I was looking around at coolant bypasses and started wondering who on here has one.

From what I understand, it's basically adding on small connection between the input and output for the coolant at the throttle body in an attempt to keep coolant away from the throttle body. This way, the TB will be cooler and we should expect slightly better throttle response and power.

Those of you have an NWP Spacer Kit have one that came with it.
Some others might have tried to make one themselves in hopes that this cheap mod (less than two bucks) could provide some gains in power.

The main concern for the mod is when it is extremely cold outside and without the coolant heating up the TB, it could potentially stick.

So my questions are:
Who here has a coolant bypass?
If you have one, do you live in an area where it gets pretty cold in the winters and where? (Something like the NE or Canada).
Does it make a difference in how the car drives, throttle response, fuel economy, or performance?
Have you had any issues with the TB sticking in the winter?
Has anyone avoided using one because of this potential sticking issue?

Any suggestions for someone living in the NE on doing this mod would be appreciated. It's not too difficult to take apart when it comes to winter time I suppose, but is it worth it to put it on?

 

My understanding of why coolant is cycled around the Throttle Body is to use the heated fluid to warm the TB in sub-zero temperatures so it doesn't stick. Right? Wrong? IDK for sure, really. There's some funny in the idea of using something called "coolant" in order to heat things up... but there it is.

NWP gives you this adapter so you can easily disconnect the inlet and outlet hoses that go to the TB, which is nice and all, but not required for phenolic spacer installation. It also leaves a lot of rubber hose lying around.

An alternative is to simply loop one of the hoses back around. Same net effect... less rubber. Here's a picture:



I live in Upstate NY, which only sees 1 or 2 sub-zero days a year, so I'm not really worried about that.

As to performance increases because of cooler air... who knows? I've got spacers, you see.

 

I have a bypass on my 00vi on my 95 and no bypass on my 2001 my 95 deff has better responce but is also more modded than my 01. I do get hard starts even during winter in florida though

 

My understanding is that the coolant keeps the TB warm in freezing temperature, thereby mitigating the buildup of water vapor (which could then freeze after turning the engine off). As I live in WI/Upper Midwest (when I am in the States), freezing temps are common. I currently use one of these:

 

Neither one of my Maxima's has this for a combined mileage of "a lot" and last winter was fairly cold, (-20ºF). No problems, not really anything noticed either.

 

^
I was hoping to see if people had problems or not if they DID have the coolant bypass meaning that they didn't have the coolant warming the TB during winters.

 

Ha ha! Manny needs to moderate himself.

I've not experienced any problems with my bypass (that I know of). However, my Throttle Body is brand new as of 5000 miles ago.

 

I guess I was unclear.

I meant both my Maximas have this done to them, (coolant by-pass, no warmth to said TB in stated conditions). I haven't noticed good or bad in eleventy billion years of owning both my Maximas and the mileage to show for it on both models (TBW & throttle cable).

 

ah I see, thanks for contributing nmexmax. So i guess it would be safe to have it even in the winter. Would you happen to know if it contributes at all to throttle response or performance or fuel economy? Im assuming that if it does help any of those, it won't be very noticeable

 

You know what? PM Aaron at NWP Engineering and ask him why he includes a bypass connector with his spacers. Better yet, forward this thread his way and get him to respond to the community directly. He's always helpful, and probably has the kind of authority you're looking for in your quest for bypass opinions.

 

I'm quite sure it's just an attempt to keep the intake air cooler. That is, during hot ambient conditions with an operating temperature engine.
Is there not also some concern to TB gasket leakage allowing coolant into TB mechanism and fouling it?

 

Where did you get that plate ?

 

Just did it recently haven't gone thru winter yet. But when I had my Spec V in 03 I did bypass and it worked just fine. You won't have any issues.
Anything to keep away the heat is a plus. Trust me your engine will generate enough heat for all other parts in the winter.

 

I don't think nissan understands physics. When it's cold there's hardly any moisture in the air. Why would there ever be ice?

 

I've had this mod for years and through NY winters I've never had problems.

 

Sooo without spacers there isnt a reason to do this? Maybe for the first few minutes after warming the coolant it would be "better" but the entire manifold is always evenly hot to the touch after driving.

Image you could hook up a seperate system that chills the intake manifold, but without spacers I only see it keep heating back up.

