Jump to content
SAU Community

Throttle Coolant Bypass. Rb25 - Rb20 - Rb30

psi

By psi,
in Tutorials / DIY / FAQ

 Share

Recommended Posts

psi Experienced

psi

Posted
Posted

This is a great little mod to lower the intake manifold air temp from around 77 degrees to somewhere near 45 degrees in summer, even colder in winter, great for making more throttle responce and horsepower! It bypasses the coolant in the throttle body.

You will need to find the throttle heater hose, which is mounted on the bottom of the throttle as part of the throttle. It is added by factory for 2 main reasons.

1: Because the throttle is heated to the same temp all the time, the air going through it is also raised which makes tuning the factory computer so much less complicated, the air is always about the same temp.

2: Due to the raised temp, the situation of thottle 'iceing' is removed. Throttle 'iceing' is where you drive though some moist cold air and the throttle actually gets little ice crystals on it and freezes it in place. When you go to lift off for a corner the throttle wont come back.. VERY SCARY! This sometimes happens in air temps below about 5deg. If this happens and the throttle wont come back, just push the throttle harder to brake the ice seal and then lift off, or turn the engine off..

The mod: built into the bottom of the throttle aspart of the casting is a little tube. you need to bypass this tube... simple! 2 easy ways to do this,

1: remove the 2 hoses from the bottom of the throttle, 1 from the 'do not open' bleed screw on the front of the intake manifold and then the other that goes back down the back of the engine to the firewall.. u will need to use 2 new hose clamps and about 45cm of hose. run the new hose from the bleed screw UNDER the throttle and onto the the back join on the fire wall.. or

2: just cut a peice of metal tube (copper, steel or alloy) a smidge longer than the throttle bodies hose barbs and use the standard hoses. just insert the new metal tube under the throttle and join it all up.

NOT FINISHED YET, now u have to get the air out of the system, that is what the 'do not open' screw is for. This screw is the highest point in the engine that the air will get to, so any time u disconnect ANY part of the cooling or heating system, you MUST bleed the air out. you will need a 10mm spanner. Start the cold engine and let it idle.

as it warms up, undo the 'do not open' screw a few turns(but not all the way out!). as the engine gets hotter u should see some bubbling come up though the thread, this is good.. u will loose a very small amout of coolant. when the bubbling has stopped, thighten the screw back up. Repeat these steps 2 or 3 more times when u start the cold engine(generally over a week of driving to work or whatever).

It is vital ALL the air is removed from the system!

This little mod is way less than 1 hour to do even if you take your time and tripple check everything!

The end result is an intake manifold that you can actually touch after a long cruise.. this means it goes harder. It looks totally factory, does a great job and gives more thottle feel.

Happy cruising!

  • 2 weeks later...
turbo_brian Community Regular

turbo_brian

Posted
Posted
has anyone tried this yet?

I have a Dyno day coming with another club, I am going to do before and after Dyno runs on the same car to see what sort of differences are made, I am also going to measure Throttle body temps for the duration of both runs as well.

B.

gl0ck. Explorer

gl0ck.

Posted
Posted
I have a Dyno day coming with another club, I am going to do before and after Dyno runs on the same car to see what sort of differences are made, I am also going to measure Throttle body temps for the duration of both runs as well.

B.

choice, any chance of loading pix after doing this little mod? also dyno pics?

turbo_brian Community Regular

turbo_brian

Posted
Posted
choice, any chance of loading pix after doing this little mod? also dyno pics?

I can load pics, but it will be of a non-Nissan, so not sure how helpful they will be...

Will definately get before and after dyno results.

B.

gl0ck. Explorer

gl0ck.

Posted
Posted
I can load pics, but it will be of a non-Nissan, so not sure how helpful they will be...

Will definately get before and after dyno results.

B.

yeah load it dude, shouldnt be any problem tryna figure it out.

- Mat

  • 3 weeks later...
psi Experienced

psi

Posted
  • Author
Posted

ok, sorry guys, I dont have pics cos i moved the throtle ages ago..

I will see if i can get to and mod one of the million skylines around and take foto's for you.

As for the AF ratio, I didn't notice stuff all change! The engine still consumes air in the same way, just that the intake temp is a bit lower, which in thery should have a more dense air charge.

