Throttle body heater pipes

[pablo_vr6 0]

noticed that the TB on my VR6 has 2 heater pipes going to it. are these always passing hot water? If so are they a drain on hp?

 

ta

-pablo

[PhatVR6 0]

yes, they are only any use in cold climates.

 

disconnect them from the TB and jointhem together. just leave the TB as it is, or even better, pump your washer bottle fluid through it to keep it cool!

[Kevin Bacon 5]

Given the throttle absorbs tonnes of heat from the manifold anyway, is it worth it?

[PhatVR6 0]

the throttle body has a heat sheild on it to stop it absorbing manifold heat (well, some of them do, not all of them).

 

you think pumping 100C water through it helps matters? or course not. same as a cold air intake, PCV bypass and all that, they all go towards attaing a cold intake charge, which as you well know means more air, and more power.

 

Anything you do to keep that air cold will improve power and more importantly, throttle response.

 

I've already mentioned in other air filter threads how sluggish VR6's are with a cone filter in the engine bay. they hate hot air.

 

as for bolting on a supercharger with no intercooler or charge cooler or water injection :roll: well, you might as well stick a 500W hair dryer on there....

[Kevin Bacon 5]

Hmmmm..... when you put it like that..... might have to try that then. Also been meaning to sort a PCV bypass out for ages as I don't like oil getting in the inlet.

 

What I don't understand is why VW used a heated throttle body in the UK anyway. It doesn't get cold enough here for fuel icing and it's no use until the coolant is hot anyway, so kind of pointless. Unless....the coolant is there to take heat away from the throttle due to the heatsoak from the manifold? Bit like the water/oil heat exchanger?

[PhatVR6 0]

never mind the oil, have you felt the heat of the air coming out of the breather!! the oily air also lowers the RON rating of the fuel, or so I've been told, I can't prove that one though.

 

hmm, water at 90-100, intake air at about 25 say? I think it's to heat it up, not cool it....

[GarageQueen 0]

as for bolting on a supercharger with no intercooler or charge cooler or water injection :roll: well, you might as well stick a 500W hair dryer on there....

 

On a 15' C day, with a compressor efficiency of 72% at 6psi on an otherwise stock VR6 the compressor outlet temperature will be around 56' C.

 

With correct fuelling & timing it will provide sufficient airflow at 6000 RPM for an output of around 240bhp at the flywheel or 176KW. That's a 36KW or just over 25% increase over standard. A reasonable return on a 500W investment?

 

Suffice to say that without a creative rolling road or capacity increase, no N/A 2.9 12v VR6 can match that, regardless of the intake temperature.

[Kevin Bacon 5]

Welcome to the forum GarageQueen.

 

You certainly appear to know your stuff. Hope you stick around to share some knowledge :wink:

[Joe M 0]

Given the throttle absorbs tonnes of heat from the manifold anyway, is it worth it?

 

The manifold doesnt get that hot, more like lukewarm. Go for a hard drive then as soon as you stop pop the bonnet and feel it before it gets a chance to heatsoak with the car sitting still. Try it with the throttle body as well though with the coolent pipes attached and theres a good chance youll burn your hand.

[Kevin Bacon 5]

I'll put the coolant bypass next on the mod list then :wink:

[pablo_vr6 0]

we measured 56deg on the sensor and with a thermometer on the rolling road at idle.

 

thats pretty damn hot aint it?

[Joe M 0]

I measured mine with my hand as soon as I stopped in the pitlane at Knockhill. The airflow when the cars moving makes all the difference, especially if you have a grill with all the slats open.

After it had been sitting a few minutes it definately felt a lot hotter.

[Kevin Bacon 5]

Yeah it's the heatsoak sitting at idle that gets the inlet temperature up, but once on the move, the airflow inside and around the manifold cools things down again.

[craigowl 0]

Speaking as a beginner to the VR6 bits and pieces, where is the throttle body please, guys?

[Joe M 0]

If you follow the large black plastic pipe back from where the airfilter is its the first alloy section you get to, before the inlet manifold.

 

ps, disks going in the post first thing.

[Kevin Bacon 5]

Follow the intake tube from the airbox and where it ends is the throttle body :wink:

 

You'll see the throttle cable connected to it and a couple of springs, plus the afore mentioned coolant hoses.

[craigowl 0]

Thanks Joe and kevhaywire, I'm with you.

[PhatVR6 0]

as for bolting on a supercharger with no intercooler or charge cooler or water injection :roll: well, you might as well stick a 500W hair dryer on there....

 

On a 15' C day, with a compressor efficiency of 72% at 6psi on an otherwise stock VR6 the compressor outlet temperature will be around 56' C.

 

With correct fuelling & timing it will provide sufficient airflow at 6000 RPM for an output of around 240bhp at the flywheel or 176KW. That's a 36KW or just over 25% increase over standard. A reasonable return on a 500W investment?

 

Suffice to say that without a creative rolling road or capacity increase, no N/A 2.9 12v VR6 can match that, regardless of the intake temperature.

 

wooo, 50bhp for £3500, no thanks.

[Storm 0]

Before I go ripping these out can anyone tell me why did VW put the pipes there in the first place?

[PhatVR6 0]

to stop the throttle body icing in cold weather.

 

you can always put them back on in the winter if you're paranoid about it.

 

I bypassed mine last night.

[pablo_vr6 0]

any difference?

[PhatVR6 0]

dunno, I haven't driven it yet! and seeing as I fitted the schrick VGI and a PCV filter I doubt I'll notice if it's made much difference as all the effect will be attributed to the vgi.

 

but I can tell you that the fastest NA mk3 VR6 in the world runs iced water through his........

[dan 0]

Am I right in thinking, all we need to do the by-pass is a little hose insert (mm size?) & two hose clips? Do we need to plug the holes in the TB?

 

Phat, did you say earlier that we could run water through the TB from the window wash resevior. If so whats required to do that?

[pablo_vr6 0]

yeah sounds about right.

[PhatVR6 0]

bang on, just join them together. it's neater if you shorten them too, but that means you'll have to keep hold of the bit you cut off if you ever want to put it back on.

 

you can leave the throttle body as it is, it won't do any harm being left like that.

 

As for the washer bottle, I guess you could just rig up another pump (a washer pump probably would be able to cope with the duty cycle). all it has to do is draw cold water out of the bottom of the reservoir and return it to the top. it'd save having to put loads of screenwash in anyway, at least it won't freeze!

 

People run charge coolers off the washer bottle, so I don't see why you couldn't run the TB off it too. dunno how long it would take before it all got hot though. I suppose you'd need a certain amount of fluid on there so that it'll naturally cool before it's pumped around again.