Intake Port Configuration technical debate

[Rara]

This thread is here to discuss the relative pros and cons of the various intake port configurations possible with the 3.0L and 2.5L parts. As well as custom stuff.

A couple of configurations to get things started.

1. Stock SVT 2.5L Split port. Split port 2.5L heads, w/ IMRC in the LIM and stock SVT UIM.

2. Stock 3.0L oval port. Oval port 3.0L heads, stock plastic oval port LIM, and stock plastic UIM (taurus or escape, though, the later escape versions are the best of these)

3. ST220 3.0L oval port. oval port 3.0L heads, ST220 aluminum oval port LIM, ST220 aluminum UIM.

4. Hybrid port. oval modified port 3.0L heads, split port IMRC LIM and stock SVT UIM.

5. Reverse hybrid port. split port 2.5L or 3.0L heads, custom LIM, oval port plastic UIM.

6. Burrita Hybrid. oval port 3.0L heads, Burrita LIM, stock SVT UIM.

These should get people started, if you can come up with other feasible configurations, feel free to mention them. Post your relative pros and cons for each style that you feel you have good information about. Please back up your comments as best you can. Data is preferred, but I understand hard data is tough to come by on this subject, so solid technical reasoning is allowed as well. Simple regurgitation of what someone else has said is not allowed, unless you can back up the tech on your own.

 

[Bradness]

Great timing and hopefully there will be some kind of consensus supported by proper data. I assume we're looking at HP/TQ figures after tuning...

My 3.0 was going to be an oval port head matched to the stock SVT LIM/UIM c/w SVT cams (option 4) but I'm open to proven ideas/info.

Let the games begin!

 

[jeromio]

If you leave pure performance aside, I would suggest, from painful experience, that the full oval (3.0L heads and intake) is to be avoided due to complexity. I went this route b/c I presumed it would be less work and less risk since I wouldn't have to open up the long block to swap or modify heads. (I was also thinking of economy since I would be able to use 87 octane with a "stock" Escape 3L.)

But this is a pretty complicated swap with lots and lots of head scratching and bugs to work out. And I have some experience doing motor swaps (eg http://240z.jeromio.com/ls1 for just one example). If you can use the 2.5L intake, I think it would make things very much easier. Plus you can keep IMRC and the stock tune which will save some dollars. Cars up on jack stands don't perform very well...

 

[warmonger]

Amen to that! It's better to figure out the working solution that gives you 80-90% of the "theoretical" best HP than to leave the car on jack stands for Eons while you search and save for the "Best" solution to give you the 100%. You can at least enjoy it while you search for ways to improve what you've got and it gives you the benefit of a continually interesting hobby.

From my point of view there has to be a quantifiable way of comparing these setups listed based on prioritization.
HP/TQ is the first priority you might say....till you look in your wallet and find out that in reality the first priority is $$$.
Then there are other things; like can you fix it once it's built or is it a 'on-off' part that you have to cross your fingers on that it stays working and that basically no one else can maintenance it. Who's doing the install and (back to money or time) what's that entail?

So here are your topics of prioritization:

-Performance
-Money
-Installation
-Reliability
-Sustainable maintenance
-Availability


You put a weight on those priorities and you might surprise yourself on what really comes out of it.

For my money the split-port intake system to Oval-port hybrid is the cheapest and easiest and gives very good performance.

I did go over these in another recent post this year in the 3L forums. I'll try to find it and post the link.

 

[warmonger]

Here is what I posted before along with the link to the thread.
http://www.contour.org/ceg-vb/showthread.php?t=15599&page=3

There is a lot of truth to the statement that mod'd cars are worth LESS money than a clean factory model. However it is not always the case with the SVTs. A well done hybrid whether oval heads or 2.5 heads is going to look like stock and feel better than stock in EVERY way, including getting essentially the same gas mileage for most drivers.
A full 3L drop-in in an SVT is a frgn disgrace IMO! You buy it if you want to but that would definitely cut resale value.

There is no single better hybrid package over another as long as each one is thought out and built to the achieve the goals you want. If you assume a stock block/piston/rod assembly, then you can run across many reliable combinations.

A hybrid 3L with 2.5L heads can come with High or low compression and 2.5L or 3L valves in the heads, 4 different combinations. A big portion of the success of the 2.5L hybrid is accomplished through proper porting of the intakes and the heads and installation of the 3L valves. This is actually the most superior head setup for the 3L hybrid because the intakes are true split ports all the way down and complements the factory system and tune. It can come in high compression for NA mods and low compression due to combustion chamber reshaping for boosted engines. Basically 11.25 all the way down to ~9.8:1 compression. NO ONE has proven that the heads are truly related to oil starvation on the big-end bearings even though the theory is out there.

