Turbo_Steve

Is the heater pipe in the bottom of the throttle-body + ISCV thermostatically controlled?

Has anyone removed this and found their throttle body iced up?

I actually felt how warm the throttle body was in relation to the rest of the inlet system yesterday, and concluded this must simply be heating the charge just after it has been intercooled: surely not a good idea!

UkLegacyT

take it off mate, you can get little metal connectors to join the hoses up rather than onto the throttle.

had mine off ages, and all previous cars, they just heat up the charge.

ian

iain atkins

Also removed mine as well, with no ill effects whatsoever

Turbo_Steve

Groovy...thanks guys. Off to the plumbing store I go..I go.......

BruceWarne

Please, could someone explain this to me? What part are we talking about? What does it do? How do I identify & replace it...
I'm totally in the dark here.

Thanks!

Turbo_Steve

Look at your Intercooler. Then look at your inlet-manifold. In between is your throttle control, which is basically a chunk of metal shaped like a pipe, with a butterfly flap inside.

In extreme conditions this part can ice up, locking the throttle open. This is very unlikely to happen, especially after the charge has been through the turbo.

On the bottom of the throttle body there is a pipe conneced to the hot water of the engine, that is designed to heat the throttle body and prevent said icing.

Unfortunately heating up the charge (after you just put all that effort into cooling it down with your intercooler) is verging on pointless. Far better to remove the pipe and keep the inlet temp down.

You will have to take your intercooler off to get at the heating plumbing, but I am guessing you might get as much as 2bhp from this mod.

Don't do it until the engine is stone cold!!!!!!
Just get a bit of pipe and connect the two rubber ones to each other. Hmm....maybe I should post something in projects.....

BruceWarne

Thanks!

STE.W.

Steve, at the wekend when changing the temperature sensor to the ecu for a new one, I did the "charge warmer" mod on the throttle body side. Thanks for the above descriptions.

Please could you advise if you did the ISCV one.

I'm going to show my lack of knowledge here by asking what is probs a simple question that everyone but me know the answer to:

What is an "ISCV"??

Is it the thing next to the throttle body with a big grey plug on it? It goes into the plenum chamber thingy.

This also had two pipes (in and out) with hot water fed through them.

Just wondering as I could do this mod if its worth while and wont knack summat.

Thanks in advance.

Ste.

Turbo_Steve

Taking it off won't "knack nuffink" unless you start the car in sub-zero conditions a lot. As very little air is taken through the ISCV (Idle Speed Control Valve) when driving, it's only when stationary, I decided to leave mine well alone.

And yes, it IS the big grey thing!

The only reason these are heated is to stop them icing up when cold moist air is sucked into the air intake.
As any air that reaches the throttle body will have been through the turbo, this seems unlikely to me.
The Idle Valve takes it's air from directly after the filter, so is more likely to suffer. I left it be: it doesn't feel like it conducts that much heat to the inlet manifold, esp compared to what it picks up from the engine block.

I have to be honest: I haven't disconnected my throttle body yet. This weekend is going to be "intercooler off" weekend and will do it then.

STE.W.

No probs, thanks for the answer.

I took the intercooler off myne on Sunday when I changed the lambda sensor and water temp sensor. I also had a water leak from the small pipe fitted to the ressy underneath the cooler.

Lots of cuts, grazes and bruises later all jobs completed including the charge warmer mod for good measure.

The neighbours also learned a few new words whilst they were having their barby Q within earshot of above maintenance programme!!!

Its amazing what you can get house hold copper rad pipe to fit to on cars eh!!

I'll leave the Idle speed water pipes alone I think.

Thanks again.

Ste.W.





[Edited by STE.W. - 4/29/2003 9:59:54 AM]

MACCAMY99

Has anyone measured the charge air temperature coming out of the intercooler? If its hot (ie. >70deg C) there will be little heating effect from the water system anyway at normal operating temperatures.
The consequence of having the throttle jam open sounds a bit scary !

Turbo_Steve

Throttle body won't jam after air has been through turbo and intercooler etc etc....VERY unlikely. And if the throttle jams, you just put the clutch in.

And coolant runs at pressure, so it will be about 120degrees C (at a guess) and you want as little heat as possible in your inlet charge.

submannz

It would be very unlikey for it to freeze up espesially when the car is up to temp.

The system is just a part of the pollution control to ensure all the fuel is burnt when entering the combustion chamber.

harvey

iTrader: (48)

The throttle body temp on my car (FMIC) in the cruise is around ambient or a couple of degrees above. Prior to the FMIC it was typically 12+ in similar circumstances. On hard road work now it could go to amb+ 6-12deg C.When parked hot the temp can rise to 40-60 Deg(total temp)quite easily but this comes down to normal in a few minutes once underway with reasonable forward movement.
Any benefit in removing the water supply to the T/B is probably immeasurable.
On aero engines with carbs it is possible to pass warm air through the carb to prevent carb icing but this is not an issue on fuel injected engines.

Turbo_Steve

So parked up waiting to do say...ohhh....a 1/4 mile run, removing the heater will stop the throttle body being hot for the run.
Which is what I was trying to achieve.


I agree, the difference is measurable in millions of a bhp under normal driving conditions, but I don't want to be running my nice cold charge (and I have a charge cooler, not an intercool, so no heatsoak for me) through a hot bit of pipe prior to the cylinders.
If I have been parked up with my engine running (to get it up to temp etc) and then blat the nuts off it, I am losing power cos of my hot throttle body.

dhorwich

on a 1/4 mile blast surely as soon as you get moving and on full boost the air will not have enough time to be heated by the throttle body that has heated up while waiting to run..???? its being forced in a what ever PSI you are running and this will happen pretty fast..???

Dan

Turbo_Steve

Hmm...hadn't considered the flow rate.
But then the intercooler is pretty tiny, and the rate of heat exchange through that is considerable.

I wouldn't underestimate how quickly air will take on heat.

I mean, the heating element in a hairdrier is only 150 or so degrees and that gets the air HOT,

harvey

iTrader: (48)

Dan is absolutely correct. You would not use a hair drier element to heat up a whole room.
The velocity of air over the T.B.is so fast that any temp pick up is virtually nil.
You could ask Pavlo to calculate it but he might tell you it is a pointless exercise.
Do it by all means because I work on the principle of many a mickle maks a muckle. Another possible benefit would be a reduction in heat transfer to the I.M. but again not measurable IMHO.

Turbo_Steve

Ok ok..I won't trouble Pavlo with something so trivial.

But I'll plough on & do it because heat is the enemy. Besides, it'll stop me burning my fingers so often! lol

Must admit I hadn't considered the sheer volume of air being flowed by the throttle body on boost.