So it was the exact same upper intake (not removed) and it was just a TB swap with a port match opening? I would enjoy reading this article.
Not sure why you quoted his question to me. The test he was asking about, and the one you appear to be asking about now, are of the same motor from bottom to top, with the exception of a swap from a 75mm TB to a 90mm TB on the same TFS Box-R upper manifold. The TB swap resulted in 14 extra hp below 6000 rpm.
It's also not going to want to rev out above 6k, which IMO doesn't take full advantage of the shorter runners in the Box-R. I think the Box-R would prefer to have an extended rev-range well into the mid 7k range, perhaps higher.
So it was the exact same upper intake (not removed) and it was just a TB swap with a port match opening? I would enjoy reading this article.
I dont really agree with this, mostly because of the fact that the person who spec'd out my camshaft stated that the intake and headers would be the two limiting factors concerning RPM and power. Until i see a test where a box R intake actually makes power past 7250rpm, i will take his word for it. I think the long runners are what hurt all of these EFI SBF intakes back. The runners on the Box-r are shorter than other intakes, but they are still much longer than a Victor Jr or a Super Victor.
I have a friend who was an engine builder. (Chevy Guy)
When i was building my 383 and was pondering these same questions he explained to me that the LS2 and LS7 had a 90mm Bore. my 383 is around that displacement and in intended for performance.
I too have a trickflow box r with accufab 90mm TB.
Chris
Nik, what took you so long? I knew you'd like the article.
I would've been one of those guys telling you that about a 75mm vs. a 90mm. In fact, I think I have said that to you in the past. I wouldn't have expected that result.
From that article, here's how I gather you could tell if it will make a difference in your motor. In the article, they recorded a vacuum of 1" at WOT. Switching to the 90mm TB resulted in a drop from 1" to .3" vacuum @ WOT. I'm assuming they were taking these measurements at high rpm. I would also assume that you'd need a combo where the heads and intake were not already the weak point in flow. Both of those assumptions should be evident if you measured your manifold vacuum, particularly if you can figure out how to datalog that info. Of course, keep in mind that a vacuum doesn't necessarily indicate that the TB is the cause - could be the MAF, filter, piping, etc...
On the dyno graph comparison, there was no hit to torque or power anywhere. The difference increased almost linearly as rpm increased. I would have expected the 75mm to start reaching its potential before the 90 mm actually made any difference. From this test, that does not seem to be the case.
I can't scan it for you, because I downloaded the digital book for $25. I think we can work out something better, though. Shoot me an email to Chris42Arnold@yahoo.com
I wouldn't expect drivability issues, but the tune would have to be more precise, since opening the TB blade by any given angle will result a greater difference in the amount of air that flows. To be more concise, you lose resolution regarding the TPS input at low throttle. Naturally, I'd expect a motor with a huge TB to be more sensitive to the throttle down low. So that means 1/3 throttle with the small TB might be more like 1/4 throttle with the larger one. At low RPM - cruising speeds, you might not feel a difference in acceleration between 1/3 throttle and WOT.
Until we see more testing, I'd hold on to it to verify that the Box actually does make more power on your combo.
Nik, if I head that way in the next year like we talked about (a big if) and you haven't swapped it, let's get together and do a little dyno testing, for the hell of it. I'm running a 75mm TB on my box upper, because the HP kit's piping is too small for a 90mm - that's what I was told. I have higher priorities to work through at the moment regarding both life and the car, but eventually, I'll fab up larger piping and switch over to the 90mm TB.
Chris
Interesting test, but I have to agree with Tom. The camshaft is the gatekeeper to all incoming and exiting air. The particular combination switch (intake) could be tailored towards one side or the other. Atleast that test is much better than many comparisons I have seen. A 75mm TB is plenty for that combination IMO.
The only difference between those two intakes tested is the TB opening diameter? The runner shape, length, taper, etc. is all the same?
[...] same motor from bottom to top, with the exception of a swap from a 75mm TB to a 90mm TB on the same TFS Box-R upper manifold. The TB swap resulted in 14 extra hp below 6000 rpm.
It feels like that's a bit of a hand-waved answer. Why wouldn't these supposed advantages of long-runners manifest themselves in that range with any cam?
