Xtreme HPFP

[Blackjack]

I've decided on installing an Xtreme HPFP-45 direct injection fuel pump to my 2020 GT with Whipple Stage 2. Anyone have any experience with adding this pump with an aftermarket tune? I'll likely go with Lund or PBD. I know you can get all the fuel you need from the port injectors, but increasing fuel flow on the DI side seems to make more power, and is a way more efficient burn based on research I've done. Any input from those "in the know" is appreciated.

Sponsored

 

[illtal]

I've decided on installing an Xtreme HPFP-45 direct injection fuel pump to my 2020 GT with Whipple Stage 2. Anyone have any experience with adding this pump with an aftermarket tune? I'll likely go with Lund or PBD. I know you can get all the fuel you need from the port injectors, but increasing fuel flow on the DI side seems to make more power, and is a way more efficient burn based on research I've done. Any input from those "in the know" is appreciated.

Si senor, keeping the GDI blend high does help with detonation prevention, and thus giving you more from octane limited fuel (which is why you can run 87 octane in your mustang). I would ask your tuner of choice have do they work with that pump and do they tune for it before you install it.

But honestly there may be other ways to get the same results via a cheaper method. I don't recall hearing anyone on here actually running one on a GT when I asked about them a few years ago. But maybe things have progressed enough and the pumps are cheap enough to be a viable option now.

Edit
https://www.mustang6g.com/forums/threads/xtreme-di-hpfp45-direct-injection-pump.131199/

 

[engineermike]

I’ve done quite a bit of research and modeling on this and will be ordering one when they go on sale.

Basically the stock pump isn’t sized for much more than 460 hp. Stock runs 90% gdi and 10% pfi. When you add boost you can no longer run 90% gdi because the pump can’t keep up. I have tweaked my cal and was able to get it to run 80% gdi at low rpm but it quickly tapers down to 65% by midrange. Many aftermarket FI cals will just run it at 60% and call it a day. So not only are you adding cylinder pressure and heat, but you’re taking away your detonation suppressant. Keep in mind also when checking hpfp duty cycle that you have to account the coldest possible air and cat protect. I shoot for around 75% max duty cycle in typical conditions for this reason.

If you study the injector timing you see that the gdi injection is done almost entirely on the intake stroke. Academic studies have shown that the detonation suppression works better if you inject on the compression stroke. I tried this. It didn’t work. I later realized that I was trying to achieve stratified charge and the mustang 5.0 pistons aren’t shaped correctly for that. However, increasing the size of the hpfp will allow injection to extend further into the compression stroke before running out of fuel pump, so the benefits should compound.

All in all, keep in mind that you’re not going from 0% to 100% gdi so you won’t be able to add 4 psi boost or 4 deg timing. The gains will be smaller than this. However, if your intent is to maximize power on a knock-limited fuel, this is one option to get there.

 

[illtal]

I’ve done quite a bit of research and modeling on this and will be ordering one when they go on sale.

Basically the stock pump isn’t sized for much more than 460 hp. Stock runs 90% gdi and 10% pfi. When you add boost you can no longer run 90% gdi because the pump can’t keep up. I have tweaked my cal and was able to get it to run 80% gdi at low rpm but it quickly tapers down to 65% by midrange. Many aftermarket FI cals will just run it at 60% and call it a day. So not only are you adding cylinder pressure and heat, but you’re taking away your detonation suppressant. Keep in mind also when checking hpfp duty cycle that you have to account the coldest possible air and cat protect. I shoot for around 75% max duty cycle in typical conditions for this reason.

If you study the injector timing you see that the gdi injection is done almost entirely on the intake stroke. Academic studies have shown that the detonation suppression works better if you inject on the compression stroke. I tried this. It didn’t work. I later realized that I was trying to achieve stratified charge and the mustang 5.0 pistons aren’t shaped correctly for that. However, increasing the size of the hpfp will allow injection to extend further into the compression stroke before running out of fuel pump, so the benefits should compound.

All in all, keep in mind that you’re not going from 0% to 100% gdi so you won’t be able to add 4 psi boost or 4 deg timing. The gains will be smaller than this. However, if your intent is to maximize power on a knock-limited fuel, this is one option to get there.

In your opinion, does the gen 3 need both the pump and larger DI injectors? Or is the 45% extra fuel pressure enough to overcome the midrange drop in blend?

I believe that I was told to really make it work right that the injectors are needed to be able to go up to 90% blend or more on boosted applications which would add like 1700 more dollars.

 

[engineermike]

I’m going to try it with just the pump. If my math is correct it will be able to maintain 85+% blend on a stage 2 Whipple with enough overhead to handle cat protect mode and cold ambient. At my current 65% there is lots of injection window left so I don’t see it running out of time. Even if it does there is more room to raise gdi pressure.

 

[Blackjack]

If detonation is the primary concern behind DI, then this may not be money well spent for me. I always cut 91 (CA) with 100 race gas. Math says I’m running 95.5 at that ratio. The tune is for 93, so I have a little over head.

interestingly, Lund has just replied to me saying I don’t “need” the XDI. No one needs go fast parts, but we dang sure WANT them! I’m sure I don’t, but I’m wondering if this is because they don’t have a tune for it, or if the higher octane I’m running makes it not worth it? I know PBD did some tuning for Hellion with this pump, so I’ll see what they have to say about it.

Mike - If you are after the HPDI-45, 5 Star Tuning has it for $1,599 and they have 5% discount right now. I don’t know if they mispriced it or what because it’s $2,500 everywhere else.

 

[engineermike]

@Blackjack detonation prevention is almost entirely THE reason that GDI exists. If you aren’t up against a detonation limit, then it’s probably not money well spent. With port injection most of the cooling of fuel vaporization is applied to the valve and port material. With GDI, most of the cooling effect is applied to the air.

I saw that on 5 stars site and it almost certainly is a misprint. There is a smaller 5.0 pump that sells for about that price. Lethal will be putting xdi on sale for 10% off soon.

 

[illtal]

@Blackjack detonation prevention is almost entirely THE reason that GDI exists. If you aren’t up against a detonation limit, then it’s probably not money well spent. With port injection most of the cooling of fuel vaporization is applied to the valve and port material. With GDI, most of the cooling effect is applied to the air.

I saw that on 5 stars site and it almost certainly is a misprint. There is a smaller 5.0 pump that sells for about that price. Lethal will be putting xdi on sale for 10% off soon.

I'd say methanol/water (or straight water since he's mixing 100 octane) injection can give cylinder cooling and the added benefit of lowering IATs, thus more power due to a denser air charge. For the OP this may be a double benefit to him due to to the fact if he runs out of 100 he can go to a 50/50 methanol/water.

It will take hundreds maybe thousands of gallons of meth, to get to 2500 usd.

Sponsored