JHM Stage 1 HPFP question

[wootwoot]

I currently have an APR HPFP and am running JHM stage 1 on 91 octane. I'd like to switch back to my stock HPFP. Will the JHM tune adapt on its own if I swap back to the stock HPFP or will I need to do something extra to prevent possible issues?

[derrek]

I currently have an APR HPFP and am running JHM stage 1 on 91 octane. I'd like to switch back to my stock HPFP. Will the JHM tune adapt on its own if I swap back to the stock HPFP or will I need to do something extra to prevent possible issues?

why do you want to switch back to stock?

[SamsonKnight]

So he could help this fellow ziner(me) build his stage 3 bt setup. Isn't that right @wootwoot!?

[onedumslack]

You should not need to do anything. Jhm stage 1 91 Oct does not require an upgraded pump. But yeah, why would you put it back to stock?

[Jake@JHM]

You should not need to do anything. Jhm stage 1 91 Oct does not require an upgraded pump. But yeah, why would you put it back to stock?

Yeah, the only thing that will change is the duty cycle on your solenoid. Looking to upgrade to the JHM HPFP?

[B7OrangeA4]

Theres also 91 stage 2 that doesnt require fuel pump i believe but im having blast with the upgraded pump. Just need trans tune and stage 3 ::drool::

[Jake@JHM]

Theres also 91 stage 2 that doesnt require fuel pump i believe but im having blast with the upgraded pump. Just need trans tune and stage 3 ::drool::

Check your email/PM!

[XanRa]

Just need trans tune and stage 3 ::drool::

I agree

Haven't heard anything about that teams tune in a while...

[martin0079]

Yeah, the only thing that will change is the duty cycle on your solenoid. Looking to upgrade to the JHM HPFP?

Not an upgrade when going from an APR pump I am afraid.

[ericpaulyoung]

You definitely should have the r^2 and displacement in the tune match the pump. CAN you run an upgraded pump without changing the tune. YES. Should you, NO. But since you are on a tune that doesn't require it, your engine will run more "proper" by taking it out.

EPY

[Jake@JHM]

Not an upgrade when going from an APR pump I am afraid.

How so? APRs piston size is 9.5 while ours is 9.8, therefore our pump will move more fuel and lower the solenoid duty cycle even further.

[martin0079]

How so? APRs piston size is 9.5 while ours is 9.8, therefore our pump will move more fuel and lower the solenoid duty cycle even further.

Your pump does not address upgrading the seal APR, IE, and HPFPupgrade all address it. Sometimes it isn't always about who has the bigger erm stick. In this instance the smaller stick wins because they put on a condom and didn't have a kid. An audiziner awhile back had his OEM seal fail on the KMD HPFP kit which is similar to yours no seal upgrage and dump gas into the crankcase.

[Jake@JHM]

Your pump does not address upgrading the seal APR, IE, and HPFPupgrade all address it. Sometimes it isn't always about who has the bigger erm stick. In this instance the smaller stick wins because they put on a condom and didn't have a kid. An audiziner awhile back had his OEM seal fail on the KMD HPFP kit which is similar to yours no seal upgrage and dump gas into the crankcase.

I can see where you are coming form.

Fortunately for us and everyone, this is an extremely rare occurrence. Otherwise people left and right will be having these failures even on bone stock cars.

We also have the option of a brand new pump with our internals should a customer have a bad OEM pump, they can get a whole new one including a brand new seal.

[martin0079]

I can see where you are coming form.

Fortunately for us and everyone, this is an extremely rare occurrence. Otherwise people left and right will be having these failures even on bone stock cars.

We also have the option of a brand new pump with our internals should a customer have a bad OEM pump, they can get a whole new one including a brand new seal.

This will not happen on a stock car there is no step piston on a stock car.

SEE:

[vce1232000]

This will not happen on a stock car there is no step piston on a stock car.

.....

Why doesnt JHM just that situation by addressing the possible seal failure. It had happened to other companies. So it can happened to JHM Upgraded internals also

[wootwoot]

So he could help this fellow ziner(me) build his stage 3 bt setup. Isn't that right @wootwoot!?

This.


My old tune took advantage of the upgraded HPFP but with JHM there is no need to use an upgraded pump.

[ktish]

This will not happen on a stock car there is no step piston on a stock car.

SEE:

Please explain to everyone why the step piston is such a terrible design? I'm not seeing it when you're talking about precision machined pieces.

[aluthman]

Your pump does not address upgrading the seal APR, IE, and HPFPupgrade all address it. Sometimes it isn't always about who has the bigger erm stick. In this instance the smaller stick wins because they put on a condom and didn't have a kid. An audiziner awhile back had his OEM seal fail on the KMD HPFP kit which is similar to yours no seal upgrage and dump gas into the crankcase.

I thought KMD products were pretty much regarded as being junk? Seems like an unfair comparison. That being said, I have an HPFPupgrade pump so I have no dog in this fight.

[AudiTunes]

Could you go JHM Stage 2 with just an upgraded HPFP? Or do you need the exhaust upgrade?


Also how different is Stage 1 from Stage 2?

[derrek]

Could you go JHM Stage 2 with just an upgraded HPFP? Or do you need the exhaust upgrade?


Also how different is Stage 1 from Stage 2?

its one more

[martin0079]

Please explain to everyone why the step piston is such a terrible design? I'm not seeing it when you're talking about precision machined pieces.

Yay JHM Nut swinging. It is probably the fact that fuel goes under the step and then is pounded into the seal by the step. I never said the step was a poor design just that not upgrading the seal was bad. If you notice 1 of the companies I listed uses a step design. Also read this from IE:

Consistent diameter piston
With rigorous testing behind this product, we have determined that a consistent diameter piston is absolutely necessary. Many other upgrade kits available use a piston that steps down to smaller diameter. They do this because it allows them to use the original seal and nut assembly. However, doing this means that less than 1/2 of the cylinder is guiding the pin at the top of the stroke. This greatly increases wear, leakage past the pin, and decreases stability of the pin riding in the cylinder. Additionally, using a stepped cylinder causes a pumping action on the bottom side of the piston, which pulses fluid against the shaft seal, increasing the possibility for leakage into the cam follower region. With our consistent diameter piston, as with factory design, there is no displacement change occurring on the bottom side of the piston, so there are no pressure pulses against the shaft seal.

I thought KMD products were pretty much regarded as being junk? Seems like an unfair comparison. That being said, I have an HPFPupgrade pump so I have no dog in this fight.

I ran one for a long time without issue. I eventually upgraded to the HPFPupgrade one for fear of my seal giving out. I did this before IE came out with theirs. If I had to choose now it would be IE all the way.

[ktish]

Thanks for the explanation, all about that learning

[vce1232000]

I thought KMD products were pretty much regarded as being junk?

Their 1st generation HPFP upgrade internals was the tty quality. Since then they are using a different company with different materials and coatings. I was considering a few companies when my HPFP took a . But decided to use APR HPFP again since it was no fault of the pump but my own carelessness