Bone's Engine Pull - Part Deux

Roe Blower Vacuum Problem

The stock MAP sensor was used and the reading was taken during a dyno run. SnakeDoc a/k/a David Weaver at American Racing Technology did the build and the tune. Now that he has posted in this thread, I hope he will participate in this discussion. He knows more about my truck than I do. :eek:
 
Muzzy said:
That graph doesn't seem quite right. The problem I see is that you are getting the data from the MAP sensor. I would like to see what the MAP voltage is over the same RPM range. It looks like the MAP signal is being clipped at about 2500 RPM. I am willing to bet the sensor voltage is being pegged at 5V from 2500 RPM and on. Are you using a stock MAP sensor or 2/3 BAR sensor? It would be better to see an actual vacuum/pressure gauge hooked up. What that reading taken when the engine was under load or just revving it while parked?

-Muzzy
Click to expand...

This is at wide open throttle on the dyno. This is map voltage as measured by the VEC and displayed in inches of vacuum. The voltage is not being clipped in any way. The voltage is pegged at 5 volts from the hit but the voltage goes down as the RPM's go up which shows us the increase in vacuum. I did tap the Roe plenum about 2 inches behind the throttle body and installed a manual guage which matches the data you see in the log so I am confident in the log data. The log data does come from the stock map sensor.

DW
 
I guess I have never see such a consistent amount of vacuum/pressure (for those physicists that say, “There is no such thing as vacuumâ€￾) as RPMs increase. You would think with ten cylinders and 505 cubic inches you would see more of a change. Is that indicative of not enough air being supplied to the supercharger (reaching the CFM limit of the TB)?

-Muzzy
 
That is usually what this indicates. When I see this on the Gen2 Vipers, I install larger throttle bodies and there will be no presence of vacuum behind the throttle bodies; just a good old zero reading. This usually occurs on the cars when we exceed 10 lbs with the Roe unit. This unit is really moving some air! From what I understand, the air is being expelled from the blower faster than it can come in, thus creating the vacuum on the inlet side of the blower. Makes sense to me. When we went from the stock TB to Roe's TB, it showed about 1 inch less vacuum in the plenum........

DW
 
now wouldn't it be interesting to see how much vacuum exists with the X-Metal tb too....

Not trying to cause trouble...just wondering if this would be a good apples to apples comparison... (but let's draw the line there...sure don't want John Hennessey involved...)

Roy
 
Which TB flows more air in the real world

Prof said:
now wouldn't it be interesting to see how much vacuum exists with the X-Metal tb too....

Not trying to cause trouble...just wondering if this would be a good apples to apples comparison... (but let's draw the line there...sure don't want John Hennessey involved...)

Roy
Click to expand...

Just as the dust settles over the TB controversey, Roy comes up with a "real world" test. I think we should wait until both of the ongoing group buys are over and all orders shipped and paid for before we conduct this test.
 
Concur fully!

I don't think the results will be applicable to anyone except those of us that have TMTS's and there is an even more elite sub-set...those with boost well beyond 6 lbs. and shall we add, forged internals!

I think that universe is about, hmmmmm, three.
 
I think that little universe is going to start getting much bigger real soon. There is no such thing as too much horsepower (as long as you have forged internals.)
 
700hpOdyssey said:
I think that little universe is going to start getting much bigger real soon. There is no such thing as too much horsepower (as long as you have forged internals.)
Click to expand...
I want to join that group. I am waiting on Performance By Joe to get back with a estimate. I would love to ship the truck to him over the winter. What a great spring time toy that would make. I am also eagerly watching this saga unfold. My goal is 700 + at the wheels, seeing this snag has me concerned.
 
David Weaver "SnakeDoc" at American Racing Technology is working on overcomming the vacuum issue. Any and all suggestions are appreciated. If we get it figured out, I am going to turn down the blower pulley and increase the boost even more. :rock: I want to see how much hp the Roe blower will make. Stay tuned in, when we find the solution, I will post up the fix.
 
700hpOdyssey said:
David Weaver "SnakeDoc" at American Racing Technology is working on overcomming the vacuum issue. Any and all suggestions are appreciated. If we get it figured out, I am going to turn down the blower pulley and increase the boost even more. :rock: I want to see how much hp the Roe blower will make. Stay tuned in, when we find the solution, I will post up the fix.
Click to expand...

According to Roe the blower is mathamatically capable of producing 19lbs of boost in our engines.:eek: :eek:
 
SrtBrad said:
According to Roe the blower is mathamatically capable of producing 19lbs of boost in our engines.:eek: :eek:
Click to expand...


Then I want 7 more pounds of boost and a Roe intercooler. :rock: Between that and working out the vacuum issue,can us Roe guys dare to expect over 800 horse, maybe 850 foot pounds of torque? :D
 
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Engine results back. No damage to the crank, bearings or engine block.
 
Bone- Quick note; you really should be using the long-life HOAT coolant (orange mopar) in your engine. It is a far superior coolant to the green types, and wont kill your water pump seals. Do a really good flush before you put it back together, and then do another flush a year later as extensively as you can to get any silicates out of the system which have separated from the passage walls.
 
Finally received my bigger Crank Pulley to go with my smaller SC pulley.
Thanks to David Weaver!
American Racing Technology
 

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