I drive a 88GXL NA 130k miles, been taking care of her, but when I drive her hard (gaining to 120mph) in the acceleration range of 80mph to say 88mph - that 2 seconds has the engine (I'm assuming) make a different sound. And it's only for a slight bit; almost a under-toned grinding sound, very subtle rattle, then after the range, it goes back to normal progressive rev sound. This has me worry that it might be first signs of detonation?

Was wondering if anyone could post a video with the sound the 13B makes when our engine starts to go through detonation. And also if anyone knows what other else this sound could be? I hope it's not the sound of my seals getting old and grinding... Erm but my compression test read perfect for all six seals (for my miles-wear anyway) Ugh something loose could be just rattling? Zzz, but why does it ALWAYs -only- rattle in that range? Hmm,

Thanks in advance.

 

Maybe you can post a video of it happening?

 

I doubt you are seeing detonation, and it is certainly not the seals grinding (that will never happen unless something is broken). Most likely you just have a small mechanical issue somewhere. Heat shield or shifter rattling, etc.

 

I'd agree that it's probably something metal rattling or some bearing noise. It's very hard to detonate on an N/A engine, unless there is a serious problem with timing or fuel delivery. Detonation kind of sounds like a hammer banging on a solid block of metal.

 

Yeah you're right guys... it isn't detonation - I was just worrying too much; certainly doesn't sound like a hammer knocking on metal! So I'm good. Probably just is something rattling like you said. Hmm, heat shield: have to look into that.

I might post a video later if I can figure out how. But thanks guys