Hey guys,
Pictures (1000 words):
http://members.optusnet.com.au/govich/dynos.jpg
Left is the current dyno sheet, right is a year ago.
Words:
I've recently run into this problem where my R33 will make good power to 4500rpm and then just runs out of puff completely. It's a stock RB25 running a stock turbo with the usual mods; intercooler, boost controller, e-manage ultimate, exhaust cam gear, turbo-back exhaust. No power mods were added or removed between those two dyno runs. The AFRs are fine, ignition timing seems fine, it makes the same power to 4500 which leads me to think compression is fine, the cat converter hasn't collapsed (visually the internals look fine) and i can't find any obvious exhaust restrictions.
This leads me to the stock turbo which has started exhibiting a faint whine at all engine speeds (changes pitch with speed) but the thing still builds boost instantly and easily holds 10psi until redline (see dyno graph). From the dyno graph it seems like an airflow issue somewhere and i'm going to start pulling the car apart soon but just wondering if anyone has run into something like this and could save me some time.. The turbo is still my main suspect but i don't really know how to test this other than simple shaft play tests and having a physical look at the thing, short of taking it off and sending it to GCG or similar.
Any comments appreciated. Cheers guys
govich