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Has anybody switched from carb to the Holley Snipper efi, if you have what kind of results have you seen?

This gets kicked around every few months and I’ve yet to hear of any solid results either way regarding aftermarket TBI systems. MPI systems seem to be a winner. On the BBC forums on cars the Sniper gets rave reviews, but in a Marine application where the engine spends most of its life near redline the throttle body seems to be a restriction. Autos spend .001% of their life near redline so they’d never notice. That’s my internet education on the matter.

I have a buddy who converted to snipers on 540s on a big 40-foot cruiser. Loves em!!! no worries with hudreds of hours.

Quote:

Originally Posted by Swamplizard (Post 4649530)

I have a buddy who converted to snipers on 540s on a big 40-foot cruiser. Loves em!!! no worries with hudreds of hours.

That seems like a great application for them. Do you know if he ran closed loop or locked in the tune?

He actually had them installed locally and they got tuned at the dock (he had wifi) by a guy in Canada - then I believe he removed O2 sensors after the tune.

I’ve had my eye on sniper for a while. They make 2 versions, a 4150 style good to approx 600 Hp and a newer 4500 version good from 800 to 1200 Hp. My problem is I’m in between the 2. It sounds like a esources lower HP version of the 4500 is in the works of which I’m very interested. The sniper concept in general looks very good and I believe Holley by far has the resources to get it right and stand behind it. Very interested in input from others. I think the fuel system make over is the biggest challenge as you need to run a return line.

As an alternative I’m looking at diving into my carb to see how close I can get it and considering the K&N electronic fuel injection (assist) that works in conjunction with a carburetor. It’s half the price and doesn’t require a new fuel system. If I can get the carburetor close and just need a little help trimming the fuel curve it might be just the trick.

Quote:

Originally Posted by ezrizer (Post 4649699)

That’s pretty much the same situation I’m in. I’m curious which route you’ll go. I like the K&N idea of not having to reinvent the plumbing but the price point puts it near the base price of a full system. Although just as some people are still attached to carbs I feel the same way about mechanical fuel pumps, and a decent electric pump is ~$500

I'm being dragged kicking and screaming into the EFI age, but to be honest, I've had super luck with Holley's on a boat, as long as it's naturally aspirated or roots blower. If you have a carb system, there's quite a bit of money involved in changing the fuel system on top of the injection cost. As boats aren't generally aren't about super accurate throttle response, and gas mileage, really? Mine, you pump once, hit the key and it explodes! Both engines. Ran perfect for years, year in and year out. If I were rebuilding back to what it was, I'd go carbs.

However, I'm going turbos, and the setups I bought require injection, so I'm stuck. I think it depends on what you feel comfortable with. I grew up with Holleys, so they are in my 'comfort zone'. EFI, I'm learning! LOL!

I spoke with K&N today and their ECi doesn't seem practical for my application. As others have pointed out at $800 you're well on your way to fuel injection so why not keep going. I thought with ECI you'd tune your carb lean and let the ECI trim the fuel curve as needed to maintain AFR but that's not what K&N said. In fact they didn't recommend having it active or in service continuously, rather occasional only when the 02 sensor detected a lean condition. It doesn't have an IAC so it's not going to be very helpful if RPM is to low in gear (my problem). I like what CDShack said and I'm inclined to get my carbs calibrated accordingly and i think I'll be fine. I've had a number of carbureted that ran fine, Just not one with this much cam and this much prop but as I said I'm hopeful with the right calibration things will work out.

I'm taking it in steps:

Adding bigger oil coolers and heat exchangers
Fresh fuel pumps (mechanical) and 1/2 hoses all the way
Adding Weiand 177 blowers with pre-configured Holley carbs
Adding O2 sensors to Gils and AFR guages so I can see where Air to fuel ratios are on carbs.....
Then, eventually, going with the Snipers

We will see how it works out for big cruiser.