Thread: Interesting article - for all the itb haters...

Strange then that all the top BTCC and SATCAR Nissan Primeras and Sentras ran either ITB's or Slide intakes.

I think the point here is more for NA. So drop all the turbo intakes.

I am just bringing up what was in the article.

The clearly listed Skylines and GTIRs.

He actually addresses that very issue in the article.


I have problems with the article as well. He gives the Skyline, GTi-R, BMWs, etc. mentions for ITBs but then goes on and on about how great they are because they don't have a plenum and everything you can do when you don't have a plenum. Great, except all those factory cars have plenums as well.


ITBs are nothing special. They work in many N/A instances and some turbo instances very well. They are great at one thing which is throttle response. They have their place and other benefits, for sure.

But all that crap about equal flow and whatever is BS on factory cars because they still run plenums. Also, they try to relate equal flow with ITBs with equal length headers, which is complete madness. The reasons equal length headers work well are completely different from the reason ITBs work well.

The article goes off the deep end within the first or second paragraph. Many of the points are valid, but the reasoning is flawed.


Meh.

Ben, intake flow does have a direct affect on exhaust gas flow. As you have said, having ITB's on a turbine motor is just going to induce better response, it wont give any clear advantage in HP. When it come to n/a its a different story.

Equal length headers and intake runners are proobaly compared as they both have a peak resonance in which the air will flow at its best through them. Although trying to match a header for peak resonance is stupidly BS hard to make let alone calculate. The principal is the same, and the theory is the same - calculate your resonance and you will find your peak torque point, and also peak cylinder VE.


I honestly havnt bother to read through the article, it looked like a giant blob of word with no formatting - so i stayed away from it

By the sounds of the writer is trying to touch on a subject and relate two segments of ideas, which on different sides of the fence.

yeah in a drag car there is no real benefit to itb's. But how many gtr circuit cars switch to that same 100mm tb? The reason the drag guys do the switch is for ease of tuning at the track, but for a circuit car i would much prefer well tuned standard equipment.

there are many more benefits to going itb's than just power.

that's crap! itb's ban benefit most in boosted situations when tuned correctly.

When your force feeding the manifold with that much pressure of air, resonance theory and thrttole response is barely a problem. Infact when turbo charging you want more plenum volume and stored potential air then you do with n/a. ITB's unless being a slide throttle hamper airspeeds with turbos.

although i do agree with this, the benefit with itb's in boosted situation is when you have a set up that does require quite a large plenum set up which will end up creating stupid amounts of lag and really bad throttle response the itb's will be some of the best $$ you can spend on the car.

however yes depending on the set up eg; smallish plenum and smallish turbo (suited to each other obviously) yes itb's will make fudge all difference.

ITB's are the superior way when it comes to real racing, all the UK open wheel kit cars use ITB's on their engines....making 250-300 bhp on built 2.0L Ford and Vauxhall engines.

They will tick over at 800rpm and rev to 9000rpm.....On a B/K series or a VE you've got a recipy for win.

I have had a 4age 20v in my levin that came with a 16v 4age and ITBs are not that good, my car idled funny (high and low) and they were difficult to maintain (clean & adjust). The response was okay but not worth all the fuss. For force induction, I don't believe they should be used at all, that is why I would never buy a gtir engine. (No offense guys). Also I have only come across a few Gtir engines that idle evenly as well.