LS7 440 high compression - fuel system requirements
#1
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I'm planning on getting a new motor in the next year, and the most attractive setup is an LS7 block (no weight gain and more bore), stroked to 440ci. Because my car is not even close to being a daily driver, I figured maybe I should plan on this being a fairly high compression setup, maybe 13:1, with cam duration in the mid 280's. E85 is available in my area, so I'm wondering, what will I need to do to my fuel system to facilitate this motor? Obviously larger injectors, but should I get a double pumper setup as well, or will my single walbro be sufficient?
Thanks everyone.
Thanks everyone.
#2
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This is what i would do; resleve the ls7 to take the extra power, to 4.185 bore and keep crank to 4.00 stroke, this will give you a 440 Ci that works better in my opinion, keep compression to 12.8 max so you can drive it on street without too much heat problems {compression makes much heat} as for the cam Camhelp@guerragroup.com for $25. you get exactly the rite cam the first time, be ready to fill out long number of questions about your car, do this first as Patrick will help you select the rite parts, he likes light weight valve train etc.
For fuel pump use your Walbro and a second Walbro to come in @ wide open throttle with a micro switch.
You will end up with a fast car you can drive on the street because is tuff to leave home without it, you'll want to show it and hear it and be seen in it, is reality.
Here's a better way to go for cylinder block, get a dry sleeve 6 bolts per cylinder 4.185 bore from Earl and just give them the one you have for core, then get 6 bolts large bore ls7 heads from Mast performance or Texas speed.
For fuel pump use your Walbro and a second Walbro to come in @ wide open throttle with a micro switch.
You will end up with a fast car you can drive on the street because is tuff to leave home without it, you'll want to show it and hear it and be seen in it, is reality.
Here's a better way to go for cylinder block, get a dry sleeve 6 bolts per cylinder 4.185 bore from Earl and just give them the one you have for core, then get 6 bolts large bore ls7 heads from Mast performance or Texas speed.
#3
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I was actually already looking at ERL's line of blocks as well. They seem like a good deal. I guess any more than 4.00 stroke can run into issues with the rings or something? My buddy was telling me about it....But, yea I was planning on having the cam spec'd, I just know right off the bat I want a lot of duration.
As for the second pump, do you mean I could run an inline pump without having to mess with the sending unit, or could I use that Kenne bell boost-a-pump?
I appreciate the advice, man.
As for the second pump, do you mean I could run an inline pump without having to mess with the sending unit, or could I use that Kenne bell boost-a-pump?
I appreciate the advice, man.
#4
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[QUOTE=98Zheadsncam;17146833]I was actually already looking at ERL's line of blocks as well. They seem like a good deal. I guess any more than 4.00 stroke can run into issues with the rings or something? My buddy was telling me about it....But, yea I was planning on having the cam spec'd, I just know right off the bat I want a lot of duration.
As for the second pump, do you mean I could run an inline pump without having to mess with the sending unit, or could I use that Kenne bell boost-a-pump?
I appreciate the advice, man.[/QUOTE
The following may seen like a lot of bla bla bla and a lot of crap, but jobs done rite, have their price and rewards.
Drain all fuel, take the fuel tank off and remove fuel pump assembly, drain all remaining fuel, leave the tank out in full sun for at list a couple of hours {let it get hot} and weld a -10 mail bung to your stock tank, an inline fuel cut off valve, an inline filter, use only -10 feed hose all the way to the pump, coming out of the pump use -6 line, a one way check valve, then joint with factory line, into a -8 braided line to your fuel rails. I use only nylon braided lines for e 85 Earl's is best, IMO.
It would be nice if you can get a return line and a fuel pressure regulator, if you go this route weld an additional -6 bung to your tank opposite to your new fuel line, to keep hot returning gas from outlet of new pump, and just use a -6 line from regulator to tank, for a return line.
Another way to go, tho not as nice but easier is to get two intank pumps and have the second one be turn on by the switch described above.
As for the second pump, do you mean I could run an inline pump without having to mess with the sending unit, or could I use that Kenne bell boost-a-pump?
I appreciate the advice, man.[/QUOTE
The following may seen like a lot of bla bla bla and a lot of crap, but jobs done rite, have their price and rewards.
Drain all fuel, take the fuel tank off and remove fuel pump assembly, drain all remaining fuel, leave the tank out in full sun for at list a couple of hours {let it get hot} and weld a -10 mail bung to your stock tank, an inline fuel cut off valve, an inline filter, use only -10 feed hose all the way to the pump, coming out of the pump use -6 line, a one way check valve, then joint with factory line, into a -8 braided line to your fuel rails. I use only nylon braided lines for e 85 Earl's is best, IMO.
