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Post by drewz28 on Jan 25, 2006 0:04:33 GMT -5
Ok, my motor is almost done. I need to figure out what size injectors I'll need. Stock LT1 but with 8.5:1 compression and 14 lbs of boost. Stock fuel pump and lines, at least for right now. What do you guys think?
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Post by 1bad2k2ta on Jan 25, 2006 0:12:04 GMT -5
Ok, my motor is almost done. I need to figure out what size injectors I'll need. Stock LT1 but with 8.5:1 compression and 14 lbs of boost. Stock fuel pump and lines, at least for right now. What do you guys think? Hee hee, I think you better upgrade your fuel system, or your gonna go lean, then "pop". ;D Always go bigger than you think you will need. Better a little too big, than a little too small. Since you plan to make 550-600 rwhp, you are going to need at least 60lb/hr injectors. I have Mototron 65lb/hr. I think they are the biggest high impedence injectors out there right now. But I am running 58 psi fuel pressure. Your stock system runs 43 psi, so you will not get as much power for a given injector size. Your stock fuel system is not up to this kind of power requirement. I am running an external Bosch 420lph pump and am nearing its max. |
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Post by Fire67 on Jan 25, 2006 9:32:26 GMT -5
My stock LT1 maxed out my 42lb-hr injectors with 10psi making 450rwhp. Do not run that thing without an upgraded fuel system...
1bad2k2ta is absolutely right, at that kind of boost level your gonna need to upgrade the whole fuel system... Your best bet as of now is to decide a target HP level, add about 50hp to that target and then figure your fuel system accordingly... We can help with that, but its hard to be accurate when the only info you give us is "stock LT1, 8.5:1 compression, with 14psi".
We need to know your supporting mods and power goals to help you accurately.
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Post by drewz28 on Jan 27, 2006 2:00:15 GMT -5
Ok, basicly the car is completly stock. I do have the ATI in line booster fuel pump. P1SC head unit with twin intercoolers. Blew one piston apart already, so I'm dropping the compression with some forged pistons, but the rest of the engine is pretty much stock. 1.6 rockers and a 52mm TB. Car had a new fuel pump put in about 25-30K miles ago. Fuel pressure before the booster pump was 52 psi at idle. Will this be enough with larger injectors or should I just do a new pump?
Target hp is 550 to the wheels, but anthing above 500rwhp will be ok for me.
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Post by 94m6hardtopz on Jan 27, 2006 8:20:59 GMT -5
if you want to run 14lbs and 500+ on 93, you are going to need more fuel. id run 50lb injectors and a fuel system. with 42s and the fuel pump you have you could run race gas at the boost level and be alright, but for pump gas id either pulley it down or run a big fuel system. pump gas and high boost just dont get along.
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Post by drewz28 on Jan 28, 2006 1:22:04 GMT -5
Oh yeah, forgot to mention that. The gas station across the street from my job sells barrows of 110 and 114 octane fully leaded gas. I'll be running that mixed with 91 (yeah, only 91 here in AZ). Will that affect how much I need to build the fuel system?
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Post by 1bad2k2ta on Jan 28, 2006 1:29:42 GMT -5
Oh yeah, forgot to mention that. The gas station across the street from my job sells barrows of 110 and 114 octane fully leaded gas. I'll be running that mixed with 91 (yeah, only 91 here in AZ). Will that affect how much I need to build the fuel system? Leaded gas will destroy your O2 sensors. |
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Post by 94m6hardtopz on Jan 28, 2006 2:00:03 GMT -5
Oh yeah, forgot to mention that. The gas station across the street from my job sells barrows of 110 and 114 octane fully leaded gas. I'll be running that mixed with 91 (yeah, only 91 here in AZ). Will that affect how much I need to build the fuel system? Leaded gas will destroy your O2 sensors. they live a while if you keep the mix about 50/50. |
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Post by 1bad2k2ta on Jan 28, 2006 2:06:27 GMT -5
Leaded gas will destroy your O2 sensors. they live a while if you keep the mix about 50/50. 109 unleaded would be better if you can find it. |
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Post by '68SuperchargedLT1Camaro on Jan 28, 2006 4:24:32 GMT -5
I think 14 psi WITH intercoolers on pump gas will work as long as your static compression ratio is really 8.5 to 1, and as long as you didn't use thicker head gaskets to help get you to this 8.5 to 1 compression. You should run the thinest head gaskets available, even though it will raise the static compression ratio slightly. Which pistons are you using? What is the size of the dish in cc's? Which head gaskets are you using?
At one point I had very close to what you have. This LT1 had 1.6 roller rockers, a bigger throttle body, stock heads with a very small cam (Comp 501), and full exhaust. I was running 11 psi with 9.0 to 1 compression, and NO intercooler. This was in south Texas, during the summer. Absolutely no signs of detonation what so ever. I don't just pull the plugs to check for detonation either. I pull the heads off.
I think you should consider running the injectors that 1BAD2K2TA (Tom) runs. I believe the fuel injectors he is referring to are the Mototron L107's. These are high impedance, 60 pound per hour injectors. Running these will guarantee that you have enough injector, and will allow upgrades in the future without having to upgrade the injectors right away.
Keep in mind, you can use HUGE injectors, and still run lean if the rest of the fuel system isn't up to par.
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Post by 94m6hardtopz on Jan 28, 2006 13:00:18 GMT -5
they live a while if you keep the mix about 50/50. 109 unleaded would be better if you can find it. back in the day i ran 50/50 mix of pump gas and VP C12 and never had a problem. we tuned it with 50/50 C12 and 93 on the dyno, then at the track i ran 50/50 C16 and 93. i never had an 02 crap out. and i did that for years. same on several friends poweradder cars as well, never an issue. |
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Post by impaladave on Feb 14, 2006 7:21:14 GMT -5
I'm running 60# Mototron's and there plenty. I had to upgrade my inline from a T-Rex to a Holley 255 inline. I also have a Walbro 255 with the Racetronix harness. I have plenty of fuel now.
Dave
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Post by Fire67 on Feb 14, 2006 10:40:13 GMT -5
Check into Racetronix for their twin in-tank 255's. You'll definitely need the two 255lph pumps, I prefer pumps plumbed in parallel vs. plumbed one after the other.
You could get by on 50# injectors, but the Mototron 60's are cheaper and will support more power for any future plans.
Higher octane gas, whether it be unleaded or leaded will lower your BSFC so you could get away with the 50's for a long time if you mix race gas.
Their are several website that have injector calculators... You need to give them estimated (flywheel)HP goals and estimated BSFC. I always figure .6bsfc for my blower car here in hot FL on 93octane.
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Post by drewz28 on Jul 18, 2006 0:18:16 GMT -5
Well, I'm doing a Walbro 255 with the racetronics harness and Delphi 50# injectors.
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