4-stroke porting

[obr]

Where do you get a goodjob done on a 5 valve head cheap? As for a cheap job unless it is done using flow bench you may not be helping may hurt some air flow especially at low engine speeds. The art of flowing a 5 valver is not as simple as you guys are leading us to believe. As for maxing out your turbo upgrade to a larger and let it all begin again. With meth in as a help to reduce temps the sky is the limit or the weakest link

I think MC-Xpress does it..Not sure where you guys could find it...


Hurricane: I see what you're saying. Thanks for the info... Might have to get one head ported just to see what kind of a difference it makes...Some claim this, some claim that... I don't have the experience with ported turbo-4-strokes to say who is right and who is not...

 

[MOB]

Where do you get a goodjob done on a 5 valve head cheap? As for a cheap job unless it is done using flow bench you may not be helping may hurt some air flow especially at low engine speeds. The art of flowing a 5 valver is not as simple as you guys are leading us to believe. As for maxing out your turbo upgrade to a larger and let it all begin again. With meth in as a help to reduce temps the sky is the limit or the weakest link

I think MC-Xpress does it..Not sure where you guys could find it...

valid points NFS2...not suggesting it is a simple job, exact intent of the thread is to put it out there.

Hurricane: I see what you're saying. Thanks for the info... Might have to get one head ported just to see what kind of a difference it makes...Some claim this, some claim that... I don't have the experience with ported turbo-4-strokes to say who is right and who is not...

Would be curious as to what you find obr...

 

[Ted Jannetty]

It has been described to me....but have never seen it or experienced it. What improvements are to be expected?...let's start with a mild casting cleanup as a baseline, and overshoot from there...

Input for normally asperated and Turbo also welcome...

If you have a head that flows enough air to produce say 300 hp and you increase flow by 10% you can expect a 10% increase in power as long as you take advantage of that flow with the cams.

The cams pretty much maximize the flow capabilities of the head when properly ground and timed.

In a boosted application the same is true and usually shows up as lower boost but more power.

It is all about Pounds of Air Per Minute x 10 + HP.

Turbos are sized by Pounds of Air Per Minute, NOT BOOST.

Boost is a product of restriction and the Cylinder head, cams, header, and turbo, are the restrictors.

Flow equals power, your system is only as good as the smallest hole.

Ted.

 

[mulot30th]

It has been described to me....but have never seen it or experienced it. What improvements are to be expected?...let's start with a mild casting cleanup as a baseline, and overshoot from there...

Input for normally asperated and Turbo also welcome...

If you have a head that flows enough air to produce say 300 hp and you increase flow by 10% you can expect a 10% increase in power as long as you take advantage of that flow with the cams.

The cams pretty much maximize the flow capabilities of the head when properly ground and timed.

In a boosted application the same is true and usually shows up as lower boost but more power.

It is all about Pounds of Air Per Minute x 10 + HP.

Turbos are sized by Pounds of Air Per Minute, NOT BOOST.

Boost is a product of restriction and the Cylinder head, cams, header, and turbo, are the restrictors.

Flow equals power, your system is only as good as the smallest hole.

Ted.

That is well said!!!!!!

 

[Rx1M5]

I had a very brief discussion with Dave (Powderlites) about this one evening when we stopped by and it all started when I asked him how Fundy was getting 165 -170 hp out of the Nytro normally aspirated. The gist of the conversation if I remember was that porting would exchange low end for top end power. I'm not sure I got that eniterly right but that's what I remember anyways. Again if I recall he said it wouldn't take much to screw up the drivability of the stock Nytro. Hopefully he will chime in here at some point. I love the bottom end on the Nytro but the top is a bit weak.

Rx1M5

 

[obr]

so on boosted applications you will se a decrease in boost, and you just adjust the boost back up and produce more hp at the same amount of boost? without running other cams?

But on a N/A machine you would have to get different cams to get any real benefit of the porting?

Is this correct?

 

[Need for Speed 2]

Not quite the stock cams may work well with porting if kept in there preferred parameters , engine speed compression ratio and so on. Looking at the small block chevy for instance cam selections have been hundreds over the years wich one is best, that depends on the variables and its intended use. As for naturally asperatedon pump gas we built a 565 cu in. chev that makes 862 at 6600 rpms. I think we still hold the record on the dyno for that engine. It was built as a street strip package that can shove a 4000lb. 70 monte -carlo down the strip no tubs 10.26 best pass

 

[Ted Jannetty]

so on boosted applications you will se a decrease in boost, and you just adjust the boost back up and produce more hp at the same amount of boost? without running other cams?

But on a N/A machine you would have to get different cams to get any real benefit of the porting?

Is this correct?

