L_perm

I currently have the top and front of my engine off for a comprehensive refresh. The parts count/cost has gotten high enough that I am we'll within range of Carl's TEC GT engine management system. That is, if you subtract the cost of what that system replaces from my current list of parts, I'm within about $1,500 of doing the whole refresh and ending up with Carl's ECU plus his fuel rails--one fuel regulator (no need for dampers), 24lb new injectors instead of refurbished old ones, no distributors, new coils at the plugs, no LH computer, no ignition computer, new injector harness, MAP instead of MAF sensor, and an easy path to a supercharger someday.

I wasn't planning on replacing the coils, LH computer, injector harness, fuel rails, or ignition computer right now, but when you add up the cost of doing that, you get to approximately the cost of doing everything with Carl's system. Since I'm within range and not averse to the idea of checking these things off too, I'm seriously considering the TEC GT direction. (It's entirely possible I need a rebuilt LH anyway, as my car stalled three weeks ago and wouldn't restart.)

If I'm spending so much to put back the old system, then why don't I add $1,500, effectively replace/negate a few more parts, and end up with new engine management? That is the question.

Any advice? Testimony from those who have Carl's system?

Thanks,
Louis

FLYVMO

I used the TEC3R on my 86.5 and it was a worthwhile upgrade, new wiring, sequential injection, smoother running at idle, better fuel economy and found extra power to boot (added knock sensors), full-time wideband O2 control etc. Downside was that it takes quite a bit of tuning to get there (open road AND dyno tuning). The Tec GT is slightly different but I would definitely say it is a worthwhile upgrade over the stock system. Go for it!

If I was to put another aftermarket ECU in at this point, it would be Holley's Dominator EFI. Many more features although slightly more expensive.

Cheers!
Carl

hacker-pschorr

FWIW I re-wired my 81 to have the fuel & ignition from an 85 EuroS just so I could shark tune it.
I've also installed / tuned other cars with aftermarket systems.
Current projects are megasquirting my 79 and picking something for my replica Cobra to replace the stock Ford system.

Long story short, I have the experience and capability of installing any 3rd party ECU on my recently purchased 87.

That being said, I'm sending in both my brains & LH for rebuild / refresh, new injectors, I'm going to pull my harness and rebuild every end while re-do the sheathing, replace the knock, HAL, and sensors.....

Basically I'm in the same boat as you, and even with my experience with aftermarket systems I'm sticking with the stock setup because even if I supercharge my car, the power goal is only 550rwhp which is perfectly within range of the stock system with a Shark Tuner.

IMO with regards to any 87+ car, any gains over the stock setup simply means something wasn't working 100% originally and the problem wasn't fixed, it was replaced.

The #1 reason to ditch the stock system is on a highly modified car, and or one using a custom intake like Mike Simard's or Greg Browns that simply will not work easily with the stock MAF.
Another good reason is if you want to experiment with different fuels like E85 and need an engine management system that takes into account ever changing ratios of gasoline and ethanol.

Just my $.02

L_perm

Thanks for the input guys. If I supercharge someday, then I won't be looking for more than about 150hp--pretty mild in the interest of motor longevity.

Honestly, one of the most appealing aspects of new engine management would be its ability to take care of the engine better--timing based on load instead of RPM, for example. Are the benefits for the engine significant?

Simplifying the fuel distribution is also appealing. I have two bad dampers. Getting rid of the MAF is a plus. Computer control instead of distributors...

Ducman82

I am running mega squirt 3X , fuel sequential and all that jazz.... Aftermarket is great, but the tune time is a hassle. Dyno time is expensive. But if you know what you are getting in to, and understand the basics of tuning, I say go for it.

Lizard928

Unless you need to, I am going to vote no.

I have converted a number of 928s. Upgrading can be great, but the tuning and time it takes especially on a first install can and will likely be massive to get rid of all the little gotchyas.

There is gain to be had, but shark tuning will give you 87% of what the other systems will give you if you know what you're doing.

jcorenman

Greg's intake was tested with stock ECU's with Sharktuner "Alpha" system, on Rob's stroker and our GT. It is also being used with an ITB setup in the UK.
No MAF, fueling and ignition are based on throttle and RPM adjusted for temperature and pressure.
Info here: http://jdsporsche.com/sharktuner%20alpha.html

L_perm

Thanks for the replies. I'm a bit confused, I guess. I was under the impression that the TEC GT ECU could be added "plug-n-play" style. That is, if my car is not modified, the "base tune" would suffice. Is there no such thing as a base tune? Do I have to start from scratch setting every parameter available with the system? The marketing description at 928 MS doesn't read that way.

