12-08-2019, 09:44 PM | #1 |
Drives: 18 1SS 1LE HyperBlue Join Date: Aug 2018
Location: Twin Cities, MN
Posts: 612
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Verifying My Work - LT1 w/ LT4 HPFP & Lash Cap
last year in my winter build, I put on my s/c, LT4 HPFP, LT4 injectors, but installed the pump on the LT1 with just one factory gasket. No lash cap.
On long pulls, I can see my rail pressure will drop and injector cycle will open up some, so both me and my tuner agree I am probably out of HP Fuel Pressure. Now I do run meth on top of everything so I am still feeding it, but would like to try and feed it more E85 if I can. And FYI - my car is a 1LE so it has the larger flow low side pump, but it is just about out of flow also. I am trying to avoid doing a cam swap, so thus far the plan this winter is a DSX aux fuel pump on the low side, and then I was planning to check my LT4 HPFP stroke. I am not trying to get a ton more flow, just maybe 10%. That being said - has anyone run a lash cap on the LT1 cam with the LT4 HPFP? I know some have bottomed the pumps out / broken the bolts using the .080" shims, but has anyone gone thru the process to 100% utilize the LT4 pump? I have read the article on the CorvetteForums, but it shows little on what configurations work?
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2018 1SS 1LE / HBM - ECS Novi 1500 S/C Tuned by Carl @ CJ Tunes
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12-08-2019, 10:29 PM | #2 |
BAMF SS
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How much power were you trying to make?
I would honestly hit it with a little more meth before trying a lash cap on a factory cam.. just my .02
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2016 1SS A8: FBO + Circle D + P1X + Meth + Tuned by Pray Performance
Stock Longblock 800 SAE rwhp. 9.4 @ 145 mph. |
12-08-2019, 10:45 PM | #3 |
Drives: 17 SS a8 Join Date: Feb 2010
Location: omaha
Posts: 1,678
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Just going off memory but I don’t think a lash cap does anything to make a lt4 pump flow more. It just moved the piston up in the stroke and may risk bottoming out the piston if it isn’t just right. I had some posts a long time ago about it.
The lash cap is suppose to help with the smaller base circle high fuel pump lobe cams. Without it you have some wasted cam lobe where the piston isn’t moving.
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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 |
12-09-2019, 05:07 AM | #4 | |
Drives: 1997 Camaro SS LT4 Join Date: Jan 2019
Location: Deltona, FL
Posts: 47
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This may be helpful.
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2018 Camaro 2SS M6 Hot Wheels,Edelbrock 2650, Hurst Short Throw Shifter. Production Number 90
1997 Camaro SS M6 LT4 tribute |
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12-09-2019, 07:40 AM | #5 |
Drives: 2017 50th Anniversary 2SS Join Date: Sep 2016
Location: Jacksonville, FL
Posts: 930
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What about lingenfelter HPFP? Isn’t it good for about 10% more high side flow?
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12-09-2019, 09:45 AM | #6 |
Drives: 2016 1SS NFG A8 Join Date: Aug 2017
Location: 46804
Posts: 6,764
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Yes the LPE big bore is worth another 10% in flow volume. I was out the other night when the temps hit the 30's, boost hit 11 psi, and I still had enough fuel system on E67 and no meth. Normally I see around 9psi above 50 degrees.
The LPE has never been a popular choice. In the end it isn't any more expensive then the LT4 + a Meth kit. I believe it's not popular because the early version was not compatible with bigger fuel lobe cams larger then 32%. So the LT4 with a 38% lobe would end up out flowing the LPE pump. Most seem to go right to a cam swap for more fuel. If you want to run a stock cam with E85, then a LPE pump will free up some headroom. I also didn't need a Auxillary pump. My fuel system: LT4 injectors LPE big bore HPFP LT4 low side with JMS booster This fuel setup is so far is working well. I wont push past 11-12psi tops on stock pistons, so i dont plan on touching it unless I do rod/pistons.
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
12-09-2019, 10:39 AM | #7 | |
Dyno Show Queen LOL
Drives: 16 SS & 17 ZL1 Both Yellow Join Date: Jan 2014
Location: Houston
Posts: 4,343
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Quote:
I would ask MTI performance in Houston I know they messed with lash caps for ages they might be nice enough to help!
