Need some opinions

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I have a 97 gt with the 4.6l and I was curious as to how to go about trying to get more power. I've been told to PI swap, engine swap, and even putting boost. I have it tuned on after market ECU with minor upgrades and on the dyno I was putting out 273 hp. I just dont know too much about the engine and wanted an opinion from someone who was more familiar with building one. I've been told to add any boost, either turbo setup or supercharger, you have to PI swap no matter what. Is this true and is there any advice I can get?
 
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08GT500

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I have a 97 gt with the 4.6l and I was curious as to how to go about trying to get more power. I've been told to PI swap, engine swap, and even putting boost. I have it tuned on after market ECU with minor upgrades and on the dyno I was putting out 273 hp. I just dont know too much about the engine and wanted an opinion from someone who was more familiar with building one. I've been told to add any boost, either turbo setup or supercharger, you have to PI swap no matter what. Is this true and is there any advice I can get?
Hi,
Planting 273 with bolt-on’s sounds as if the Intake May be a PI version, appearance is identical externally, and the main reason behind the gains with a PI upgrade. PI Intakes don’t fit NPI Heads perfectly but they used to sell adapter plates that allowed proper fitment.
Many also got too creative with Permatex to make them fit.
1) What are your goals for HP/TQ.?
2) How many miles on your 4.6?
3) Are you seeking FI versus NA?
Best!
-John
 

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I don't want anything crazy for hp, as my car has 170k miles. I bought it for a project so rebuilding the motor or getting a crate motor is when I would want to try to get the most out of it. Currently my goal was ballpark 300/325hp, if possible on mostly stock internals and high mileage as i dont have a few thousand dollars to rebuild the motor. I have a built rear end with racing clutches, limited slip differential, and aluminum driveshaft so tq isn't my main concern until I can eventually make the power to work up to that. I would like to go FI but I dont think a high mileage car would last very long under the pressure. I dont know much about the SN95 platform other than what the motor is, I dont know what to do in the aftermarket area to see an increase in performance.
 

08GT500

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Hi,
Well, the PI swap would get you to a solid 260HP, from 215hp stock. We’re talking grossHP, not RWHP. If you’re planting 273RWHP, that means your motor is making about 15% more. (15% represents the power loss through the drivetrain.).
Ironically, your motor would be now be making 314 Crank HP to be planting 273RWHP. You’re seeking 300-325RWHP?
It’s a feat to get beyond 300HP without the PI swap, or going with aftermarket head’s, or potted & polished Heads, Cams, NOS.
The PI Intake manifold is 90% of what actually improves the HP/TQ, and they are often installed without PI heads or Cams, many times without the adapters you can no longer find, with Silicone to seal it all up (yes, bad!) as I’d posted earlier.
A list of what you already haveI would be super important, (at least what you know of, internally- if anything) and/or to post a picture or pictures of your engine bay , would also help gain some insight.
We don’t want to re-invent the Wheel-right?
A great mod, about the best for the price is by running lower gears, but sounds like you may have them. Can you confirm this by picking up the rear & counting driveshaft/tire revolutions to know what it has for gears now. Stock should be 3.08’s.
There’s a point on the 4.6l 2V motor’s where you hit a HP ceiling and need to make a decision on which way to go, FI, or NA.
There’s still many ways to go about it, but again, we know to know what’s already there.
No. It’s certainly not as cheap as an 86’-93 Foxbody 5.0 to build, which is why many SN95 owners go FI if they want big gains with the 4.6l 2V Motor’s, or go DOHC on the SOHC motors, or transplant a Coyote in and go nuts, etc.
Any info will help. How does the car go now, if it’s running right, I’d think it’d be pretty strong. I’d had a 96’ and hit it with countless 150HP NOS shots with over 200k on it. It never let me down. That’s no guarantee.
These motors are resilient, properly maintained. For instance, filled with good reciprocating assamblies, externals, a Tekskid block can support over 1,000HP.
You’re right, a motor with that mileage may not handle much more for a long period of time, if you did FI now (Centrifugal Supercharger) you could plant it on the next motor you drop in. It’ll be cheaper to buy parts now that a year from now. No doubt.
Buy one from a boneyard & just have a shop Hone it & check it out. Slowly build it in parallel while running this. When it’s time, swap the FI parts over to the fresh motor setup for higher boost levels. Doing the assembly yourself is cheaper, and very rewarding.
I’ve seen them FI’d into the 250K range, but it comes down to how it was maintained.
Have an article you may want to see. I’d done this to a guys 97’ GT years ago.
https://www.hotrod.com/articles/hrdp-1105-592hp-46l-2v-motor-for-2298/
This also hinges on how strict the DMV inspections are in your area. If they are not strict there, building becomes much cheaper and I’d be more than happy to give you suggestions to turn into a monster.
Best!
-John
 
