articfriends

iTrader: (1)

All summer i have been watching the excellent thread on Tom Robinsons R-tech innercooler and wondering if it would give my boat noticeable results. I decided to test my supercharger,discharge tubing,innercooler and intake manifold pressures and see how much drop i really have from begginning to end and see where my restrictions and shortcomings might be. The following info is what i observed as installed in my boat,for those of you that haven't seen any of my post this is what i'm running:I have a 540 bbc w/m-3sc procharger,it discharges thru( 2) 45 deg bends,goes thru a straight pipe approx 30 inches long,turns 180 degrees into innercooler,comes straight out of innercooler into stock 502mpi intake.I tried to make the pressure test as scientific and accurate as possible. First i obtained 2 calibrated bourdon tube vaccuum/pressure gauges. Then i mounted them to a board to keep them from getting knocked around during the test. Next i temporarily installed a tee between them and pressurized them with a hand pump used for teting pneumatics in the heating industry to make sure they read equally. Then i pulled innercooler out of boat,cleaned the internal core to make sure it didn't have anything on it that would also cause a restriction.Next i drilled and tapped 2- 1/8 in npt holes on opposit sides of innercooler and 1 in the discharge piping after first 45 coming off from. blower.

articfriends

iTrader: (1)

The first pic if you look carefully you can see the test hoses installed on outlet of innercooler and 1st pipe of blower discharge. The second pic is just to give you a idea of what the general layout looks like. The third pic shows the gauge/tubing and how i initially tested innercooler.At the same time i also installed a 3.70" blower pulley so the boost pressure would be as high as possible and show the biggest drop.The intial test i took boat out w/30 pitch labbed prop,pressure hoses mounted on each side of innercooler core plus my helm gauge that reads manifold pressure. Boat ran 84.5 mph @ 5700 rpm's,i had 12.5 psi at inlet of innercooler,11.25-11.5psi at discharge of innercooler and 10 psi inside intake manifold. That tells you there is about a1- 1 1/4 lb drop acrossed innercooler core,and 1.5 psi drop acrossed the stock throttle blades and procharger manifold adapter. I communicated my results to Tom R and he encouraged me to conduct test using the discharge close to blower,not inlet to innercooler and that overall pressure wasn't critical for test. (it's hard to look at gauges real carefully at almost 85 mph in 27 ft boat,wife took the pics).

articfriends

iTrader: (1)

Next,i conducted the test using discharge pressure reading after first 45 on blower and outlet pressure of innercooler plus manifold reading on helm gauge. At same time i also tried a 32 pitch prop which lowered overall boost pressure(i originally intended on conducting all test w/32 pitch non labbed prop w/3.70 pulley because motor doesn't have big enough injectors to support much more than 8-9 psi boost but prop just arrived fri before second test). The boat went 84.2mph @5200,8psi manifold boost. At the lower boost levels the pressure drop was suprizingly close,especially considering the fact that discharge was read before restrictive 180 degree bend going into innercooler.What i saw was 11psi discharge close to blower,9.5psi at innercooler outlet and 8 psi at intake manifold.Adding the 180degree bend and 1 -45 only dropped boost 1/4 pound more than reading it at inlet to innercooler.1 1/2 psi drop from blower discharge to innercooler outlet is not a tremendous drop. The Biggest gain i think i'd see from going to r-tech supercooler would be the temp drop(i haven't figured out how to get a accurate discharge temp from blower) due to the fact it makes 2 passes thru innercooler and second is i could see 1-1 1/2 psi more boost at intake if i got rid of restrictive stock throttle body and went into a enclosure around a bigger throttle body,Smitty
I did this test for my self and all the guys out there running aw504 innercoolers.

cobra marty

I see a couple of things with this data.
1. The linear nature of the boost curve with the centrifugal SC with 8psi manifold at 5200rpm and 10psi manifold at 5700rpm.
2. Both prop have the same slip about 20% and the same mph 84.2-.5
3. The motor is putting out the same torque at 5200/8psi as 5700/10psi as evident by the same mph.

In your next test session could you see what the SC d/c and manifold boost and mph is at different rpm's, i.e. 3000,3500,4000,etc. not just WOT with each prop.

I really wish you had a stellings ext box on your boat!
marty.