 

Just completed it today and I live in a fairly cold clime in N. IL and will report if any issues. But I view this as additional insurance against coolant contacting IACV. I have found corrosion at the pin base of at least 2 IACVs that have faulted and possibly a third to not closing TSP before starting.
Procedure: Purchased 5/16" brass split hose mender with the claw backs. Disconnected each hose from each side of the IACV/TB and joined each to the brass mender and clamped with existing. Capped each IACV port with 3/8" ID black chair tips and these aren't as snug as I would have liked but not certain I even need any but it looks more finished. Fired up with no issues. Maybe $3.00 with Cook County tax and might have saved me real money if done sooner. Ignorance isn't bliss! It's expensive!

 

live in cali, so for the most part don't need it.

 

I have a 2001 Nissan Maxima and I'm trying to do a coolant bypass. I was wondering If someone could explain or give me the steps on how to do it. Thanks

 

I have already posted the instructions here: https://maxima.org/forums/5th-genera...ml#post9010920

 

I did the bypass last week. I live in NJ, it doesn't get extremely cold here but cold enough. High temps in the teens last week during the day. I saw no real difference as far as performance but that's not the reason for doing the bypass. It's more for a peace of mind thing. Knowing I'm not going to fry my ecu is enough of reason to do it for me. Very simple and the cost was less than $2.00 so I'm happy.

 

ECU frying is only for 00-01. We don't have an IACV.

It can make a difference in the summer (helps reduce heat soak). With NWP spacers it's definitely noticeable.

 

You learn something new everyday then. Here I was worried over nothing. Thanks man.

 

But if you're auto, then you need to unplug the motor mounts or the ECU can still suffer the same fate.

 

Yea ok I got that right then

 

00 max here.... how the hell are you guys doing this without brass splits? there is no way either of these hoses are long enough to make this connection



am i supposed to bypass the egr valve too? even then i don't see how that hose is long enough...

 

Absolutely no need for any brass splits!
Read this doc: https://drive.google.com/file/d/0B6O...1fNlF5QjQ/view - there is a picture in it.

 

I did mine on a 5.5 gen with a brass piece in the middle. I just disconnected the two hoses of throttle body and inserted brass connector in between the two.

My question is. Is the coolant in have pressure or no?? If yes how much psi?? This is the line I'm taping for coolant for turbo.

 

the "picture" in your doc is a simple flowchart pic. the picture i posted above is the reality of what is in my engine bay.. there is no possible way to bypass with the existing hoses i have to work with

as a side (maybe related) note, my picture does not look like the one posted by rochester earlier in the thread. maybe there are subtle differences between early 00, late 00, and 01 models. i thought 02-03 has no iacv, but mattx's post above has me more confused

 

My car is an "early 2000" and the hoses are long enough (longer than 4") that I could just reshuffle the hoses. Perhaps Nissan shortened the hoses on later models, to save a bit of rubber. In either case, you don't need a brass splitter; all you need is a longer hose.

 

does your configuration look like mine? maybe my hoses are too stiff and it's not working but they don't want to stretch to work...

i do appreciate the input btw

 

You configuration indeed looks a bit different then on my car (my car was made in October 1999). My hoses are about 6-8" long, a lot longer than yours. Which year/month was your car made in?
However, the same "bypass principle" applies, as depicted in my note.

Note to Mattx: No point in doing coolant bypass on 2002-3 Maximas as these newer Maximas have no IACV.

 

i thought i was 6/00, but will have to check again tomorrow. i understand the theory of the bypass it just doesn't seem physically possible with my hoses.

 

I was asking if the coolant in line on throttle body is pressurized?? If so how much.

 

Identical to the rest of the cooling system (13 psi)? It's just a small loop off of the pipes.

 

Same pressure as the rest of your cooling system (this follows from Pascal's law .... ).

 

Excellent thank you both for the info. I want to tap into these lines for cooling my bb turbo. This will work out great.

 

[QUOTE=Rochester;8065906]My understanding of why coolant is cycled around the Throttle Body is to use the heated fluid to warm the TB in sub-zero temperatures so it doesn't stick. Right? Wrong? IDK for sure, really. There's some funny in the idea of using something called "coolant" in order to heat things up... but there it is.


It is funny until you turn the heater on.

 

Get the longer hoses and do it right or pay the price of coolant everywhere,\ and over heating too after air gets in the system. Been their done that. If you really need to use the old hoses just plug em, don't reroute....worked for me too that way.

 

http://www.foreignecurepair.com/Nissan.htm