throttle body coolant bypass

[smidge]

never gets below 10degrees here so i'm not worried about anything freezing

if i'm not mistaken it goes from the turbo, through the edge of the intake manifold then out and into the throttle body

its like a coolant maze!

so... who's done it?

 

[frank]

it work fine on a k11 smidge (tho i have to toe-n-heal for the 1st mile with no coldstart fast idle)

 

[smidge]

thanks frank, i did it on my subaru's and it didn't cause me any problems

there are more days above 20degrees than below and its in the heat where the ST struggles


i just put in 7 heat range plugs and its a little stuttery on idle but fine once you get going

 

[Alienfish360]

Remember that Carb Icing can and does occur in temperatures quite a bit ABOVE freezing temperatures, it only requires moist air.

 

[frank]

Remember that Carb Icing can and does occur in temperatures quite a bit ABOVE freezing temperatures, it only requires moist air.

mine got though last winter no probs and whats the point in having a cold air intake, or intercooler, then waterheating the throttlebody ?

 

[Alienfish360]

The icing is more of a risk in the venturi, and the vacuum further compounds it. Carb Icing is a serious risk to aircraft, however, the risk of losing power at a few thousand feet is there in a car, they still suffer from carb icing in humid conditions (not cold)

However, a carb is more prone to icing than a throttle body.

 

[Baz]

Did you gain anything from byassing it?
I was thinking off doing it just hav'nt got around to it

 

[frank]

Did you gain anything from byassing it?
I was thinking off doing it just hav'nt got around to it

i,ve no idea baz :wasntme:, it just seems daft to warm the t/b up, and it wont ice up when the injectors are so far downstream from the t/b eh ( and my lpg is megga cold when it comes out of the nozzle, but its been fine :grinning

 

[smidge]

considering the temperatures here get pretty warm, and i've spent all this time installing a front mount intercooler it seems a bit pointless to warm the air up a bit again before it goes down the motors gut

i wouldn't do it on a car i planned to take the snow etc

thanks for the replies guys! very useful

 

[Alienfish360]

considering the temperatures here get pretty warm, and i've spent all this time installing a front mount intercooler it seems a bit pointless to warm the air up a bit again before it goes down the motors gut

i wouldn't do it on a car i planned to take the snow etc

thanks for the replies guys! very useful

The venturi effect + vacuum CAN and DOES cause icing above freezing. I have PERSONALLY seen carb icing occur at +25c.

 

[Baz]

The venturi effect + vacuum CAN and DOES cause icing above freezing. I have PERSONALLY seen carb icing occur at +25c.

Doubt it on a st in austrailia man, hot running engine in a hot country

 

[frank]

The venturi effect + vacuum CAN and DOES cause icing above freezing. I have PERSONALLY seen carb icing occur at +25c.

my understanding is that its the evaporation of the fuel that causes icing not the venturi :glare:
and st,s are injected not carbed

 

[Alienfish360]

Doubt it on a st in austrailia man, hot running engine in a hot country

Ambient temperature has very little effect on carb icing.

my understanding is that its the everporation of the fuel that causes icing not the venturi :glare:
and st,s are injected not carbed

I didn't know they was injected, the risk isn't anywhere near as great.

There are various contributory factors to carb icing, the following is a list of those factors:

Outside Air Temperature of 30Celsiuse
Adiabatic Cooling in the Venturi as the induction air expands as it passes through
Fuel Varporising abosorbing any latent heat.

It's possible for this to drop from 30celsius to below Zero, and if the air is moist you will get Ice.

The risk is also more so at partially closed throttle as the partially closed butterfly enhances the venturi cooling effect.

The above is the reason that ALL carb'd aircraft have Carb Heat, and why we always regulary turn carb heat to hot during a cruise and during descent and landing, as the partial throttle makes icing a serious risk, on the ground it's a loss of performance, in the air it's a little more serious, and why Carb Icing is such a major topic even on the PPL.

So with a Carb, you can encounter icing even in the middle of Summer, so if you've got a carb, leave the warm coolant hoses there.

 

[Baz]

Ah right, good bit of info there. . .interesting to say the least.

Cant believe you though the st was running a carb:wasntme:

 

[Ed]

lol @ phills totally irrelevent but correct posts (since the ST is inj)...

Bottom line is ST is fine with a TP coolent bypass. But you may find you have to reset the idle RPM. Thing is you wont block it off entirely as its fed through the inlet manifold casting. This idealy should be blocked off too.