Turbojack

do you know what your air temps are after the intercooler?

articfriends

iTrader: (1)

Marty,at any throttle setting other than wide open boost was equal acrossed innercooler and boost before throttle blades was MUCH higher than manifold boost. I'm sure the equal boost was because supercharger was putting out more than motor could use so it was backing up. For example,boat ran 60 mph at 3800 rpm's w/32 pitch,boost inside manifold was 0-1 psi,boost at outlet of supercharger and innercooler was about 8 psi and was equal. If you stood on throttle you would see the innercooler outlet press drop about 1 psi from blower output press until you backed off throttle to another steady throttle setting.W/the 30 pitch prop i had 6 psi of boost at 2500 rpm's at i/c outlet cruising at minimum planing speed and i saw as high as 15 psi at innercooler outlet cruising at 60 mph 4200 rpm showing 0 vacuum or boost in intake,that must be why boat literaly go's insane when you stand on it at that speed. I meant to conduct these test w/ a 32 pitch LAB FINISHED prop w/the 3.70 blower pulley but there was a problem at houston prop,i ordered a 32 lab 3 wks ago from darin but he says they shipped him a 30 pitch instead so he re-ordered it and it got shipped directly from bam to me but showed up a standard 32,i will have to have him lab it later. I was sorta hoping to see about 87 mph around 5400/5500 w/32 pitch lab w/boost coming in earlier with smaller pulley but i'll probably have to wait until next season now,Smitty

articfriends

iTrader: (1)

Turbojack,i don't have access to a merc scan tool and couldn't think of a easy accurate way to measure the air temps but i may in my quest for knowledge,Smitty

tomcat

Nice work Smitty!

"Adding the 180degree bend and 1 -45 only dropped boost 1/4 pound more than reading it at inlet to innercooler"

I am not sure what you mean by this. Did you measure blower discharge pressure and intercooler inlet pressure at the same time?

Looking at your numbers I would say the following:

Blower discharge pressure before the first elbow would have been a bit higher, say 11.5 psi for argument's sake. This would be a 3.5 psi total pressure loss from blower to intake. This is not bad, but can always be better. With the supercooler design we have measured a 2 psi loss from blower to intake manifold at the about the same HP (flow rate). Compared to an original installation with 3 @ 90 degree elbows and a total pressure loss of 5 psi, that was a big improvement. Since your existing pressure loss is not as bad, there is less room for improvement.

I don't know if you measured blower discharge pressure and intercooler inlet pressure at the same time, but based on the ratio in the first test, I would estimate you had 10.5 psi at the intercooler inlet to go along with the 9.5 at the intercooler outlet. Combined with my estimate of discharge pressure at 11.5 psi, you only lost 1 psi from the blower to the intercooler, including the 180 degree turn. Still, that turn and the transition into the throttle body are the best places to look for less resistance and more power.

The way to judge what power you might gain is to look at your pressure drop now and see what it would be if you cleaned up the air path. Let's say instead of getting 8 psi out of 11.5, you could get 9 psi out of 11.0, as we did with the supercooler design. The new HP would be (9/8)squared or +6%. Add a little for better cooling and you might see +7%, no more. So on an 800 HP engine you're talking about and additional 50-60 HP. The point is you did it without spinning the blower any faster, and 9 psi this way is better that 9 psi with a smaller pulley.

If you were a person trying to decide which supercharger system to buy, the advantages of our intercooler make it the best choice (IMHO). But since you already have a system that is not bad (only 2 @ 90 degree elbows), I would suggest trying to improve it on your own.

Procharger carb guys can switch to a supercooler and it's worth it, because we have seen gains of 85-100 HP. But that's because their stock intercooler setup is much worse than yours. Procharger EFI guys with the 324 intercooler would also find the switch to our supercooler worth it because of the smaller core and piping used in the stock setup. Procharger guys that have the larger 504 intercooler like you, but were forced to mount it on the floor and have 5-6 @ 90 degree elbows could benefit because there is so much pressure loss through those elbows.

The way we dealt with the 180 turn was to slow the air down first in the transition from the blower to the intercooler. The throttle body then draws off the lower intercooler plenum so the losses aren't as bad as a transition from hose to throttle body.

Turbojack

Tom, How much of the pressure drop is related to the air being cooled down? You say your supercooler design only has a drop of 2lbs. If you did not have water going to the intercooler what would the drop be?

tomcat

Turbojack:

When I say that the supercooler only loses 2 psi, I'm talking about resistance to air flow only, not the pressure drop that comes from cooling the air. These are two different processes, although it is confusing since they are both measured in psi. Look at these results and you'll see what I mean.

This is a comparison of a Procharger intercooler and carb box to a supercooler carb box. You can see that the supercooler always has ~85 HP advantage whether the water is running or not. It flows better because it only has 2 psi resistance vs. 5 psi for the Procharger in this case.

You can also see that turning on the water in either intercooler only adds ~25 HP. This gain is due to the increased density and therefore lower pressure after the intercooler, but it is a small gain compared to improving air flow. The main reason you add water is to greater lower temperatures for safety against detonation.

The last column is just the change in boost pressure and has nothing to do with the 2 psi pressure loss that we are talking about.

Clear as mud, right?