An ovalport hybrid can come with 10:1 down to 9.8 or so compression with a little combustion chamber work and the head is quite opened up to flow well right from the factory. A proper port matching of the intakes and it will work well with less labor, though there is some debate about how well the secondaries work. I've got enough datalogs to show that the ovalport works very well though by comparison not as well in the low rpm ranges as the split-port 2.5L hybrid with big valves.

So I rank the swaps in terms of simplicity, peak power, overall Broad Powerband, and cost/labor.

-3L/2.5L Hybrid with big valves and portwork=best in broad powerband and equal to any other NA motor in Peak power. Highest cost in labor/time.
-3L/2.5L hybrid with no valve or portwork= cheapest and low cost in labor with the lowest peak power returns but reasonably broad powerband. Can be done with just a used 3L short-block.
-3L oval with 2.5L intakes minimal portwork= #2 choice with good overall powerband and peak power. Low cost but still requires a decent 3L Long-block, simple labor.
-3L oval with 2.5L intakes and extensive porting= equivalent to 3L/2.5L hybrid with big valves, except the low end portion of the powerband is a bit lower than the true hybrid from examples of dynos seen so far.
-3L drop in is a full 3L motor and basically it is a Taurus motor. More modifications to the CAR to accept it (none to the motor), cheap but some labor and fabrication. Power is middle of the road due to stock 3L cams and intakes and definitely not great on the top end. Engine bay less attractive and obviously not stock.

 

[BurritaSVT]

If you leave pure performance aside, I would suggest, from painful experience, that the full oval (3.0L heads and intake) is to be avoided due to complexity. I went this route b/c I presumed it would be less work and less risk since I wouldn't have to open up the long block to swap or modify heads. (I was also thinking of economy since I would be able to use 87 octane with a "stock" Escape 3L.)

But this is a pretty complicated swap with lots and lots of head scratching and bugs to work out. And I have some experience doing motor swaps (eg http://240z.jeromio.com/ls1 for just one example). If you can use the 2.5L intake, I think it would make things very much easier. Plus you can keep IMRC and the stock tune which will save some dollars. Cars up on jack stands don't perform very well...

Everyone that has done a full 3 liter swap out said it was not easy as people make it out to be I can get to three different post recently stating the hard install it was. And we know the oval port UIM is fragile and harder to tap into for modding and obviousily can not be maxxed honed out like cast. The benefit is heat transfer is low and the material is lighter than cast aluminum. The Flow is the same as split port SVT or less but better than the non SVT lower intake. you have to modify the fuel rail, relocate the EGR valve, TB brackets, wiring etc.....still costing about 200-300 time and labor or more.

The second best is to keep secondaries in while using the 2.5 SVT LIM UIM with oval port heads ported to match the split ports. You have the flow of the SVT Manifolds but still bottles necks down a hair at the valves. This requires welding and removing heads and three days of grinding and matching. Cost as much as $500-600 in parts and labor and time.


The third best is to use my LIM Mod that has the same flow as oval port using the tuned UIM that has proven to flow great numbers and is made for high reving motors. (tuned) The part will run about $300-$400 and will be direct swap less time equals less labor and safe (fuel line) netting the same power as the oval port full swap

The best option but very costy would be to use the SVT heads swap 3 liter valve port it and add rear drains to the block. Then send it to a professional to grind out the combusion chamber to match the 3 liter cylinder which would drop the CR right about 10:1. costing nearly $1200-$1500 with using the SVT UIM LIM and Cams. Use the 2.5 liter crank get it balanced to a 3 liter and let it scream too 8K easy.

Power in better to worse in my eyes

*3 liter hybrid> 2.5 heads ported> 2.5 Crank ported heads> 3 liter valves> rear oil drains> SVT Cams

*3 liter> oval port heads> SVT LIM UIM> secondaries> SVT Cams>

*3 liter> oval port heads> SVT cams> LIM MOD to oval> SVT UIM

*3 liter> oval port heads> SVT cams > Oval Port LIM UIM

*3 liter> Oval port heads> Escape cams> oval port LIM UIM

3 liter > oval port heads> SE cams> oval Port LIM UIM

3 liter > oval port heads> SE cams > SE UIM LIM

now in most expensive to less including parts and labor

*3 liter hybrid, 3 liter valves in the SVT heads, 2.5 balanced crank, SVT cams

*3 liter oval port heads,2.5 svt UIM LIM ported, SVT cams

*3 liter oval port heads, 2.5 SE UIM LIM ported SE cams

*3 liter oval port heads, LIM MOD transistion, SVT cams or SE cams

*3 liter full swap

the last four or close to the same price but the only difference is how much time or labor you are being charged J

 

[Pudmunkie]

For a splitport to ported oval port head (or possibly even one of joey /toms adaptors) would it help to lower the RPM at which the secondaries open since you dont have the benefit of the long / short runner all the way into the head (thanks for that thought rara)

 

[Bradness]

Use the 2.5 liter crank get it balanced to a 3 liter and let it scream too 8K easy.

