MY SDS EFI Install, Some details of my recent installation of a SDS EFI Options

[Joe Owensby]

Thanks for the comments and suggestions. Sorry for crediting the wrong Mark.

In SC, there are no emission inspections, so this is no problem. As far as cost goes, there will be no beating a set of carbs for being affordable. In fact, I am probably going to sell my set of Dell's, and I expect to get only a fraction of what I spent on the FI system. I just like FI systems. I don't have the numbers handy but the costs were in the ballpark of: $ 220 injectors, 1200 or so for the controller with valves sensors, etc. . I ended up spending a bit more because I had to buy an air box with runners, throttle, high pressure fuel pump (I think it was about 200 or so for the Bosch pump new), and the hoses and fuel pressure regulator- about 100 or so. While not mandantory, it would be nice to have an air/fuel gauge at least for tuning. I already had one that I bought to originally help me learn how to tune the carbs, so it was not an issue with me. Once the system is tuned you can take this off if you don't want to run closed loop. I have not yet decided if I want to run closed loop.

Again, the original FI systems were great. The system on my original engine probably had over 220,000 miles on it uring the first 15 or so years that I drove it. The only thing I did during that time was replace one injector, and bend the little copper followers on the throttle switch over a bit so they would be running on a non-worn set of contacts. I don't know the exact miles because the odometer died at 185000 miles several years before I parked the car.

The system on the engine I have runs pretty well, but I don't have it perfect yet. The engine really picks up at about 2000 RPM, and goes from there. It pretty much did this with carbs also. There seems to be a slight hump in the RPM values from 2000 to 2750, with a sort of plateau on up to 3500, and then about a 10% increase at 4000 and up. I am getting close to a good idle setting, but this has been the most difficult with a MAp reading of only 8 or so at idle. I almost have the cold start values tuned in by just noting the effects when I start it up in the mornings and adjusting accordingly.

Thanks for the suggestion on the air temp sensor location. I wondered if the best place would be in the manifold itself. When I had it in the location of the original cold start valve temperature sensor below the air box, it read 30 to 40 or so degrees higher than ambient. I may see if I can insert a thermocouple into the manifold to see what the actual air temp inside it is. I believe a simple relocation would be to just tap a piece of metal with the 3/8 pipe thread for the sensor, and then weld or pop rivet/epoxy it to the air box so that the sensor goes inside the box.

Thanks, JoeO

[Mark Henry]

Is emissions testing required in your locale for this car? Howabout fuel economy?

If emissions is an issue then you're best off to stick with stock FI. No AM system would pass visual unless you did an amazing job hiding things.

I know a guy who swaps out a stock engine every 2 years for his test. PITA

Not to be arguementive or to Hijack but how many monkys performing these tests are going to be old enough to visually determine if the installed system is OE or not.
Has any one ever seen the referance photos they use ? Do they evan have referances for 35yr old cars?

(IMG:style_emoticons/default/agree.gif) BUT If your dumb enough not to hide the controller, WB, ECU, wires, etc. a you could be asking for it.

I guess I'm being too literal, all the systems have this sort of disclaimer in the fine print.

[Brett W]

Most OBD0-1 cars all mount the IAT sensor in the plenum or in one runner farthest from the TB.

[davesprinkle]

Nice work. I had an SDS on my old Jeep. However you should relocate the air temp sensor back into the intake tract. Its needs to measure the exact air temp entering the motor not ambient.

(IMG:style_emoticons/default/agree.gif) Don't know how I missed that...yes it should on the intake somewhere before the TB.

This is true in theory, but in practice, putting the air temp sensor in the manifold will yield hot-start problems. This is because the temp sensor has a very slow response time -- a typical resistive temp sensor will take several tens of seconds to respond to a change in temperature. During a hot-soak, the air in the intake manifold can reach 175'F or so. When starting post-soak, the engine will evacuate this hot air from the plenum and will replace it with ambient temp air (say, 75'F) within a few engine cycles, taking only a few seconds. Meanwhile, your plenum-mounted air temp sensor will still report 175'F, thus forcing the ECU to underfuel by roughly 15% for this 100'F change in inlet air temperature.

Bottom line -- put the air temp sensor where it won't be affected by engine temp -- your firewall location is pretty good. No it won't be measuring plenum temp, but under running conditions, plenum temp IS ambient temp, within a few degrees or so, close enough to ensure that your fueling error will be substantially less than 1%. Easier to accept this than a 15% lean condition on a hot-start.

