1971 240z ITB install

[LooseRocks]

Platinum Racing Product out of Australia.  

 

https://platinumracingproductsusa.com/

[Leon]

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.

[DuffyMahoney]

16 hours ago, LooseRocks said:

Platinum Racing Product out of Australia.  

 

https://platinumracingproductsusa.com/

I ordered the one for the JZ motor.  It's 6-1 which I want and also comes the so close to the 95mm between plugs, hopefully it just clicks in! 

[Ben280]

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!

[tioga]

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. 

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 September 7, 2019 by tioga

[tioga]

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. 

[tioga]

Here is my coil bracket. I had a Rf noise problem that took forever to figure our from my LS coils, I made this coil bracket with shielding all the way down to the plug. Immediately fixed the

 

 

[DuffyMahoney]

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 

[DuffyMahoney]

I asked some more questions. 

 

Here is the original email. Maybe IAC can handle the idle and allow me vacuum? 

[tioga]

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 September 7, 2019 by tioga

[tioga]

I have seen that too that’s why I ordered the ports. You put the damn ports in Cap off each one so they are allowing zero air in and the car idles high. Loosen  the throttle stop screws so the throttle plates close al the way down still too high. It makes perfect since if you think about it. Since these nipples only install just a short way in the body you have the air bleeds wide open and they pass a lot of air. 

[tioga]

9 minutes ago, DuffyMahoney said:

I asked some more questions. 

 

Here is the original email. Maybe IAC can handle the idle and allow me vacuum? 

If you look at the body in that diagram it is not the same as my body and from your pic not the same as yours either though it’s hard to tell from your pic. These are the bodies in the pic I told you to look at on the jenvey site with the Ginetta badge. Note the parallel air bleed passage and the extra Allen at the air horn end. Our bodies have a angled passage for the air bleed. Take a close look. 

[tioga]

Since you already have a intake collection like me just add the jenvey to the Harada and Sk you already have. I am inquiring if they can make it in the same black paint as the bodies. 

[DuffyMahoney]

My intake only can do 5 of the 6 runners. So I need to figure it out. 

 

They told me these would work. I will pull mine off tomorrow and look it more. 

 

https://www.universalpowerconversion.com/miniature-male-branch-tee-hose-barb-brass-p-3422.html

[tioga]

This is what I have used for now. I am using with push lock fittings and a stainless pipe connection them looks really clean. I will send a pic tomorrow. The location of the ports on the t-bodies looks even better and gets out of the way of the linkage but these work. 

 

https://www.oer-carburetor.site/product/16

 

shipping from Japan is faster than from California. You can get the heat shield at the same time, it is a very nice heat shield. 

 

https://www.oer-carburetor.site/product-list/18

Edited September 7, 2019 by tioga

[DuffyMahoney]

I am so glad I didn't do the vac log on the ITBs. 

 

So I am going to attempt to re tap my BSPT threads to NPT (I have had great success with it actually) Then use these.

 

https://www.universalpowerconversion.com/miniature-male-branch-tee-hose-barb-brass-p-3356.html

 

https://www.universalpowerconversion.com/miniature-male-branch-tee-hose-barb-brass-p-3368.html

 

So the runners will all have a 1/8 NPT by 1/8 Hose barb T.  That way I can connect to a map sensor and also the FPR.  

 

Then on the runner with 1/4 NPT, I will use the 1/4 NPT by 1/8 hose barb, then tap it for a 1/8 NPT by 3/8 Hose barb (3/8 will go to the brake booster).  Then I have nice braided vacuum hoses to make the balance tube/ vac log.  Should look good and solve all my issues.  

[tioga]

You didn’t ask for my opinion but I am going to give it anyway. Those fittings look crude on a otherwise nice build. 

 

Here is my design. h

[DuffyMahoney]

Your setup looks very nice and well thought out.

 

My idea will look great when I’m done. It will take some effort. I want all braided lines. Even the aluminum tube between the ITBs will have a faux braided line over them. The whole fuel system is braided push lock AN fittings. King of a mix of old and new. 

 

I don’t want push lock fittings. Not my style. 

[DuffyMahoney]

Was the oer 1/8 hose barb? 

[tioga]

I believe 5/32. I can look back at my push lock fitting purchase to confirm. They let enough air in to raise the idle a decent amount. You can also just JB weld the hole in the inlet side of the throttle body throat. You can always drill it back out later. There is a Allen plug where jenvey drilled it to begin with. You can pull out the Allen figure out what size drill and re-drill it just like they did. I turned off the barb on the fittings I bought from jenvey and used push lock on them with carbon fiber tube and it looked great. I will prob end up filling the hole. I am on the fence with buying a new set of 50’s with their intake and redoing the whole thing. I would try to buy the ones made for the extra ports if I went that route.