Whipple Problem... Need Help
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From: Spokane, WA
Heres some helpful info on when to upgrade your injectors. The math is here you just have to get your actual numbers.
There is alot to this. They have their rated flow 39 lbs in your case. Flow rate is rated at a certian psi drop across the injector. Yours as an example would be 39#/hr which is rated to deliver 39# of fuel at 42.5 PSI. The injector will flow 39#/hr as long as the pressure at the supply side, minus the pressure in the manifold is 42.5 psi. In ford systems the psi drop across the injectors is 39.5.
On a blown car your fuel psi must increase 1 psi per pound of boost. Lets say your going to run 14 psi boost, so for fords you should have under boost 39.5 psi + 14 psi boost = 53.5 psi that has be maintained to make the injector work like its rated.
To calculate injector hp ratings roughly you have to know BSFC (brake specific fuel consumption) and on a blown 4.6 liter it is 0.6 actual maybe slightly different but this is close. Take you 8 injectors times 39# = 312 #/hr of fuel divided by the BSFC of 0.6 = 520 hp flywheel. How ever all this changes when you change pumps install a boost a pump. The cobras i have seen with stock injectors 39 # have supported over 550 to the tire. You should be fine with the gt500 pumps and 39# injectors. I am running the ford gt pumps and 39# injectors. The duty cycle will have to be logged you dont want to be maxing the injector out all the time. If you wanted to be on the safe side a 42# or 60# injector will give you room to grow also the Mass air flow sensor maybe close to pegging depending on the sensor you have. My head hurts now
There is alot to this. They have their rated flow 39 lbs in your case. Flow rate is rated at a certian psi drop across the injector. Yours as an example would be 39#/hr which is rated to deliver 39# of fuel at 42.5 PSI. The injector will flow 39#/hr as long as the pressure at the supply side, minus the pressure in the manifold is 42.5 psi. In ford systems the psi drop across the injectors is 39.5.
On a blown car your fuel psi must increase 1 psi per pound of boost. Lets say your going to run 14 psi boost, so for fords you should have under boost 39.5 psi + 14 psi boost = 53.5 psi that has be maintained to make the injector work like its rated.
To calculate injector hp ratings roughly you have to know BSFC (brake specific fuel consumption) and on a blown 4.6 liter it is 0.6 actual maybe slightly different but this is close. Take you 8 injectors times 39# = 312 #/hr of fuel divided by the BSFC of 0.6 = 520 hp flywheel. How ever all this changes when you change pumps install a boost a pump. The cobras i have seen with stock injectors 39 # have supported over 550 to the tire. You should be fine with the gt500 pumps and 39# injectors. I am running the ford gt pumps and 39# injectors. The duty cycle will have to be logged you dont want to be maxing the injector out all the time. If you wanted to be on the safe side a 42# or 60# injector will give you room to grow also the Mass air flow sensor maybe close to pegging depending on the sensor you have. My head hurts now
Heres some helpful info on when to upgrade your injectors. Copied from a Stang site. The math is here you just have to get your actual numbers. For example my fuel consumption is roughly 0.730 according to the online calculator. I will get hard numbers from Mr. Troyer. But by then I'll have my GT500 pumps on and the Zone 5 harness.
"There is alot to this. They have their rated flow 39 lbs in your case. Flow rate is rated at a certian psi drop across the injector. Yours as an example would be 39#/hr which is rated to deliver 39# of fuel at 42.5 PSI. The injector will flow 39#/hr as long as the pressure at the supply side, minus the pressure in the manifold is 42.5 psi. In ford systems the psi drop across the injectors is 39.5.
On a blown car your fuel psi must increase 1 psi per pound of boost. Lets say your going to run 14 psi boost, so for fords you should have under boost 39.5 psi + 14 psi boost = 53.5 psi that has be maintained to make the injector work like its rated.
To calculate injector hp ratings roughly you have to know BSFC (brake specific fuel consumption) and on a blown 4.6 liter it is 0.6 actual maybe slightly different but this is close. Take you 8 injectors times 39# = 312 #/hr of fuel divided by the BSFC of 0.6 = 520 hp flywheel. How ever all this changes when you change pumps install a boost a pump. The cobras i have seen with stock injectors 39 # have supported over 550 to the tire. You should be fine with the gt500 pumps and 39# injectors. I am running the ford gt pumps and 39# injectors. The duty cycle will have to be logged you dont want to be maxing the injector out all the time. If you wanted to be on the safe side a 42# or 60# injector will give you room to grow also the Mass air flow sensor maybe close to pegging depending on the sensor you have. My head hurts now"
"There is alot to this. They have their rated flow 39 lbs in your case. Flow rate is rated at a certian psi drop across the injector. Yours as an example would be 39#/hr which is rated to deliver 39# of fuel at 42.5 PSI. The injector will flow 39#/hr as long as the pressure at the supply side, minus the pressure in the manifold is 42.5 psi. In ford systems the psi drop across the injectors is 39.5.
