Any history of burning valves with stock EM and larger turbo?

[UrS4boy]

In my UrS4 world, there was a history (about 9 years ago) of people burning No. 1 and No. 5 exhaust valves when they added RS2 turbos (and injectors, MAF, S/W, etc) to their AANs with stock EM (instead of also adding the cast RS2 EM). Was there a similar history here with the 3Bs and ABYs and RS2 (or other non-K24) turbos on stock EMs?

[Greg_S]

Yeah very much so, all 3 engines suffer in a similar way

[Jamo]

Yes it's because of the design of the standard manifold with the high runner joins on 1 & 5.

There's a reason the RS2 manifold was made for the RS2 turbo and I believe the other owners have found out why!.

[UrS4boy]

Yes it's because of the design of the standard manifold with the high runner joins on 1 & 5.

There's a reason the RS2 manifold was made for the RS2 turbo and I believe the other owners have found out why!.

Preaching to the converted here. I believe that Porsche and MTM (with their own manifold) and Wagner (with their new cast EM in the works) all realized there were issues with the stock EM. I've been trying to convince someone who is saying the stock EM is good for 400 crank Hp without issues the error of his logic but he claims that I don't have any data. For my part, we went through this in 1998-99 and people finally understood that their were good reasons to spend the $$ for the RS2 EM when targetting more than stock power.

Thanks for the input.