RB20 in a Silvia: RPM's Drop When Brake Applied

[dbiz]

i literally just had a 240 delivered to my house with an rb20, and it idles at 1.8k before warmup.. i was told thats normal?? lmao anyway when i apply the brake (clutch in or in neutral), i hear a loud ass leak-like noise, just sounds like air pouring out or some shit, and the rpm's just start to drop. previous owner told me to just tap the gas once or twice to keep it up. i havent really checked it out or tried to find out what it is yet. any ideas what it could be??

[Yellow4g63]

LOL sounds like you have a huge vacuum leak. They prob turned up the idle to try and keep it running. My rb20 idles at 1200 for a short period but that's because I have big cams. Hope you didn't buy the car without getting it checked out 1st by someone who knows wtf is going on.

[dbiz]

LOL sounds like you have a huge vacuum leak. They prob turned up the idle to try and keep it running. My rb20 idles at 1200 for a short period but that's because I have big cams. Hope you didn't buy the car without getting it checked out 1st by someone who knows wtf is going on.

according to the previous owner he cleaned the iacv and it didnt do jack. and yes i am guessing your correct. will update tomorrow lmao

[Yellow4g63]

Not looking too good man. People lie all the time, it could have been a hack job too.

[Frank_Jaeger]

Check brake booster check valve, and all vacuum lines.

[Perfect Balance]

I would definitely check the brake booster, especially since pressing the brake makes noise like you describe.

[Hellother]

Check brake booster check valve, and all vacuum lines.

This........^^

[TougeSR20Kid]

Most likely brake booster... Do you have normal pedal feel the first time u press on the pedal after the engine is off? Also how does it feel when the engine is on? Hard or normal? Good news is if it's what I think it is, it's not too bad