On a blown car your fuel psi must increase 1 psi per pound of boost. Lets say your going to run 14 psi boost, so for fords you should have under boost 39.5 psi + 14 psi boost = 53.5 psi that has be maintained to make the injector work like its rated.
To calculate injector hp ratings roughly you have to know BSFC (brake specific fuel consumption) and on a blown 4.6 liter it is 0.6 actual maybe slightly different but this is close. Take you 8 injectors times 39# = 312 #/hr of fuel divided by the BSFC of 0.6 = 520 hp flywheel. How ever all this changes when you change pumps install a boost a pump. The cobras i have seen with stock injectors 39 # have supported over 550 to the tire. You should be fine with the gt500 pumps and 39# injectors. I am running the ford gt pumps and 39# injectors. The duty cycle will have to be logged you dont want to be maxing the injector out all the time. If you wanted to be on the safe side a 42# or 60# injector will give you room to grow also the Mass air flow sensor maybe close to pegging depending on the sensor you have. My head hurts now"
There is a lot of math to this and there is no simple yes no answer. IMO you never want to skimp on the fuel system, hence the reason I want to run dual pumps AND larger injectors. Now some tuners prefer to use the smaller injectors and higher fuel pressure for better/easier drive-ability tuning. That is more of an old school of thought and the computers now days are sophisticated enough to where bigger injectors can for the most part still have the same drive-ability as the smaller injector counter parts.
Although this isn't the 310 lph pump in question, this is a visual explanation for pressure vs flow. This is why you can "get away with" running 39# injectors and twin fuel pumps at higher pressure.
Last edited by FATHERFORD; Jan 19, 2010 at 08:34 AM.
The Roush and JDM/Saleen setups come with a 106mm housing. I believe my Vortech came with a 95MM housing.
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From: Spokane, WA
pretty much spot on on the injector side. If you run dual gt-500 pumps you can increase the fuel pressure to 50-60psi and you will still have the volume of the fuel due to the twin pump's.
There is a lot of math to this and there is no simple yes no answer. IMO you never want to skimp on the fuel system, hence the reason I want to run dual pumps AND larger injectors. Now some tuners prefer to use the smaller injectors and higher fuel pressure for better/easier drive-ability tuning. That is more of an old school of thought and the computers now days are sophisticated enough to where bigger injectors can for the most part still have the same drive-ability as the smaller injector counter parts.
Although this isn't the 310 lph pump in question, this is a visual explanation for pressure vs flow. This is why you can "get away with" running 39# injectors and twin fuel pumps at higher pressure.
There is a lot of math to this and there is no simple yes no answer. IMO you never want to skimp on the fuel system, hence the reason I want to run dual pumps AND larger injectors. Now some tuners prefer to use the smaller injectors and higher fuel pressure for better/easier drive-ability tuning. That is more of an old school of thought and the computers now days are sophisticated enough to where bigger injectors can for the most part still have the same drive-ability as the smaller injector counter parts.
Although this isn't the 310 lph pump in question, this is a visual explanation for pressure vs flow. This is why you can "get away with" running 39# injectors and twin fuel pumps at higher pressure.
Your truck currently has one pump.
39# injectors should be all that you would need. The Ford GT pump might still require a boost a pump after a certain spot... There you would have already spent $300 into a pump/boost a pump setup, where another 300 or less can get you a complete dual pump gt-500 setup that will do all your stock shortblock can handle.
Yes the 95mm maf will be FAR superior then the mafia.
BTW the GS341 is basically the same pump our truck comes with(if the 255lph is correct)
39# injectors should be all that you would need. The Ford GT pump might still require a boost a pump after a certain spot... There you would have already spent $300 into a pump/boost a pump setup, where another 300 or less can get you a complete dual pump gt-500 setup that will do all your stock shortblock can handle.
Yes the 95mm maf will be FAR superior then the mafia.
