4-stroke porting

[Need for Speed 2]

Thepower is addictive, and for each person the level of power you can useor handle depends on you. For instance I am sure a guy like say Mike Irmen may handle that 400 ponies better than say just for instance Mulot no finger pointing Mulot but I did see a clip of you Ha Ha dont mean to offend here lets keep it lite. So as for thew power being added traction skill levels so on. But I think for the sled heads and guys that have gas and oil in the veins it is a constant quest for more. I run meth and I love it. I feel safe at the levels I run and I monitor the consumption closely. Last year up in Quebec on a long haul We stopped our group for fuel I pulled the side cover off my nytro filled my jug with windsheild washer fluid then gased up. The guys in the station were having fits trying to figure it out. I dont speak french and they no english it was funny at the least. Also note the meth can be run in as extra fuel supply as well not just deto control. I think there is great potential in this to come as more and more demand more and more products will come . Trail riding my nytro with the group I can go 2 tanks of fuel to 2.5 litres of meth. If I am cranking hard on boost 1 tank to 1 tank. Engine was apart looked good. There is one concern I have on this that the fluid is very corrosive and the intercooler I am sure will eventually become a wall ornament from this process. As for to much 860 horse on the street I am told is insane but I would like to see some n2o added now, so I guess its insane but we all do it to a point. Some more than others,.

 

[MOB]

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

LOL...no worries, it's all in context with efficiency and power...good data.

It's good to put physics into practice in 'the lab'.... ...good discussions...

 

[rxrider]

Found some interesting info on http://www.dgmotors.biz/cylinderhead.htm

Here's a few lines from the page.

Porting:

Cylinder head porting is a way to dramatically improve the performance of your heads. Even if it isn’t high lift numbers you are looking for smoothing out the air flow can increase the air velocity and make dramatic improvements to low-end torque. Of course for big horsepower numbers high lift numbers are important and the only way to get there is with a competent porting job.

Always remember, a good porting job will help and a bad porting job will hurt! Done wrong you can drop airflow and really mess up the combustion chamber design.

Cut and paste

 

[Ted Jannetty]

To sum things up here PORTING DOES WORK when done properly regarless of N/A or Boosted.

But remember your system is only as good as the smallest hole.

Being a race engine builder since 1982 I can without a doubt vouch for proper porting.

FYI, I have a fully ported head sitting on my shelf ready, for my mod motor

Once I Smash my Previous best Stock engine ET and MPH, I will install it.

I want to be the first in the 4's with a stock engine and OEM chassis, and I am knocking on the Door at an unoffical 5.05 et 138.6 mph in 660 ft.

Ted.

 

[Need for Speed 2]

What h.p. #s do you have on that set up Ted Did you dyno it or take an educated guess please.

 

[Need for Speed 2]

Something just came to mind . Years ago we circle raced an open wheeled car back in95 I think any how we had very strict engine rules and they enforced them ferociously. We found through searching 18 different stock cylinder head sets one that out flowed all the rest by miles. Untouched they were better than any of the mildly ported heads we had been cheating with. So in short I wonder if Yamaha castings are so perfectly matched from start of casting run to present day or could there be some preferred casting right from the go. Just one other note We dynoed an engine that had been in the car when we bought it. To our surprise the #s were way low considering what it should have been. Thanks to our dyno guy really quickly he managed to find that the valve train and related components was sendind an intewrfering resonance back through the intake track and messing the carburation up terribly. We boltewd on a new carb and within minutes found 55 h.p. just some food for thought guys

 

[Ted Jannetty]

What h.p. #s do you have on that set up Ted Did you dyno it or take an educated guess please.

Educated guess maybe 350 hp at 22 psi.

Still Can't use all the power I HAVE, I need to go to a 144 suspension so I can lean on it more in the 60 ft. clocks.

Right now, it is SO on the edge, one run it will wheelie and the next it stays down, it is too unpredictable with the 136, and I can't use the 2 step at all.

Making the power was never a problem, using the power efficiently to accelerate the sled from A to B is always the challange

Ted.

 

[MOB]

WRT head castings, and to diverge a bit, I was recently informed that Yamaha's spec for 'acceptable flatness' on the head gasket mating surfaces leave a bit to be desired for boosted apps...contributing to the head gasket issues we're familiar with....better gaskets would help also - some work is being done on that right now in the aftermarket. Depending on 'flatness', decking the mating surfaces would help quite a bit also.

