[Stefano]

Originally Posted by wnta1ss

Mr Jannetty said that the lash cap he used on the gray car was only to make up for the reduced base circle of the +32 fuel lobe on the aftermarket camshaft.

He is correct regarding the smaller base circle used in order to get the increased 32% fuel lobe lift and the cam to pass through the journals.

There are several fuel lobe profiles available. We did and still do have concerns regarding the longevity of the 32% lobe increase on the stock pumps, so this is something to keep an eye on.

A lash cap is necessary in order to pick up the gap, when a smaller base circle is incorporated. (We have used a 14% fuel pump lobe with no lash cap.)

I believe these diaphragm high side fuel pumps, produce linear pressure and while we haven't tested a lash cap on a stock LT1 pump (Note: LT4s have a slightly longer plunger.) I do not see how starting the plunger out higher but keeping the stoke the same will increase the pressure?

https://issuu.com/cpg-development/docs/cpg5-2014/3

[LesBaer]

Originally Posted by ProCharger

After watching plenty of people for the past couple years knock their HPFP's right off the engine block...
My best advice is talk to your cam provider to see what they want you to do with the HPFP.
Since not all lobes are the same...

Otherwise you could end up with the "rattle rattle, thunder clatter, boom boom boom" ....
The sounds of the HPFP bottoming out, and eating itself alive.
(Personally have never used a "lash cap" nor had a reason to.)


For "normal" street cars making less then 800 rwhp with boost.
The simple combo is just a nice cam (with extra lobe)
And voltage booster for the LPFP. (plus a touch of meth)
That combo will allow you to make MORE power then a stock LT can handle.

A local shop here in KC (House of Boost) has been cranking out 750+ rwhp combos week in and week out like that, using the following combo.

HOB 2016 Camaro F/I Cam (no cap, stock HPFP)
ProCharger P1SC System
Snow Meth System

Simple, Proven, "Bang for the Buck" Combo that = Fast Camaros. (and vettes)


Otherwise you are talking spending MAJOR money on the fuel system, for the same results.
Fuel Pump Swap for LP side. (or booster, or aux pump)
LT4 Pump Swap for HP side
LT4 Injectors

Not saying thats "bad"...but thats a LOT of coin to get the same results.
Since at the end of the day you are trying to get a LOAD of fuel into the cly in a small injection window.
(Plus D/I really isn't that fantastic at WOT anyways, hence why you see Ford swapping to a blend of D/I and Port Injection in 2018)

Pay a little more now, or pay a lot more later I guess.

[EDFHOBBIES]

Originally Posted by toohighpsi

I can't see what a lash cap does on a stock system unless there is some amount of lost motion within the cam follower. With a smaller base circle cam it's completely understandable.

With a completely stock LT1 fuel system the most I was able to make was ~620 RWHP. It's important to note that I'm running at standard conditions on most days. I'm at 100 ft above sea level with a temp normally right about 65F, so there isn't really much of any dyno correction - the car is making the power that the dyno displays. When testing at higher altitudes you could get a higher RWHP number on stock parts but that would be because of the correction factor that is applied by the dyno to the data.

I'm now running the stock LT1 injectors in the Camaro with the Lingenfelter Big Bore HPDI fuel pump to the tune of 690 RWHP which is the point where the low pressure system was down to under 30PSI (didn't run out of fuel, but wasn't comfortable to go further). We are switching to the ZL1 in-tank pump right now and I'll get back on the dyno to see if the stock LT1 injectors will go 700 RWHP with the help of the ZL1 in tank and Lingenfelter big bore pump.

Now in my mind, I have a tough time recommending the LT4 pump, on my Z06 with TVS 2300 the LT4 fuel pump lost capacity at just over 650 RWHP (I thought that 700 would be in reach). With the cost of the LT4 pump at about $800 it seems like the best choice is to go right for the Lingenfelter Big Bore pump along with LT4 injectors as the injectors still had capacity left when the LT4 HPDI pump gave up the ghost. I'm thinking there is 750 RWHP capability with Big Bore pump and LT4 injectors on an otherwise stock engine (good fuel of course).

Lingenfelter has a really big set of injectors that they recently released, capable of over 1K HP if I remember correctly.

I am working on additional fueling for the Camaro beyond that point and will be happy to share as soon as I have some performance data on it.

the injectors are like 500ea, and the pump is 1500 eat my wallet away!

Someone has got to do something!

[Stefano]

More lash cap info:

How the lash cap is installed is also important as it will technically fit both ways, however only one way is correct. The lash cap should be installed on top of the lifter which pushes up towards the sky (cap goes down towards the floor) and the fuel pump plunger will sit down on top of it.

This will fill the gap .059 -.060 created by the smaller base circle of the cam fuel pump lobe. If the cap is placed on to the bottom of the pump the lash cap will not properly seat and will take up more space and add preload.

The lash cap being installed upside down might cause the travel to max out and potentially crack the valley pan and/or pump flange.

[Stefano]

Lash Cap pictures.

[ProCharger]

Originally Posted by Stefano

There are several fuel lobe profiles available. We did and still do have concerns regarding the longevity of the 32% lobe increase on the stock pumps, so this is something to keep an eye on.

These have been used for going on years now, with no issues.
So one would have to think its "good" at this point.
Honestly, I think I tuned one of the very first units that left comp...
Still running like a top to this day.

Personally, I have seen more failures of OEM pumps, on brand new cars.
Than anything involving an aftermarket cam at this point.
(Obviously disregarding people that bugger up their install)

If I bought a new LT motor'ed car/truck today.
I wouldn't hesitate in the slightest to install a cam with the higher lobe,
And drive it every single day, and rely on it as a daily driver.

[ProCharger]

Originally Posted by LesBaer

Pay a little more now, or pay a lot more later I guess.

A lot later for what?

Originally Posted by EDFHOBBIES

the injectors are like 500ea, and the pump is 1500 eat my wallet away!

Someone has got to do something!

Won't happen, for many reasons.

[toohighpsi]

Originally Posted by EDFHOBBIES

the injectors are like 500ea, and the pump is 1500 eat my wallet away!

Someone has got to do something!

LT4 injectors are like $60 each, but yes the Big Bore pump is $1500. That combination will take you pretty far.

[LesBaer]

And then more money to put that power to the ground.

[PRAY]

Great discussion guys. So if I am tracking, lash cap with 32% fuel lobe. Boost a pump for the stock in tank pump and you could hit 700rw? Then add some meth to go beyond that? I am going to be doing head/cam soon in preparation for my blower conversion. I don't like to rely on meth for a fuel source, only for cooling and equaling out winter and summer power. What are the limitations of just 93 octane for Prochargers approach to fueling? I am sure I will do a ZL1 pump eventually. After that I assume it is LT4 injectors before the LT4 HPFP? I am sure I will be out of blower at my next round of mods. I am only looking to make 650-700rw tops.

[JANNETTYRACING]

Originally Posted by PRAY

Great discussion guys. So if I am tracking, lash cap with 32% fuel lobe. Boost a pump for the stock in tank pump and you could hit 700rw? Then add some meth to go beyond that? I am going to be doing head/cam soon in preparation for my blower conversion. I don't like to rely on meth for a fuel source, only for cooling and equaling out winter and summer power. What are the limitations of just 93 octane for Prochargers approach to fueling? I am sure I will do a ZL1 pump eventually. After that I assume it is LT4 injectors before the LT4 HPFP? I am sure I will be out of blower at my next round of mods. I am only looking to make 650-700rw tops.

I am sorry I don't see the LT1 pump and LT-injectors with a 32% lobe supplying enough fuel for 700 RWHP.

Ted.

[PRAY]

Before this thread I had not heard they would either. That is why I am trying to get some clarification on what was stated by Procharger.

BTW, I need to call you about your smooth idle blower cam or a variation there of.

[JANNETTYRACING]

Originally Posted by PRAY

Before this thread I had not heard they would either. That is why I am trying to get some clarification on what was stated by Procharger.

BTW, I need to call you about your smooth idle blower cam or a variation there of.

I am at my desk

[toohighpsi]

Originally Posted by LesBaer

And then more money to put that power to the ground.

Traction not a problem Les