[LibertyHill]

With the limitations of fueling and spark advance due to compression, and the immense power down low in the powerband, would this make sense?

There isn't really much left past 6000 with this setup so why not remove 6000-6500 from the equation altogether and increase your reliability and safety margin? Or maybe even just 6200-6500?

Does HPTuners have this capability?

I tend to overthink everything having been without my car now for months...

[ADM PERFORMANCE]

Originally Posted by LibertyHill

With the limitations of fueling and spark advance due to compression, and the immense power down low in the powerband, would this make sense?

There isn't really much left past 6000 with this setup so why not remove 6000-6500 from the equation altogether and increase your reliability and safety margin? Or maybe even just 6200-6500?

Does HPTuners have this capability?

I tend to overthink everything having been without my car now for months...

It is still not done,Why?

[toohighpsi]

You kinda have to forget traditional thinking relating to fuel system and the LT1s. The fuel pump is now a positive displacement and fixed to engine speed (forget the in tank pump, it is simply a transfer pump and as long as it supplies some pressure to the main pump it is adequate).

Since our fuel system is now a positive displacement pump, and our engine is a positive displacement pump, they should be able to match each other very well - except for changes in VE (volumetric efficiency) - and that is where the problem lies. The fuel pump is moving a virtually incompressible fluid which provides a fairly linear delivery, the engine does not. The point of peak torque is also the point which requires the most fuel (highest pulswidth) for a given rpm so with a DI engine this becomes the limiting point of the fuel system. In reality at high RPM you normally have adequate fuel due to the lower VE of the engine, it's the peak torque points that test the limits of the fuel system.

[sub_ETCS_ret]

Originally Posted by ADM PERFORMANCE

It is still not done,Why?

What they^ said.

Sent from my SM-G920V using Tapatalk

[laynlo15]

What Mike said. You should listen, he knows his shit. By the way, nice ride Liberty hill

[LibertyHill]

Makes sense thanks Mike! Unfortunately my concern now revolves around the fact that the LT4 conversion makes that peak torque at a lower RPM where that PD fuel pump is not making maximum volume.

There were delays in getting several backordered parts from GM but its running now! Should be only a few more days...

[ADM PERFORMANCE]

Originally Posted by toohighpsi

You kinda have to forget traditional thinking relating to fuel system and the LT1s. The fuel pump is now a positive displacement and fixed to engine speed (forget the in tank pump, it is simply a transfer pump and as long as it supplies some pressure to the main pump it is adequate).

Since our fuel system is now a positive displacement pump, and our engine is a positive displacement pump, they should be able to match each other very well - except for changes in VE (volumetric efficiency) - and that is where the problem lies. The fuel pump is moving a virtually incompressible fluid which provides a fairly linear delivery, the engine does not. The point of peak torque is also the point which requires the most fuel (highest pulswidth) for a given rpm so with a DI engine this becomes the limiting point of the fuel system. In reality at high RPM you normally have adequate fuel due to the lower VE of the engine, it's the peak torque points that test the limits of the fuel system.

Exactly.I have concrete data of this actual problem.

[LibertyHill]

Originally Posted by ADM PERFORMANCE

Exactly.I have concrete data of this actual problem.

I guess that would explain the underdrive pulley?

[ADM PERFORMANCE]

Originally Posted by LibertyHill

I guess that would explain the underdrive pulley?

Yep

[ADM PERFORMANCE]

So I got a message today,Looks like the guys at Dedicated
Motorsports agree that this Lt4 Stuff has a place in the market

DAVE is a very good tuner and has a great reputation and group of guys working and building some incredible machines.

Hopefully we can assist if ever need be.

Btw-DAVE i has a whole shit load of takeout ls3 and Lsa injectors again ��

Cheers
Andy MAGES
Owner

[LibertyHill]

Great to hear thanks Andy! I can't wait to pick up the car and am very happy with the results.

The penny saving has already begun for stage 2!! Hopefully towards the end of the year.

[ADM PERFORMANCE]

Originally Posted by LibertyHill

Great to hear thanks Andy! I can't wait to pick up the car and am very happy with the results.

The penny saving has already begun for stage 2!! Hopefully towards the end of the year.

Good deal.

You will find that everything they are telling you about your car is true!!!!!!

A lot of fun, A lot of car at this power and torque level.

[wnta1ss]

Saw your dyno sheet with the LT4 blower installed LibertyHill, and the power peak is actually at a higher rpm than for the stock LT1 engine. Knowing this, I'd be inclined to raise the limiter a little bit, not lower it.

[LibertyHill]

Originally Posted by wnta1ss

Saw your dyno sheet with the LT4 blower installed LibertyHill, and the power peak is actually at a higher rpm than for the stock LT1 engine. Knowing this, I'd be inclined to raise the limiter a little bit, not lower it.

DMS is working within the limitations of stock fueling and the critical DI injector duty cycles, injection windows etc. so its at the safe limit right now.

I considered fueling upgrades but for the cost involved and the gains to be had it seems you approach the safe limits of the cast pistons pretty quickly. Makes more sense to me to wait a bit longer until I can afford internals as well, and maybe by then there will be a more cost-effective fueling upgrade available to take these well past 700WHP safely.