[bleucamaro]

Very nice write-up. If you are still looking for some constructive criticism, you might want to check your intake tract for vacuum leaks. I would think that you should have a moderately strong vacuum signal at idle, unless you are running a huge cam. Also, you will get more accurate intake temps by having the sensor in the intake tract.

Does SDS offer a cross over threshold that changes from alpha-N to speed density for low vacuum applications?

rdauenhauer: on oddball cars, they don't know what the heck they're looking at. I passed a 944S2 with a supercharger and piggyback on it in CA. Just leaned out to 14.7 AFR at lighter loads.

[davesprinkle]

Also, you will get more accurate intake temps by having the sensor in the intake tract.

As I mentioned earlier, this is a common misconception. It's easy but incorrect to propose that the intake tract location is more accurate. The reality is this: any air temp location that exposes the temp sensor to engine heat will yield LOWER accuracy. Unless you can find a temp sensor with a sub-1s response time (good luck with that), you should move the sensor away from the engine. Period.

Put the sensor under the front bumper. It'll work just fine there, and you won't have hot-start problems. (OK, I realize wiring logistics make the front bumper an unrealistic location. But at least get the sensor away from the plenum already. Maybe up under the vent by the decklid hinge?)

Use the air temp sensor to measure air temp. Use the engine temp sensor to measure engine temp. Don't confuse the two.

[Jake Raby]

I place the IAT sensor in the intake tract pre- throttle body... I have placed them in the plenum as well, but the proper location is in or near the air filter.

[Mark Henry]

I place the IAT sensor in the intake tract pre- throttle body... I have placed them in the plenum as well, but the proper location is in or near the air filter.

(IMG:style_emoticons/default/agree.gif) that's where mine is.

[Brett W]

While your premise is good about the heat soak, it isn't a problem with a properly tuned system. I can assure you I have never had a hot start problem with the IAT located in the end of the plenum, on NA or Turbo charged vehicles. You want the ECU reading the air temp closer to going into the chamber. Air outside of the TB doesn't matter.

Another thing that comes up is the type of sensor used? Are you using a metal or plastic sensor. The metal sensors do not react as quickly and they tend to retain heat more than the plastic sensors.

Having the sensor in the intake tract ahead of the Tb means greater spreads in the temperature readings as well. This means unless the sensor has a huge range of accuracy it will not read right on the far ends of the scale. Having the Sensor located in the plenum near an intake runner will yield much less radical temp swings.

Proper tuning of your IAT corrections will make all the difference in the small things. IAT corrections are like part throttle tuning. The more time spent getting those things right, the better the car will be as a whole.

[ConeDodger]

Is emissions testing required in your locale for this car? Howabout fuel economy?

If emissions is an issue then you're best off to stick with stock FI. No AM (After Market) system claims to have less emissions than stock, even though you could probably program it to pass easy. No AM system would pass visual unless you did an amazing job hiding things.

I know a guy who swaps out a stock engine every 2 years for his test. PITA

When I keep my foot out of it (hard to do) my mileage is as good or better than stock.

Probably one of the main reasons no aftermarket system claims to be better than stock for emissions is that at least here in California, the CARB (California Air Resource Board) has raided and seized records from businesses that make such claims. Big disincentive if you ask me.

[Smitty911]

Probably one of the main reasons no aftermarket system claims to be better than stock for emissions is that at least here in California, the CARB (California Air Resource Board) has raided and seized records from businesses that make such claims. Big disincentive if you ask me.

Another reason CARB should go away. I can see the need to monitor the Air Quality but these people are extorsionist.

[pbanders]

This is one of the most useful threads I've seen in a while. Couple of questions, if you've answered these, sorry, I didn't see them in the thead. How much did your install cost, both cash and time for install and tuning? Second, do you experience the same problem that D-Jet has with warm starts, where because the heads cool off much quicker than the cylinders and block if you let the car sit for 15-20 minutes after shutting it off (i.e. car is warmed up, you drive to get a coffee, and restart after a short while), that the ECU sees a cold head temp and richens the mixture too much for starting (requires opening the throttle to give it more air to get it to start)?

[pbanders]

Couple more things - how's your idle stability across a wide range of driving conditions? Right after cold start? Warmed up? Right after a hard run? Lights + accessories on?

