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91 5.0 EFI Eddie Bauer
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Discussion Starter · #1 ·
Back in the day if you want to increase HP you just put on Headers a big 4 barrel carb.
What do you do now days with EFI?
I just pick up a 91 FSB with a stock 5.0 EFI. I'm looking to gain as much HP as I can without opening up the engine.
What do you recommend?
 

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Ford Hoarder
78 & 92
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91 will ultimately be limited by its Speed Density Based system and what you will be able to do, to really build power.
Making what you have run the best it can will be your best bet. Look into doing a full tune-up, and the Six Liter timing bump and plug gapping.

I like to run an ignition box, as they typically increase throttle response. A perfromance valve body and set of gears will also change the drive-ability of the truck as well.
 
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Yo Fixit,
Welcome!
I'll move this thread to Noobie section for better visibility. No charge!😎

See EFI Performance Upgrades by member and Ford Bronco, etc EFI GURU Fireguy50 (Ryan M) @ Ford Fuel Injection » EFI Performance Upgrades

And Ryan's How to Pick a Camshaft for EFI (BRONCOS)" @ How to pick a CAMSHAFT for EFI

Also consider:
MAF Swap in an 89 F 150 by Booba5185 @ MAF swap sensor
He wrote, "
I found the following cars used this MAF, while also using 19 pound injectors:

1995-94 Mustang 3.8L F2VF-12B579-A2A,
1994-92 Crown Victoria 4.6L F2VF-12B579-A2A,
1995-94 Mustang, Mustang Cobra 5.0L F2VF-12B579-A2A,
1994-92 Town Car 4.6L F2VF-12B579-A2A,
1994-92 Grand Marquis 4.6L F2VF-12B579-A2A

Mustang guys upgrade to these MAF housings because they are 70mm (stock Mustangs are 55mm), just like the truck's MAF housing. The specific MAF I ended up with was off of a 1994 Grand Marquis 4.6L, and it bolted directly onto the truck's airbox. Honestly, I think I could have dropped the new MAF into the truck's housing and called it good, but I just wanted to be sure. I wanted to update the thread for anyone who has these questions in the future."

MAF Upgrade in a 90 by Seattle FSB @ MAF Upgrade - Lessons Learned Thread

COLD air intake - insulate air intake from grille entry area to throttle body.
Air Tube & Box Insulation pics in a 94 5.0; Ken used Reflectix Insulation, avail @ Lowes. etc. ST16025 - 16" x 25 feet. miesk5 Note; Ken installed the K&N® & removed the cold air intake tube that runs to the top of the radiator; but he could have installed the intake tube section later.
One pic for example;

Source: by Ken B (Kenny's 94) @ 1994 Ford Bronco insulating air box and intake tube pictures, videos, and sounds | SuperMotors.net

Some use a 4.9 EFI engine's air intake inlet

Try Sixlitre Tune-Up @ ignition upgrade and timing bump (no 56K)

See Project M.P.G. in a Centurion 460; miesk5 Note, Results are Comparable to Tests in other Ford Engines
Source: by performanceunlimited.com
Some use this information while others write that some results are not achievable.
⊙●⊙
Here is the 1990 F Series/Bronco Pre-Delivery Shop & Electrical & Vacuum Troubleshooting Manual (EVTM), Partial by member Kingfish999 in Google Drive (similar to your 91) @ 1990 Ford Truck service manuals - Google Drive
Slow scrolling for my slow Comcast Highest Cost Blast Internet..
Suggest you download the docs for faster scrolling and to use the page index.

1991 Bronco Dealer Brochure by Ford via via Dezo's Garage @

Haynes Red Manual for 80-95 Bronco & F Series @ Hanes guide 80-96 bko f series.pdf via member BroncMom

For any questions, it's better to post each seperately in Noobie section. This will get more attention and you can build up your post count to get into other sections such as Bronco and Ford Parts/Accessories that requires 50 non-padded posts to participate due to scammers who preyed on our members.