How do you take advantage of a long runner intake? Cam it to make power in that powerband. Correct me if I'm wrong, but the XE274 is pretty well documented and should be a pretty tame cam on a 331 with plenty of vacuum and pretty streetable. It should produce plenty of low-mid range tq. It's also not going to want to rev out above 6k, which IMO doesn't take full advantage of the shorter runners in the Box-R. I think the Box-R would prefer to have an extended rev-range well into the mid 7k range, perhaps higher. So to me, it seems like this cam should be advantageous to the long-runner intake in this test, if anything.
Still, until I've seen otherwise, this article has shown me that the commonly held perception that boxes will trade low and mid-range power for high-end is a myth. Perhaps it applies to other designs, but it surely doesn't seem to apply in this test. Again, I welcome anyone to demonstrate their point with a different comparison between this box upper and a standard TFS upper.
The runners on the Box-r are shorter than other intakes, but they are still much longer than a Victor Jr or a Super Victor.
You could be right, but honestly how would this guy know? Has he done testing that indicated a loss up high in comparison to these intakes? Or, is it just an educated guess based on the runner length? What I do know is that the TFS-R intake can flow in excess of 300cfm with a port job. So, I'm thinking it should make plenty of power into high RPM.
Forgive me for my inquisitive nature, but I don't put a ton of faith in anything I haven't seen with my own eyes, unless it rationally follows from my own experiences...
Can you get the specifics on the combos he's run (cam, heads, intake, box or standard), dyno comparisons, or track comparisons, etc.? How does one determine that the lower intake is the restriction? Considering what they can flow, the volume is there to support some serious power. Have other boxes, like the Reichard upper, been tried with the TFS lower? That would reduce runner length, since even the box upper extends the length of the runners by about 3".
Nah, I'd be an ******* to call and start questioning a guy I don't know. Matter of fact, the only thing that comes to my mind for high revving intakes is the carbed stuff that has been modified for fuel injection. However, I'm I would like to check one place to see what he was running and how high he was spinning his motor, but alas I can't get there through this gov't computer - it's blocked for me. Do me a favor, if you don't mind, and google "marc arnold," which should show the first link about his EFI '93 cobra. He's running hydraulic roller cams on his combos, too. So, I don't think he'd be going much over 7500 RPM, but please take a look and let me know. I distinctly remember that he's running EFI and hydraulic roller with andersen high-rev cams and spinning the piss out of his motors to very impressive results. However, I don't recall the intake he used or exactly how high he spun his aftermarket blocked motors. Aside from that, I've never really delved into high RPM setups that go beyond 7k or so.
BTW, you were right to call me out about the box making power into the mid 7s as that was groundless speculation on my part. Point for you, sir!
Anyway, no worries bro. You're not calling anyone out. It's something I'd like to see too. If anything, I think Marc's car is evidence to support your point, though I'm not convinced yet. 7200 RPM peak ain't bad, though. That's a 7500-7700 shifted car, possibly higher.
Yea, but you're more open minded than some that I see on the internet, and (obviously, from this post) willing to learn and accept new ideas. There will be some that will see this test and only try to poke holes in the logic and ignore the results.
This is what I always try to tell people when the discussion turns to TB/MAF sizing. In a high performance motor, there is no "sizing" of these parts. There's no magic formula that helps you pick a TB size. You just select one that is big enough (within reason) to minimize manifold vacuum as much as possible at WOT. (...And this pretty much comes down to the size of the intake opening, or how much you can hog it out.) ANY vacuum at WOT is an indication of flow inefficiency upstream of the intake, and it is GIVING UP POWER.
The OEM has a pretty good handle on this thinking; the Coyote has an 80mm TB and the LS junk has had "huge" TBs for years. Why 5.0 guys are still limiting themselves to 75mm, I have no idea.
Mo air is mo powa.
Now, I have *heard* that the bigger TBs (like the Accufab 90) have different geometry on the butterfly valve lever that is supposed to modulate the blade slower at lower openings to help with this issue. I do not know if that is true or not, just what I've heard. Either way, I know of guys running 90s on STREET driven 302s with no problems.
