I summon the SR tech gods to answer my prayer.

[ka24det-power]

Ok so I am having a little bit of an odd problem. My car runs like a champ for about 1 hour during mid day heat (Florida 96 Deg today). Then all of a sudden like a switch was hit I lose about 30hp. (kind of like when your crank angle timing is way off and the car makes no power)

It idles fineRevs smoothTemp gauge has not movedFMIC is warm on one side cold on the otherMakes a slighty diffrent tone during excelerationI have a 14" and 10" fan on a stock SR radiatorStock termostat

If I pull into work and let the car sit for 20 min and then take it for a drive it all goes back to normal. But this time the problem doesn't take an hour to resurface it takes like 10 min.

I am sure it is a heat problem because a couple of weeks ago my fan relay burned out and I got the exact same symptoms within 10 minutes of driving first thing in the morning. And in that case the temp gauge as getting a little over normal heat.

I bought a nismo thermostat 149deg, I am going to put it in I am just afraid that it will just banaid the problem.

I have a DYNO tuning session on the 17th with my new GT25R so I am trying to get my swap to run perfect.

MY friend thought it might be the O2 since they run off of heat, but I am not sure. Apparently it is good practice to change the O2 when you swap the motor.

[Nismo_Freak]

02 doesn't affect WOT.

Temp Gauge (if stock) is worthless, you can gain 20 degs. of coolant temp and the ECU will cut out a few degrees of timing, but the gauge won't budge.

Basically I would look to increase flow through your radiator, you can do this with a nice $15 trip to Home Depot.

More importantly I would address your coolant. Replace the coolant you have now with a 70/30 mix (more water than coolant).

The Nismo thermo will just delay how long it takes for the motor to begin to warm up.

Those simple chores should lower cruising temps a solid 5-10 degrees.

Make sure you bleed the system of airbubbles when you open the coolant system.

[Nismo_Freak]

Oh and do you want your name changed to something else? LOL.

[Luke]

Have you tried replacing your Coolant Temperature Sensor? Go to a Nissan dealer and pick up one for a 91-94 240sx (KA24DE). A bad one won't cause an SR to fall on it's face, but it doesn't run as well either. It helped me with some inconsistent power at varying temps. on mine.

EDIT: I don't have the part # here with me at work, but it was only $15.00. It wouldn't hurt to replace no matter what.
Modified by Luke at 9:49 AM 6/8/2005

[kota2240]

you intake temps are probably getting to hot. I had the same problem as you. I moved my intake farther away from the motor and i took my electric fan off and installed the pulley fan with the shroud. I think this helps keep the intake from sucking in hot air. This ususaully happend to me when i was in stop and go traffic, but once i got up to speed on the highway everything was good. Now I have no problems at all. I sat in 30min traffic the other day in 90 deg with lots of humidity and it ran great with no loss of power.

[kota2240]

also try what everone else has mentioned, more water in radiator and change the coolant temp sensor.

[ka24det-power]

- When I did the swap I drained all the coolant / water and used that "Ice Water" product. I used it in my friends eclipse a year ago and it dropped the operating temp 15deg.

- I would love to change my name, I am SR for life now. Well maybe and RB if I win the lotto.

- What is this hardware trick that everyone is referring too.

[spider_slayer]

kota2240 - i am doubting that your intake had anything to do with your temp problem, remember that the air that is sucked in passes through a 1000 degree turbo charger. replacing the fan shroud probally did the trick.

ka24det - try and find a fan shroud if you don't have one, this can help alot