so the other day i was replacing the heater hoses and i thought to myself, other than in cold weather why does the intake need to have coolant fed threw it?
It makes since that cooler air makes better power and if you just bypass the intake and run a hose off the thermostat housing to the heater core would keep the intake temps cooler without 200 degree water passing each runner. But then i pondered some more and thought that the coolant could run threw the intake for a couple reasons:
1 the exhaust manifold is right under the intake and the coolant is actually cooling the intake from the heat off the exhaust
2 there are water jackets shared with the head and intake
3 the coolant temp sensor is in the manifold.
Now i came and posted this here to get some more input and see if bypassing the intake is or isn't a good idea because if it works it would be simple to do and the cooler denser air should make the engine run better.
Just keep going till it sounds expensive
From my experience with intercooled turbo charged cars....it wont help that much, short of throwing an intercooler in front of the engine, it wont provide enough cooling to make a noticalbe difference. But thats just my experience but thats with 2.0L with dinner plate turbos pushing over 300bhp. It might make a difference in a jeep since the levels are not nearly as extreme.
True but with boosted engines the compression of the air creates heat ( I'm sure you know) thus the need for the intercooler. But I actually got this idea from my friend who told me its pretty common thing to do on Hondas. And he got the idea from his prelude forum lol
Just keep going till it sounds expensive
Running my saab at 16psi created alot of heat, enough to make me upgrade to a bigger waste gate to help get out all the pressure but I really dont see it helping much here. Maybe this will be my experiment tomorrow night at the garage while I'm doing an oil change on my dad's truck.
Well one thing is in the winter time in fact any time when the temperature is about 55 or below it keeps the moisture in the air from freezing. In longer runners on the front and back you would get a imbalance of fuel mixture to the cylinders. Now if someone could make a intake that had closer balance in length for the runners then you would not need them( like 225ci slant 6 engine have.
A 89 yj with a 4.0 aw4 sye out of an 92xj. Now the hard part is done time to get it up in the air just a bit. Working on 8.8 with 3.73 and lsd for the rear. and new D30 hp with 3.73 .
For those who have not figured this out I'm old school but can handle the new too.
For race type applications, this is a good idea. But for a street engine that will be turning under 4,000 RPMS all the time, it is a horrible idea. You need the manifold heated for proper fuel evaporation, and proper air/fuel mixture throughout the intake.
418 miles on 19 gallons of gas. Can't beat the BBD !
If it was race only taking the heat out of the intake would certainly cool the charge and help power in the upper RPMs.The high mixture velocity would maintain good distribution and help to vaporize the fuel .BUT, At slower rpms seen by daily drivers, the use of manifold heat ensures that the fuel is vaporized. If heat is not used, the engine will run rough at slower speeds and distribution problems will become an issue. Aside from these points a lot of the emission systems are reliant on this heat as well.
Your limited slip differential sucks.
The heat is there to boil off the fuel that falls out of suspension and pools on the bottom of your intake. This is why a carb needs to run a choke when cold. Because the fuel falls out of suspension or doesn't atomize properly and puddles on the floor of your intake and the correct a/f mix does not make it's way down each runner. So to compensate for this you need to throw more fuel at it to get an acceptable a/f mix for those first few minutes. V8 engine use either exhaust heat or coolant to heat the intake manifold, however by design a V8 intake manifold will naturally be warmed up by the rest of the engine so that eventually it will get up to an acceptable temp however an inline engine with the intake hanging off the side of the motor will stay much more cool, especially when it's colder outside.
So yes, you will make more top end power if you bypass the coolant, however during normal driving throttle response, driveability and warm-up time will all be worsened. It will also probably want to bog a bit during normal driving.
Also, I would think it was there to keep the intake cool. With the exhaust right underneath, I would think it will see some very hot heat. Also heat transfered from the head to the intake will add some heat. So with a constant 190 to 200 coolent you keep the intake cool but hot enought to keep the fuel atomize.
There is also a warm up 12V heater in the bottom of the intake. I beleive this only works when cold.
90 YJ, 4.2 with 2150 carb 4.0 Head and headers, Nutter with TFI and MSD. 1" BL, 2.5" spring lift, 33", Goodrich KM Mud Tires. Dana 30 w Aussie, Ford 8.8 w LS. 9000lb HF Winch.