Joking? Here we have a legitimate test where switching to the 90mm TB proved significant gains over the 75. It doesn't get any more clear cut than this: the 75mm WAS NOT "plenty" for that combination.
Not sure what you're asking...? See below.
Keep in mind, Chris, that the cam does not dictate the rpm band of the engine alone. It is the combo of parts that does, and I think that is part of what Tom was getting at above.
It would be my guess that a more aggressive cam might help the long runner intake shine a bit more, but maybe at the cost of some drivability. Of course, put that more aggressive cam in the box intake engine, and it will likely rev even higher and make even more power, so I'm not sure that camming the long runner intake engine would necessarily help it outperform the box intake engine, but maybe just help it do better than it did in that test.
Of course I'm generalizing here a little bit. I know cam guys will do different things with valve events given the style of intake used. That said, if a GOOD cam guy were given the opportunity to create a cam tailored to each intake, my hunch is that the Box might still have the edge. Who knows.
It's all about the combo, hell, I've seen guys with iron GT40 junk make 350 to the tire and run 11s. There are just obviously better parts to help you make more power when put together right, and I think this article is good argument that the Box R is a serious piece.
Yea, I've thought about this before. The runners in the lower intake alone are longer than those in a single plane intake. Runners in a single plane intake are shooooort.
I believe that questioning and testing ideas (and parts) is a way to learn and accept or no longer accept ideas. You say, poking holes in logic, but I see trying to understand why "it is, what it is." In fact, this open mindedness led me to go a bit crazy with my 306 with the "bigger is better theory". I have an AFR 185 comp with a custom camshaft that mirrors and exceeds many 347^3+ camshaft specs, with a heavily ported SMII that dwarfs the Performer that was on it, to the tune of 30-40% larger runner area dimensions (measured myself), but guess what, the runner length is near identical. Ed must have got this one wrong
I agree with this completely, but it seems to be out of context of this test. I did not see anyone stating a magic formula to pick a TB size. In fact, this should show that it entirely depends on the engine combination, otherwise we would be guilty of the very thing we preach against (i.e. We see dyno results on ONE engine combination and believe it is the answer. In other words, we see a TFS-R vs. TFS-R Box comparison and assume that a shorter runner with a large box style plenum is the answer for all 331's.) This is a post hoc fallacy.
Assuming you are speaking of pressure drops behind the TB (or whatever intake piece you want), there is diminishing returns with this method of vaccum. Say you have a 331 @ 6,000 RPM sitting at 100% VE, this equals 575 cubic feet a minute. Place a TB that can flow 1000 CFM and then add 200 more potential cfm and you just get a .209 value drop in vacuum, but if you move from a 800 cfm TB and move up 200 more potential CFM, you get a .384 value drop in vacuum. So I am with you here.
When building a motor, the question is more along the lines of "why not?" rather than saying "I think this will be enough." I basically pick the throttle body first that works, and 2nd try to match it to the inlet on the upper. I would have gone with the 90mm on my own combo, but it won't work with my HP turbo kit. I'll probably modify the induction at some point to take advantage of the benefit. I might find that it reduces my exhaust pressure ratio problem a little as an added benefit.
Isn't that always the case? So the question really becomes, are you better off, worse off, or indifferent in using either intake when building the combo from scratch?This is true, IF the other induction parameters (valve events + intake system + exhaust system) is matched.
We know this stuff. Those of us actively participating in this thread are beyond this level of knowledge.Slapping on a large intake on an already good performing engine could hurt as well as help it. The volume of a larger intake (or smaller intake) may be productive (or counterproductive) to the efficiency of the engine.
No need to hear any longer, this is true for many aftermarket TB's. Refer back to the nautilus cam talk (which is like MOST OEM's now) + many are going to drive by wire set-ups, so touchiness or sensitive pedals are no longer an issue. The computer controls tip-in; no longer the other way around. I do not see any problems with a 90 mm TB on a 302, in fact, if we looked at just driveability (for the sake of healthy debate), I would prefer a larger style TB on a lower powered engine actually (302 vs. 427).
