EFI Intake/Throttle body info

[1987cp]

Assuming there are no fitment issues with the style of box upper intake you want to use, it will be fine.

This is interesting ... I guess I'm left to assume that in stories of Mustangers complaining about poor performance with a box intake, they are either suffering from issues with installation, tuning, or overall combo, or else are comparing it to something better like a Performer EFI, etc.?

[Outlaw440]

Compared to a 140hp/280 lb-ft 351W ... yup!



It hasn't helped that everyone has jumped in with the "stock stuff is always better" routine. Lots of GMNers like factory-based upgrades a) because secondhand factory stuff is cheap, and b) because it's adequate for what most people are doing, especially those who will never upgrade their 4000rpm shift governor. Truth is, even the fabled 5.0 HO stuff was only really impressive compared to the 110hp "performance" cars from 1980-81, which is why folks are able to make big improvements without spending a huge amount of money (like Scott's and Thain's cars that both use OE Ford cams and intakes).
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I am not disrespecting anyones car by any means, the common goal is to build something your happy with after all, but i would like the info to be out there as far as how to make more power.

What you mentioned about the stock stuff is always better routine that always is being mentioned on not only this forum, but lots of others, is what really cripples the majority of people seeking info on SBF performance. The small heads, little cam, and stock intakes (while great improvements for these cars) is not necessarily the best performance wise. Modern vehicles like listed are miles ahead in technology and power/efficiency per engine size, the most common engine i bring up is the modern LSX motors, which compared to SBF's are using monstrous heads, intakes and cams, all in factory vehicles (trucks, suvs, you know, where torque is at a premium) and they are also used in lighter cars like corvettes, F bodies etc. because they are such a versatile engine that makes power all across the powerband. I am not praising GM by any means, chrysler does the same thing with the modern HEMI engines. I use the HEMI and LSX motors for discussion because they are the best OEM example of what modern technology has done with pushrod motors.

[Outlaw440]

Its looking more and more like i am going to also have to bring some Cylinder head writeups of mine here as well, but that will be another thread.

This is interesting ... I guess I'm left to assume that in stories of Mustangers complaining about poor performance with a box intake, they are either suffering from issues with installation, tuning, or overall combo, or else are comparing it to something better like a Performer EFI, etc.?

Without actually seeing the combo and what the particular issues were its hard to say, but it sounds like more than likely the issue is one of the things you stated.

-The next issue i wanted to touch upon is the famous tip-on-off throttle BS, where people will claim that a 90mm TB will be WOT at half pedal.

-I was able to compile the following data (as in facts) regarding the difference in length from the accelerator cable stud to the center of the blade shaft. This dimension will be refered to as "Throttle Radius", and you'll see why.

TB Size (mm) Throttle Radius

60 (Stock) 0.95"

65 0.994"

70 1.01"

75 1.05"

90 1.10"

You would ask.... what is so important of such a "radius"?...... simple. Archimedes law of the lever. The longer the radius from the fulcrum, the more movement will be required at the end, to cause the lever to raise a smaller distance. Or as shown below.....



The arc of AH needs to be bigger in order to create a smaller arc at KB. This goes along with the famous "tip in", on-off descriptions you see when bigger ID TB's are mentioned. .... the Archimedes law of the lever is exactly the same principle used between 1.6 and 1.7 rocker ratios. So yes, the analogy is NOT an "apples to oranges" comparison ... as some people fail to grasp the concept and the principle used.



.......... using that data, I made a quick comparison chart for the different Throttle Radius per TB ID size and look at the results.



The first row of numbers is the actual linear travel of the accelerator cable. The max is 1.35". Now... attach an actuator from 0" to 1.35" and change the Throttle Radius of the accelerator linkage plate. A 1" linear travel of the cable = 60.31° for the stock TB, 52.09° for a 90mm TB..... and the in-between blade angles for the different ID TB's from 60mm to 90mm.

Or 1" pedal travel will cause a 60mm TB to rotate its blade 60.31° and 52.09° for a 90mm TB.... if the pedal to fulcrum to cable hookup dimension is the same, or maintains a 1:1 ratio.

In other (simpler) words..... pressing the accelerator pedal down 1" will cause a 90mm to open less its TB blade when compared to a 65mm or 70mm TB, or any other smaller throttle body for that matter.