Does the SDS have the capability to handle and control an active idle stabilizer?

How does the system handle altitude? No difference in running at 5000'+? I have to say that's something that modern systems are absolutely incredible at, they don't give a crap what altitude you're at.

[pbanders]

One comment about the air temp sensor. Air temperature is a secondary parameter in setting the mixture, across a full range of operation it has only about a 10% effect on injection pulse width in the D-Jet system. I'd be very surprised if would ever be off enough to prevent the engine from starting. The lack of correlation of head temp to proper engine temp on a T4 configuration motor has a much more significant effect, especially on warm starting.

[ConeDodger]

Brad,
I think one of the main differences is that original equipment efi, even some as old as ours perhaps - samples and adjusts 100's to 1000's of times per minute. The aftermarket systems do so much less frequently than OEM systems.

[jhadler]

Brad,
I think one of the main differences is that original equipment efi, even some as old as ours perhaps - samples and adjusts 100's to 1000's of times per minute. The aftermarket systems do so much less frequently than OEM systems.

Well, the D-jet is analog, so there is no sampling rate, it's continuous. But yes, the modern OEM systems have pretty high sampling rates.

-Josh2

[ConeDodger]

Brad,
I think one of the main differences is that original equipment efi, even some as old as ours perhaps - samples and adjusts 100's to 1000's of times per minute. The aftermarket systems do so much less frequently than OEM systems.

Well, the D-jet is analog, so there is no sampling rate, it's continuous. But yes, the modern OEM systems have pretty high sampling rates.

-Josh2

Sorry Josh, You are of course correct and I didn't mean to confuse the point by including dJet. I should have said even the earliest of digital systems sample many times more often than most aftermarket systems available to us. I hear Motronic is the best but I also hear it is very expensive.

[Mark Henry]

I'll try to answer some of Brads questions.

Altitude adjustment is automatic, all I've ever known The owners are first and foremost homebuilt airplane geeks, the biz is at one of the Calgary airports they fly almost daily in subaru powered aircraft. Their test mule for that has gone from a 4cyl to a 6 turbo. Plus a bunch of cars of course...
I have EM4-F crankfire that I did just after 914club when on line. It would have been $1600 then, but I did a group buy and got 25% off. I had a NB but later bought a WB that was $450.
With crankfire the install is a bear because you need to fab a trigger mount and disc, engine out and fan apart. I could easily do an ugly install in a day now on a fuel or MSD only system.
Has never once failed to start, hot or cold. Always takes two revolutions as it has to "see" the sync magnet.
Control an active idle stabilizer? No clue I use the stock bleed valve.
Idle has always been stable.
Cold Start has always been like a beetle carb, a couple of pumps and it fires. Colder you have to feather the gas for 30sec. never drove below 0*C much.

I've had a fresh 914 2.0 "scrapyard special" engine with a scat C-25 cam and it had the power of a fresh 2.0 djet. I used all d-Jet intake.
I sold it and then I had it on my stock 1.8 L-jet with the d-jet plenum. Across the board you wouldn't know the difference, except for the cold start. There L-jet ruled.
The 1.8 I drove the last 3 years without the programmer or WB hooked up, once a year was all I checked.

Tuning was real close right out of the box, didn't really spend a whole lot of time on it, tweaked it on the fly, it was surprisingly fast. Crankfire is set once and forget it Just the fuel values for the most part. Only issues I have had was program error. I set the fuel cut rpm to 500 for security during storage and forgot about it, doh.

I'm moving all this gear over to my bug project and I may have the SDS back going this year, but in a bug. See my signature for that story (IMG:style_emoticons/default/rolleyes.gif)
we'll see what happens and If I find the time to do the wee beastie.

PS I had it mounted in the stock box with a hole in the bottom, never an issue with moisture, but I would never do it again. PITA

[ConeDodger]

Mark,
What kind of number would a group buy take?

[Mark Henry]

Mark,
What kind of number would a group buy take?

I can't remember, 10 maybe, I only made it to 7 or 8 which was 20% off. Ross liked me and gave me my system at the 25 (IMG:style_emoticons/default/shades.gif)
It's on the price list page.

Would I organize the group buy again? Hell NO! PITA BTDT.... (IMG:style_emoticons/default/smile.gif)