Slowest turbo Miata ever
#423
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I am having a hard time understanding why he would port the floor of the intake runner. I was always taught that you never do that. Not saying that what he did is wrong or that it will not work better, but it is different than what I know.
Were you able to get any before and after flow data?
Were you able to get any before and after flow data?
Because it's the shortest distance into the cylinder, among other things. Why hog out material on the top when air being forced in, or sucked in won't want to go up that way? The exhaust side is opposite. The top of the port was ported out more because of the way exhaust gasses will be flowing up.
I didn't get any flow data because the flow bench he uses doesn't sell the adapter small enough for the bp ports or something.
Either way, it spools quicker and makes more HP than it did before on wastegate.
I didn't get any flow data because the flow bench he uses doesn't sell the adapter small enough for the bp ports or something.
Either way, it spools quicker and makes more HP than it did before on wastegate.
Cutting into the floor causes the airflow to take a more abrupt turn before entering into the valve seat area. The reason the 99+ head works so much better is because the runner has been raised creating a straighter shot.
The fact that the runner is larger and smoother will probably make more power, but it is not likely to be maximized by cutting the floor.
I am not hating, just be mindful of that in the future. If you find that you want to further develop your head, you could epoxy the floor and re-port it. It is what everyone use to do when there were no heads available with raised runners.
The fact that the runner is larger and smoother will probably make more power, but it is not likely to be maximized by cutting the floor.
I am not hating, just be mindful of that in the future. If you find that you want to further develop your head, you could epoxy the floor and re-port it. It is what everyone use to do when there were no heads available with raised runners.
#424
Your logic is based on the fact that it is a shorter distance to one side of the valve. What about the other side? Do you see the abrupt angle the air has to turn to enter the earlier head? You make it worse by cutting the floor.
Changing the valve angle and or raising the port is what creates equal pressure all around the edge of the valve as it enters the cylinder.
It's head porting 101.
Changing the valve angle and or raising the port is what creates equal pressure all around the edge of the valve as it enters the cylinder.
It's head porting 101.
#426
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Well. I posted my dyno numbers, with my **** tune, and the .msq with all my variables.
I don't have any flow bench numbers to put out there. Take it how you will.
I don't have any flow bench numbers to put out there. Take it how you will.
#427
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Yeah, the only place on the bottom of the runner you would want to port is the short side radius on the earlier head. You would do this to make the short side curve less dramatic and a bit straighter. Notice the later head has a much less pronounced short side turn due to superior port angle. There is much less work to be done there on the newer head.
#428
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My engine builder made it in this Magazines top 16 engine builders of 2013.
The 2013 Performance Engine Builder of the Year Contest Reaches
Second one down. Besnik Engine Design, Center Line, MI.
The 2013 Performance Engine Builder of the Year Contest Reaches
Second one down. Besnik Engine Design, Center Line, MI.
#429
My engine builder made it in this Magazines top 16 engine builders of 2013.
The 2013 Performance Engine Builder of the Year Contest Reaches
Second one down. Besnik Engine Design, Center Line, MI.
The 2013 Performance Engine Builder of the Year Contest Reaches
Second one down. Besnik Engine Design, Center Line, MI.
Pretty hard to argue with that. I think the description of the port job you posted on the intake side is somewhat incomplete.
I have spent some time looking at the port pictures since this was brought back up. My guess is he ported the floor at the edge of the runner closest to the intake manifold, and ramped it up to about the stock level at about the middle of the runner to create a slight curve further upstream.
On the roof, my guess the beginning of the runner was kept close to stock right at the intake manifold, and further downstream the roof was ported in order to match the floor profile, and to have a more gradual bend towards the face of the valve.
#430
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I mean, I think he's right about the true, best way to do porting.
However... your numbers are STRONG. It's mostly because of your car/your build that I feel good going with an FM2 no electronics kit for my turbo build this year. (at least for now... hehe)
I loved how your exhaust sounded, how the turbo spooled, and just overall the way the car felt, even if I only felt it from the passenger seat.
Note: this post was written like 3 days ago. Still wanted to share all the same because I love how your car felt and sounded and I want to copy it in a clean NB2.
However... your numbers are STRONG. It's mostly because of your car/your build that I feel good going with an FM2 no electronics kit for my turbo build this year. (at least for now... hehe)
I loved how your exhaust sounded, how the turbo spooled, and just overall the way the car felt, even if I only felt it from the passenger seat.
Note: this post was written like 3 days ago. Still wanted to share all the same because I love how your car felt and sounded and I want to copy it in a clean NB2.
#431
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Diary update.
You don't get very many dry road sunny Sundays in January here in Michigan. So when you do, you have to take advantage of them.
Hooked an old battery up to the NA, put the key in, primed the fuel system, and turned it over. She fired to life immediately first try. Ran on 3 cylinders for about 4 seconds then proceeded to purr away.
Keeping it in a climate control garage i'm sure helped a little.
Couldn't help but take it for a spin. I totally forgot how much of a monster this car is. It is so much different than the NB. To spare you from the boring details, i'll sum it up by saying it's simply more raw.
Not to mention the endless wheelspin and actual power.
Even went ahead and fired up the bike. Like a typical Honda, it did it with no fuss.
I am not going out for a ride, even though, it's sooooo tempting.
You don't get very many dry road sunny Sundays in January here in Michigan. So when you do, you have to take advantage of them.
Hooked an old battery up to the NA, put the key in, primed the fuel system, and turned it over. She fired to life immediately first try. Ran on 3 cylinders for about 4 seconds then proceeded to purr away.
Keeping it in a climate control garage i'm sure helped a little.
Couldn't help but take it for a spin. I totally forgot how much of a monster this car is. It is so much different than the NB. To spare you from the boring details, i'll sum it up by saying it's simply more raw.
Not to mention the endless wheelspin and actual power.
Even went ahead and fired up the bike. Like a typical Honda, it did it with no fuss.
I am not going out for a ride, even though, it's sooooo tempting.
#434
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Nice man. Would you agree with the statement, NB is a better car, NA is a better miata? Or whatever I've always heard people say.
Seems like NB would be the ticket for a DD, but NA for a toy/track car. Just speculation, i only drove a NB once and it was on horrible coils with a cut off exhaust. it felt okay, but my NA with AGX (read:terrible) suspension rode 100x better.
Seems like NB would be the ticket for a DD, but NA for a toy/track car. Just speculation, i only drove a NB once and it was on horrible coils with a cut off exhaust. it felt okay, but my NA with AGX (read:terrible) suspension rode 100x better.
#438
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Edit* NB clutch chatter is REALLLLYYY getting annoying.
Also, it seems like it's getting a random single missfire, perhaps factory spark unit? Oh well, i'll live with it.
NB key is chipped? Ugh, lame...
#440
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I remember being annoyed by both of those things when I switched from my '94 to my '02. If you slip the clutch a little extra it will sometimes fix the chatter for a little while. It will come back, though. I switched to megasquirt and an FM clutch, and then completely forgot about the chatter.