Maf Performance Enhancements For .40 Over 302.

Bobs88lsc

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Jan 23, 2016
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I had an 84 mark 7. I had the stock block cylinders bored .40 over. I also had the head and valves ported out for better air flow.i have new pistons& new crank
I had this motor set up for a carb,but decided to strip all the carb related parts off the engine (including removal if the cam) i now have an 88 mK 7 LSC. I will be pulling the stock 5.0 HO motor to put the better motor in. I,m wondering what can would be best (e 303?) To run with MAF. Also, I need some feedback on enhancing performance. I know I can run a better MAF set up (not sure what size injections are with the SEFI for the 88). I plan on installing the motor in march. I also have a balanced drive shaft, killer custom tranny (built by a former FVC member with a hardend,input shaft, Kevlar bands ect and. 2200lb stall torque converter ). Also need info on best set of street/ highway gears for the 8.8 rear end. ANY feedback would be helpful.thanks.
 
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stykthyn

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Before any of those are addressed what is your goal for the car?
 

jrichker

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You won't get 400 HP out of a 5.0 block without a max output stroker 347 engine, or NO2 or pressurized induction.

NA without a power adder, 325-340 FLYWHEEL HP is all you can hope for with a .040 overbore and stock stroke that is primarily a street/strip car. You might make more, but the engine will lack good street manners and probably have some idle problems. Stalling at stoplights because the engine won't idle smoothly is a major headache. The auto trans can make the problem worse unless you put the trans in Neutral every time you stop.

To get that 325-340 FLYWHEEL HP you'll need some excellent aftermarket aluminum heads, (Trick Flow or AFR) aftermarket intake manifold , something other than a Ford letter cam, 24 lb. injectors, 75 MM MAF, 65 MM throttle body, 155 LHP fuel pump. Ford Racing headers and a custom dyno tune.

If you don't have $2500-$3000 for new parts, you will never reach your goals.


You have an auto trans, so you will need 3.73 or 4.11 rear axle gears
 

Bobs88lsc

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Jan 23, 2016
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You won't get 400 HP out of a 5.0 block without a max output stroker 347 engine, or NO2 or pressurized induction.

NA without a power adder, 325-340 FLYWHEEL HP is all you can hope for with a .040 overbore and stock stroke that is primarily a street/strip car. You might make more, but the engine will lack good street manners and probably have some idle problems. Stalling at stoplights because the engine won't idle smoothly is a major headache. The auto trans can make the problem worse unless you put the trans in Neutral every time you stop.

To get that 325-340 FLYWHEEL HP you'll need some excellent aftermarket aluminum heads, (Trick Flow or AFR) aftermarket intake manifold , something other than a Ford letter cam, 24 lb. injectors, 75 MM MAF, 65 MM throttle body, 155 LHP fuel pump. Ford Racing headers and a custom dyno tune.

If you don't have $2500-$3000 for new parts, you will never reach your goals.


You have an auto trans, so you will need 3.73 or 4.11 rear axle gears
 

Bobs88lsc

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Stroker is defiantly an option,if I had the dough to drop. I agree about the heads and ypur other suggestions. I,ll have to take it a piece at a time. Certainly upgrading the injectors and MAF and throttle body would be a start. Would twisted wedge heads be a workable option? Also,any ideas on what cam would be best? P.s. I appreciate your input. Thank you for taking the time.
 

jrichker

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Stroker is defiantly an option,if I had the dough to drop. I agree about the heads and ypur other suggestions. I,ll have to take it a piece at a time. Certainly upgrading the injectors and MAF and throttle body would be a start. Would twisted wedge heads be a workable option? Also,any ideas on what cam would be best? P.s. I appreciate your input. Thank you for taking the time.

The first thing you need to tell us is what your budget for this engine looks like. With that in mind we can advise you on what to shop for.

TW Trick Flow heads are a good choice. Be aware that you need special length pushrods, a push rod length checker tool, and stud mount rockers. That adds some $$$ to the cost of TW heads. That does not take into consideration the extra labor to get the pushrod length accurately calculated.

Fuel injector sizing & injector photos

Revised 26-Dec-2014 to add statement about figures are for flywheel HP and not rear wheel HP

Injector HP ratings: this flywheel HP, not rear wheel HP.
Divide flow rating by.5 and multiply the result by the number of injectors. This uses a 100% duty cycle. These ratings are for naturally aspirated engines at the flywheel.

