Turning a 4.6 into a 5.4

S

stang671

New Member
Dec 21, 2006
18
0
0
#1
Hey,
Does anyone know if it's worth the time to convert a 4.6 into a 5.4 i was looking it up in different books and it showed that the only difference is the stroke...not to sure does and one have a comment on that and do you think it's worth it...thank you for taking the time to read this and comment...
 

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#2
going from a GT to a sohc 5.4 no. that is the cheapest and easiest, but no its not worth it the stroke will add bottom end torque and slight HP across the band.. not enough.

what makes a 5.4 worth it? going 4v. its been proven that a high rev 5.4 4v with the right parts can get near 500 hp. the only issue is its expensive, and requires 1-2 custom parts. still wrestling over turbo, KB, or 4v 5.4 myself... still have to finish ym front suspension then i can deal with power.

Torinalth
 
#4
Going from a 3.543" stroke to a 4.165" in a 4.6 block may prove to be very difficult, if not impossible. That is an additional .622" worth of stroke that would have to be adressed by way of clearancing and choosing maybe a custom rod/piston to keep the piston to deck clearance manageable. I'm not sure this can even be done using an iron 4.6 2V block.

I think if you are wanting more than 302 cubes with a stock iron block, you would be better off to start with a 5.4 block.

Then of course you could also have an aluminum block sleeved to achieve more cubes. Livernois did a re-sleeved 331" stroker.
 
#5
you can get 304 or so out of a 4.6 with stroker cranks... going 5.4 does require the higher deck 5.4 block, ala F150 for Sohc heads, or the navigator NVI block for DOHC heads. playing with a frankenstein engine is not that hard... but going 5.4 puts you into the vast minority of premade aftermarket when having to make sure it works with the mustang body.

honestly its cheaper and easier to do a cobra based engine and you only lose about 50 HP and about 75 torque off the fully built 5.4 to the fully built 4.6... and the cost... well... anytime custom is removed from the equasion.... anyhow...

Torinalth
 
#6
whether it's worth the time and money or not sorta depends on your goals...

if you want a no-holds-barred race car/street car, it's probably not worth it....if you're interested in replacing a worn out or broken 4.6 and aren't looking to get much more than 275/300hp, the 5.4 is a cheap way to get a TON of torque...



edit: sorry I read it to mean replacing a 4.6 with a 5.4, if you want to try and turn a 4.6 motor into a 5.4, no that won't work at all
 
#8
actually i'm just trying to find out the best way to get some hp out of it....i'm stationed in san diego and i'm going to send it to a shop down there and i'm just lookin at what can all be done wit it...right now the plan is to get it rebuilt from bottom up and but a KB on it possiable the 2.6(it think is the one now) one shop told me that they don't make the 2.1 anymore so i'm not to sure but...that's what i plan on doing i'm wondering as well what's the most boost i can put runnin on pump gas and i've been told that it depends on the tune...so i'm not to sure bout all that my goal is about 500-600rwhp...
 
#11
Well built engine, possibly stroker, with some good blower cams and the 2.6L KB... that'll get you to 500 no problem.

The 2.1L is the new base blower for the 4.6L 2v, replacing the old 1.7L. The 2.6L is KB's new tuner supercharger, replacing the old 2.2L I think.
 
#12
stang671 said:
but would i need to do that to make that amount or can i just do it wit a 4.6 wit the KB....or should i try to find a 5.4 and do it to that....and does the 5.4 need to b a 4v or can i do it wit a 2v
Click to expand...

You could just have your 4.6 block bored .030" over then used a 3.75" forged Cobra crank. That would give you ~302 cubes. Go with a nice combination of forged rods and pistons. Then in my opinion you should go with a centrifugal supercharger. It will be much more fun to drive on the street and will get much better MPG (if you care about that). Additionally the centrifugal charger will be able to make way more power than a KB, especially above 3500 RPM's. And I don't know about everybody else, but I cannot stand the whine of a KB. Sounds horrible like a little baby being tortured.:p The centrifugals have a slight whine, but it's a totally different sound and not near as pronounced.

