Should I EFI

[T77911S]

RUF IC
K27 7006
Early B&B header
Would lime to also upgrade cams and eventually go twin plug.

Starting to consider EFI, not sure why, maybe just need to spend money.
I have a good running euro cis system and I know cis extremely well but efi knowledge is limited and certainly not into tuning efi.
Also scared I am opening a can of worms that is going to lead to lots of trial and error tuning that I am not really wanting to do since I can drive and enjoy the car as is.

What I would like out of the car is better throttle response and less turbo lag/broader power band. With the latter I realize I will have to change turbos.

[kevin930t]

Why not seems like thats the direction alot of other 930 owners are going ,reliability is there you can make tons more pwr.Fuel management system electronic ingnition.The list goes on.

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[JacobS911]

F!@K IT! Go for it..

Been kicking that around in my head as well actually. Other than cost.. I don't see a reason not to if you're keeping the car for long time. I need to do body restoration at some point in the near future so EFI is a loooong way off.

Keep us posted on the update if you go forward with it!

[dos531]

Yes.

[smurfbus]

I already have most of the efi hw in my car but now that my headers are modified from single to twin wg I have urge to stay with my CIS and stretch it as far as I can. I already have timing map (123/TUNE) and fueling map (AIC1) so efi would bring better breathing, more fuel and larger maps/tuning plus e85.

[xbmwguy]

You will never look back!!!

[Bucketlist]

I know the feeling......wanting to go efi......butt...
Our cars are somewhat similar, RUF intercooler, 7006 turbo, dial-o-death, zork.
Mine is already twin plugged with the twinfire distributor, twin cdi boxes and twin coils, lots of plug wires.
This is old school cool, don't really want to change it.

For now I tell myself maybe another one will come along that I can play with, one that needs this work......I could go efi with itb's, cop, maybe even meth. Really sounds like fun, better start saving my money.

I don't even notice the lag or performance problems...just listen to the sweet sound of the zork, popping on decell, flames, turbo whine...... maybe i'm just old and senile?

[turbobrat930]

EFI is nice. Do yourself a favor, and buy a few books on basic EFI operation, basic tuning, etc. Read up on it, get to know it. And BEFORE you buy anything, pick your tuner. then buy the system that HE is familiar with!!!! You will save a lot of money and hassles by doing that.

[Mocker]

I've been contemplating it, but for now I'm going with a Garrett GT35, and new BB headers/muffler, Tial wastegate and mods to clean up the intake/BOV. Previous (original) owner did 90s-era mods: cams, crank and P/Cs, Andial I/C and fuel enrichment, so the steps I'm taking are meant to get a broader and more powerful powerband, by modernizing some things that are really pretty much "bolt on" (although some of the internals have been changed).

I see EFI as non-reversible, or at least not-easily reversible. I'm excited to see what I'll get with the new setup--should be ready next week (after being in the shop for months--I had a bit of a laundry list ). Looking to get around 375HP with these mods; that will be good enough for now.

[Rich76_911s]

Since my car is being a garage whore (not queen) right now I've been thinking about it too. Also since my car isn't running well if I were you I'd keep my well-running car and enjoy it as is. When CIS failed me I'd take that opportunity to swap to EFI. In the mean time learn as much about as you can.

I figure cost probably starts at about 5K for a mega squirt DIY and can easily get to 10K or more, and that's before you've paid someone to tune it.

I'm not trying to be a smart A$$ or a Doubting Tom. If I had the money to do it, I'd have done an EFI swap already. But here are a couple of questions that have been in my mind:

How much is the performance gain in doing an EFI swap?

Is the car going to feel like an entirely new beast, with markedly better driving characteristics?

Has anyone every done a before and after dyno run to show how much and where you get performance gains from EFI?

Are the benefits attainable by a DIY'er or do you need to have a tuner to actually get these things to run well? Cold start, warm start, partial load, full throttle, idle, etc. My impression is that general knowledge can get a car running, but beyond that, you really need an expert. And depending on the expert you find, the results can vary. One of the turbopalooza guys had taken his Motec car to several experts in the North East but was still unsatisfied with the results.

