Porting Heads

[kconnor]

Does anyone have experience with ported heads on a SHO? How much power is a street/strip type port job worth? I have a 60k mile 3.2L motor that I will be installing. While I'm getting the valves freshened up, I'd like to get the ports done also. There's already a lot of port area for an engine of this size and I'm wondering if there much to be gained. If there is can you recommend anyone?

 

[NovaSS]

I researched this a while back. Pretty much everyone agrees on this one.

Unless you are running a giant overbore, stroker crank, ultra high RPM, related valve train and cams the stock ports are great as they are.

Some guys gasket match the intake ports to the runners but I bet ( by it self) this mod will not even show on a dyno or strip run.

The only mod I would suggest is opening the chamber walls to unshroud the valves.

 

[stangeater]

It's like every mod...........Done by itself, there will be little or no noticable difference except in your mind........BUT done in conjunction with other mods ie : ported intake/gasket match, larger Maf/chip, Y-pipe, cams, etc......there will be a nice difference. If you have the engine out, and have the money and time, why not do it?

 

[Kens1992mtxSHO]

If the engine's out and if you're going to be doing the above... why not? I would at least gasket match.

 

[firstgen89sho]

found this on another forum, pretty good reading

http://www.babcox.com/editorial/us/us110128.htm

 

[Slo-Sho]

What would happen in theory if one were to remove the bridge across the intake port? It would seem that the runners would get a better shot at both valves...

 

[NovaSS]

If you remove the bridge you would have to move the merge point back up into the runners.

This would in effect shorten the primary runner and I would assume a loss of low end torque.

The two stage intake runner design is what makes the SHO work, it provides a very wide torque band to get the car moving. Most of the intake mods performed move the power band higher, this may result in a over all performance loss in real world street driving.

 

[illSHOyou]

If you remove the bridge you would have to move the merge point back up into the runners.

This would in effect shorten the primary runner and I would assume a loss of low end torque.

The two stage intake runner design is what makes the SHO work, it provides a very wide torque band to get the car moving. Most of the intake mods performed move the power band higher, this may result in a over all performance loss in real world street driving.

It would shorten the primary and secondary runners. You could go further than that and raise the merge point in the intake manifold. This is some really good stuff were talking about here. Sure low end tq could be changed for the worse, but a stage 2 cam track car, this might be the ticket...?

 

[NovaSS]

The main compromise made of the intake was to fit it under the stock taurus hood. This forced the desiners to flatten out the runners into the bundle of snakes that the production engine uses.

Its my feeling if you plan to go past the 270 -280 Crank HP mark (naturaly aspirated) you need to start from scratch on the intake. Purpose built runners, plenums with no restrictions made for hood clearance.

 

[illSHOyou]

The main compromise made of the intake was to fit it under the stock taurus hood. This forced the desiners to flatten out the runners into the bundle of snakes that the production engine uses.

Its my feeling if you plan to go past the 270 -280 Crank HP mark (naturaly aspirated) you need to start from scratch on the intake. Purpose built runners, plenums with no restrictions made for hood clearance.

I agree. For turbo setups I have heard recently that a dual runner system can improve turbo lag. I wonder if that holds water...?

 

[somedude_001]

1slickred89 made a custom intake on his turbo ATX and he said it made a very noticable improvement in top end performance. he knocked out the divider in the heads and has 2.5" or 2.25" piping to each cylinder.

 

[Eric VerValin]

Fastest "Intake" I seen on a SHO motor, was a Carb!



I'm sure someones got a picture of that Yellow monster around here somewhere..

 

[HotRodKid]

It would shorten the primary and secondary runners.

no it wont, the distance from the plenum to the valve will still be the same

 

[ST 2 SHO]

HotRodKid Quote:
Originally Posted by illSHOyou
It would shorten the primary and secondary runners.

no it wont, the distance from the plenum to the valve will still be the same

ahhhh... the tube length changes IE the runner length in witch the two meet.. not the total length........... AND YES THIS WOULD MAKE A CHANGE better or worse ???? Don't know
I would say by removing them you increase the total volume of the area.... by doing so your going to increase the speed of the air at the valve opening... BUT!!!. your decreasing the air speed from the runner once it enter the large volume area of the head. ( yes I know it all ready does this) BUT .... your increasing this even more by doing it at that point in the head. The total cross volume at the end of the runners need to be very close the the total cross volume at the head inlet port... As long as your decreasing the volume from the start of the two runners two the valve openning I would say it should work well..............this will increase the air speed..... I think..... Can you say flow bench test... only way to see what it does for sure. I'm not a master by any term of the word ...lol JUST MY THOUGHTS
Avery

 

[illSHOyou]

no it wont, the distance from the plenum to the valve will still be the same

Its all how you look at it...I wasn't technically wrong for say, but not specific either..."Then again, I would say I was very wrong, but my point is the tuning is changed."

As ST 2 SHO has mentioned, we would be increasing the cross sectional area at the top of the head. I don't think that will be totally detremental because as the air moves closer to the valves the air is accelerating becuase of the decrease in cross-section area. With the divider at the head deleted and raising the communication area into the runners would effectively raise the power band.

With the new alterations to the head, a shorter primary tube and ultra short secondary tube, the intake tuning would be drastically different. If I were to guess on how the car would behave...The stock secondary opening would be totally incorrect. I would guess a 5,000rpm secondary opening. Most of the engines breathing would be supported by the shorter primary tubes.

If the intake horns are removed your now looking at a maybe 2 inch secondary tube before the head. The motor is going to need some rpm to take advantage of the major changes. I think this motor would beg for a huge cam.

To sum it up, I think you end up just spreading out the intake tunning. Primary tq moves to say 3,500 and secondary tq 5,500-6,000 rpm.

Wether the stock cams work with this major change is the question...

If anything I am sure a turbo would love it.