My interest in the unit is not for performance. I'm interested in getting rid of some old technology and unwanted parts in favor of something that is more modern and reliable. Any performance gain is icing on the cake.

Like I said earlier, if, for the same money, I can put either the old system back, or put in the new system, then does it make sense to: put in a rebuilt MAF, the same TPS, the same fuel dampers, the same coils, a rebuilt LH computer, the same wiring harnesses, rebuilt injectors, the same fuel lines and rails, the same distributor system, when I can upgrade or get rid of this stuff?

My thinking is: the primary difference between 1991 and 2014 is the electronics. I have a very sound mechanical platform in the 928 S4 drivetrain that I can future-proof to some extent by upgrading the electronic management system and getting rid of some parts that are only necessitated by the continued use of the old management system.

But, I'm not a tuner. Am I SOL?

Louis

FLYVMO

When I installed my Tec3r system, I hade never done any tuning before. I did read...I read A LOT of tuning books, talked to Electromotive tech support, and learned as much as I could before the system was installed. Once I was confident I knew enough (and had my maps examined by Electromotive), only then did I power up the engine and began the actual tuning. You can get an engine to an "adequate" state fairly quickly, but it will take several tuning sessions, both on a dyno and road tuning with a person in the passenger seat adjusting the software on a laptop. The steady state running and idling when warm is fairly easy....it is the cold startup enrichments, acceleration/deceleration enrichments that take time to get right.

A big selling point of going aftermarket for me, was modern electronics, fresh wiring (and larger AWG size), new connectors (not 30 year old plastic), additional inputs and outputs for possible future upgrades. For me personally, I did not feel it would be productive to put 25-30 year old electronics (rebuilt or not) in my car.

I think in the end it is up to you and what you value the most, and what you want to get out of the car. Going with an aftermarket ECU is completely reversible (as long as you tune carefully), so if you are worried about resale value, the stock system can always be re-installed at a later date.

Just my personal experience and opinion...

Cheers!
Carl

jcorenman

Louis,

What is your goal for the car? A garage queen or a reliable driver? Keep it forever or enjoy it and then pass it along?
Or maybe an endless project because you like working on cars?

What shape is the engine wiring in? Is the harness brittle and falling apart or in good shape?

It is hard to imagine that an aftermarket ECU is a step forward in terms of reliability. The stock stuff -- with a rebuilt LH -- is pretty bulletproof.

If you don't typically keep your cars forever, consider that the 928 market is small, and for modified or non-stock cars gets tiny pretty quick. There are not a lot of folks who really understand these cars, add in aftermarket electronics and most of those lose interest.

L_perm

Thanks again guys.

I want the car to run like it should, and I want to be able to drive it without any significant concerns about reliability. I don't have a baseline reference on many of the important parts--water pump, alternator, fuel pumps, thermostat, fuel lines, all sensors, etc. The car stranded me three weeks ago. That got me started tearing it down, which I had thought of doing anyway for said reasons, and I now want to do what I can to achieve peace of mind. I also want to know the car inside and out.

I plan to keep the car for a long time. I've always thought the 928 was cool. I want to do some amount of customization. I have the GTS mirrors, and I have a set of Koni shocks and Hypercoil springs. I have the x-pipe and high-flow cats. (I inherited the x-pipe from the PO and added the cats myself.) I want to redo the interior, but my preferences make that big bucks, and reliability comes before cosmetics. I want to do something with the wing...and so on...

So, I'm in a process that will last for a while, not to mention maintenance and needed repairs. My hatch window is leaking and has warped the top trim piece on the hatch. My passenger floor board was wet recently. I'm going to remove the CE panel for cleaning and figuring out the leak situation down there. My right headlight is full of condensation. I need to paint my intake. Hood light is broken. I have new motor and tranny mounts, along with an oil pan seal, ready to go on. I have one of Jerry's cowl covers ready to go on after the current work. The original cover was junk--wow!

