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Recon1342
Recon1342 Dork
2/10/22 3:45 p.m.
Flynlow (FS) said:

Just checking in as another Cappuccino owner to say I love the work you're doing.  One of the upgrades I had been looking for was an "N1" ECU, supposedly sold over the counter from Suzuki in Japan, now long out of production and occasionally available on yahoo JP auctions.  Seeing a modern PNP option is great!  I will be very curious to see what power levels you see, and where the bottlenecks in the system are. 

I drove mine from Phoenix, AZ back to the east coast right after purchase back in 2017 (with a stop for the Pikes Peak hillclimb).  Hope you don't mind me photo bombing your thread, I can take them down if needed:

 

I always forget how small these are, and then I see one parked next to a Tahoe and remember...

DarkMonohue
DarkMonohue Reader
2/10/22 3:54 p.m.
burdickjp said:

1.65 mm wall thickness.

Sure, 16ga. Pretty much standard issue stuff for your corner muffler shop.

Are you actually special ordering metric tubing, or just using off-the-shelf imperial stuff and describing it in metric units to keep us on our toes?

Flynlow (FS)
Flynlow (FS) Dork
2/10/22 8:01 p.m.
Recon1342 said:

I always forget how small these are, and then I see one parked next to a Tahoe and remember...

It's about 50:50 me parking next to a big truck because I think it's funny, and parking in an empty space only to come out to a lifted F250 next to me because THEY think it's funny :).

Very, very small:

burdickjp
burdickjp Reader
2/11/22 9:30 p.m.

burdickjp
burdickjp Reader
2/26/22 7:36 p.m.

Some progress on my downpipe. I'm getting close to done with this one, which is good, because the car needs to go back on its wheels soon, so I can move on to other things.

DarkMonohue
DarkMonohue Reader
2/26/22 7:54 p.m.

That looks like it'll work just great. Check it for pinholes and run it.

tperkins
tperkins New Reader
3/1/22 3:22 p.m.

Love these little units, I was looking at getting one until I sat in it, unfortunately. 



Don't know how Benny from BCW sits in them lol. 

burdickjp
burdickjp Reader
3/2/22 10:53 a.m.

In reply to tperkins :

Go sit in a Honda Beat. They're probably the biggest inside of the Kei Sports.

With me in this car, I've installed an aftermarket seat and pushed it as far inboard as possible. I, somehow, sit lower in the Cappuccino than in an NA miata. Not sure how, right now.

burdickjp
burdickjp Reader
3/2/22 11:08 a.m.

Here's what I came up with for measuring the camshaft profile. Since the cams are captive in those boxes, there's no real way to get to them from the top side. Also, the lash adjusters leak down over time, so I printed a solid lash adjuster.

 

I clamped everything together on my bench top and put an indicator on the valve face. A large diameter indicator tip, made from a 4A-GE 20V lifter bucket and used for measuring straight off the camshaft on those cams, makes sure that my indicator is square with the valve.

 

Then it's degree wheel and indicator work. All the way around. Go around twice to make sure it's right. Maybe a third time for sanity-check. Round and round we go.

 

I've got a little technical reference book for this car from Japan. It has this little figure showing valve events. If my measurements on the intake side are right, these are at 0.1 mm of lift. I think I've seen that with other cams out of Japan, so I think my measurements are sane and match up. This also means that once I've got the exhaust side measured up, I can drop them into a graph with timing on correctly. And start into my calculators. It's been a long time since I've done that.

burdickjp
burdickjp Reader
3/4/22 12:01 p.m.

I am a bit surprised to see both valve lift profiles are asymetric in the same way, with a nice closing profile.

burdickjp
burdickjp Reader
3/6/22 2:24 p.m.

DarkMonohue
DarkMonohue HalfDork
3/6/22 2:30 p.m.

Very interesting.  Flow just peaks at 6mm.  Not that your valve lift should stop there, mind you.

Dr. Steinhart to the operating room. Dr. Steinhart to the operating room, please...

 

burdickjp
burdickjp Reader
3/6/22 3:14 p.m.
DarkMonohue said:

Very interesting.  Flow just peaks at 6mm.  Not that your valve lift should stop there, mind you.

Dr. Steinhart to the operating room. Dr. Steinhart to the operating room, please...

 

I'm 3d printing some valves of OEM geometry with a back cut to see how that improves the situation. Then I'll be testing with a larger cylinder bore, as these valves are pushed way out to the edge and I'm going to be running a substantially increased bore diameter of 68 mm instead of 65 mm. Then cut some improved valve seats, as the OEM valve seat is just the 45 and a top cut. Testing again at OEM cylinder diameter and 68 mm cylinder diameter. Then some chamber work to deshroud for the new bore diameter. Then port work.

Recon1342
Recon1342 Dork
3/6/22 6:38 p.m.

In reply to burdickjp :

This is the kind of voodoo black magic that I come to GRM for. Flowing a cylinder head is kinda like tuning multiple carburetors. You can make huge gains, or you can totally ruin the powerband.

burdickjp
burdickjp Reader
3/6/22 9:37 p.m.
Recon1342 said:

In reply to burdickjp :

This is the kind of voodoo black magic that I come to GRM for. Flowing a cylinder head is kinda like tuning multiple carburetors. You can make huge gains, or you can totally ruin the powerband.

