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Discussion Starter #141
Makes sense; the compression boost will add some horsepower as well.

You might need a tune to take advantage of it, tho.

9.35 to 10.44 compression ratio boost, from going to PI heads on NPI block.
 

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Hmm, 10.38 IIRC. :)

Definitely needs a timing change though. It "might" run on 93 without, but is risk of melted pistons worth saving the money for the tune, especially when considering the other benefits the tune gives? I managed to get mine to run on 87 but quite a few of the cells are running less timing than stock - mostly low load/RPM. :)
 

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Discussion Starter #143
I used the compression calc in the forum link; that's what it gave. :)

Risk of melted pistons is not worth it at all; and the extra HP from 93 and a proper tune is well worth it.

If E85 were more common here, I might consider going that way, but there are areas with no E85 that I drive thru.
Several places replaced their E85 pumps with 100% gas pumps; cool, but most of them are 87, and I need 91, lol.

My tunes rattle with 87, lol.

Oh, if you do a headswap, look into the "Crack Pipe" cooling mod; it keeps #7 from being the cylinder that rattles first. :)
 

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Makes sense; the compression boost will add some horsepower as well.

You might need a tune to take advantage of it, tho.

9.35 to 10.44 compression ratio boost, from going to PI heads on NPI block.
Hmm, 10.38 IIRC. :)

Definitely needs a timing change though. It "might" run on 93 without, but is risk of melted pistons worth saving the money for the tune, especially when considering the other benefits the tune gives? I managed to get mine to run on 87 but quite a few of the cells are running less timing than stock - mostly low load/RPM. :)
Well, considering the other two mods I'm doing, if I were to keep her down longer and get the heads, it'll just be another thing to add to a single tune file when the time comes ;)

Also, would the tune allow to run 91 octane only on 19# injectors? Or would I need 24# injectors as part of a PI swap?
 

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Discussion Starter #145
It's close; at wot the 19lb injectors are ~85%; I decided that was too close for me.
It really should be fine.

I have a refurbed set of 24# injectors I'd part with; new orings, screens, and have had injector cleaner ran thru them.

I cleaned and tested them last summer.
(I ran them at 50% duty cycle at 8V, while running a half can of injector cleaner thru them.)
The other half a can went thru the green ones. :)
 

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I’ve done valve seals without an air compressor, as long as each corresponding piston is at TDC the valve isn’t going to fall in past the point you can’t grab the stem and pull it right back up.

I don’t think the compression bump is worth it for PI heads. Cams+intake on npi longblock = PI motor without the hassle of swapping heads with the engine in the car(it’s a pain in the ass). Plus You absolutely 100% need a tune with them to avoid pinging since npi combustion chambers use so much more advance, and you can’t run 87. I’d just replace the valve seals personally, but there’s no guarantee valve seals are even the source for your smoke puffs.
 

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I also adapted an XLS spreadsheet to give some great injector data for writing tunes. You can play with it to see what your injector duty cycle would be with various HP/flow combinations, to see what works best. Forum won't let me upload it as an attachment but I can PM you a link to it in my dropbox. For my engine/combo, this is what it looks like...

37095
 

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I’ve done valve seals without an air compressor, as long as each corresponding piston is at TDC the valve isn’t going to fall in past the point you can’t grab the stem and pull it right back up.

I don’t think the compression bump is worth it for PI heads. Cams+intake on npi longblock = PI motor without the hassle of swapping heads with the engine in the car(it’s a pain in the ass). Plus You absolutely 100% need a tune with them to avoid pinging since npi combustion chambers use so much more advance, and you can’t run 87. I’d just replace the valve seals personally, but there’s no guarantee valve seals are even the source for your smoke puffs.
So in your opinion, I already have a PI engine, minus the tune?

Why do you say that the compression bump isn't worth the work of doing full PI top end?

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With PI cams and PI intake on a npi headed longblock the power and torque is indistinguishable from a stock PI engine. The heads flow almost identically.

The Compression bump adds a tiny bit of power, we’re talking under 10 for this configuration, but for the physical effort of swapping heads, the monetary cost of buying heads, gaskets/bolts and tune, and cost at the pump of only being able to put in 91-93 octane is absolutely not worth it to me, you can make up for it and then some elsewhere. If you had a 94-95 with the bad heads it would be a different story, but I never recommend headswaps on 96-97s with the F5 castings
 

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However... a compression bump's gains add that ~10HP pretty much everywhere along the curve. The PI intake only adds power over 4000 but sacrifices a little torque under that, and that the PI cams add that back along more or less the entire curve. Whether it's worth the labor or not... definitely depends on the circumstances. If you never intend to upgrade to ported or TFS heads, it's easier to justify.

All depends what you consider is worth it.

Also - in case you missed it - you CAN run 87 octane with PI heads on the NPI rotating assembly. I started doing it on the T-bird last year because I refuse to keep paying 30-40% more for 93 than 87. Whether it's any more power than 87 with NPI heads... who knows. But if I ever go back to the dyno or strip, I'll find out. :)
 

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He’s going to have a manual transmission at some point, and that ~10 horsepower across the board deficit will be made up for in it. Like I said, for the costs/effort finding it elsewhere is way better.

