Anyone using the Q45 throttle body?

[240240]

...just like the title asks? Also, what kind of modification needs to be done to use the throttle body?

Thanks

[Kansei240sx]

One of the guys here had a friend that used that throttle body on his RB25DET, with the greddy intake manifold and he says it doesnt run that well on the stock turbo that comes with the motor, if you're running close to the stock unit, i'd stay with the stock throttle body, and if your upgrading to a larger turbine then the Q45 tb wouldnt be a bad choice i guess.

As far as what you need im not entirely sure, i dont know if the TPS sensor is compatible with the RB wiring setup, and im not entirely sure how well if at all that it would bolt right on to the stock RB/20/25/26 intake manifold.

You could try asking Yellow4g63 he knows his stuff pretty well.

[300Plus]

I'm going with the 90mm Q45 on my RB25. I'm going with the stock turbo for the moment, with large FMIC and custom intake mani , so may hurt me with the stock turbo but that wont last too long. the TPS on the Q45 works and there is wiring info somewhere. From what I hear it will not bolt strait to the RB25 intake.

[integra7]

I have the Q45 throttle body.

You would only use if it you have a greddy intake manifold or a custom one. I am using it with the greddy intake manifold and it bolts right up. The only thing is that you flip it so its upside down (coolant lines on top). The throttle body also has a the fast idle system which is controlled by coolant temperature. Basically, when the engine is cold, the throttle body will open alittle bit to allow for higher idle, once the engine is at operating temperature, then the fast idle doesn't interfere anymore. If you don't hook up the coolant lines (most people don't hook it up) then you have to remove the spring and bracket from the fast idle system so it doesn't interfere with your idle.

Anyways, I'll try and post some pictures later today.

[eh?]

TPS on the Q45 will plug in if you have a SI rb25 motor/harness and other older R33 rb's. SII motor use a different tps type.Someone with a Q45tb/Greddy IM/PFC made 275 whp on 8psi stock turbo.

[integra7]

Yeah, forgot to mention that.....series 1 RB25 TPS and the Q45 TPS is the same. You will need to rewire if you have a series 2 RB25.

Anyways...here's a picture of the throttle body mounted on the greddy intake manifold. In the picture, the fast idle spring has been removed. And you can also see the the throttle body is upside down (coolant lines on top, throttle cable goes on the passenger side).

[integra7]

this is what it looks like with the spring still on...

[Wykid 240]

Why did you take it off?

-Jeramy

[300Plus]

Yeah I've got the Q45 TB about to go on and I can put it on either way. so please fill me in. Why take off, and would it be better flipped over the correct way (if the greddy allowed this i mean) thanks!

[integra7]

why did i take off the spring?

because i don't plan on running the coolant lines to the throttle body. therefore the fast idle mechanism on the throttle body will not operate as it should. this will cause your idle to fluctuate randomly.read through this post for more information:zerothread?id=135378

why did i flip over the throttle body?

the throttle body bolts on either way, but i flipped it over because when it is flipped over, it is aligned with the throttle cable bracket. its also in the installation instructions that came with the manifold.
Modified by integra7 at 8:37 PM 11/17/2005

[fly240]

if removing the spring, will this method works for the stock TPS...

[eh?]

The spring has nothing to do with the TPS. The spring disables the cold start acutator on the Q45 TB. The RB already has an electrical cold start valve. Leaving both on leads to a much higher cold idle.IF you have a SII rb25 your out of luck, the Drive mechanism on the TB does not fit the SII. Here is a pic to show the difference

[fly240]

my only have 1 plug which I think it's sI type rb.can I un-bolt the spring on the SI rb to lower the idle?....

[300Plus]

The spring has nothing to do with the TPS. The spring disables the cold start acutator on the Q45 TB. The RB already has an electrical cold start valve. Leaving both on leads to a much higher cold idle.IF you have a SII rb25 your out of luck, the Drive mechanism on the TB does not fit the SII. Here is a pic to show the difference

Yeah the RB series II doesn't fit but you can just use the Q45 TPS... Thats what I've always heard. that its just 3 wire that need to be rearranged.

Any specfics pic on what to remove and what not to?

[eh?]

Yes you'll be okay.

Yeah the RB series II doesn't fit but you can just use the Q45 TPS... Thats what I've always heard. that its just 3 wire that need to be rearranged.

Any specfics pic on what to remove and what not to?

Yes all you need to do is splice the TPS wires. Just make sure you get a TB with a tps, cause the tps is $$$...

[300Plus]

Luckily my came with one. I was going to ask when i got to that point but even tho its 3 wires which ones go where? is there already a post haven't searched.

[jdms13rhd]

Im running a NEO-6 RB25 and got the Greddy intake and Q45TB. I thaught the factory turbo would suck so I threw on a GT2535 that I had lien around and I also threw on a GTR intercooler and its not that impressive. I have factort RB25's that are faster and lightly modified SR's in Silvias that are faster also.

On the Q45 TB at first I didnt remove the spring and it was just pretty much a high Idle. It was at about 2300RPM with spring still in and once I removed the spring it was good once I adjusted the AAC Valve on the intake to a nice idle.

If anyone knows if I did anythign wrong with this set up to be so slow could they point me in the right direction?? Any tips can be very helpful. I was thinking of just trading a friend of mine and going back to the factory unit on the RB25.

Here is a picture of what Ive done. BTW I threw it in a S13 Silvia.

[eh?]

Check for codes? Your pretty much on your own with a neo rb25.

[Carl H]

is your nvcs working?if the constantly variable intake cam bit isnt working then its not gonna make power like it should, thats how the neo engines make so much more power.

[Yellow4g63]

this is what it looks like with the spring still on...

Holy crap didn't know about that. My friends idles funny on the cold start up and we couldn't figure out why.

[300Plus]

so anyone else have more details on wiring the q45 TPS to the RB25 series II ? the first time my motor cranks it'll have the q45 on it so I want to get it right so I don't have one more thing to trouble shoot. so any wiring help on that would be great !!

[zephyro90]

will this work on a stock s2 rb25? it has a 80mm opening

[300Plus]

I'm still looking for wiring info on wiring the Q45 TB to the series II rb25. I'm thinking of making a wiring guide if the info is not already available, plus i would like the help with the wiring, so please any help is great!

[300Plus]

I have the wiring schematic for the Q45 but I'm wondering if the wire schematic on rb25det.org is for the series I or II? I need it to be for the series II

Q45

RB

[sr240dett3]

I have a Q45 TB on a Greddy Intake manifold on a RB25

I have a S1, so i used the RB25 TPS

Click to Enlarge

Please dont mind the PVC, it was only to get the car started

[Swedish Mike]

Guys, what´s the stock TB diameter on RB25?

We run 450 whp here on 65 mm TB in Volvo and one 1000 hp V8 TT boat engine use 70 mm. Why 80 mm on a near stock engine?

/Mike

[eh?]

That RB tps pic you posted is a series I wire diagram . This is a SII schematichttp://www.rb25det.org/RB/skyline_r33_gts25t.gif

[300Plus]

awesome, I'll just look at the wire at the ecu and see their color and then ill know what is what. I'll post a guide for that as well

[dougal.fr]

Hi mate, just wondering if you succeeded in wiring the q45 tps to the series II rb25det??? I'm attempting to do the same now & would really appreciate ur know how on this matter...

[gtrperformance]

Anybody using the Q45 TB on a RB20DET? Does the intake manifold need to be modded?