Challenger 180 255 Max RPM Question

[kyler413]

So those with a Challenger 180 255 what is the proper stock top end RPM?

Long version, I just picked up a project boat, a 2010 Challenger 180 255 with 68 hours on it. First time playing with the 255 motor.

It was supposedly sitting for a while in storage after the prior owner sold their lake house but they got it running and test drove it and it ran in the mid 7400 rpm range but the dream-o-meter said we were doing 52 with a light load and that seemed fair. Although had a seemingly random single short beep that would happen every few minutes or so but not in an organized pattern. No real rhyme or reason to it. Hooked up the candoo before paying and no real code issues (low battery a few hours back and wrong key.)

Got it home as with when I get a new to me “toy” drained the tank checked the filters and wear ring, Changed the plugs but they were rather clean. Oil level was high, roughly ½ inch above the top bend but did not see water in oil so assumed the shop who did the last oil change didn’t do it right and didn’t remove the oil properly. Pulled some out to get it to the upper end of the bend. Coolant level is on the low end but still within the lines. Looking online I should be seeing moderately more RPMs in the 7800 range for the 255 or am I not understanding it right. New fuel had it max out at about 7450 rpms, no cavitation issues as long as you ramp the throttle and not slam to the stops and the dream-o-meter says 53 on a smooth lake, so those with a Challenger 180 255 what is the proper top end RPM?

 

[dsm]

In my experience it depends on the amount of weight in the boat. With just the driver on smooth water I can almost but not quote hit the 8000 rev limit. My normal load of 4-6 people its more in the 7800's like you have seen elsewhere. I think your 52-53 speedo reading is a bit fanciful especially at the RPM you are getting.

 

[kyler413]

Oh I have absolutely no doubt about the Dream-o-meter being wishful.

What could cause the RPM to be lower like that? the motor seems to be running smooth any suggestions? I am in Texas so at 750 above sea level so it is not elevation. New plugs, new fuel, clean fuel pump filters (inside and out learned that from my ski).

 

[dsm]

The supercharger clutch could be slipping. You can check the "slipping moment" without taking the supercharger off of the engine. Reportedly you can do a quick and dirty test by just removing the inlet hose and making sure the wheel can't be turned with finger pressure, though I haven't tried that myself.

If the oil was changed with the wrong type it could maybe cause the clutch to slip since the clutch is lubricated with the engine oil. Since you already know it was overfilled it might not be a stretch to think they might have used the wrong oil also.

The shop manual says if the supercharger inlet is dirty it could cause low RPM at full throttle. I haven't heard of that actually happening to anyone though and with 68 hours how dirty could it be?

Search the forum for supercharger threads.

Otherwise, low fuel delivery? Dirty injectors or low fuel pump pressure?

 

[dsm]

Oh, also since you mention you have a Candoo, see what it says the intake manifold pressure reaches. You might want to clear it before you run the next time after checking everything else so you can get a new max reading. I don't know if there is a published spec, but is I recall correctly maxes at a little under 25 PSI (about 10 PSI of boost).

 

[kyler413]

I will try that tomorrow and keep you posted. YouTube here I come on the slipping test

 

[kyler413]

Ok, changed the oil, no change in RPM max, still maxed out at roughly 7400.

The random beep went away when I found a bad fuse on the regulator. Noticed as the candoo was showing less than 12V operational voltage.

I guess it is digging into the supercharger next... any other suggestions?

 

[MacSeaDoo]

My intercooler was leaking and I was around 7600 rpm max in my 150 speedster 255.

New intercooler now has me at 8100 rpm.

Also had a bunch of surging and the odd dead spot when you would advance the throttle after running mid rpms.

I pulled my SC and it looked new. That was at 74 hours.

 

[kyler413]

Good idea, I'll check that tomorrow, seems way easier place to start than getting to the SC.

 

[MacSeaDoo]

BTW pulling the SC is not difficult. You will need:

1.. e10 boxwrench for the top backside bolt on the SC.
2.. the other 2 are regular torx.

To make it simple.

1.. undo the 2 clamps on the waterborne from the exhaust.
2.. unclip the temp sensor on the exhaust can.
3.. unclamp the water feed from the connector on the exhaust. To top most clamp from the hose coming from the exhaust header.
4.. undo the exhaust connection clamp, the one with the plastic protector in the threads.
5..undo the strap on the exhaust can.
6.. pull the exhaust back while you rotate to move it back in thr boat. Also wrap the rubber hose with something because in my case there is some rough edges in the inside of the above lip.
7.. then undoo the 3 bolts on the SC.
8..you can then just pull it out.

 

[MacSeaDoo]

To test the IC, I pulled it out and made a fitting for the water supply hoses.

Used a tire valve stem in a reducer and a plug for the other hose. With the SC and exhaust out, it is easy to get to the 3way connections that the IC feeds off of. Leave them on and pull it out undoing the cross straps.