[merc91]

if you think 5400rpm is power down low your wrong. 5400 vs 3200 for a 5.0 is a substancial difference in hp peaks just to let you know. if my logic is elementry why didn't you realize it before you posted your calculations based on how much TB an engine needs with completely forgetting about RPMs that the engine has to have the capacity for?

you see, what these guys are getting at is we need low end targeted parts, because our trip up to 5400 rpm for hp peak would take quite a while with a heavy car. even waiting until 3000-4000, for the heavy cars you wanted adressed, for the torque is not what one would call ideal "low end" compared to 2000...
Why would we want to wait until 4000RPM's for your posted lincoln motor's torque when we can get it at 2000? Hense the motor and parts that are chosen and the air capacity they need. Just so happens a 65mm TB provides the air needed to run out low end targeted setup.

5400rpm... did you look it up? do you own one?
I don't recall saying those motors don't make torque, try reading my post again, I said that Fords 5.0's hold their own compared to the other motors in the torque department. Everyone uses 2000rpms driving so why not get your peek there vs 3500 or so?

its quite simple, engines are designed to bring in a certain amount of air, allong with a certain amount of fuel. So a motor buzzing 6000 RPMs would use theoretically twice the air as one buzzing 3000. So a larger TB is needed because the motor is moving twice the air through. So with a 140 CID motor pulling in about 280 CID of 5.0 RPM equivilant air capacity at the peak hp RPM's that THE MOTOR IS DESIGNED TO HAVE THE CAPACITY FOR, the TBs are close to the same size. Displacement has nothing to do with TB size... the amount of air the engine needs at its maximum capacity does. Smaller motor and higher rpm design is around the same CFM as a bigger motor with lower rpm, and TBs sized accordingly.

personally i don't think you can go to big, but your calculations on what a 5.0 should need, comparing to other motors are way off which is the point I was getting at. So if our choice motor's setup for staying under 3800rpms only need so much air, we don't spend all the extra $$$ to allow the ability for more air to go in, that what the engine can take.

If you have some test numbers big vs small on a 5.0 lets see them. It would be very beneficial to myself and others to see the direct comparison.

[Outlaw440]

5400rpm... did you look it up? do you own one?
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If you actually read what i said, i said i did look it up, and it makes PK tq at 3000rpm, like i previously stated. Doesn't sound much like a terd down low if you ask me. And without seeing an actual dyno sheet of the ENTIRE powerband, any accurate statement on your part cannot be made on it.

If you have some test numbers big vs small on a 5.0 lets see them. It would be very beneficial to myself and others to see the direct comparison.

You want an example? fine. Im not going to keep spoon feeding you this crap so im going to give you just one to think about for now.

David Claflin's car (im sure you dont know him)

1990 LX mustang, 306, 92MM Pro-M, 90MM TB, TFS-R intake, Neil Erickson ported Edelbrock performer heads, Custom cam, 1 3/4" longtubes, tuned with a Moates QH, T5, 3.73's, etc. Probably weighs about 3300 since its a fully loaded and non weight reduced car, not far off from a 3800 pound panther.

He rolls through town in 5th gear @ 1300 rpm all day long, and it takes off at the flick of a switch when he drops a gear or two and romps on it. Getting 25-26mpg @ 75mph on the freeway mind you.

He has ZERO driveability problems, enough "low end tq" to scare the piss out of himself, it idles SMOOTH as glass and he drives it every day with factory or better mpgs. What else do you want? Oh i forgot to mention, it dynoed a little over 350hp and 325 ft lbs to the wheels, and runs down the 1/4 in 12 seconds flat on its first run down the track with no adjustments (with proper gearing like 4.10s he'd easily be in the mid-11s. Find me some N/A 302s that make that kind of power with a 65mm TB and a stock intake.

I'll toss Jay allen's car in there also, a custom cam, Super vic intake with an elbow, 90mm TB, longtubes, GT40 heads, custom billet cam that he designed, and 4.30 gears. 11.20s at 119mph.

It's amazing what you can do with the proper matched components.

Could a panther with GT40 heads, a 90mm TB, super vic intake, 1 3/4 primary shortys, proper gearing and a custom cam run bottom 13s-13 flat? If you know how to drive, it'd damn well better. I wouldn't be surprised if you broke into the 12s with such a combo.

