Best Style GT-40 Lower Intake For Stock 5.0L

[ttocs]

The price they are getting for 94/95 cobra intakes the past few years has just amazed me. Makes me glad I got mine well over 10 yrs ago.

 

[Terrorist 5.0]

The price they are getting for 94/95 cobra intakes the past few years has just amazed me. Makes me glad I got mine well over 10 yrs ago.

Absolutely. Buying one is going to hurt, but, I’m sure it will retain value for the most part, not that it matters because I would likely keep it.

 

[shovel]

If you're buying the Cobra setup for the fit/appearance (vs. other performance options, anything's better than stock H.O.) and keeping the E7 heads I can't imagine the difference in any of them will be of much consequence. Who are you racing anyway are you gonna go show your taillights to people in Lucids and Plaids? Or just enjoy driving a classic car.

Less thinking more driving

 

[Terrorist 5.0]

If you're buying the Cobra setup for the fit/appearance (vs. other performance options, anything's better than stock H.O.) and keeping the E7 heads I can't imagine the difference in any of them will be of much consequence. Who are you racing anyway are you gonna go show your taillights to people in Lucids and Plaids? Or just enjoy driving a classic car.

Less thinking more driving

It's caught my curiosity and wanna figure out how an intake that way outflows the head make more power, ALLEGEDLY without sacrificing any low end, and it's affect on the torque curve. Plus more doesn't hurt does it? If I'm not wrong, nobody has ever definitively documented it, and I went really deep into the forums. Would be nice to have a solid answer for others. It's all good learning anyway.

 

[shovel]

The reason an intake which outflows the head can still make power is likely going to be in part because of the consistency between cylinders (as in that video I put on youtube) and in part because flow standardized to 28" water does not equate to actual dynamic flow which is much too complicated to describe in a paragraph of text.

Example when your 4" diameter piston is being pulled down at 10 meters/second while your 1.78" diameter valve is just starting to open up there's pretty much a full bar of pressure differential there which means those first air molecules are traveling at the speed of sound or close enough to it. By the time crank angle gets to ~75 degrees the piston is going 2.5x as fast and in that instant the piston is leaving behind a void which is geometrically ~1700 cubic feet per minute.

So if we took a 302's geometric displacement and run it at 6000 rpm completely ignoring air's viscosity, mass, inertia, surface friction, etc the cylinder wants to eat 65 cubic feet per minute which means a 1.8" intake runner would see an average air speed of about 9-10 mph.

In reality it's never going that speed because valve events, cam profiles, changes in piston velocity throughout its stroke, constantly changing air pressure (reynolds value). It's coming to a dead stop 3000 times per minute and some portion of it is accelerating to >300mph between those stops. None of us is equipped to do the CFD analysis but we all know the difference between putting your hand out the window to feel the air at 9-10mph and at highway speeds.

Probably also worth mentioning that airflow standardized to 28" water means the pressure differential is about 1psi on the other side so if you're at sea level and pull 200cfm through a fixture rated at 200cfm at 28" you're down to 0.94 bar (13.7psi) where measured. In other words when you say something flows X cubic feet per minute it's implied that you accept -1psi by the time you've achieved that much flow. If people standardizing flow to 28" would also measure ~4" that would represent ~1% pressure loss which is still arbitrary but a lot closer to zero than 28". I suspect that kind of measurement would reveal a greater difference among different manifold assemblies.

That's a lot of numbers and they matter if you're engineering something from nothing but if the intake you can find used for sale in your price range was manufactured 30 years ago it was already engineered by people who did that math and convinced their accountants that a 25 pound chunk of cast aluminum was a good idea so the best you can hope to do is either buy some dyno time to answer the burning question or bolt it on and let the mystery remain.

I'm running 3.08 gears and no intention of changing them, if I lost any torques at all I sure didn't miss them when they left. At this time I have the 94/95 Cobra manifold (believed to be both upper and lower, they were a set when purchased and no difference in visual appearance of surface) along with stock cam, 1.72 rockers, stock heads, ford performance exhaust manifolds, bbk catted midpipe and dronemaster drone40 delta-drone 2.5" catback. I'm running 24lb injectors and a pimpX ecu with deleted maf and dual widebands, egr and evap active. Due to situations unrelated to cars I haven't had the time or motivation to get it absolutely dialed in lately so it still cold idles poorly but driveability when warm is awesome and never feels anemic.

 

[joemomma]

For the price difference, Explorer is the way to go unless you're looking for the "look" of the Cobra upper or an all-out balls to the wall NA build. As for gears - it's generally recommended to go two steps for the cost involved. You won't notice much difference in the 3.08 going to a 3.31.

 

[Terrorist 5.0]

For the price difference, Explorer is the way to go unless you're looking for the "look" of the Cobra upper or an all-out balls to the wall NA build. As for gears - it's generally recommended to go two steps for the cost involved. You won't notice much difference in the 3.08 going to a 3.31.

It's the cruising RPM's for me, as well as the already short 1st gear. Even the best geared Camaro of the time had a total torque multiplication of mid 9's, with 3.08's and a 3.35 first gear, you're nearing mid 10's. I would say gearing isn't the issue with these cars, it's lack of power.

 

[RAU03MACH]

1986-1993 Ford Mustang 5.0L Polished Tubular Cobra Intake Manifold GT40 302 GTLX | eBay

Very nice used 1986-1993 Ford Mustang 5.0L Tubular Cobra Intake manifold 302 GT40 EFI. Very nice polished upper, lower and plaque. We use the most economical carriers for you depending on the item & your location.

www.ebay.com

 

[RAU03MACH]

still the best for 5.0

 

[Terrorist 5.0]

still the best for 5.0

Best for going broke lmao, overrated in my opinion.