This head has some low hanging fruit: valves in desperate need of back cuts, seats with only 2 angles, some throat work.

Then there are the less straight forward areas: some chamber de-shrouding and reshaping for the larger bore, some port reshaping we've talked about with the port molds above.

burdickjp
burdickjp Reader
3/7/22 8:47 p.m.

I'm 3D printing valves for flowbench testing of different geometry.

 

oldeskewltoy
oldeskewltoy UberDork
3/8/22 3:57 p.m.

hmmm....  3D valve design does seem like an easy method go test valve shapes - tulip, nailhead. or some blending of the two.  

 

Have you a chosen throat dimension for the bowls/seats to test your valves??

burdickjp
burdickjp Reader
3/8/22 10:51 p.m.
oldeskewltoy said:

Have you a chosen throat dimension for the bowls/seats to test your valves??

This initial testing is to evaluate modifications to the OEM valve without touching the port, then seat geometry, then port. If I have time and effort I will be looking into big seats and big valves.

The OEM intake valve is 24.6 mm in diameter. The OEM exhaust is 21.4 mm. The throats are about 83% of the valve diameter. I'm leaving them there for this initial testing.

After that, I'll probably progressively open them up to 88-90% so that they'll be above 85% for big valves as well.

oldeskewltoy
oldeskewltoy UberDork
3/9/22 11:55 a.m.
burdickjp said:
oldeskewltoy said:

Have you a chosen throat dimension for the bowls/seats to test your valves??

This initial testing is to evaluate modifications to the OEM valve without touching the port, then seat geometry, then port. If I have time and effort I will be looking into big seats and big valves.

The OEM intake valve is 24.6 mm in diameter. The OEM exhaust is 21.4 mm. The throats are about 83% of the valve diameter. I'm leaving them there for this initial testing.

After that, I'll probably progressively open them up to 88-90% so that they'll be above 85% for big valves as well.

Each port(bowl/seat) dimensional change may use a different shape valve, or valve job.   Can I assume with each change (porting w/existing seats, or porting with big seats) you plan on 3D printing the valves and testing. 

 

It just seems backwards to me to design the valve before you have a final (or near final) port shape/size.

burdickjp
burdickjp Reader
3/9/22 2:07 p.m.
oldeskewltoy said:
burdickjp said:
oldeskewltoy said:

Have you a chosen throat dimension for the bowls/seats to test your valves??

This initial testing is to evaluate modifications to the OEM valve without touching the port, then seat geometry, then port. If I have time and effort I will be looking into big seats and big valves.

The OEM intake valve is 24.6 mm in diameter. The OEM exhaust is 21.4 mm. The throats are about 83% of the valve diameter. I'm leaving them there for this initial testing.

After that, I'll probably progressively open them up to 88-90% so that they'll be above 85% for big valves as well.

Each port(bowl/seat) dimensional change may use a different shape valve, or valve job.   Can I assume with each change (porting w/existing seats, or porting with big seats) you plan on 3D printing the valves and testing. 

 

It just seems backwards to me to design the valve before you have a final (or near final) port shape/size.

Blanks in this size range are very limited, so there's not a lot of geometry options to choose from.

The OEM valve and seat are also not very good, so showing small geometry changes, such as back cuts and some more appropriate seat geometry is interesting to me.

burdickjp
burdickjp Reader
3/9/22 2:10 p.m.

This is the intake side. On the left is a 19 mm sphere. It's sitting against the valve guide. On the right is a 20 mm sphere. It is below the seat geometry, but is not all the way down to the valve guide.

I'm playing with these different sized spheres as an exercise to illustrate to myself different cross sections inside the port.

oldeskewltoy
oldeskewltoy UberDork
3/9/22 4:08 p.m.
burdickjp said:

Blanks in this size range are very limited, so there's not a lot of geometry options to choose from.

The OEM valve and seat are also not very good, so showing small geometry changes, such as back cuts and some more appropriate seat geometry is interesting to me.

yes 

This is the intake side. On the left is a 19 mm sphere. It's sitting against the valve guide. On the right is a 20 mm sphere. It is below the seat geometry, but is not all the way down to the valve guide.

I'm playing with these different sized spheres as an exercise to illustrate to myself different cross sections inside the port.

 

 

Fowler has an inexpensive digital ID caliper that I find is effective, I'd added graduations to allow me to be more consistant

 

 

burdickjp
burdickjp Reader
3/9/22 9:09 p.m.
oldeskewltoy said:

Fowler has an inexpensive digital ID caliper that I find is effective, I'd added graduations to allow me to be more consistant

 

millimeter/inch/fahrenheit?

oldeskewltoy
oldeskewltoy UberDork
3/10/22 12:26 p.m.
burdickjp said:
 

millimeter/inch/fahrenheit?

Fractional

burdickjp
burdickjp Reader
3/10/22 3:30 p.m.
oldeskewltoy said:

Fractional

Oh, that's somehow worse.

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