Your thoughts on throttle body bypassing...

[Pwnin O'Brien]

So I've been doing lots of research about a throttle body bypass. Some people say it's worth it, while others say it's dangerous. I can see how the hot throttle body can heat the upper intake manifold, thus warm the air a degree or two (probably not two tho). I can also see how the Venturi effect can cause ice to build up on the throttle body at startup (at least I think that's what causes the ice buildup). Lots of people that live in the north and have done the bypass say they've never had a problem. I've also seen dyno runs before and after a bypass and it showed an actual gain in HP.

Have any NICO members done a throttle body bypass? Any from the north?

What are your thoughts?

[alexf20c]

sounds about as beneficial as indexing your spark plugs.

[Pwnin O'Brien]

sounds about as beneficial as indexing your spark plugs.

Yeah, it's probably around the same gains as indexing spark plugs. I mean, it's about $4 in parts and about ten minutes of labor so even if there is no gain it's not a huge waste.

Also, I want to point out that it isn't our throttle body which is heated, it is the upper intake manifold which is heated which in turn heats the throttle body. So essentially, the entire intake manifold is getting heated by the coolant passing through it.
Modified by Pwnin O'Brien at 12:37 PM 11/20/2009

[alexf20c]

if this mods bypasses coolant to the intake manifold and throttle body, without interfering with normal coolant flow through the cylinder head, then it sounds much more useful than indexing spark plugs.

cooler intake air charge = freeing up lost horsepower. keep us updated if you give it a try.

[Pwnin O'Brien]

I'll give it a shot and take some pictures along the way and post em up here. I'll also post up the results, if any.

[Natedogg1701]

ya deff let us know if you get any benefits from it, a buddy of mine did something weird on his mustang but it works, real risky tho because the chemical is combustable. he has a procharger on his stang, and the he has a 2 foot section of black rubber hose that connects between the piping coming out of the intercooler and the throttle body. and inside the rubber he has little freon filled tubes, metal tubes encased in the rubber. obviously the idea is to cool the air going into the motor, and the intake hose is always cold to the touch, not to sure how effective it is, but i think its really risky because if one of those freon tubes leaks and gets into the motor hes fu!@&%.

[Pwnin O'Brien]

Finally got around to doing the throttle body bypass since it was nice outside. It totaled about $4.50 in parts (a hose barb connector and two hose bypass caps) and it took me about 30mins. to do (since I had to remove the intake and throttle body to get to the coolant lines). I'll let you guys know how it works after I give it a thorough test.

[01silvapathy]

Finally got around to doing the throttle body bypass since it was nice outside. It totaled about $4.50 in parts (a hose barb connector and two hose bypass caps) and it took me about 30mins. to do (since I had to remove the intake and throttle body to get to the coolant lines). I'll let you guys know how it works after I give it a thorough test.

Sweet man! And take some pics and let us know how she drives

[Buzzman]

Sweet man! And take some pics and let us know how she drives

Double that remark. Really curious to see how she goes.

[Pwnin O'Brien]

Here are a couple of pics of the finished product. Sorry for the crappy quality, I dropped my camera which broke it so I had to use my Blackberry to take these shots.

You can see in the following image that the upper intake manifold itself is being heated which will in turn heat the throttle body. I'm not sure of the upper intake manifold material, but if it is made of aluminum (which it seems it may be) then this mod should make a huge difference in the upper intake manifold temperature. You can see that I have capped off the inlets to prevent any debris from entering. They are 5/16" bypass caps.

In the next image you can see that I have used the 5/16" barb connector to connect the two lines which I have removed. This will not have any impact on the cooling system in any way, it merely provides another path for coolant to flow. I also zip-tied the coolant line up so it doesn't rest on the ignition coils.

[nbf6165]

So what's the verdict??

Worth doing?

[Pwnin O'Brien]

So what's the verdict??

Worth doing?

I haven't really gotten a chance to give it a good test. I should have a verdict sometime this weekend.

[Pwnin O'Brien]

Well, I've had some time to test the throttle body bypass and I have to say, this was by far the best mod I have done yet. I tested the mod on a 40 mile drive (20 miles each way). After each trip, I felt the throttle body and the upper intake manifold to check their temperatures. The throttle body remained cool to the touch the entire time. The upper intake manifold increased very slightly in temperature, going no higher than 85 degrees. The temperature difference is amazing, the throttle body and the upper intake manifold run MUCH cooler after the mod.

Now, the most important part, the increase in HP. Of all the engine/performance mods I have done to my Pathfinder, this was the only one where I could physically tell there was an increase in HP. Noticeably the most increase is in the lower RPM's (2,000-3,000) in higher-torque situations like going up an incline. I notice the car has much less trouble going up a hill and it stays in much lower RPM's during the ascent.

Now, this mod may not apply to all since my Pathfinder has the electric throttle body (versus the mechanical throttle body) and the coolant is routed through my upper intake manifold instead of the throttle body. However, I am sure that even if you have the mechanical throttle body you can complete this mod and see some improvement.

I cannot recommend that this mod be completed and I will not be writing up a HOW TO because I cannot vouch for all climates and elevations. This mod could potentially allow ice to build up on your throttle body thus allowing the engine to accelerate uncontrollably. If you complete this mod you must be aware of the possible consequences and complete the mod at your own risk.