If you need a tuner, then I get the feeling that the first thing to do is find a tuner you're going to use, then work backwards and find the systems they work with. It doesn't seem easy to find a tuner with much experience in air cooled 930's.

Those are some of the things I have bouncing around in my head. I hope that my asking them helps the OP.

[Tippy]

Originally Posted by Rich76_911s

I figure cost probably starts at about 5K for a mega squirt DIY and can easily get to 10K or more, and that's before you've paid someone to tune it.

That's a lot higher than my experience. "jpnovak" has put many systems together far cheaper.

I'm not trying to be a smart A$$ or a Doubting Tom. If I had the money to do it, I'd have done an EFI swap already. But here are a couple of questions that have been in my mind:

How much is the performance gain in doing an EFI swap?

Well tuned CIS vs well tuned EFI, performance gain would probably only be in the midrange where your AFR's get out of whack.


Is the car going to feel like an entirely new beast, with markedly better driving characteristics?

Hell to the yes! I drove my friends very well-tuned CIS 965, and his drove like a turd. Throttle response was bad, the car had far less low-end torque (mind you, he has stock 3.3 port heads, mine are Carrera 3.2's). There's no comparo in snappiness the EFI can deliver if properly tuned. Let's not compare my MPG's to his.
I've pulled 28 highway.

Has anyone every done a before and after dyno run to show how much and where you get performance gains from EFI?

As mentioned above, only the midrange will you see an increase in power if the CIS gets pig rich there once on boost. At WOT, both CIS and EFI should deliver about the same hp, unless the inlet tracts are different between the two (using a pancake on CIS vs Carrera 3.2 or ITB's with EFI). But, with EFI, hp is virtually limitless!

Are the benefits attainable by a DIY'er or do you need to have a tuner to actually get these things to run well? Cold start, warm start, partial load, full throttle, idle, etc. My impression is that general knowledge can get a car running, but beyond that, you really need an expert. And depending on the expert you find, the results can vary. One of the turbopalooza guys had taken his Motec car to several experts in the North East but was still unsatisfied with the results.

You don't need to be an expert, just have a basic understanding of what the engine needs. Heck, most modern systems will tune themselves either real-time, or using datalogs processed through them while the car's not even running in seconds which you can load and try the new tune.

If you need a tuner, then I get the feeling that the first thing to do is find a tuner you're going to use, then work backwards and find the systems they work with. It doesn't seem easy to find a tuner with much experience in air cooled 930's.

Tuning a 930 isn't a lot different than other makes, other than liking lots of timing and running richer than newer engines due to the older hemi head design. A good tuner will understand this quick.

See in red

[T77911S]

Rich you kind of hit my feeling about it on the head.
Problem is here on the east coast I really only know of one shop that may be able to help tune.
We just don't have the shops like the west coast guys do.

I have looked at complete systems and then I have read about some guys doing it a lot cheaper by sourcing the parts themselves.
Not that I am going cheap but I would have to if I tried to do the Cams at the same time.

Was also thinking about a Garrett turbo. My 7006 does not have a lot of miles on the rebuild and neither does my CIS system. Also 6 new injectors.

I have an 88 325is I am not driving. Thinking about selling that to fund this project. My other option is to keep this car and rebuild it.

[Tippy]

Here's my $0.02.

Nothing is hard to learn, it's just a lot to learn. Meaning, if explained well, the theory of how each parameter works, it's not hard to digest at all.

Seriously.

If you know a little about electronics and a little electrical theory, it's virtually nothing to learn. If you know how engines work and their transients, that helps too.

I was electrically dumb when I did my install. I learned on the fly from the screen of an iPhone 3GS. No *****!

So, if I can do it.......

If you are a no-headaches type person, this may not be for you. Just crack open the check book and write away for your conversion to save the headaches!

