Hot Throttle bodies

[Steve P]

Evening gents,

I recently installed a Phoenix ex manifold and I've noticed that the throttle bodies are very hot. They must be around 50 to 60c just to hot to touch.

 

I dont recall being aware of how hot the throttle bodies were before so I dont know if this is acceptable or not.

 

Opinions / experiences welcome.

 

Thanks

Steve

[snowric]

my headers are wrapped all the way from the head to the exhaust under my seat.

 

Still pretty warm in there...

[Steve P]

Thanks for the response snowric.

 

I was just surprised at how hot they were. I'm going to measure the temperature later.

 

Steve

[Peter Cobbold]

Steve, That's very hot compared with what I recall of the original design of exhaust and cold air intake.

Are you using underbonnet air filters ?

 

Hot runners will help fuel evaporate, but will heat the air and reduce volumetric effciciency, hence power.

If the mixuture is heated to 60C is will loose about 14% of power compared with 20C ambient air.

http://resources.yesican-science.ca/SS_version1/ss/g08/fl/density.gif

Heat is the enemy of power, so its well worth doing all you can to get the manifold and mixture running cool.

 

Peter

[Steves_TR6]

I did some tests a couple of years ago, with a temp probe inside the air manifold, thats connected to the throttle bodies by the 6 rubber tubes.

 

In traffic it got up to 60c+ but as soon as the car was moving the temp dropped rapidly.

 

I am running an unwrapped 'sports' manifold of unknown origin, possibly racetorations or phoenix.

 

Car runs superbly, it does require some cranking if its parked when fully hot and left to stew

 

Steve

[GT6M]

was this wid engine idling for a while,

if so, it will mek,m v v hot.

 

I got an air temp probe in the Log, on the go, v light throttles, on a normal day

it reas about 30 degsC, floor the throttles for a while, it,ll drop to about 10 ish

 

leave it to idle for a while, it easily reaches 60-70 drgs

this why it were disconected at last spirint, as long idling effects power output

esp if the temp gauge is linked to ign retard and fuel reductionee.

 

good tip for ye, is to, { if yer cars got one } put the electric fan on yer rad,

as soon as ye think yer gonna be in any standing traffic,

the fan will help in shifting hot air, That is, if the hot air can get oot the engine bay

hard wurk if yer no got any vents in wings or bonnet

 

 

M

Edited September 22, 2016 by GT6M

[Steve P]

Evening gents,

So for the record I measured the skin temp on the side of the carbs and they were around 85C to 90C. Temp on the top of the throttle body near to the connection with the head was around 75C. I was very surprised.

 

Any how car seems to run fine. (at the moment)

 

Steve

[Steve P]

Evening gents,

Another update for the record. I had some exhaust wrap lying around, enough to wrap the the down tubes for about 8" to 10".

 

Result was a 15deg drop in skin tempo of the throttle bodies to 75 to 65degC

 

Steve

[TriumphV8]

There is a difference between carbs and PI throttle bodies.

Post 7 seems to refer to carbs, they are heated by water

passing the manifolds and the water has 80 degrees.

 

The PI can be kept cooler and has no water passage.

So other "Tricks" can be employed to bring temp down

it does no harm like in carbs where a lot of fuel would

condense on cold manifold walls.

 

PI has a fuel spray close to the inlet valve, already directed

not to hit the manifold more than necessary.

So I would wrap the exhaust manifold, avoid inlet manifold touching

the exhaust flange and look that the fasteners touch the manifold

only at the small points they are designed for.

 

I fear the result is more academic than really an improvement.

EFI does "see" the air inlet temp and correct the mixture so

also from that view the engine suffers only from a little rised

inlet temp and looses some power but as the air intake is in

the front (better than with the carbs) the inlet air temp, like

already mentioned, drops quickly when car is driving........