 

[kyler413]

So over the weekend did the moisture look test by pulling the hose at the intake of the motor after the intercooler and looking for moisture when at throttle and no moisture was present, the boat is in a dock slip and so didn't have the hose connection method without pulling it on the trailer, but during running at 6k+ RPM there is no leakage of water passing through like I have seen on YouTube videos I guess that means the intercooler is ok? or do I still need to pull and do a pressure test?

That would likely leave it down to the SC, Ill try the "finger spin" to see if that is an issue. Then it is going further in I guess.

 

[kyler413]

So pulled the SC today, got to hate the 106' heat here in Texas. It looks clean but how to I check it?

At this point it is out and even though it has only been about 70 hours and likely never rebuilt I guess it has been 10 years and its going off to rebuild. That way I at least can ride knowing less likely to cause issues for a while.

 

[LionOnABeach]

What year again?
Can you test the slippage on the SC? There’s the tech spec, and then there’s the longevity spec. If they’re 2009 or older (I think that’s the last year, someone else confirm please), you have ceramic washers that according to some, have a propensity to let go and F up your entire engine. If you have it pulled, and never rebuilt and over 150+ hours, just send it off and get it rebuilt. I’m doing that to mine at end of season, since I’m approaching 200 hrs, on ceramic washers.
cheers!

 

[MacSeaDoo]

You need a torque wrench that can work in ft.pounds or NM. I used some cloths with vise grips to hold the gear and then put the torque wrench on the back bolt and was getting slippage at around 11 NM. This was right in spec of 8 to 12 NM. Mine had 65 hours on it and spun freely without any play or roughness. I put mine back in and will take it out again to inspect again at around 125 hours or so. I decided not to rebuild based on my mechanical knowledge and testing it coupled with the availability of getting it back boating. I live in Canada and the boating season is 2 months long at best, so when rebuilding my SC is a 2 week turnaround, my decision points are different.

 

[kyler413]

So had the SC rebuilt, Although was not the problem even though there was what seemed like a little slip in a finger test... While I am glad I know it is good for a while and don't have a time bomb. 7400ish max RPM she runs great but no higher, not even cavitation present which was surprised about.

Little rough idle at start but does smooth out, does make me wonder if maybe dirty injector but I feel that may be grasping at straws? I do know it set for a bit but I drained the tank and replaced the fuel pump filters(inside and outside learned that from the RXP I have) and plugs of course.

As for the intercooler again its dry on the outlet port when I pulled the output to test for leak, I guess I need to play with test fittings next for a pressure test?

Any other ideas about this. I am about at the point of saying it runs and leave it alone but I'm this far in so why not keep at it.

 

[kyler413]

Oh I did replace the air filter also, for good measure....

 

[MacSeaDoo]

I bought the Candoo software for stuff like this because you have to play parts roulette.

 

[kyler413]

I have the Candoo, it does not have any codes or any issues reported that I can see,

 

[MacSeaDoo]

Some suggestions with Candoo..

1.. First, make sure your Throttle Position Sensor is correct. Make sure with the throttles pulled back you are zero and you should be around 83% at full throttle. (FT is 90% and idle is 7%)
2.. Make sure your intake temp sensor is reading correctly to ambient. if this is off it affects throttle maps due to temp vs. airmass.
3.. Make sure you are reaching full boost. Do a FT and make sure you are getting 10-11 PSI off of station pressure. (If you are sea level, that would be 14.7 so total MAP should be around 25 PSI

 

[kyler413]

1) Ok so the TPS at idle is 0.1 at full throttle is 83.26
2) Temp sensor at ambient seems within a degree or so of what they say the temp is, being the shade I can assume pretty close.
3) Boost gets up to the 24 mark per Candoo history, will try a full rpm run later tomorrow hopefully.

Any other ideas?

 

[kyler413]

Changed the fuel pump and now it is back in business. Changed the filters at the start but must have been a weak pump?

 

[Scriz]

I appreciate you actually posting what was wrong. I have read so many of these threads that just end without the OP actually providing what fixed their issue.

 

[MacSeaDoo]

You need a torque wrench that can work in ft.pounds or NM. I used some cloths with vise grips to hold the gear and then put the torque wrench on the back bolt and was getting slippage at around 11 NM. This was right in spec of 8 to 12 NM. Mine had 65 hours on it and spun freely without any play or roughness. I put mine back in and will take it out again to inspect again at around 125 hours or so. I decided not to rebuild based on my mechanical knowledge and testing it coupled with the availability of getting it back boating. I live in Canada and the boating season is 2 months long at best, so when rebuilding my SC is a 2 week turnaround, my decision points are different.

I edited my post to reflect my change of opinion on the time aspect of rebuilding your SC. The gear side bearing race of mine just failed at 87 hours. The SC is largely intact, but needs to be rebuilt.

As others have mentioned, the plastic races appear to get brittle and break over time. I am not sure I would do it at 2 years but I would definitely not wait for 8 years like mine.