There is plenty to do, and that is part of why I purchased a 23 year old car--I like doing the work, learning how to do it, being self-sufficient. I'd like to impart these things to my 4-year-old. I'd like to go to a shark event someday with my son in a car that is a nice specimen, familiar, but with my own touches. I've entertained doing a DE in the shark at some point--who knows.

As far as the harnesses go, they look fine for their age--no obvious damage. But, I've read here and there where harness replacements have surprising benefits, as the degradation over time is subtle.

I've effectively given up on new engine management. Putting back the old system now looks pretty easy by comparison. I guess I should test my coils to make sure they're okay. What is the replacement recommendation on them?

Thanks,
Louis

Hilton

Don't waste your money.

Another rennlister installed the TecGT system on a stock car a few years ago, 928mac (Brad Haugen).
It wasn't plug and play, and AFAIK, he never did get it running as well as a stock 928.

One of his threads here:

https://rennlist.com/forums/928-foru...d-updated.html

Aftermarket EMS has a place - but that place is for running (heavily) modified engines. The stock ecu setup has a lot going for it, and thanks to JDS in the UK, we can tune the LH variant ecu's on the car for most modifications. Heck, even Tuomo with his twin-turbo monster and somewhere north of 600rwhp is using the stock engine management.

jcorenman

Louis,

Cool, thanks. I think this has been mentioned before, but the things are most likely to leave you stranded are fuel pump(s), LH (if not rebuilt), relays (ignition, LH, EZK), engine-harness connectors. And fuel lines of course, for safety.

The next level is all the stuff that will cause it to run or idle poorly: The rubber bits under the intake, dirty/clogged iSV, flappy, an aging MAF, old/cracked ignition wires or connectors, etc.

The ignition stuff is all pretty robust, other than aged wires, but distributor caps and rotors need checking and replacing as needed. I haven't run into a bad coil but some folks have, and I replaced the coils in our GT at ~200K miles just in case.

Cheers, Jim

BC

95% of the 928s out there have layers of PO idiocy in the wiring. The ECUs cost several hundred dollars to rebuild total, and even if it's not failed, it acts wield and you chase little gremlins.

Ripping all that out and starting fresh with proper wiring procedures and real, automotive grade wiring and connectors is a GOOD idea.

I don't have personal proof (yet) of this fact, but for some tuning here and there, great, use a shark tuner.

When you are changing the fundamental parameters of this automotive package, you need a newer more modern system.

Yes, tuning is hard. A new Mercedes has 20 million lines of code.

Carl Fausett

It isn't plug and play, but its pretty close. The Electromotive system does auto-generate the first map for you, and its good enough to start and drive the car safely. Going to the dyno after the auto-tune has been generated, we are always impressed by how good it is. Since we introduced a TecGT kit for the 928, I have been installing them on 928's and 968's for 6 years. I also have one on each of my own 928's, the racer and the street-legal '91 GT.

To keep the stock LH and the stock EZK is to say that computers have not gotten faster since 1988, and that you are alright with a system that cannot pull back timing if it sees a lean condition. Because that's what you've got. (tip of the iceberg of the features you will be missing, stronger spark, more accurate ignition events (ignition rotors currently lag in real-time as they are driven through the timing belt drive, etc)

No matter how much sharktuning you do, we've learned things since that system was designed, technology has marched on, and computer technology has gotten much better. I do not wish to stick my head and the sand and pretend that the 1988 system is "just as good" as a modern EMS. It isn't.

...and a lot of the cost of the after-market system can be made up from the replacement cost of keeping the old LH and EZK going. The injector wiring harnesses are brittle and often need maintenance - and they are pricey. You get a new one with the new Engine Management. New coils too. Eliminates the distributor caps and rotors (which you will never buy again). And more. If you have a LH fail of need your MAF rebuilt or replaced - you are almost there to the cost of a new engine management.

But, not to review it all over again here. I was asked once before what are thew advantages over the stock system, and I wrote this response in 2008:
https://rennlist.com/forums/928-foru...tromotive.html

But keep in mind, I'm a tuner. I change the engine. I change the exhaust. I change the cams and I often add boost. If I was dealing with a dead-stock 928 that is just used for joy riding - I have absolutely no problem with the stock engine management. It functions just fine. It is just getting expensive to maintain.