Throttle Body Bypass

[TiminTampa]

I'm not fimilar with this mod so what are the benefits of doing it and what would be the procedure?

[Towncivilian]

Your thoughts on throttle body bypassing...

I hadn't heard of it until you made this topic. Pwnin mentioned noticeable gains.

[TiminTampa]

I happen to run across this mod on the internet but I think I will be leaving this mod alone since I live in Florida and I don't know how this would affect my car in the hot temps but I appreciate the quick reply.

[Towncivilian]

I'm in Florida, too. Maybe I'll try it and see if I notice anything. The thread warns of potential ice build up in cold weather, but that's obviously not an issue for us. I'll post in this thread once I get around to doing the mod, but as Pwnin said a how-to is probably not a wise idea given the variation of climates and conditions where this mod may not be feasible.

[TiminTampa]

If you do this mod let me know how it works out if it works well for you then I will probably be the next to try it.

[Towncivilian]

I definitely will.

I just took a look, mechanical throttle bodies have the coolant lines and fittings exactly where Pwnin's 2003 electrical throttle body does, so this mod is certainly feasible for those of us with mechanical throttle bodies (2001-2002).

[TiminTampa]

I forgot his throttle body was electric mine is a 2002 so I'm sure it's mechanical as well but like you said I doubt it's an issue.

[TiminTampa]

So I was looking at my throttle body and I found the 2 coolant lines and it doesn't seem like you should have to take the throttle body apart to do this just remove the intake hose from the throttle body does this seem feasible?

[Towncivilian]

Yes, just remove the air intake tube to gain better access to the coolant lines and use a barb and hose clamps to secure them together as Pwnin did. I don't know what should be done with the coolant within the UIM/throttle body, perhaps one can blow compressed air through one end then the other to remove as much coolant as possible, or perhaps this is not necessary. Cap off the throttle body fittings and that should complete the modification. Check for leaks afterwards, of course.

[Ron Burgundy]

This is awesome!

Here's some really good information on it...

http://www.nicoclub.com/archives/thrott ... versa.html

I might even do this today (if its possible that is...haven't gone out and looked at my 99.5).

[Towncivilian]

This is awesome!

Here's some really good information on it...

http://www.nicoclub.com/archives/thrott ... versa.html

I might even do this today (if its possible that is...haven't gone out and looked at my 99.5).

VG33E equipped R50s also have coolant lines going through the throttle body/UIM.

Since I'm a little OCD about filtering, I might add a coolant filter using these coolant lines since they're the most easily accessed ones in the engine bay. See the later pages of this thread for cut opened coolant filters - seems that a lot of casting sand is present even with drains & fills / flushes. Of course, I'd go with a spin-on filter setup and not some dinky fuel filter as the poster in that thread used.

[TiminTampa]

Sweet I got the parts tonight doing it tomorrow. I'm going to use end caps and compression clamp them on the throttle body instead of cutting the ends off the lines on the throttle body. I think this will at least make a noticeable difference on the low RPM side. I've been looking for a throttle body spacer that would work on our R50's but still no luck.

[TiminTampa]

Where is the coolant filter located on the R50?

[Towncivilian]

Where is the coolant filter located on the R50?

There isn't one. I'm considering adding one using the throttle body coolant lines.

Also, what do you mean by cutting the ends of the throttle body lines? I don't think anybody ever suggested cutting anything - just capping off the fittings on the throttle body and joining the two hoses together with a fitting.

[TiminTampa]

It's what the guy did on the post that was on Ron Burgundy's post about the Versa Throttle Body Bypass and I was tinkering around with my friends engine in his 2002 Nissan Frontier and it looks like the same throttle body is ours and they offer throttle body spacers for that so might be a possibility.

[Towncivilian]

I don't see anything about cutting anything in that guide. The fittings are capped off and the lines are merged.

See this thread on NPORA about throttle body spacers. Looks like they're useless on any MPFI vehicle.

[TiminTampa]

Haha my bad he said cap off not cut off and I would think without clamping those end caps they would eventually fall off and did you use a 5/16" connector to connect the hoses?

[Towncivilian]

Yeah, definitely use clamps to hold the end caps on.

I don't know what the size of the connector is for sure - Pwnin said a 5/16" barb fitting worked for him, so I'd try that size first.

[Buzzman]

Just a thought for us cold weather guys (Canada):
How hard would it be to rig up a bypass valve for the coolant line?
In other words, put in the bypass hose as outlined in the modification, but have it hooked up to a Y connector at either end, along with a directional valve at the inlet side.
That way you can direct the coolant through the throttle body (in winter), and around the throttle body in the summer.
Shouldn't be too difficult I think.

[Towncivilian]

Buzzman, something like this?


(not sure whether inlet/outlets are correct orientation, the cooling circuit found in the LC section of the FSM is slightly confusing)

I hope I understood you correctly. Correct me if not!

Here's a simple diagram of a coolant filter set up using the TB lines:



Even if the filter clogs and flow is restricted, it's no big deal since the TB coolant lines branch off from the main cooling circuit - no critical flow goes through these lines and coolant will simply bypass the lines.

[Buzzman]

Town: Your first little graphic is exactly what I had in mind. Good one.
Later this spring I may just find a little spare time and see what I can come up with.
Right now I don't have any spare time to play with the Pathfinder.
FYI, I'm a sole proprietor business owner (home repair and small renovations), and this is my busy time of year.
(Also, my Pathy was at the dealership most of this week for the rust recall repair job.
Mine was still pretty solid, but I insisted on having the repair done anyway.)
Cheers.

[Ron Burgundy]

VG33E equipped R50s also have coolant lines going through the throttle body/UIM.

Care to point those out to me?

[Towncivilian]

I don't see them. Check this exploded parts view instead.

[ltsnotme]

VG33E's have a different cooling system:


Looks like coolant's going through the intake manifold itself first, then through the throttle body. Not as easy to bypass?

[Towncivilian]

Well, I'm not sure of the location of the hoses that lead from the intake manifold to the throttle body/UIM. Someone with a VG33E R50 will need to take a closer look for themselves. If the hoses are easily accessible, I don't see why one couldn't bypass the TB/UIM lines without a problem.

[ltsnotme]

Well, it looks like there's one line going from the intake manifold to the heater, and another line going through 'water outlet housing' to the radiator. Would you bypass the IM with a Y connector to make sure coolant gets to both the heater and the radiator? Not sure how much coolant is supposed to go to the heater and how much to the radiator...a Y connector would just split it roughly in half. Also not sure what the "intake manifold collector" is and whether it's ok to bypass it (probably).

[Towncivilian]

The intake manifold collector is the joined lower/upper halves of the intake manifold. Bypassing it will lower intake air temperature as well.

Without pictures it's a little difficult to envision the water piping setup, so I'd hesitate to say anything concrete at the moment. Try to get some pictures of the setup once you get a chance.

[Towncivilian]

Has anybody looked more into this yet? I've purchased a coolant filter base and a couple filters and am having difficulty finding 5/16" bypass caps and 5/16" to 1/4" NPT elbow fittings for the base. Not sure who sells 5/16" heater hose, either. I'm wondering whether the size of the hoses and TB fittings are actually 3/8" (which is 6/16").