jgkurz Posted August 13, 2008 Share Posted August 13, 2008 Hi Folks, I decided to verify that my EFI pump was still up to the task and wanted to share the results. I use a Walbro 255lph pump model GSL392. I found the attached flow chart and determined I'm still in the safe envelope, but just barely. Using the calculator on the bottom of this page (http://www.rceng.com/technical.aspx) I determined that my car will require 52.33 lb/hr (550 cc/min) of fuel flow for each injector. I then converted 52.33 lb/hr to GPH which is 8.72 then multiplied by 6 for each cyl. My peak pressure would be 43.5 base + 26psi boost = 69.5 psi. If all this math is correct, my total flow needed at 524bhp would be 52.32 GPH @ 70psi. I'm not too worried about amp draw since I have a faily robust 140amp alternator and battery. According to the chart I'm still within spec of my pump. Whew….! I did learn that I'm maxed out on my fuel filter, injectors, pump and turbo... -John Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted August 13, 2008 Share Posted August 13, 2008 Nice John! You could always put in larger injectors and lower your base fuel pressure if you start running out of fuel. What is your duty cycle on your current 550cc injectors? BTW, did you get a roll bar in your car? Justin Quote Link to comment Share on other sites More sharing options...
jgkurz Posted August 13, 2008 Author Share Posted August 13, 2008 Nice John! You could always put in larger injectors and lower your base fuel pressure if you start running out of fuel. What is your duty cycle on your current 550cc injectors? BTW, did you get a roll bar in your car? Justin I do plan on putting in larger injectors but if I'm going to make the investment I might as well go E85 capable. Today, at peak power, I'm at about 95% duty cycle. That works for a quick dyno pull or the drag strip but not for any type of sustained power. I would like to be no higher than 80% at peak power so the injectors stay nice a cool and are well under saturation. For E85 I will likely buy 1200cc/min injectors and go full sequential injection instead of batch-fire. If get the parts necessary to run E85 I will also keep my ability to run gasoline. Idling on gas will obviously be an issue to work through. No, I didn't buy a roll bar. I have a custom design in mind but haven't had the time to pursue it further. On a side note, if I buy a bigger EFI pump and go -10 on all my fuel line will I still be limited by the pump inlet size on my fuel tank? I don't want to go to a fuel cell. Maybe the OEM tank can be modified with a larger outlet? Later, Quote Link to comment Share on other sites More sharing options...
JustinOlson Posted August 13, 2008 Share Posted August 13, 2008 I'm sure you could modify the fuel tank for a larger outlet! I imagine you won't have much issue with 1200cc injectors on gas w/ sequential injections. They'd behave just like 600cc injectors batch fired. I'd go with RC's or these from racetronics: http://www.racetronix.com/INJL120.html If you want to borrow the tubing bender your more then welcome to it. I have a 1-5/8" die set for it Justin Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 13, 2008 Share Posted August 13, 2008 I do plan on putting in larger injectors but if I'm going to make the investment I might as well go E85 capable. Today, at peak power, I'm at about 95% duty cycle. That works for a quick dyno pull or the drag strip but not for any type of sustained power. I would like to be no higher than 80% at peak power so the injectors stay nice a cool and are well under saturation. For E85 I will likely buy 1200cc/min injectors and go full sequential injection instead of batch-fire. If get the parts necessary to run E85 I will also keep my ability to run gasoline. Idling on gas will obviously be an issue to work through. No, I didn't buy a roll bar. I have a custom design in mind but haven't had the time to pursue it further. On a side note, if I buy a bigger EFI pump and go -10 on all my fuel line will I still be limited by the pump inlet size on my fuel tank? I don't want to go to a fuel cell. Maybe the OEM tank can be modified with a larger outlet? Later, Hi John.. Those numbers look correct to me - if you are going to E85, you might think about just going to 150lb injectors - they seem to be easier to come by and should have plenty of capacity. I was able to get mine to idle on both gas and E85 in full sequential mode. For gas you can always drop the static pressure down, too - I was able to go as low as 29psi static rail pressure on gas and they still worked fine. I'm running 38psi static with E85 now. I did go ahead and modify my stock tank when I switched to E85. You will want to drop the tank and have it cleaned and internally coated with an alcohol resistant coating before running E85 (they used "red kote" on mine as I recall)- it appears that many of the stories involving E85 ruining fuel pumps have more to do with the E85 loosening old varnish and deposits in old tanks, which subsequently gets sucked into the pump. I added a rear sump with two -8 outlets, each feeding one of my two pumps. Quote Link to comment Share on other sites More sharing options...
