[Becker]

I've been running the KB 2.8L on my stock 6.1 Charger for about a year now and I'm unclear on the fuel pressure I should be seeng at WOT under boost. I'm using the Zeitronix ZT-2 to monitor fuel pressure and I'm seeing less than 60psi (low to mid 50psi) at WOT. What pressures should I be seeing if my BAP is working correctly?

 

[BB2010SRT8]

I would think no less than 58 psi.


Sent from my iPhone using Tapatalk

 

[check6x]

The title got my interest! How in hell is he running on 8 pounds of fuel pressure.

My Mercury outboard wants a minimum of 51 pounds, I rigged a water pressure gauge to read it.

 

[Sjohalsrt8]

The title got my interest! How in hell is he running on 8 pounds of fuel pressure.

My Mercury outboard wants a minimum of 51 pounds, I rigged a water pressure gauge to read it.

He Is running 8psi of boost and seeing under 60psi fuel.

 

[silverbulletSRT-8]

The pressure in the manifold will cancel out the incoming fuel pressure, so if you were running 60psi at the rail, and then boosted it to 10psi, your injectors would only really be spraying at 50psi

 

[JonW]

The pressure in the manifold will cancel out the incoming fuel pressure, so if you were running 60psi at the rail, and then boosted it to 10psi, your injectors would only really be spraying at 50psi

To state this another way...

Stock pressure is 58 PSI. If you're boosting 8 PSI, your rail pressure should be a minimum of 66 PSI (only at the point in time when you are at 8 PSI of boost though). That's the job of the BAP - to boost the fuel pressure in relation to the manifold pressure so that your net fuel delivery is always equivalent to the unboosted pressure.

 

[Becker]

To state this another way...

Stock pressure is 58 PSI. If you're boosting 8 PSI, your rail pressure should be a minimum of 66 PSI (only at the point in time when you are at 8 PSI of boost though). That's the job of the BAP - to boost the fuel pressure in relation to the manifold pressure so that your net fuel delivery is always equivalent to the unboosted pressure.

So, if my BAP is working correctly I should see fuel pressures greater than 58psi at WOT instead of lower?

 

[Becker]

The title got my interest! How in hell is he running on 8 pounds of fuel pressure.

My Mercury outboard wants a minimum of 51 pounds, I rigged a water pressure gauge to read it.

He Is running 8psi of boost and seeing under 60psi fuel.

Thank you for clearing that up for him.

 

[JonW]

So, if my BAP is working correctly I should see fuel pressures greater than 58psi at WOT instead of lower?

Correct. Maybe a dumb question, but is your BAP attached to a vacuum (boost) line? It also may not be adjusted properly.

 

[Becker]

Correct. Maybe a dumb question, but is your BAP attached to a vacuum (boost) line? It also may not be adjusted properly.

Yes the BAP switch it is attached to a vacuum boost line.

 

[SamySnead]

Have you thought of ditching that BAP and going with the Arrington dual pump setup? HEMI Dual Fuel Hat
BAP are nothing but problems in my opinion and just shorten the lifespan of the fuel pump. It was a "nice" idea when we didnt have pump upgrades, but now I think its silly to use them.

BTW, article on fuel pressure since there seems to be alot of confusion: Injector Dynamics - Fuel Pressure Article

 

[Becker]

Anyone from Kenne Bell out there? Mike? Matt?

 

[[email protected]]

To state this another way...

Stock pressure is 58 PSI. If you're boosting 8 PSI, your rail pressure should be a minimum of 66 PSI (only at the point in time when you are at 8 PSI of boost though). That's the job of the BAP - to boost the fuel pressure in relation to the manifold pressure so that your net fuel delivery is always equivalent to the unboosted pressure.

Wrong. Pressure is regulated in the tank with a relief valve which "pops off" at 60 psi. Engine HP and Fuel pressure is tuned by Kenne Bell for 8 psi. Delta pressure of injectors is considered. Higher boost requires re-tuning as the Dodge is speed density.

 

[[email protected]]

Have you thought of ditching that BAP and going with the Arrington dual pump setup? HEMI Dual Fuel Hat
BAP are nothing but problems in my opinion and just shorten the lifespan of the fuel pump. It was a "nice" idea when we didnt have pump upgrades, but now I think its silly to use them.

