i have a 2000 model with the stock twins fitted and if i start the car after it is hot, with intake air temp above 60 degc (as shown by pfc) it will boost to zero on the boost gauge and no more. What could be wrong

 

That's a good thing mate, 60 degrees is WAY too hot!!! Boost at that temp would probably lead to predetonation with a quickness...

 

just when normally driving i have intake temps of 40-45 degc is this an ok temp

 

dude, check your ducting, and everything else that can influence air temp, 60*C is absurdly hot for intake temps. My bet is stock IC with no duct, and some other issues that need to be worked out, or just a faulty AIT sensor. Either way, it should be looked at.

 

40-45 is kinda high. Of course a lot depends on ambient temperature, intercooler type and ducting, A/I, etc.

With my VMIC I stay ~10 degrees above ambient, and with A/I my temp drops futher under full boost due to the water/meth spraying.

 

60c doesn't seem that high because he said after the car was hot, and he restarted the car. So I assume he's drove the vehicle, and parked it for a short period of time. Its naturally going to heat soak, and when you first start the car its going to have high intake temps. Obviously it will cool down once he gets moving.

That doesn't explain why he has no boost though.

 

^ This. I have a Greddy FMIC, and if I park somewhere on a hot day it will undoubtedly heatsoak. When cruising on an average summer day I'd like to say that I'm somewhere between 40 and 50 deg C. On a summer night I'm between 30 and 40 deg C.

It does suck though when you park somewhere and it heatsoaks. Takes a while to cool back down. I, as well, have a water/meth setup. I'm running the coolingmist dual nozzle kit. My intake temps maintain, or decrease slightly, while spraying boost juice.

 

yup... it shouldn't affect boost really. It should affect fueling and timing though if IIRC.
i've been boosting hard at the track and had intake temps up to 70C on a super hot day with stock twins. Granted I was beating the hell out of the car on a course that is nothing but short hard bursts of acceleration, and that was at the end of the session on a 30C day, but it's not unheard of. Fab up a little intercooler sprayer, and throw some meth/water injection at it, and check your AIT sensor. I'll probably end up replacing mine and relocating it so it doesn't get as heat-soaked.

Matt

 

ok sorry everyone i will explain more.
I live in townsville north qld it is winter now and daytime temps are 28-30 degc with humidity 90+%.after driving the car hard as always and parking ie heat soak(at least 5 mins b4 intake temps exceed 60 degc,engine temps reach 120 degc) then when car started and driven it will not boost until intake air temps drop below 60.yes i know i definetly need to do the fan mods to make them run after car turned off cheers jason

 

sorry, your winter ambient temps are 28-30C? wow. What's summer like there then? Maybe i should consider relocating! We're getting the August cool-off here in Ontario, Canada. Mid 20's for highs, and low teens at night..

 

The fast reacting iat sensor found on www.wannaspeed.com will fix the heat soak issues. It's much better then relocating the sensor. (I've tried both ways, including shaving down the stock one) Running an open element sensor is a must have mod in my book.

 

+1 for the sensor. I got one and it is significant faster than the stock unit.

And holy ***** I want to move to the land down under. That is some great winter weather!

 

That's funny. . .I know what you meant, but it would be nice if the sensor actually "fixed" the heat soak problem. lol. I have the fast reacting sensor and hit 60 all the time in Atlanta summer around town after heat soak with the pettit SMIC (not the big one). I'm switching to vmount soon.

 

update prior to this problem i removed the air pump and replaced cat with mid pipe. i plugged the pipe that the airpump was connected to (blows air out of it) with a bung that wasnt a tight fit, after driving around the bung has been blown out of the pipe then the car wouldnt boost at all when hot and the charge control actuator wasnt pulled in. i have completely blocked the pipe that used to go to airpump and now the car boosts no matter the temp whats goin on here?

 

Oops yeah, it won't actually prevent the uim from absorbing heat, but the sensor itself won't heat soak. It just reads the temperature that's there. Unlike the stock one which is a big chunk of metal that takes ages to read the actual air temperature.

 

You guys are lucky, on winter we have here 24-25C min, its summer here and we have as high as 39C (yesterday). My air intake temps when cruising around is always 45-50, and when boosting is always 58+. I just tuned for that as there are a few things hotter than suny ol DR.