RACETRONIX DUAL GSS-340's
03-02-2005, 06:55 PM
#1
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Thread Starter
RACETRONIX DUAL GSS-340's
Attached find 2 Excel graphs. First graph stock 340M versus 340ME (epoxied). Second graph dual 340M's versus dual 340ME's. Dual 340's can support 1500 HP @ 50 psig. Regards to all - GREG
03-03-2005, 11:39 PM
#3
Supporting Vendor
Originally Posted by qwiketz
greg, are there any adverse effects to having the pump epoxied? Those are some great high psi #'s.
If you require high pressure support there are ways for us to recalibrate the bypass valve without disabling it entirely. Most often two GSS340M's will support more HP than most people need w/o modification. If you need to operate at pressures where the bypass valve comes into play you must really sit down and re-think your injector sizing. Operating the fuel system at 3-4 bar is recommended.
03-04-2005, 01:32 AM
#4
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Originally Posted by Racetronix
If there is a restriction it could cause a fuel line to blow off or stall the pump's armature and cause a fuse to blow etc.
If you require high pressure support there are ways for us to recalibrate the bypass valve without disabling it entirely. Most often two GSS340M's will support more HP than most people need w/o modification. If you need to operate at pressures where the bypass valve comes into play you must really sit down and re-think your injector sizing. Operating the fuel system at 3-4 bar is recommended.
If you require high pressure support there are ways for us to recalibrate the bypass valve without disabling it entirely. Most often two GSS340M's will support more HP than most people need w/o modification. If you need to operate at pressures where the bypass valve comes into play you must really sit down and re-think your injector sizing. Operating the fuel system at 3-4 bar is recommended.
How are the pumps epoxied? And are both pumps running at the same time or is the second pump fired at X boost level?
03-04-2005, 08:45 AM
#5
Melting Slicks
I am also curious about the epoxied pumps.. I am running 83lb/hr injectors hence one of the reasons was that I did not want to operate in high pressure as stated. I have been wondering how the pumps were going to react in the case of pressure spikes.. I was informed that each pump has its own anti back up valve to keep one pump from over powering the other or if only one pump at a time is used at lower boost, to keep the pump that is not running from letting pressure and fuel return to the tank. I have seen one way vlaves that can be used inline on the feed line would these be worthwhile insurance incase of a pump stall etc..? thanks!
Chris
Chris
03-04-2005, 09:05 AM
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Originally Posted by lcvette
I am also curious about the epoxied pumps.. I am running 83lb/hr injectors hence one of the reasons was that I did not want to operate in high pressure as stated. I have been wondering how the pumps were going to react in the case of pressure spikes.. I was informed that each pump has its own anti back up valve to keep one pump from over powering the other or if only one pump at a time is used at lower boost, to keep the pump that is not running from letting pressure and fuel return to the tank. I have seen one way vlaves that can be used inline on the feed line would these be worthwhile insurance incase of a pump stall etc..? thanks!
Chris
Chris
Chris as far as I know all pumps have a check valve in them. This would prevent backflow from the pump that is running into the pump that is not running. ZR1's use double pumps mounted on the sending unit assembly stock from GM. Their secondary pump turns on only when the secondary air port is opened. There is no other external check valves on these systems. But like you I am curious about the 340ME pumps. I am currently running a single large Bosch in my car which is mounted inside the tank. I got away from the dual inline pump setup after one failure sometime ago.
03-04-2005, 01:10 PM
#7
Melting Slicks
yeah.. I hear alot of people syaingt hat they are not impressed with the parallel intank setups, and unless the two pumps have a negative effect on each other as far as longevity of pump life goes, i think you would be facing the same issues with a single larger pump which could also fail.. granted with 2 pumps you increase your chances, and i can see the arguement that with only one pump running you may not know it until it is too late, but perhaps a pair of flow sensors could be used in conjuynction with a failsafe system like the fuel pressure safety switch on nitrous setups... just thinking out loud again..lol
Chris
Chris
03-04-2005, 03:46 PM
#9
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I run two aeromotive A1000 pumps that each have their own sump at the tank. One runs all of the time and is controlled by the aeromotive controller that slows it down at low rpm to prevent cavitation in the tank. The secondary pump has a separate check valve that keep fuel from backing up into it. The secondary pump turns on via a solenoid that is switched by two adjustable boost pressure switches (set up in duplicate in case one switch becomes inoperable). In order to get two big pumps like this to operate without causing a huge pressure spike when the secondary pump turns on you'll need to gauge exactly when the primary pumps runs out of capacity and then adjust your secondary pump to activate at that point. Or, the better solution is to purchase the larger fuel regulator that Aeromotive and others sell that has a 8AN return line to the tank. My two sumps junction at the back of the car into a 10AN line and then split again before entering the fuel rails into 6AN lines.
