Challenger 4tec Upgrade

[Sportster-2001-951C-Stock]

I dunno what's going on with this exhaust exactly so forgive my misunderstanding but after exiting the waterbox it seems like you could use PVC pipe and rubber exhaust hose (maybe even formed automotive radiator hose?). As long as there's cooling water......... I've used sections of cast iron pipe combined with marine exhaust hose for mercruiser exhaust setups many times, looks good painted black. A bud used PVC for his "beer budget mercruiser build" and once he corrected the(incorrect) cooling issue the schedule 80 PVC was holding up behind that small block (Even with good cooling small blocks make tons of exhaust heat WOT ya know, so I didn't really trust his PVC setup).

Or, might be able to get a muffler shop to bend up some stainless exhaust pipe into a reasonable configuration?

 

[alexd51]

I"m actually going to do all the welding myself. My dad and uncle welded up a little sail boat in their basement

They have some equipment and expertise to draw from. I plan to weld a custom fuel tank for my boat. I'm shooting to get at least 35gal out of it. Not sure if I'm going to weld up a metal exhaust or just use rubber pipes. I love the noodle mock up idea though. I will probably use that, thanks for the tip :thumbsup:

And how are they going to get it out of the basement???? or they just planing to flood the basement and leave it there? lmao

 

[IDoSeaDoo]

And how are they going to get it out of the basement???? or they just planing to flood the basement and leave it there? lmao

LOL I asked them the very same question the first day they told me about it. There is a large window in the basement. They measured it and are confident that, once removed, the boat will fit through the window opening. The boat doesn't weigh much, I'm guessing 400lbs. 3-4 people can probably just pick it up and walk it out.

 

[IDoSeaDoo]

Been soooo busy with Life-stuff... now going away for a business trip for 4 days. I can't wait to resume progress on this next week. The weather is getting nice, and I'm getting real antsy to get this baby on the water!!

 

[1983]

Yooo, let me know next week when you are working on this..I'll ride over from Raleigh to take a peek. Maybe [MENTION=59515]suke[/MENTION] wants to meetup too.

Rob

 

[IDoSeaDoo]

Yea man, I'll hit you guys up.

 

[1983]

Cool


Rob

Yea man, I'll hit you guys up.

 

[suke]

Yooo, let me know next week when you are working on this..I'll ride over from Raleigh to take a peek. Maybe [MENTION=59515]suke[/MENTION] wants to meetup too.

Rob

I'm in. Just not Tues nights, I have soccer those nights. I live close to Andrew anywho.

 

[1983]

Coo, need to plan a good outing/meetup at lake also




Rob

 

[IDoSeaDoo]

Yea, if I join, it'd be with my old GTS. The SPX shit a crank last season. Probably as a result of my cylinder cooling drain line being totally clogged. Probably been like that for years... My dilemma is which to fix first, the boat, or the ski. The ski would probably take less time, but I really hate to start a new project before finishing the current one. If I were you (if you own a 787), I'd check that drain line coming off the rear of the cylinders, going to the exhaust. You'll have to pull the Batt. and yank it off the exhaust outlet.

 

[IDoSeaDoo]

Hey guys, need your input here. I'm in the process of modifying my water box. I need to shorten it, and I'm realizing that the bottom baffle is in the way. What are the effects and restrictions of modifying this baffle? I need to cut it back about an inch or two to keep the same size opening as before. I don't want to stifle the engine but neither do I want a loud engine... what to do?

I couldn't upload a pic, but my earlier post has a pretty good shot of the water box and baffle

 

[rjcress]

Hey Sportster, how far from Smith Mountain Lake are you? I think it's only about 4hours from me. I've been meaning to go. When I get this baby running, we should go cruising out there

Holy shit! I was getting WAY too sucked in to SeaDoo stuff last year and forced myself to stay off of the forum over the fall and winter. I have to say... you are one crazy bastard.
I think that is why we have always gotten along well on the forum.
I thought you were nuts to take this project on, but you appear to be proving me wrong.
Let me know when you guys head to SML. I keep the Challenger there all summer and my big boat. I'm up there most weekends when it is warm enough.

 

[IDoSeaDoo]

Haha thanks. Yea, it is an ambitious, but not as bad as the one before that. Doing boats is way more fun than fixing hail damage and painting a car in the winter lol. Busy getting married these days, no time to work on the boat. Soon though...

 

[IDoSeaDoo]

Ughhh it breaks my heart to see these little challengers zipping around the lake out there. I CAN'T WAIT to get mine finished and take it out. Haven't had time to do ANYTHING on her lately. It's jet ski season and I'm busy getting a sea-worthy seadoo ready for my honeymoon to Florida. Ocod, want to cruise the Miami harbor again soon? :cheers:

 

[MPower]

Have you sorted the exhaust yet? If not, have you looked at using the setup from the 2008+ 4TECs where they got rid of the J pipe? It's a much more compact setup.

http://partsfinder.onlinemicrofiche... AMERICA (DAYGLOW YELLOW) [21CA] EXHAUST ASSY.

