[HWYSTR455]

There were reportedly QA issues at the early release of the Sniper, and as I mentioned above, it's best not to buy bleeding edge stuff, give it a little time to 'bake'. 6 mo is a good 'bake time', all the initial run stuff has been hashed out and turned over, and you are in the mainstream of production.



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[HWYSTR455]

The latest revision of the Sniper uses a CAN connected hand held controller, and the software is pretty good. I would suggest at initial install, contact Holley support, and ask for firmware update recommendations.

Even if you have an earlier Sniper, or other Holley EFI product, I would suggest checking for updates at least annually. They do make improvements, ones that are worth updating for.

Here's the URL for the current list of firmware revisions:

https://documents.holley.com/techlib...2.19update.pdf

Keep in mind, you want to match the compatible versions of the hand held and the ECU when updating. Support will provide that info, but it is pretty safe to have the latest on both.

EDIT: Here is the top URL for all the tech docs and updates:

https://www.holley.com/support/fuel_...on/sniper_efi/


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[Firebob]

Yes, timing is controlled by the Sniper. I had forgotten that was an extra $400 for their dist. Supposedly it can be done with an HEI but while I was going through the process of discovery it was suggested ( by Holley of course) that all my issues would disappear if I was using their Dual Sync dist. At that point I was ready to try anything. Of course it made absolutely no difference but it is a nice piece so it stayed.

[Formulajones]

I've been doing a ton of reading and what's really bothering me about the sniper stealth is that you can buy the 4500 dominator series with 8 100 lbs. injectors and it supports 800-1500 HP NA, or 1250 with boost.

Yet you look at the 4150 series with the same 8 100 lbs. injectors and it only supports 650HP NA or 1250 boosted HP.

That makes no sense.
So the same fuel supply is there with the only change being a main body CFM difference, and we all know those 4150 bodies support more than 650 HP.

So why would the tech tell me I need an injector upgrade on the 4150 to support 750-ish HP??? The fuel is there, you can see that when compared to the 4500 series.

I'm thinking maybe they need to rewrite some of their literature.

[JLMounce]

It’s marketing pure and simple. They have overlapping products and want you to spend the money on the bigger one.

I will say that for a higher rpm big inch motor the throttle body of the basic sniper unit (including its carb look-a-like cousins) will become a limiting factor. They’ve been flow benched just north of 800cfm. If you’re making 700 hp at 6500 rpm on a 505” engine, that flow rate is going to be a hinderance before the injectors is.

The 4500 series units flow much better and are therefor better for big inch NA power.

[Formulajones]

Originally Posted by JLMounce

It’s marketing pure and simple. They have overlapping products and want you to spend the money on the bigger one.

I will say that for a higher rpm big inch motor the throttle body of the basic sniper unit (including its carb look-a-like cousins) will become a limiting factor. They’ve been flow benched just north of 800cfm. If you’re making 700 hp at 6500 rpm on a 505” engine, that flow rate is going to be a hinderance before the injectors is.

The 4500 series units flow much better and are therefor better for big inch NA power.

Thankfully I have that info since this engine has been dyno'd with both a dominator and the current 950hp holley. Ironically that 950 only flows about 870 cfm, yet the engine made 724 hp at 5700 rpm with it. So I'm pretty comfortable in my mind that the Sniper Stealth 4150 would support it, and likely flows better than the current holley carb considering there are no boosters in the way. But that's just me thinking out loud.

You may be right about the marketing ploy. Maybe that's why the holley tech didn't give me a complete answer on this subject. He did tell me the 4150 would support more HP with an injector upgrade, but he was referring to the 4 injector model. I have a sneaky suspicion that 4150 Sniper Stealth supports more than 650 HP with those 8 injectors, but it's not in the literature that way.

[Formulajones]

Just to add to make things even more confusing....

Looking over at Fitech simply for comparison sake, and they have an EFI 8 setup with 8 injectors (no mention of how big they are) But it's a 4150 size and supports up to 1200 HP and states it can be used on engines as low as 250 HP.

They also list another 4150 sized EFI also with 8 injectors that supports 800 HP. No mention of those injector sizes either but I'd suspect they are a pinch smaller.

So it would stand to reason the Holley Sniper Stealth 4150 with 8 100 lbs. injectors would do the same, even though the literature states 650 NA HP. It should work on lesser HP as well as support much more than 650 HP.

Am I missing something?

[Wick]

How does the system offered by Butler stack up? Anyone experience their system?

[JLMounce]

Originally Posted by Formulajones

Just to add to make things even more confusing....

Looking over at Fitech simply for comparison sake, and they have an EFI 8 setup with 8 injectors (no mention of how big they are) But it's a 4150 size and supports up to 1200 HP and states it can be used on engines as low as 250 HP.

They also list another 4150 sized EFI also with 8 injectors that supports 800 HP. No mention of those injector sizes either but I'd suspect they are a pinch smaller.

So it would stand to reason the Holley Sniper Stealth 4150 with 8 100 lbs. injectors would do the same, even though the literature states 650 NA HP. It should work on lesser HP as well as support much more than 650 HP.

Am I missing something?

The 1200PA uses 8 80lb injectors to achieve it's 1200hp rating. It can do that at 85% duty cycle on an NA application.

