4dscPat

Dont feed the trolls!

nismobaron

Okay, seeing as you want someone to hold your hand & figure everything out for you, just go to my cardomain page - the mod you want to do is really easy

http://www.cardomain.com/memberpage/495309/5

This was so easy - you shoulda got off your butt & played around yourself, instead of wasting everyone's time with stinking ford cobra's...

PS: Ford stands for...

Fix
Or
Repair
Daily

or in the UK ('cause they used to be really crappy...)

Found
On
Rubbish
Dump

5 ltr. beater

It's not exactly that I want someone to hold my hand; but messing with the ECU is just simply asking for trouble. TRUST ME, i know. Making the wrong mistakes has cost me too much money in the past when I used to perform "custom" work on my old LS1; and wasting everyone's time with Cobra's? I'm just explaining to internetautomar why I want an 03 Cobra since he so bluntly told me to be ashamed of myself for wanting one.
My point is simple; 03 Cobra's are today the fastest production car for under 30K and that can be putting out 500+rwhp with fairly cheap and simple mods, period.
Trust me, besides being a Maxima fanatic; i'm a die hard chevy fan; but the 03 Cobra is just too good of a car to pass up.

nismobaron

Hope the switch info helps you out BTW: I used a piece of aluminum for the switch bracket that I cut down (one of those crappy aluminum mounting strips that cheap car radios come with).
Shame you guys didn't get the Skyline GTR - for a 2.6 liter straight six it'd def give the cobra a run for it's money in a straight line & kick butt on a race course - with simple turbo, injector & ecu upgrades you can pull over 450 rwhp.

Personally, I'm not a fan of any particular make or model - too many people get tunnel vision when they're die-hard fans of one brand. Don't like or will ever own a German car (design is too teutonic for me), but respect the engineering that goes into them.
Prefer Nissans to other Jap cars (my 9th Nissan to date...) because most are easy to fix, parts are cheap & easy to get, well built, reliable & no-one wants to steal them, so the insurance isn't too high! (Jap cars are predominant in NZ, followed by Aussie GM Holden, Ford & Mitsubishi, Euros & some US cars & trucks).

Understand what you're saying about screwing up the ECU - it just bugs me that some people just want to bolt stuff on or expect others to give the answers without experimenting a little first. If you're not sure about any electronics, either get a book or find the info on the net first.

chchmax

hey, nismobaron, it seems that your switch just bridges the gap between the existing wire... shouldn't one end of the switch go to an earth or something? Sorry if i just don't get it, but it seems that you just cut a wire, and put a switch in between the 2 cut pieces... which wouldn't change anything except the ability to stop the fans from turning on altogether?

nismobaron

If you unhook the connector from the sensor, the fans kick in. This is because the ecu sends a current to the sensor and meaasures how much voltage it gets back. As the coolant gets warmer, the resistance in sensor increases, decreasing the voltage going back to the ecu. Once the coolant gets hot enough, the resistance effectively cuts off the current flowing thru the sensor (the voltage actually drops to around 1.2v). The ecu determines that the coolant is too hot & turns the fans on. The coolant sensor is a switch - a more precise switch to what I've hooked up, but a switch all the same. All I'm doing is telling the ecu that no current is able to flow thru the sensor & fooling it to think the coolant temperature is too hot.
You could tap into the sensor wire & earth the other side of the switch (had to do that on a Pontiac Le Mans - wired a switch inside the cabin via the ecu because the relay had blown), but this is simpler & you're not having to rely on a good earth connection to fool the ecu.

I must stress that for normal applications, let the ecu do the thinking for you & don't worry about this mod as you can do more damage to the engine if you overcool it.

mtcookson

iTrader: (2)

how can you over cool it? i would think the engine would like to run cooler.

mtcookson

iTrader: (2)

how can you over cool it? i would think the engine would like to run cooler.

MrGone

iTrader: (30)

I wouldnt go below 160*. If the engine is too cold, it will cause more wear on the engine, its like why your not supposed to go WOT on a cold engine....


but I do anyway

nismobaron

Not at all - internal combustion engines need to operate within a certain temperature range for both efficiency & mechanical reasons, which is why they're fitted with cooling devices like thermostats, water pumps & radiators.

The pistons have oil control & compression rings which need to expand to provide a good seal.

