Side draft intake mani, size differences?

[Conley]

Hello everyone. I am looking into available manifolds for a pair of side-draft carbs (Mikuni or Weber) to fit an L18. I have a few questions if anyone could please help:

From what I've read, the Mikuni brand manifold is the shortest (to clear the brake master with filters or horns on the carbs) but is also impossible to find. I'm going to keep my eyes and ears open, but in the meantime, does anyone have any hands on experience with dual-carb manifolds from Pierce, Redline, or Cannon?

Question is: How long are these from flange to flange? is any one of these shorter than the others? I could not find dimensions online. A person from Pierce emailed me back and said they sometimes have a shorter manifold available but that it is on backorder and they didn't reply when I asked for a part #.
I tried searching the forum as well (and others) but couldn't find the sizes.

Also it occurred to me that having a fabricator fab up a custom inlet mani with the appropriate flanges might not be too obscenely expensive, so if nothing else I could look into that. Anyone had this done?

Side note: My car doesn't actually have a booster, so maybe the longer manifolds will fit anyways? I thought it would be nice to leave room for a booster someday if I locate one.

Thanks all!!

[Conley]

I heard back from Pierce and they gave me the part number for what they said was the shorter intake manifold, it is mt-0037-c.
It's the one for the 610, 710, 620 and S10 200SX.

He also said its back in stock

[yenpit]

So none of the USA spec 68-73 510's had a booster, but people have installed the B210 booster before. The original 69-73 510 brake master had the bleed screws on the right side of the master, facing the engine. Those are the biggest issue, as they stick out about 1in, thus causing fitment issues with air filters in that already tight space! If you are improving the front brakes and/or installing rear disc brakes, you should consider a different brake master cyl bore AND use a brake master cyl where the bleed screws are on the left side, facing the inner front fender/clutch master. That gets them out of the way! The Wilwood brake master is a popular choice!

Yes, the elusive Mikuni/Datsun Competition intake is the shortest runner, thus leaves more room for bigger air filters. I think the Cannon is the longest runner, thus less room for proper air filters.

[demo243]

I heard back from Pierce and they gave me the part number for what they said was the shorter intake manifold, it is mt-0037-c.
It's the one for the 610, 710, 620 and S10 200SX.

He also said its back in stock

One of the guys over on Ratsun just used that manifold on his 521. I was impressed how short it was. I think the Mikuni one is slightly shorter, but as mentioned they are very hard to find. Keep in mind this photo is a 521- not sure how much if any extra room there is between the engine and the brake master.

https://ratsun.net/topic/72655-just-bou ... nt=1704238

[Conley]

Yenpit, that is fantastic, thank you! Your name is hilarious. I wasn't aware of the bleed screws being on the other side on the wilwood brake master. I was considering a 280ZX strut swap anyways so that may be the ticket.

Demo243, thanks for the pic and the link! Very helpful. Those are very short!

[Three B's Racing]

Those are nice and short fersure!! but don't the two manifold have to be vacuum connected to each other for proper operation? This is what I've always heard plus all dual carb manifolds including SU's are vacuum connected.

[James]

A Z master has the bleeders on the opposite side (7/8" bore)

[Colbino]

The 7/8th z master with 280zx front brakes and drum rears is a perfect setup imo. Had the 15/16th and it was too firm and not enough pedal movement for my liking.

[Tedman]

The HL510/A10/810 13/16" brake master also has the bleeders on the left side. This is my personal favorite for 280zx front brakes with stock rear drums on a 510 sedan.

[Byron510]

Yes, the elusive Mikuni/Datsun Competition intake is the shortest runner, thus leaves more room for bigger air filters. I think the Cannon is the longest runner, thus less room for proper air filters.

Just a small correction here TJ.
The Mikuni manifold is the shortest, but the Datsun Comp manifold is long. Like the ones I cast and machine, they have a 120mm runner length. The length was decided upon after many runs with different length manifolds by John Cadwell on the dyno back in the BRE days. The flattest torque curve was achieved with the longer runner manifold. From a performance point of view, this longer runner length has always been considered the favourite for this.

For packaging, that’s a whole different story. I’ve never measured the Mikuni manifold for exact length. The Mikuni manifold must be about 2/3rds of the length of my manifold.

Just thought I’d interject into this conversation.

Thanks guys.

Byron

[510rob]

Byron, this might be a good time to plug the 90° rotated brake master adapter that was on the drawing board at some point...

[MikeY]

Yes, I'm installing 240z su's on my sons 2.3 this winter. Our preliminary measurements have the air filters he bought pretty close to the master. This would be the simple solution. And I'm a fan of the factory air filter on 38 mm su's. My current project will have these and again a moved master would be nice. On my car the forward resiviour has to be drained and removed to remove the filter cover. So priced right, I could use 3.

[yenpit]

Yes, the elusive Mikuni/Datsun Competition intake is the shortest runner, thus leaves more room for bigger air filters. I think the Cannon is the longest runner, thus less room for proper air filters.

Just a small correction here TJ.
The Mikuni manifold is the shortest, but the Datsun Comp manifold is long. Like the ones I cast and machine, they have a 120mm runner length. The length was decided upon after many runs with different length manifolds by John Cadwell on the dyno back in the BRE days. The flattest torque curve was achieved with the longer runner manifold. From a performance point of view, this longer runner length has always been considered the favourite for this.

For packaging, that’s a whole different story. I’ve never measured the Mikuni manifold for exact length. The Mikuni manifold must be about 2/3rds of the length of my manifold.

Just thought I’d interject into this conversation.

Thanks guys.

Byron

I must be mixing up with the Z car, as the Datsun Comp/Mikuni 6cyl intake manifolds are the short runner!

I have a John Caldwell L20B shortblock, that came from my Pro Rallye buddy that passed. Apparently John was in PA for some years after BRE, Eric was in Columbus OH, so John was his machinist! And oddly, rumor has it he is now somewhere here in southern CO! Thanks Byron!

[yenpit]

Yenpit, that is fantastic, thank you! Your name is hilarious. I wasn't aware of the bleed screws being on the other side on the wilwood brake master. I was considering a 280ZX strut swap anyways so that may be the ticket.

Demo243, thanks for the pic and the link! Very helpful. Those are very short!

Yenpit came from my Honda Civic days, as I funneled mulla into building a couple! Yes, Japanese money pit! It stuck, as I moved into the Datsun world!