You seem to be thinking that you'll be getting 4 throttle bodies on to your intake manifold--that's not how it works. If it did, your turbo would serve only to blow air into the plennum and out through your CAI. If this pic links in, take a look at an example of a quad manifold(RPW even):


Each cylinder will be getting its own throttle body, which will feed its own separate intake runner, each to its own cylinder. If you force air in to only one TB, that cylinder will get a lot more air than the other three, and you'll blow up your engine.

For a N/A setup, there are two ways to do this thing. For the more extreme path you go full-out drag style, poke the intake pipes through your hood, bend them forward and maybe put a screen over them. They usually don't worry about things like filters because the engine gets rebuilt every other race anyways.

To maintain any semblance of roadworthyness, the normal setup is to have the 4 TBs hooked up to an airbox, which acts similar to the plenum after the TB in the stock manifold. From there, you run a very large intake--CAI style or whatever. But only one pipe is really useful from there--two pipes can't do anything more than one big one.

Using a turbo with this setup is, IMO, utterly pointless. The point of the QTB is to get air into the cylinders with the least resistance possible. With a turbo, resistance between the compressor and intake port is almost irrelevant. Why? Well, flow resistance creates a pressure loss. You are controlling your pressure, however--if you want to overcome the resistance, just set your boost controller a bit higher. The amount of efficiency gained by a QTB wouldn't be any more helpful than tweaking the piping layout, until you get above the 600hp range or so. That is if it would help at all, i'm not convinced it will under positive pressure.

The drawbacks are huge, I did some searching and it seems that many people are running a haltech just to control N/A QTB setups. Controlling it under boost would be near impossible.

 

That's a downer, wish I had been in the whole modification business a long time ago so I could probably have more contacts with people who have actually done this sort of thing, basically I just talk to people on this board, which is a GREAT help by the way, because of people like you, who actually take the time and answer my questions, and the seller of the product whos main goal is to sell. As far as gains go...I guess that the best bet would be turbocharging then correct? (Gains seen by most QTBs that i've heard about are 50-70%) but theres no real way to continue increasing its hp output? Unlike turbochargers with the additions of BOVs, etc.

 

so then why not go quad turbo? eek! eek! eek! eek!

 

Can 4 Turbos bolt on? and is there a way to Intercool a Quad Turbo? LoL!

 

And where, praytell, are you going to mount four turbo manifolds? tongue.gif

Actually, the picture may not be quite as abysmal as I have painted it, but it still isn't very economical. I have learned that there are certain vehicles that come from the shop with quad TBs that have been fitted with turbos--the benefit being a very equal delivery of air to the cylinders. However, these are engines that are designed for the quad from the outset, our poor Betas are just not cut out for that type of service.

I found that RPW says that their quad units(I believe it was nissan units in particular) can be modified for forced induction, but refused to even estimate how much it would cost, saying only that extensive work would be required. Basically--with machining time and tuning--you're probably looking at tripling the 'normal' turbo cost, money better spent on the turbo alone wink