If the internal temperature is too low, the rings don't seal against the cylinder wall properly, you'll get exhaust & intake blowby, poor compression & piston slap - not to mention worn cylinder walls as the oil that should reduce friction ends up in the combustion chamber so that the rings end up rubbing against the walls.

If the internal temperature gets too hot, the oil control rings get very soft & aren't able to scrape the excess oil off the cylinder walls, resulting in oil in the combustion chamber, which leads to burnt valves, fouled plugs, unburnt fuel in the exhaust system (not good for the O2 sensor or the cat), poor performance
- not to mention the oil getting too hot so it thins down, loses viscosity resulting in bearings running dry etc etc.
Get the picture?

That's why you should always install a thermostat & ensure it's within the manufacturer's operating specifications (i.e. 160 - 182 degrees).

mtcookson

iTrader: (2)

ahh, i see now. thanks for the info!

internetautomar

iTrader: (30)

BTW you were probably thinking of the coldest incoming air possible.
.02

mtcookson

iTrader: (2)

i think it was just how it always feels faster when cold. i think once the intake manifold and piping get hot getting cold air won't help as much since its going to heat back up in the intake and such. i could be wrong though.

internetautomar

iTrader: (30)

Isn't that why tou wrap your intake piping?
the heat transfer from the tube to the air isn't that much at the velocity the air is going into the engine

mtcookson

iTrader: (2)

hmm... might be interesting to test the temperatures of the air and see what it does. i'd probably have to test it on the gxe though since the air in my intake definitely gets hot due to the turbo. it seems with enough piping the air could be heated somewhat on the way to the engine.

Jeff92se

iTrader: (82)

I certainly agree that the engine and it's parts need to be within a certain operating temp in order to work properly. But as long as the engine parts are at operating temps, the incoming air could be as "cold" as possible. I mean not at freezing cold but as "cold" as you could reasonably get it. ie... around ambient vs ambient + 15degF (approx). Which might be the difference inbetween running a JWT HAI and a true CAI.

And Shawn, running WOT while the engine is cold is BAD. You ignjet! It's hard on the engine as block/pistons/rings/bearing etc.. all expand at different rates. If you are hard on the engine before it warms up properly, you are beating it to hell. The block is a big piece of metal and the piston is a smaller piece. I would assume the piston expands faster then the block. Now you have a big piece going up and down in a hole too small. Not good

eric93SE

iTrader: (1)

Its not such a good idea to put the switch between the sensor and the ecu. That way your telling the engine something is wrong and it turns on the fans. So the timming/fuel will get changed.

The best way to do it is to remotly energize the relay for the fans, nothing will burnout (as long as its wired correctly).

nismobaron

Yes & no.
Hooking the switch up like this won't fool you're ecu into failsafe mode, it just returns a 0v signal which the ecu interprets as the coolant temp being too high. Try just taking the sensor connector off - the fans come on, yet the check light stays off. The ecu may record this as a possible fault as 0v is being returned as opposed to approx 1.2v. If you wanted to get around this, find the coolant sensor feed wire at the ecu & hookup a double pole, single throw switch to it. On one side of the switch, wire the circuit as I've described. This side would be normally closed (or off). On the other side of the circuit, feed 1.2 - 1.5v to the ecu - thereby switching on the fans & ensuring the ecu doesn't think their's a fault with the sensor. You could probabaly power this side with a simple 1.5v AA battery...
Normally, you'd let the ecu do everything for you, but if you wanted to switch the fans on, you'd just flick the switch.

As for the application 5 ltr. beater wants, this is the simplest & easiest way - it wouldn't matter if the timing / fuel ratio did get changed as he's just idling at the drag strip, trying to cool down everything as much as possible.

I agree that the best way to activate the fans is to energize the relays but I think the switching signal is a negative voltage - you can't just hookup 12v! (could be wrong on this, though...).

Again, my caveat of letting the sensor & ecu do the work remains...

5 ltr. beater

The colder the air, the more dense it is with oxygen. More oxygen= more power. It's hotter during the day and that's why are cars feel more "sluggish" during the day time and they come alive more at night time. Altitude plays a big role in performance too. A car that runs the 1/4 mile at sea level will get a better time than a car that runs the 1/4 at 5000ft elevation. The higher you go, the less oxygen there is. That's physics 101 for you!