuum supply
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Its electronic tb cause it's an 04, 4in threadstone intercooler with 3 in piping, it go's up to 4in shortly after the cooler but the tb is only 78mm anyway. Intercooler is right in front of the rad, it just come's around the rad and back up to the tb, just like we had always done are turbo stuff.
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3inch outlet to 4 inch transition then back down to 3 inch at tb doesnt help...but you also factor in overlap of the cam as well as remembering how the inside of the truck intake is designed.
Its a stock bottem 5.3 with .020 milled 243 heads, 224/233 lift around 600 don't remember exactly but lsa is 114 and advanced 2 degree's. Has big headers and dual 3 inch exhaust. I feel the combo is right, I just hate that im eating up so much boost. Going to switch to a race style intercooler that won't loose any more then 1psi (hopefully), and considering an open plenum intake manifold like a holley high ram, match it with a big tb and run 4in the entire way. See if I can get a cooler with a 4in outlet. Its just alot of money to spend 
. Iv made over 1k with a setup like this on a turbo engine.
. Iv made over 1k with a setup like this on a turbo engine. You want to keep boost...dont run long lengths of 4inch pipe. Esp after intercooler. Keep the pipe with as few transitions as you can then transition at the tb from 3 to 4 with an adapter coupler if you are going to use a 4inch tb. otherwise take that 4 inch pipe out, replace with 3 inch and you should see less drop.
Stock truck intake is a dual plenum design. Air enters through the TB (true 78mm opening) goes like 10" and is then forced upward through a opening into the larger 2nd plenum that feeds the runners. I bet thats your problem.
Theres a company that cuts the top off and hogs the hell out of the intake and then puts it back together. Suppose to make a very noticable improvement. Or you can step it up to a different OE intake, new TBSS style or a Dorman truck replacement. I have the dorman but was questioning its quality with boost but the inside plenum looks like the FAST bc dorman owns rights to the FAST base mold. I already ported my dorman, going to permanently epoxy the halves together and boost it next season.
Theres a company that cuts the top off and hogs the hell out of the intake and then puts it back together. Suppose to make a very noticable improvement. Or you can step it up to a different OE intake, new TBSS style or a Dorman truck replacement. I have the dorman but was questioning its quality with boost but the inside plenum looks like the FAST bc dorman owns rights to the FAST base mold. I already ported my dorman, going to permanently epoxy the halves together and boost it next season.
Looking at how these truck intakes are designed is what really had me questioning if it could be it, that's why I was looking to see if anyone had ever tested it before, no luck here or over on pt. Ill look into some intakes and see if I can find a good open plenum intake
IDk what the new truck intakes look like bur your stuck with the new stock style (if its an open plenum design), Dorman and the FAST truck, Holleys. Otherwise you need to go shorter car style and then your possibilities open up.