I have the 4.2 N/A the throttle body is in the front of the motor. There are 2 coolant hoses that connect under the throttle body. One of the hoses was weak so I ordered a new one. The hose connects on the TB and runs down the fron of the motor. I have looked everywhere and I cannot find where the other end of this hose connects too.

Does it connect to the water pump? I just want a feel for what I am getting into before I tear the whole front of the motor down.

 

Sorry don't know - but it'll be in JTIS and/or JEPC (I hope!)

 

I looked all over both of them and could find it anywhere. Maybe I just ain't look in the right place

 

achysklic, you can disconnect this hose from the throttle body and connect it to the return line as a means to bypass heating the TB. This will likely give you 5+ hp. STR guys have had this performed, earning nearly 10 hp. I'm having the same performed when the mechanic removes the blower for a rebuild/port.

 

You know it is there for a reason. Not a good idea to remove it in cold climates.

 

Yep Bob. The reason to warm the TB is to more quickly lean the mixture from start-up to idle. achysklic, do you intend to drive yer cat during the winter?

 

Throttle Icing: Understanding the Icing Mechanism and Effects of Various Throttle Features
Auto Tech: Throttle Icing - Autos.ca

 

Throttle iceing too? Dang!

 

You could try a couple valves and turn them on in the winter. I haven't looked but is there a thermostatic valve in there already?

 

I like the idea of using a valve to allow warm coolant to warm the TB for the winter. Very clever Bob.

 

Thanks but I'm just borrowing from some of my early Italian cars that turn the water flow for the heater on and off with an ordinary facet valve under the dash.

You might want to research this a bit though. It may be that even if it's OK to bypass the throttle body you still might need that flow route for proper overall engine cooling. I have no idea but it's something to consider. If so, then that would be a touch more complicated to plumb but not impossible.

 

Cooant heating for throttle body or inlet manifold is there to prevent icing which you'll get on very high throughputs as the petrol is partially atomized, partially vaporized from the injectors. It also assists in further vaporizing the atomized parts of the charge, as does hot pistons and cylinders. Disabling this heating will bring trouble, especially if you use a lot of power.
The mpg figure will also suffer. On this one I'm sure Jag. designers are 100% right.
Leedsman.

 

This hose is driving me nuts, I took the air box out and removed the throttle body. It looks like the end of the hose disappears under the intake manifold. Surely I don't have to remove the intake manifold to get to this hose? Help needed please!

 

10 horsepower? Sounds a bit optimistic. My E36 BMW M3 got a 13 hp increase at
the wheels (dyno) with a cat-back exhaust, reflashed computor, and cold-air intake.
You may also get some driveability issues.

 

achysklic and matty, the coolant hose leaving the TB runs under the intake manifold (the dreaded STR leaking hose) then re-enters the coolant system. Mafioso bypassed this by conjoining the coolant lines to the TB. He says his STR runs fine and feels slightly more powerful; albeit a slight drop in mpg's that he gained from his "Mafioso" air intake elbow. Matty, the BMW M3 is naturally aspirated whilst the STR; blown. Mafioso recorded a 13 hp @ 7 lb/ft torque increase on his STR with his "Mafio" air intake elbow alone. It's expected that this mod will reflect a lower hp gain on a n/a motor. All the mods you mentioned plus a 3 lb. pulley and low temp. thermostat gave an est. 50+ hp to my STR. An intercooler chiller and an ECU tune will likely allow another 35+ hp. My modded STR runs ballistic on a cool day but falls off when temps climb over 75 degrees. I mentioned a possible 5 hp increase for a n/a motor and a 10 hp for a blown motor. I don't know HP ? till this alteration is dynoed. Mafioso lives in Texas. He'll likely not come across extreme cold conditions, on the other hand I live in NY. I don't drive her during the winter months and wouldn't with a bypassed TB...unless Bob's on/off valve is incorporated.

 

OK, probably worth a try. I guess it's something that you can reverse easily if it doesn't work out. Let us know the results.

 

10-4 on that matty. When the blower is sent out for rebuild/port the time is ripe to fiddle with the TB cooling lines...on/off valve.

 

I bypassed the Tb line on my 5.0 stang way back in the day. Had it like that for years as did a lot of the 5.0 guys. it just took a little longer for the cold start program to switch off. Not sure how it would affect the str? I would not expect much from it power wise if at all.

 

qwikcat, thanks for helping me decide not to by pass TB coolant circuit.

 

No prob I get the idea behind it. Just on the STR motor the slight amount of heat your saving there your picking it back up from the blower and intercooler heat. On an NA maybe but I don't see any power to be had on the STR. The iat will be the same if you want to lower that look into the chiller or water inj.