The reason the FiTech unit can also claim that it functions on engines making as low as 250hp is because it doesn't use all 8 injectors all of the time. It's firing only 4 injectors most of the time until TPS and MAP thresholds are met, then it fires the additional 4 injectors when demand requires it.

I haven't seen any information on how much the holley throttle body flows. Considering that FiTech held the patent for a self contained ecu on throttle body TBI system, it's probably very similar through a licensed process.

The FiTech systems flow about 830cfm out of the box. Several people have gotten those over 900cfm by placing a small radius on the bottom of the throttle bores, replacing the butterfly's with thinner units from a guick fuel carb, knife edging the throttle blade shaft and switching to countersunk mounting screws for the throttle blades.

the radius on the bottom of the bores can be done without disassembly and is reportedly worth about 20cfm.

[Formulajones]

Originally Posted by JLMounce

The 1200PA uses 8 80lb injectors to achieve it's 1200hp rating. It can do that at 85% duty cycle on an NA application.

The reason the FiTech unit can also claim that it functions on engines making as low as 250hp is because it doesn't use all 8 injectors all of the time. It's firing only 4 injectors most of the time until TPS and MAP thresholds are met, then it fires the additional 4 injectors when demand requires it.

And that's the interesting part. That's just simply a few settings in the software to accomplish that and would be very simple. So why doesn't Holley do that? Or does it?
With a program like that, I could run the Holley with 8 injectors on a 600 HP engine, and have room to grow into the 750HP engine I have planned at a later date, simply with tuning, and even have the option for a power adder on top of that if I choose. The 4150 with 8 100 lbs. injectors should easily support more than the 650 NA HP Holley has in their literature.

[JLMounce]

Not sure why Holley decided against that. It’s possible they had to materially change the throttle body compared to the FiTech unit to get around licensing costs with the patent.

That’s complete speculation of course. Easily as possible that it was just cheaper to use 4 larger injectors instead of 8.

It sounds like the FiTech 1200 PA is the unit you really need, but it doesn’t look like a carb. Is that your main sticking point?

[Formulajones]

Yeah looking like a carb is the sticking point. Dad is the same way so I blame him

I'm okay with just 4 injectors, they just need to be a pinch larger than 100 lbs. 120's would do it for the power level we want.

I really don't need the 8 injectors. I looked into the procharger deal pretty hard where that 8 injector unit would shine, but I just don't think I want a big intercooler on the car, hacking the core support, then likely having to do away with the fan shroud and clutch fan setup that works so well on the car, then it's electric fans and all that mess. So I'm going to bump the compression on the 502 with an overbore and piston change and go NA. The current 4 injector unit just doesn't supply enough fuel for what I'm doing. Would work nice on the current 454, but couldn't get the tech guy to elaborate on injector upgrades, cost, and difficulty. I'm of the understanding the unit has to go back to have that done. So I'm not really thrilled about that pathway and sounds like wasted money. I'd rather buy the unit with the injectors I need for the bigger build, and hope that it can tune itself and tame it enough to work on the current mill.

Dad however is in a different boat. His car is already making 724hp with a little 4150 carb, but they just don't make the 4150 stealth piece with the injectors to support it. Not in a 4 injector setup anyway.

What's odd, is they make the dominator 4500 with 8 100 lbs. injectors and they say that works fine on NA engines from 800HP up to 1500HP. I guess it's firing all 8 of those injectors all the time?? But the 4150 with 8 100 lbs. injectors are only firing 4 in NA mode, and can't bring in the other 4 as needed??

I guess you can see the gap that is creating and what is keeping me from buying one.

[HWYSTR455]

The 'regular' sniper stealth runs 4 100lbs injectors, x flow runs 4 120lbs injectors, and the super runs 8 100lbs injectors.

The super does batch fire across all 8 injectors. That's why it's not as granular. Plus there's the total CFM (of air) that has an impact, just like you wouldn't put a 1050cfm carb on a 6 cyl.

The FAST EZ-EFI 2.0 does batch in pairs, that's how it can do 250-1200hp. But I would suspect there will be a CFM flow issue over say, 900hp or so.

There's also the consideration of NA vs boosted, which skews the HP numbers. Or makes it more confusing, however you look at it.

Waiting for the intermediate Sniper Stealth offering isn't a bad approach. I would be a little gun-shy of having service replace the injectors in the existing stealth body. There's human error and QA factors involved.


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[Formulajones]

Originally Posted by HWYSTR455

The 'regular' sniper stealth runs 4 100lbs injectors, x flow runs 4 120lbs injectors, and the super runs 8 100lbs injectors.

The super does batch fire across all 8 injectors. That's why it's not as granular. Plus there's the total CFM (of air) that has an impact, just like you wouldn't put a 1050cfm carb on a 6 cyl.

The FAST EZ-EFI 2.0 does batch in pairs, that's how it can do 250-1200hp. But I would suspect there will be a CFM flow issue over say, 900hp or so.

There's also the consideration of NA vs boosted, which skews the HP numbers. Or makes it more confusing, however you look at it.

Waiting for the intermediate Sniper Stealth offering isn't a bad approach. I would be a little gun-shy of having service replace the injectors in the existing stealth body. There's human error and QA factors involved.


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Yeah, I'm pretty sure with the X-flow trying to fill that void, I won't have to wait too long before they also do the same with the Stealth setup. I think Holley is aware of the void with these systems just based off the way tech kind of bounced around my question.