[merc91]

yup 5400 is all over google for peak (takes 2 seconds to find that) but looking a little further tells that 6000 is around where she runs out of steam... which is what i'm getting at with where the motor has reached its limit of air it needs. its around 3800-4000 for a panther where it packs it in even though it peaks around 3200 for hp.

3300 and a little closer to 4000lbs are a big enough difference. Throw another 600lbs or so of bricks in a car with a little higher rpm range around 3500 for torque and you will see what were talking about with being a slug off the get go and how much we need that really low torque to get goin.

There cars probably scream up high which is great for them and their setups, and they would definently need a 90mm TB to pass all that air. You obviously need a TB big enough to support the capacity for the motors highest air consumption point. dropping it a gear or 2 and romping on it would be putting the motor in the high rpm range right, thats not low end torque. Once again theres not allot of motor rigs like a 5.0 GT40P setup that can give us that really low end grunt including all the motors you listed in your first post so thats why there popular on here unless you have the coin to get a really nice done up unit like you mentioned with 350 hp at the rear wheels where you wouldn't care where the peak is at because there's power everywhere.

That being said, when i get the money, I will buy a carbed crate motor with the great high flowing heads and matched cam and everything else to match and give me a nice flat torque curve and the high end hp which is great to have for sure.

But in the mean time 250hp at the flywheel and lots of torque around 2 grand is my best option for a affordable cost engine build with GT40P heads and 65mm TB, and other mods to get the most from it.

people might see the first post and think they need a 90-100mm TB to feed their gt40 when they really don't because the maximum amount of air an engine needs at 4000 isn't as much as your calculations say. If you have a 302 running up to 6000 than yes you will obviously need to feed it more air because it needs another 50% over stock.

[merc91]

basically you said a 90mm will work better than a gt40 65mm unit... and that anyone who said otherwise is full of crap. Which it probly will, but how much? I just want to see hp and torque comparisons for both setups on a motor setup that is quite common on here heads and cam wise, not quarter mile times for a 350 rwhp stang.

[Outlaw440]

What do you not understand?

Yes, those cars can turn high rpms. Do they have to? NO. They still make shitloads of power down low. Jay's car spun 7k rpm (went 20k miles before he did something else with it and the motor was still fine) and David's car doesnt run much above 6000rpm. READ what i said, david cruises around at 1300 rpm in 5th gear!! @ 45mph. Yeah, im sure it has no low end.

You say that these cars need more power down low, which is correct. You want to choke the motor off at 4k rpm or whatever just to have more low end? It doesnt work like that.

So you build this motor to make all kinds of steam from 1500-4000rpm, then when you get your merc up to 4000rpm? Then what? Then its a freaking turd because it can't accelerate any further. You can have low end, and top end power you know.

You are not going to sacrifice any low end torque with a 90mm TB, NONE. Get that in your head and think about it. This misconception that you can't have low end and top end power is so idiotic its a joke.

Let me see if i can make this more clear to you.

Do you want a car that makes power from 1500rpm-4000rpm and makes lets say 285 ft lbs @ 2500rpm and 315hp @3800rpm

Or

Do you want a car that makes power from 1500rpm-5700 rpm and makes 300 ft lbs @ 2500rpm and 375hp @5500

If you want to give up power, thats your own decision, but i am not about to advocate that.

There is ZERO sacrifice of low end power with a larger intake and TB with EFI when tuned properly.

[Outlaw440]

basically you said a 90mm will work better than a gt40 65mm unit... and that anyone who said otherwise is full of crap. Which it probly will, but how much? I just want to see hp and torque comparisons for both setups on a motor setup that is quite common on here heads and cam wise, not quarter mile times for a 350 rwhp stang.

I could if i wanted to but i would rather not, you know why?

Because i don't race dynos. I will not race dynos, when you go to the track are dynos running down the lanes or cars?

Jay allen's car by the times he runs on the track calculates to something ridiculous like 450hp at the motor, his car only put 300hp on the dyno. See how useless a dyno is yet?

WTF good are peak hp and tq numbers? The column average=aka the usable powerband is what matters. How important is your famed "low end tq" at less than 2000rpm when you launch at 2000? Then all of a sudden its meaningless.