Our Forum FAQs includes for example, How To Upload Images To Posts, How to Use Search and more tips!

Baba Looey's Favorite FSB Links (lots and lots of tech links)including, "how do I get the tailgate glass to...", etc

Try to find time to participate and vote in our Full-Size of the Month Contest & later in the year, Full-Size of the Year Contest @ Voting
You will get ideas by those competing.
Prizes are awarded to Winner; a full spread in Bronco Driver Magazine is the top prize, in addition to a years subscription, once the article is submitted and a years worth of premium FSB membership!

Al
 

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Check out my other post here. You don't have to be limited by speed density anymore.
https://www.stinger-performance.com/ makes a megasquirt 3 tuneable ECU that plugs into your factory 60-pin ECU connector. (I promise I don't work for them. I'm just impressed with their product.)

Having said that, changing to their ECU by itself won't add power, but it will allow you to add mods to your engine without being limited by the factory Speed Density ECU.

 

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Premium Member
93 XLT 347, GT40 Heads, Bassani headers/exhaust, E4OD
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91 will ultimately be limited by its Speed Density Based system and what you will be able to do, to really build power.
Making what you have run the best it can will be your best bet. Look into doing a full tune-up, and the Six Liter timing bump and plug gapping.

I like to run an ignition box, as they typically increase throttle response. A perfromance valve body and set of gears will also change the drive-ability of the truck as well.
Speed Density doesn't get much love... One needs to be mindful of cam limitations, however it's not the end of the world. There is a fair amount that can be done in a balanced system designed to work within a speed density's operating envelope (see my sig.).

You have a solid throttle body and arguably one of the best Windsor intakes Ford ever designed. The real limitation is in the stock heads, but you mentioned you didn't want to crack open the engine. Headers and a 3" exhaust with high flow cats will help, certainly will sound better, but isn't going to make much difference in the seat of your pants or stop light to stop light.

@CrazyBRONCOguy hit it though. First get it running right (cap, rotor, wires, plugs and a timing bump), then look at tightening the transmission up (valve body/shift kit) and then gearing - what my first boss referred to a as "butt-dyno enhancers".

One additional thought, if you might even think of dropping a 351 (or 460!) in place of the 302, don't waste the money on a high end exhaust until after you have made the engine swap.
 

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91 5.0 EFI Eddie Bauer
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Discussion Starter · #6 ·
Thanks Guys,
The truck is in good shape with just a little rust, but the interior needs a lot of work. My plan was to spend my first real money ($2k) on getting what I can out of what I have, (Tune-up, K&N intake, Headers, Exhaust), then work on the interior. From reading this and other threads, that putting in a 351W is the way to go. I normally just fix what breaks, I'm new to this "building up" things. Keep the advice coming.
 

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93 XLT 347, GT40 Heads, Bassani headers/exhaust, E4OD
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Thanks Guys,
The truck is in good shape with just a little rust, but the interior needs a lot of work. My plan was to spend my first real money ($2k) on getting what I can out of what I have, (Tune-up, K&N intake, Headers, Exhaust), then work on the interior. From reading this and other threads, that putting in a 351W is the way to go. I normally just fix what breaks, I'm new to this "building up" things. Keep the advice coming.
Don't waste your money on the k&n intake and don't assume the 5.8l is the be-all/end-all... the 5.0l you have under the hood may be the "jack-of-all-trades, master-of-none", but it's still quite capable.
 

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91 5.0 EFI Eddie Bauer
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Discussion Starter · #8 ·
Don't waste your money on the k&n intake and don't assume the 5.8l is the be-all/end-all... the 5.0l you have under the hood may be the "jack-of-all-trades, master-of-none", but it's still quite capable.
Being old school as I am, I was going to go with tuned shorty's and no cat duel exhaust. I've seen a lot go 2 to 1 with the 3" exhaust. Your thoughts and why?
 

