Cobra intake on GT

shovel

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An intake alone isnt going to do anything.

People keep saying this but it doesn't match my first hand results so who am I to believe - strangers on the internet or my own, lived experience?

I acknowledge that to you and everyone else I'm the stranger on the internet. I have posted to this thread a chart indicating that the stock HO manifold has a claimed ~20% difference in flow efficiency between the best and worst runners. I have posted a photograph of my own exhaust collectors whose soot-colors per-cylinder exactly match the expected outcome of rich and lean cylinders that coincide with which cylinders are expected to be rich and lean based on that flow difference. I have posted a video which demonstrates a dramatic change in exhaust tone after changing only the intake manifold.

The part for which I cannot provide evidence is my butt-o-meter so that much of it - to anyone else - is just some guy on the internet saying so. Shrugs all around.
 

badass98svt

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I'm not sure, 250ish probably. I don't want it to break, but I'd like a bit more than it has.

Ok, I was just curious so you could build the rear end accordingly. At 250 though, just throw some gears, and an install kit at it.
As far as the car goes, you shouldn't need to worry about breaking too much. The block is good til about 450 with a safe tune.
 

95opal

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People keep saying this but it doesn't match my first hand results so who am I to believe - strangers on the internet or my own, lived experience?

I acknowledge that to you and everyone else I'm the stranger on the internet. I have posted to this thread a chart indicating that the stock HO manifold has a claimed ~20% difference in flow efficiency between the best and worst runners. I have posted a photograph of my own exhaust collectors whose soot-colors per-cylinder exactly match the expected outcome of rich and lean cylinders that coincide with which cylinders are expected to be rich and lean based on that flow difference. I have posted a video which demonstrates a dramatic change in exhaust tone after changing only the intake manifold.

The part for which I cannot provide evidence is my butt-o-meter so that much of it - to anyone else - is just some guy on the internet saying so. Shrugs all around.

Buttometer isnt exactly verifiable evidence of anything. But thats just coming from a stranger whos been building these cars since the late eighties.
 

shovel

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Saying words on the internet isn't verifiable evidence of anything. Shall we get out the tape measure and unzip?

Anyway I have no stake in what OP does. Argue amongst yourselves.
 

joemomma

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Stock, you're looking at roughly 185 to the wheels through a 5-speed, assuming 15% loss. 250 to the wheels would be a 65HP increase at the wheels, which you would certainly feel/notice. Factor in the gears, and I think you'd be happy. I don't know how much 65HP would change numbers in the times to 60 or the 1/4, but I would think you'd notice it.

Personally, I'm shooting for 275-300 to the wheels with H/C/I, which should be achievable without too much fuss. With 4.10s, that should be a riot in a 3300# car.
 

ttocs

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I have never had anyone do anything to the car that they didn't finish the install by saying "I think I can tell the difference" from installing a K&N up. Your correct that it will/should move more air and that = more hp but the difference has never been measured I think possibly because it isn't worth the time to measure the difference. I mean realistically with all the differences in addition to the intake the cobra only had 30 more hp than the gt
 

tinnocker

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I had the upper and lower GT40 type intake ported by the ebay porter that barks like a dog. Added aluminum heads, shorty headers and larger throttle body, Comp cam. I dynoed around 280hp at the wheels. I was dissapointed. I thought I would get at least 300 hp. My tuner at Moe's in Dallas, Ga. wasn't impressed with the port job. Called the hp about normal for what I had. I thought the results of my super duper port job would impress him. I learned to not believe everything a porter tells you on ebay.
 

Maximum95

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I never considered porting the stock intake that would make things easier, especially with my desire to keep the STB on the convertible. I'll have to look into a place to do that.

I really appreciate the engagement here, my plans are already shifting based off of what people are saying.

I wonder how this plan would work: New gears, ported stock intake, rockers and springs, and retarded timing. Luckily I have under 90k on this engine, so not much is worn out from use, maybe from sitting. I know a few things have been replaced before I bought it, and it sat for years in a rich mans garage.

Like I said, I'm just looking to wake it up a little bit, I'm not trying to win any races, I just want a little more fun out of my weekend cruiser.

Thanks again everyone for the comments.

If you're interested in intake manifold porting, contact Tom Moss, or "TMOSS" as he's known on some other forums. I just got my GT40 lower ported by him. Came out fantastic. He has been porting manifolds for a long time, and may be able to offer some insight as far as porting the stock manifold goes. His email is [email protected]

Also, keep in mind that changing the rear end gear ratio will change your engine speed when driving on the highway. For example:

2,000rpm with 2.73 (stock) rear end: 82mph
2,000rpm with 3.73 rear end: 60mph
2,000rpm with 4.10 rear end: 54mph

Something to consider, while evaluating what exactly you want to do with the car.
 
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r1ch999999

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If you're interested in intake manifold porting, contact Tom Moss, or "TMOSS" as he's known on some other forums. I just got my GT40 lower ported by him. Came out fantastic. He has been porting manifolds for a long time, and may be able to offer some insight as far as porting the stock manifold goes. His email is [email protected]

Also, keep in mind that changing the rear end gear ratio will change your engine speed when driving on the highway. For example:

2,000rpm with 2.73 (stock) rear end: 82mph
2,000rpm with 3.73 rear end: 60mph
2,000rpm with 4.10 rear end: 54mph

Something to consider, while evaluating what exactly you want to do with the car.
I'm curious if you did a 6spd swap if those numbers would go down. Not that I want to spend that kind of cash.
 

badass98svt

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The 6th gear is just the overdrive. 1-5 is pretty much the same.
Like I said though, dont fear the gear. You can actually potentially pick up MPG around town, if you keep your foot out if it. Where you would normally be driving in 2nd gear, you will be in 3rd gear etc.
 

ttocs

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I have a t56 with 3.55s and 6th gear at 2 rpms is around 65 but that 6th gear is gonna cost ya....
 

