Holley Sniper EFI

Started by MiniDave, August 28, 2020, 08:42:56 PM

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Over the last few days I cut the adaptor plate out for the single bbl EFI unit to fit the Nikki manifold. I sent the manifold off to a machinist friend who reset the mounting studs to fit the 2bbl EFI unit so I had to modify the mounting holes I'd already drilled to fit the original Nikki spacing to fit the single bbl unit to the manifold. My plan is to run the single on the test stand first to figure out how to make it all work, then put the 2 bbl unit on my 1275 motor in my Racing Green car to  see how it all works in an actual car, since I can't put any load on the motor in the engine stand so the unit can "learn" a run map.

So I now have both the single and 2 bbl units fit to the manifold so I can switch them out easily. My machinist buddy also has the maps saved in his mill so he can cut spacer plates out of aluminum or phenolic material for me, as well as convert the manifold stud spacing easily. He also matched the opening in the Nikki to the bores of the 2bbl.

All of this is just preliminary to actually fitting it to an engine and a car. An SPi manifold can be made to work with a little bit of surgery here and there, but the Nikki is even easier and it fits better. I was able to lop off a water jacket boss on the bottom of the SPi manifold and now it will work with either exhaust header too.

So, single bbl units for the small engines - 998 and 1098, 2 bbl unit for the "big" motors is the plan - Holley says the single can support up to 200 hp but I dunno, it doesn't seem like it could flow enough to really build some HP in a 1275 or 1380 motor with a nicely flowed cylinder head.

My buddy forgot to cut the phenolic spacer for the 2bbl unit - it's only needed to provide clearance for some of the linkage and other bits - who knows maybe it's a good idea to have it for heat insulation too? If so, i can make one for the single bbl version too, there's plenty of room between the top to add an air cleaner too so, another 1/4 or 3/8" of height won't matter.

At this point both projects are on hold for a while. I have a car coming in the shop the 26th for a suspension overhaul and an engine being delivered around Nov 1 that will need to be torn down and parts sent off to the machine shop, and I'm back working on the Inno to get it up and running. I'm down to a short amount of time before I'm laid up in January with my knee replacement. I'm still only able to work a little here and there, but I'm determined to get these projects finished.

The EFI project will have to wait.

Linkage on the single bbl is going to be interesting, and I may have to build some brackets and such to get it to work - no real idea how to do that yet,  I tried the single bbl on both ways as it will fit either direction and it looks like having the linkage off the back of the manifold will work the best but I won't know for sure till I try it in a car - and right vs left drive may make a difference too. The 2bbl unit will only fit one way, so I'll just have to engineer for that mounting position. I'm excited to see it run and work, but I have to finish the other commitments I made first.
Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad


For keeping with that orientation, we'll need to either find a supply of the Nikki manifolds or find someone to duplicate them.

Do you have a regular SU/HIF manifold to try for the other orientation?

How are each of the units on the Nikki manifold for having bonnet clearance with an air filter attached?


Bonnet clearance with the Nikki should be fine with either single or 2 bbl. won't know for absolute sure till I try it, but based on the height compared to the normal SU, shouldn't be an issue.

I have SU manifolds and will try the side draft orientation too at some point. I also have made up an adaptor to mount  the single bbl to a standard 998 cast intake/exhaust manifold to see if I can make that work too, but the two bbl won't work with any side draft manifolds that I know of....short of welding something up .....and I'm not going there as long as there are other choices.

The 2bbl won't work with an SPi manifold either....so it's really down to the Nikki for them right now.

The weber manifold would have needed an adaptor to make it work with either unit, but I played with it again and I still can't make it work with either header, so unless someone needs it for a Sprite, it's going back.

Complete failure at retirement

1989 Cooper Racing Green
2009 Clubman S
2014 Audi Allroad


It's too bad with all this covid non-sense. Sounds like a great time for a "garage day" or 2 to smash out some work on things before you have to go down for a while. I'd love to learn more about the engine/trans building process, which I can obviously do on my own, but it's a whole lot more fun learning from someone with a lot more knowledge and the learning curve moves a lot faster.

Maybe things will get back to some sort of "normal" one of these days LOL.