My GPRXP build

[John's truck]

If you have a local battery store that sells lots of powersports size batteries they probably have some of those non-captive nuts laying around loose, left over or fallen out from other new or dead/old/returned/warranty batteries.

Bring in the remaining square nut as a sample.

I would imagine they would just give you a few.

I thought about it today, but the Nearest one is a bit of a drive. The ones I ordered should be here tomorrow though. It’s just weird... Tractor supply was the only store that actually had the lawn/motorsports batteries but no luck there either. These stupid things fall out all the time but nobody seems to sell them. Guess I’ll just have to keep a bag of the spares.

Fuel system wise, I realize I no longer have a filter after the pump. I may add one in closer to the fuel rail. Just an in line AN filter or something. But I may wait until I get a new fuel rail and switch the fuel system around to a flow-through instead of dead-head.

[K447]

… These stupid things fall out all the time …

Squirt a dob of silicone or similar underneath the nut with the bolt snugged (no cable yet). Let it set, then each nut should stay put when the bolt is removed. You can do this with a new battery before you put it into the hull.

As an alternative you can inject hot-melt glue under the nut in the same manner. Just make sure the bolt is fully inserted beforehand so there is room for the thread length when you are later attaching the cable to the battery.


One of the reasons I like the Deka ETX series AGM battery is that there is no loose nut, the bolts thread right into the post.

Odyssey brand powersports batteries also have no loose nuts, bolt threads right into the post top.

[John's truck]

Well the battery nuts I ordered got delayed. So I took a regular hex nut, filed it down and then dropped it in the hull . So I took another, filed it down, and hooked the battery up. Put on the DESS, listened to the pump take prime and then saw a nice big leak on the 90 leaving the sender. The swivel seal on the AN 90 let go. So I just ordered a 2 pack and should have them this week. I need to blow out the cooling system tomorrow or the day after. We have a freeze coming this week.

[John's truck]

Well these stupid things showed up. I am going to glue/silicone them in to the battery posts. But, now I'm waiting on a 90 degree AN6 fuel fitting before I can try to fire it back up.

On the plus side, when I did put the key on, I heard the fuel pump catch prime really quick and pushed fuel. Downside was it leaked. But my electrical work- worked.

[John's truck]

Well I winterized the ski today. We’re supposed to have a freeze tonight and then a couple nights next week. When the fuel fittings show up I can hook up the fuel system, test that, maybe start the ski to idle it and then shut it down and fog the cylinders and pull the battery out for the winter.

[John's truck]

Well the AN6 90's I ordered showed up, so I went over to the storage and installed, hooked up the battery, and tried to fire the ski up. I kinda forgot I put oil in the cylinders and had left the water box disconnected. So antifreeze kinda went a lot of places. Anyways I hooked it all back up, started it and revved it. Talk about a smoke screen. Anyways the fuel pressure holds damn solid at 58-59. So I ÔÇ£couldÔÇØ go ride the ski just like this and test to make sure AFR's are good. But it's cold out now. And I'm putting the factory ECU up for sale so if anyone wants to buy it, message me. Daddy wants a Fueltech FT450 for Xmas

[John's truck]

Well I'm not making much progress on the ski, so I decided to redo my degree wheel. This time I downloaded a better template and engraved it out of brass sheet. I need to drill and bolt it to the clamp.

[John's truck]

Finished. Now I have a degree wheel I can clamp on to the midshaft

[smokeysevin]

Finished. Now I have a degree wheel I can clamp on to the midshaft

That turned out great, nice work

Sean

[John's truck]

That turned out great, nice work

Sean

Thanks. Im sure the plastic one would have done the job OK but it was a little… lame. I need to pull the battery out of the ski to put it on a tender, So when I go over there I’ll figure out what I’m doing for a needle/mark on the ski side. The midshaft bearing housing has a threaded hole up top so it might just be a simple metal arrow. And I guess I need a spark plug extended wire, oh and a crank lock tool to set for setting TDC