You will see a gain in power the side affect is lower boost due to lower restriction across the head, PROVIDING your head is the biggest restriction in the system.

No need to turn up the boost to see the benifit of Porting.

Cams can and will benefit boost applications as well.

On a side Note, if you are cramming more air and fuel in the cylinder, your still raising cylinder pressure to make more power, and the fuel your burning still has limitations for detonation.

I said it before, the fuel is the limiter, the fuel is the limiter, the fuel is the limiter.

Peace

 

[rxrider]

Having a power increase and a charge tube pressure decrease would be a benefit, lower pressure in the charge tube would net lower intake charge temps, good thing

This is a very interesting and informative debate. Keep it coming.

 

[obr]

so on boosted applications you will se a decrease in boost, and you just adjust the boost back up and produce more hp at the same amount of boost? without running other cams?

But on a N/A machine you would have to get different cams to get any real benefit of the porting?

Is this correct?

You will see a gain in power the side affect is lower boost due to lower restriction across the head, PROVIDING your head is the biggest restriction in the system.

No need to turn up the boost to see the benifit of Porting.

Cams can and will benefit boost applications as well.

On a side Note, if you are cramming more air and fuel in the cylinder, your still raising cylinder pressure to make more power, and the fuel your burning still has limitations for detonation.

I said it before, the fuel is the limiter, the fuel is the limiter, the fuel is the limiter.

Peace

With the fuel being the limiter, what happens when you add meth injection? Wiill the fuel STILL be the limiter? Or will the head be the restrictor in the system? How much further can you push the limit with meth before deto?

 

[mrviper700]

efficiency of the turbo exh housing/header will be the factor, the fuel used to be limiting, but the meth injection solves the deto. puzzle.

 

[Ted Jannetty]

With the fuel being the limiter, what happens when you add meth injection? Wiill the fuel STILL be the limiter? Or will the head be the restrictor in the system? How much further can you push the limit with meth before deto?

There are a lot of what if scenarios, What if you set up for Meth injection and your out in the mountains and you run out of Meth, your porked!

You will say, well if I run out of meth I will turn the boost down, then you don't have 400 hp.

So the fuel in the Tank is the limiter of power and Deto Protection.

I am a big advocate of KISS.

Keep it Simple Sir, 400 hp is a rediculous amount of power and I don't think anyone Realizes what 400 hp really is and I don't believe for a minute that anyone acutally has it and can actually use it in any type of trail or mountain riding.

The clutches, Belt, Chassis, Jackshafts, tracks, cannot contain that much power efficiently or put it to use.

Making the power on the Dyno and putting it to work for you are 2 completly different things.

This should stir the pot!

Ted.

 

[mulot30th]

With the fuel being the limiter, what happens when you add meth injection? Wiill the fuel STILL be the limiter? Or will the head be the restrictor in the system? How much further can you push the limit with meth before deto?

There are a lot of what if scenarios, What if you set up for Meth injection and your out in the mountains and you run out of Meth, your porked!

You will say, well if I run out of meth I will turn the boost down, then you don't have 400 hp.

So the fuel in the Tank is the limiter of power and Deto Protection.

I am a big advocate of KISS.

Keep it Simple Sir, 400 hp is a rediculous amount of power and I don't think anyone Realizes what 400 hp really is and I don't believe for a minute that anyone acutally has it and can actually use it in any type of trail or mountain riding.

The clutches, Belt, Chassis, Jackshafts, tracks, cannot contain that much power efficiently or put it to use.

Making the power on the Dyno and putting it to work for you are 2 completly different things.

This should stir the pot!

Ted.

You definitely have a point here!

I tried my tpex as 20psi a couple times at the end of season...

Granted I have not run it very much at this power level.... but as soon as mash the throttle, the sled definitely want to go strait ahead... especially in deep snow....

At 15 psi... is was more driveable... but even then... I had to release throttle somewhat to change direction while climbing.

But... I am no more than average rider.... so more than probably a very good driver could manage 20+psi much better.

 

[Rx1M5]

I know how my sled goes at 250+ HP so I'm thinkin that if you're running 400 you better be pointed exactly where you want to go when you nail it.

Rx1M5

 

[obr]

Jannetty you make som good and valid points...

But. IF you run out of meth? Well, WHAT if you run out of fuel? It's pretty much the same thing? I see where you're going, and I agree with you some....


And...400 hp is probably too much in most situations, but so is 250+...Remember back a few years, who had 200+ hp sleds on the mountain? it's not that much that you will NEED 400 hp, but it the surge more hp.....it's hard being a hp addict, but somebodys gotta 'do' it...

well, this has turned away from porting, I'm sorry....