If you like a challenge, and think of it as an elephant that you eat one bite at a time, learning, installing, and tuning EFI is something that should be doable.

The one thing to consider, is you are not alone. The EMS of your choice will have support, and with the connection of the interwebs, you have unlimited support for free 24 hours a day on issues if one were to arise.

[dap930]

There are plenty od people here that can help you out if you run into a snag. We who have already done EFI conversions have already been through the steep learning curve. Depending on what system you choose, someone should be able to supply you with base VE, AFR and Spark Timing maps to get you going.

[Jeff NJ]

I have spent a lot of time and money over the past few years upgrading, repairing and modifying my car to get it to run right. It was stock when I bought it and I have added a bunch of bolt ons (IC, K27HFS, rarlyl8, WUR, 1.0bar TiAl, etc) that have made it a blast to drive as-is.

At the moment, it runs great, so I am in the same boat as you in that I have a modified car with CIS that runs well right now. While I sometimes get the bug to improve the car, or add HP, I am not touching ANYTHING until I need to at this point. I am having too much fun actually driving the car! Yes, it could be faster, and yes, a well sorted EFI system will be more reliable than CIS, but I just dont see the point if the car is running and you enjoy it.

So I am going to go against most that have posted their opinions and say drive the p!ss out of it and if you have to have a winter project, or something else needs to be done to take it off the road, then decide what to do. Why take a well running car off the road for a significant amount of time when you could be driving it instead?

[Rich76_911s]

Cory - Thanks for answering the questions. I'm certainly an outsider looking in and I'm just trying to get my head around it all. In no way am I trying to poo on the EFI parade.

Do you have any recommended reading on getting up to speed on electrical theory?

You're really pissing me off that I sold 3.2L heads and a 3.2L intake to fund my engine rebuild.

Thanks again!

T77 - Maybe check with Zuffenhaus in Monroe, NC. That area is flush with a lot of automotive experts if they can't handle the EFI tuning.

[Tippy]

Originally Posted by Rich76_911s

Do you have any recommended reading on getting up to speed on electrical theory?

You can find other EMS manufacturers documents, but for sure, I know MegaSquirt has the "MegaManual" and "MSExtra" documents.

http://www.msextra.com/manuals/

All the electrical theory you need to know is in them.

A few things one should study (I say this lightly, there's not a ton to understand, just the basics) on top of EMS in electrical theory IMO, is:

1. Ground loops and how to avoid them
2. Grounding period
3. EMI/EMF noise


The hardest thing to do once you have a good grasp, is figuring out ignition changes. Since you can run just about ANY ignition system known to man, they ECU is very configurable to handle the breadth of these systems. You have to spend a little time figuring which wires need to be hooked to which.

So,with that said, go with COP ignition right off the bat. This will save headache in the future and tearing into a loom that you made that looks really nice if you were to change ignition systems from the first install. Not fun ripping back into one.

[m42racer]

Originally Posted by T77911S

RUF IC
K27 7006
Early B&B header
Would lime to also upgrade cams and eventually go twin plug.

Starting to consider EFI, not sure why, maybe just need to spend money.
I have a good running euro cis system and I know cis extremely well but efi knowledge is limited and certainly not into tuning efi.
Also scared I am opening a can of worms that is going to lead to lots of trial and error tuning that I am not really wanting to do since I can drive and enjoy the car as is.

What I would like out of the car is better throttle response and less turbo lag/broader power band. With the latter I realize I will have to change turbos.

The first thing you have done correctly is to identify your performance needs. Now set a budget.

The one part of this that is the decider is the Ignition system. What are you going to do and use? The fuel side is all about the delivery. If the CIS delivered the fuel correctly and the AFR's are in check, the gains will be minimal. But alas, this is not the case. The electronic fueling will always win that contest. But with electronic fueling and weak ignition, you have gained nothing. Of the two, throttle response is more about ignition than fuel. What ignition are you using or going to use? Decide this first then work from there.

