GT40 upper and lower for an 86

[ITdude87]

Questions.

Debating on finding a GT40 tubular upper and lower intake manifold for the 86' this winter.

Is this plug and play friendly with speed density?

Are the factory injectors and throttle body OK with this combo?

Are there any "gotchas" to consider?

What should I look out for? I see there could possibly be some minor variations on the lowers?

Any information before I even start looking would be great. If this is a plug and play swap I think I'll go for it. Extra power is nice, but I'm doing it primarily for the cool factor and looks - Would prefer not to swap computers or go MAF.

[Aarav]

Questions.

Debating on finding a GT40 tubular upper and lower intake manifold for the 86' this winter.

Is this plug and play friendly with speed density?

Are the factory injectors and throttle body OK with this combo?

Are there any "gotchas" to consider?

What should I look out for? I see there could possibly be some minor variations on the lowers?

Any information before I even start looking would be great. If this is a plug and play swap I think I'll go for it. Extra power is nice, but I'm doing it primarily for the cool factor and looks - Would prefer not to swap computers or go MAF.

Considering a GT40 tubular upper and lower intake manifold for the '86 raises questions on compatibility with speed density, injector and throttle body suitability, any complications, and potential variations. Seeking pre-research guidance for a plug-and-play swap is the aim, focusing on aesthetics without altering computers or using MAF.

[ITdude87]

Thanks Robocop?

[ZEN50]

Ahhh what?

[mcb82gt]

Ahhh what?

Im missing something and confused as well. lol

[85GTGuy]

I'm not sure myself, but Aarav is a brand new member. And his 2 posts seem like something ChatGPT (or some kinda other AI computer), would write. Dunno though.

Is that what you were getting at ITdude87?

[ITdude87]

I'm not sure myself, but Aarav is a brand new member. And his 2 posts seem like something ChatGPT (or some kinda other AI computer), would write. Dunno though.

Is that what you were getting at ITdude87?

Yep. I can smell a bot a mile away.

"Thanks Robocop" was sarcasm



Soooo....About those sweet tubulars??

[Autobahn]

Is this plug and play friendly with speed density?

Not really....

The "GT40 family" flow better in high RPM but less velocity at low RPM. A speed density ECU is not calibrated for, so load is not correct.

[ITdude87]

Yeah. Facts.

I did some more digging around and it sounds like a MAF/Computer/TB (86's are smaller than others)/Injector swap would make it the happiest - Not really a plug and play deal.

Maybe some other day.

[MIKE'SVO86]

Yep, 86 was the most choked out year for the 5.0. You'd need to do everything you have listed, plus heads (E7s or GT40Ps) to utilize that intake.

[Autobahn]

I like the tubular, a good manifold for street use. I'm just building this motor for my capri.

[ZEN50]

Slap a 65mm TB on it and call it good, no need to swap to MAF or all that other stuff. Sure, it won't make huge HP gains but it will look cool

[ITdude87]

Call me crazy but that’s sorta what I’m going for Zen. Something really mild and more for looks. How about the EGR piece, would that match up to a 65mm? If I can do that and not worry about the car running poorly, think I’d go for it and start my treasure hunt.

I’m going to pull the upper and lower to get some new gaskets in anyways, and I’d like to use that as my chance to swap.

[OX1]

Had to bore mine out..............

[MIKE'SVO86]

Now that's the way to do it. Offering a machining service?

[OX1]

Now that's the way to do it. Offering a machining service?

All my stuff is a labor of love. We (woman and I) have 11 vehicles, 2 trailers, boat (and trailer), bobcat.
Don't have much time for stuff like that, and it's rarely fun doing stuff the second time, LOL!!
I will retire in 2-3 years though, then maybe.

[MIKE'SVO86]

Understand. Figured I'd ask.

[ZEN50]

You can buy larger spacers, 65mm. Heck I probably have a used 65mm spacer & TB here laying on the shelf.

[mcb82gt]

Call me crazy but that’s sorta what I’m going for Zen. Something really mild and more for looks. How about the EGR piece, would that match up to a 65mm? If I can do that and not worry about the car running poorly, think I’d go for it and start my treasure hunt.

I’m going to pull the upper and lower to get some new gaskets in anyways, and I’d like to use that as my chance to swap.

Do it! It'll run fine. A cam change is what can really throw off the SD. The E6 heads are the big bottleneck, the tubular wont reach its full ability, but will run fine.

[ITdude87]

the tubular wont reach its full ability, but will run fine.

Roger that. This would be more for cosmetics than power, appreciate the input.

It sounds like the 87 cars used 19lb injectors and 65mm TB's as opposed to 19lb/55mm in 86. - So fuel injectors would be good to go.

What worries me is the computer not knowing it's got ~15% more airflow from the larger TB, and to be honest, I just don't know a ton about how speed density works other than it reads manifold pressure and adjusts fuel from there. I think it's safe to assume the 87's have a different computer to compensate? OR...Would the 86 computer be smart enough to see the increase in pressure from the +15% and adjust? In theory it would be similar to the difference between a cold sea level and a hot mountain car back in the day - yeah? Overthinking this?

Heck I probably have a used 65mm spacer & TB here laying on the shelf.

Take a look and let me know!

[MIKE'SVO86]

You can buy larger spacers, 65mm. Heck I probably have a used 65mm spacer & TB here laying on the shelf.

Yep, hard to find the 67MM Ford Motorsport spacer, so this would be a good alternative, keeping it Ford parts.

[Autobahn]

A speed density ECU works with theoretical values. It commands fuel by comparing:

RPM vs. TPS vs. MAP

Correct air flow to/with ECU? Use a MAF-Sensor.

[mcb82gt]

Roger that. This would be more for cosmetics than power, appreciate the input.

It sounds like the 87 cars used 19lb injectors and 65mm TB's as opposed to 19lb/55mm in 86. - So fuel injectors would be good to go.

What worries me is the computer not knowing it's got ~15% more airflow from the larger TB, and to be honest, I just don't know a ton about how speed density works other than it reads manifold pressure and adjusts fuel from there. I think it's safe to assume the 87's have a different computer to compensate? OR...Would the 86 computer be smart enough to see the increase in pressure from the +15% and adjust? In theory it would be similar to the difference between a cold sea level and a hot mountain car back in the day - yeah? Overthinking this?



Take a look and let me know!

I run the larger HO throttle body on my 88 cougar stock ecm and 14lb injectors. Youll be fine. The SD setup can compensate a bit and adjust for the increased airflow.

the 87 up cars had 60mm TB

[OX1]

86 was 58mm throttle body (87/88+ mass air meter was 55mm).

[85GTGuy]

@ITdude87 - Not sure if this link will work for ya....

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