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Clevo120Y

crossflow porting results

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Have say I agree with Sean fully on this. To do this on a small csa means leaving the spark plug out. Years of development is actually just making the holes the size they need to be which is very far from stock or small or ground breaking news.

 Not unexpected as your trying to sell your self and I understand that but please just call it what it is...a cyl head with the right sized holes...big.

I wish you and whoever involved well in the project but please be prepared to be questioned and provide real answers if you want to showcase work and remember its all been done by people before. Holding secrets on something no one here will copy anyway is frivolous.

 

Goodluck Rob

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Bore Size:    3.7in
Stroke:         3.91in

Minimum Port c/s Area = (bore2 x stroke x RPM) ÷ 190,000
Area = (13.96 x 3.9 x 7,500) ÷ 190,000 = 2.14 square inches

so you'd need at least 2.1" of CSA on the head to fully support the motor, simple math really and 2.1" hole is not exactly small unless one can find a way to compress air without a turbine.....so you'd need 55mm ITB's

that's pending you can spin and make power at 7500, if you can't spin it that far then the port will obviously be a lot smaller  but 2" hole is given

 

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I will also say that none of these figures mean a great deal until I can get my car up and running and prove what can be achieved with THORS current head and then the next generation head.  Unfortunately work has been busy for me but I will be out in the car next year and we will see if all this flow equates to a decent number and a reliable engine and fun times with mates. Cause that's what it's all about really. 

Achieving success on the flow bench is one thing, we need to carry this over to the track. In the mean time the tst head will go back for some tweaking to see if we can improve the slight losses in low to mid lift. They are still reasonable, but I believe we can do better. 

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You never know, once the car runs the numbers I might post a pic of the port.  Hell with all this interest and conjecture I might even post a picture of the chamber and the port window. I could always stick some cotton wool or something in the runner to not give away whats going on in there and show the 'port window's. Maybe that might be the go.  

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I don't see the problem of posting about the CSA size, its only one factor of many in the port design, sure you could post its a say 1.9", If I go out to the shed & could port my head to a 1.9" CSA, but doesn't mean I'm going to get anywhere near the same radius on my short turn, bowl & valve guide shape, & the list goes on... At the port entry you could have not taken as much of the base of the port & worked more on raising the port roof, by no means am I going to make the same port as what you have made,

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By no means am I having a go at anyone, or against others work, & happy for you to keep any detailed pictures to your self if wanted.

I made sure when posting pictures of my CNC ported xflow head to not give away any detailed pics of the ports, just a pic of chamber (which I did myself) showing CNC grooved bowls. as specially since they have there own R&D in that port design & its not my own work to show. & wouldn't even have a clue at its CSA...

I don't see posting numerical figures of a port as anything major, as specailly when you freely post flow numbers. but there's no worries here.. I like reading & compering on engines to others, against the build figures & to what they end up producing at the end of the day, to further my knowledge. I'm even very interested to see what power my xflow makes in its current form giving the my cylinder head flows up to 250.8cfm @ .650" & flows 236cfm at peak cam lift as where normally a head flow for a similar engine Ive seen to be around 200-215cfm.  Have a good week, catch ya's another day.

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Just to clear up what broken wheel has said. If  that theory (a big if) he has applied is correct, 2.14 sq inches is a 1.65" (43mm) diameter port not 2".

Sly, do you have pictures of the material that needs to be built back up opposite the inlet valve that you can add to this thread?

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4 minutes ago, CHESTNUTXE said:

i wanna race ya's as well:lol: in my crossy ,friendly heads up,to see how much more i need to do to it lol.

Same same!

Here is mine, pulled it out of storage after about 13 months ... first start don't mind the bottom end knock, she'll be right

 

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hmmmm nope,no exhaust was just gunna run it straight out the extractors if legal at the track im not up to speed on regulations,does it have to be registed ? i was gunna trailer it there.

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Super street up here must run mufflers. Super street up,here goes down to 11.00. But it's an IHRA track and they change the rules every bloody meeting and even halfway through a meeting.  

I'm pretty sure Willowbank runs by the books. Non Andra/ IHRA tracks like heathcote and others let you do what you like really. 

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