[John's truck]

So I just ordered some goodies. Everything I’ve read on GreenHulk says the RXPX 255 ECU (which I’m using) is mapped right so with 48 or 50 lb injectors and rising rate fuel pressure, it will be pretty spot-on for a ET137 wheel. So… I just bought a cheap 137 wheel, used stock 48 lb injectors and EV6 to EV1 injector connectors. I understand there are differences in injector dead times going from the Bosch Green giant 42’s to whatever the stock 48’s from the Bosch ECU skis are. I know it won’t be perfect and I’ll still be limited by the stock rev limit and timing. Which means the Yamaha boat prop is probably going back on, and we’ll see if we can get it up to 8000 rpm. I need to track down my extra McMastercarr spring washers to bring slip up to 15 lb, and I need to set up the fuel pressure for rising rate. I really didn’t want to run the Rochester/Riva 50 lb injectors I have now since they’re notorious for locking up at like 62 psi and I’m planning on base pressure of 58+ 13 to 15 psi on top. That’s danger zone for the 50’s. I think the 48’s will be fine.

And, if this setup pisses me off too much, I’ll go to a stand alone and just tune the damn thing for real, raise the rev limit to 9000 and spin the Dynafly as high as it wants to go. I was already planning on running this same supercharger and boost referenced fuel pressure to keep a 58 psi differential across the injectors. So this won’t be unneeded steps. I’ll keep using this stuff in the future. Maybe with different injectors but that’s easy enough to swap out.

Also, I am already monitoring AFR’s, just checking them visually as I ride. I can’t log them.

[John's truck]

Little more on that. I bought a used fuel rail with injectors. It's from a 2012 GTX 215, but the injectors are the same as the RXPX 260. They're the Deka long tip 8 hole 48's which I guess all iControl skis used. Since they're used, I'm going to need to flush and Test them. I'm thinking I have an easy solution. They're already mounted in fuel rail. I can just fill the rail and inlet hose with WD40 or PB blaster or something, pressurize the hose with 60 psi air pressure, and then give each injector 12v so it sprays in to a bucket. I'll run a good amount through it and then move to the next one. Obviously this won't be a scientific test, but it should show if they're clogged/leaking/dripping and show spray pattern.

Kinda ironic though. Siemens ECU skis used Bosch injectors. Bosch ECU skis used Siemens (Deka) injectors. What's Next, dogs playing with cats?

[John's truck]

So the next think I need to address is the boost reference hose. I know that Rising rate used to be common in the tuning world you get increased fuel pressure up top and better idle. But then it fell out of favor once large injectors with short minimum on time came on scene and ECU’s could idle them without having to reduce fuel pressure. Rising rate was viewed as an old school way of maxing out injectors by cranking up fuel pressure.

But there’s still the other aspect of it. A boost reference fuel pressure system maintains the set pressure differential across the injectors. There will be 58 psi across the injector under vacuum, cruising, and at WOT. At 15 psi of supercharger boost, I won’t have 58 psi fuel minus 15 psi in the manifold so 43 psi differential and now the injector flow rate is reduced significantly.

But anyways, I need to decide where to drill for the boost reference hose. I’m using an older throttle body without the fogging nipple. And I don’t really like the idea of drilling the intake manifold barbs for the line. I did that for the boost gauge and I don’t like it. So I’ll probably drill and tap the front circular plate on the manifold to 1/8 NPT and use push-lock fittings for nylon tubing.

[John's truck]

Well I just ordered 10 feet of poly pneumatic 1/4” tubing, and a pair of 1/4 push lock 1/8 NPT fittings. So I’ll put one on the FPR and one in the manifold like this:

[beerdart]

1/4"OD may not signal well I went with 5/32" and it worked well. I can supply you with some.

Well I just ordered 10 feet of poly pneumatic 1/4” tubing, and a pair of 1/4 push lock 1/8 NPT fittings. So I’ll put one on the FPR and one in the manifold like this: