Holley Sniper XFlow announced

The Sniper that has been out for a couple of years only is good up to 650 hp. We've tested them on 700+ hp engines and they work, but they do kill a bit of power. There wasn't a good solution for guys with 700+ hp engines but now Holley has introduced a new version of the Sniper with a larger throttle body and larger injectors. This one is supposed to be good for 800+ hp. I have one on order and will get pictures of it on the dyno once I get the test scheduled. We have a 700+ hp BB Mopar with Trick Flow 270 heads that has been looking for a solution. The owner wants EFI but none of the existing single throttle body kits could support the power.

https://www.holley.com/products/fue..._tbi_kits/sniper_efi_xflow/parts/550-541

I look forward to your review of it! 👍

I don't understand why they go to the trouble of giving the entries the nice radiused profile, but use a small 1.69" throttle plate with half-round shafts and big, obstructive, throttle-plate screws that choke the airflow.

Brad, I'll let you know how it works on a 700+ hp Mopar big block. This unit should be exactly what you need on your car.

I recently put a super sniper on my sb 70’ Duster. So far I’ve been real impressed. It’ll be getting a turbo this winter. Kinda wish the xflow deal was available then but oh well.

How do the new EFI setups handle "big" cams and the inconsistent idle vacuum & jacked-up AFRs that come with high overlap & reversion? That seems to be one of the first things some carb gurus point to when asked to compare FI with carbs.

From what I've seen so far it is easier to tune a big cam with fuel injection than with a carb. On key is to have the ignition timing controlled by the EFI system. If you can control both the ignition and the fuel with the laptop then you can usually dial the tune is really quickly. Basically you just keep throwing ignition advance at it until the engine starts to behave and then you twist the knob on the fuel to see what the engine likes. It also helps to start off with a high idle speed and then as you get the tune dialed in you can drop the speed down to a point where the noise is tolerable for street driving. Once you get it stable at idle in neutral and in gear then you can work on off idle and transition tuning.

Rich is the best guy to talk to about tuning with big cams. He has probably done more than 1000 race car EFI tunes. He does a couple of tunes a day so he has seen it all. I've watched him tune a few engines and if there aren't any mechanical problems he can do the tune in just a few minutes. Sometimes we run into hidden mechanical problems which really slow down the process but if everything is working properly it is a very fast process.

That's good to hear. The Sniper my son bought said it was good for like 600 or so N/A hp and for 1200 hp boosted I believe. Course we plan to supercharge his and are hoping to be in the 800 to 900 hp range when we get it tuned in with the supercharger on it later. Ron

Wilson 4150 TB

That is nice!

nice. Have to tell us how much difference from the standard Sniper.
When I installed the FiTech 1200PA, I figured the smaller Throttle body might cost some power, but the driveability is so much better that I didn't mind as I don't go to the track that often.

Everyone told my son and I he will slow down a tad with EFI. He did not care because we will be supercharging the car later and we wanted it to be EFI for when we supercharge it. So we put it on now to get the EFI dialed in and get it working good so when we supercharge it we wont have to start from scratch with the EFI. Of course we know we will have to change the tune from N/A to supercharged. And he has slowed down a bit as he ran 11.40's on good days with the 750 DP and on an average day he ran 11.60's so far with the EFI. But as said we are not worried since its getting a huffer soon.

But like you he loves the driveability of the EFI and says he don't care if its a tad slower because he likes the EFI better for all around driveability. Ron

My Xflow showed up today. Should have it on the dyno in a couple of weeks.

Ran it on the 505 today. Made good power and pulled hard to 6500 rpm which is all the further we wanted to spin this engine. The engine makes right at 700 hp for long stretch at the top end so it should go down the track pretty nice. This is a pump gas setup with a Comp street roller and Trick Flow 270 heads.

Can't seem to find a solid answer about E-85 compatibility. Can you use it? Do you have to lie to the handheld to compensate for the fuel? I can't believe they would build something like this without bringing the cheap octane of E-85 into the plan/discussion. This sounds like the answer to my problems, a unit big enough to get the job done.

The instructions say unleaded fuel only. You can run E85 if you want but the Sniper isn't designed for it so there is a good chance you'll run into some sort of problem.

How did the power compare to the same motor on a carburetor?

I am running the Sniper Stealth 4500 on my Hemi......I like it a lot...