Cool. This makes sense. As I typed up my last response, I thought it would be cool to design a throttle body to do this. Probably should have realized it was already standard in design. Clarify the reasoning on your last point. I can't imagine you'd want to put a 90mm on a 302, and a 60mm on a 427. What are you trying to say there?
Serious - do you not believe that the pressure drop from the 3"^2 area from the 75mm TB to 90mm opening could cause an issue? Bernoulli principle at work. Do you think the box style could attribute more to a larger TB? I do. After all, when does the "plenum" begin, when the throttle is WOT?
The only issue I believe it caused was a gain of some pretty decent HP. So I don't see how you can defend the statement, "A 75mm TB is plenty for that combination," which is what he's asking if you're serious about. I don't see how you can say that after seeing the results, either. 75mm was clearly not enough for that combination.
I'm not sure what that last question is getting at. The plenum begins at the inlet. Naturally everything in the intake tract is an extention of the component before it, though. What's the point there?
Yes, you are correct, which is why your comments seem to contradict themselves. You are speaking about the TFS-R Box as how "bigger is better" prevails, but it is the combination of engine parts/tune that make this happen.
Bigger appears to be better. If I were a bettin' man, I'd put my money on the fact that this box intake will come out on top (power, ETs, etc...) if the only part you restricted in the build was the intake manifold to compare TFS Box-R, and TFS-R.
Great point.Your comments about adding a more aggressive camshaft to the TFS-R (non-box) seems to imply the "big head/small camshaft" theory. Well, Ed decided to go bigger on all parts of my new combo, but it works because it is matched - so I take it there are more ways to skin a cat.
A large cylinder head + intake system may like a delayed intake opening (or at least slow beginning ramp rate) so when the piston speed increases on the intake stroke towards its peak speed, the draw on the intake runner (head + intake) is greater. This is when the curtain area should be maximized in a timely manner. The change in air pressure will increase the air speed (some call it velocity) and will bring inertia with it. You need less duration. Matched parts become crucial when you go with various parts, like small or larger intakes.
Ok... now we're getting into a tech discussion that I've always wanted to understand, but have never devoted the time to, or had someone I felt confident in explaining it to me. So, I'm going to take this and your remaining tech comments regarding cams and open a new thread in 5.0 tech, I believe that subject diverges from the TFS-R vs. Box-R discussion. Please join.
Yes, you are generalizing, but it makes discussion better. I am not sure I agree with your assessment by looking at the "all else equal" situation you are creating for the cam pro. It depends on the combination entirely. Of course, one could have the exact same heads, cam, and intake, but yet run entirely different times or drive completely different. I would estimate there are 100 different reasons for this that are obvious, so I believe it is incorrect to look at this dyno run that FastDriver showed us from back in late '05 (put in MM&FF in March '06, then published in the book in '08) and assume that a TFS-R Box is better for all engines "all else being equal."
In fact, here is the results of a 30 second google fest showing how a TFS-R Box did not work for some. I hope this reaffirms that the combination and goals are what matter, not just the intake:
C'mon... you know me, David. We've spent plenty of time jousting here back in the day. I'm offended (not really) that you didn't think I've already done a google search or two... The problem is that those are not well documented, and certainly not as clean as a scientific test on the dyno. The first example has, at least, a little merit where it sounds like the guy legitimately put time and effort into getting the tune right and trying to make the combination work. The problem is it's anecdotal. We can't see the details, like cam specs, testing methods, resulting tunes, etc... We don't get to see what happened to the powerband. He talks about changing his shift point, which adds a variable that may not have been the right way to go, and doesn't talk about whether or not he tried shifting lower with the Box-R. If you know the guy - on Hardcore from earlier this year, right? - ask for the dynos and the tunes. I would love to see how the car combination reacted when it was changed. We don't race dynos, but in a situation where we're comparing components and finding optimum shift points, they can be extremely effective, and they produce consistent repeatable results. However, I suspect that the guy didn't dyno it based on his comment that he believes he lost some low end - probably would be something he knew and could attest to if he had a dyno in front of him.
The second example is laughably stereotypical of internet generalizations: "My buddies *insert engine, or vehicle information here* lost *insert rounded number here* with that *insert engine component here*.
