rev problem @5000rpm

[RB BOY]

yeh i have a problem, when i put the foot down on my skyline gtst, i get to about 5000revs and it starts to make a little rattling noise. do u know wat this may be?? or any thoughts? let us know!!! when i get past about 5800 it goes away so wat is it.

[[ant]]

wheres teh rattling coming from? does it do it all the time? does it do it both in the heat of the day and also cold of night? does it do it with different types of fuel (like U98 or a lesser quality one) ?

could be many things, or could be pinging/pinking/detonation ... very bad haha

[awurth]

if it sounds like nuts and bolts rattling in the engine bay it sounds like a bit of detination to me.

[KamikazeR33]

knock knock

[RB BOY]

it cant be the fuel because i put ultimate 98 in it and trustr me thats the best!! maybe when the mechanic tuned it he tuned it too much or something i dont know

[RYanR31]

sounds bad, if i were you id take it back and say its detonation, for now, id retard the timing a little to be on the safe side, or just not thrash it. rb25s dont like detonation

[wannabe]

I had these symptom and it turned to be a case of detonation. Thus it sounds like detonation to me also. If it is detonation and you have a stock ECU chances are the car has set it self to limp home mode and you are gonna be missing some performance. Like everyone else has said i reckon that you should get it to a reputable mechanic!

[Pandaemonaeon]

What sort of boost are you trying to run. They should never do it on stock boost but when you get near to 0.8bar they will.

[QuickR33Melb]

Ive had problems similar and it was detonation. Clean coils, plugs and see if this helps. I had the same problem at about 5000rpm right before I lost my turbo (on standard boost no less) . Funnily enough the car drove like an NA skyline when I blew the turbo to shreds and I drove it around for a week while I sourced parts.

Anyway not to go off on a tangent, take it to a dyno facility. Its so cheap and is honestly the best way to work out whats going on. If you are running lean or have spark problems a $50-80 dyno tune is alot cheaper than having a new turbo fitted or worse for $1200-2000 and it will pick up the problem no worries.