Hot ait intake

DanW · Post by **DanW** » Mon Mar 08, 2004 8:39 pm

Hows fittings with these things?
Can I do it without much trouble?

Phoenix · Post by **Phoenix** » Tue Mar 09, 2004 1:03 am

lol try the blue and the black sensor, thats what i've done on my MkII and its worked

Â£3 for both from local scrappy, or five finger discount if you can get the chance, just clean them up with a soft wire brush, mine came out shiny as new and work fine now

hardhitter · Post by **hardhitter** » Tue Mar 09, 2004 7:29 pm

The whole point of replacing the temp sensors, is to put new ones on that you know are right.
Why go to a scrappy and buy second hand sensors, that might not work and not give correct readings ?
It's a bit pointless when you can get them brand new from VW or Vagparts for Â£8 for the black and Â£11 for the blue one. The mk 3 heavily relies on the blue temp sensor to give accurate readings to the ecu.

Phoenix · Post by **Phoenix** » Thu Mar 11, 2004 7:31 pm

yeh but if its not working to start with and you can five finger discount on them then its worth a try then its cost you nothing

dub envy · Post by **dub envy** » Fri Mar 12, 2004 5:48 pm

shut up you idiot.

Phoenix · Post by **Phoenix** » Sun Mar 14, 2004 12:58 am

lol just my suggestion and it worked on mine, just offering my advice

Tahrey1043 · Post by **Tahrey1043** » Wed Mar 17, 2004 2:39 am

All I can say on this subject is a piece of supporting evidence... my own Polo quite often will not nose above 70 degrees (or much beyond it) on a drive, oddly not even with the throttles locked open (must be all the extra ventilation that comes with moving quickly?). Been getting used to it. The hot air pipe *is* slightly knackered, but present and should have some effect...

Did, however, surprise me recently by getting up to 95 just long enough for the fan to kick in when crawling thru the goddamn traffic in Stoke last week though, so I know the temp guage isn't shot! (It doesnt even get that warm when sitting idling parked for a good half hour, just to give you a measure of the pure evil inherent in that city

- I even had the motor off for maybe a full minute on several occasions)

And as for not needing the hot air pipe on modern machines - tell it to my past self desperately trying to get the f**xer to start in the first severe snowy/icy snap I endured with it without any cold-start mix. I do beleive either the fuel pump or the injector froze up (or the plugs iced over?!) and so knackered any chance of getting it running for a good ten minutes or more, while i pulled out every trick in the book to warm up the essentials. Hot air pipe a definate neccessity there (assuming it was the injector anyway!) during the later stages and after starting so that I wouldnt have to stop every quarter mile to pop the bonnet and filter lid to rub a warm finger over the nozzle! (ignition OFF of course!) *cue old-timers stories of cars stalling out on the motorway in winter when carbs iced up*

LogIK · Post by **LogIK** » Wed Mar 17, 2004 12:39 pm

So how easy are these blue temp sensors to replace, as I am thinking of doing it? Just wana know wots involved and whether its worth tinkering with.

optima21 · Post by **optima21** » Wed Mar 17, 2004 12:41 pm

Aye I'm one of the old times who has had his mk2 freezing up on the motorway, and its due to deign of the induction system. As the warm air feed on the mk2 and mk3's work on both temperhature and vacuum, so when you put your foot down and the vacuum in the inlet manifold reduces, the car will suck cold air instead of warm air. I'm running my mk2 with a permanant hot air feed, and it seems to have cured the problem with carb icing, although I still have a can of de-icer in the car to give the jets in the carb a blast just in case I should need to.

It is my opinion on the mk3 Gt and Nz's thats its better to retain the original induction system and enlarge the air intake in the grill and fit a sports air filter, as the air is forced through the filter, with the cold air feeds that people use, they dont enclose the filter completely and so any ram effect is lost.

While it might be said that there is more oxygen in colder air, its alos true that there is also more oxygen in air thats under slight pressure, than under slight vacuum, so just think about that guys, you can get a ram effect with modifying the intake to the standard system, but people dont do that with induction kits and cold air feeds.