I'm curious... What's the difference between the cranks that makes a 2.5 superior? I assume you're referring to balancing the complete rotating/reciprocating asembly (crank, rods and pistons).

 

[BurritaSVT]

I'm curious... What's the difference between the cranks that makes a 2.5 superior? I assume you're referring to balancing the complete rotating/reciprocating asembly (crank, rods and pistons).

There are less holes in the reciprocating lobes dince they are filled to counterweight the heavier mass which is less oil drag. Plus the SVT were handpicked cranks from the assembly line which makes me feel better about the crank. But I have no sure facts on why besides a race team that has a 3 liter turning up 8k for racing using the same configuration.

 

[Rara]

by no means complete, but a few of my thoughts on the matter.

Config #1
First, the split port configuration is clearly superior for flow, it has more flow area in total, and at lower engine speeds with the IMRC closed you definately maintain port velocity improving cylinder filling, and since inlet flow is only from one side, you get more tumble in the chamber theoretically improving fuel mixing and hopefully efficiency. The two key downsides to the split port geometry on the stock CSVT are the smaller valve sizing in the head (which can be fixed) and the plenum volume on the stock manifold. The stock CSVT manifold has plenums that are barely adequate for a stock SVT (for packaging reasons) let alone for a heavy breathing 3.0L. The other downside to split port (unless you find a set of old split port 3L heads and run an elec. water pump) is the hybrid issues from using the 2.5L heads. The need to plug oil passages in the block, the lack of the same oil passages in the heads, supposedly there is another issue with the oil passages as well, but I honestly haven't built I hybrid so I don't know. And then there is the squish band issues of putting the 2.5L chamber over the 3L cylinder; couple that with the resulting high CR, and it makes for some very big question marks for how prone the combination is to cylinder hot spots, and poor fuel conversion efficiency because of all the crevices.

Config #2 & 3
Then there is the full 3L w/ oval port and manifold. Much simpler from an engine build standpoint, but potentially a lot more confusing for the average shadetree when its time to hook everything up to the motor in the car. The oval port in general is a compromise in order to simplify and make the overall design cheaper and easier to produce for ford. Flow is still pretty good overall, but not quite as good as the split port, BUT the oval port designs get the larger valves, and they have plenty of plenum volume to keep up with flow demands at higher rpm, especially when you look at the later Escape manifold and the ST220 manifold.

 

[Rara]

Config #4
The Hybrid-port using the the oval port heads modified to mate up to the split port upper and lower with IMRCs intact. Seems a bit off from a performance standpoint to me, and I would think the main attraction would be convenience of installation. You lose most of any benefit gained from the IMRC's because when they are closed all the air just tumbles back up behind the closed butterfly at low RPM instead of tumbling in the port. Further, you have the offset injector (though, this may be a good reason to retain the IMRC) and if you use a 3L or other wide spray pattern injector (yes, there are differences in the spray patterns) half your fuel will just be wetting down the port walls. If you have an offset injector mounting, be sure to use the original injectors, or injectors of the appropriate size with the narrow spray pattern. While this combo seems to give decent performance for most that have done it, it also seems to combine the least desirable traits of each of the port styles. I'd imagine that this combo will all but die out once Joey's LIM is available to the general public.

Combo #5
Has anyone actually done this? I can't see any reason to even try it.

Combo #6
Burrita's (Joey) Hybrid-port seems to fix a number of issues associated with #4. It loses the IMRC's, but with a centrally mounted injector for each oval port, there doesn't seem to be any reason to keep them since the ports are combined together anyway. The only remaining downside to Joey's setup will be the plenum volumes for the SVT UIM. But, I would imagine the convenience factor goes up a ton. We'll all wait and see I'm sure, but I think this will be an excellent alternative to the #4 compromise.

 

[Rara]

As a mental exercise, I do think the ideal max hp setup (NA, and at least loosely based on stock parts) would be the split port heads, with redone chambers to "fix" the squish band (would likely require a lot of dyno and development work to get really good) and the larger 3L valves, split port LIM enlarged and port matched with IMRC's either removed or "optimized", and a heavily modified SVT UIM. I would enlarge the plenums, and replace the snaking inlets from the TB to the plenums with a throttle body for each plenum (look at a Viper intake manifold to understand what I'm talking about)

 

[Redlineracer12]

This might not be directly Intake related, but its useful for debating the different configurations I think.

