Well if that's the case then sounds like you found a problem, or one of them. Is the cushion even present? Must be a hell of a leak if you are taking what I assume is a standard 100+psi compressor and cant even charge the manifold over 6psi Not that I would ever suggest you try and push 100psi through the manifold to test for leaks and risk blowing things like injector seals. I'm still a bit suspicious of what's going on there without seeing it, but we are at a disadvantage being behind a computer. But before even doing the pressure test I would have insured your belt has proper tension to eliminate that as the main source ...and considering your unfamiliarity with the kit and how to tighten the belt, I would have liked to seen posters work with you on that simple task first and foremost before getting bogged down into potential diversions or unnecessary purchases. Your sort of working in a round about way then how I would do this. But felt the need to step in at this point and help guide things along after some of the post I was reading.

Food for thought, when a sc belt is not tight enough and starts to slip, its always around near where the motor makes max trq, so near the top end around the 7500k rpm range. Its due to the acceleration/spool up of the motor and so its also more likely to slip in the lower faster accelerating gears as well. Another verification of this is to see if there is any change in boost through rpm in say 2nd gear vs 4th gear, though I realize on the street that isn't always safe or practical to do, but again its food for thought anyway on understanding how to easily troubleshoot. A simple re snug of the belt and boost monitor can give you direct feedback on if that was the source or not. If you continue to tighten the belt and you see no change in boost then you know its more likely a boost leak.

 

Thanks for the feedback. Hope it didn’t sound like I think the boost leak is the main problem, and the one causing boost to suddenly drop off. That’s most likely belt, and that is the thing that I’m pinning my hopes on for fixing it. That it happens at max torque sounds like a good theory, and one I’m happy to go with for now.

That said, having a serious leak around the injector closest to the firewall means I’m most likely dealing with two problems. I don’t like having that leak, so I’m fixing that regardless of the belt. These forums are such an important resource for me, so I figured my way of giving back is documenting this really well for whoever comes after me and experience the same kind of problem. (I find it so frustrating searching and finding threads where someone had a problem and there were like 3-4 suggestions for what it could be, and then you never hear back...)

Anyway, I’m already in love with my first S2000, and this thing is going to get babied - no expenses spared

 

 

Having a leak at a lower injector cushion is not uncommon when you do not have pressure at the rail. The relative 43 PSI should always be on top of the injector pushing it down. If you cannot verify this and you only had one seal leak... Verify you have fuel pressure on top of the seal and do the test again.. I deal with this regularly with having customers perform boost leak tests on their cars.