Last edited by TONYDEE64; 03-04-2005 at 03:48 PM.
03-04-2005, 06:23 PM
#10
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Thread Starter
If you go back and look at the thread I posted earlier on the 340's you can see my thinking on series vs parallel and the 'risks' of epoxying the pump(s) relief valve.
Racetronix is correct about proper injector sizing however many of us (1985 thru 1993) are 'stuck' with GM's Simultaneous Injection and stuck with 30 pounders if we want to pass a sniffer test. 30 pounders with a FMU and proper pump head can support 650 crank HP (a 30 becomes a 42 at around 80 psi). My choice to supply fuel at 80 psi rail pressure (for up to 650 HP) would be the 340 feeding a 392. It's smooth, has very low amp draw, won't overload your regulator with too much volume, and very reliable. In series the two pumps are coasting even at 80 psig and should easily deliver 2000 hours. That graph is in the previous post.
For whatever reason you need run two 340's in parallel they can be easily 'Y'ed together. I'm making a new foot plate to hold two on existing tree. The two can feed the stock 3/8" fuel line and support 1500 HP. You can run 1 or 2 at a time with the built-in checkvalves. TONYDEE64 is correct though about turning on the second pump and creating a spike.
Finally if you need just a little more fuel at say 70 psi because of the FMU and you only want or need one 340 the epoxy is an easy fix. However, as I warned earlier you must use an epoxy such as Smooth-On Metalset which is unaffected by gasoline.
In the final analysis I like the 340 feeding the 392 for most applications. Regards Greg
Racetronix is correct about proper injector sizing however many of us (1985 thru 1993) are 'stuck' with GM's Simultaneous Injection and stuck with 30 pounders if we want to pass a sniffer test. 30 pounders with a FMU and proper pump head can support 650 crank HP (a 30 becomes a 42 at around 80 psi). My choice to supply fuel at 80 psi rail pressure (for up to 650 HP) would be the 340 feeding a 392. It's smooth, has very low amp draw, won't overload your regulator with too much volume, and very reliable. In series the two pumps are coasting even at 80 psig and should easily deliver 2000 hours. That graph is in the previous post.
For whatever reason you need run two 340's in parallel they can be easily 'Y'ed together. I'm making a new foot plate to hold two on existing tree. The two can feed the stock 3/8" fuel line and support 1500 HP. You can run 1 or 2 at a time with the built-in checkvalves. TONYDEE64 is correct though about turning on the second pump and creating a spike.
Finally if you need just a little more fuel at say 70 psi because of the FMU and you only want or need one 340 the epoxy is an easy fix. However, as I warned earlier you must use an epoxy such as Smooth-On Metalset which is unaffected by gasoline.
In the final analysis I like the 340 feeding the 392 for most applications. Regards Greg
03-04-2005, 08:23 PM
#11
Melting Slicks
Greg,
Ya gotta tell us what this epoxy does and how it is used.. im stumped trying to figure it out unless your say to actually open or make larger the pump outlet neck.
as far as running two in parallel.. I am running twin GSS340's (both with Racetronix hot wire kits for C4's) with -6 feeds for both, Y into -10 and through a larger barry grant High Pressure filter -10 both ends, then into the large aeromotive A1000 regulator, -10 inlet, and a Y and -6 outlets afterwards feeding each of the rails. return line is a -6 which seems to handle base fuel pressure at idle when steady which is when the most amount of fuel actually is returned to the tank. for now I will be running both pumps all the time and from simply letting the recirculate.. i have not seen any issues with pressure stability or spiking.
how much of an adverse affect with running both pumps all the time have on the fuel.. I have read that it will boil the fuel, heat it up, etc etc.. is there any data which supports this?
thanks,
Chris
Ya gotta tell us what this epoxy does and how it is used.. im stumped trying to figure it out unless your say to actually open or make larger the pump outlet neck.
as far as running two in parallel.. I am running twin GSS340's (both with Racetronix hot wire kits for C4's) with -6 feeds for both, Y into -10 and through a larger barry grant High Pressure filter -10 both ends, then into the large aeromotive A1000 regulator, -10 inlet, and a Y and -6 outlets afterwards feeding each of the rails. return line is a -6 which seems to handle base fuel pressure at idle when steady which is when the most amount of fuel actually is returned to the tank. for now I will be running both pumps all the time and from simply letting the recirculate.. i have not seen any issues with pressure stability or spiking.
how much of an adverse affect with running both pumps all the time have on the fuel.. I have read that it will boil the fuel, heat it up, etc etc.. is there any data which supports this?
thanks,
Chris
03-05-2005, 06:24 AM
#12
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Thread Starter
340ME's
Icvette see attached photo. No alteration to discharge or their checkvalves. Epoxy simply covers the spring loaded relief valve off to the side of the discharge. I used a toothpick to push the epoxy into the hole and then for good measure covered the top entirely.
