Hey guys, I have some fuel system questions I was hoping maybe some of you Viper owners could answer.
My car was harvested of the factory bucket/pump assembly and the design of it is still a little bit of a mystery to me with everything I know about it being from pictures. I've read the thread on upgrading to a gen 3 pump/boost a pump but a few things weren't clear
1) does the factory PUMP itself have a second feed port for the siphon that feeds the bucket, or is there some sort of siphon jet system integrated into the bucket design? I've heard it explained both ways. I assume the former which is what makes upgrading such a pain.
2) I've seen some guys install 255's or even twin pumps into stock buckets, and obviously they lose the siphon feature which feeds the bucket, so how are you keeping the pump submerged when the fuel level is below the top of the bucket? Are you cutting the bottom out and running the pickup outside the bucket? Cutting windows into the bucket?
My setup will require a bypass regulator up front (return system) and since the car will be doing road course/time attack duty, fuel control is is a priority. It also needs to support about 550whp on E85, and to make it all even harder I'm trying to do this on a tight budget.
The Holley billet pump hat for Dodge trucks uses the same top hat style gasket as the Viper, so it'll fit in tank with just trimming/adjustment of the hanger assembly and float rod. It provides provisions for feed/return as well as a wiring bulkhead that can support a 525LPH "hellcat" pump.
The issue with just hanging a big ol' pump in there is fuel control.
Since I don't have the stock bucket, my plan to address this was to simply fab up a stainless steel bucket and then use a Radium siphon jet setup tied to the return to fill the bucket with fuel (the return line would also be re-filling the bucket with fuel). Radium's siphon jet setup is made to provide a crossover for saddle tanks, but filling the bucket is the same concept. It SHOULD work, but no guarantees and I'd likely have to test it out thoroughly with a non flammable solvent seeing if I could starve the bucket with motion.
Plan 2 was to simply run a surge tank, but "simply" really isn't that simple. The first issue becomes what pump hat to use since using the Holley hat AND a surge tank doubles the cost, and either an OEM Viper or Dodge Truck (1/4 the price) pump hat assembly would require a return port to be added and the integrated FPR to be bypassed. Not a big deal, but it's hurdle 1.
Hurdle 2- it is normally considered ideal to use a lift pump that flows at least 1/2 the capacity of the feed pump in the surge tank, which means a 255LPH should work for a 525LPH surge setup.
But already stated, a 255LPH hung in the tank with no siphon assisted bucket or baffling would have no fuel control, which means the pump would likely starve frequently. I know that's the point of the surge tank, but starving the lift pump on every turn I don't think would be very good for pump longevity. Maybe i'm over thinking that, but it just doesn't seem like a good idea to me on a time attack build seeing a lot of G's. Never hurt an in tank walbro personally, but i've killed other (external) pumps from intermittent starvation before.
If you're wondering why i'm not following the old thread and just using a gen 3 pump with a boost a pump and a stock bucket, the main reason is cost. I don't have a stock bucket - $400. Stock gen 3 pumps seem to fetch a premium and I'd still need a boost-a-pump to support my power level (another $300) and then modifications would still have to be made to the factory bucket to provide a return and FPR bypass.
Hydra-mats have been suggested but I've personally seen mixed results on their effectiveness. There's one designed for road course use (it's massive) and it's $1200 by itself.
My car was harvested of the factory bucket/pump assembly and the design of it is still a little bit of a mystery to me with everything I know about it being from pictures. I've read the thread on upgrading to a gen 3 pump/boost a pump but a few things weren't clear
1) does the factory PUMP itself have a second feed port for the siphon that feeds the bucket, or is there some sort of siphon jet system integrated into the bucket design? I've heard it explained both ways. I assume the former which is what makes upgrading such a pain.
2) I've seen some guys install 255's or even twin pumps into stock buckets, and obviously they lose the siphon feature which feeds the bucket, so how are you keeping the pump submerged when the fuel level is below the top of the bucket? Are you cutting the bottom out and running the pickup outside the bucket? Cutting windows into the bucket?
My setup will require a bypass regulator up front (return system) and since the car will be doing road course/time attack duty, fuel control is is a priority. It also needs to support about 550whp on E85, and to make it all even harder I'm trying to do this on a tight budget.
The Holley billet pump hat for Dodge trucks uses the same top hat style gasket as the Viper, so it'll fit in tank with just trimming/adjustment of the hanger assembly and float rod. It provides provisions for feed/return as well as a wiring bulkhead that can support a 525LPH "hellcat" pump.
The issue with just hanging a big ol' pump in there is fuel control.
Since I don't have the stock bucket, my plan to address this was to simply fab up a stainless steel bucket and then use a Radium siphon jet setup tied to the return to fill the bucket with fuel (the return line would also be re-filling the bucket with fuel). Radium's siphon jet setup is made to provide a crossover for saddle tanks, but filling the bucket is the same concept. It SHOULD work, but no guarantees and I'd likely have to test it out thoroughly with a non flammable solvent seeing if I could starve the bucket with motion.
Plan 2 was to simply run a surge tank, but "simply" really isn't that simple. The first issue becomes what pump hat to use since using the Holley hat AND a surge tank doubles the cost, and either an OEM Viper or Dodge Truck (1/4 the price) pump hat assembly would require a return port to be added and the integrated FPR to be bypassed. Not a big deal, but it's hurdle 1.
Hurdle 2- it is normally considered ideal to use a lift pump that flows at least 1/2 the capacity of the feed pump in the surge tank, which means a 255LPH should work for a 525LPH surge setup.
But already stated, a 255LPH hung in the tank with no siphon assisted bucket or baffling would have no fuel control, which means the pump would likely starve frequently. I know that's the point of the surge tank, but starving the lift pump on every turn I don't think would be very good for pump longevity. Maybe i'm over thinking that, but it just doesn't seem like a good idea to me on a time attack build seeing a lot of G's. Never hurt an in tank walbro personally, but i've killed other (external) pumps from intermittent starvation before.
If you're wondering why i'm not following the old thread and just using a gen 3 pump with a boost a pump and a stock bucket, the main reason is cost. I don't have a stock bucket - $400. Stock gen 3 pumps seem to fetch a premium and I'd still need a boost-a-pump to support my power level (another $300) and then modifications would still have to be made to the factory bucket to provide a return and FPR bypass.
Hydra-mats have been suggested but I've personally seen mixed results on their effectiveness. There's one designed for road course use (it's massive) and it's $1200 by itself.
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