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Vehicles => Vehicle Tech => Topic started by: Terror_Flynn on June 14, 2023, 03:06:50 PM



Title: Larger DBW throttle body
Post by: Terror_Flynn on June 14, 2023, 03:06:50 PM
Interested in information about larger DBW throttle body for longitudinal 1.8t 20v engine that is maybe bolt-on or easy to modify to the intake/make an adapter plate, and works with me7.5

Size, maybe 65mm to 75mm?

Information about part numbers, engine code, maybe from completely different car brand?


Title: Re: Larger DBW throttle body
Post by: justinvw2646 on June 14, 2023, 05:01:18 PM
I have been running a throttle body off a CBUA/CBTA VW 2.5 for a couple years now. I did not make an adapter for it to the factory intake manifold. I drilled out all 4 bolt holes on the tbody and used washers with the bolts due to the enlarged holes. Gasket matched the inlet hole in the intake manifold. The only real trouble was finding a clamp that would apply enough pressure to keep the boost hose from popping off because the inlet for the throttle body is smooth. Hair spray and one of the nice bolt style boost hose clamps did the trick. Mine spikes 1.9 bar. This is installed on a 2002 GTi with an AWP. I did not have to repin the wiring connector.


Title: Re: Larger DBW throttle body
Post by: Blazius on June 15, 2023, 05:15:02 AM
Whatever TB you use(which you dont really need to change or get one from the same generation), you better have the flow maps and adjusted or have fun calibrating the modules.


Title: Re: Larger DBW throttle body
Post by: Terror_Flynn on June 16, 2023, 12:08:50 AM
What size is the vw 2.5 TB?

How do i know if an TB is from the same generation?

So tune and make an bigger TB to work correctly is not a easy and fun task.


Title: Re: Larger DBW throttle body
Post by: prj on June 16, 2023, 12:43:34 AM
You need the stock file from the car that you are going to take the TB from.
Then you need to copy over KFWDKMSN and KFMSNWDK to your software.

After that you need to do some pulls and adjust WDKUGDN until msdk_w and mshfm_w match.


Title: Re: Larger DBW throttle body
Post by: Terror_Flynn on June 16, 2023, 02:26:53 AM
Thank you PRJ, very good information about the tuning and run bigger TB.

Then in my mind it is easier if I use an VAG TB like vr6, 2.7t?
Because stock .bin files should I find here on nefmoto, so I can look up the TB maps.

Maybe some other newer VAG engine has a bit bigger TB?
Older engines and parts are getting more scarce on junkyards nowadays.


Title: Re: Larger DBW throttle body
Post by: prj on June 16, 2023, 03:23:21 AM
I don't know what you're doing with the engine, but 2.7T TB even standard one is easily enough for 600hp.
You can easily see from the flowmaps how much it flows.
The flowmaps are filled on a bench with values so that the pressure post tb is 0.528x the pressure pre-tb, at which any further flow is effectively stopped.

The RS4 throttle is not even linearized past 1700kg/h, which occurs already at 52%. It's basically so large that it can easily flow 1000hp, complete overkill.

The 2.7TT throttle at 70% flows roughly 1500 kg/hr.
The BAM throttle flows about 1000kg/hr at 70% (you can easily ignore the last 99% cells because they're just slapped in there and not real values).

So what are you trying to build?
Why do you think you need to change the throttle?

Before making such random changes it makes sense to fit a pressure sensor to the manifold. Then you can log the difference between the manifold pressure and the pre-throttle pressure.
If there is no significant difference, then changing the throttle is a waste of time. Which I think unless your 1.8T is making way over 500 hp it probably is.


Title: Re: Larger DBW throttle body
Post by: Terror_Flynn on June 16, 2023, 04:03:27 AM
Yes, bigger TB is probably really overkill as you say.
But I am also just curious.  

500-600hp from an 1.8t, it's not gonna happen for me. I'm shooting for about 400-450hp at the best, and on original displacement.
E85 fuel preferably.


Intake ports in the cylinderhead is larger, larger intake ports/runners, different cams.
Bigger turbocharger, like gtx2871r, g25-550, hx30.
I haven't decided on the turbo yet.