PI swap?

tmkester · Nov 22, 2011

im new to the forum and the mustang community.. i have a 97' gt and i have really only done some stuff, cold air intake, longtube headers, catted xpipe, catback and wheels. now i was thinking about the PI swap, but should i go for the swap or something like a supercharger? or is there something els i should do? im also trying to get more bang for my buck cus im on a budget but i hear dishing out the $ for a supercharger is worth it...

sneaky98gt · Nov 22, 2011

If you are going to do anything serious to the car, you are going to need a programmer regardless. So at least plan on getting one of those at some point.

What are your overall end goals? And what kind of tools/mechanical ability do you have?

If it's a 300 rwhp car (give or take), do the PI head swap and throw in a set of cams while at it. Total cost will probably be in the $1500-$2000 range.

If it's a 350 rwhp car (give or take), get an intercooled supercharger of some sort. Probably won't be anything wrong with a used one. Total cost will probably be in the $2500-$3000+ range, depending on how much you want to spend.

If it's a 400+ rwhp car (give or take), go ahead and get an entire PI motor from a junkyard and swap in. They can be had for <$750, and you will very much enjoy the power increase. Plus, it will allow for a LOT more power when you start putting superchargers/turbos/nitrous on it. More options there, too.

If you just want a little more power for cheap, do some simple bolt-ons (sounds like you already have) as well as the PI intake and PI cam swap. Those two items can be had for <$300 pretty easily, and will net you a solid 20-25 rwhp gain. Plus, they are something average Joe should be able to do in a day. I did way back in the day before I knew anything about these cars.

OR, if you want a lot more power for cheap, there's always nitrous. You can get a complete kit with all the safety goodies for <$750, and it should put a NPI headed car into the 350ish rwhp range safely. But some people don't care much for a nitrous car.

tmkester · Nov 22, 2011

well first off thank you, and pretty much the final goal is to get the most power that i can while keeping it somewhat of a daily driver (dont want it to be strictly a track car and i need it to pass inspection) i do the work at an auto body shop and i know mechanics so i have that on my side..

N8Dogg98 · Nov 22, 2011

Good advice Will. I'd also like to say that additional power is useless if you don't have the suspension to support it (FLSFC's, LCA's, decent shocks, etc...).

If you want something fun to drive on a daily basis, you're probably better off supercharging your car. A centri unit will maintain stock like driveability and will make significant power gains > 3500 RPM's while a PD blower will net a significant torque increase across the entire RPM band (IMO PD > Centri for a daily d/t the increase in torque across the RPM band).

The problem with your 97 is you don't have many choices for PD blowers. The FRPP SVO unit can be purchased used between $2000 and $2500, or you could try and find a used KB 1.7 NPI kit (very rare... haven't seen one on e-bay or the corrall for a long time).

There's nothing wrong with the PI head/intake swap and aftermarket cams either, however you may not like the lopey idle and generally unusual behavior of a cammed car for daily driving. I know I would get irritated with my cammed car if I had to drive it every day because it's really loud for daily driving.

What are your long term plans for the car, do you want to make a fun DD on the cheap, or spend big money? With aftermarket NPI cams and a PI intake you can make impressive torque without spending a bunch of money (<$1000).

tmkester · Nov 22, 2011

a fun daily driver on the cheap, unless i have to spend big money for the big gains

N8Dogg98 · Nov 22, 2011

In that case, I'd recommend a PI intake and a set of aftermarket cams. Would cost you around $1,000 (assuming you didn't replace the timing components) and you'd likely net damn impressive gains. Have you ever had your car dyno tuned? Keep in mind if you buy a tuner and have it professionally dyno tuned it will add at least $600 to the cost quoted above ($350-400 for the tuner and $100-150/hour on the dyno).

NPI heads + cams + LT headers + PI intake = impressive N/A torque on an unimpressive stock engine. Will was running, and I'm currently running cams from Modular Head Shop. They're $600 and an additional $150 if you want him to degree them for you. I'd highly recommend this shop as Nick McKinney is probably one of the most knowledgable 2V 4.6 guys out there.

Considering your current mods it wouldn't suprise me at all if your car with stage 2 N/A cams and a PI intake could lay down somewhere between ~260-280 RWHP depending on the dyno. This combo would also have awesome torque from >2500 RPM

tmkester · Nov 22, 2011

well that sounds perfect aha i have not had it dyno tuned, with the tuner i was planing to get like an sct tuner from american muscle and having them write tunes and doing it that way, should i go somewhere els? and thank you very much for all this help

N8Dogg98 · Nov 22, 2011

The AM tuner is worthless once you add cams or a supercharger. The problem with buying a tuner from them now is that if/when you install cams or a supercharger you need to have a shop dyno tune your car to set the correct a/f ratio as well as timing. AM will not write tunes for cammed or supercharged cars because there are too many variables (bolt ons, boost, cam timing, etc...). Therefore if you take your AM SCT tuner to a dyno shop they need to charge you an additional $150 to buy the software license before they can properly dyno tune your car. Software license + 1-2 hours on the dyno = $400-500. OTOH, if you buy the tuner from them for $350-$400 it will come with the license and all you need to do is pay for dyno time. Then in the future if you install a different engine, do significant mods, etc.. you can take it back to that same shop and you won't have to pay for the software license and will only be charged the hourly fee on the dyno.

