EFI for U20?

[GoldHawg]

What is the latest on EFI setups that could work with the U20 or R16 stroker? I have a friend that just bought a SPL w/U20 5 speed swap and wondering about the easiest route to get EFI. Not concerned so much about absolute power, just want the excellent driveability of EFI.

[redroadster]

I say a harley davidson efi system would be a good match with a main elect pump using the throttle body type
The crank sensor is a bit of a roadblock , really needs a newstyle alt too, just easier and simpler to do tge sr20 etc in the long run
Also VW s CIS was easy to adapt if you have room for a small microwave oven under the hood .
Im just saying you could , not should

[Daryl Smith]

Many aftermarket programmable systems will do the job.
Easiest would be to just control fuel only, using the ignition system to trigger a batch fire system. I've considered putting fuel injector bungs close to the head in an SU manifold. Don't think the SU's would make the best 'throttle bodies' and never progressed further on that idea. There are aftermarket replacements if you want to spend the money....
I started with an early, very simple, MegaSquirt system. Most are much more complicated now.
Not sure how far along they are with the self tuning features, but, pretty sure that is still just fuel only with reportedly mixed results, depending on who you talk to.
Don't underestimate the cost/time of the wiring and plumbing for the system, much of which you would have to do for an engine swap anyway if it's injected.
It is not cheap, but, still a lot cheaper than an engine swap.

[datsunrides]

Easiest would be a conversion using either the SU manifold or a dual weber/mikuni manifold. There are companies making basically throttle bodies for these. I ended up making my own manifold setup mostly because my U20 is also turbo and went with the SDS standalone with the crank fire option. Pretty simple to install and tune as it doesn’t need a laptop and can run in closed loop but not really self tuning.

[fj20spl311]

I have run an SDS with a Solex Manifold and TWM,Now Borla, throttle bodies. First with the bongs in the manifold and then using the bungs in the throttle bodies. Not much difference. I even bought a set of bungs....might do it on the Mule U20 I have for my 67.5 2L.

I too have wanted to put bungs in a SU manifold and use the SUs as throttle bodies....Using an SDS system as this would be my forth Set-up.

[Alvin]

Borla/TWM
Redline
Jenvey

[Pjackb]

If he’s looking for “easiest” with all the caveat that come with this I would have to think the TWM 2700 series would be best choice for TB since you can use your stock SU setup and just add crank trigger and a ECU of choice
https://www.borlainduction.com/2700-series.html#

6A9625A3-8765-4BE6-BD8D-70599337CD38.jpeg

For less “easiest” one of the local Roadster guy has this , says it pull like crazy
Modified 280zx intake on a L20B

4FA55152-B060-4E73-9782-D5DDCEBAA43E.jpeg

2EC96AAF-FB54-4FAD-8F19-0B545C951EF7.jpeg

[Pjackb]

Personally if I ever decided i needed EFI I would do a full kit like Omex that takes away a lot of the guess work
http://omextechnology.co.uk/Omex%20Gene ... 0v4_50.pdf

[Gregs672000]

I've always been intrigued with the idea of EFI and the promise of more HP and better driveability etc. I did review the link on the Borla site about carbs vs EFI. What I thought was interesting is that, on the engine they did their side by side testing on (a rotary) the Dellorto (or any similar sidedraft carb I assume) outperformed the EFI in the rpms that our engines would see. Only past 6000rpms did HP numbers change in the EFI favor. So while total HP was improved I would question the advantages if this is any indication. The nice thing about some of these newer systems is that the computer does all the tuning for you via feedback, and you can likely be much more precise. I know how frustrating carb jetting can be, let alone when you start messing with the nuances of emulsion tubes etc. However, working with someone like the Z-car garage folks shows what can be done on a dyno with some expertise and testing equipment, some of which are now much more available to us (wideband O2 set up for example). But that mainly applies to Mikuni type carbs, not SUs so much. If I were to compare the cost between converting to mikuni with the cost of the manifold etc, I would consider the conversion from SU to EFI to gain more tuning ability. Then again, there are carbs designed to replace the SU if one needs more direct fuel ratio control without the hassle of converting to EFI, the computer, fuel pump etc. Would money be better spent on a more adjustable carb and some dyno time vs EFI? Don't know, and for some money is not the issue! But once the carbs are set, unless you radically change your elevation they should remain in tune from a jetting standpoint, and may only need an occasional balance check.
The one clear advantage of EFI is its ability to adjust on the fly. I've been at the top of Mt. Shasta and elsewhere where my engine was choking on excess fuel, but for most of my driving it's fine.
Just my 2 cents...

[Daryl Smith]

Greg,
There are a lot of people in racing that stick with carbs for this reason, but, even they go EFI for their street cars...

The 'test' referenced by Greg....
https://www.borlainduction.com/media/carb_vs_fi.pdf

There is a big difference between everyday driving (mostly at part throttle), and a wide open throttle dyno run. I believe EFI would have a power and milage advantage over the carb at part throttle everyday driving. Add in programmable timing vs a standard distributor and that advantage increases.
Tho the 'newer' carbs are much better than they used to be and that advantage has shrunk somewhat, depending on the carb. For SU's? No question, in my opinion, EFI would have a huge advantage over most of the rev range, IF sized correctly for the engine.

Programmable timing does sigificanlty increase your installation and tuning costs as there are NO computers capable of self tuning ignition timing and Dyno time is needed to get it to it's best.

You can program a 'safe' timing map, as I did with the 1800 for several years, but, dyno tuning should show significant gains.

[Gregs672000]

You're absolutely right Daryl, clearly new systems are going to be better in many ways. I just thought it interesting that they were comparing only HP as the main reason to go EFI. And it does take upgrading several systems to take full advantage.