Hello,

I understand that when I first start my car, I should drive it at low RPMs (under 3000) and off boost until warmed up. I live in a very hilly area so at times I'll accidentally hit boost for a second and then back off til it's warmed up. No big deal.

However, if I accidentally hit boost prior to the engine being warmed up, I can hear a sound from the turbos that concerns me. Not a whooshing sound, but a sound that sounds like they are not sufficiently lubricated. After a few minutes, the sound is gone. I am running correct boost patterns.

Is the sound just because it takes some time for the oil to circulate around the turbo bearings, and hence why we should drive off boost til warmed up?

2 reasons I'm conerned about the noise:

1. I used to own another 3rd gen a few years ago and don't recall it doing this.
2. I just noticed my lower intake hose is slightly split. Is the lower hose the one that would feed the turbo that activates at low rpm or the turbo that activates at 4500 rpm?

I should have paid closer attention to the maintenance records that came with the car when I bought it. 1800 miles ago, a record shows that the hose was temporarily repaired with black tape and the hose needs replaced soon. The tape has melted somewhat and come loose which exposed a very small open area. I'm concerned if some dirty air (flipping off the spinning pulley) could get in there and gradually cause damage to that turbo.

I'd appreciate any input on this.

Thanks,
Tony Alvarez
93 Rx7 base
94 Camry

 

tony,

its hard to diagnose sounds w/o hearing it. maybe a forum member that lives nearby can take a listen? any volunteers? or you might want to consider taking a drive to KDRotary.com in PA.

you might want to replace those rubberized hoses with some "hard pipes". this dude huybiz sells them on ebay for ~$130. they will never rip

lastly, wouldn't worry too much about some light boost while the car is "cold". so long as the car has been running a few minutes, oil and coolant will be running throughout and doing their job.

obviously you want to wait till the motor, tranny and diff has been rotating for a while and the oils therein have warmed up to operating temps before *beating* on the car and going full boost.

 

Thanks for the info Alberto.

George Dodworth of Sevenspeed (a Pittsburgh shop that specializes in Rx7s) will be seeing the car in about a week to install my downpipe and pfc. I'll try leaving it with him overnight to see if he can replicate the sound and advise what may be causing it.

I found the Rx7store hardpipe kit from a member on this forum that I will be buying. Talk about good timing that he just happens to be selling right when I need it

Tony

 

To answer one of your questions, the lower intake hose goes to the primary turbo, which is the one that activates at low rpm. Hopefully none of that tape got sucked in!

Good luck.

 

double post... sorry

 

Thanks LA racer. That was my concern too about the melted and worn out tape getting sucked in. Well, I'll be getting some hardpipes soon so my car will stay parked til they're installed.

Tony