It would be nice if you can get a return line and a fuel pressure regulator, if you go this route weld an additional -6 bung to your tank opposite to your new fuel line, to keep hot returning gas from outlet of new pump, and just use a -6 line from regulator to tank, for a return line.
Another way to go, tho not as nice but easier is to get two intank pumps and have the second one be turn on by the switch described above.
Last edited by CAMSTER; 02-15-2013 at 07:06 AM.
#5
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I ran my 13.3:1 430ci LS7 in my C5 off of the stock fuel system other than changing to an LS3 fuel rail, LS9 injectors and a single Walbro 485 E85 fuel pump. The engine had plenty of fuel supply. The car made 570rwhp with a very mild tune through an unported FAST 102 and stock C5 Z06 exhaust. On E85 and lower fuel demands a big fuel system will overly circulate the fuel adding unneeded heat to the fuel.
#6
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E-85 should love it. You're building the same combo I have on the table - 4.125" stroke with flat tops, right around 13:1. Plenty of room to avoid detonation - the biggest enemy of LS7 sleeves. One local builder told me they've never seen an LS7 sleeve fail without detonation (other than broken pistons, etc.). If you're anywhere close, use a water-meth kit.
Mine is going into a stripped, trailered race-only Firebird.
Mine is going into a stripped, trailered race-only Firebird.
#7
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[QUOTE=CAMSTER;17149096] My 98 fuel tank is a bitch to drop, too. Damn steel tanks. So, according to Jeremy, I can just get away with a new pump and rails...Camster, is there any reason I shouldn't just go that route?
I was [/QUOTE
The following may seen like a lot of bla bla bla and a lot of crap, but jobs done rite, have their price and rewards.
Drain all fuel, take the fuel tank off and remove fuel pump assembly, drain all remaining fuel, leave the tank out in full sun for at list a couple of hours {let it get hot} and weld a -10 mail bung to your stock tank, an inline fuel cut off valve, an inline filter, use only -10 feed hose all the way to the pump, coming out of the pump use -6 line, a one way check valve, then joint with factory line, into a -8 braided line to your fuel rails. I use only nylon braided lines for e 85 Earl's is best, IMO.
It would be nice if you can get a return line and a fuel pressure regulator, if you go this route weld an additional -6 bung to your tank opposite to your new fuel line, to keep hot returning gas from outlet of new pump, and just use a -6 line from regulator to tank, for a return line.
Another way to go, tho not as nice but easier is to get two intank pumps and have the second one be turn on by the switch described above.
The following may seen like a lot of bla bla bla and a lot of crap, but jobs done rite, have their price and rewards.
Drain all fuel, take the fuel tank off and remove fuel pump assembly, drain all remaining fuel, leave the tank out in full sun for at list a couple of hours {let it get hot} and weld a -10 mail bung to your stock tank, an inline fuel cut off valve, an inline filter, use only -10 feed hose all the way to the pump, coming out of the pump use -6 line, a one way check valve, then joint with factory line, into a -8 braided line to your fuel rails. I use only nylon braided lines for e 85 Earl's is best, IMO.
It would be nice if you can get a return line and a fuel pressure regulator, if you go this route weld an additional -6 bung to your tank opposite to your new fuel line, to keep hot returning gas from outlet of new pump, and just use a -6 line from regulator to tank, for a return line.
Another way to go, tho not as nice but easier is to get two intank pumps and have the second one be turn on by the switch described above.
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#8
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I'm planning on getting a new motor in the next year, and the most attractive setup is an LS7 block (no weight gain and more bore), stroked to 440ci. Because my car is not even close to being a daily driver, I figured maybe I should plan on this being a fairly high compression setup, maybe 13:1, with cam duration in the mid 280's. E85 is available in my area, so I'm wondering, what will I need to do to my fuel system to facilitate this motor? Obviously larger injectors, but should I get a double pumper setup as well, or will my single walbro be sufficient?
Thanks everyone.
Thanks everyone.
#9
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[QUOTE=98Zheadsncam;17149285]Thats a real big pump Jeremy is using full time, it is him IMO circulating too much fuel, what about a 260 Walbro full time and another one on demand, is works for me. [I'm using Weldons] now hear me out, The big pump works for him too, however why run such a big pump full time while just driving around or at the stop light, is your call tho, you are been shower by different ways to go about it, is just a great forum. What can i say, RPM builds my trannie and does a great BTW.
Last edited by CAMSTER; 02-16-2013 at 08:43 AM.