What does everyone think about 3L vs SVT cams in all these configurations? Does it seem like the SVT cams should be used with the SVT UIM/LIM combo and the 3L cams in the straight Oval Ports? I know those are the common setups because when people are swapping the straight 3L's they don't tear out the cams and when people are building the SVT UIM/LIM they have the SVT cams available usually. So basically which cams would you prefer for each configuration? This is a pretty debated topic on NECO and FCO but I don't think I've seen it here too much....

 

[Rara]

The cam issue can be a little difficult, because there really is no good back to back comparison data available that I am aware of. Sure there are dyno plots of different cars with each, but being in different locations, in different engines, on different dynos means that the absolute numbers have to be taken with a grain of salt and can't be directly compared. What you can do is look at the trends, and decide which setup will better fit your driving style.
The simple fact is that a fixed cam setup is designed to produce peak torque at a single rpm. The 3L cams are designed to produce peak torque at a noticably lower rpm than the SVT cams. This gives the 3L cams a pretty solid low to mid-range punch, but since they peak early for torque, it also means that horsepower suffers some (horsepower is a direct mathematical function of torque and rpm) compared to a cam set that is designed to have its torque peak at a higher rpm, like the SVT (or ST220) cams.
I think that in a 3L w/ SVT cams, where the peak power comes at a higher rpm it would probably be more affected by the small plenum volumes, where with the 3L cams the power would have already started to fall off anyway.
but, in all honesty, the best we can do is make educated guesses at exactly what it will do until someone puts the resources together to do back to back to back engine dyno tests. (I doubt someone would want to change cams in a car on the dyno, lol.)

 

[Bradness]

Plus the SVT were handpicked cranks from the assembly line which makes me feel better about the crank. But I have no sure facts on why besides a race team that has a 3 liter turning up 8k for racing using the same configuration.

Do you know what factors were used to make the decison to pick crank X over crank Y for an SVT? Are all of the 2.5 cranks forged, nitrided, etc.?

Too bad I tossed an SVT crank that had 2 seized con rod bearings. Still got a couple of standard Duratec cranks though. They could be sent out for blueprinting & balancing anyhow.

I see the additonal oiling drainbacks in the 3.0 head are not being discussed. Is there a consensus that this is now a non issue?

 

[Bradness]

There's a 96 SHO in the local wrecking yard and I've noticed that the LIM appears to be an oval configuration, BUT it has an IMRC box. As I understand it, this motor is all 2.5 with 2 extra cylinders tacked on 1 end equalling 3.4 litres of displacement. I believe both plenums were joined at the opposite (to the t-body) end. I tried to buy the UIM/LIM but the owner wanted to sell the complete engine.

Anyone familiar with the guts of this intake setup?

 

[Rara]

Do you know what factors were used to make the decison to pick crank X over crank Y for an SVT? Are all of the 2.5 cranks forged, nitrided, etc.?

Too bad I tossed an SVT crank that had 2 seized con rod bearings. Still got a couple of standard Duratec cranks though. They could be sent out for blueprinting & balancing anyhow.

I see the additonal oiling drainbacks in the 3.0 head are not being discussed. Is there a consensus that this is now a non issue?

First, I'm not convinced there was any actual hand-picking of cranks for the CSVT. If there was, it would have only been within the existing Ford "select-fit" system of mating parts with very tight tolerances at the engine plants.

Second, the oil drains are outside the scope of this discussion, but I did mention them briefly above.

 

[todras]

Well, I've done a full oval port and my next will be the Demon route with ported oval port heads to the 2.5 LIM/UIM. Too many things to mod even though I did complete it. Had to pay Terry to adapt the TB bracket, EGR, fuel rail, etc. Get the Bugsuki intake plate and port those babies!

 

[Pudmunkie]

You loved doing my swap... everything went where it was supposed to.... mostly.

 

[Reebs]

Get the Bugsuki intake plate and port those babies!

That is the route I went as well... 3L block with ported 3L heads (SVT Cams), bugzuki LIM plates [allowed me to NOT have to JB weld the injector valley in the oval port head!], SVT LIM with secondairies, SVT UIM. I am very pleased with the setup and it was pretty easy; the next 3L I drop in sometime in the next few weeks will have the Nautaulis Performance LIM so I will be able to give a better opinion on that. I sure the heck am looking forward to the ease of install with it though. No head porting to deal with!