If somebody has done a dyno run, that would be interesting.. I noticed that the throttle was more scrisp from cruise onto power.

This trick will work on any factory engine that uses coolant to 'warm' the throttle. In the old days of carby's, guys used to add a non-heat transferring device or spacer between the carby and the intake manifold to do the same trick. Yep, factories have been doing this to us for decades.

that help?

_x_FiReStOrM_x_ Community Regular

_x_FiReStOrM_x_

Posted
Posted

Good writeup!!... only downside i can see is the car will 'idle up' for longer as the coolant is no longer there to melt the waxpellet. It now has to rely on conduction of engine heat instead. But imo, its a worthwhile mod if you can put up with this.

  • 7 months later...
J3TR33 Community Regular

J3TR33

Posted
Posted

iv always wondered why my rb25 has those two nipples with nothing connected. But it seems like when they did the de+t conversion for my car, they got the water feed and return from these two hoses,

is this all good? is there enough water flow for the turbo?

thanks

gotRICE? Veteran

gotRICE?

Posted
Posted
in the 1st post it says, the coolant passing through the tb makes tuning the factory ecu alot easier, so is this mod stock ecu friendly?

Hasnt caused me any problems and its been done for months.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      gauge needle removal

      By GTSBoy · Posted

      Yeah, so widen your search to any Nissan speedo first, then go wider if needed. I will say though, that there is a better than even chance that what I said first will likely come into play. They quite possibly won't come apart without damage. I tried to disassemble a stepper gauge that I wanted to repair. There was no way that needle was coming off the spindle, and I could not see how the spindle would come out of the mechanism behind. Assembled once, never to be disassembled, was my conclusion. Could be the same on the R34 cluster. Failing that - take the cluster to a workshop that specialises in automotive instrument work. There's usually at least one in every Australian city. They'll either be able to do it for you for small cost, or tell you it can't be done. It might be that "it can't be done" unless you follow some arcane procedure, including trickiness to glue it back together or something, that only experienced techs know.
    • GTSBoy
      R-chassis INNER tie rod torque spec?

      By GTSBoy · Posted

      Well, given that I, an engineer, almost never bring out the torque wrench to tighten up chassis bolts, despite fully knowing the theory, and instead rely on feel, which I happen to know is exactly how the majority of mechanics do things, should tell you the level of actual peril that exists from not achieving exactly 88 Nm of torque. How about if I just say then that 88Nm is at the lower end of the correct wheel nut torque range? Everyone knows how to tighten a wheel nut, right? And almost no-one ever brings out the torque wrench for that task
    • hardsteppa
      R-chassis INNER tie rod torque spec?

      By hardsteppa · Posted

      Don't be ridiculous. "2-3 ugga duggas or one Oof. You have to use Oof on tie rods because you can't get an ugga dugga on there." Is not helping the guy at all.
    • JC71
      gauge needle removal

      By JC71 · Posted

      I have done a lot of research before posting here and on gtruk forum. couldn't find anything. I have my gauges all part except the needle itself. the needle has a extremely small hole in the center, but the shaft going to the needle is extremely small and appears to have nothing to index it either. doesn't seem strong enough to simple pry or pull without damaging something. Already tried the old spoon trick on a extra triple meter I have from a gtt, but no luck. the center cap comes off easily but the hole in the meter face plate aren't big enough to get over the needle itself. figured this would be my best place to find someone who might have actually removed theirs. wonder if there is some type of small pin press tool to push the pin in while pulling the needle base off.
    • Roy
      A Boy's Love For His Rb20

      By Roy · Posted

      Ok...its taking me long enough to finally do this.  Feck financial security...heart disease will get me soon enough anyway So welcome to the garage..."Clem" Belsil80 has been running a 370Z in Super TT series. So after entering with him in last years Winton 300 i figured I  need my own car. Seems SAU Vic race cars need to be yellow....{tick} Reckon with enough motor i will be able to make up for the lack of talent and stay ahead of the 370Z... but the LS powered S13 and E36s are a ways up the road Aim is to have a car that doesnt stop or turn but has a bit of shed built motor with jam...maybe some cream  First step is getting this ex drift car log booked I am keeping faithful silver car. As the road-club car gets upgrades the race car wil get the sloppy seconds
×
×
  • Create New...