I'd suggest finding a reputable tuner in your area and talking to them about what tuning software they use and just buy the handheld from them. It will save you money in the long run. Take the time to research via local forums/car clubs on which tuner is the most trustworthy and capable of tuning your specific make/model car as well as experience with the mods you plan on installing. Hope it helps.

sneaky98gt · Nov 22, 2011

I agree with Nate on pretty much everything except the cams in stock NPI heads.

IF 260-280 rwhp is all you are looking for (and don't get me wrong, 260-280 is a LOT of fun for a DD), then yes, NPI specific cams in the stock NPI heads (along with a PI intake) is a good choice. But do be aware that those heads are going to be a huge restriction at the point. You WILL NOT make any more power NA than that. If you add boost down the road, you will be looking at 350-360 rwhp at the most, and that's it. There is no more than that unless you really push a lot of boost/nitrous through it, and that's a bad idea. If that's good with you, then go for it.

Knowing what I know now, I would have gone PI a LONG time ago. For people that don't know, I'll sum up my experience right quick.

1. Stock PI cams and PI intake on stock NPI heads. Most of the bolt-ons. Had a fun low 14-second street car. Would be several tenths quicker with gears or 5-speed.

2. Slapped an SVO blower on it at 7 pounds of boost with no other changes. Made 310ish rwhp, ran mid-high 12s consistently. Was a DAMN fun car on the street.

3. Threw a set of MHS blower cams in it (NPI head specific), as well as a slightly smaller pulley and methanol kit. Made 344 rwhp (uncorrected on a warm day), and lost a piston due to detonation less than a week later at the track. From the looks of it, it would have run 12.2-12.3 pretty easily in that trim.

4. Got a low mileage PI motor for cheap. Swapped the blower onto it, as well as the MHS NPI cams. I haven't gotten it on the dyno yet (or track), but I can say with 100% certainty that it is making way, WAY more power. I'd guess 40+ more rwhp. I'll know within a couple of weeks for sure. I'm almost positive it will go 11s with relative ease in good weather.

So, all this being known, I would have gone PI awhile ago. If I thought I wanted a blower at some time, I would just do an entire PI motor so that it doesn't raise the compression. Or if I just wanted an NA car, I would have done the PI headswap with a mild set of NA cams.

^That is just my personal opinion on the matter, and is what I would do if I had to do it all over again.

And for what it's worth, it is hardly any extra work to remove/change the heads once you have the cams out. It is literally just a matter of unbolting the exhaust manifolds from the midpipe, and removing the head bolts. THAT easy.

A PI headswap with stock PI cams and bolt-ons will make 260ish rwhp, and run low-mid 13s with a competent driver. Many people don't have a good understanding of how fast that is, but it is MORE than enough for a very fun DD. Add a set of cams while you are at it, and you're looking at 300-310 rwhp and a car that should run mid-high 12s with a good driver.

Oh, and I have NO driveability issues with my Stage II blower cams. It idles fine, plenty of torque down low, etc. I freaking LOVE rolling up to a stoplight, slipping it in neutral, and listening to it rumble.

tmkester · Nov 22, 2011

so just a question, Ford Racing PI Heads and Intake Package would something like that be worth it? plus stage ll cams?

N8Dogg98 · Nov 22, 2011

^ I don't disagree with you Will if you're looking for peak HP numbers. If you want 300RWHP, then it's PI heads on the NPI short block hands down, forced induction, or NO2. However, due to the added PTV clearance the NPI heads have over the PI heads, you're able to run a more aggressive cam on a NPI headed car. It may "only" make 260-280 RWHP, but it will make 10-15 more rwtq in the low-mid range compared to the PI headed car (don't forget that the headers are much more helpful for the NPI headed car than they are for the PI headed car d/t the poor exhaust port design in the NPI heads).

It all comes down to preference. This guy has a mildly modified NPI DD and wants to make it faster. If he didn't already have LT headers, I'd recommend the PI swap no questions asked (I too know from experience). However, w/ LT's, cams, and the PI intake that car would be a damn fast daily driver and to get there would only cost $1000.

