Rattle under load on new build

OAKMERE

Since my remap I have started getting a bit of a strange metalic slap / rattle sound in high gear at lower speeds. Fifth gear 40-50 mph put foot down strange metalic slap rattle sound for only approx 1-2 seconds. Quite at idle and when the engine is cold. If I go on and off the accelerator it stops untill steady driving and I put my foot down again?
Any ideas

vocky

piston slap or knock would be my guesses :nailbiting:

OAKMERE

Thanks Vocky it could be knock but this was checked for in the logs after the remap. On the drive back from CS it only started doing it after about 2 hours of driving?

JohnnyN

Only under load? Sounding almost like a loose chain? Have you got a lightweight billet flywheel fitted?

OAKMERE

Yes light weight fly and balance delete.

JohnnyN

Mine has been exactly as you've described ever since the flywheel change.

OAKMERE

Maybe somthing to do with the lightening and balence removal. I did think now the balance chain is doing a lot less work and the much quicker acceleration the tensioner struggles for a second. Good to here I am not the only one to have this issue. I will keep trying to get to the bottom of it though.

OAKMERE

Johnny
After a quick search it is called flywheel chatter and is common with lightweight flywheels. This would explain the noise.

JohnnyN

Thanks for that. Never heard of this before. It's been like it for 5 years now so I won't worry too much then. 😉

OAKMERE

Cheers Johnny