Mid Output Intake Question

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Mid Output Intake Question

November 01, 2018, 08:33:43 AM

Hey guys,

I picked up a nice 5.0/AOD combo from 50RACER last weekend. He's a cool dude and very helpful!

I am planning my transplant around the "Mid Output" 5.0 mod from coolcats.net. The upgrade parts I have acquired thus far that I plan to swap onto the motor are:

Rebuilt GT40P heads

Foxbody Mustang 5.0 Headers

My plan is to use a 87-93 HO upper intake plenum and 60mm throttle body/EGR spacer. I was browsing CL and found someone selling an explorer upper and lower intakes for a very reasonable price. My questions is, am I going to run into a problem with too much airflow for the amount of fuel I'm dumping in with the stock computer/injectors? If so, should I stick with the HO intake/TB and call it a day? I'm not trying to get major horsepower out of this car, just making it a little more fun to drive without spending too much money.

Thanks!

Mid Output Intake Question

Reply #1 – November 01, 2018, 10:39:38 AM

I've run several "mid output" setups over the years utilizing stock injectors and stock ECU. Most using the speed density injection as found on the 88-earlier 5.0 Birds and all the 5.0 Mk7s. The stock injectors, if in good operating condition will suffice for your parts list.

With the exception of the in-tank fuel pumps, Ford has traditionally designed their fuel systems with a fairly wide margin of additional capability. Putting another 35-50 HP thru it is well within the fuel system and the ECU's abilities to compensate for it with the caveat that you should make a Walbro 190 or 255lph pump a part of your upgrades.

Mid Output Intake Question

Reply #2 – November 01, 2018, 11:27:50 AM

So more fuel supply from an aftermarket pump would be good enough to allow me to run the GT40 intakes no problem? Are there any other mods you recommend for this mid output setup?

Mid Output Intake Question

Reply #3 – November 01, 2018, 01:23:29 PM

If you're going to have the car completely apart to redo the heads you might as well do the camshaft while you're at it

Mid Output Intake Question

Reply #4 – November 01, 2018, 01:41:55 PM

Its not so much that its supplying any extra fuel at the motor at a given time, as it is ensuring that the pump is delivering an adequate supply of fuel(and at pressure) to the injectors, all 8, all the time. On a stock 150 horse Tbird V8, even with some age on it, the wimpy stock pump will probably keep up. The motor is essentially dead at anything above 4800 rpm as far as power making goes, anyhow. Once you do an HO swap, and then improve on that, with ported heads, explorer/cobra intakes, exhaust, etc, the stock pump should not be expected or relied on to bring the fuel to the party. The stock injectors may be perfectly capable of doing the job but if the pump cant put the required amount of fuel (and at pressure) up to them, its not the injector's fault.

I'd suggest bolt down 1.7 ratio roller rockers if youre using any of the Explorer/GT40 or stock E7 HO heads. Leave the stock HO cam in it, install a good roller timing chain set if the stock one one hasnt been replaced yet.

Common 1 5/8" shorty headers and bolt on 2.5" H pipe are sufficient for most 302's not using power adders. If you are going to use a small dose of nitrous later on, full length headers would then be worth considering instead of shortys.

Plan on needed AOD transmission upgrades or a T5 5 speed swap if you are going to go much further with power upgrades, or plan to run it hard at the track very often.

Mid Output Intake Question

Reply #5 – November 01, 2018, 03:47:35 PM

If you're gonna do heads and intake, and have the time/ability, I'd throw in an HO cam. Those heads will need something other than the stock springs, and if you're going to replace the cam, new timing set and oil pump.

I did basically the same thing, except I started with a low mileage HO engine. E cam, P heads with trick flow springs, Cobra intake, BBK shorties, Exploder 65mm TB and the usual stuff. Runs great. I also slapped in a Walbro 255 pound/hour fuel pump. Probably a little overkill for the current stuff, but if I decide to throw a blower on later or even nitrous, I'm sorta in good shape.

I'm running 24# injectors, but in your case, unless you go with a cam more than HO specs, the 19's will suffice. Is your engine the SO from a Tbird? Reason I ask, the SO engines had pistons that did NOT have valve reliefs. If you put a higher lift cam in (an HO will not cause issues), you will likely run into some PtV issues (piston to valve). As mentioned, an HO cam will work with stock SO piston however.

You can build or buy nice AOD trans that will handle HO power levels, the stocker probably will be ok if it's been taken care of, good fluid, etc. If you're gonna beat on it (why not, right?) it won't last.

If you can or haven't already, 3.73 gears will make an AOD car pull pretty good, 4.10s would be better.

I've been thinking myself about an AODE and a standalone for my Mustang. Take more power than a T5. I've already broken 3 of 'em. With Nitto tires though, it ain't hard to..

Mid Output Intake Question

Reply #6 – November 02, 2018, 09:34:06 AM

I understand that while I have the motor out of the car it would be relatively easy to do a cam swap. The reason I am trying to avoid it is because at that point I need to start worrying about whether or not my trans is strong enough and I would need to deal with swapping out the stock springs on my heads. The idea behind this project is to use the parts I have and take my SO motor to “mid output” levels. I have no intentions of drag racing or even driving very fast. I’d just like a little more get up and go. The current plan is:

Swap stock upper and lower intakes for GT40 units

Swap throttle body and EGR spacer for 60mm HO units

Swap E6 heads for rebuilt GT40P heads

Swap stock fuel pump for higher capacity Walbro unit

Swap cast iron exhaust manifolds for HO headers

Anything else I should be considering?