Turbo lag is about getting the engine to react quicker in combustion. You need exhaust energy to get the turbine to spin. Changing the turbine size helps but clips off the RPM range that can be safely used.

If the cams you have have a LSA of at least 114° you could advance the intake some to help with the lower end response too. But this will be a small change due to other constraints.

My advice is to start with the Ignition first. This same ignition can be incorporated into a full EFI system later. Then if any change can be done to the cam timing and the turbine housings, do this next. Once you have reached these limits, then re assess where you are falling short and address these areas next. Do it in a deliberate way so you FIX what you need fixing and not head down that rabbit trail so many end up. That just wastes money and gains nothing but headaches.

[Tippy]

Originally Posted by m42racer

The first thing you have done correctly is to identify your performance needs. Now set a budget.

The one part of this that is the decider is the Ignition system. What are you going to do and use? The fuel side is all about the delivery. If the CIS delivered the fuel correctly and the AFR's are in check, the gains will be minimal. But alas, this is not the case. The electronic fueling will always win that contest. But with electronic fueling and weak ignition, you have gained nothing. Of the two, throttle response is more about ignition than fuel. What ignition are you using or going to use? Decide this first then work from there.

Turbo lag is about getting the engine to react quicker in combustion. You need exhaust energy to get the turbine to spin. Changing the turbine size helps but clips off the RPM range that can be safely used.

If the cams you have have a LSA of at least 114° you could advance the intake some to help with the lower end response too. But this will be a small change due to other constraints.

My advice is to start with the Ignition first. This same ignition can be incorporated into a full EFI system later. Then if any change can be done to the cam timing and the turbine housings, do this next. Once you have reached these limits, then re assess where you are falling short and address these areas next. Do it in a deliberate way so you FIX what you need fixing and not head down that rabbit trail so many end up. That just wastes money and gains nothing but headaches.

Great points on the ignition, but I'm going to have to differ on what makes good throttle response. I can make millisecond changes in my throttle transients and either make the engine rev poorly, or like an ITB. Which leads to ITB's. Nothing allows an engine to rev faster since fuel and air are getting into the cylinders faster than common plenum. Not sure I understand how ignition could really play that much of a part, unless you are speaking about timing advance? But again, timing advance won't do it all!

[m42racer]

Originally Posted by Tippy

Great points on the ignition, but I'm going to have to differ on what makes good throttle response. I can make millisecond changes in my throttle transients and either make the engine rev poorly, or like an ITB. Which leads to ITB's. Nothing allows an engine to rev faster since fuel and air are getting into the cylinders faster than common plenum. Not sure I understand how ignition could really play that much of a part, unless you are speaking about timing advance? But again, timing advance won't do it all!

You need to understand then fundamental work of the ignition system.

Its to generate temperature inside the combustion chamber. The spark plug initiates the flame or start of the burn but its temperature that ignites the mixture. The more temperature the more the combustion intensity and the quicker the event. This is why Inductive Ignition has a very long burn event. The energy released within the chamber is a lot less than CDI as its based upon the coil winding size and therefore the temperature created is less.

Many other variables have an effect on the engines performance but none as much as Ignition. Its the very last function before combustion occurs.

Ignition advance lead changes when the ignition event happens. This can be set by start, mid or final. This can help as it starts the ignition when cylinder pressures may be greater at the time of complete or near complete combustion , hopefully after TDC. This then pushes on the Piston with greater force. More torque is then created.

Now think of the ignition timing, cam timing and compression ratio all "fixed" at the time of complete combustion. What else could you improve upon to make the explosion greater.

Too many take the ignition system for granted. "As long as the engine does not misfire, its good to go". The Ignition is a huge player in the way an engine performance can be
influenced.

All we are trying to do is to create the highest level of explosion within the cylinder hopefully under some sort of control. We create the pressure by the swept and compressed volume, the mechanical ability to pump as much air into the engine in a given time with the fueling volume based on a safe AFR number. The rest is up to the amount of temperature we can induce from the Ignition system.