48RE Dump valve

fosterriley

fosterriley

Just wanna go fast
Joined
Apr 21, 2015
Messages
169
Got a few questions about 48RE dump valves.

If one was running a large single on the street and wanted to keep a tighter converter for efficiency purposes would you be able to use a dump valve to get on the charger. Then shut it once up on boost or will this cause issues with fluid temp/converter temp. Would the truck try to push through the brakes once closed?
 
It’s not something you’d use while cruising around on the street. It’s intended for spool up in a drag racing application. Using It doesn’t seem to have any major effect on fluid temp.
 
We only use our dump valve when triggering the transbrake. Josh our employee uses one on his race truck without a transbrake but he uses it like w spoolaid at the drag strip. On a lockup converter with full release pressure flow, it raises stall speed about 250 to 300 RPM.
 
Manually shift it to keep smoke down and spoolage up on the street.
 
JP, Yes I I understand that it would not be used during the street driven applications. But it would be used for staging.

Todd, When josh uses that to get on the charger does he release the switch on the launch?
 
Big Blue24 said:
We only use our dump valve when triggering the transbrake. Josh our employee uses one on his race truck without a transbrake but he uses it like w spoolaid at the drag strip. On a lockup converter with full release pressure flow, it raises stall speed about 250 to 300 RPM.
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Correction Will*, When josh uses that to get on the charger does he release the switch on the launch? Sorry about that
 
fosterriley said:
Correction Will*, When josh uses that to get on the charger does he release the switch on the launch? Sorry about that
Click to expand...

Yes, with the low compression 5.9 and single 488, Josh needed to use the dump valve to get the turbo lit at the starting line, otherwise he had to carefully spray the perfect sized spool jet to get it to light.

When he launches, he releases the button similar to releasing a transbrake. The converter doesn't recover immediately meaning it acts extra loose during the first 20 to 30' which lets him launch with more boost than normal and then the converter tightens back up once it get's fully charged with fluid.
 
I'm not sure what other transmission builders offer or sell, but we can and have added dump valves to 47rh, 47re, and 48re models. Our dump valve requires case modifications, it's not a simple VB swap. The dump valve on JP's truck might be 100% VB mods, I haven't seen it in person.
 
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