Avantgarde

I have a 5bar on the way, but am curious to understand where and why the crushed 4 falls short.

surfnturf

Have you done any high speed (140+) runs like S4sideways and gotten the bog or not gone that fast yet? When I replace my howling k03s I will probably go for a true 5 bar, but not having to buy a TCD or MBC is nice (although I have a spare MBC from a 1991 Probe GT drag car).

vegasS4

it is running at basically the max fueling capabilities of the stock injectors. So the little bit more fuel achieved by an improperly crushed fpr can cause misfires as it did in my case. My crushed 5bar fpr came from a friend who had gotten it from machV motorsports

Avantgarde

I think S4sideways may have some other issues, maybe its the rear valance creating drag ;-)

I will try to get some decent logs some night this week, probably won't wind out 6th on the public highway and do not have any planned track time before the snow.

I think you would be foolish not to go with the true 5bar - I just happen to have the crushed in there for the time being.