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DuffyMahoney

1971 240z ITB install

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Working on my 280zxt Cas signal, so I can do full sequential.  

 

I got a very nice 280zxt distributor without a cas from a fellow Datsun nerd.  I then found a basically new fully Nissan Cas from a 1998 Nissan Quest.  Which has the correct trigger wheel.  Pretty neat.  

Dizzy is getting vapor blasted today and I should have it all installed by the weekend.  Pretty excited! 

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Posted (edited)

I also got my haltech in. I opted for the non terminated ended one. It’s has a very fancy fuse panel, relay board and it’s nice small package. 

 

I am taking my kick panel and having it copied in aluminum. Then powder coated (wrinkle or semi gloss?), I will use it to mount my ecu, tach signal converter and the fuse panel. 

 


 

 

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Edited by DuffyMahoney

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On 8/31/2019 at 6:41 AM, DuffyMahoney said:

I got my Jenvy throttles in from Datsun Spirit. 

 

I found out they each have a 6mm vacuum port on top! . I will use these for map, FPR and maybe IAC. 

Those look great! 

 

For getting good MAP signal, be sure to run all the lines together into some sort of manifold. ITB's are annoying to tune already, having weak MAP signal will make it 10x worse, particularly at low end where presumable the ECU is going to actually attempt to reference MAP.

 

Not sure that you need vac signal to your FPR, most EFI installs want constant pressure. Personally, I would put the IAC sensor on a bracket near the intake horns. Something about trying to get a temp signal from vacuum seems off to me.

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Air temp will be right next to the velocity stacks.  Most likely off a stack bolt.  

 

I will do a small map LOG just off the throttle bodies.  The jenvy has a nice 6mm vac port on them.  I haven't decided on IAC or not yet.  But the same vac port would work for it.  

 

 

Edited by DuffyMahoney

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11 hours ago, Ben280 said:

Not sure that you need vac signal to your FPR, most EFI installs want constant pressure.

 

What makes you say that? An FPR without vacuum reference will lead to a wonky fueling table at the very least. It's good practice to maintain a constant pressure difference between the fuel rail and intake manifold, it helps take a variable out of the fueling calculation.

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15 hours ago, Leon said:

 

What makes you say that? An FPR without vacuum reference will lead to a wonky fueling table at the very least. It's good practice to maintain a constant pressure difference between the fuel rail and intake manifold, it helps take a variable out of the fueling calculation.

 

On a street driven car traditional plenum style intake sure! Referencing engine vacuum is useful while the car is at idle to improve fuel economy and maybe a LITTLE drivability, and in a boosted configuration it's essential to a safe motor. In my particular case, (NA, spends a lot of time at WOT) I would rather provide the ECU with a good MAP signal, and use the VE tables in the computer to control fueling. I think particularly with ITB's they develop such poor vacuum at really anything above 30% throttle, having the FPR reference anything is diminishing returns. For me, it's one more thing that can break, so I ignore it. 

 

I'm not a tuning wizard, but I've been running my fuel setup like this for 6+ years and have made pretty good power so far! 

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49 minutes ago, Ben280 said:

 

On a street driven car traditional plenum style intake sure! Referencing engine vacuum is useful while the car is at idle to improve fuel economy and maybe a LITTLE drivability, and in a boosted configuration it's essential to a safe motor. In my particular case, (NA, spends a lot of time at WOT) I would rather provide the ECU with a good MAP signal, and use the VE tables in the computer to control fueling. I think particularly with ITB's they develop such poor vacuum at really anything above 30% throttle, having the FPR reference anything is diminishing returns. For me, it's one more thing that can break, so I ignore it. 

 

I'm not a tuning wizard, but I've been running my fuel setup like this for 6+ years and have made pretty good power so far! 

 

I'm not saying that it wouldn't work, just that it's not good practice. I understand that your case is a particular one being it's a race car. ;)

 

The problem is that no matter how good your MAP signal is, not having a manifold reference for the FPR means that your VE table will be delivering differing amounts of fuel even if the VE table values are equal. Not having the reference makes tuning more difficult and reduces your resolution in high-vacuum areas of the VE table. Of course it can be done, as you have.

 

I just disagree with your premise that "most EFI installs want constant pressure". Most EFI installs definitely have MAP-referenced FPRs for the reasons above, especially for street-driven cars as is the case for the OP. I'm including OEMs here as well, doesn't matter whether they're ITB or not.

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15 hours ago, Leon said:

 

I'm not saying that it wouldn't work, just that it's not good practice. I understand that your case is a particular one being it's a race car. ;)

 

The problem is that no matter how good your MAP signal is, not having a manifold reference for the FPR means that your VE table will be delivering differing amounts of fuel even if the VE table values are equal. Not having the reference makes tuning more difficult and reduces your resolution in high-vacuum areas of the VE table. Of course it can be done, as you have.

