Strange dip on my 4AGZE Dyno

[beeker]

what's with the dip at the top of the graph ?

There was a chap there on the day that said this was common ??

Naturally, I would like to fix it! Anyone seen this before ?

See Dyno chart here:
http://photobucket.com/albums/b239/noelsimpson/?action=view&current=Levin4agze.jpg

The 4AGZE came from a AE101, and is running the stock AE101 ECU.

[Lloyd]

Chances are that thats at about 5500rpm, pretty common on the 4AGZE. Think its due to ECU dumping a fair bit of fuel in for safety reasons but people all seem to have different theories on it. Best way to fix it is get an aftermarket ECU and a turbo

[evil_si]

my theory is its a safety warm up prevents full power when engine is cold , on the cars ive played with, it only occured within the first 10-15mins of engine running, and if the car was stopped and restarted the safety started again.
on my dyno chart, at 150 it dropped down to 80, then after 15mins of running it pulled thru to 181

with a turbo or bigger pulley on factory ecu it is a lot more noticable.

[EVLGTZ]

yep pretty darn common on the later model 4agzes running map ecu's

Couple of ways to get around it including running an aftermarket ecu or a more recent fix that i've heard of is by replacing the knock sensor.

Some good info on it on the www.twincam.org forums, would post a link but seems to be down at the time of me posting.

Look for the topic Ättention MAP 4agze owners"or something like that