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The hardest thing about the car being a project, it's had many owners. From talking to the guy I bought it from, and one other previous owner, its had at least 5 owners, and 1 of them took it to the strip quite a lot. As of knowledge I have of the car after talking with them is: the Ford racing clutch, built dif, cold air intake, and a tune from an unknown tuner or brand, and also the dyno results weren't correct, i made 224whp, about 250 bhp. The tune makes the engine run extremely lean too. And i did do some research and it doesn't have any PI parts on it that i have knowledge of. Ive been having problems with the motor since I've had it, for example, oil disappearing not from the exhaust or any gasket leaks, piston slap or valve float haven't been able to connect the dots yet,, lean codes, clutch engagement, doesn't like to start and stay running when not warm, extremely hard grinds at high RPM upshifting as well as reverse, slight intermittent electrical power loss under medium and high acceleration. I have more knowledge of whats wrong more than I actually know what has been done to it so its a matter of fixing whatever they did to it then doing what I want to it. Where I live there aren't any performance or even shops I can take it to where they can take it apart and tell me whats wrong with it they are all collision repair and regular maintenance and won't touch anything other than stock parts. There isn't even a place that will repaint my car except for collision repair. Im not a mechanic by any means but i think maybe a new platform might be my best option, in terms of just buying a crate motor rather than spending about the same amount of money and time rebuilding a motor that was probably beaten to hell and back.
 

08GT500

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Hi,
I’m going to be straight with you, please don’t confuse it with me talking down to you nor being rude-k? That’s not what I’m about. You’ve brought up several valid points and I’ll do my best to answer them.
Trifecta common to preservation of any Vehicle’s endurance- longevity- reliability, is by applying firm maintenance strategies specific to the vehicle and it’s usage, being vigilant in quickly addressing any warning signs, and not pushing a vehicle nor its engine/powertrain combo- stock or modified, beyond the established design limits of its intended capabilities.

The optimal build has a strong balance between its drivetrain, chassis, suspension, braking, and safety systems.

Do you have a Shop Manual for your GT? Pick up a Chiltons or Haynes shop manual. Excellent information there.
Do you have a decent set of hand tools, and is there an Auto Parts store local to you that rents/loans specialty tools?
Is there an automotive specific machine shop (engine rebuilds) local to you that has a good reputation?
If there’s a chance that your car is running lean, the last thing you want to do is be hard on it now.
The problem with buying a crate motor and not going to a local automotive specific machine shop is that if a failure occurs, they won’t likely be very reasonable as one with folks you dealt with face to face. The
1) The Cars an OBD-2, the most user friendly diagnostic platform. Do you have a good Scantool; one that allows you to watch streaming sensor data, record & later view engine data via drive cycles, etc?
This is something you should really have. They’re not expensive, more of a necessity.
2) As described, you’ve mentioned the motors running lean. Best to halt any hard driving until it’s corrected.
3) Clutch not disengaging fully sounds like it’s may be your issue with your Transmission grinding on high RPM up shifts.
4) Oil loss, how much are you losing over timeline, 1/2 Qt per 100 miles, etc?
5) Many of the things described sound like poor grounds and power connections, potentially vacuum leaks and a sensor or two.
6) First think is suggest doing is to run a compression test, and a leak down test. See what the condition of the motors really like within the Cylinders.
7) Your oil pressure needs to be checked (with a mechanical gauge I’d suggest). You can buy a mechanical gauge for 20$ with a bracket, or rent a mechanical test kit for about the same. You’ll want a Mechanical gauge on whatever you end up doing anyway, so it’s not wasteful.
8) Can you post a picture of the engine bay?
9) Post the DTC Codes.
10) Has the EEC reflashed, or is there a chip sticking out of the back of it (J3 Port)? If there’s a Chipset, snap a pic & post it.
11) What exhaust system is the car running, are their Cats, long tube or shorty headers- or stock manifolds?

