Sniper 2GC EFI swap (1 Viewer)

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jmcclusk

SILVER Star
Joined
Oct 22, 2011
Threads
13
Messages
183
Location
Portland OR
Lots of Sniper builds, but haven't seen many 2GC large bore snipers so here is what I did. Advantage of the 2GC is it looks better than the 2300 in this situation and it fits directly to the stock air cleaner assembly. I designed and machined an adapter between the manifold and 2GC. I still used the carb insulator to try to keep the heat down. Used a RobbMc performance powersurge pump being fed by stock pump. Stock air cleaner assembly. AN braided lines. Stock distributor, but basic recurve springs installed.

Still tinkering with the settings and tuning, could use some pointers for what people did for timing. Manual says 7°, but some other posts say more like 12°. Seems to run better at 12 to 14, what have you done here?

Also, the Sniper AIC seems to be a little slow to react. The feedback loop is slow enough it revs up over the target rpm and then dumps back down 100 under and keeps surging gently like that. If you stick your finger in the sniper and plug the AIC passage while its running it flattens out perfectly smooth... If I bring the idle screw in so it is idling above the target idle the AIC goes to 0 understandably and it smooths out, but if you screw it out so the AIC is anywhere positive it surges up and down. I have checked for an air leak, but none found. What do other people do here?

Have other people got better gas mileage with snipers? it doesn't seem to help mine, but I'm still tuning it...

thanks,
John

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You won’t get better gas mileage by going to efi in fact it might be slightly worse. Unless you specifically tune fore fuel mileage at the cost of everything else
 
It looks super sanitary. You are probably going to need to dink with the AIC a few times before you find a happy place. It's imperative that you have even vacuum and your valves are adjusted properly to get a good tune. It seems that if all is perfect with your engine and fuel delivery and return, it's still necessary to fine tune from a laptop to prevent stalling on a cool motor during down shifting.

Timing is a whole can of worms because desmogging. You don't want to exceed 28.5° total advance but that doesn't mean you can run that much because of the advance curve. I'm having pretty good performance using the HEI and I believe I'm set at 11° static.
 
Nice job. I’ve installed 5 2GC large bore but all of them have been on FJ40s.

Mosley Motors sells the adapters that I used. Yours looks sweet. Nice work.

My latest.

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Looks great. How did you mount the surge tank?
thanks! I mounted it to the firewall kinda nestled under the wiper motor and between the AC lines/washer fluid tank. its pretty close, but worked out fine. I put a small block under the lower screws because the firewall isnt flat there, top screw was on a protrusion.
Do you have a cap on the 3/8” bung in the center front of the 2GC?

Sure sounds like a vacuum leak with the surge.

Did you follow the IAC initial setup in the manual?
I have a cap on the vac nipple on the side nearest the firewall, and am using the vac nipple on the radiator side for the distributor advance. Not sure if these are the ones you mean, I don't see any others. I agree it is acting like a vacuum leak, I can't find one though. Yeah I did the IAC initial setup in the manual. Your setups look gorgeous!

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Update on the 2GC Large Bore Sniper, the initial idle surging problems were simply solved by messing with the mixture tuning for awhile. In case it helps someone else in the future; I had the mixture for idle set up too lean, thinking 14.7 being stoichiometrically 14.7 ideal but it actually likes being down richer at like 12.7 to 13.

It works great and no problems for the last year and a half and several thousand miles. The best part of this is starting it, I can start it when its cold outside by just putting it in neutral and turning the key. I've even cold started it while standing outside and ice scraper in my other hand. As it warms up it idles down by itself and no more vapor lock when hot and stopping at a gas station in the heat. Still the old truck feel and sound, but now with the new truck starting and consistency. I also passed a DEQ test in Oregon with it, though it took some messing with the mixture and timing a bit, but these were easy with the Sniper settings. Not saying it would fly in California, they actually look for all the original equipment there.

The 2GC Large Bore fits to the stock air cleaner directly up at the right height, just takes changing the center screw thread to be the M6 of the wingnut. All the tapped holes I did with helicoils to be more durable than just aluminum threads as the wear surface of screws being installed/removed over the years.

I had 8 of these 2GC Large Bore adapters made because I didn't see anything I could buy except the 2300 adapters and didn't like that look or design to the air cleaner. I am using one so have 7 left. There was someone else on mud working on a 3d printed version, and I 3d printed my own with high temp filament / CF filament / oven bake filament / all different fill % and they all failed on the engine. they softened and relaxed under the bolt wide washers but they all started leaking air. not worth your time. Maybe a resin type might work, but in my opinion it isn't worth the effort, aluminum works great, its just tough doing the overhang of the machining.

If anyone wants one of these adapters, let me know, I'm thinking $300 since I did all the work and its a single piece with overhang and helicoils. Redline is selling theirs for $305 now FYI.

Happy to answer questions. Cheers, John

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