Geoffrey

ITBs would be fit near the cylinder head with some type of common airbox for each side. I have done work with a variety of ITBs on turbocharged 911s. It takes a lot of time to properly tune and you need to have a system that has a secondary fuel table. The ITBs need to be mapped with TPS as the load and a second table for manifold pressure. Or you can use a MoTeC ECU which has 4 dimensional mapping. The 3006 ITBs from TWM induction have been a source of problems and they are high butterfly which I've found not to work well in a turbocharged environment. If you want to use ITBs there are other alternatives that are better. My opinion is that unless you are racing the car, your most easy solution is a 3.2 or 964 aluminum or plastic manifold.

Rob S

Mitch,

Come on down any time. I'm using a Carrera manifold and a 70 mm Edelbrock throttle body. Injectors are Siemens/Deka/Mototron high impedence 60 lb/hr (630 cc) injectors, running at about 3.2 bar. There's been lots of discussion on this board and others about ITBs on turbo engines; I would agree with Geoffrey that (from what I've heard) they're more trouble than they're worth for turbocharged applications.

Rob

A.Wayne

ITB"s on a turbo application for racing only , really not worth the effort for the street. you will not see any more power going from a single to ITB's but they will make for sure quicker lap times over the single butterfly TB.

Geoffrey

Rob, Please don't misuderstand my comments, I never said that they were more trouble than they are worth.

Contrary to what Wayne says, the ITBs to make more power than a single throttle body/common plenum setup with noticably better throttle response.

Rob S

Geoffrey,

I didn't mean to mischaracterize your opinion. What you said above is "If you want to use ITBs there are other alternatives that are better." Which I agree with. I'll go one step further to say, in *my* opinion, they're more trouble than they're worth...

Rob

fast951

I have used the DTA with great success. For my own 930 EFI conversion I'm still undecided on which system to use. The 3.2L Motronic (I reprogram it for semi-sequential, MAF & Wasted Spark) or the DTA system. I'm a Motronic guy (I convert it to work same as a stand alone), however I do like the DTA.

A.Wayne

Geoffrey,

I did say the ITB's have better throttle respone , but dis-agree that they make more power. you will see better torque curves with the ITB , but for all out power they are no match to a plenum type system with single or dual TB.

This i have seen to be consistent regardless of engine size or type. Now if a TB system flows better than a particlular single /plenum TB system , that might be so , but it is more a design problem or too small a TB than the topology..

Geoffrey

"Now if a TB system flows better than a particlular single /plenum TB system , that might be so , but it is more a design problem or too small a TB than the topology.."

Would you consider the 3.2 Carrera intake and throttle body to fit in that category?

A.Wayne

I would need more details , a 3.2 intake on what ? a stock engine ? a 9000 rpm screamer , a bored out 3.5 with big heads , A ITB system would flow better here over a stock 3.2 system for more Power/torque and throttle response. a stock 3.2 has a really small TB , restrictive for big turbo application .
Also ITB's are selected and sized for length /bore size etc based on what is needed /application , bore and stroke , peak rpm etc. as distance from the intake port will also be based on this ..

Geoffrey

I think that is the issue, I've never seen an ITB setup produce less HP or Torque than a 3.2 Carrera or 964 system, particularly at the lower RPMs as you mentioned, but also at the higher RPMs.

A.Wayne

I was commenting on the topology Geoffrey, not a specific a/b/ model.

an ITB system is a custom system , compare it to a custom plenum TB System and the differences will be pronounced..

A ITB system over a stock 3.2 is as you say there is no comparision.

911T

So, Who in the US Dealer for dta?

Geoffrey

A.Wayne

Rob S

There are other dealers too, including Dave Capurro, at C&C Automotive in Reno, who I bought mine from and who did my tuning. I suggest you buy from whoever you plan to have do the tuning.

A.Wayne

Huh, Not sure of your response geoffrey

Marco Manzie @ billett design.com is a dealer and i see that vitesse has also .
i have dealt with billet design in the past..