Remote Tuning that works just fine...


Best!
John
 

Nightfire

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The first thing you need to do is ditch the motor. Source another 4.6 2V (remember even crown vics/F150's/etc came with the same basic motor).

Secondly, ditch the tranny and replace it another used one.

Concentrate on just those two tasks and you will alleviate most of the problems. Check EBAY and even junkyards. Sometimes you can strike gold at a junkyard. Take things one step at a time. We'll worry about the rest once you complete those tasks.
 

08GT500

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Jul 12, 2018
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The first thing you need to do is ditch the motor. Source another 4.6 2V (remember even crown vics/F150's/etc came with the same basic motor).

Secondly, ditch the tranny and replace it another used one.

Concentrate on just those two tasks and you will alleviate most of the problems. Check EBAY and even junkyards. Sometimes you can strike gold at a junkyard. Take things one step at a time. We'll worry about the rest once you complete those tasks.
Nightfire, like the simplicity of your post.
There’s no doubt, this motor sounds like it’s been whipped beyond the brink.
Among the other vehicles listed that have the 4.6’s, the Crown Vic’s made the (CVPI) Police Interceptor 2V 4.6 from 92’ until 2011, and although they’re driven hard, they’re also maintained (especially state police Cars).
There is some treasure to be found in the boneyards, and it’s certainly worth considering the extra bit of footwork on your end.
Keep in mind as the years change, the harnesses and EEC’s did as well.

Gold to locate a running donor vehicle & have them drag the extras back to the boneyard once you’re done with it.

They are significantly more abundant in availability these days as most Police departments are phasing them out for the SUV’s.
For what you’re seeking it’s not unreasonable, nor a 10K$ project.
You have some boneyards pretty local to you, finding a healthy 4.6l 2V right out of another (preferably crashed) vehicle that has a lot more life left, after that- It’s nuts, bolts, and pretty much plug & play with the right year, donor vehicle.
The top ends & timing sets are most vulnerable on these cars, but with the track mileage and oil loss, noises, etc, it’s quite likely beyond that, as you mentioned, it’s already becoming a project on top of another project.
Myself, I’d still run a few tests just to know exactly where it’s at. For me, a T-45 Trans is a simple rebuild, 350$ stuffed with some stout parts.
Hope the info will allow you to make the decision that best suits you..
Best!
John

some good reads..


 

Nightfire

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To be completely honest, it sounds as if multiple people were just trying to unload this car because of the multitude of problems. Its a shame. I would have had multiple trusted mechanics look over the car prior to purchase.
 

08GT500

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Yeah, pretty irritating that these folks can’t get off their arse, be responsible, take some initiative, ask questions, do a little research & spend a few bucks, bloody a few knuckles wrenchin’, feel pride in their accomplishment. That’s a Great feeling.
Instead, they pull out all the stops & beat something to death, lie through their teeth about it, money’s in their pocket & someone else with good intent pays the price, can’t believe this happens, people’s “word” used to mean something. “Trust?”
Think we need to re-incorporate Hazing on these liars in instances such as this, lol. :chair:
 
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