Throttle body size

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Haveacamper
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Throttle body size

Post by Haveacamper » Thu Jul 21, 2016 5:33 am

Hi guys,

I know this has been covered by almost every individual as my searches threw up many threads which i've read through. However, having asked the advice of a potential supplier of a throttle body I just to get other peoples views on what size throttle body I should be going for, based on the following spec:

Type 4 engine for superbeetle
2270cc (96x78)
5.328 rods
Web 86B camshaft
supervee type 1 lifters with bronze case inserts
44x38 heads with 8mm conversion on exhaust guide, 55-56cc chambers
exhaust is likely to be equal length headers with 150mm vintage speed superflow muffler

FI system will me megasquirt ms3x and hoping to go fully sequential with COPs

cooling system: i'm currently weighing up between DTM, porsche fan conversion kit, and making my own porsche fan conversion setup.

I'm aiming for a strong street engine for a superbeetle project - so something that is responsive off the line, but also through the range.

I will hold back the throttle body size that i have been recommended until i have others advice

i'd be looking at the IDF/IDA style bodies like the jenverys http://www.jenvey.co.uk/products2/twin- ... air-tfpxxi

Thanks, Haveacamper

66brm
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Re: Throttle body size

Post by 66brm » Thu Jul 21, 2016 5:50 am

From all the reading I've done I'm guessing between 40 and 44mm, being a T4 probably on the smaller end

Haveacamper
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Re: Throttle body size

Post by Haveacamper » Thu Jul 21, 2016 6:21 am

66brm wrote:From all the reading I've done I'm guessing between 40 and 44mm, being a T4 probably on the smaller end
The first bid is in :)

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Soul
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Re: Throttle body size

Post by Soul » Thu Jul 21, 2016 6:43 pm

42mm

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markvwguy
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Re: Throttle body size

Post by markvwguy » Thu Jul 21, 2016 7:08 pm

Vanagon 2.1l 50mm throttle body 82mm crank 94mm pistons.
Vanagon 1.9l 44mm

I use a vanagon 2.1 throttle body on a 1956cc TPS from a Volvo/KIA to the D shaft . The TPS D on these fit VW. I made the adapter plate from aluminum. Here are some pics from extra ones I fitted up; one 2.1l one 1.9l. I know people who use T body from 7 series Volvo. The VW throttle lever will line up with a factory T1 cooling dog house cable location. If fabricated in the same location as the German FI plenum.

Mark
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Dale M.
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Re: Throttle body size

Post by Dale M. » Sat Jul 23, 2016 9:14 am

JEEP has a nice single throat TB on their 2.5 liter four banger...Has TPS, air temp and idle air control on one single unit.... Nice for single TB on system...

This is pic of 6 cylinder model, but pretty much same as 4 cylinder model...

Image

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Soul
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Re: Throttle body size

Post by Soul » Sat Jul 23, 2016 10:19 am

If I had to do it all over again I'd opt to purchase a set of Chinese knock off Weber 40 IDF's from eBay strip them and use them as throttle bodies, then have injector bosses welded in the manifolds at the optimum angle. If it were a type 1 install I'd compromise and purchase the manifolds with the injector bosses.

The IDF clones are around $200.00 USD for the pair; you can get a TPS adapter from CB Performance and the 7056 fuel rail fits the injector spacing of the T-4 intakes. IMHO this would come out cheaper than anyone's throttle body solution or motorcycle ITB's and the PITA of coming up with spigot boots, adapters and such.

40 IDF's used as throttle bodies will flow enough for your requirements, if you feel that you need bigger purchase the 44 IDF clones they are around the same price on eBay if you shop around. If you feel you need even larger than that there's a pair of 48mm CB Performance throttle bodies for sale on the other site for $375.00. You can't beat that deal with a stick.

Haveacamper
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Re: Throttle body size

Post by Haveacamper » Sat Jul 23, 2016 10:26 pm

Thanks for the heads up guys. at the moment, i'm just trying to decipher what size throttle bodies i should be going for with my choice of engine spec.

anyone else have an opinion on suitable sizing?

Clonebug
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Re: Throttle body size

Post by Clonebug » Sat Jul 23, 2016 11:27 pm

38mm would be plenty.

Nate from Provolks is running them on his TIV and has nice throttle response with them.
Bigger is not always better.
You can always force more air into them with pressure..... :)
Stripped66 wrote:The point wasn't to argue air temps with the current world record holder, but to dispel the claim that the K03 is wrapped up at 150 HP. It's not.

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volksbugly
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Re: Throttle body size

Post by volksbugly » Mon Jul 25, 2016 11:37 pm

itb 30mm

single then do 55 mm

40mm throttle body flows aprox like 52mm carbs

The smaller itb will be better for street. It really depends on your target RPM

Haveacamper
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Re: Throttle body size

Post by Haveacamper » Mon Jul 25, 2016 11:47 pm

wow 30mm, that does sound small.

The typical size that I have found that people run ITB's on 1776 thru 2300+ is 38-44.

I was recommended 45mm which i thought would be a tad on the large side based on what i have read people suggesting on other threads as well as the importance of maintaining low end throttle response and high intake velocities

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Piledriver
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Re: Throttle body size

Post by Piledriver » Tue Jul 26, 2016 4:31 am

42-50mm for single, with ITBs you can get away with too big to some extent, but some folks actually like having an on/off switch for a throttle. Single is easy with stock cooling, and the factory T4 manifolds are excellent.
Upright converted, duals are really the only way to go, but a really good linkage is a requirement to preserve sanity.

I ran 44IDF/36s on an otherwise stock 914 1700 T4 (in a 914) and never managed to get quite the same gas mileage with FI. (Had CIS on that last time it rolled)

MS has been a huge win for lack of PITA and drive-ability, drives like a real car.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

Haveacamper
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Re: Throttle body size

Post by Haveacamper » Tue Jul 26, 2016 4:42 am

Piledriver wrote:42-50mm for single, with ITBs you can get away with too big to some extent, but some folks actually like having an on/off switch for a throttle. Single is easy with stock cooling, and the factory T4 manifolds are excellent.
Upright converted, duals are really the only way to go, but a really good linkage is a requirement to preserve sanity.

I ran 44IDF/36s on an otherwise stock 914 1700 T4 (in a 914) and never managed to get quite the same gas mileage with FI.

MS has been a huge win for lack of PITA and drive-ability, drives like a real car.
If I were to go for something like the vwspeedshop IDF style or Jenvey equivalent, then around the 42-44 mark would be suitable for my engine? This wouldnt restrict my airflow at the top end while maintaining good low end throttle response?

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Re: Throttle body size

Post by Piledriver » Tue Jul 26, 2016 6:28 am

44 IDFs with 36mm vents flow about like 36mm ITBs. Maybe.
38-42 max ITBs on a mild-medium rare engine up to `2270.

Huge or high RPM-only motors can go bigger, but I have 42s for my 2466.
I may try the 44 webers as ITBs, have a great Synclink linkage I want to use.
I, for one, regularly embrace our new robot overlords, as I am the guy fixing the robots...

Haveacamper
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Re: Throttle body size

Post by Haveacamper » Tue Jul 26, 2016 5:01 pm

Cheers for the clarification.

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