Yamaha castings are not what I would refer to as 'precise', I have not seen what the stock head casting looks like but if they are at all rough in the flow portions it seems to me some simple cleanup/smoothing would measurably improve flow/heat/etc...all toward efficiency.

Any experience/comment in that regard?

Also, what is the process for tuning in meth/water injection? How do you find the area between 'not enough and too much'...?

 

[Ted Jannetty]

Something just came to mind . Years ago we circle raced an open wheeled car back in95 I think any how we had very strict engine rules and they enforced them ferociously. We found through searching 18 different stock cylinder head sets one that out flowed all the rest by miles. Untouched they were better than any of the mildly ported heads we had been cheating with. So in short I wonder if Yamaha castings are so perfectly matched from start of casting run to present day or could there be some preferred casting right from the go. Just one other note We dynoed an engine that had been in the car when we bought it. To our surprise the #s were way low considering what it should have been. Thanks to our dyno guy really quickly he managed to find that the valve train and related components was sendind an intewrfering resonance back through the intake track and messing the carburation up terribly. We boltewd on a new carb and within minutes found 55 h.p. just some food for thought guys

That is very common with sand cast iron heads, they are all over the place, GM uses several foundrys for casting heads and were not real fussy in those days.

These Yamaha engines are lightyears ahead of that stuff, the consistency from motor to motor is incredible.

 

[Ted Jannetty]

Also, what is the process for tuning in meth/water injection? How do you find the area between 'not enough and too much'...?

Typically I will tune to say 12.5:1 without then let it go to 11.5:1 with.

 

[MOB]

Also, what is the process for tuning in meth/water injection? How do you find the area between 'not enough and too much'...?

Typically I will tune to say 12.5:1 without then let it go to 11.5:1 with.

How do you determine at what boost levels to spray?...I wouldn't think it would be continuous...though it may be on the strip.

 

[Need for Speed 2]

Ted you probably are getting to the limits of traction verses weight multiplied by torque and horsepower . Wonder where the limit is . That in itself is a very intriguing acheivement. I am in no way stroking your ego Ted but I think I have just realized where your at with this . You are definitely acheiving what is a very hard to do. Weight is your biggest down fall adding traction will also add rolling resistance ,hmmm very interesting. As for meth injection I load up till it stumbles or acts rich then back it down a bit read plugs and so far it has been one of the easiest learning curves for me . Knock on wood, hope I didnt jinx myself.

 

[Ted Jannetty]

Ted you probably are getting to the limits of traction verses weight multiplied by torque and horsepower . Wonder where the limit is . That in itself is a very intriguing acheivement. I am in no way stroking your ego Ted but I think I have just realized where your at with this . You are definitely acheiving what is a very hard to do. Weight is your biggest down fall adding traction will also add rolling resistance ,hmmm very interesting. As for meth injection I load up till it stumbles or acts rich then back it down a bit read plugs and so far it has been one of the easiest learning curves for me . Knock on wood, hope I didnt jinx myself.

Traction has never been a problem, at 726 lbs. planting the studs has been easy.

We leave off Idle and depending on how fast and hard the power comes on some times it will stand up and some times it will stay down, this is all affected by Atmospheric conditions, engine temp, EGT, A/F, Timing, and such.

Then managing all that power with the clutching is a whole nother feat in itself.

With the 144 I am confident I will be able to launch with say 2-4 psi boost which is a double edged sword, not only does it add a significant amount of clutch engagement power, it also climbs to full power 100 times faster.

This is where I intend to improve my 60 ft times from 1.21 to 1.10 which is worth about 2 tenths in 660 ft, so 4.80s are with in reach.

Ted.

 

[MEAT]

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

The way I see it ( correct me if I am wrong ) the 4 stroke wouldn't loose bottom end by porting alone until you change cam profile and timing to which need to do to get the most out of your porting and to achive 170 hp which would then ruin driveability.Kinda like f-3 porting on a full mod 94 ZR 700 that couldn't catch a 95 EFI ZR580 on UFA purple. Something to be said for a wide powerband.

 

[Turbor]

you can easely loose bottom end with a bad port job, its all about velocity, alot of guys try to get good gains at high valve lift, but loose alot in the lower lift range, thats the challenge gain as mutch in the highest part of the lift and not loose anything in the lower part or even gain down there also. we used to do our own heads on my racecar and had a superflow flowbench, we spent alot of time on it and scraped a couple of heads in the process lol