jgkurz Posted August 13, 2008 Author Share Posted August 13, 2008 Hi John..Those numbers look correct to me - if you are going to E85, you might think about just going to 150lb injectors - they seem to be easier to come by and should have plenty of capacity. I was able to get mine to idle on both gas and E85 in full sequential mode. For gas you can always drop the static pressure down, too - I was able to go as low as 29psi static rail pressure on gas and they still worked fine. I'm running 38psi static with E85 now. I did go ahead and modify my stock tank when I switched to E85. You will want to drop the tank and have it cleaned and internally coated with an alcohol resistant coating before running E85 (they used "red kote" on mine as I recall)- it appears that many of the stories involving E85 ruining fuel pumps have more to do with the E85 loosening old varnish and deposits in old tanks, which subsequently gets sucked into the pump. I added a rear sump with two -8 outlets, each feeding one of my two pumps. Great info Tim. I would definitely go 150lb injectors if I could still idle and pass emissions on gas. I use the DSM style RC injectors now. The largest RC makes in that style is 104 LBS / HR @ 43.5 PSI. I will need to modify my fuel rail and possibly my intake manifold if I go to another style. Interesting point on the pump failures. I never thought about having my tank coated. Two smaller pumps rather then a single huge pump also has it's advantages. Running a single -10 would be too big now that I think of it. Do you have a picture of your modified tank outlet? Quote Link to comment Share on other sites More sharing options...
TimZ Posted August 14, 2008 Share Posted August 14, 2008 Great info Tim. I would definitely go 150lb injectors if I could still idle and pass emissions on gas. I use the DSM style RC injectors now. The largest RC makes in that style is 104 LBS / HR @ 43.5 PSI. I will need to modify my fuel rail and possibly my intake manifold if I go to another style. Interesting point on the pump failures. I never thought about having my tank coated. Two smaller pumps rather then a single huge pump also has it's advantages. Running a single -10 would be too big now that I think of it. Do you have a picture of your modified tank outlet? Unfortunately I don't have a pic handy, but it looks pretty similar to the one in this post: http://forums.hybridz.org/showthread.php?t=119761 Another nice thing about running two pumps is I can stage them such that the second one only comes on when I exceed a preset boost level, so it's quiet at idle. Quote Link to comment Share on other sites More sharing options...
ktm Posted August 15, 2008 Share Posted August 15, 2008 I did go ahead and modify my stock tank when I switched to E85. You will want to drop the tank and have it cleaned and internally coated with an alcohol resistant coating before running E85 (they used "red kote" on mine as I recall)- it appears that many of the stories involving E85 ruining fuel pumps have more to do with the E85 loosening old varnish and deposits in old tanks, which subsequently gets sucked into the pump. A filter before the pump inlet should solve that problem. However, you'll lean out from starvation and it only takes once under boost. Quote Link to comment Share on other sites More sharing options...
510six Posted August 15, 2008 Share Posted August 15, 2008 The previous setup on my car used two 1600cc Bosch methanol compatable injectors, they can modify the injectors for 11mm O rings.Six of these will be used using 100% E85 http://www.fiveomotorsport.com/Injector_SetsMODS.asp#cng150 A very good methanol/ alcohol compatable external fuel pump is the Bosch 044 unit.http://www.jayracing.com/index.php?main_page=product_info&cPath=2_5&products_id=1 I am planning on running two -6 lines feeding a stainless steel fuel rail using two 044 Bosch pumps with a -8 return to a fuel cell. http://www.cardomain.com/member_pages/show_image.pl?bg=FFFFFF&image=http://memimage.cardomain.com/member_images/7/web/2071000-2071999/2071134_25_full.jpg MSD makes these fuel rail components, they are full alcohol compatable(if a bit pricy)http://www.msdfuelinjection.com/efi_accessories.html http://www.pirate4x4.com/tech/billavista/PDFs/MSd%20fuel%20management.pdf The pumps will have the voltage reduced to 6 volts until boost is reached via a 300zxtt pump voltage limiter. Quote Link to comment Share on other sites More sharing options...
woldson Posted August 15, 2008 Share Posted August 15, 2008 OHHH this is a sweet thread!! Quote Link to comment Share on other sites More sharing options...
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