Mid Output Intake Question

Reply #7 – November 02, 2018, 12:04:46 PM

The combo you have laid out absolutely will not run correctly with the stock speed density Tbird computer. With all of the modifications you are planning you are so close to going 100% with a better than stock Ho set up. When I first started my conversion I ran the same combo that you were describing with the only difference being a speed density HO camshaft with the HO speed density computer. Back then people nearly gave this stuff away, you might be lucky enough to find these two additional items for nearly free. You won’t need to change the valve springs on the GT 40 P heads but a lot of people recommend it.

Mid Output Intake Question

Reply #8 – November 02, 2018, 04:37:43 PM

I'm not sure if I have any more HO cams, but if I find one, it's yours for shipping cost..?

You may as well, then grab yourself an SD1 or equivalent speed density EEC and you're good to go with the above stuff. It's actually well worth it. With an HO cam though, I would recommend upgrading the valve springs on the P heads. The explorer cam didn't have the lift that the HO units do, and those P springs on the wimpy side.

(as an aside, my '98 Explorer runs outta steam before 5 grand...my Mustang...does not LOL)

Mid Output Intake Question

Reply #9 – November 02, 2018, 07:38:12 PM

Ok, firstly, reading comprehension owned me when I read the OP. Apologies. I thought you had bought an HO motor and were improving that, so my bad for replying without reading more carefully.

Anyhow, the P heads have a different spark plug angle that will cause contact between the stock HO headers and the plug wire boots. I've heard where people have used a combination of a special shorter spark plug and plug wires with 90 degree boots to keep them from melting against the headers and to fascilitate spark plug removal that doesnt require unbolting the header to get a socket on the plug.

Ford racing makes the P specific shorty headers and people report that some of the aftermarket long tube headers have better clearance for the GT40 P head spark plug angle. You will want to get that sorted out to save hassle later.

Truthfully, I'm not of the opinion that making head and intake improvements is worthwhile if its going to eventually be piped thru stock HO headers. The stock HO heads and intake do not run out of lung until around 5200rpm on a basically stock 302. The Explorer intake only starts to offer a significant comparative advantage past this area of engine speed. Which happens to be the same rpm area where the stock HO headers become more restrictive. Adding additional airflow/fuel to create more power and thus, creating, by effect, more exhaust is not going to make the stock headers any better at what they are doing. My guess would be disappointing or very marginal gains over what a regular HO swap would bring. Just my $.02.

Mid Output Intake Question

Reply #10 – November 02, 2018, 08:48:15 PM

I skimmed over the stock header part. The opening of them is smaller than the actual exhaust port on the gt40p head. Decent headers can be had on ebay for $60-$70.

To the OP again, you ask about to much air for the stock computer and injectors. Its absolutely too much and will run lean. Even with the upgrades stated on a speed density computer you are still going to want an adjustable fuel pressure regulator and bump up the pressure to compensate for what the computer wont be able too.

Mid Output Intake Question

Reply #11 – November 02, 2018, 10:08:43 PM

Speed density doesn't like change in volumetric efficiency without tuning that table. More information on that here

http://support.moates.net/theory-speed-density/

Also if your AOD is in decent condition what you're planning to run on it should be ok when you go to adjust your TV Cable just pull it slightly tighter you will have a little longer and harder shifts but it keeps the pressure up. I've run the stock AOD in mine with countless 150 shots of nitrous and lately 10 psi plus nitrous. I'm sure it will give up the ghost someday but not today and it's held on for over a year still shifting great.

Mid Output Intake Question

Reply #12 – November 03, 2018, 07:35:53 AM

I agree with others on the cam swap while you’re into it that far. If the Explorer intake is within your budget I say get that also. An Explorer TB can be converted to work as well I think? Check your local Craigslist and the Mustang forums. You may find what you need there. Good luck and keep us posted
I like the sound of the Ford B cam but I don’t think the SO pistons will allow it and it would require switching to MAF. Although a member on here is running 1 currently.

Mid Output Intake Question

Reply #13 – November 03, 2018, 09:37:12 AM

No worries about the misinterpretations. I appreciate all of the insight. I think most folks opt for doing a full HO setup when they are in the position I am in, and I understand that it's not a huge stretch to take my build in that direction. As CougarSE and ThunderbirdSport302 mentioned, all I would need is a speed density EEC and an HO cam. My reservations about going this route are:

A) I'm hesitant about sticking in a used camshaft. If I opt for a new one I imagine I'll be spending at least $150 on a stock spec roller cam.

B) I'd still have to go out and get new roller rockers and pushrods regardless of whether I go used or new on the cam. Add another $150 and time to the budget?

So, I'm not ruling it completely out but you can see where my reservations are. CougarSE, you mentioned that the stock computer couldn't handle these mods. Which mods do you think are taking it over the edge and what do you think could be scaled back to make it work?

Mid Output Intake Question

Reply #14 – November 03, 2018, 11:42:45 AM

To address A), if it helps put your mind at ease, I've taken the exact same HO cam that I pulled out of my 88 GT probably around a hundred years ago and installed it another 4 motors, that all eventually evolved over time from mid output to high output to super??high output when they got HCI and stroker internals. So yeah that poor HO cam got around, alot. The factory HO cams, in addition to being good performers, are very durable and rarely are damaged unless there is a failure of the oiling system or an equally rare failure of the stock roller lifters. It just doesnt happen often at all.

For B), the standard output 5.0 has the gray 14lb/hr injectors and the standard output ECU is running the car on an assumed injector flowrate of 14lb/hr. So all of its fuel calc's will be off if an injector with a diff flowrate is installed. Same goes for the Mustang or Mk7 speed density ECU, you're pretty much locked into using the 19lb/hr injector with it.

To put it bluntly, the explorer heads and intake are a waste of time to install if the standard output cam, injectors and ECU are utilized. If the budget or labor are getting in the way of swapping these items and adding a good fuel pump, its better to wait until they can be sourced and added to the build.