What cams are you using Brandon? Aftermarket cams allow lower dynamic compression than PIs and consequently are more friendly to lower octane than PIs. But yeah, I pulled some timing to run 87 on my 4V with advanced Cobra cams and it seems happy
 

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Not disagreeing with that - it is a lot of work for 10 HP. :)

Mine are Bullet's stage 2P cams. It's a little temperamental with the exh/int valve overlap (dynamic presence of residual EGR screwing up my low tp/rpm timing) but I'm hoping to resolve that with the headers.
 

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Discussion Starter #153
Brandon, that's an awesome spreadsheet; any chance you'd email that to me?

I'll find a way to make it up to you. :)
 

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Any of you guys know how to buy parts out of mexico? I cant even find a website for me to look at them.
 

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With PI cams and PI intake on a npi headed longblock the power and torque is indistinguishable from a stock PI engine. The heads flow almost identically.

The Compression bump adds a tiny bit of power, we’re talking under 10 for this configuration, but for the physical effort of swapping heads, the monetary cost of buying heads, gaskets/bolts and tune, and cost at the pump of only being able to put in 91-93 octane is absolutely not worth it to me, you can make up for it and then some elsewhere. If you had a 94-95 with the bad heads it would be a different story, but I never recommend headswaps on 96-97s with the F5 castings
However... a compression bump's gains add that ~10HP pretty much everywhere along the curve. The PI intake only adds power over 4000 but sacrifices a little torque under that, and that the PI cams add that back along more or less the entire curve. Whether it's worth the labor or not... definitely depends on the circumstances. If you never intend to upgrade to ported or TFS heads, it's easier to justify.

All depends what you consider is worth it.

Also - in case you missed it - you CAN run 87 octane with PI heads on the NPI rotating assembly. I started doing it on the T-bird last year because I refuse to keep paying 30-40% more for 93 than 87. Whether it's any more power than 87 with NPI heads... who knows. But if I ever go back to the dyno or strip, I'll find out. :)
From previous thread readings of PI intake and cams, I should be ~25HP over stock w/o tune. From other previous thread readings, a full PI top end should be ~60HP over stock w/o tune.

Or is this wrong?

He’s going to have a manual transmission at some point, and that ~10 horsepower across the board deficit will be made up for in it. Like I said, for the costs/effort finding it elsewhere is way better.
The part that concerns me most with going MT are the half shafts. Someone on the FB TCCOA page stated that there are hardened MK-VIII half shafts. Is there a part number for those? How are those identified? I'd be more inclined on finding those over shelling out nearly $2k on DSS half shafts, lol.

Or do these not exist?

Curious so I could have correct info in my ThunderMustangMarkBird project, lol.

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60 horsepower is grossly wrong. Its about about 30 for either PI cams/intake or PI engine swap and about 40 for Heads/cams/intake from the compression bump. People pulling out 60 are talking out their ass and/or using the published figures Ford uses that are pure bunk. YOU NEED A TUNE with PI heads so there's no way to even pull off that claimed figure, at least without race gas.

Dont worry about the halfshafts unless you're running drag radials. Mark VIII halfshafts are supposedly hardened, yet my Cougar still has the factory tags on them and the part numbers are the same as the Lincoln, so if they are hardened MN12s got them too. IIRC they're claimed to be hardened where they never fail anyway, when they break its usually at the outer or inner splines

Throw away all info gathered from the FB group ;)
 

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Discussion Starter #157
TrunkMonkey twisted his right side HalfShaft off, with 500+hp and sticky tires.

We won't have to worry for a while. :)

Supposedly, the right side Mark HS is thicker metal than the other side; they used to be a different part number when I first started into this.
The front control arms had different bushings for the SC cars too, but those have been gone for at least ~20 years.

:)
 

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Yeah, I wouldn't worry about the halfshafts. Virtually all the time they break with the power levels we're talking about it's because of wheelhop, often from worn out bushings - just make sure you've stiffened up the IRS with delrin or at least poly if you decide to go play seriously.
 

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60 horsepower is grossly wrong. Its about about 30 for either PI cams/intake or PI engine swap and about 40 for Heads/cams/intake from the compression bump. People pulling out 60 are talking out their ass and/or using the published figures Ford uses that are pure bunk. YOU NEED A TUNE with PI heads so there's no way to even pull off that claimed figure, at least without race gas.
So what's the whole point of a PI top end? I have been under the impression these last 5-ish years (of the 7 I've been a member) that a PI top end essentially nets you a Mustang GT (1999 - 2004) engine. And we know that those put out 260HP. Or have I been entirely mistaken all this time?

Or are you talking WHP numbers while everyone else is talking BHP numbers? Because we all know that manufacturers don't put out WHP numbers.

Dont worry about the halfshafts unless you're running drag radials. Mark VIII halfshafts are supposedly hardened, yet my Cougar still has the factory tags on them and the part numbers are the same as the Lincoln, so if they are hardened MN12s got them too. IIRC they're claimed to be hardened where they never fail anyway, when they break its usually at the outer or inner splines
I guess time will tell. Everyone here knows I'm beefing up my suspension. While eliminating / reducing wheel hop hasn't been my intended goal of my suspension upgrades, it will definitely be a result of it. Worst case scenario will be that I have a set of half-shafts ready to go should I need them.

Throw away all info gathered from the FB group ;)
So throw away info from people like Rod (Racecougar) as well? I mean, there are a few people there who everyone looks up to, such as Rod, Ralph, and Woodman, to name a few but still. There's a few people there that I will listen to. Others though, yea, I'll agree with you.
 
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