Dyno sheets that aren't backed up by track times are useless. How quick an engine accelerates is far more important than whatever number it puts down. When you lose a race to an identical car with less of this famed dyno power are you going to use the excuse "oh it made X on a chassis dyno". and thats just what it will be, an excuse.

If you don't want to pay attention to how things work in the real world, thats fine by me, but if you do want to actually sit down, learn, and have an intelligent conversation that is all i am looking for here, and very few seem to have a clue. I commend 1987cp for actually thinking, making intelligent responses, and contributing to some factual discussion.

On other forums i participate in, such as sbftech.com, merc91 you would be canned by now for spreading BS.

Track times, 0-60 times, 0-100 times that show how well the car is accelerating,taking off, holding speed etc. are what really matters. A dyno # at XXXX rpm is almost useless.

I don't race dynos, i will not race dynos, until they start featuring dyno racing in Pro Outlaw 10.5 i will not be building a dyno to bring to Atlanta dragway or Atco raceway next year.

[Lincolnmania]

i cannot read that much info......short attention span, and you are way over my head with all these fancy terms......all i know is that i made 100 rwhp over stock specs untuned and speed density, my car has excellent throttle response, and it gets decent fuel economy, and i still have the fastest 302 n/a townie around........show me what box panthers you have built mang.

[cld783]

thanks for putting me in my place outlaw. runs to get a 130mm throttle body for my HO converted lopo.

i'm gonna have the biggest TB ever, so big the fucker will suck your face off

[merc91]

what your not getting is we all can't afford to put a 450hp motor in these so we use at the highest, gt40P heads for the most part. 90% of these posts your see and are complaining about are directed toward those motors. No-ones saying to put a tiny intake and TB on a 450hp motor for torque if you can afford to build one for a daily driver box panther. Such a motor revving up to 7 grand needs a TB big enough to pull in enough air at 7 grand, one that goes till 4 needs a TB that will pull in the air till 4 grand. Just so happends almost all of these posts on here are about the later motor setup... hense no reccomendations for 90mm TBs. their rarely referring to trying to build a 450 hp motor.

[merc91]

and about me spreading BS... read your first post again and you calculations for how big a HO 5.0's TB needs to be. Thats BS, and you need to figure out how many CFM each motor needs to pull in at its most demanding point, not just CID. Which I did those rough calculations and they turned up that 65mm TB for a HO is what it needs. Theres no problem going over and throwing on a 75 from what I can see.

alrite have your raced a sub 300hp HO or GT40 Box marquis at the track with a 65mm TB then one with a 90mm TB? Since your not a fan of dyno's lets see the quarter mile time difference.

[P72Ford]

-1997 Dodge Caravan 3.3L engine = 56mm bore/55mm blade
55mm/201 C.I.D. = .2736mm per cid = 82.63mm for a 302, 96mm for a 351

Greetings Outlaw440,

I would like to let you know, that whereas you have provided impressive looking information, I can not read any further than the first part of your first post.

There is a problem...

Have you forgotten that the area of an approximately circular region is the function of pi*(radius)^2?

I would say so...

I have chosen the above example of the Dodge Caravan with the 3.3L. Not because I like Dodges, just because... it really isn't that important.

The problem with all of your 'figuring' is that you are using a single dimension linear unit to reason, when you should be using at least a 2 dimension unit. You are making a ratio between throttle body width, and engine displacement, which is absolutely incorrect.

Why is it incorrect? Because, the width of the throttle body tells us nothing, unless we know the shape of the cross section, right? Furthermore, the diameter of a circular cross section s not linearly related to area of the cross section. And, since the aprroximately circular throttle body seems to be the most commonly referenced, I am pointing this out. However, even if you used the width of an arbitrarily shaped cross section, the area would not be linearly related to the width.

At the very least, you should compare the area of the control surface of the throttle body to the engine displacement.

In which case, a 55mm diameter circular control surface has a 2375.8mm^2 area. That is 11.82mm^2/cid of control surface.

By that standard, a 302 Ford would require a 3569.7mm^2 control surface. If you know basic geometry, and you divide by pi, and take the square root, you get the dimater of the circular control surface to be almost 67.41mm.

Not far off from 65mm, eh?

