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U4 4900 RZR build

I haven't touched my car since January. Wife and I started seriously looking to buy a house at the end of November and are about to clise on one so everything else has kind of been on the back burner. The season at Texplex starts this coming weekend and I'm not even the slightest bit intrested. I'll probably get my car finished up in the next few months once the house stuff settles, and then I'll just randomly show up at different tracks for the rest of the season, kick their asses and leave them wondering WTF just happened. :laughing:
 
JR4X said:
This thing is about to get sidelined for a 4600 bronco build. Bronco won’t be as fast but if it’s more reliable/durable then I won’t even care how slow it is.
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I have more fun in a leaf sprung 50hp samurai than I did a 100 hp 18" travel SxS, and it's broken 1/4 of the time.

That 4600 bronco should be fun.
 
I’m pretty pissed off today. After getting the turbo off I decided to adjust the valves while the engine was accessible. When I pulled the valve cover I found antifreeze in crank case 🤬. Without thinking I just took the head off looking for a bad head gasket or cracked head. Head gasket was good but the head has antifreeze deposits in both combustion chambers. I’m standing there scratching my head trying to figure out how it got in there when I bumped the intake manifold, it tips over and coolant pours out of places it’s not supposed to be. The god damn fluid to air intercooler inside the intake manifold broke and was leaking coolant into the cylinders. Coolant ran down past the rings taking up residence in the oil pan. I had ran it so it did circulate antifreeze through the engine. It didn’t smoke though, and it ran on both cylinders.

I’ve got parts coming, I’m going to get it all put back together and hope that the bottom end didn’t get hurt with a few minutes of idling with milk shake oil. The main bearings are roller bearings so they shouldn’t get hurt. The rod bearings however are babbot. All I can do is flush the shit out of it and hope for the best.

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I did the same thing and the motor was still fine. I suggest a CBR intercooler if you do decide to keep it. Otherwise put a polaris unit in and send it down the road.
 
Cleaned it up good as I could and then flushed coolant and did another oil change. Was all good
 
Could you fill it with atf, spin it with out firing, or idle then drain? My buddy said that does wonders for sludge on neglected engines.

No idea what it could fuck up though, so proceed at your own risk:flipoff2:
 
YotaAtieToo said:
Could you fill it with atf, spin it with out firing, or idle then drain? My buddy said that does wonders for sludge on neglected engines.

No idea what it could fuck up though, so proceed at your own risk:flipoff2:
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I think I’m going to change filters, do two quarts of motor oil and 1 amsoil flush. Idle it for a while till up to temp and drain it. Then change filters again and put the right oil in it. Then change it again after the next race. I see on the internet that people say atf because of the detergent in it. But it also has friction modifiers in it so I’m Leary of that.

That stupid intercooler shit is costing me like $1500 bucks to fix. 🤬 that was a good bit towards my 20 inch wheels for my crawler and 42’s.
 
Sure seems like anyone who does more than just cruise around on dirt road ends up constantly dumping money into these things. Which we should be used to with any off road rig, but I sure wish they were more like a dirt bike than a vw :laughing:
 
That thing right there pouring coolant out where it shouldn’t be really blows.
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YotaAtieToo said:
Does the ic just share engine coolant?
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Yes but it’s still more complicated than that. It has two water pumps and two radiators up front but only one coolant reservoir. It’s hard to trace out but it looks like the pathway is this.

Coolant goes from the engine in the back, all the way up to the radiator in front. Then back to the intercooler in the engine, then back to the other radiator up front. Then back to the engine again. The trans tunnel is full of coolant piping and drive shaft. It’s a spaghetti of coolant hoses and pipes front to back.
 
That sounds overly complicated and unnecessary.

Dedicated engine radiator... Ice chest and pump to circulate cold water to the intercooler... Dedicated oil cooler.

That's how I'd set it up.


Edit: With all that coolant in the intake I'd be 100% sure the rods and/or crank are not tweaked or bent.
 
SLOWPOKE693 said:
That sounds overly complicated and unnecessary.

Dedicated engine radiator... Ice chest and pump to circulate cold water to the intercooler... Dedicated oil cooler.

That's how I'd set it up.


Edit: With all that coolant in the intake I'd be 100% sure the rods and/or crank are not tweaked or bent.
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I think I’m 100% sure. I had the head off and checked it out as best I could without splitting the case. It never hydraulic’d.
 
SLOWPOKE693 said:
That sounds overly complicated and unnecessary.

Dedicated engine radiator... Ice chest and pump to circulate cold water to the intercooler... Dedicated oil cooler.

That's how I'd set it up.


