i have a 97 epxy and truck runs good but the thing is completly out of steam by 4200 rpm at the highest (5.4l) i recent took a buddies 2000 f-150 on a road trip and there is a definate difference on how the trucks behave. mine shifts at 4600 rpm under full throttle and his is around 5100, his pulls from off idle till it shifts and generally feels much stronger above 3500 rpm. reason i ask is i wanna put some aggressive tires on and in the mud some upper rpm HP is def gonna help a ton. i know the mustang went from 225 hp to 260 on its 4.6 from 98-99 model year with no loss and even gained some tq. weird thing is our trucks are rated at the same hp and tq??? off idle mine has much more torque. how did the PI heads affect real world expireince. i dont mind actually dyno tuning the truck and i might tune it on premium gas (only drive it 5-7k a year not a big issue) truck is getting a full exhaust from headers back and alreay has a k&n cold air. new to modular world this year so forgive me for sounding like a noob.

 

did my own homework found out they are not rated the same mine is 235/335 and the pi install makes premium fuel necessarry (which im ok with) i guess now im just curios to see who has done it and how you liked the results

 

Why are you so afraid of the additional 5-6 bucks per fill up???



You want to make more power and get better mileage, but yet you want to run crap fuel?


When is the last time you performed any preventative maintenance? I’d be willing that has a lot to do with the truck running out of “steam” as you called it.



you can always swap in a lower mileage PI motor, but honestly I think you'd be better off with the PI heads, PI intake and a custom tune

 

or you could always add a supercharger

 

Well I said I don't mind running premium fuel and dyno tuning it for that octane im not some noob to cars I have a fox that runs mid 9s and is a street car and a 04 mach 1 with aftermarket cams exhaust and a little n2o that runs 11.30s and is my daily driver with a/c and nice stereo. both worked on and built everything myself. Yes maintenance has been done on the truck I bought it 2 months ago and replaced most of the front end put a k&n drop in and some ngk tr6 plugs. So to my question im looking for someone who has done this and can provide real world driving dynamics differences. Its a lot of work to pull out a perfectly good running motor for mediocre results. I know what it looks like on paper but I want to know real world results. Forced induction is not completely out of the question but why not start with more power in the first place.

 

http://www.f150online.com/forums/v8-...-v10-swap.html

how much hp gain on full pi conversion an my 1998 Mustang GT - Ford Mustang Forums


Parts needed for PI intake swap (PICS INSIDE) - Modular Depot Forums

 

I know of a couple of people that have engines with the PI heads including myself and in the manual it doesnt say to run premium fuel.

 

The pistons are completely different the NPI heads have a much larger combustion chamber when puttin PI heads on a NPI shortblock it brings compression up to around 11:1 which would require premium fuel. So far I have not had a legit answer to this question is there anyone who actually knows what they are talking about. Im used to much more technical answers from some of the mustang forums so if there is someone on here with actual expirience other than bolt on exhaust and athstetics on these trucks plead refer me to them so I can PM them a few questions.

 

LOL, I dont know how much easier I could say what I did but I'll try it again but a little different so you can understand what I am saying. A few people that I know that have PI head including myself does not run premium fuel nor does it even say to run it in another friends of ine which even came from the factory with pi heads.

 

I also did not know that I said they were the same, damn

 

What he is saying ,doing a PI swap on a NON PI block will raise the compression ratio. There for you need to run premium fuel.
No , it's not in any manual like that...lol

Did you do a PI swap on your truck?


(To the OP)
Not worth the trouble!
I would swap in a newer PI 5.4 and put an Lightning intake assembly on it.
If you do a PI swap, you'll have the compression so high,,, you wont have a good setup to supercharge.

 

On my Expedition, I bought it already done, not sure if from the factory or what but on a Mustang of mine I did the change and I use Regular fuel.

 

Yeah I understand the raised comp is not ideal for a blower but I didn't wanna go that route yet anyway. If I do have that kinda budget in the future ill put a set of TFS heads on it with the big chambers. And I agree with just swapping a PI motor in there that might be the easiest most cost effective solution. Ill be on the lookout for one with lower miles than mine (138k). My goal is to get over 300 fwhp and have a bit more top end pull (to 5500 or so) but not lose low end. That was my biggest reason favoring just a head swap. The comp increase makes for a very responsive motor with tons of off idle tq. Thanks finally for some legit info and ill start a thread on here when I start the swap and ill provide some before and after driving impressions and what it looks like on paper

 

[quote=phil6608;9797017] What he is saying ,doing a PI swap on a NON PI block will raise the compression ratio. There for you need to run premium fuel.

Just for doing a head change from the npi to the pi heads is not going to increase your comp so much that you wont be able to use regular fuel. I guess some people like to waste money thinking they need to run a premium fuel or something to think its cool or to even brag about it.

 

Hey genius do some homework the PI swap raises comp to 11:1 lemme know how 87 octane works out on that. If your doin any type of performance work on an engine tuning for premium fuel is a no brainer and where I come from I self tuned my fuel injected race car to run on c-16 I understand the characteristics of higher octane fuels they allow a much more forgiving tuning window and much more aggressive timing. Has anyone on here ever dynoed anything? Sorry guys you don't shoot for a performance " balance" in the aftermarket hp world. Yeah and I bet a comeback will be (if someone is sharp enough to notice) that the 11 gt is 11:1comp but our trucks do not have TIVCT or a hemi style comb chamber or piston cooling jets or any of the 15 year newer pcm tech that allows this. And at $85-90 to fill my tank on 87 wtf difference is $6 more gonna make for a 50 hp increase on a truck I drive 5-7k a year ....yeah im bragging about running "premium" fuel....he'll I should fill up on my $16.20 a gallon c- 16 and ill make another 100hp!!! Gimmie a break ill go back to the corral and ask this and see if I can get someone who is able to do more than install a k&n filter and brag about your last bolt on that took 2 hours to install but you got 40 hp from it.....peace