BTW, article on fuel pressure since there seems to be alot of confusion: Injector Dynamics - Fuel Pressure Article

No, your BAP is working. Again, the fuel pressure is controlled by the relief valve in the pump assembly. The BAP controls fuel FLOW. The additional flow supplied by the BAP prevents the PRESSURE from falling below 58 psi ( ALTHOUGH YOU CAN SEE A SLIGHT PSI DROP AT THE RAIL AT WOT). The BAP pressure switch activates the BAP only when the engine is in boost.
We have no record of an actual BAP failure in the last 6 years. MILLIONS OF MILES, NO FAILURES. It is used on all KB kits. The concept is now also used by our competition on their kits. It is very reliable. And the BAP on a Dodge will support up to 775RWHP. That's 400HP over stock.
We have our own Dual Pump System designed but +775RWHP applications are rare so the sales picture isn't all that attractive. Also, multiple pump systems are VERY expensive, they heat the fuel, require re-tuning, rewiring and re-plumbing to a return style system. The only application we recommend dual pumps for is the +775RWHP. As the old saying goes "If it ain't broke, don't fix it."

 

[magmax06]

when the BAP was not installed on my car and the supercharger was on, I was reading 55 PSI, ( i run the 392 Pump)
After the KB BAP install, I now have a 60 PSI constant in all condition, even if I turn it to the max, I cannot go over 60 PSI !

 

[Becker]

Thanks guys. No worries then.

 

[Hemi31]

Wrong. Pressure is regulated in the tank with a relief valve which "pops off" at 60 psi. Engine HP and Fuel pressure is tuned by Kenne Bell for 8 psi. Delta pressure of injectors is considered. Higher boost requires re-tuning as the Dodge is speed density.

God I love the Kenne Bell attitude.....lmfao. I think it's even funnier that you just told off one of the most knowlegeable people in the injector industry.....smooth.....lmfao.

 

[SamySnead]

No, your BAP is working. Again, the fuel pressure is controlled by the relief valve in the pump assembly. The BAP controls fuel FLOW. The additional flow supplied by the BAP prevents the PRESSURE from falling below 58 psi ( ALTHOUGH YOU CAN SEE A SLIGHT PSI DROP AT THE RAIL AT WOT). The BAP pressure switch activates the BAP only when the engine is in boost.
We have no record of an actual BAP failure in the last 6 years. MILLIONS OF MILES, NO FAILURES. It is used on all KB kits. The concept is now also used by our competition on their kits. It is very reliable. And the BAP on a Dodge will support up to 775RWHP. That's 400HP over stock.
We have our own Dual Pump System designed but +775RWHP applications are rare so the sales picture isn't all that attractive. Also, multiple pump systems are VERY expensive, they heat the fuel, require re-tuning, rewiring and re-plumbing to a return style system. The only application we recommend dual pumps for is the +775RWHP. As the old saying goes "If it ain't broke, don't fix it."

No one ever said anything about a BAP failing. Obviously you didnt read what I wrote. However, Ive personally run into failures of stock fuel pumps because the simple fact that electric motors are only designed to operate in specific ranges. Adding a BAP is fine, but nothing good can come of adding more and more voltage and overspinning a motor. But thats just my opinion and Im sure you have yours as well.

And multiple pump systems arent "VERY" expensive/etc. What does the Arrington 255 add-on setup cost, $150 more than a BAP? Wow...and I dont think its more wiring than a BAP as well.

 

[Becker]

Thank you Matt at KB, I respect your knowledge on the KB BAP topic.

Is anyone running a stock KB setup with a fuel pressure gauge that actually sees fuel pressure psi's higher than say, 62 psi?

 

[Hemi31]

You won't see higher pressure because like Matt said it's regulated in the tank. The BAP is there to maintain the 58 psi at the rail,also like Matt said. However , JonW was dead on about the boost knocking back the fuel that actually sprays out of the injector. So even at optimum pressure at the rail you will suffer fuel pressure loss at the injector which makes it more critical your fuel system is working right. You need to make sure the BAP is working right...or better yet a pump thats actually capable of delivering the right pressure without a BAP.