BTW the GS341 is basically the same pump our truck comes with(if the 255lph is correct)
Last edited by FATHERFORD; Jan 19, 2010 at 01:19 PM.
Thread Starter
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From: Spokane, WA
Your truck currently has one pump.
39# injectors should be all that you would need. The Ford GT pump might still require a boost a pump after a certain spot... There you would have already spent $300 into a pump/boost a pump setup, where another 300 or less can get you a complete dual pump gt-500 setup that will do all your stock shortblock can handle.
Yes the 95mm maf will be FAR superior then the mafia.
BTW the GS341 is basically the same pump our truck comes with(if the 255lph is correct)
39# injectors should be all that you would need. The Ford GT pump might still require a boost a pump after a certain spot... There you would have already spent $300 into a pump/boost a pump setup, where another 300 or less can get you a complete dual pump gt-500 setup that will do all your stock shortblock can handle.
Yes the 95mm maf will be FAR superior then the mafia.
BTW the GS341 is basically the same pump our truck comes with(if the 255lph is correct)
Thread Starter
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From: Spokane, WA
id recomend the 10 psi upgrade from whipple for sure. the cobra injectors need to be modified to fit the whipple intake and whipple does this before they are shipped out. If going to 10 psi whipple recomends a .032" plug gap. If you are going to run a 3.125 pulley you will need to put a bigger pulley on your tensioner, the one to use on the tensioner is the idler you removed from the drivers side on the install.
As are pumps. If you can find a good deal on a used pump then go ahead. I'm just warning you in your future plans you will still have to do a boost a pump or a dual fuel pump conversion.... Might as well do it now type of deal.
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From: Spokane, WA
injectors are good for a long long time....
As are pumps. If you can find a good deal on a used pump then go ahead. I'm just warning you in your future plans you will still have to do a boost a pump or a dual fuel pump conversion.... Might as well do it now type of deal.
As are pumps. If you can find a good deal on a used pump then go ahead. I'm just warning you in your future plans you will still have to do a boost a pump or a dual fuel pump conversion.... Might as well do it now type of deal.
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From: Northern Alberta
the instructions from whipple only indicate to gap to .032 if running 10psi+. So i ASSUME the factory gap on the Ford Racing or autolite HT0s would work for 8psi. But honestly gapping them to .032 at 8psi wouldnt hurt...better the gap be at .032 then to big and cause a high RPM missfire.
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From: North Carolina
To whom ever may be intrested here is a GT500 fuel pump assembly on ebay. http://cgi.ebay.com/ebaymotors/ws/eB...EF:MOTORS:1123
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From: Spokane, WA
To whom ever may be intrested here is a GT500 fuel pump assembly on ebay. http://cgi.ebay.com/ebaymotors/ws/eB...EF:MOTORS:1123
Also, if I am not able to get the used 39# injectors that came from whipple, have we determined if the FMS ones will work or not. I dont want to buy them and have them not work. and there are several people who say they will work, and several who say they wont. Which one is it?
Are you really making 427rwhp at only 8psi or are you at 10psi? Also, what pump are you running. I'm just trying to get all the input I can before choosing a pump set up. That link has the gt 500 pump at $350 where a boost a pump is only $200 -250 depending on which one you get, I think either 30 or 40 amp.
Also, if I am not able to get the used 39# injectors that came from whipple, have we determined if the FMS ones will work or not. I dont want to buy them and have them not work. and there are several people who say they will work, and several who say they wont. Which one is it?
Also, if I am not able to get the used 39# injectors that came from whipple, have we determined if the FMS ones will work or not. I dont want to buy them and have them not work. and there are several people who say they will work, and several who say they wont. Which one is it?
That gt-500 is is a DUAL pump unit. You can swap in two 310lph pumps and really have potential for power.
Also people throw around rwhp numbers. Not saying he doesn't have a 427rwhp dyno chart, but his same truck on different dyno could read 410rwhp, on another read 450rwhp. Also every truck is different, one might do 430rwhp and the other with the same mods might do 400rwhp.
Last edited by FATHERFORD; Jan 19, 2010 at 08:32 PM.
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From: North Carolina
I have been on 2 dyno's. One at National Speed in Wilmington NC was 433rwhp and 466lbft tq and the most recent at Fast Lane Motorsports in Benson NC was 427rwhp and 468lbft of tq. Stock pump, 39lb injectors, 8psi. Rev limit is set at 5900 but my shifts are around 4900.