I am getting ready to swap in a set of gt-40 heads into my 88f150 302. I found a good deal on an edelbrock intake(Edelbrock 3841 - Edelbrock Performer 5.0 EFI Truck Intake Manifolds - summitracing.com) and bbk throttle body. I have been reading that the stock 5.0 intakes are plenty good performance wise, but the 5.8's are a different story.

Can anyone tell me it would be worth the investment to put on an intake like this, or is the stock good enough, its not worth the money?


Any info appreciated
thanks,
Josh

 

Not worth the money IMO, the stock 5.0 truck intake easily outflows the stock or GT40 heads, if you actually want to produce better truck power you want a smaller intake like the 5.0HO.. not something even larger like the Edelbrock.

 

the passages on the stock truck are too long and narrow to flow much past 4500 rpm. which is why they did em that way - torque at lower rpm vs the car one. you can use the car upper/lower and the car TB but you have a narrow application range as the cars went mass air rather quickly after 1986 and the trucks stayed speed density to 92ish.

You can pay for the truck mass air update, or get a mustang ECM and use TWeecer to set in your axle ratio and shift points. I saw a web article somewhere about which mustange ECMs are the best adaptable.

btw - this does imply that your effort is for naught if you do not go mass air or TWEEC the stock ECM. Speed density just wont appreciate all you have done to the motor. (some people swear by tweecing, I swear by actualyl measuring airflow)

 

I'm not trying to be nasty here but.... you don't know what you are talking about. In dyno tests the truck intake makes more HP than any of the car intakes, that means it flows more air. The total difference in runner length betwen the truck and HO intake is 1/2". In stock trim The 5.0HO makes more TQ and HP than the truck motor, and all of it happens below 4500rpm.. so the HO intake is better suited to stock or near stock 5.0 motor, regardless what vehicle it is in.


The EFI type has nothing to do with where the powerband develops, the cam determines it for the most part, and the intake messages the shape of the curves with it's runner length and volume.

It is well established that there absolutely no need to convert to mass air for this type upgrade, the computer will supply more fuel to the additional air with feedback from the O2 sensor in closed loop mode. The SD system is more than capable of adapting to airflow upgrades all the way to the injector fueling limits near 300hp.

 

to be frank - no, it does not. Truck vs car intakes were flow benched 20 years ago and the matter is well settled. Furthermore, the round port intakes in better GT motors have far less turbulence. but dont take my word for it, listen to Jon Bennet who is the current multi world record holder and winningest Mustang racer in history, whose company Bennet Racing, I have demo'd CNC machinery and techniques to to build this stuff. Truck intakes, when doing a performance rebuild like many of use have done, are useful for rode anchors for your boat. And scrap. with the price of aluminum they are actually worth a few bucks now. Please note, that in Bennets extensive 302-sourced catalog, there exists not a SINGLE truck intake. But there are plenty of car intakes.

Rubbish. To get any power - real power, not 220 or 230hp from a 302 you are going to have to move the torque peak up at least 1500 rpm (which a truck intake CANNOT do no matter what size dremel you think you have) and get the total rpm peak over turnover, which of course happens at 5252 rpm. this is well documented in any literature from FMS.

yes it does. this is a red herring. Speed density has the fuel map and spark map tables set in stone based on a GUESS of a 9:1 compression motor pulling in air at a certain Volumetric efficiency, at a certain temp and a certain MAP reading at a certain TPS reading at so and so RPM. At most you will see 15-20hp - AT MOST without a remap (hence the repeated use of the word tweecer Again, this stuff is well settled over 20 years now. Once you remap then you can make power and enjoy overbores, larger cams and gt40 intakes. But as I said, some of us prefer actually measuring the air injected and getting an exact reading at real time without the trial and error of a remap.

