Datsun B310 turbo coupe, A15 project

[Atomic]

Next time you go to a book store, grab one of these with you:

 

 

Took some formulas:

 

Fuel flow (cc per minute) (HP x K)/C

 

Where HP= maximum horsepower, K = 4,6 for naturally aspirated engines, or 5.6 for turbo/supercharged engines, and C = number of cylinders

Thus a 180 hp turbo A15 with 4-cylinders requires about 252cc of petrol per minute per cylinder to produce that hp.

Next step is to take a look at what size injector we require to provide that flow of 252cc/min while keeping the duty cycle 80%(in my case)

 

Injector static flow(cc per minute)= (TF x 100)/(N x M)

 

Where TF = theoretical flow, N = number of injectors per cylinder, and M = injector duty cycle

In my case, 1 injector per cylinder and duty cycle of max 80% ----------------------------------------------------(252 x100) / (1 x 80)

 

= 315 cc/min

 

So this formula suggest 315cc injectors for 180hp and the other site showed 315cc for 160hp. That said, I will be more exited to see the results when I get this to the dyno :)

[Eagle_Adam]

love your ingenuity! 

[Cpl620]

Sweet idea.

[Atomic]

love your ingenuity! 

 

 

Sweet idea.

Thanks :)

 

But now when I look at the pictures, it makes me wonder if the fuel rail will fit there  :rofl: We'll see~

[H5WAGON]

 

 

 

 

 

 

 

 

Aluminium right?

Attach it right... here..

From back

Other angle.

 

 

So the big question here is: should I weld it straight to the intake manifold, or make some kind of spacer so it could be removable. (kinda moral question, do you guys hate me if I 'ruin' the good old manifold with this plenum) :confused:  :blush:  

 

 

 

The way your approaching this....I don't think we care if you weld to the manifold.....Do what you need to do...lol

[Farmer Joe]

question to get an idea for another answer... 

 

where are the injectors planned to go? 

 

now im assuming the injectors are going to be on the topside on the intake at the end of the runner, close to the head? 

 

id have to say, with the tube sitting on the intake like that, it looks like its gonna leave a small amount of room for the injectors and fuel rail..

 

its tricky building an intake.. ive almost been in the same boat with my carb KA swap. 

 

im gonna keep tabs on this, see how it turns out!

[Atomic]

question to get an idea for another answer... 

 

where are the injectors planned to go? 

 

now im assuming the injectors are going to be on the topside on the intake at the end of the runner, close to the head? 

 

id have to say, with the tube sitting on the intake like that, it looks like its gonna leave a small amount of room for the injectors and fuel rail..

 

its tricky building an intake.. ive almost been in the same boat with my carb KA swap. 

 

im gonna keep tabs on this, see how it turns out!

 

The injectors are going on the topside close to the head. I'm going to test the fitting with another fuel rail that I have as a spare one. We'll see  B) Till next weekend -->

[ggzilla]

Injectors spraying directly towards the valve are much more effective (power and economy both). That's what Nissan did with L18 efi and with A15 factory efi. The heads are slightly notched to allow a straight shot.

[Atomic]

Injectors that I'm going to order

Bosch 0280150785

Used, but cleaned. Here's a video sample:

https://www.youtube.com/watch?v=m4ZsfQJVtkE

and here is the fuel rail. just need to drill holes for the injectors and ready to go! Woop woop :w00t:

[Atomic]

Found a suitable throttle body:

50mm aftermarket with GM 06594 sensor(€65, cheap as fuck). The only problem is that the mega is coming with bosch adapter kit.. So I need to buy wiring for this unit too. Quick messaging around and the guys who sell the mega are willing to solder new wiring if I send my throttle body there.

[Atomic]

Yup, there is a problem with the fuel rail system. It wont fit. So what I need to do is a plate between the plenum and the manifold. No pics today, my camera battery showed  1%. But I can tell that I managed to get the second front strut to its place and wow... It was gorgeous. Stock height around 30cm and now 20cm off the ground. Now I need to shop some good 16'' with low profile tires so I can lower another 5cm. 15cm off the ground was the limit here in Finland, if I can remember correctly.

[Eagle_Adam]

bummer, sounds like you have a plan tho 

[Farmer Joe]

would something like this work better? 

 

just spit ballin...

 

youd have to cut the stock intake and use just the first part of the runners. pop 2 holes in the plenum, and weld em up? 

 

more room for injectors in a normal config like this..

 

[Atomic]

would something like this work better? 

 

just spit ballin...

 

youd have to cut the stock intake and use just the first part of the runners. pop 2 holes in the plenum, and weld em up? 

