I ran the same numbers with the exception of the orifice. Since both blades open at the same time on the TB, I put in 10.4 cm for a 52mm TB and got this:

If I understand this correctly, there is no restriction here using this math?

I looked at the 52 vs 58 issue (after I had a 52mm that I bought before I decided to go SC) and decided it was not worth pulling the LT4 intake to port it to 58mm.

 

A single 10.4 cm orifice is WAAAY more flow area than two 5.2 cm orifices.

I halved it because only half the flow goes through each throttle bore.

Mike

 

Wouldn't you guys think at a certain point that the intake manifold will become a restriction. Has anyone ever flowed their intake manifold?

 

IDOXLR8, what part of the intake do you think is restrictive? The throttle bores need to be enlarged when using 58+ mm TB's. Next is the plenum, which is wide open. Then the ports, which can be easily enlarged.

Mike

 

I was referring to the ports. I have seen most people port out the throttle bores but leave the ports alone. Also I am assuming you plan on cutting out the divider from the manifold.

 

I tested pressure drop through my entire induction system when I had the single turbo.

From the outlet of the turbo, to the intake manifold, there was a .5 psi pressure drop. This is through the induction tubing/intercooler/58mm tb.

I was going to try a monoblade, but I've heard that the blades can bend when lifting off the throttle.

 

i have to agree with rich, i saw minimal gains from a stock tb to a monoblade both on the dyno and timeslips with a d-1 procharger. if you go to the monblade and start pushing big boost definitely get a big blowoff.

 

The gain is all theoretical but the flow differential as calculated is correct so therefore the gains could be correct. This is basic engineering for a given flow across a given orfice there will be a delta p across that orfice. Enlarge that orfice and the delta p drops. Theoretically more flow equals more power. However if there is just more flow across the TB it has to get into the engine and if there is another restriction before entering the engine ie; port size or valve size or exhaust (what goes in must go out) restrictions then the larger orfice at the entrance of the intake isn't going to make much difference.

 

Hey TJ head over to my forum.. made some changes

 

It has been questioned, as to the gain after removing restrictions in the intact tract. Why bother, when the boost can be cranked up a little. The gain is in lower temps of ingested air. When boost is increased, the additional compression increases the temp of the compressed volume. If the same amount of boost entering the cylinder can be achieved with lowered compressor boost, achieved thru less restrictions, this will translate into lowered intake temps entering cooling medium. This translates into even lower temps exiting cooling medium. We know that cooler air is more dense. As to how this (potential gain) may be reflected on a dyno, will depend on how efficient the after/intercooler(s) are allowed to be, compared to real world (on the road) outlet temps. With enuf heat soak, (EDIT: in intercooler) you could conceivably experience a LOSS of power/torque, when compared to real world operation.

Edit: Lower intake air temps are also less detonation prone.

 

So, arnie, what you're saying is that removing a restriction won't necessarily increase boost in the intake manifold, but it will reduce boost upstream of the restriction, the result being a supercharger that doesn't have to work as hard so the boost is cooler? And that this is better than spinning the blower faster (mine is already over maxed out anyway) since more boost means more heat?

Mike

 

That is exactly right. You may not move more boost, but even though the boost number is not higher, you will be moving air that has a greater density into the intake. As Arnie said, another great benefit is the reduced heat, and therefore less detonation. Removing intake/exhaust restrictions is always more effective than just cranking the boost another step up.

 

That is amazingly good! I assume this was measured at WOT. Was your intercooler air-to-air or air-to-water?

 

The statement "Why bother, when the boost can be cranked up a little", was supposed to be a question, with the following sentence the answer. Sorry for any confusion that caused.

Removing intake tract restrictions (especially) post compressor, WILL (at least potentially) increase the 'net' boost pressure in the manifold, from the same amount of compressor boost pressure applied. Will this reduce post compressor, but upstream of original restriction pressure? Answer: You could conceivably reduce compressor boost pressure (with hardware adjustment or whatever), yet achieve similar net manifold presssure, to what was achieved prior to the removal (or reduction) of the restriction. This reduced compressor boost pressure would result in lowered compressed air temps. Or, stated another way, you could retain the additional net boost that you gained, along with it's increased air temp.

Agreed! More effective because of the improved quality of the intake air, i.e. cooler and more dense.

 

Good discussion guys, I was wondering about going from a stock t/b to a monoblade. I think the answer is clear now, I shall be purchasing a monoblade now and plus its a very nice unite.