Yep, pump gas. I discovered the compression change when doing some research. I know the pi heads on non-pi bottom end swap is common, but not everyone doing that is doing FI either. Several people said it'd be fine as long near stock boost is retained, you don't think so?It just occurred to me that you plan on using a stock 98 bottom end with PI heads. This is not a very boost friendly combination.
PI motors have larger CC dish pistons over non-pi pistons to compensate for the smaller cc combustion chamber in PI heads.
By running PI heads with non-pi pistons your increasing the compression ratio to near 10 to 1. This would be awesome combo for use with race gas but bet you plan on running pump gas on the street?! You may be able to tune it for pump gas but it will be very tempermental and sensitive to heat. I have seen it done but they are generally not daily drivers.
I know it adds a lot of time and $ but you need to consider changing pistons (with larger cc dish) which would mean rebuilding the bottom end. While your there install some forged rods and your set.
1998 Eddie Bauer / Lightning
- Thread starter SWAGGA
- Start date
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I decided to look up effective compression ratio before I speak just for a point of reference.
Xcceleration
squareroot((boost+14.7)/14.7) x Static compression ratio = Effective compression ratio
So: Squareroot ((8+14.7)/14.7) x 10 = 12.42665557 so your effective compression ratio is 12.42 to 1 at 8# of boost.
12.5 and below is considered safe for pump fuel.
Just as a point of reference my static compression ratio is about 8.65 to 1 and with 14# of boost my effective compression ratio works out to 12.08 to 1 If you plug in a stock lightnings #'s with 8# of boost and 8.4 to 1 compression it comes out to 10.5 to 1.
Going by this formula you are in the safe zone as long as you tune is dead on but it will be sensitive to intake air temps. My stang had closer to 9.5 to 1 compression with 12# boost and I can tell you it was more sensitive to intake air temps than my expy but admittedly its a completely different setup.
I personally would be somewhat concerned with your combo. But this is based on my own personal experience. Just be careful !! Remember you are running hyper pistons and stock powdered metal rods. They are not very forgiving.
There are two different trains of thought on boost vs compression ratio which I have seen a lot more of recently. Higher compression with low boost vs Low compression with high boost. If you are to believe the article posted above you will see high boost with lower compression will always make more power. The disadvantage is off boost power would be less but this is not really much of a concern with a roots blower as it will have instant full boost regardless of rpm. Ever see a top fuel car launch off idle??
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We'll rock it and see what happens lol. Aren't some of the newer fords like 11:1 with FI on top? What type of stang did you have? I've heard the older SBF (302 etc) were more sensitive to compression & boost than the modular motors.
I will definitely be sticking with stock pulleys. I've got reservoir for the IC coolant that's about 3-4 times big as the stock one, & putting dual fans on the HE. That should help intake temps. I believe porting the blower has a positive effect on intake temps as well.
I'd like to build a bottom end down the road... planned of course, I'm not wishing anything unexpected on myself.
I will definitely be sticking with stock pulleys. I've got reservoir for the IC coolant that's about 3-4 times big as the stock one, & putting dual fans on the HE. That should help intake temps. I believe porting the blower has a positive effect on intake temps as well.
I'd like to build a bottom end down the road... planned of course, I'm not wishing anything unexpected on myself.
We'll rock it and see what happens lol. Aren't some of the newer fords like 11:1 with FI on top? What type of stang did you have? I've heard the older SBF (302 etc) were more sensitive to compression & boost than the modular motors.
I will definitely be sticking with stock pulleys. I've got reservoir for the IC coolant that's about 3-4 times big as the stock one, & putting dual fans on the HE. That should help intake temps. I believe porting the blower has a positive effect on intake temps as well.
I'd like to build a bottom end down the road... planned of course, I'm not wishing anything unexpected on myself.
Yep.
But between direct cylinder fuel injection, use of wide band sensors, more sophisticated processors and just overall engine improvements they can safely run higher compression. None of which can be applied to our older 2v 5.4's.
Just do a search on fords 3.7L ecoboost technology or fords new 5.0 coyote motor. Much more magic...
I had an 89 LX mustang. Its in "Other Vehicles" section in this forum.
Tell them they need to put the throttle to the floor..... or maybe release the parking brake!!
Seems a bit lower than I would expect. Thinking stock number minus about 15% for drivetrain loss. 1998 5.4 expy @ 230hp * .85 = 195 ish hp.
Seems a bit lower than I would expect. Thinking stock number minus about 15% for drivetrain loss. 1998 5.4 expy @ 230hp * .85 = 195 ish hp.
97EddieExped
Member
Well if its a Mustang Dyno it's conservative and that could be why the numbers look low. If its a Dynojet idk.