 

I just disagree with your premise that "most EFI installs want constant pressure". Most EFI installs definitely have MAP-referenced FPRs for the reasons above, especially for street-driven cars as is the case for the OP. I'm including OEMs here as well, doesn't matter whether they're ITB or not.

 

Fair! My motor rarely lives in a high vacuum area of the VE table, I guess I am/was assuming OP's motor will be in a similar state, which isn't a good position. In my initial post I think I was hung up on the idea of a rising rate FPR in terms of boost, and was confused why OP would want that on a NA car. (I also mis-read IAC as IAT, soooo maybe I should have my reading comprehension skills checked lol!) 

 

Thanks for clarifying and adding some facts!

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On 8/31/2019 at 9:41 AM, DuffyMahoney said:

I got my Jenvy throttles in from Datsun Spirit. 

 

I found out they each have a 6mm vacuum port on top! . I will use these for map, FPR and maybe IAC. 

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Those ports cannot be used unless you block the passage to the air horn side of the t-body. They are intended for balancing within the body. (Bringing up the throat that lags behind if you have one.) Thus there is a passage from one side of the butterfly to the other. When you pull out the adjust screws and put In the nipples they sell at jenvey you open this passage completely and even with completely closed throttle plates it will idle too high. The bodies on their site that have these nipples in them have a different design casting with a Allen plug at the air horn side of the passage as well. I suspect you can use this to block the passage. I am currently discussing this with them and they seem in the dark about this.  You could epoxy the air horn side of the passage. I am considering this but hate too. In reality they are very well balanced butterflies by them selves. I only have one of the adjusters cracked open to balance right now and it was only very slightly off. 

 

If you look here and scroll down the bottom. The black dcoe body that says Ginetta on it has the ports installed and you can see what I mean. 

https://www.jenvey.co.uk/products/#oem-solutions.

 

Jenvey’s intake has ports in line on the bottom hidden from sight. Oer also sells a phenolic spacer with a nipple on each port. 

Edited by tioga

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10 hours ago, Ben280 said:

 

Fair! My motor rarely lives in a high vacuum area of the VE table, I guess I am/was assuming OP's motor will be in a similar state, which isn't a good position. In my initial post I think I was hung up on the idea of a rising rate FPR in terms of boost, and was confused why OP would want that on a NA car. (I also mis-read IAC as IAT, soooo maybe I should have my reading comprehension skills checked lol!) 

 

Thanks for clarifying and adding some facts!

I am not running a manifold reference for the fuel pressure regulator but with a map sensor and FUEL pressure sensor my ecu calculates relative fuel pressure from that info. This is what the modern production fuel systems are doing and is more accurate than the referenced fuel pressure regulator. 

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27 minutes ago, tioga said:

Those ports cannot be used unless you block the passage to the air horn side of the t-body. They are intended for balancing within the body. (Bringing up the throat that lags behind if you have one.) Thus there is a passage from one side of the butterfly to the other. When you pull out the adjust screws and put In the nipples they sell at jenvey you open this passage completely and even with completely closed throttle plates it will idle too high. The bodies on their site that have these nipples in them have a different design casting with a Allen plug at the air horn side of the passage as well. I suspect you can use this to block the passage. I am currently discussing this with them and they seem in the dark about this.  You could epoxy the air horn side of the passage. I am considering this but hate too. In reality they are very well balanced butterflies by them selves. I only have one of the adjusters cracked open to balance right now and it was only very slightly off. 

 

If you look here and scroll down the bottom. The black dcoe body that says Ginetta on it has the ports installed and you can see what I mean. 

https://www.jenvey.co.uk/products/#oem-solutions.

 

Jenvey’s intake has ports in line on the bottom hidden from sight. Oer also sells a phenolic spacer with a nipple on each port. 

Man that sucks. 

 

Jenvy is the one that said to use it for a vacuum port. I will find the email 

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I can send you about 10 emails back and fourth over the last few weeks trying to get the guy on the other end to understand the problem. He kept telling me I can balance with the butterflies! I finally had to yell at him and tell him I am not asking how to balance with the nipples in. I am a 50yr old shop owning mechanic and have had these t-bodies running for over 4 years. Go ask your engineer how to block the air from the air horn side of the butterfly. He apologized and said he would send it to engineering. I assumed when I ordered them they would block that passage and hoped they would seat the same way as the adjuster screw only with a hole down the middle. This design would allow you to cap off the ports, balance the bodies and then when open allow you to add a idle kicker for cold start. 

 

I will say that a timing map with about 25* of advance at 500rpm and 10*  at target idle (800 rpm in my case)  5* at 1k RPM. produce a great timing based constant idle system that is what I have been using for years and idles well on cold start. You can also tell I’d you idle air is set right by just looking at the timing the ecu is running at idle. If it’s running at 15-20* you need to open the plates a bit 

Edited by tioga

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