There isn't a rule of thumb as to how much boost you can run on pump gas, a lot of it will depend on your effective dynamic compression ratio. Anytime you talk compression ratios on a boosted motor, you talk in terms of "effective." Obviously the cylinder pressures will be much higher under boost than N/A, so your cam selection will have a lot to do with it as well as how much boost the motor will see. Another big factor will be the efficiency of your supercharger/intercooler. Cooler inlet temps, realtively low effective DCR, good tuning, and the right plugs all combined can allow for a substantial amount of boost on pump gas.

600 RWHP is a breeze on pump gas with the right combination.
 
#14
If your 2.6L goal is around 530-540 with only upgraded 8.1 forged pistons and rods on good pump gas at 14-15 psi, this can be achieved without the cams, heads and headers (we've only seen 8HP from headers). Just drop in the Cobra tank and pumps with 55lb injectors and the stock fuel lines. THAT is still A LOT OF HP for the street. Enough to run 120 in the low to mid 11's. Again - a stock '03 Cobra is 360. Add the Kenne Bell 2.6L at 15 psi and it makes 560HP! Our dyno tests indicate that the 4.6 GT 2V engine with heads and cams makes 30 more HP (590HP) than the Cobra at 15 psi. That should give you an indication of the 2V potential.

this is what they have posted on their web site...what do u think....
 
#15
i personally disagree with the comment of more fun going to the centri... i dont like to drag, so i want all the power i can get at whatever RPM i am exiting a corner in... then there is the belt slip/shred issues depending on blower and pulley size.. anyhow, whole different thread with that..

what do you want to do? do you just want power? what kind of power? cheap power? all necessary questions before you jump on the 5.4... to get the raw power is costly.. but can very benificial... blowers are easier, mildly cheaper depending.. but all have their issues.

Torinalth
 
#16
my main goal is to get 550-600rwhp and still run on pump gas....if i can do it in a 4.6 2v then i will.....i want to stay streetable....and be able to pull up to just about any car and smokim...that's my main goal...and i went to a shop and saw a 04 (i think) Gt 2v that just got finished with KB install and with a rebuilt motor not sure what his hp is but the guy at the shop said that is a good setup...so if i could get some imput before i commit myself to either way...and that's y i was wondering if i should go to a 5.4 or is it not worth the time and money...
 
#17
I've driven many different cars with both centrifugal and roots/screw type superchargers. If all you care about is melting the tires off the line then go with a roots/screw type charger.:) If you want to hook, then experience a much steeper HP curve that will give you much harder acceleration, go with a centrifugal supercharger, they are so much more fun on the street.

Take a look at a typical HP curve for the various blowers:
View attachment 413603

Typically at about 3500-4000 RPM the centrifugals will blow away (pun intended) the roots/screw type superchargers. The typical HP curve is inherantly steeper on a centrifugal blower as opposed to a roots/screw type charger. This equates to better traction off the line then obviously a much harder acceleration throughout the entire RPM range due to the inherantly steeper HP curve. That equates to winning races and having more fun.:nice:

Roots/screw type blowers work well with dedicated drag cars because they don't expereince the range of RPM that a street car will. But on the street, and trust me, you will be much happier with a centrifugal charger.

Shoot me another PM if you have any questions or need any help putting together your combo. I'll be glad to help in any way that I can :nice:
 
#20
getting to 550-600 rw all motor with any mod is going to cost a fortune.

you will need BB(risky at that power level)just ask Al he can tell you himself.
the stock 5.4 steel crank prepped

the best rods,pistons and all out technology out there

GT heads ported by Al or his equal.

scott at VT makes > 600 with proprietary stroke and BB. there is a risk of blowup with BB.

and you need to turn it 7500-8200 like Al and scott do.

you need a nascar style prepping on the carbed intake. fuel injection will cost you the motor.

custom headers for peak power, seriously radical cams. i have heard Al's run with my own ears, and it's radical.

how much? 20g's maybe more. just for the motor.

or KB with forgings and get it easy. Tim at MPH has Guaranteed a close friend 450 to the wheels safely with his stock low end and a mongoose kit. you choose.

i'm for all motor, unless you want more than 330 can produce. then KB it. or the equal.
 
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