03-26-2017, 09:22 PM | #15 | |
Drives: 2010 2ss ss/rs abm, 2016 2ss/rs hbm Join Date: Feb 2009
Location: N. Phx, Az
Posts: 1,332
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Quote:
Our CCM also control exhaust valves and the magnetic ride if I recall....So that's why it's no longer called FPCM since it controlling more that just the fuel pump.
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URR2SLO - If you're not going fast enough, get out the way......
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03-27-2017, 01:08 AM | #16 | |
Drives: 2015 C7 Z06 M7 Join Date: Dec 2012
Location: So-Cal
Posts: 654
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Now, with falling pressure from the LPFP there is a point where the restrictions between the LPFP and HPFP will prevent complete filling of the HPFP. I haven't tested to determine what pressure/flow that this will begin to occur at, but I have run down to 25psi LPFP pressure without any reduction in flow from the HPFP. I have no intention of testing lower pressure, now with the addition of the ZL1 LPFP along with the Big Bore HPFP and LT4 injectors I was running a minimum LPFP pressure of 40.5 psi @ 730RWHP. |
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03-28-2017, 10:18 AM | #17 | |
Drives: 2001 Audi TT, 2016 Camaro Join Date: May 2016
Location: Eastern Washington
Posts: 833
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Quote:
I will comment also that that local tuners and I have talked about tuning my E-Force in the future and they state that they can tickle the LT1 fuel system to handle power levels up to roughly 620 rwhp without any mechanical upgrades. When I press them, they just smile and state that its one of their trade secrets. They will even warranty their work. (They have done dozens of corvette LT1s already and are now offer an FBO kit through the local Chevy dealer with full factory warranty, so one has to assume they know what they are doing.) My only guess is that they are going beyond the typical HP Tuners tuning capabilities and manipulating the firmware directly(?) Are they possibly managing the HPFP via firmware changes to achieve this? This is way out of my league here, but I am interested in hearing from others on this. |
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03-28-2017, 10:22 AM | #18 |
Drives: 17 SS a8 Join Date: Feb 2010
Location: omaha
Posts: 1,678
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600+hp with gasoline should not be an issue with all stock fuel system.
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dropped a valve in the 6.2. now running a drop in rods and piston 5.3
best et 5.83@121 with the 5.3 http://www.camaro6.com/forums/showthread.php?t=465472 |
03-28-2017, 10:23 AM | #19 | |
Drives: 2016 1SS D1SC Methfed Lowered Wrapd Join Date: Apr 2016
Location: CA
Posts: 632
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Quote:
I guess that would depend on two things... 1. Is there a firmware lock or failsafe that keeps the pumps from working too hard and breaking? 2. could you boost both and achieve what other non DI motors do without mechanical changes? It's a matter of software or a limitation of physics at this point. You'd think with the LT1 out for as long as it has been; they'd find a cost effective solution to all this. Want e85? Cool it'll run you about 10k with cam and fuel + labor. Yay. |
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03-28-2017, 11:00 AM | #20 | |
Drives: 2010 2ss ss/rs abm, 2016 2ss/rs hbm Join Date: Feb 2009
Location: N. Phx, Az
Posts: 1,332
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Quote:
Currently I am at 681rw and I have all stock LT1 high side parts and a ZL1 low side pump. I do have a cam with a 38% fuel lobe though. My injection time is 5.2ms and my high side pressure is 2241psi and my low side drops to 45psi during the pull. I am still playing with the injection timing to see how much more room I have to go to a smaller pulley and more boost. Before the ZL1 pump I was seeing 7.2ms 1700ish high side and 32 low side and power was peaking around 660. I changed the low side pump and it went to 5.8ms while maintaining 45psi and over 2000 high side. Playing with injection timing I am down to 5.2ms and power is peaking at 681rw. So there's a lot to consider when talking about tuning the fuel system.
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URR2SLO - If you're not going fast enough, get out the way......
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03-28-2017, 11:39 AM | #21 |
Drives: 17 SS a8 Join Date: Feb 2010
Location: omaha
Posts: 1,678
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Whoa. Some good info there.
Repeating what you said going from 32psi low side to 45psi low side had a significant improvement in the high side fuel delivery. What all are you doing with your injection timing?
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dropped a valve in the 6.2. now running a drop in rods and piston 5.3
best et 5.83@121 with the 5.3 http://www.camaro6.com/forums/showthread.php?t=465472 |
03-28-2017, 11:41 AM | #22 |
Drives: 2001 Audi TT, 2016 Camaro Join Date: May 2016
Location: Eastern Washington
Posts: 833
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Good comments. I learned something today. I should have stated that my criteria to the tuners was it has to be tuned to 92 octane and no meth or E85.
I am just beginning to understand the "why" of the whole injection timing window restrictions and understand that minor changes are possible, but not a lot of room. (as you said, 6ms. limit.) I've also heard that minor tweaks to the SOI can help a little. I don't plan on changing out the cam, so as a safety factor, I'll probably add the LT4 HPFP myself before the tune. Maybe even the injectors. But I still want to hear from the local tuner how are they accomplishing this level with no changes in the mechanical portion of the fuel system. The electronically controlled relief valve on the HPFP may be the key as you stated. |
03-28-2017, 11:47 AM | #23 |
Drives: 16 Camaro 2SS Join Date: Feb 2017
Location: Chicago
Posts: 214
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What about adding a LS7 lash cap?
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03-28-2017, 12:16 PM | #24 | |
Drives: 2010 2ss ss/rs abm, 2016 2ss/rs hbm Join Date: Feb 2009
Location: N. Phx, Az
Posts: 1,332
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As far as stock cam goes, when boosting I have seen positive results increasing higher rpm and higher airmass areas by 5 to 7 percent.
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03-28-2017, 12:21 PM | #25 |
Drives: 2010 2ss ss/rs abm, 2016 2ss/rs hbm Join Date: Feb 2009
Location: N. Phx, Az
Posts: 1,332
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Heard too many horror stories from the Vette forums. I have not tried it and doubt I will. When I run out I am looking at buying the Lingenfelter big bore pump and whatever injectors may be out there by then. I know there's a ridiculous amount engineering on these DI injectors. That seems like a more reliable way, to me that is.
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03-28-2017, 12:35 PM | #26 |
Drives: 2001 Audi TT, 2016 Camaro Join Date: May 2016
Location: Eastern Washington
Posts: 833
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My first thought was; well you have the sum of the pump curves playing into this. But the small incremental change in pressures from the ZL1 pump to the stock pump at WOT doesn't seem it would account for this.
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03-28-2017, 01:46 PM | #27 | |
Drives: Many C7's Join Date: Apr 2014
Location: Kansas City
Posts: 573
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It only helps in a very narrow range. A Camaro that I was tuning would drop from 80psi to like 35psi under a short dyno pull. And then yes HPFP readings were dropping as well. After House of Boost installed a Boost-a-Pump, the system maintains a full ~80psi on the LP side, and runs exactly my commanded HPFP pressure. However, I see WAY more junk HPFP's that just have no prayer keeping up, then I do LPFPs. |
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03-28-2017, 01:48 PM | #28 | |
Drives: Many C7's Join Date: Apr 2014
Location: Kansas City
Posts: 573
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Quote:
As far as "cam timing" most if not 99% of the cams made for these cars are made for "0" on the cam table. Any change usually results in MORE boost, and LESS power. (aka: flow issues) |
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