 

[RAU03MACH]

i did not pay that much for mine
i paid 600 a long time ago when ford came out with that intake
mine is pretty much a classic 1 owner

 

[Terrorist 5.0]

i did not pay that much for mine
i paid 600 a long time ago when ford came out with that intake
mine is pretty much a classic 1 owner

Now they are a rarity though. They look amazing and probably save weight, but no way. Too much nowadays.

 

[RAU03MACH]

 

[RAU03MACH]

i am going to sell this engine once i get my 351 roller motor done
i just need time to build it
and not have any more misshapes

 

[Terrorist 5.0]

The reason an intake which outflows the head can still make power is likely going to be in part because of the consistency between cylinders (as in that video I put on youtube) and in part because flow standardized to 28" water does not equate to actual dynamic flow which is much too complicated to describe in a paragraph of text.

Example when your 4" diameter piston is being pulled down at 10 meters/second while your 1.78" diameter valve is just starting to open up there's pretty much a full bar of pressure differential there which means those first air molecules are traveling at the speed of sound or close enough to it. By the time crank angle gets to ~75 degrees the piston is going 2.5x as fast and in that instant the piston is leaving behind a void which is geometrically ~1700 cubic feet per minute.

So if we took a 302's geometric displacement and run it at 6000 rpm completely ignoring air's viscosity, mass, inertia, surface friction, etc the cylinder wants to eat 65 cubic feet per minute which means a 1.8" intake runner would see an average air speed of about 9-10 mph.

In reality it's never going that speed because valve events, cam profiles, changes in piston velocity throughout its stroke, constantly changing air pressure (reynolds value). It's coming to a dead stop 3000 times per minute and some portion of it is accelerating to >300mph between those stops. None of us is equipped to do the CFD analysis but we all know the difference between putting your hand out the window to feel the air at 9-10mph and at highway speeds.

Probably also worth mentioning that airflow standardized to 28" water means the pressure differential is about 1psi on the other side so if you're at sea level and pull 200cfm through a fixture rated at 200cfm at 28" you're down to 0.94 bar (13.7psi) where measured. In other words when you say something flows X cubic feet per minute it's implied that you accept -1psi by the time you've achieved that much flow. If people standardizing flow to 28" would also measure ~4" that would represent ~1% pressure loss which is still arbitrary but a lot closer to zero than 28". I suspect that kind of measurement would reveal a greater difference among different manifold assemblies.

That's a lot of numbers and they matter if you're engineering something from nothing but if the intake you can find used for sale in your price range was manufactured 30 years ago it was already engineered by people who did that math and convinced their accountants that a 25 pound chunk of cast aluminum was a good idea so the best you can hope to do is either buy some dyno time to answer the burning question or bolt it on and let the mystery remain.

I'm running 3.08 gears and no intention of changing them, if I lost any torques at all I sure didn't miss them when they left. At this time I have the 94/95 Cobra manifold (believed to be both upper and lower, they were a set when purchased and no difference in visual appearance of surface) along with stock cam, 1.72 rockers, stock heads, ford performance exhaust manifolds, bbk catted midpipe and dronemaster drone40 delta-drone 2.5" catback. I'm running 24lb injectors and a pimpX ecu with deleted maf and dual widebands, egr and evap active. Due to situations unrelated to cars I haven't had the time or motivation to get it absolutely dialed in lately so it still cold idles poorly but driveability when warm is awesome and never feels anemic.

Just saw you're video and wanna say that I watched your acceleration clips. Impressive, your car runs pretty good, and I burst out laughing at the end when you were talking something about dreading finding the results of and finishing a project and not wanting rejection of doing it badly. With the emphasis and the way you looked at the camera, my mind came right back here to my rambling curiosity and I had a great laugh. Awesome video as always.

 

[96blak54]

Runner shape and the characteristics of air as it moves thru said runners affect how the end results are before entry to the heads port. Any curve or bend the air moves through within the port needs to be flat inorder to maximize the coanda affect. In other words air streaming through a given area wants to move straight and doesnt like to bend. Air must use itself to bend. As the stream moves over a flat bend/radius, turbulence is created under that stream and will pull that stream into a new direction.

This can easily be seen with the evolution of all the mustang intake manifolds. Start with the 5.0l manifolds and investigate their runner shape and port shape. Look at the aftermarkets and youll see the aftermarket manifolds had it figured out over the stock. The round tube cobra manifold in my opinion is the worst example (slightly better than stock) Move on to the early 4.6l manifold and then to the npi 2v and then to the pi manifold. The pi manifold hands down is a perfect example of exactly what im referencing to.

So with all that said, if youll keep in mind of air stream characteristics within walls while you perform your work, im sure youll achieve your goals.

 

[Rod]

Look up Richard Holdener on Youtube. He did a GT40 intake shootout. There is negligable differences in the flows of any GT40 variant. That said pick up an Explorer intake and but an Edelbrock or T/F elbow for the TB and you get the performance gain but cheaper than the Corba variant. If the smooth look is what you want get the Cobra version. All in all you won't notice much of any gain with the stock heads, but you may possibly feel some low end torque losses.

 

[Mustang5L5]

I still have the receipt from when i bought my 1993 Cobra intake from Summit Racing back in the day. I paid $399 for it.


Sounds like a deal but when i plug that into the inflation calculator it's $710 in today's money.

 

[shovel]

A lot of the recorded tests whether they're in 1990s magazine clippings or on youtube showing dyno charts or quoting horsepower numbers are doing that with aftermarket heads that ask for a lot more air than E7's and except for bread box intakes they all only vary the location of the torque peak by 100-300 rpm.

 

[ttocs]

I am sure I know the answer, but wanted to ask since they look so similar. The 351 gt40/lightning lower is different from the 302 gt40 lower right?