Maximum95

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I'm curious if you did a 6spd swap if those numbers would go down. Not that I want to spend that kind of cash.

It would all depend on the overdrive ratio. The T5 in '94-'95 cars is .68 overdrive. I'm not sure what the available 6th gear ratios are in a T56.

My '95 spends most of it's drives on the interstate or state highways, so the 2.73 rear end works great for me.

It all depends on the end goal.
 

shovel

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You can figure out all your RPM's with https://percentcalculators.com/ - like if you have 3.08 now and you go to 3.73 you'll have ~21% more torque (at the wheels) for a given engine RPM and gear, but the engine will be turning 21% faster in that same gear at that same speed. 4.10 gears would mean ~33% . You'll also run out of rev's that much faster (either torque curve naptime or redline, whichever comes first) and need to shift that much earlier per gear.

This tool is also handy if you know your transmission ratios and tire diameter (stock is 25.7") https://spicerparts.com/calculators/transmission-ratio-rpm-calculator

You can preview how loud your engine/exhaust will be at cruise by dropping a gear and speeding up until your engine is at the new target RPM. Example if you cruise 75mph at 2000 rpm with 3.08 gears and you want to do 4.10 gears, your new RPM will be ~2700 at 75mph . So shift to 4th gear (assuming manual) and drive ~67mph which is about 2700 rpm and see how that feels.
 
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Snorky

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Yeah, take some time deciding what you use the car for most of the time. If you drive at highway speeds 90% of the time. The 4.10s will be a severe mistake. You will love it bombing around town. But by the 6th month driving on the highway you will say. This is stupid.or when you have to shift into 2nd before getting through an intersection. So just REALLY think about the reality of your cars use. I went full circle as my cars setups changed. Na. 3.73's.. rear blew up. Stuck 4.10s.. added a blower.. and then ET streets all the time. Car sucked on the highway and rain driving was always a white knuckle moment. Went turbo added far more power. Geared back to 3.55s... added more power yet and went to 3.27s.. so.. if its a drag only car. Figure out your current trap speed and then the trap speeds of people with the mods you want to do in the future. Gear accordingly to when you go through the traps.
 
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r1ch999999

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Thanks again, gears were my first planned mod, I thought I had 3.23 now, but I'm not sure. I was thinking 4.10s, mostly because it's a weekend cruiser, I don't drive in the rain and I don't go on the highway much with it. Maybe I'll reconsider and go with something a little less steep.
 

ttocs

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I had the 3.55s with the stock tranny for a while and 5th gear at 65 left me I think around 3k rpms.
 

duh09

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Thanks again, gears were my first planned mod, I thought I had 3.23 now, but I'm not sure. I was thinking 4.10s, mostly because it's a weekend cruiser, I don't drive in the rain and I don't go on the highway much with it. Maybe I'll reconsider and go with something a little less steep.

4.10's really aren't as scary on the highway as the world would have you believe. If boost is in your future, 4.10 don't let the car build enough steam - but for a N/A car they're not a big deal. 3.27s to 3.55s seem to be the sweet spot for a turbo car, bumping up a little for S/C cars.

Everyone's got a different opinion on the matter, but I daily drove my 95 GT with 4.10s, gutted, with fixed buckets for a couple years, including back and forth to college which was a 4 hour one way drive every weekend almost. I've owned that car with 4.10s, one with 3.73s, and another with factory 2.73s - there's a decent seat of the pants difference between 4.10s and 3.73s, but there's only around a 2-300ish RPM difference at 70mph. If I remember correctly, 70mph was around 2500ish RPMS cruising. I must more preferred the lowered gears cars in ALL situations when compared to factory gearing. Around town, interstate - all considerably improved versus stock.

Bang for your buck, gears will be the absolute biggest change in how your car drives compared to any other performance mod. Don't fear the gear.
 
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r1ch999999

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4.10's really aren't as scary on the highway as the world would have you believe. If boost is in your future, 4.10 don't let the car build enough steam - but for a N/A car they're not a big deal. 3.27s to 3.55s seem to be the sweet spot for a turbo car, bumping up a little for S/C cars.

Everyone's got a different opinion on the matter, but I daily drove my 95 GT with 4.10s, gutted, with fixed buckets for a couple years, including back and forth to college which was a 4 hour one way drive every weekend almost. I've owned that car with 4.10s, one with 3.73s, and another with factory 2.73s - there's a decent seat of the pants difference between 4.10s and 3.73s, but there's only around a 2-300ish RPM difference at 70mph. If I remember correctly, 70mph was around 2500ish RPMS cruising. I must more preferred the lowered gears cars in ALL situations when compared to factory gearing. Around town, interstate - all considerably improved versus stock.

Bang for your buck, gears will be the absolute biggest change in how your car drives compared to any other performance mod. Don't fear the gear.
I had an 03 Ranger, 4.0, 4.10 rear end with a manual. That truck was awesome. Wife got pregnant and I traded it for an 03 Sport Trac, 4.0, 3.27 with a manual. That thing disappointed me on a regular basis.
I have a 4.3 rear end in my Tundra, I leaning toward the 4.10s.
 

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