Throttle Coolant Bypass. Rb25 - Rb20 - Rb30

[W0rp3D]

Anyone tried removing the coolant supply the the manifold?

Anyone tried this yet?

I know this is an old thread but figured i would post here instead of making a new one.

[Dorifta]

its a bold move which i wont be doing, only reason i believe its there is to keep throttle warm to help air gain heat to aid in fuel atomisation

fine for a hot day, but prob not the best on a cold day, nissan put i there for a reason, if they didnt need it they wouldnt of wasted their money, its like canning the pcv valve and going for catch can, thats emission control

[psi]

Like I said, it is there for a reason..

..and, like I also said, IF you dont like it, change it back. No harm done. After all, your not welding anything in place!

You have to keep in mind that the engineer who did this, did this to cope with ALL kinds weather conditions in mind, for all kinds of drivers, at all sorts of altitudes.

Now, where I live, that doesn't bother me. I want the horsepower, with a smooth crisp responce.

That said, I did this as my very first engine mod, with stock ecu, fmic and cat back exhaust. couldn't feel a peak horsepower difference, but I DID feel a difference going from cruise onto boost (like I stated). I have owned my car for a bit over 7 years. No drama's, cold, hot, skid pan. makes no difference to anything else that I have noticed. Thats why I posted it up!

What is the point of running a front mount intercooler for reducing air temps, when you let the air temp jump back up to 77 odd degrees inside the intake manifold?? That is just silly! This is where this mod comes into its own.

It is not a big noticealbe difference like a lifting boost 3psi, but lots of tricky little things like this add up to a very nice package.

does that help you get your head around it??

[ascenion24]

Considering the velocity of the air traveling through the throttle body and the way the coolant is routed through it (and the amount that flows) I highly doubt it that there is enough heat transfer through the throttle body to raise the air temp any substantial amount. The whole system would of been designed to minimize this.

Unless there is dyno proof id say any noticeable gain is a placebo.

Edited November 19, 2009 by ascenion24

[08yannch]

i love these kind of mods. its like the stock boost controller mod (easy, cheap, small power gain)

there is no harm in doing this mod unless u live in a place that gets frost i dont so i will be doing this mod when i get the time.

[Kinks]

there is no harm in doing this mod unless u live in a place that gets frost i dont so i will be doing this mod when i get the time.

actually that's not quite right. you know how air heats up when you compress it? (like pumping up a bike tyre using a hand pump, or an air compressor). well the opposite happens when you let air expand. guess what happens with a closed throttle body eg at idle and light loads? it's expanding into the vacuum in your inlet manifold. the air temperature doesn't have to be freezing for that expansion to cause a problem, it will ice up your throttle and make it stick.

sure, not a problem on a 20C day when your underbonnet temps are 60C+, but it would make a minor difference at part throttle and no difference at WOT, the air is flowing through that area way too quickly to pick up any heat.

each to their own but I'd rather not risk the chance of a stuck throttle if I do venture into cooler areas.

[gotRICE?]

Deleted. Decided i cant be bothered.

Edited November 23, 2009 by gotRICE?

[West]

I used to own a 33gtst, i heat wrap the return cooler pipe and it works. How did i know it works? I had a lazer temp reading thing, i did a before and after test and the result was great.

This is a long time ago, 7-8 years or more so i can't remember exactly but it was on a hot summer day in Melb. Took the car for a spin, came back, pointed my lazer at the return pipe and it was reading around 70degree.

Wrap it up with heat wrap, went for a drive again, came back, did the same thing and it was only reading around 40degree.

What i'm trying to say is sometime these little mods help!

[WYTSKY]

Could you have been measuring the temperature of the heat wrap itself as oppose to the actual cooler pipe?

[West]

Could you have been measuring the temperature of the heat wrap itself as oppose to the actual cooler pipe?

Good question!

Though to think of it, if its the temperature of the heat wrap itself then the cooler piping must be a bit cooler than the heat wrap material since its wrapped in it?

[WYTSKY]

nah i would say the opposite... that the cooler pipe would be hotter... heat doesn't try to stay in tight... it wants to escape.... so those temperatures are probably just whats being emitted from the exterior of the pipe... i wouldn't imagine the pipe itself was much cooler.

[West]

nah i would say the opposite... that the cooler pipe would be hotter... heat doesn't try to stay in tight... it wants to escape.... so those temperatures are probably just whats being emitted from the exterior of the pipe... i wouldn't imagine the pipe itself was much cooler.

You could be right but the idea was to keep HEAT from the engine bay effect my return cooler pipe. This is the cooler pipe and not the exhaust dump pipe so i wouldn't think there will be much heat in it?