 

more room for injectors in a normal config like this..

 

I could do this if I wanted to. I know few companies who sell these horizontal runners. But It costs 200 euros. And if I would cut the old one, I need to re-size the plenum + I'm wondering how the water holes would work then? Because now from the original manifold, the water goes from there straight to the water pump. And if I use the original manifold, I could benefit from using one of the two water ports to cool the turbo. (turbo I use is watercooled) 

 

So yeah, possibilities exists but there are other things to consider. But thank you for your ideas and I'm glad u posted them here, so others can consider this option too :)

[Atomic]

There are 2 kind of side intakes:

 

Without water holes

 

With water holes

[Atomic]

Of course the model with water holes is costing $$$. Double the price of the model without waterholes  

[ggzilla]

This is a factory Datsun A14T twin Hitachi SU-type manifold. It is expensive because Gem charges a lot for everything. Normally they sell for a bit less than twin dcoe manifolds.

With water holes

[Atomic]

This is a factory Datsun A14T twin Hitachi SU-type manifold. It is expensive because Gem charges a lot for everything. Normally they sell for a bit less than twin dcoe manifolds.

Good that someone has more knowledge :) But yeah, they're pretty rare? Or does somebody have these with a reasonable price?

[Atomic]

Ahh, pictures finally! + I think I solved the plenum problem~

Lets see:

Throttle body arrived

Made a little cut to the plenum and started to fit things together. As you can see it's better, but not enough room for the fuel rail

Made this little fitting there. I can easily get the required aluminium from the other half of the extinguisher.

More roomy and more accurate injector angle! Maximum angle should be around 20 degrees

And finally here is a picture that shows the difference between stock and modified strut. 10cm.

Here is the welded support for the coil overs.

[ggzilla]

Yes the A14T manifold is fairly rare, but it is also the smallest factory twin-carb manifold. I've seen several sell for $150 each or less.

[Farmer Joe]

i was thinkin youd just cut that stock intake you have there, and use those runners. theres no point in the plenum, if its all going to the one small inlet for the stock carb still. 

 

it would be easier to just fab and elbow to connect to the stock carb flange and to mount the TB if your going to use the complete stock intake. 

[Atomic]

i was thinkin youd just cut that stock intake you have there, and use those runners. theres no point in the plenum, if its all going to the one small inlet for the stock carb still. 

 

it would be easier to just fab and elbow to connect to the stock carb flange and to mount the TB if your going to use the complete stock intake. 

I got your picture. :thumbup: But the problem is that I need those water holes inside the manifold as they share the whole area through the manifold and get sucked in the waterpump + with original manifold I can use one outgoing water pipe for cooling my turbo.

 

Well if the throttle body's surface area is 19,62cm^2 and the current intake manifold ellipse's surface area is 14.92cm^2 (which I'm going to grind more), as long as they have the same surface area, in theory there should be no air losses or pressure drops when under boost. + I think that now the plenum is distributing the 'same' amount of air under the boost to all of the cylinders compared to individual runners. ( now it's 1-2-2[Current plan] instead of 1-4[individual runners] ) With individual runners you need to be more precise with each cylinder configuration as the last runner sucks air in, some other runner is getting less. This is what I read~ Blame 'the book'  :rofl:

[Atomic]

And if this doesn't work, then I can make another plenum and manifold etc. The final data is on the dyno sheet, and there I can see where I'm losing power etc. +50 mm throttle body was little more than I really need, I wanted a little bit bigger if I get more eager on power plan. Suggested throttle bore diameter was balancing between 45-50mm 45 is more into 160 hp and 50 is more like 180-220hp. As long as the throttle body's airflow doesn't go over 300cfm (as calculating how much engine needs at most) it will be okay to use single plate throttle body. But over 300cfm it is advice to use progressive 2-plate throttle body for lower idle and smoother running on small speeds.  

[Atomic]

Intake manifold is now ported larger, approx 23cm^2 hole. I got the package from around the world, injectors are here, front window seal, engine rubber mounts, full front suspension bushing kit. Still waiting for the fuel rail. I ordered 30cm long fuel rail, should be enough. And on Monday I will buy some paint for brake calibers and I'll be looking for some AISI 304 stainless steel tubes for exhaust manifold.

 

Plans to do now on holiday:

 

1. Drill holes to fuel rail

2. Drill holes to intake manifold

3. Attach plenum to the intake manifold

4. Make exhaust manifold + order custom flanges

5. Complete the other front strut

6. Paint brake calibers

7. Test fit engine and manifolds

[Atomic]

Hope you guys are having a nice holiday, here are some pictures:

 

Got another strut ready.

Fresh start.