PI heads + PI intake + gasket kit & hardware + aftermarket cams would probably cost at least $1500 (more if new heads were purchased). Then you also run the risk of buying salvage heads that are warped or need machine work, etc... From a cost and ease of install standpoint, I really don't think you can beat the NPI N/A cams and PI intake on his current combo.

wveil3v · Nov 22, 2011

Npi cams

Hey guys,

I just joined after trading my 06 gt in and after a year gettin back in the life with a 98 gt. Great writeup, matches what I am thinkin of for my 98 also. But just wondering how hard it would be to pass emissions with the agressive comp npi cams ? Mine is really a DD and passes emissions now with jlt cai and Flows on stock tune with gears. I'am def doing the pi intake and mag catted xpipe, and want to go Lts also if the ground clearance is there because it's slammed with sportlines now. Would I be switching out Xpipes and going back to stock tune every year with the addition of LTs and Cams to pass?

Thanks
Mark

N8Dogg98 · Nov 22, 2011

Where do you live? It depends on your state laws. You may get away with it if you have cats and your tuner nailed the AFR. Fortunately for me there are no emissions tests in MN

Modular2v · Nov 22, 2011

sneaky98gt said:
I agree with Nate on pretty much everything except the cams in stock NPI heads.

IF 260-280 rwhp is all you are looking for (and don't get me wrong, 260-280 is a LOT of fun for a DD), then yes, NPI specific cams in the stock NPI heads (along with a PI intake) is a good choice. But do be aware that those heads are going to be a huge restriction at the point. You WILL NOT make any more power NA than that. If you add boost down the road, you will be looking at 350-360 rwhp at the most, and that's it. There is no more than that unless you really push a lot of boost/nitrous through it, and that's a bad idea. If that's good with you, then go for it.

Knowing what I know now, I would have gone PI a LONG time ago. For people that don't know, I'll sum up my experience right quick.

1. Stock PI cams and PI intake on stock NPI heads. Most of the bolt-ons. Had a fun low 14-second street car. Would be several tenths quicker with gears or 5-speed.

2. Slapped an SVO blower on it at 7 pounds of boost with no other changes. Made 310ish rwhp, ran mid-high 12s consistently. Was a DAMN fun car on the street.

3. Threw a set of MHS blower cams in it (NPI head specific), as well as a slightly smaller pulley and methanol kit. Made 344 rwhp (uncorrected on a warm day), and lost a piston due to detonation less than a week later at the track. From the looks of it, it would have run 12.2-12.3 pretty easily in that trim.

4. Got a low mileage PI motor for cheap. Swapped the blower onto it, as well as the MHS NPI cams. I haven't gotten it on the dyno yet (or track), but I can say with 100% certainty that it is making way, WAY more power. I'd guess 40+ more rwhp. I'll know within a couple of weeks for sure. I'm almost positive it will go 11s with relative ease in good weather.

So, all this being known, I would have gone PI awhile ago. If I thought I wanted a blower at some time, I would just do an entire PI motor so that it doesn't raise the compression. Or if I just wanted an NA car, I would have done the PI headswap with a mild set of NA cams.

^That is just my personal opinion on the matter, and is what I would do if I had to do it all over again.

And for what it's worth, it is hardly any extra work to remove/change the heads once you have the cams out. It is literally just a matter of unbolting the exhaust manifolds from the midpipe, and removing the head bolts. THAT easy.

A PI headswap with stock PI cams and bolt-ons will make 260ish rwhp, and run low-mid 13s with a competent driver. Many people don't have a good understanding of how fast that is, but it is MORE than enough for a very fun DD. Add a set of cams while you are at it, and you're looking at 300-310 rwhp and a car that should run mid-high 12s with a good driver.

Oh, and I have NO driveability issues with my Stage II blower cams. It idles fine, plenty of torque down low, etc. I freaking LOVE rolling up to a stoplight, slipping it in neutral, and listening to it rumble.

WOW! Couldnt have said it better!

sneaky98gt · Nov 22, 2011

tmkester said:
so just a question, Ford Racing PI Heads and Intake Package would something like that be worth it? plus stage ll cams?

If you want all new parts with absolutely no hassle in piecing together stuff, then that's a good kit. More pricey than I'd spend, but I'm the type that would scour classifieds/craigs list/ebay/junkyards for better deals. FWIW, I spent $600 on a COMPLETE PI motor, with everything needed. Because of that, there's no way I'd spend twice that just on a top end. But that's just me. Completely your choice.

I would absolutely not run 'Stage 3' cams. They are way to much for street duties; they will not provide adequate PTV clearances, plus they will lose a LOT of torque down low.

I would run either Comp XE262AHs (a 'stage 1' PI head cam) or Modular Head Shops Stage 2 NA PI cam, probably leaning towards the latter.

LarsD · Nov 23, 2011

If you are getting that deep into the motor (pulling the heads, etc) I would go a little further and put better pistons and rods in the short block. That way you are setup in the future for more boost, etc.

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