 

[IDoSeaDoo]

Oh man, that's awesome! I wonder if it's any more silent... i really want this thing to be quiet. Man, the prices here are prohibitively high. Unfortunately, I'm operating on a budget and already have all the original pieces, but this would certainly make it cleaner with one less pipe going across the pump tunnel. I'll poke around ebay, see if anyone is selling these things cheap.

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[MPower]

I doubt you will notice any big difference in sound level in the newer setup. I also usually remove the silencers from my 4TECs because I love the sound.

You should be able to source a 08+ waterbox setup fairly cheap and it is soooo much better than the J-Pipe setup.

 

[IDoSeaDoo]

Man, that setup does look much better. Seems like it would flow so much better. There are a lot less turns, however, all these components appear very hard to find, and are very expensive when I do come across them. Not having an entire setup to plunder from also can leave me with missing parts and the need to fabricate/improvise. I think if anything, I'd like to just get the second muffler to replace the secondary I have from the 03 GTX. The original forces me to come out and jump back across the pump tunnel and exit on the port side. With this updated one, I can pipe directly out the starboard side. The only issue with that is there is already an exhaust outlet of just the right diameter on the port side where the original exhaust exited. I don't like making new holes, but at the same time, it would make the job look so much cleaner inside...

Getting new resonator
Pros: cleaner setup, less piping, easier plumbing with one less jump over the pump tunnel, probably lighter overall weight

Cons: must drill new exit hole on starboard side, must fill existing hole on port side, must bear the cost of the new muffler, also the extra piping of the original setup would probably make for quieter engine operation

Decisions decisions....

 

[MPower]

Dual exhaust

 

[IDoSeaDoo]

Lol too many holes in the boat. I'm infected with the idea of this exhaust system. It does make more sense, and if i ever decide to upgrade later, the exhaust is already good to go. I realized that I did glass in a mount for the old style waterbox already.... maybe the new one will fit on its place. I found everything but the rubber connectors on ebay for about 300. I also sent an email to Tonka to see if he has the setup and what he charges. I can't tell my wife if I do end up getting it, our budget is tight as piano wire...

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[IDoSeaDoo]

So I bought that exhaust system, but again, it's too big... Having already glassed in the support and mount for the original exhaust system that I already hacked up to fit, I'm hesitant to cut into yet another. Also, I'm not sure that the fiberglass mount I fabricated will work with this setup, as the angles are different.

I also started in earnest the daunting task of building the fuel tank. I used 3d modeling software to design it. It's a very complex shape, as I have to indent it to make room for the longer engine, as well as increase it's former (inadequate) capacity. I'm sorry, but 28 gallons was just NO ENOUGH. Before, I was constantly checking my fuel gauge, and always finding it much lower than I had hoped. I know how hungry of a beast this 4tec is. That 16 gal would barely last me half a day. This being a boat, I will definitely be spending entire weekends on the lake. So capacity is what I'm going for.

I am currently building the tank out of OSB, to see how and IF if will fit. Here's the model I'm building from:

This design should hold about 35.6 gallons, the weight of which should be ~224lbs (only ~45 more than original).

I had to make an indentation in the top because of the tall fuel pres reg. Almost did away with the original fpr and went aftermarket. But in the end, it was cheaper and easier to just put give up a little volume.

One thing I wonder: At full tank, would there be any effects to the pressure regulator discharging excess fuel while it's submerged 2" below the fuel line... I think it might increase the fuel pressure in teh line, but not enough to notice. The spec is 42 +/- 5psi so I think I'll be okay.

 

[IDoSeaDoo]

Well, it was a damn good idea to make the model. I would have never gotten the tank in had I built it to that plan. The new one is not as symmetrical, as I had to clip the port side a bit too clear the entrance. I'll try n get some pictures up soon.

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[IDoSeaDoo]

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[IDoSeaDoo]

Here it is in the boat. I better put the motor back in and see how things sit with the manifolds installed.

The minute mods I had to make to actually get it to fit cost me a little, I probably am right at 35 gallons right now. It's not as much as I'd hoped for, but better than what it was...

 

[IDoSeaDoo]

Finally back at it. Wifey is back home visiting family, so I'm free to build the fuel tank. I've been practicing all weekend using the rail saw, bending, and welding. It's been a while since I've done this, but results are looking promising. This Makita rail saw is a beauty. My new favorite tool! I'm getting cuts accurate down to a mm.

I'm going to err on the side of caution and overbuild this thing. I'm not playing around with gasoline!
My plan is to bend the entire bottom piece, excluding the bottom troth. Going to build and weld that on later. Including that is going to make bending the bottom EVEN MORE complicated. It's ambitious enough as is, and a bad bend results in other dimensions getting screwed up. It all builds on itself. Measuring 17x, cutting once, bending once [emoji106]
Got the bottom piece cut out and measured. Tomorrow I'll do the scoring cuts (to bend along), then cut out the rest of the pieces.