[Katech_Mike]

Originally Posted by Joshinator99

Agreed!



830 WHP corrected to STD is about 790-800 SAE which sounds about right for LT4 fueling. If you run 95 octane zero ethanol (or higher octane) you can stretch it further since it’s the E content that limits you on those injectors. I believe Vengeance did a bit over 900 STD with 95 octane zero ethanol by pushing the limit in terms of timing and fueling, but I seriously doubt they would have been willing to send that tune out the door to a customer.

I did the LPE high side (BB HPFP and LT4+52% injectors) with good results (906 SAE/942 STD) with plenty of wiggle room. The XDI stuff can stretch you a bit further since they add a second LT4 HPFP but I didn’t want to do that since my setup is simpler & cleaner. Port makes a bit less power than DI but the head room on a port system is pretty huge and likely a good amount less money (especially the toohighpsi setup). I wasn’t comfortable relying on meth at all, but to each their own.

We dyno everything in SAE. 830RWHP is about all the fuel system has on 93 using a 38% fuel lobe on our dyno.

We have made 870RWHP using XDI 30% injectors with a LT4 high side pump. At that point the high side pump is tapped.

I wouldn't recommend trying to run any mix of E at those power levels. There just isn't enough injector/pump to support it with OEM LT4 components.

The LPE pump is only about 10% better than the LT4 pump. If you're trying to run full E85 on DI only the XDI XFP system is currently the only option.

[KingLT1]

Originally Posted by Katech_Mike

We dyno everything in SAE. 830RWHP is about all the fuel system has on 93 using a 38% fuel lobe on our dyno.

We have made 870RWHP using XDI 30% injectors with a LT4 high side pump. At that point the high side pump is tapped.

I wouldn't recommend trying to run any mix of E at those power levels. There just isn't enough injector/pump to support it with OEM LT4 components.

The LPE pump is only about 10% better than the LT4 pump. If you're trying to run full E85 on DI only the XDI XFP system is currently the only option.

The LPE pump is only 10% better when driven by the same fuel lobe. However the LT4 pump can only handle up to a 38% lobe. The LPE gen 2 pump can run a 42 or 44% lobe(can't remember which off hand). So pair the LPE pump with the bigger lobe(GT35 cam with 7.85mm lobe for ex.) and it will go a bit further then the LT4 pump with 38% lobe.

[Smokin19]

Originally Posted by KingLT1

The LPE pump is only 10% better when driven by the same fuel lobe. However the LT4 pump can only handle up to a 38% lobe. The LPE gen 2 pump can run a 42 or 44% lobe(can't remember which off hand). So pair the LPE pump with the bigger lobe(GT35 cam with 7.85mm lobe for ex.) and it will go a bit further then the LT4 pump with 38% lobe.

Not trying to hijack a thread and very much a newbe to these LT4 engines and have a lot to learn. Saying that, I have a question about the the cam with a 38% lobe. I am planning a build with the 38% cam lobe. My build (app. 700-750 hp) will also include the Kong X port and simular to what the OP is doing. I am not chasing any number as this will be a build just for the street. My question is the durability / longevity of the high side pump using this cam lobe?

Another question, I will also be adding a low side pump but, don't like the idea of tapping into the fuel tank, is there an alternative?

[KingLT1]

Originally Posted by Smokin19

Not trying to hijack a thread and very much a newbe to these LT4 engines and have a lot to learn. Saying that, I have a question about the the cam with a 38% lobe. I am planning a build with the 38% cam lobe. My build (app. 700-750 hp) will also include the Kong X port and simular to what the OP is doing. I am not chasing any number as this will be a build just for the street. My question is the durability / longevity of the high side pump using this cam lobe?

Another question, I will also be adding a low side pump but, don't like the idea of tapping into the fuel tank, is there an alternative?

I have no idea on the longevity of the LT4 HPFP using a 38% lobe. Most that mod these engines that far do not seem to rack up a lot of miles and report back. I have heard through the grapevine that some shops report issues with a 38% lobe then others say it's fine.

Lingenfelter makes a drop in pump assembly that would give you more low side headroom. I do think it would work fine for many builds especially with a JMS hitting it with a few more volts when in boost. The Fore triple pump setup is the ultimate solution and is what LPE uses majority of the time on the 1000hp builds.

[GreenZLE]

Has anyone used a DeatchWerks 440 pump on the low side? Any real benefit above the factory pump?

[KingLT1]

Not sure...have heard some using a Hellcat pump as a upgrade.

[swisstyphoon]

Originally Posted by GreenZLE

Has anyone used a DeatchWerks 440 pump on the low side? Any real benefit above the factory pump?

Deatschwerks told me this week, that they are currently developing a dual in tank bucket kit for our cars.

[JSH]

I've referred to your corrected 830 wheel number here before as being close to what KaTech sees as the limit for the OEM high side on pump gas at lower elevations including your shop.

If I make 830 corrected wheel up here using a 20% correction it's like 700 measured HP up here, which means I can run some E85 to help make up part of the loss and ask more of my OEM pump/injectors. I don't yet know how much.

In this cool part of the year at your KaTech shop, how much of a CF on average would your dyno use, 3-5%?

Originally Posted by Katech_Mike

We dyno everything in SAE. 830RWHP is about all the fuel system has on 93 using a 38% fuel lobe on our dyno.

We have made 870RWHP using XDI 30% injectors with a LT4 high side pump. At that point the high side pump is tapped.

I wouldn't recommend trying to run any mix of E at those power levels. There just isn't enough injector/pump to support it with OEM LT4 components.

The LPE pump is only about 10% better than the LT4 pump. If you're trying to run full E85 on DI only the XDI XFP system is currently the only option.

[Joshinator99]

Originally Posted by GreenZLE

Has anyone used a DeatchWerks 440 pump on the low side? Any real benefit above the factory pump?

I tried a DW400 with a JMS voltage booster. I don't think it was worth the effort over a typical LT4 in-tank. I want to say around 800 WHP on 93 octane I was out of fuel on the low side yet again. I should have went right to the Fore setup when the LT4 wasn't cutting it... Oh well, my shop is getting really good at dropping my fuel tank these days.

[GreenZLE]

Originally Posted by Joshinator99

I tried a DW400 with a JMS voltage booster. I don't think it was worth the effort over a typical LT4 in-tank. I want to say around 800 WHP on 93 octane I was out of fuel on the low side yet again. I should have went right to the Fore setup when the LT4 wasn't cutting it... Oh well, my shop is getting really good at dropping my fuel tank these days.

I remember following your post and I was hopeful it would have worked out. Now that this 440 pump is out, I'd hoped it would make a swap worth while.


FYI, I picked up an extra in tank pump for $140 out the door so I'd have something on hand to mod when the time came.

[JSH]

Originally Posted by Smokin19

Not trying to hijack a thread and very much a newbe to these LT4 engines and have a lot to learn. Saying that, I have a question about the the cam with a 38% lobe. I am planning a build with the 38% cam lobe. My build (app. 700-750 hp) will also include the Kong X port and simular to what the OP is doing. I am not chasing any number as this will be a build just for the street. My question is the durability / longevity of the high side pump using this cam lobe?

Another question, I will also be adding a low side pump but, don't like the idea of tapping into the fuel tank, is there an alternative?

The due diligence I've done so far on making say 750-800 wheel actual/uncorrected with a new high side pump and injectors leaves me with these:

LPE's Big Bore high side ($1735) https://www.lingenfelter.com/product...l#.YWm7cRrMJMs

XDI 30% injectors ($2500)
https://shop.katechengines.com/produ...-injectors-30/

DI (LPE $6400) seems to be the next step up.

Really no choice on the high side but numerous choices on injectors. KingLT1 has recommended FIC +30's.
Basically all I've done is confirm what others have said here previously.

[Choda]

Is the general rule for upgrading injectors once you hit the 6ms threshold?

[KingLT1]

Originally Posted by Choda

Is the general rule for upgrading injectors once you hit the 6ms threshold?

Depends on your SOI table. If it's adjusted to start injecting fuel as early as possible then you can get away with higher pulse widths. I believe the caveat is that it costs a little combustion efficiency but allows us to get more fuel in the chamber without spraying it out the exhaust causing a false rich condition. In a perfect world we don't do much with SOI and have enough fuel to keep injectors down around 5ms or less.