Twins80s

iTrader: (3)

So I know some of you are just gona laugh at what is about to be said. Even I think it is kinda funny. So I am getting a TII sent to me today ( aluminum) so I was thinking would it be worth it trying to get an air filter by the scoop or.....(try not to laugh) swap to a turbo uim and put the intercooler on.

So what do you guys think? Is it worth the time or do I just enjoy the lower underhood temps?

RotaMan99

a ram air setup has been done before with a T2 hood. I forget who did it. Im sure someone will know. Ive heard it works well.

Tom93R1

iTrader: (2)

putting the intercooler on will just introduce a huge restriction. Anything would be better than doing that.

sc0rp7

iTrader: (3)

Putting the intercooler on will show no benefits... more along the lines of a restriction like was posted above...

One gentleman that did a "ram air" from the TII sccop did it on a PP engine that he had built... The main problem I foresee with this is that, while you are drawing in cold air... you are not inducing a ram air effect because of the location of the scoop. It simply is in a low pressure area, not a high pressure area.

As for the TII manifold... it may be better at higher rpms than a NA manifold... no conclusive research has been done to my knowledge... If it were me, I would try to mate a TII upper to a NA lower and drive it to see how the powerband is....

- Chris

NoDOHC

I have heard that same that sc0rp7 has, the turbo manifold is said to flow better.

It makes sense, as the runners are larger in the turbo manifold. However, losing the auxilliary ports will hurt the low end enough that the high end gains will not imporove your acceleration and will hurt your streetability.

Most ram air intakes actually pull air in from the high pressure region at the bottom of the windshield. I have seen ram air hoods for RX7s, but they looked home-made.

I like sc0rp7's idea of the NA LIM and the TII UIM (I tried this combo a while back, I can't remember what the problem was).

Maybe when I get home I can look again.

anewconvert

iTrader: (1)

bigger runners doesnt necessarily mean better. If the runners are too large then it will hurt runner/port velocity and actually reduce the amount of air that is ingested at high rpms.

On a stock or streetport the S5 NA manifold is better than either the S4 NA or TII upper. The VDI makes a rather large difference.


BC

rotarygod

iTrader: (1)

If you want to try to mate a TII upper to an n/a lower manifold, you need to fabricate an intermediate piece out of tubing to go between them. TII lower manifolds are much taller and they only have 2 piece manifolds. The n/a's have 3 piece manifolds and the lower manifold is much shorter. You can not just bolt an n/a lower to a TII upper.

sc0rp7

iTrader: (3)

I knew that they didnt just bolt together... I was merely suggesting trying to put them together (with an adapter if need be) to see what the results would be.

I agree that the larger runners may indeed lower velocity too much... I dont think that larger runners always equals better or more power, I understand the total concept. I was just stating that it may improve high end, while it may make it worse... not 100% sure what it does or does not till you try it.

As for S5 VDI, I know that it helps produce more top end power by reducing effective runner length (pressure wave tuning)... I was just curious as to if the TII intake would have comparable length before conversion of the waves, while still having greater flow, thereby giving slightly more top end power....

- Chris

RotaMan99

Im sure the "scoop" will stir up the fast moving airflow and cause a higher pressure at that point. If this scoop was so useless, why did mazda put it on? Why is this the place almost all turbo TMIC scoops are placed on all vehicals.

sc0rp7

iTrader: (3)

The scoop may stir up some air, but its not very effective... not to say it wouldnt work for this idea... (getting cold air, more "forced" in than if the filter was just say underhood)... The scoop would work great as a cold air setup... but it does not work well for "ram air"... look at Firebird's... there scoops are right behind the edge of the nose, that would work...

Look at the graphics of the high/low pressure areas on the 2nd generation rx-7... You will see exactly what im talking about. I am not sure why most manufacturers put them there, but the fact is that they dont flow alot of air through the scoop because it is not in a High pressure area as the high pressure areas are at the front of the vehicle (the nose) then the next high pressure point of air is at the base of the windshield or so when the air is again froced around another part of the vehicle... Ferrari and many other manufacturers have shown this... That is also why Subaru's scoops are farther back and higher, they're more effective at that position...

The TMIC idea is great for response but sucks for heat soak, thats why you see soo many aftermarket intercoolers that are front mount or v mount design rather than top mount, and im sure that was a big reason for mazda when they then went with a different intercooler position on the 3rd gen...

RotaMan99

I have seen the diagram for the rx7. I do not believe one bit that the scoop does not flow a good amount of air. That airflow in the diagram has no hood scoop there for you can not say its not a higher pressure zone. I do agree that its no where near as high as the nose of the vehical or possibly at the windshield but im sure its is forcing some air into the bay. Forcing air is categorized as "ram air". Im not talking about having 3-4 psi of air. Im only saying that air IS forced into the bay.

Now depending on how convoluded you make the intake to reach the scoop will decided how well it actually functions.

sc0rp7

iTrader: (3)

Ill concede to the point that the TII scoop is not in the diagram... I will also concede that any additional "forcing" of air is categorized as "ram air." I still do not believe it would be very effective at producing additional "pressure" in the airbox, but I also concede that I could be wrong. I have no proof that it would'nt and you have none to the contrary, that it in fact does.

That being said, if I were trying to do an all out NA I would definitely do some sort of shorter intake manifold and use an airbox directly under that scoop to get whatever benefits I could from having it (cold air and possibly some sort of "ram air" effect). I am not trying to kill an idea, I actually like the idea very much. I just was trying to be realistic about the benefits from it.

- Chris

rotarygod

iTrader: (1)

An intercooler doesn't function based on air pressure. It's based on flow. Yes this area has lower pressure than other locations but all that matters is airflow through the intercooler. Because of this it works fine. This isn't a good location for an air intake though. Take a look at the cars that do have intake scoops up here. They are very high off of the hood level away from the low pressure zone. Just because this isn't a good location for an intake doesn't mean that it's bad for an intercooler. Conversely just because it's a decent location for an intercooler does not mean it's good for an intake.

Even a properly designed ram air setup isn't starting to give any benefit until nearly 100 mph or so but it's benefit is greater with speeds increasing above this point. For a street car it's practically worthless. The only thing that really matters on a street car is "cold air".