In short, one dyno or a couple test can not conclude that a 90 mm TB is needed or that a box intake is best for all engine combinations. Those famous words we hate to hear so much:
Hopefully, one dyno is just the start. Show us another where the 90mm TB was no advantage or where the box intake was bested, and lets really begin the discussion.
I just wasted 30+ minutes and just scratched the surface.
It was no waste. Come dig a little deeper in the cam thread and teach me some ****.
I believe that questioning and testing ideas (and parts) is a way to learn and accept or no longer accept ideas. You say, poking holes in logic, but I see trying to understand why "it is, what it is." In fact, this open mindedness led me to go a bit crazy with my 306 with the "bigger is better theory". I have an AFR 185 comp with a custom camshaft that mirrors and exceeds many 347^3+ camshaft specs, with a heavily ported SMII that dwarfs the Performer that was on it, to the tune of 30-40% larger runner area dimensions (measured myself), but guess what, the runner length is near identical. Ed must have got this one wrong
Assuming you are speaking of pressure drops behind the TB (or whatever intake piece you want), there is diminishing returns with this method of vaccum. Say you have a 331 @ 6,000 RPM sitting at 100% VE, this equals 575 cubic feet a minute. Place a TB that can flow 1000 CFM and then add 200 more potential cfm and you just get a .209 value drop in vacuum, but if you move from a 800 cfm TB and move up 200 more potential CFM, you get a .384 value drop in vacuum. So I am with you here.
...
I am not sure who you are referring to on limiting their engines to 75 mm TB's. Most engines out there do not need the extra 3^inches from a 75 mm TB to a 90 mm TB.
Serious - do you not believe that the pressure drop from the 3"^2 area from the 75mm TB to 90mm opening could cause an issue? Bernoulli principle at work. Do you think the box style could attribute more to a larger TB? I do. After all, when does the "plenum" begin, when the throttle is WOT?
The problem is that we all contradict ourselves on a regular basis. We preach, "it is the combination", but then pick out the POSITIVES when we see fit, but neglect to mention that the combination probably played a large part in the results that you believe we ignore. Luckily Tom Moss reminded us of this.
Yes, you are correct, which is why your comments seem to contradict themselves. You are speaking about the TFS-R Box as how "bigger is better" prevails, but it is the combination of engine parts/tune that make this happen.
Go read some Gordon Blair stuff, in particular Design and Simulation of Four Stroke Engines. He literally has a couple hundred pages of research in intake designs. I own it and have read through it a couple years ago and the more I read it, the more questions I had.
Anyways, back on topic. For sake of argument - let's take the aforementioned XE274HR on this 331. Given the specs of that camshaft, the TFS 185 heads, I get a optimized 3rd tuned harmonic of ~12.9". Well, low and behold, the TFS-R BOX (9.0") + TFS 185 (4.75") length equals 13.75". This is less than an inch from ideal. However, add the extra 2.00" on to create the TFS-R runner length + same cylinder head, you get 15.75" - even further from ideal. The TFS-R BOX fits much closer, compared to the previous dyno run using a tuned length an entire two inches off near optimal. I wonder why the power went up?Factor in the assumed increase in taper from the BOX upper to lower, and you get even closer to the needed harmonic for a 12.9" length runner.
It was not a coincidence that at those funny RPM's (3700 and 3200) that we saw variations in HP/FT LB numbers at the wheels - tuned length and other intake parameters played a big part in this.
Yup, rising from the ashes here, great thread btw. So i was thinking of this entire longer runner v.s. shorter one results with a smaller cam with larger heads idea, ...which is kinda where i am because my P heads have been super ported, hence my 320rwtq with an Ecam and 1.6 rollers with a ported Cobra intake. If i went to an TFS R intake how much more pop I'd really get. I mean it's way more air but do you think my 220/220 duration would like it in N/A form?? I could even add 1.7 rollers if i wanted more lift, maybe be at a .536 then, thoughts anyone??
Like @5spd GT said above, "it depends". Switching up to better flowing parts and a more optimized cam is only ever going to help your situation, though.
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?
We use cookies and similar technologies for the following purposes:
Do you accept cookies and these technologies?