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Kong Ported 2650, Crawford Racing Port Injection, Weapon X 112mm Adapter, NW112mm TB, Livernois Ported LT4 Heads, Lingenfelter GT32 stealth cam, Haltech Elite, and Carbon by Trufiber |
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12-09-2019, 02:34 PM | #8 |
Drives: 18 1SS 1LE HyperBlue Join Date: Aug 2018
Location: Twin Cities, MN
Posts: 612
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I really am not doing this to pursue more power - I am content with the power level I am at for street use (700whp), I just want to get that power level on fuel delivery and not require the meth to keep it fed. I will still use the meth for temp control, but I would like to not have to worry about loosing a meth pump and detonating the engine.
I am curious if at one point in the pump stroke if the pumps flow more (IE - in the low / middle / high part of the stroke). I do know some places machine down the valley covers by .030" to get the pumps to sit closer to the cam when running aftermarket cams. I am not apposed to running a lash cap and making a spacer too (IE - a .080" lash cap and a .050" spacer)
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2018 1SS 1LE / HBM - ECS Novi 1500 S/C Tuned by Carl @ CJ Tunes
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12-09-2019, 05:16 PM | #9 |
Drives: 18 1SS 1LE HyperBlue Join Date: Aug 2018
Location: Twin Cities, MN
Posts: 612
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E-Content in Minnesota can vary from 50-85% by law, so the thing about trying to hit / maintain a certain number is that all the variations in fuel here. Even premium 91,92 or 93 can vary from 5-15%.
I can monitor by fuel sensor now, and if I am under E72ish I do not get any lean over on the rail pressure, but at about E65 my flex tune starts pulling timing, so it has a pretty narrow window that is not real easy to hit (I spent all last year trying to target E70-75). I just want to get it where I can rely on the fuel system to keep it fed. I have contemplated a cam swap, but am trying to avoid dropping the oil pan / pulling the engine. Im not afraid of the cost or the work, just trying to keep it a "Keep It Simple Stupid" upgrade.
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2018 1SS 1LE / HBM - ECS Novi 1500 S/C Tuned by Carl @ CJ Tunes
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12-09-2019, 05:33 PM | #10 |
Drives: 2016 1SS NFG A8 Join Date: Aug 2017
Location: 46804
Posts: 6,764
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You are not going to keep it fed on that fuel system without relying on meth. You will need a cam or LPE pump. Those are your 2 options. Cam makes the most sense to me and provide the most fuel headroom, but then you might as well do drop in pistons.
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
12-09-2019, 09:06 PM | #11 | |
Drives: 18 1SS 1LE HyperBlue Join Date: Aug 2018
Location: Twin Cities, MN
Posts: 612
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Quote:
We are addressing the low side with the DSX aux pump
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2018 1SS 1LE / HBM - ECS Novi 1500 S/C Tuned by Carl @ CJ Tunes
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12-10-2019, 09:07 AM | #12 | |
Drives: 2016 1SS NFG A8 Join Date: Aug 2017
Location: 46804
Posts: 6,764
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Quote:
__________________
2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
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12-10-2019, 09:50 AM | #13 |
Drives: 18 1SS 1LE HyperBlue Join Date: Aug 2018
Location: Twin Cities, MN
Posts: 612
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Heater & King - thanks - this changes my direction completely. The work on everything didn't intimidate me at all other than the oil pump alignment.
However this makes me wonder with Lethal's current situation ?
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2018 1SS 1LE / HBM - ECS Novi 1500 S/C Tuned by Carl @ CJ Tunes
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12-10-2019, 10:40 AM | #14 |
Drives: 2016 1SS NFG A8 Join Date: Aug 2017
Location: 46804
Posts: 6,764
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What's his current situation? Last I knew he tore his motor down because the chain tensioner went south, but he could of just fixed it and put it back together...instead he rebuilt the entire engine. I haven't followed him much since.
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2016 NFG 1SS A8
Options-2SS Leather/NPP Perf. mods-Whipple 2.9/Fuel System/Flex Fuel/103mm TB/Rotofab Big Gulp/Cat Deletes/Corsa NPP Per. times- 10.5 @ 137 w/ 1.8 60ft Full weight on 20's 1200DA |
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