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What ITB


caen fred

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Aren't those the HKS units you got from Japan?

 

I have a few clarifiying questions, as the HKS ITB's clearly have "HKS" on the piece between the barrels visible looking down on them installed on the engine. They appear to be 40 and not 45mm is this correct? They appear to be frozen at half-throttle? The idle bypass/equalization screws are an interesting touch.

 

Where is the TPS mount, usually the rearmost body has a mounting provision for the TPS. It can be a small flange, or a larger round recessed mount for a different type of TPS (those are what are on the HKS)

 

SK's usually say 'SK' on them as well. I just don't see a TPS mounting provision, possibly making them from a very early analog system.

 

Of course, the 'Nissan' bodies used in 71 for the Rally Cars also clearly had "Nissan" on them, as well as the 'Hitachi Star'...

 

Not the best photos, and took forever to load on my laptop, but popped right up on my iPhone.

Edited by Tony D
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Thank's TonyD, yep those are tho one from Japan. No marking on any of them... I cannot find any definite pict of a HKS ITB from that era on the web. From what I remember, the last HKS I had in my hands had a center spring set-up in between the 2 barrels. This on have a lateral spring (missing on this one) and no depression pickup on the ITB. Peculiear thing :huh:

I will mount the TPS on the last one. They are 44, the Cannon manifold is 40/41 and the Plenum more like 38. As it's on my bench should I port match all to 44 or size down the ITB to 40 :blink: for the P90... the other head was cracked.

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The plenum is sized down for more 'modulator ring' action when used with carbs.

Other than a brand new plenum, I don't think I have EVER seen one in that condition!

 

Porting to match the ITB's is what you want to do, there is nothing to be gained on an ITB with the restriction.

 

Then again...maybe I should trade you 'cause if I ever decided to do a carb setup again, just for retrogoodness and car shows...

What am I SAYING!?!?!?!?!

 

Port it!

 

I can send my photos of my ITB's if you send me detailed photos of yours!

 

(As soon as I get them back from PALLNET, who is currently making fuel rails and vacuum logs for me and 24OZ here... We have identical setups on Mikuni Manifolds.)

Edited by Tony D
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  • 1 month later...

I love the HKS set-up. I'd love to see what it looks like in the engine compartment and of course a nice video of the thing running. Nice thread. What EMS is used with vintage ITBs? I know that today, you could use MegaSquirt for your EMS, but given TonyD's comment on ITBs being older than I would know ... what EMS was used on early ITBs?

Edited by 240zip
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an HKS set up look crammed in ther ;) we run yetterbens old set up in my dads car with a t3/4, next mods are a 350z 6 speed and r200 lsd. Anyhow.. it does nicely fill up the engine bay, and is a bit harder to play with than EFI in my experiance. However it does give the right period feel to it !

Edited by frank280zx
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Nope, it was a first generation Bosch License. JECS Box, looked EXACTLY like the box and loom you would remove from a 68VW Type III.

If you look at some of the Rally Cars in 71-73 you will see on the door "JECS EGI" or something like that---those were the cars equipped with the EFI. Many times used because gas quality was not consistent during the rally stages (like East Africa...) and in the middle of the dashboard under where the heater controls were was a set of four dials that allowed tuning of mixture on the fly! The MAP sensor (no AFC Flow Meter for this system!) was large, like the little cans of Rolling Rock. Same as the VW or for that matter the early DOHC Isuzu Bellets (but the Bellet, being Isuzu was tied in with GM used REAL Bosch stuff on the production cars almost identical to the VW setup... The first generation Bosch was MAP based, the second generation was AFC (Air Flow Control) or Flapper-Door Metering. Subsequent generations simply changed the type of monitoring of airflow (MAF instead of Metering Flap AFM) and added O2 Feedback for some rudimentary fuel trim.

 

If you look at the original SK or HKS Analog Fueling Computers, you will see similar four dials as the original JECS system.

 

And everybody thinks SDS was the first with cockpit dial adjustment of fuel trim! (Not saying Nissan was by any stretch, but they did have this in the cars almost from DAY ONE.)

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