Another red herring, at WOT the O2S data is discarded as it runs overfueled and will never be in stoichiometric balance. WOT is where power is made.
There is no need if you remap the ECM as I have stated now a number of times. Please read up on the technology, its not all that new and its not all that slick. From the website:

How are you going to adjsut for ANY of this stuff without a remap? I for example run my 302s as 347's, with the heads I run and the cams I run, my volumetric efficiency is completely off. A stock s/d ECM will just give this a blank stare.

(for further example, there is a baffle in your air box that nobody changes which resticts 30% of your possible airflow, and your tranny will shift long before you hit the power band of any of those mods.)

How much power will your 302 make? I have only been spouting this relationship for 30 years now:

HP = Atmos. Press. x CR x VE x CID x RPM ÷ 5252 ÷ 150.8
which is the same as saying Torque = AP x CR * VE * CID / 150.8

which of course implies that Torque is FIXED by the engine componentry. therefore the fuel and spark map are also FIXED by the engine componentry.

Re-read this over and over until it is perfectly clear and well understood. You will not be able to proceed without a firm grasp on the material.

And in a real world example, if I want a 347 to make 370hp (which is a perfectly valid target for not-that-expensive parts) at 6500rpm, I need 300ftlbs at 6500rpm. that is more torque than your engine makes at its old peak

If I want to make a 302 develop a reasonable 290 hp at 5500 rpm using an e303 cam and 19lb hr injectors, you need 277ft lb at 5500rpm - which is what you used to have around 2500rpm. Do you think a stock EECIV ECM with a max fuel value of 5000rpm is going to get you there?

and if you want the same hp at 5000rpm you need 304ft at 5000 which face it, aint NEVER gonna happen naturally aspirated and if you COULD use heads and cams to get you there, the MAP vs temp vs throttle vs RPM table wont even be close, (likely by 40% or more off)

 

It's clear you have done some engine tuning.. or at least read about it. But what you fail to realize is that what works well for a 5.0 in a 3000lb mustang is no good at all for a 4500lb truck. Moving the TQ peak up 1500rpm is completely useless for a heavy vehicle with an 800rpm stall converter and fuel milage gearing. There are numerous people on this site that have swapped complete GT40 top ends onto either a truck motor or a HO, and they all get the same results.. a peaky motor that is absolutely gutless below 3000rpm.

BTW... were do you think Holley got the design for their car intake..

 

A re-tune is always going to be better, but a decent improvement can be made without a re-tune. Where did this come from? None of the units match or make any reasonable sense, and there's no way in the world you can predict power or torque based on engine displacement, VE, CR and RPM. You might be good at tuning engines, but if you think you that formula gives you a "firm grasp" on engine theory, you might need to think again. Show me how to work that formula to get the 850 horsepower we get out of 358 cubic inches in Nascar...

There's also more to an intake manifold than how much if flows on a bench. Ford computers use long term fuel trims from O2 sensor feedback even in open loop situations such as WOT.

 

Are you serious? this dates back to engineering handbooks of the 30's.

For a park ignited engine, if you know the fixed units (CID, CR) and can measure the RPM dependant ones (VE) and know where you are at at the time (AP) then yes, torque is known. the unifying constant (150.8) takes care of any noise. and of course you know that HP = T * RPM/5252, which you can see is IN the equation.

Google it up please, read a little and report your findings back.

Work it yourself. 850 hp only occurs on non-restictor engines at 8000 or 8500 rpm, CR is fixed at a maximum by nascar. If you have the actual HP curve you can work it backwards to discover the VE curve for the engine and learn why Cup cylinder heads are about $50000 a set(This is what the CNC machinery did, digitized a good set and copied them over and over instead of using high school kids with die grinders and dremels)

As you can see, the naturally aspirated volumetric efficiency is the key. IIRC eledbrocks site publishes (or used to publish) a halfway decent tech section on pulse charging. You do know what that is right? If not you need to google THAT up and read on it. (hint: air has mass)

suffice to say, formulas that give HPfor an engine are old hat and about spot on assuming your measurements are there. You can also estimate your HP based on your trap speed if you know your vehicles weight.

