dhirocz

iTrader: (2)

Just one less size and shape transition the waves have to endure traveling toward the valve. Ideally, the runner would be straight and not change shape until it dumped into the cylinder, but that won't happen. I have no doubt that it would help, but the real question is, would it be worth it? The answer to that question lies in uncharted territory so it's purely speculation, but from a theoretical standpoint it is a plus. How much we don't know, but I'm sure the factory didn't do it for the same reasons...cost wasn't worth it for the return and amount of changes it would require. They had enough of what they wanted.

I agree on the rectangular shape. If it were up to me the passages would be rectangular and the head wouldn't taper in toward the pushrod pinch. Would most likely make for a stronger runner as well.

Guest

I dont think there are any issues with the concept at all, it just needs to be executed properly. The base is a major problem. In its current form its useless, IMO. I would think concept aside, ASM needs to get with us on larger tubes to make production and availability feasible, and Edelcrock needs to ditch the current design for something that works. That is if people want to stick with the same appearance. It would make a lot more sense to ditch the appearance entirely though, for something that functions better.

dhirocz

iTrader: (2)

sheetmetal is the best way to go IMO. Sometime in 2011 I'm looking to put one on top of my 496... gen VI 454 stuffed with gen VII crap. Use some oval ports, maybe even ported peanut ports, and run it as a tuned port in a std wheelbase Silverado in front of a 4L80-E in place of the 4.3 V6. That should give a better indication of how well the theory works from the ground up.

1989GTATransAm

iTrader: (3)

I found this old thread by "oil pan 4". He did a very nice job of showing the harmonic ranges versus the length of the intake track in a chart. Like I have previously said I am shooting for 21 inches. I figure when my motor shifts say at 6800rpm it will drop right down into the 3rd harmonic range. Peak VE should occur at peak torque and that should be around 5000rpm on my motor. So hopefully everything will come out according to plan.


https://www.thirdgen.org/forums/atta...r-v.e-jpeg.jpg

IROC_Champion

very helpful

Nelz

Hey, can you post that .pdf from http://www.grapeaperacing.com/tech/inductionsystems.pdf as their website is no longer working?

Blackdog36

iTrader: (3)

Here is the induction pdf and also one about fuel systems from Grapeaperacing.

Nelz

Thanks, I noticed that the super ram intake dimensions are incorrect. When I measured the super ram intake runners measured 1.86" x 1.63." It's a "D" shape. The ones that are listed commonly are for the Accel long tube runners that look exactly like the stock or AS&M runners. I'm looking around the Internet to find the "equivalent" diameter but it's not a circle (duh) and some engineering forums list this funny equation

gbayfisher

This was a very interesting read! What ever happened to the project?

1989GTATransAm

iTrader: (3)

"When I measured the super ram intake runners measured 1.86" x 1.63." It's a "D" shape."

The problem with the Super Ram runner is the D part has the largest CSA. The narrowest spot/CSA is in the bend area. That is where the restriction is. Measuring either end does not tell the story.

dhirocz

iTrader: (2)

Too bad we can't run an LS style intake on the gen 1. If it were built right, it could potentially be a very nice (and expensive) piece. The port arrangement on the gen 1 doesn't make things easier though.

1989GTATransAm

iTrader: (3)

"Too bad we can't run an LS style intake on the gen 1"

The distributor would be the problem. It would play havoc on number 8 runner. Actually if you think about it what is the "basic" difference between an LS1 style intake and a Super Ram looking at the runner configuration. Draw each of them out on a piece of paper.

Nelz

This may be an old thread, but I found some more information regarding the Helmholtz effect as it relates to a motor (including the TPI) and also, this is probably the most technical thread with all the theory as it applies to a TPI motor. David Vizard wrote about it in his How to Build Horsepower book and was trying to understand it, you only have part of the answer.

The Intake Pipe (or Ram pipe) in the grapeaperacing article you posted alluded to this. And now, I sort of get the 3" MAF and why that was chosen.

Applying the formula SQRT(CID x VE x RPM) / (V x 1130)

So a 305 x .85VE x 6000 rpm / 180 x 1130 = 2.75" diameter inlet.

You can run the stock MAF and inlet track up to 7000 RPM on a 305 (or 302.) 6100 RPM on a 350 and 5600RPM on a 383.

The 3" inlet sizing, if you are counting on Helmholtz tuning will run up to 6000RPM.

The thing that trips me up is the throttle body.

The stock throttle body has two bores measuring about 1.89" each, multiplied by 2 = 3.78"
A 52mm has two bores measuring about 2.05" each x 2 = 4.1"
A 58 mm has two bores measuring about 2.25" each x 2 = 4.5"

Then comes the optimal length of the inlet tube.

For an engine turning 10,000 RPM, a plenum intake ram pipe length of 7-8 inches is required. For every 1000 RPM below that, add 1.75-2 inches.

Now, I'm not sure how to measure this, as from the filter to the back of the throttle body on my 88 IROC with a Superram, it measured 30.5" (measured from where the Plenum starts to where Y clamps down on the stock air filters. The Y from the filter to where the MAF connected was 20"!!!!!!!) This is too long according to that formula.

However, from the plenum to the front of the MAF including the round outlet of the Y is 12.5" (Assuming where the Y starts into a round circle and going to the back of the throttle body.)

A 12.5" length is for a motor with an operating range up to 7000 RPM

At 4000RPM, the intake tract to the plenum should be about 17.5" to 20."

A few things complicate this on a TPI motor (as compared to a Honda or LS motor with just one round throttle body blade)
-The throttle body is not one round circle, but two small circles. This makes the intake track require a circle to oval boot to connect the MAF to the throttle body and changes the way air is rammed into the plenum compared to a round pipe and a round throttle body.
-Of note "the intake tract should be sized to produce the most power before the Intake runners themselves kick in..."

And then there's a comment:

A V-8 with 2 induction pulses just 90 degrees apart looks (to the plenum) like a 3 cylinder engine with one of the cylinders bigger than the other two. So for this system to work on a V6 or a V-8, two plenums are needed. The intake runner must then be sized for half the engine's displacement. I think this is how Ferrari does it when you look at some of their motors, you see two plenums. For this to work (I think, but I could really be wrong her) with a superram or a TPI plenum, I would have to put a Plenum Divider in the middle. A dual plan apparently splits the injection pulses into 180 degrees. But I'm not sure how a TPI does this as every cylinder is separated in the base.


And then we get to plenum sizing.

A stock TPI plenum holds about 150 cu. inches which is about 50% of a 305 cu. inch motor or 40% of a cu. inch motor.

And then to the calculator that was sent out.

Although DV calculates an ECD value slightly differently.

Basically, after figuring out all that, you need to bend an intake pipe a certain length and then add a cone in front I suppose. (I didn't count the filter and I'm not sure if you do or not.)

But....when you start to run cfm numbers through all the diameters, it doesn't necessarily fit. So the idea of tuning for fast velocity through a small port for a certain RPM band vs. tuning for peak HP and TQ numbers using a carb and CFM numbers doesn't necessarily jive in my head yet.