what does knocking sound like?
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Joined: Apr 2010
Posts: 48
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From: Garfield Heights, Ohio
Car: 1987 BMW 325is
Engine: M20B25
Transmission: Getrag 260
Axle/Gears: 3.73 LSD
what does knocking sound like?
i ws putting in gas for the first time. the guyi bought it from said he always used 93 octane, but since the car has a stock 350 spec cam and "high output" 305 heads, i figure it doesnt need it. i put 89 in and as i was filling it, the car started making a loud, sputtering backfiring type noise for a few seconds. would this be knocking, or just bad gas or something similar? i mean now that i think about it i guess the 305 heads could have higher compression depending on what they are, but still...
damn- i just realized i posted the same question twice, trying to figure out how to close this, sorry
damn- i just realized i posted the same question twice, trying to figure out how to close this, sorry
Senior Member
Joined: May 2006
Posts: 581
Likes: 0
From: NY
Car: 00 SSEi / 94 C4
Engine: 231 / 383
Transmission: 4T65E / ZF 6sp
Axle/Gears: 2.93 / Dana 44 3:45
Re: what does knocking sound like?
the 305 58ish cc heads will make more compression...
detonation ping sound.. ( is like a very small hammer rapidly tapping metal. lite case.. not very loud.. or a ring sound )
your combo needs to be tuned better.. to much timing?? AFR to lean??
I can put 87 Octane in my combo without pinging. I'm in the 11:1 range
PS your 2.72 gotta go.. you need to be in the 3 series range
detonation ping sound.. ( is like a very small hammer rapidly tapping metal. lite case.. not very loud.. or a ring sound )
your combo needs to be tuned better.. to much timing?? AFR to lean??
I can put 87 Octane in my combo without pinging. I'm in the 11:1 range
PS your 2.72 gotta go.. you need to be in the 3 series range
Last edited by 88gta3508; Jul 2, 2010 at 10:37 AM.
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Thread Starter
Junior Member
iTrader: (1)
Joined: Apr 2010
Posts: 48
Likes: 0
From: Garfield Heights, Ohio
Car: 1987 BMW 325is
Engine: M20B25
Transmission: Getrag 260
Axle/Gears: 3.73 LSD
Re: what does knocking sound like?
the 305 58ish cc heads will make more compression...
detonation ping sound.. ( is like a very small hammer rapidly tapping metal. lite case.. not very loud.. or a ring sound )
your combo needs to be tuned better.. to much timing?? AFR to lean??
I can put 87 Octane in my combo without pinging. I'm in the 11:1 range
PS your 2.72 gotta go.. you need to be in the 3 series range
detonation ping sound.. ( is like a very small hammer rapidly tapping metal. lite case.. not very loud.. or a ring sound )
your combo needs to be tuned better.. to much timing?? AFR to lean??
I can put 87 Octane in my combo without pinging. I'm in the 11:1 range
PS your 2.72 gotta go.. you need to be in the 3 series range
Senior Member
Joined: May 2006
Posts: 581
Likes: 0
From: NY
Car: 00 SSEi / 94 C4
Engine: 231 / 383
Transmission: 4T65E / ZF 6sp
Axle/Gears: 2.93 / Dana 44 3:45
Re: what does knocking sound like?
Thank you,, you forgot to mention thats was a STI
there will be no need to tune.. deleting the air smog. due to it's not affecting your engine
yes.. I have cranked almost every setting to get my combo to run like it does
the headers are just EDL 6872
the ECU is fine.. I like to de-solder the eprom.. solder in a ZIF socket and flash my 27c256 EEproms.. you could get the ROMulator
http://secure.transtronics.com/osc/p...roducts_id/328
there will be no need to tune.. deleting the air smog. due to it's not affecting your engine
yes.. I have cranked almost every setting to get my combo to run like it does
the headers are just EDL 6872
the ECU is fine.. I like to de-solder the eprom.. solder in a ZIF socket and flash my 27c256 EEproms.. you could get the ROMulator
http://secure.transtronics.com/osc/p...roducts_id/328
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