My mom's PI motor put down 195 stock. On this one, non-pi 98 I hadn't even checked the k&n drop since I've bought it, even the gotts mod wasn't done, the flowmaster was welded in with stock pipes, and the tune was an out of the box, extremely mild one for a stock expedition. I'd feel more comfortable calling it stock than modded given the level of the mods.
Here's day 1 progress after the initial dyno, none of which I did. Next step is removing stock heads (notice the mouse nest on top of the block, there was a crispy mouse in there too)
Advance gave me the wrong water pump... the one I need is $60 more expensive, isn't stocked, and I had to pay extra shipping to get it here. I ordered the gasket set from Rock Auto (felpro), and it's missing a couple of gaskets from the set... we'll see how that plays out. If I can get the missing ones locally for cheap I'll let it slide, if not, I'll call their customer service, but disappointed to say the least.
Here's day 1 progress after the initial dyno, none of which I did. Next step is removing stock heads (notice the mouse nest on top of the block, there was a crispy mouse in there too)
Advance gave me the wrong water pump... the one I need is $60 more expensive, isn't stocked, and I had to pay extra shipping to get it here. I ordered the gasket set from Rock Auto (felpro), and it's missing a couple of gaskets from the set... we'll see how that plays out. If I can get the missing ones locally for cheap I'll let it slide, if not, I'll call their customer service, but disappointed to say the least.
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My mom's PI motor put down 195 stock. On this one, non-pi 98 I hadn't even checked the k&n drop since I've bought it, even the gotts mod wasn't done, the flowmaster was welded in with stock pipes, and the tune was an out of the box, extremely mild one for a stock expedition. I'd feel more comfortable calling it stock than modded given the level of the mods.
Here's day 1 progress after the initial dyno, none of which I did. Next step is removing stock heads (notice the mouse nest on top of the block, there was a crispy mouse in there too)
Advance gave me the wrong water pump... the one I need is $60 more expensive, isn't stocked, and I had to pay extra shipping to get it here. I ordered the gasket set from Rock Auto (felpro), and it's missing a couple of gaskets from the set... we'll see how that plays out. If I can get the missing ones locally for cheap I'll let it slide, if not, I'll call their customer service, but disappointed to say the least.
Your dyno #'s should look much better when she is done.
Ummm..... cooked mouse. Looks like it got cooked before it chewed up any wires anyways.
onlyexilove
Full Access Members
Looks like a killer build. I also did the PI head swap on my 98 4.6 XLT setup and she runs like a beast now. Running BBK shorty headers, Borla muffler with stock piping and cats, 03-04 Expy intake, Ford Racing heads and Spectre Intake pipe. Would love to see how all of this turns out with yours. I am looking at charging mine later on down the road too. Question I have is yours the 5.4? I am hoping that the lightning setup will work for the 2V 4.6 Romeo setup.
Lol, yeah he didn't pick the best of places to build...Your dyno #'s should look much better when she is done.
Ummm..... cooked mouse. Looks like it got cooked before it chewed up any wires anyways.
Yeah I'll post my complete setup soon, I stayed pretty stockish on exhaust for now, I did upgrade headers as the stock manifolds are horribly designed.
Yes I do have the 5.4. The lightning intake will bolt to both romeo and windsor heads, you just need the correct valve covers. In fact, my heads are romeo heads from a 4.6 mustang.
I finally got to lend a hand yesterday and get some grease on my hands:
Down to the block:
New assembled heads set on block:
They're torqueing them down to spec today... looks like that may be the one of the harder remaining parts.
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The lightning setup will not work with a 4.6. While the heads are interchangeable the intakes are not. The 5.4 block has a taller deck height which requires a wider intake vs a 4.6.
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Ah, so the lightning lower intake won't work on 4.6 motors? It is pretty "deep" for the IC to set in.
Lol, yeah he didn't pick the best of places to build...
Yeah I'll post my complete setup soon, I stayed pretty stockish on exhaust for now, I did upgrade headers as the stock manifolds are horribly designed.
Yes I do have the 5.4. The lightning intake will bolt to both romeo and windsor heads, you just need the correct valve covers. In fact, my heads are romeo heads from a 4.6 mustang.
I finally got to lend a hand yesterday and get some grease on my hands:
Down to the block:
New assembled heads set on block:
They're torqueing them down to spec today... looks like that may be the one of the harder remaining parts.
Can't wait to see/hear her running !!!!
You can see the difference in the valley between the heads in the photo below..
Good info.
I didn't get to help any today... work's been a little chaotic... but the guys got really far.
Left to do:
Heat exchanger/fans
IC pump
Coolant system hoses
Gauges
Bolt on JLT intake
Tune
If all goes well, we may get to start it tomorrow with a base lightning tune to move it to the dyno room... I'm just praying everything is well, which it should be!
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