Running two 340's in parallel (stock or modified) is a perfect application for SuperPumper II. SuperPumper II utilizes 3 inputs: fuel rail pressure, manifold pressure, and engine RPM. You 'dial-in' whatever fuel rail pressure you need at whatever boost level and/or RPM and the controller does the rest: ramping up or down the pump(s) as necessary.
Most of the energy that any pump uses is turned into heat to overcome frictional losses. You can measure the ampere draw, turn it into watts and watts into BTU's. Then if you were an engineer you might figure how much heat is transferred to the fuel. Sounds like a good exercise for TJ
. Anyhow I doubt the two pumps could heat the fuel enough to be a problem - the fuel tank is a pretty big radiator.
If you run the pumps continously there are no fuel spike problems. The problem with running two pumps in parallel continously is the rail pressure at idle being too high. As Jack from Racetronix mentioned, the return line is not big enough to relieve the volume of two pumps fast enough to maintain say 40 psi.
By the way, the 3/8" id supply fuel line to the injector rails is more than big enough to handle all the power you can possibly make. I know that is contrary to what a lot of folks believe but it's true and easily verified. The difference in 'head' losses of a 3/8" line versus a say 1/2" line at 125 GPH (that's enough flow to support 1500 HP) is about 13' per 100 feet at 60F (less at higher temperatures). Let's say we have 20 feet of 3/8" tubing from the fuel tank to the rail - that means the head loss in feet is 1/5 of 13 or 2.6 feet. 1 psi = 2.31 feet of water (gasoline is even less). So if there were a 2 psi drop in fuel pressure from the fuel tank to the rail that would be very generous and conservative all things being considered. If you can't handle a 2 psi drop in fuel pressure at 125 GPH then by all means go bigger LOL !!!
Hope I didn't bore you all - Greg
PS - How do you get a photo to show up w/o being an attachment?
Running two 340's in parallel (stock or modified) is a perfect application for SuperPumper II. SuperPumper II utilizes 3 inputs: fuel rail pressure, manifold pressure, and engine RPM. You 'dial-in' whatever fuel rail pressure you need at whatever boost level and/or RPM and the controller does the rest: ramping up or down the pump(s) as necessary.
Most of the energy that any pump uses is turned into heat to overcome frictional losses. You can measure the ampere draw, turn it into watts and watts into BTU's. Then if you were an engineer you might figure how much heat is transferred to the fuel. Sounds like a good exercise for TJ
. Anyhow I doubt the two pumps could heat the fuel enough to be a problem - the fuel tank is a pretty big radiator.If you run the pumps continously there are no fuel spike problems. The problem with running two pumps in parallel continously is the rail pressure at idle being too high. As Jack from Racetronix mentioned, the return line is not big enough to relieve the volume of two pumps fast enough to maintain say 40 psi.
By the way, the 3/8" id supply fuel line to the injector rails is more than big enough to handle all the power you can possibly make. I know that is contrary to what a lot of folks believe but it's true and easily verified. The difference in 'head' losses of a 3/8" line versus a say 1/2" line at 125 GPH (that's enough flow to support 1500 HP) is about 13' per 100 feet at 60F (less at higher temperatures). Let's say we have 20 feet of 3/8" tubing from the fuel tank to the rail - that means the head loss in feet is 1/5 of 13 or 2.6 feet. 1 psi = 2.31 feet of water (gasoline is even less). So if there were a 2 psi drop in fuel pressure from the fuel tank to the rail that would be very generous and conservative all things being considered. If you can't handle a 2 psi drop in fuel pressure at 125 GPH then by all means go bigger LOL !!!
Hope I didn't bore you all - Greg
PS - How do you get a photo to show up w/o being an attachment?
04-16-2005, 04:13 AM
#15
Supporting Vendor
Originally Posted by tjwong
How are the pumps epoxied? And are both pumps running at the same time or is the second pump fired at X boost level?
Depending on the application, we can stage the pumps or have them running all the time. For FI applications we usually set the second pump to come on at a certain boost level using a Hobbs pressure switch. On a car using N2O we usually activate the second pump with the arming switch. The Racetronix PnP DP harness allows you to select which pump is primary and which is secondary at any time by simply changing a jumper connector. Any form of activation can be used and interfaced to the harness.
