Pinging Problem After Fitting Flat Top Pistons

[sasenz205 0]

Hi there as you can read on my heading i have problem with pinging, i have recently put brand new wossner flat top pistons from a 1.6 gti on my 1.9 gti, and now i get pinging on low revs, i have tried puting high octane fuel 98bp ultimate and a octane booster + retarded the ignition timing and it still pings.... i am using champion spark plugs, anyone can share a light on that:)?

[dcc 855]

Have you worked out cr? Whats spec of engine? Standard ignition?

[welshpug 1,661]

were they high comp pistons or standard compression?

 

do you have a recurved dizzy or mappable ecu?

[sasenz205 0]

Have you worked out cr? Whats spec of engine? Standard ignition?

I have compression of 320psi on each cylinder across , its a d6b engine, ignition is standard

[sasenz205 0]

were they high comp pistons or standard compression?

 

do you have a recurved dizzy or mappable ecu?

They are hi comp forged flat top pistons, i dont have a recurved dizzy or mappable ecu

[jackherer 543]

If 320psi isn't a typo you must have a ridiculously high compression ratio.

[welshpug 1,661]

you need diesel in there...

 

1.6 pistons only work in a 1.9 if they are standard compression which gives around 11-1.

 

you're probably over 13 at a guess

[petert 588]

Maybe your cam is advanced too far? Are you sure it's timed correctly?

[rallyeash 155]

Drain the petrol. Fill with Diesel. Job jobbed.

 

That must be a typo? My compression gauge doesn't even go up that far I don't think!

[welshpug 1,661]

Drain the petrol. Fill with Diesel. Job jobbed.

 

That must be a typo? My compression gauge doesn't even go up that far I don't think!

quite an amusing post given the pistons youre trying to sell yourself, given you also haven't a clue of the specific dimensions.

[ALEX 98 1 Cars]

Last months (or month before) Practical Performance Covered an interesting article on chamber design, presumably explaining the reason of the change in design when developing the XU from flat top to dished. (Dist arrow pistons)