When is PI needed?

[Tall Jim]

Originally Posted by Bluer2

Has anybody has found the limit of the stock injectors yet because the HPFP limit is reached first? In order to find the limit of the stock injectors somebody needs to upgrade the HPFP and to push those stock injectors to the limit so i think adding M5 injectors to upgraded HPFP will add more than 5-10% more fueling.

On E85 I've found that the injectors are what limits horsepower at higher engine speeds not the HPFPs. Above 5000 rpm I was severely limited by the injector and had to pull back torque to avoid leaning out. The HPFPs are only a limit at engine speeds below ~4500 rpm so if you interested in making a ton of torque between 3000-4500 rpm then upgraded pumps could be useful.

[Sejo5]

Originally Posted by TopJimmy

Thanks!

When you said "minus the pumps" do you mean you use the stock LPFP +PI and no problems fueling E85?

Hybrid turbos but not plus, right?

Are you 6MT or DCT?

Any dyno info?

Thanks again!

Sorry that i took awhile to answer - I am on Stock Pumps the difference according to my tuner was like +or - 30hp... before heading off to Engine Build territory. Pure Turbo Stage 2 High Flow. Its not the Plus which has the larger Compressor Wheel. Again Not needed unless ur looking to spend alot more money on New Clutches and Engine Build. I feel anything over 750+ is really pushing the stock rods and clutches so why spend the money on the Stage 2+ if your not really going to utilize it. Dont get me wrong i know guys who send the cars on stock rods and clutches and are fine.. but also ive seen guys send it on stock crankhubs lol. Only time can tell.

Im Dct stock Clutch. No Dyno. I have done 156 Trap at 1/3mile on pocono would have done more but my tire caught a leak. was getting faster with less fuel and higher e85 content. Im sure next event i will break 160+. 60 to 130 at 6.1 and that was on lower boost.

[Sejo5]

Originally Posted by NightF82

What kind of power did you end up making?

High 600 Low 700. Have a few revisions left on the table.

[Sejo5]

Originally Posted by E92TiAg335i

Do you run an intake or drop ins?

I run the Agency front Mount Intake.

[///BMW Junkie]

Can some explain how a PI kit on it's own without upgraded LPFP allows for more fueling to support full E on bigger turbos?

[TopJimmy]

Originally Posted by ///BMW Junkie

Can some explain how a PI kit on it's own without upgraded LPFP allows for more fueling to support full E(85) on bigger turbos?

Okay, you asked for it...

It doesn't...or the tune has been limited so you don't "lean out" and blow your motor.

Running full E85 Kill tune on stock turbos requires about 30% more fueling, and with upgraded turbos about 50% more (I figure).

Options are:
Do E50 with stock DI fueling, HPFPs maxed... Low risk, by failing a DI injector. Power is limited by DI fueling capacity.

Do E85 with stock DI fueling, HPFPs normal, and add only a PI spacer. Moderate-high risk, by error in your PI controller or PI injector clog (neither PI or DME knows, so boom), or LPFP can't keep up (DI can't compensate since PI still flows, so shutdown, maybe boom).

Do E85 with stock DI fueling, HPFPs normal, and add a PI spacer Piggyback LPFP and Hobbs. More wiring and/or plumbing depending on vendor. Moderate risk, like above without the LPFP risk.

Do E85 with M5 DI fueling, HPFPs normal, no PI or LPFP. Power limited like E50 up above, but E85 gives a little more torque. Custom tune required.

...then we get to M5 DI w/ Stg1 HPFPs no LPFP...and M5 DI w/ Stg1 HPFPs and LPFP and Hobbs...mitigating the risks of the PI controller/injector failure and the LPFP crash.

Steve from Fuel-It told me to add components in steps, and work with my tuner to watch HPFP/LPFP logs. Only do add-ons as needed to satisfy problems. He did not recommend for me to go balls out and buy everything. That's a good guy there, very helpful.

Now that I understand all-DI has much less risk than PI the consensus of gurus are to enhance your DI to M5 and add other parts only if needed for your built/tuned power level.

[///BMW Junkie]

Originally Posted by TopJimmy

Okay, you asked for it...

It doesn't...or the tune has been limited so you don't "lean out" and blow your motor.

Running full E85 Kill tune on stock turbos requires about 30% more fueling, and with upgraded turbos about 50% more (I figure).

Options are:
Do E50 with stock DI fueling, HPFPs maxed... Low risk, by failing a DI injector. Power is limited by DI fueling capacity.

Do E85 with stock DI fueling, HPFPs normal, and add only a PI spacer. Moderate-high risk, by error in your PI controller or PI injector clog (neither PI or DME knows, so boom), or LPFP can't keep up (DI can't compensate since PI still flows, so shutdown, maybe boom).

Do E85 with stock DI fueling, HPFPs normal, and add a PI spacer Piggyback LPFP and Hobbs. More wiring and/or plumbing depending on vendor. Moderate risk, like above without the LPFP risk.

Do E85 with M5 DI fueling, HPFPs normal, no PI or LPFP. Power limited like E50 up above, but E85 gives a little more torque. Custom tune required.

...then we get to M5 DI w/ Stg1 HPFPs no LPFP...and M5 DI w/ Stg1 HPFPs and LPFP and Hobbs...mitigating the risks of the PI controller/injector failure and the LPFP crash.

Steve from Fuel-It told me to add components in steps, and work with my tuner to watch HPFP/LPFP logs. Only do add-ons as needed to satisfy problems. He did not recommend for me to go balls out and buy everything. That's a good guy there, very helpful.

