SHO sounds like its turbocharged??

[93MTXSHO]

Why does my naturally aspirated SHO sound like I have a turbocharger? It's most noticable if I have my foot about half into it in first gear. If I rev it up to about 6.5 grand, the noise goes faster with engine RPMs. It sounds just like a turbo spooling. Car has 195,300 miles and I put a timing belt and WP on it at 182, when I got it. I didn't know at that time that it was probably a good idea to replace the tensioner. I've heard that the bearing in a bad tensioner would just lockup. I don't have any belt squeal or anything that sounds like a bad bearing. When I had the tensioner off the car, I distinctly remember it just spinning just as smooth as can be. BTW, car does need a 60K badly. I didn't know any better until recently, so I'm planning it soon. Thanks for any suggestions.

 

[RI-SHO]

Could also be another pulley bearing, most likily the alternator pulley. I get the nice supercharger whine when I rev high too, i'll replace it when I near 9PSI .

 

[93MTXSHO]

I love the comment about 9psi. That's good. Anyway, I have a question. Isn't this a Mitsubishi alternator (I think I read that somewhere) or is it really a Motorcraft? How much should I expect to pay for a rebuilt one? I don't have any charging issues, and am not that worried about it now, but I will want to have a little info for when it fails. BTW, I'm pretty sure it's the original alternator. Can you believe it? 195K and still going!!

 

[SHO Boom]

get yourself a mechanics stethescope (sp?) and listen to various pullies to see which one is making your turbo noise. my stethescope consists of a piece of flexible tubing that i place to my ear and then poin the open end at my target. Good luck

And if i had to take a guess, i would say its one of the accesory belt tensioners.

 

[projectSHO89]

I'll place 10 bucks on it being the PS pump due to air in the system or the pump is shot.

Make sure the the PS fluid level is correct.

Raise both front wheels, start engine, swing steering wheel slowly from stop to stop 15-20 times and see if the turbo sound is gone.

Really persistent problems with air in the system will require placing a 20 inch vacuum on the system while performing the purge.

This fixed my turbo-like whine, which, of course, I had already isolated to the PS pump using a stethoscope as described above. A really long screwdriver will work also. Just hold the handle against your ear and lean the point against the part of the engine you wish to focus on.

Note: Don't touch a moving part with any of these methods. Gets real loud in the ear!

Steve

Steve

 

[sdpatt]

Did you by chance install the Goodyear Gatorback serpentine belts? The cut on the underside of those belts makes mine sound like it is spooling up a centrifugal supercharger. Now I just need a boost gauge.

 

[93MTXSHO]

No sdpatt, no Gatorbacks. That would be kinda cool though, seeing as I definitely knew that's where the noise was coming from. I really think it's the Alternator. I've always wondered about the Gatorbacks though. Are they really worth the extra cash? I've been told that they are the best belt out there, but am never able to fork over the extra cash for them. I really appreciate the replies fellas. One more question. Would it be prudent to flush my PS system? The pump has 195K on it, and I know that you don't change automatic transmission fluid in something with that high of mileage because it will make it slip. I have no desire to replace the pump, simply because it seems like it would be a real PITA. My first inclination is to leave well-enough alone. What do you guys think? The input is greatly appreciated.

 

[RStalveyARFF]

overtightening the timing belt will sometimes lead to the turbo noise...

 

[93MTXSHO]

About that darn t-belt... I was a real greenhorn when my dad and I put a timing belt on this car. It was only like the second one he had ever put on. More of a pain than we anticipated. It took us over 8 hours to get a t-belt and WP on. We weren't sure about the belt tension, so my dad called one of his friends that was a mechaninc. He said that the tensioner should be spring loaded, which it is, and that we should just tighten up the nut there. Little did we know about rotating the crankshaft, etc. I haven't had any problems, thank God, but I plan to give this car a valve adjustment when I'm at home over Christmas break. I'm only recently (like since finding the forum 2 months ago) learning more and more about my SHO and what it really needs to keep it in tip top shape. Should I plan on putting on another belt, correctly this time? Is the current tension too tight or too loose? Have I ruined my belt? Please bear with me. I am pretty mechanically inclined, but have never run into anything like this Yamaha before. I just simply don't understand it. In time, I hope to know as much as possible about this wonderful engine.

 

[pete c]

All this time I been diggin' my cool turbo sound, and now you guys are telling me there might be something wrong. Sheeeesh! Thanks a lot. One more frickin' thing to worry about.

 

[SHOspazz92]

Could it be your airfilter?, i know that when i installed a k&n filter the latches kept on coming loose so it would be loose letting air get in and it would make that noise, and even when i latched it back up it would maek that noise just quieter, so i experimented, put the stock airfilter back in and the noise wasent there, the same noise is in my cousins 90 FOX and he has a k&n