C160SFG - 1986 Series 3

[ian65]

yeah, it's sounding more and more like the inlet gasket is leaking... I hope not, it means taking the whole setup back off..... a right sod of a job..... I'll check the couplers first for a leak or split

[KiwiDave]

So it's happening on vacuum rather than boost right? (if you recall vacuum gauges). On a boost gauge , idle still registers as negative boost or vac.

[kenwhiteside]

bit of a pain to set up but if you feed compressed air into the inlet (regulator set to 5psi or so, sealed inlet) you can check for leaks using a solution of dishwashing liquid

[ian65]

So it's happening on vacuum rather than boost right? (if you recall vacuum gauges). On a boost gauge , idle still registers as negative boost or vac.

yeah, on vacuum...... as the throttle opens and the vac diminishes, the whistle fades out but with the throttle plate closed and the manifold pressure very low, it's drawing in air from somewhere, giving me this whistle.

[Ghostkls]

If you worried about spraying things around the engine, a spray bottle with some soapy water should do the trick of finding your leak.

[RamoNZ]

Only thing I can think is that if the sound takes a while to go away then the vacuum must have a reservoir - I.e brake booster?

Did you put a 1 way valve in between manifold and booster? Could have popped the diaphragm...

[ian65]

No, I didn't use a 1 way valve, but I didn't on the black car that i converted to Elford turbo either and that was ok..... the servo seems to be working fine...... if I pull the pipe off the wastegate actuator, then that allows more air into the inlet and raises the air pressure back towards atmospheric pressure so the noise stops but as soon as I put my finger back over the end of the pipe, it whistles again straight away as the inlet is almost sealed and the the manifold pressure drops again and then draws air in through the point where the leak is, causing a whistle. Finding the leak is proving difficult..... access is a sod with the turbo and all the rest of the stuff in the way.
I'll unplug the servo tomorrow and plug the pipe off the inlet which will at least let me know if the servo has got anything to do with it. The pipe to the servo comes off the carb mount before the compressor though so it's only getting vac, not boost.

[RamoNZ]

Ok cool. Well of the diaphragm isnt compromised, it could still be the seal - over time the grease moves out of the way of the oring and can leak. Easy to pull apart and re seal if it is the problem.

[ian65]

My UK market series 3 RX7 FB
Sunbeam silver
Built: 1985
1st registered: 27.03.1986
52,000 miles
12a Elford Turbo engine running stock boost, TII oil cooler, MR2 twin E-fans with Autocool, LSD, Energy Suspension Polys.
Aus spec aero mirrors, 12at cluster, TII leather seats

[ian65]

Changed my front number plate from this....



to this...



didn't know if I would like it but I actually think it suits the car.



.