Losing Power After A Long Session Of Thrashing

[nisskid]

so the story is, ill go out to a drift praccy, and at the start of a night ill be able to feather 3rd around a certain corner, but by the end of the night on the same corner with the same tyres (or close enough), ill have to kick the f**k out of the clutch just to keep it going.

i also seem to notice a point in each session where i notice a bit of dullness in acceleration from what im used to, this makes me think the loss of power happens fairly quickly, but i wouldnt rule it out happening over a period of time.

things to know are:

RB20DET

RB25 turbo (still running heat shield)

split dump with screamer

FMIC

pod with home made heatshield

040 pump

no apparent overheating (according to standard gauge lol)

remapped ECU

around 12psi from a pneumatic controller

everything else engine wise is standard.

so whats everyones thoughts?

[WYTSKY]

hmm.. so you dont have a complete exhaust system?

I'll tell you my experience because it seems similar.

I have a full exhuast system, went from a gutted cat and a leaky front pipe to nice non leaky system and a metal highflow.

we dynoed the car after this and after a few runs she started to loose power.....

tuner tried a few things(thought was a leak), couldnt find anything.

we let the car cool for a bit, the cat was ticking like crazyy... after it cooled down a little we chucked it back on.

all the power was back and everything was fine....

so I knew the cat was going to be a little more restive, but after each run it was loosing ~2-8rwkw.

perhaps thats why after a few laps of you thrashing the car it feels a little more slugish...?

gl with it.

BTW... i dont like your sig!

[SLAPS]

Double check the engine temp and if possible the inlet temp.

Any where from low 70-110degree's my standard temp gauge sits on half. Only once you start to creep past 110degree's it starts moving off half.

Unsure with the std ecu however I presume it would contain ignition and fuel trim as engine temp pushes over a certain point.

Mine starts to pull out any where up to 3-4degree's by the time engine temp is at 110degree's as well as richen it up 'slightly' to prevent ping.

It may be detonating slightly when hot so the ecu drops back to the low oct map?

Unless your running a nismo thermostat, nice alloy radiator and have retained the std viscous fan I would thing it will be pushing close to 110 degree's when your stuck up it for some time.

Edited February 18, 2009 by TheRogue

[limpus]

Could be heat soak of the intercooler and a general rise in engine bay temps robbing you of power...it might not be enough to cause water or oil temps to overheat but it will definitely cause a drop in power...as you progress thru your session heat builds up obviously...and from session to session i doubt your engine would have cooled down completely...

[Guilt-Toy]

bring 2 - 2 litre bottles of water with you. after every drift run pour the water over the radiator and intercooler while it is still running for about 2 minutes, then shut down the engine and pour water over it ever 5 minutes untill you run out of water, then re-fill the water for the next run.

If the issue goes away then its definatly heat soak, you can keep doing this as it will help with heat anyway.

[blow thru]

bring 2 - 2 litre bottles of water with you. after every drift run pour the water over the radiator and intercooler while it is still running for about 2 minutes, then shut down the engine and pour water over it ever 5 minutes untill you run out of water, then re-fill the water for the next run.

If the issue goes away then its definatly heat soak, you can keep doing this as it will help with heat anyway.

This is heat soak underbonnet temps get f*kn hot as in a skyline.You could try raising the rear of ya bonnet, undo the bolts an put about 5 -8 washers inbetween the bonnet an hinge an also remove the rubber strip that seals the bonnet on the bak firewall its held in place by clips so just use pointy nose pliers to pull them out.