Now that I understand all-DI has much less risk than PI the consensus of gurus are to enhance your DI to M5 and add other parts only if needed for your built/tuned power level.

So why do some folks just go with PI kit alone if there's no improvement in fuel volume with stock lpfp? Is it a matter if bypassing the HPFP/injector bottleneck and lpfp is strong enough to provide extra fuel for PI to do its thing?

[TopJimmy]

Originally Posted by ///BMW Junkie

So why do some folks just go with PI kit alone if there's no improvement in fuel volume with stock lpfp? Is it a matter if bypassing the HPFP/injector bottleneck and lpfp is strong enough to provide extra fuel for PI to do its thing?

Correct. In the case you describe the PI is not running full-out and the LPFP can still keep up with demands. PI is still augmenting the DI fueling. A good tuner can see when LPFP starts to be affected and back the fueling down a little for pump longevity. If the owner still wanted more power then the LPFP would need an upgrade.

[olegalex78]

Originally Posted by TopJimmy

Okay, you asked for it...

It doesn't...or the tune has been limited so you don't "lean out" and blow your motor.

Running full E85 Kill tune on stock turbos requires about 30% more fueling, and with upgraded turbos about 50% more (I figure).

Options are:
Do E50 with stock DI fueling, HPFPs maxed... Low risk, by failing a DI injector. Power is limited by DI fueling capacity.

Do E85 with stock DI fueling, HPFPs normal, and add only a PI spacer. Moderate-high risk, by error in your PI controller or PI injector clog (neither PI or DME knows, so boom), or LPFP can't keep up (DI can't compensate since PI still flows, so shutdown, maybe boom).

Do E85 with stock DI fueling, HPFPs normal, and add a PI spacer Piggyback LPFP and Hobbs. More wiring and/or plumbing depending on vendor. Moderate risk, like above without the LPFP risk.

Do E85 with M5 DI fueling, HPFPs normal, no PI or LPFP. Power limited like E50 up above, but E85 gives a little more torque. Custom tune required.

...then we get to M5 DI w/ Stg1 HPFPs no LPFP...and M5 DI w/ Stg1 HPFPs and LPFP and Hobbs...mitigating the risks of the PI controller/injector failure and the LPFP crash.

Steve from Fuel-It told me to add components in steps, and work with my tuner to watch HPFP/LPFP logs. Only do add-ons as needed to satisfy problems. He did not recommend for me to go balls out and buy everything. That's a good guy there, very helpful.

Now that I understand all-DI has much less risk than PI the consensus of gurus are to enhance your DI to M5 and add other parts only if needed for your built/tuned power level.

Existing one more option, which we use on track cars.
Meth injection integrated in DME logic, with proper tune DME automatically
rise the boost/ignition/fuel calibration based on actual meth flow. So at the end you have bulletproof safe system.

[TopJimmy]

Originally Posted by olegalex78

Existing one more option, which we use on track cars.
Meth injection integrated in DME logic, with proper tune DME automatically
rise the boost/ignition/fuel calibration based on actual meth flow. So at the end you have bulletproof safe system.

Which controller and which tune platform for this setup...a Motiv Re|Flex into EcuTek?

If I ever did need Meth for power it would be sequential PI fired and CanBus connected like the Motiv. If just for cooling I'd use port nozzles and a simple setup. Good thing we can enhance our DI now so I can keep to one system and one fuel tank.

[dodospor]

how about running pi for meth , not e85 , anyone running this setup ? and is it better than 2 nozzle in chargepipe ?

[TopJimmy]

Originally Posted by dodospor

how about running pi for meth , not e85 , anyone running this setup ? and is it better than 2 nozzle in chargepipe ?

Port nozzle Meth beats CP bungs because of more even distribution across cylinders. PI Meth is preferred over any Nozzle Meth (port or CP bungs) because of more accurate metered delivery, and PI can be done in sequential fire instead of batch sprays. There is the higher cost of the advanced controllers available that tie back into the CanBus for messaging the DME. Most use the one-way batch fire method, and that SplitSec controller is less advanced, slower internally, and one-way communication (DME says to activate, but no feedback for error detection). If configured right Meth can be a strong power adder with low risk, but many just add it and hope for no problems.

[dodospor]

Originally Posted by TopJimmy

Port nozzle Meth beats CP bungs because of more even distribution across cylinders. PI Meth is preferred over any Nozzle Meth (port or CP bungs) because of more accurate metered delivery, and PI can be done in sequential fire instead of batch sprays. There is the higher cost of the advanced controllers available that tie back into the CanBus for messaging the DME. Most use the one-way batch fire method, and that SplitSec controller is less advanced, slower internally, and one-way communication (DME says to activate, but no feedback for error detection). If configured right Meth can be a strong power adder with low risk, but many just add it and hope for no problems.

thank you so much , i guess i will go with pi then

[olegalex78]

Originally Posted by TopJimmy

Which controller and which tune platform for this setup...a Motiv Re|Flex into EcuTek?

If I ever did need Meth for power it would be sequential PI fired and CanBus connected like the Motiv. If just for cooling I'd use port nozzles and a simple setup. Good thing we can enhance our DI now so I can keep to one system and one fuel tank.

We use EcuTek ProEcu for building software for and custom hardware, as i mentioned this give us fully integrated close loop setup, you cant make it with PI. If something will go wrong with any component, engine will run lean.