[BUKLUP]

hey guys i just pulled my manifold off and was shocked as to why the hell coolant was in the TB!

i want to get rid of them can i just put plugs in the hoses and leave it that way or do i have to connect them up in some sort of way? i couldnt understand the tut as i only just got the skyline and am mostly used to holdens lol

[TRB-001]

you have to take the hoses off and join them together with a joiner peice of pipe.

i would advise against this mod, as cooler air temps are good for air density, but its actually bad for fuel "atomisation" and unless u change your spark plug gaps it could cause missfires as cooler mixtures are harder to ignite.

thats even if it does make a difference.

[KrazyKong]

An interesting read for sure. Might look into this more thoroughly at some point in the future.

On a similar note, I've always wondered about the pipe going into the throttle body that comes from the intercooler. I may not be understanding things correctly, but shouldn't this pipe actually be as cool as possible? All the trouble with FMIC etc., then when the air reaches this pipe, the heat transfer from the top of the engine then makes the air hotter passing through this section. Then it gets heated again hitting the throttle body.

Has anyone wrapped this pipe at all to isolate it from the block heat transfer?

[PM-R33]

you have to take the hoses off and join them together with a joiner peice of pipe.

i would advise against this mod, as cooler air temps are good for air density, but its actually bad for fuel "atomisation" and unless u change your spark plug gaps it could cause missfires as cooler mixtures are harder to ignite.

thats even if it does make a difference.

There is coolant that goes through the runners next to the injectors which is there for fuel atomisation. The coolant in the throttle body has nothing to do with that. It is simply there to prevent the throttle body butterfly from freezing/sticking shut in cold climates.

You will find a hell of a lot of cars have this (including Commodores). If you know you won't be going into freezing temperatures bypass it. Simple.

Edited May 16, 2010 by PM-R33

[PM-R33]

On a similar note, I've always wondered about the pipe going into the throttle body that comes from the intercooler. I may not be understanding things correctly, but shouldn't this pipe actually be as cool as possible? All the trouble with FMIC etc., then when the air reaches this pipe, the heat transfer from the top of the engine then makes the air hotter passing through this section. Then it gets heated again hitting the throttle body.

Are you talking about the little vacuum line going into a small nipple on the throttle body? If so i'm pretty sure (going off memory here) that vaccum line goes into a hard line underneath the factory cross over pipe which then connets to the carbon canister. Since my setup is completely different from factory mine is just plugged up as it wasn't needed...

Edited May 16, 2010 by PM-R33

[Kinks]

An interesting read for sure. Might look into this more thoroughly at some point in the future.

On a similar note, I've always wondered about the pipe going into the throttle body that comes from the intercooler. I may not be understanding things correctly, but shouldn't this pipe actually be as cool as possible? All the trouble with FMIC etc., then when the air reaches this pipe, the heat transfer from the top of the engine then makes the air hotter passing through this section. Then it gets heated again hitting the throttle body.

Has anyone wrapped this pipe at all to isolate it from the block heat transfer?

Meh, the intake plenum is bolted to the side of the engine and it gets pretty hot too. It would be a minor difference, at WOT the air is not spending very long in the pipe at all and I doubt it would rise more than a couple of degrees in temperature.

[HtwCHACtkh]

actually that's not quite right. you know how air heats up when you compress it? (like pumping up a bike tyre using a hand pump, or an air compressor). well the opposite happens when you let air expand. guess what happens with a closed throttle body eg at idle and light loads? it's expanding into the vacuum in your inlet manifold. the air temperature doesn't have to be freezing for that expansion to cause a problem, it will ice up your throttle and make it stick.

sure, not a problem on a 20C day when your underbonnet temps are 60C+, but it would make a minor difference at part throttle and no difference at WOT, the air is flowing through that area way too quickly to pick up any heat.

each to their own but I'd rather not risk the chance of a stuck throttle if I do venture into cooler areas.

I wouldn't worry about that (though I think it is the only reason why that the coolant feed is there.

What you're saying is somewhat true, but you're forgetting that the volume of air increases as you let off the throttle and the bov opens allowing the volume to increase. So as long as you're not sucking in air at close to 0 degree's I wouldn't worry.

pV=nrT

T=pV/nr

n and r are constant in both situations.

So we're basically left with boyles law,

T=pV

On boost

T=2*1=2

Off boost

T=1*2=2

Pressure in atmospheres (so 1 bar on boost) and I used 1L for the volume for demonstration.

Boyles law from wiki:

Back on topic,

Doing this mod doesn't seem all that bad for conditions here in Australia. In Japan I'm sure it would get pretty nippy (I don't know for sure though!) but unless you live in Tassy or other places where the temperature drops down to less than 5 or 4C it should be okay.

Manufacturers make their cars to be as reliable as possible in all situations but here in Australia we are blessed pretty awesome (predictable) temperatures, I know when I was in the (ages ago) NT at Jabiru some cars came with a snorkel like thing to suck hot air from inside the engine bay to warm the engine up faster on freezing cold days.. The first thing you when you're up there is remove this!

How much it'll do, I don't know..

[r33cruiser]

How much it'll do, I don't know..

This. I did this 2yrs ago when i put on a front facing mani.

Didn't notice any difference at all.