Well if we are talking 'does it bolt up' then this is true. Intake mainfolds serve no other purpose otherwise. If they do not flow right for the application it will be crap. If you dont beleive me, bolt a torker II on grannys daily driver and report back.

they do? you will have to show me in the tech spec where this is stated. Im just not seeing it. I didnt say open loop, I said WOT. That stands for wide open throttle. When at WOT you either overfuel, or you do nothing. So if you are overfueled, tell me exactly WHAT is being adjusted or trimmed? overfueled vs REALLY overfueled?

 

Edelbrock.com - Tech Center - Tech Discussion

 

Since you are so proud of your "engineering formula" work the numbers and show me it works. Just punching in some random numbers for the Nascar engines gives 621. Again, none of the units match or divide out or anything. No where in my Engineering Fundamentals of the Internal Combustion Engines text book do I find any formula resembling what you posted above.

You might also be surprised that even with CNC's doing the majority of the cylinder head port work, there are still plenty of those old "high schoolers with die grinders" massaging the heads and intake manifolds in Nascar engines. VE on our engines goes above 100% in a small range of the powerband, normally aspirated. You aren't going to tell me anything I don't already know about Nascar engines, I work with them every day. Show me that your formula works - I'll even give you some numbers to use.

What I meant when I said there is more to an intake manifold than how much it flows was that the runner lengths and cross sections can be tuned for particular RPM bands based on pressure waves created by the air flow into the chamber. Likewise exhaust runner length and diameter can do the same.

I don't have any data to show you about the fuel trims in the computer, but I believe it was in Ford Fuel Injection and Electronic Control by Probst. Open loop is by definition when the computer ignores the O2 sensor input, which occurs at WOT. The long term fuel trim, which is the result of an overall shift in A/F ratio over a long period of time does apply to all operating conditions, including cold startup and WOT open loop situations, while the short term fuel trim only applies when in closed loop control. The computer doesn't just see WOT and says go hog wild on the fuel. It does go slightly rich, which is where the maximum cylinder pressures occur and maximum power occurs. If the computer notices an overall shift in A/F ratio over a long time, it applies it equally everywhere.

 

here: read carefully and take your time. that was simply the first result out of over a million returned by googling. C'mon, this aint that hard and not that hidden.

well in nascar it has be to be over 100% for the ENTIRE powerband. Read, understand, and you will see why.

Well im skeptical your boss will let his VE numbers get published, but go ahead, send them and we will work the hp curve, can even put it in a spreadsheet.

In other words, how it flows. Did you understand what I meant when I said to put a torker II on your grandmothers car?


So you are agreeing that O2S data is discarded at WOT. which is what I said without qualification so I see no issue.

maximum injector bandwidth with a 12:1 or 12.5:1 stoich is 'slightly rich'? Some might argue that this condition could be summed up as 'going hog wild on the fuel'

 

Eric... This yahoo clearly knows just enough to be dangerous, he has posted enough misleading and incorrect info that speaks for itself, no need to feed the troll further. If he want's to join the community and gain some respect maybe he'll start by publishing his full name in his signature.

 

sure thing 'Paul O'....

I note, that neither of you have actually shown anything I have posted to be misleading or incorrect, but that has not stopped ad hominem posts (which I also note are against forum rules)

I have given you both everywhere to look that you need to get started, and I note that has not happened. I cant force you to read up on the subject. So continue to post platitudes like 'the truck intake outflows the gt40 intake' and see how far you get with people that take things seriously.

 

It wouldn't do any good, you would ignore it anyway like you did with the runner length measurements I posted...

 

And pray tell what does that runner length measurement have anything to do with it? I said the truck intakes were longer and thinner (and also said WHY). You posted a number that said they were longer....um...duh. I just said that.

Asking again: did you actually READ any of the info or links I gave you? since you have used the words 'misleading' and 'incorrect', the onus is now on you to show what is misleading or incorrect. not gonna do your work for you.