Example:
19/.5 = 38, 38 x 8 = 304 HP
24/.5 = 48, 48 x 8 = 384 HP
30/.5 = 60, 60 x 8 = 480 HP
36/.5 = 72, 72 x 8 = 576 HP
42/.5 = 84, 84 x 8 = 672 HP

The preferred duty cycle is about 85% maximum, so for a safety factor multiply the final figure times .85.

19/.5 = 38, 38 x 8 = 304 HP x .85 = 258 HP
24/.5 = 48, 48 x 8 = 384 HP x .85 = 326 HP
30/.5 = 60, 60 x 8 = 480 HP x .85 = 408 HP
36/.5 = 72, 72 x 8 = 576 HP x .85 = 490 HP
42/.5 = 84, 84 x 8 = 672 HP x .85 = 571 HP

Remember that the above ratings are at 39 PSI. Increasing the pressure will effectively increase the flow rating. Example: a 19 lb injector will flow 24 lbs at 63 PSI, and a 24 lb injector will flow 30 lbs at 63 PSI.

See http://users.erols.com/srweiss/calcpchg.htm to get the calculators used in these examples.


Here's the duty cycle explanation. Duty cycle is how much of the time the intake is open the injectors are turned on. The 85% figure means that for 85% of the time the intake valve is open, the injectors are spraying. The idea is that you want some percentage of the duty cycle left over so that you have some room to grow the process.

If you are at 100% and you need more fuel, all you can do is turn up the fuel pressure. That means the whole fuel curve from idle to WOT is affected. Maybe you are already too rich at idle, and turning up the fuel pressure makes it worse. If you had some injector duty cycle left to play with, a custom tune could use that where it is needed. That would not over richen the whole range from idle to WOT.

If you did turn up the fuel pressure, you might be able to change the injector duty cycle to get the air/fuel mixture ratio you want since the injectors will have extra fuel delivery capability.

With larger than stock injectors or higher that stock fuel pressure, you will need an aftermarket MAF that matches the injector size. The MAF “lies” to the computer to get a fuel delivery schedule that meets the engine’s needs and isn’t too rich or too lean. The best strategy is an aftermarket MAF and a custom tune to insure the best air/fuel ratio over all the RPM range.

Don't forget to increase the fuel pump size when you increase injector size or significantly increase the fuel pressure



Diagram courtesy of Tmoss & Stang&2birds
Ford_Injector_Guide.jpg


See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host) for help on 88-95 wiring http://www.veryuseful.com/mustang/tech/engine/ Everyone should bookmark this site.

Ignition switch wiring
http://www.veryuseful.com/mustang/tech/engine/images/IgnitionSwitchWiring.gif

Fuel, alternator, A/C and ignition wiring
http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

Complete computer, actuator & sensor wiring diagram for 88-91 Mass Air Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/88-91_5.0_EEC_Wiring_Diagram.gif

Vacuum diagram 89-93 Mustangs
http://www.veryuseful.com/mustang/tech/engine/images/mustangFoxFordVacuumDiagram.jpg

HVAC vacuum diagram
http://www.veryuseful.com/mustang/tech/engine/images/Mustang_AC_heat_vacuum_controls.gif

TFI module differences & pinout
http://www.veryuseful.com/mustang/tech/engine/images/TFI_5.0_comparison.gif

Fuse box layout
http://www.veryuseful.com/mustang/tech/engine/images/MustangFuseBox.gif
 

Bobs88lsc

New Member
Jan 23, 2016
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Meridian Idaho
Sorry it too me so long to get back to you on this. Thank you for your wisdom. Currently looking to get gt40 upper and lower then have the head leveled. I agree that 400hp is overly agrees I've especially for a 308 block. I would gladly take 325hp at the flywheel till I can afford a 347(that is on the bucket list ),so I will apple the KISS principle moving forward. But,before I go all in on just the engine,I need to put in subframe connectors and swap out all the old rubber for the suspension and put in the turbocoupe front sway bar and 1"rear sway bar I have rebuilt koni red rear shocks that need to be installed, and am open to suggestions for the front suspension (including bolt on enhancements)to make sure the suspension as well as frame will support another 100hp over the stock 225hp engine. Like I said,I appreciate your comments,as I sometimes get a bit overzealous with my wishful thinking. Any other advice or comments would be much appreciated.