This is only a 2 dimensional comparison. And besides, you are merely comparing one engine to another, which has little value. If you want to do something that matters and makes sense...

You would work out a model of the engine, and figure out exactly how much air it would require. Start with a chemical equation for combustion of gasoline in air... Obviously you don't want a stoichometric equation, because that never occurs in the real world. You'll have to do some research on the more realistic combustion of gasoline in air. But, if you only have carbon dioxide, nitrogen gas, some oxygen and water on the right side, it isn't right. There should be some other nitrogen compounds, unburnt fuels, and also carbon monoxide, at least. Some basic research will tell you the typical molar ratios of what products you'll find in the exhaust. You'll never get an ideal equation, but you'll get close enough...

Then, if you know how much fuel you will be using, in molar quantity (molar mass flow), you can figure out approximately how much air mass flow you need. Then, through some kind of iterative loop (which I am not going to explain), you can reach a consensus on the ideal throttle body width for a given cross sectional area.

Anyways, I just wanted to offer a little of my perspective on this, from my background. Also, this is just the simplest of theory, really. Most important than cross sectional area, any day of the week, is the geometry. If you can increase air velocity with the shape of the throttle body, then the diameter doesn't have to be as large to begin with.

[Outlaw440]

P72ford, would you like me to post up the conversions in Average Cross Sectional Area (ACSA)? Because i have those as well. ACSA is also what real engine builders are using to determine what cylinder heads, intakes are used. I simply kept it 2 dimensional to try to keep it more simple for people to follow along. I beleive you have a fairly good knowledge of math so i may post them in a moment.

what your not getting is we all can't afford to put a 450hp motor in these so we use at the highest, gt40P heads for the most part. 90% of these posts your see and are complaining about are directed toward those motors. No-ones saying to put a tiny intake and TB on a 450hp motor for torque if you can afford to build one for a daily driver box panther. Such a motor revving up to 7 grand needs a TB big enough to pull in enough air at 7 grand, one that goes till 4 needs a TB that will pull in the air till 4 grand. Just so happends almost all of these posts on here are about the later motor setup... hense no reccomendations for 90mm TBs. their rarely referring to trying to build a 450 hp motor.

Oh jesus christ i am about done trying to spoon feed this to you.

Show me ANYWHERE, that i said the motor needs to rev to 7000rpm to take advantage of a larger TB. Jay Allen's car made nowhere near 450hp, he was using GT40 heads for christs sake, it only put 300hp down on a dyno, but when you calculate his track times to hp, it calculates to 450hp or something ridiculous, i was merely pointing out that a dyno is useless if you don't know what you are looking at. Peak hp and tq numbers are garbage, AVERAGE numbers are where it counts.

Pull the budget card as i see you already have, everyone does it, i see it every god damn day, the excuse of money spent always comes up at the track. If you want to use budget pieces, really, congratulations, they are great improvements over stock and if thats what you are looking to build than more power to ya. BUT, when people want to build serious power with efi, that is why i started this post, if you cant grasp something as simple as that then i am done trying to explain this.

and about me spreading BS... read your first post again and you calculations for how big a HO 5.0's TB needs to be. Thats BS, and you need to figure out how many CFM each motor needs to pull in at its most demanding point, not just CID. Which I did those rough calculations and they turned up that 65mm TB for a HO is what it needs. Theres no problem going over and throwing on a 75 from what I can see.

alrite have your raced a sub 300hp HO or GT40 Box marquis at the track with a 65mm TB then one with a 90mm TB? Since your not a fan of dyno's lets see the quarter mile time difference.

I am not a fan of dynos. The guy who puts together the vast majority of my engines is not a fan of dynos, the guy who designed the camshaft in 3 of my vehicles is not a fan of dynos, do i need to go on? This crap was explained to me years ago and i am just trying to pass it on.

And no, i haven't raced a box marquis, but i am fairly confident a 4300 pound truck qualifies as racing something heavy. Maybe i will build a panther someday for shits and giggles, but as of now there is no reason for me to do so, there is no NMRA class that i beleive it would fit into competitively. I build cars to win races, not to lose, if i feel it wont win races, im not going to bother. I have a hard time beleiving a 3800 pound box panther can be trimmed down to 3200 pounds to meet 25.2 SFI chassis specs.