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Posted by: bernbomb914 Aug 15 2006, 11:04 PM

I need to go to F/I and need to know about throttle bodies, what size? what make? etc.
has any one used TWM throttle bodies? I have a 2270 with split duration cam.
Bernie

Posted by: Randal Aug 15 2006, 11:57 PM

I'm using TWM TB on my Raby motor. Not running yet, but shortly.

Posted by: TimT Aug 16 2006, 02:55 AM

Ive used TWMs on a few engines. They are fine.

Posted by: crash914 Aug 16 2006, 05:25 AM

I have the redline weber...I would go TWM. They seem very nicely finished...

Posted by: Rotary'14 Aug 16 2006, 06:44 AM

I didn't like the way the TWM fuel rails looked. Too bulky in my opinion. I bought my throttle body from Australia (check the exchange rate!) I got mine cheaper than any TWM TBs I could get within the US including shipping. Nice air horns & linkage too.

http://www.efihardware.com/efi_throttle.html

like this one in the poor pic

-Rob


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Posted by: Jake Raby Aug 16 2006, 06:49 AM

I have continually made MORE power on a 2270 with 40mm T/B..

The best on the planet come from Jenvey- they are all i use now.

The TWMs got junky after the last batch of 2005.

Bigger isn't better.. I picked up 12HP by going from a 45mm T/B to a 40mm on my "2270 Type 4 Torquer" combo... The other 2270 combos have since followed suite.

Posted by: crash914 Aug 16 2006, 07:06 AM

Jake, how about a 2.7?

I think that I have 45's or 48's.

Posted by: DNHunt Aug 16 2006, 07:38 AM

Bernie

I'm using a pretty stock intake on my 2270. The throttle body is bored to 50 mm instead of the stock 45. It hasn't run out of air yet. I have graphs of the manifold pressure at WOT up to 6800 rpms and there is no decrease in pressure in the plenum. The big advantage is set up. Nothing to balance and manifold vacumm is easy to sample.

Jake ran an engine a while back with a smaller plenum and made more power so I may play with going smaller someday

The fuel rail is stock and the injectors are stock 2.0 L.

Posted by: Aaron Cox Aug 16 2006, 10:34 AM

TWM, Jenvey, and redline all make IDF and IDA flanged ITB's...

Jenvey is costly due to exchange rate

ITB's give you better throttle response over a single tb

Posted by: lapuwali Aug 16 2006, 11:08 AM

They're also very expensive, fussy to set up, it's difficult to run a cold start system with them, and it's hard to get a good MAP signal out of them. The throttle response advantage has to be weighed against other things. If you're running a stock flywheel, for example, you're not going to notice any advantages to throttle response over a *good* plenum setup.

IMHO, ITBs on anything less than a dedicated racing engine are bling.

Posted by: crash914 Aug 16 2006, 11:11 AM

BUT........bling is cool.....

Posted by: TimT Aug 16 2006, 11:24 AM

And now for someting completely different

Barrel valve ITBs. I wish they made these 3 Bbl. I would have bought a set for my 911. Notice you can also fire the injector directly down the barrel.

ITBS are no more difficult to set up thansay dualthroat, or triple throat carbs


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Posted by: Aaron Cox Aug 16 2006, 11:28 AM

injector up top like that is great....(formula 1 style... better atomization and high rpm performance right?)

but what happens if you get a backfire?

Posted by: TimT Aug 16 2006, 12:03 PM

Barrel valves with a carbon plenum on a 944T.

This car makes close to 800hp

sorry a wandering a bit off topic




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Posted by: bernbomb914 Aug 16 2006, 12:10 PM

I need to run the T/B because I am installing the DTM and it takes up the room over the engine. Jake thanks for the info about the size. I will chedk on the one in Austraila
Thanks fpr the input

Bernie

Posted by: Matt Romanowski Aug 16 2006, 12:17 PM

Barrel valves are cool until you need part throttle....Same thing with slide valves.

Ahhhh......Milledge Turbo parts.....

Matt

Posted by: Jake Raby Aug 16 2006, 12:51 PM

I prefer ITB over plenums.. Its not all bling- I see huge differences in all aspects of the engine and if I'm about anything its NOT BLING!!

They are NOT fussy and not hard to set up, they allow a much smoother idle and a much more radical camshaft to be ran- period.

Bern, I run a maximum of 45mm on an engine as large as a 2.8L, the only exception to that was the Mighty Spyder than used a 50mm on a 2.4 engine, but it was designed to run 9K RPM...

Posted by: Dave_Darling Aug 16 2006, 02:49 PM

And not really much (if any!) easier, either. Which is lapuwali's point. A common-plenum setup has none of those synch issues.




If you're motivated, you can fabricate extended intake runner pipes and just move the plenum up and aft... It's been done on at least one Bug conversion that I know of (I think Cali upright conversion not DTM though) and looked pretty decent.

--DD

Posted by: banksyinoz Aug 16 2006, 05:20 PM

I bought my throttle body from Australia (check the exchange rate!) I got mine cheaper than any TWM TBs I could get within the US including shipping. Nice air horns & linkage too.

http://www.efihardware.com/efi_throttle.html

i have seen these used here and they are good value for money here is a crappy pic of a set on a 20bpp, they are commonly used on turbo setups here also


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Posted by: Jake Raby Aug 16 2006, 05:59 PM

a common plenum is very touchy to camshaft and cylinder head designs. In some instances an engine with a plenum and a cam large enough to supply revs won't idle worth a hoot at less than 1400 RPM.

I/R is not that way. Both common plenums and I/R have their place in the world, a future 4th Dimension Radio episode will be entirely dedicated to my findings on each!

Posted by: DNHunt Aug 16 2006, 09:26 PM

I can attest to the idle situation. It prefers about 1400 rpms. If I go lower than that the vacuum starts to fall off. It will idle lower even down to 900 but, it lopes a bit and response off idle is a little dicey then. Kind of a compromise but who builds an engine to idle.

If I set it to 1300-1400 it's easy as can be to drive around town and vacuum is about .65 bar. At 1000 it's about .75 bar.

Dave

Posted by: Bleyseng Aug 17 2006, 08:41 AM

Even with the mild Raby 9550 the idle was a bitch to get setup at 950rpms. Tons of LM1 time to get the MPS A/F right. Ignition must be spot on! But it paid off as I have a rock solid idle (no hunting).

All combo's are going to need lots of tuning!

Posted by: ottox914 Aug 17 2006, 08:49 AM

I have twm's supplied by jake. you can share the adventure here:

http://www.914world.com/bbs2/index.php?showtopic=53733

I like the fuel rail set up- substantial.

Posted by: GTeener Aug 17 2006, 09:39 AM

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Posted by: crash914 Aug 17 2006, 09:54 AM

Wow, where do I get one of those kool Bling meters...

Lets take up a collection and send one to Jake....

Posted by: Jake Raby Aug 17 2006, 11:48 AM

It would end up under a 34" tall Super Swamper being crushed by the Pinzgauer!