Also with the cold air feeds, what do you use? convoluted aluminium tubing? if so just think about the drag on the walls inside due to the lumps, which will reduce ammount of cold air that gets to the engine. I think its probably more likely that you'll geta smoother airflow thorugh the standard system with its smooth (ish) internal walls.

oh and I've probably said that my GT runs about 70C as standard, and I think thats gotta be an advantage for a performance engine, as the same engine will generate more power than the same engine running at 90C.

amstrange1 · Post by **amstrange1** » Wed Mar 17, 2004 12:47 pm

LogIK wrote:So how easy are these blue temp sensors to replace, as I am thinking of doing it? Just wana know wots involved and whether its worth tinkering with.

Piece of p*** to do - 30 second job normally. Unplug the wiring connector, pull out the clip holding the sender in and fit the new sender.

amstrange1 · Post by **amstrange1** » Wed Mar 17, 2004 12:54 pm

optima21 wrote:oh and I've probably said that my GT runs about 70C as standard, and I think thats gotta be an advantage for a performance engine, as the same engine will generate more power than the same engine running at 90C.

I know what you're saying Dom, but the fuel injection system will surely have been setup and mapped to run at its normal running temp of 90C? I've fitted a new thermostat to the GT engine that's temporarily replacing the G40 for that reason.

Not only that, surely the engine internals are designed to perform best at a certain temperature? I know when my G40's rebuilt with forged pistons (I know this is an extreme example) it'll knock when cold (like TVRs do) until they warm up and expand. I think Beavis said they can also use a bit of oil when cold too, as rings and pistons haven't expanded. The G40 will also get a new thermostat, but also a 'statted oil cooler - the aim is to keep the oil temperature as constant as possible.

DanW · Post by **DanW** » Wed Mar 17, 2004 3:08 pm

optima21 wrote: It is my opinion on the mk3 Gt and Nz's thats its better to retain the original induction system and enlarge the air intake in the grill and fit a sports air filter

So would it be better to see if I could add another feed to the cold air intake? Or fit lots of small ones in there, I've noticed when I get the wirring noise of a lot of cold air rushing into the engine at the front I still get quite a bit of power.

optima21 · Post by **optima21** » Wed Mar 17, 2004 3:27 pm

DanW wrote: So would it be better to see if I could add another feed to the cold air intake? Or fit lots of small ones in there, I've noticed when I get the wirring noise of a lot of cold air rushing into the engine at the front I still get quite a bit of power.

I'm not going that route, all I'm doing is opening up the holes in the grill so its teh full size of the air intakes and also cutting the plate which mounts the air feed to the grill so thats bigger. I think the biggest restriction on the intake system as standard is the Airflow meter, but I'll be modifying the airfilter cover top to use one from a golf.

DanW · Post by **DanW** » Wed Mar 17, 2004 10:17 pm

optima21 wrote: I'm not going that route, all I'm doing is opening up the holes in the grill so its teh full size of the air intakes and also cutting the plate which mounts the air feed to the grill so thats bigger. I think the biggest restriction on the intake system as standard is the Airflow meter, but I'll be modifying the airfilter cover top to use one from a golf.

That could be interesting, it is hard to fit a differnt air flow meter?
Anotehr question, isn't the engine designed to run with a certain amount of air? Therefore increasing the air flow isn't going to do much just make the engine rich...Unless I've got the wrong end of the stick

amstrange1 · Post by **amstrange1** » Wed Mar 17, 2004 11:05 pm

DanW wrote:That could be interesting, it is hard to fit a differnt air flow meter?
Anotehr question, isn't the engine designed to run with a certain amount of air? Therefore increasing the air flow isn't going to do much just make the engine rich...Unless I've got the wrong end of the stick

The airflow meter from an 8v Golf Mk2 GTI with Digifant injection is a straight swap, but won't fit the Polo airbox. Apparently the ECU is capable of adjusting itself automatically to account for the extra airflow.