Edit: With all that coolant in the intake I'd be 100% sure the rods and/or crank are not tweaked or bent.
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Ice box only works for short runs. Even drag racing I don't think they have ice left after ~8 seconds?

Ive tried to dream up ways to use snow on a snow run to ice down an IC, but also have it functional without it. The simplest way would just be to have an air to air mounted flat with a shroud on top to shovel snow into, snow melts through and drains away :laughing:

Their system actually would be kinda genius if it wasn't a rear engine and required 2 pumps, which makes it seem pointless.
 
YotaAtieToo said:
Ice box only works for short runs. Even drag racing I don't think they have ice left after ~8 seconds?

Ive tried to dream up ways to use snow on a snow run to ice down an IC, but also have it functional without it. The simplest way would just be to have an air to air mounted flat with a shroud on top to shovel snow into, snow melts through and drains away :laughing:

Their system actually would be kinda genius if it wasn't a rear engine and required 2 pumps, which makes it seem pointless.
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Large ice chest in the passenger compartment full of water and ice is going to last alot longer than 8 seconds unless you plan on using a thermos. Will it be good for a KOH length race.... Nope. Would it be the hot setup for short course racing like the rest of the U4 series is.... Yep.
 
Did y’all see anything about the buyout of the U4 series and the complete schedule fuckery? I want a co-driver most races so nowhere to put a big ass water tank.
 
JR4X said:
Did y’all see anything about the buyout of the U4 series and the complete schedule fuckery? I want a co-driver most races so nowhere to put a big ass water tank.
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I read something, could be a good thing once it shakes out?

What about just going air to air and ditching the weight of all the coolant filled lines and coolers?

I guess if you're selling, just get it back together and send it down the road.
 
YotaAtieToo said:
I read something, could be a good thing once it shakes out?

What about just going air to air and ditching the weight of all the coolant filled lines and coolers?

I guess if you're selling, just get it back together and send it down the road.
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I haven’t decided for sure what I’m going to do with it. Trying not to make a permanent decision when I’m mad at it. Lol. The next race got canceled on us, one I was looking forward to and replaced with one I’m not looking forward to and two weeks sooner. The way the whole series works changed and to do the series I need to be in Jay Oklahoma by this Thursday night which is impossible for us with either car.
 
Dude. You're making this too complicated. CBR intercooler and move on. Seriously. I've had this exact same issue, got a cbr intercooler and it's been perfect since.
 
tribal4krawler said:
Dude. You're making this too complicated. CBR intercooler and move on. Seriously. I've had this exact same issue, got a cbr intercooler and it's been perfect since.
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I’m not making anything complicated. I bought a EVP one and going to put it back together the way it was and run it. I had already purchased the Evolution Power Sports one before you said anything
 
As usual, I, with a little help from slow poke, was the one making it complicated.:flipoff2:

If you're there, may as well upgrade. Worst case, it's one more selling point.
 
Every time I work on this thing I delete more plastic. Full bed deleted to make accessing the engine much quicker and easier. Had to make a basket that bolts to the chassis for a place to mount the air pumper, and still keep a jack and tool bag on it. Potato pics in my poorly lit garage. Last pic is the new ceramic coated exhaust pipe, no performance gain there but a nicer piece to replace the Polaris one I can’t get the busted 02 sensor out of.

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Engines all back together and sounds good. Now my batteries are junk so gotta replace them before I can drive it. Also got the right plugs for the big turbo and hot tune in it. Plug on the left is NGK crap I’ve been running and the plug on the right is the Brisk.

I bought good head studs and a cometic head gasket for going back together. I think it already had ARP head studs but I replaced them anyway.

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Looking good, don't sell it.


I don't think your going to like the helmet pumper in that location. It's going to be sucking in hot engine air the whole time. It won't be that horrible for go fast stuff but when your crawling it's going to be hot a fuck IMO.
 
SLOWPOKE693 said:
Looking good, don't sell it.


I don't think your going to like the helmet pumper in that location. It's going to be sucking in hot engine air the whole time. It won't be that horrible for go fast stuff but when your crawling it's going to be hot a fuck IMO.
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I know, I moved it all over anywhere it would fit but that’s the best and only spot I can put it. On the other side it’s above the exhaust. Hoping that when moving it’s getting cooler air. But I’m sure I’ll be sucking heat while waiting for the flag to drop. It was in the bed before with all the crap between the pumper and the engine, it just won’t fit anywhere other than the bed area.
 
JR4X, wanna try short course racing without having to drive to TX? Coming soon.....

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Moab U4 is in 2 weeks, I feel like this is the universe trying to tell me something. I’ve spent months and thousands of dollars trying to get recovered from Oklahoma finals and the first race is …. Moab. 🤬
 
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