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93 XLT 347, GT40 Heads, Bassani headers/exhaust, E4OD
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Being old school as I am, I was going to go with tuned shorty's and no cat duel exhaust. I've seen a lot go 2 to 1 with the 3" exhaust. Your thoughts and why?
Tuned shorty's - good, have been very pleased with the Bassani's on my truck, but the gain is likely marginal given they are shorty's - they look cool though. EDIT: marginal relates to equal length or "tuning" vs generic headers. Headers are an improvement over stock manifolds. Sorry if that wasn't clear.

Dual's - doable, however your transfer case is in the way on the driver's side. By the time you swing it over, run it along the frame on the passenger side and swing it back over to the driver's side, you lose the advantage of going to duals in the first place. Add that connecting the left and right engine banks improves scavenging, why bother? Just run a single 3". Also, don't run the exhaust straight out the back, it will get drawn into the cabin when you have the rear window down.

Cat delete - why? Not only is it bad for the environment, but your engine needs some back pressure to improve torque and driveability. Modern cats are not only more efficient air scrubbers they do so with little detrimental restriction. Again, look to Bassani's single high flow catalytic converter. Drop it in and then delete the smog pump. Modern cats don't need it and you eliminate the parasitic drag of the pump. A win-win: you get a performance bump while actually reducing emissions. Leave the EGR in place, cap the vacuum lines to the TAB and TAD controllers, but remove all of the other smog related plumbing from the rear of the engine, plugging the holes in the back of the heads. A quick search for smog delete here on the forums will provide more details.

I get old school. Heck, I put the "O" in old, but these EFI engines are a different beast from the past when flipping a breather cover and dropping true duals with a couple of Thrush mufflers actually made a difference.
 

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91 5.0 EFI Eddie Bauer
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Discussion Starter · #10 ·
Tuned shorty's - good, have been very pleased with the Bassani's on my truck, but the gain is likely marginal given they are shorty's - they look cool though. EDIT: marginal relates to equal length or "tuning" vs generic headers. Headers are an improvement over stock manifolds. Sorry if that wasn't clear.

Dual's - doable, however your transfer case is in the way on the driver's side. By the time you swing it over, run it along the frame on the passenger side and swing it back over to the driver's side, you lose the advantage of going to duals in the first place. Add that connecting the left and right engine banks improves scavenging, why bother? Just run a single 3". Also, don't run the exhaust straight out the back, it will get drawn into the cabin when you have the rear window down.

Cat delete - why? Not only is it bad for the environment, but your engine needs some back pressure to improve torque and driveability. Modern cats are not only more efficient air scrubbers they do so with little detrimental restriction. Again, look to Bassani's single high flow catalytic converter. Drop it in and then delete the smog pump. Modern cats don't need it and you eliminate the parasitic drag of the pump. A win-win: you get a performance bump while actually reducing emissions. Leave the EGR in place, cap the vacuum lines to the TAB and TAD controllers, but remove all of the other smog related plumbing from the rear of the engine, plugging the holes in the back of the heads. A quick search for smog delete here on the forums will provide more details.

I get old school. Heck, I put the "O" in old, but these EFI engines are a different beast from the past when flipping a breather cover and dropping true duals with a couple of Thrush mufflers actually made a difference.
Got it. Thanks for the advice. I will look into the Bassani headers and a high flow cat with a 3" exhaust. Planed to go out the side anyway.
One more question. You have 31/10.5-15's. Is there room to go a little bigger without a lift kit?
Thanks in advance.
 

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93 XLT 347, GT40 Heads, Bassani headers/exhaust, E4OD
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Got it. Thanks for the advice. I will look into the Bassani headers and a high flow cat with a 3" exhaust. Planed to go out the side anyway.
One more question. You have 31/10.5-15's. Is there room to go a little bigger without a lift kit?
Thanks in advance.
That's well answered in the first stickie to the Noobie section. I'd link it but am on my phone. Shouldn't be hard to find though!
 
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