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I'm kind of at a crossroads here and I need some input. For boosted cars there seems to be a consus that a vampire and ownership of or access too an eprom burner, shark tuner are a necessity for tuning and detonation prevention of boosted cars.
The costs of these items coupled with the limitations of the stock MAF and aging computers, makes me wonder what the advantages of staying with modified stock components, over installing another engine management system are. E.g. Tec GT , megasquirt ,etc..
With stock stuff, you dont need to be an expert tuner to pull out of it what you can...
With OEM stuff, you get perhaps 90% of the way there, and save a # of thousands in hardware and wiring, and more many many hundreds to thousands in dyno/etc effort completing it.
I'm kind of at a crossroads here and I need some input. For boosted cars there seems to be a consus that a vampire and ownership of or access too an eprom burner, shark tuner are a necessity for tuning and detonation prevention of boosted cars.
Knock sensors are not necessary for proper tuning. In fact, the professional tuners I know disconnect or disable knock sensors when tuning. They are only active on once everything is sorted to protect against something failing like an injector which starts to spray less or you accidentally pour in 87 octane when the cars was tuned for 93.
My supercharged 81 (with the same ECU's as your car) and Todd's twin turbo do not have knock sensors.
Shark Tuner and chip burner are necessary to tune your car, along with a professional tuner and they don't typically come cheap but the good ones do not take very long and they charge by the hour.
Originally Posted by cpayne
The costs of these items coupled with the limitations of the stock MAF and aging computers, makes me wonder what the advantages of staying with modified stock components, over installing another engine management system are. E.g. Tec GT , megasquirt ,etc..
This is correct, for the most part.
The piece of the puzzle left out of using a 3rd party is you are now tuning 100% of the map from scratch instead of just the boosted areas, and yes this can be a big deal. I see people all over car forums downplaying this but they simply do not appreciate the work involved with tuning a car from scratch. Making sure the maps are fully tuned for every possible scenario from ice cold mornings to death valley heat at all engine temperature ranges. Most cars I come across with 3rd party ECU's are tuned with the "good enough" attitude and they keep a laptop handy just in case. That doesn't' cut it for me and the reason why I went with the twin dizzy arrangement for my 81. I wanted to start with the base maps.
Todd has spent hundreds of hours tuning his turbo 928 and he's been doing this for the better part of three decades.
All that being said, my next plan is to ditch this setup on my 81 and to with the AEM Infinity ECU. Why? The 85/86 setup is a pain in the *** to shark tune and frankly I'm stick of dealing with it. You cannot tune fuel & ignition at the same time and all the messing around with a ribbon cable and jumper leads is frustrating. This isn't a knock against the Shark Tuner, it's simply the only way to connect up & tune those brains. The 87+ units can be tuned in the box without taking anything apart, on the fly, both brains at the same time. Hindsight I should have gone with those brains for my car (we debated it) and I'm still thinking of going that route.
Why am I going with AEM? My local tuner at Beyond Redline is about as good as they come and that is his preferred computer. Turbo Todd is also looking into ditching Autronic for AEM after what he's seen it do with other cars, like a 1,500rwhp street driven Supra built & tuned locally.
Todd has been researching ECU's for the 928 for about a decade, and in his opinion they are on the forefront of technology. The only other option for his car is MOTEC which is considerably more expensive.
The basic AEM brain is around $1,000. I think MS runs around $600. The money you save will be spent in labor hours wiring up the car. Looking at the photos this may be a moot point since you already have a wiring nightmare on your hands fixing the stock setup.
You may also get some good money for leftover parts like the MAF, brains and harness.
If I were you, I would shop around for a tuning shop and ask them what they use. Having a local expert for whatever system you go with will do you more favors than anything else.
Knock sensors are not necessary for proper tuning. In fact, the professional tuners I know disconnect or disable knock sensors when tuning. They are only active on once everything is sorted to protect against something failing like an injector which starts to spray less or you accidentally pour in 87 octane when the cars was tuned for 93.
My supercharged 81 (with the same ECU's as your car) and Todd's twin turbo do not have knock sensors.
Shark Tuner and chip burner are necessary to tune your car, along with a professional tuner and they don't typically come cheap but the good ones do not take very long and they charge by the hour.
This is correct, for the most part.
The piece of the puzzle left out of using a 3rd party is you are now tuning 100% of the map from scratch instead of just the boosted areas, and yes this can be a big deal. I see people all over car forums downplaying this but they simply do not appreciate the work involved with tuning a car from scratch. Making sure the maps are fully tuned for every possible scenario from ice cold mornings to death valley heat at all engine temperature ranges. Most cars I come across with 3rd party ECU's are tuned with the "good enough" attitude and they keep a laptop handy just in case. That doesn't' cut it for me and the reason why I went with the twin dizzy arrangement for my 81. I wanted to start with the base maps.
Todd has spent hundreds of hours tuning his turbo 928 and he's been doing this for the better part of three decades.
All that being said, my next plan is to ditch this setup on my 81 and to with the AEM Infinity ECU. Why? The 85/86 setup is a pain in the *** to shark tune and frankly I'm stick of dealing with it. You cannot tune fuel & ignition at the same time and all the messing around with a ribbon cable and jumper leads is frustrating. This isn't a knock against the Shark Tuner, it's simply the only way to connect up & tune those brains. The 87+ units can be tuned in the box without taking anything apart, on the fly, both brains at the same time. Hindsight I should have gone with those brains for my car (we debated it) and I'm still thinking of going that route.
Why am I going with AEM? My local tuner at Beyond Redline is about as good as they come and that is his preferred computer. Turbo Todd is also looking into ditching Autronic for AEM after what he's seen it do with other cars, like a 1,500rwhp street driven Supra built & tuned locally.
Todd has been researching ECU's for the 928 for about a decade, and in his opinion they are on the forefront of technology. The only other option for his car is MOTEC which is considerably more expensive.
The basic AEM brain is around $1,000. I think MS runs around $600. The money you save will be spent in labor hours wiring up the car. Looking at the photos this may be a moot point since you already have a wiring nightmare on your hands fixing the stock setup.
You may also get some good money for leftover parts like the MAF, brains and harness.
If I were you, I would shop around for a tuning shop and ask them what they use. Having a local expert for whatever system you go with will do you more favors than anything else.
Good idea!. I hoped my inquiry would bring out all the philosophies and approaches.
You might try contacting RL user "Raceboy" who makes Plug-and-play VEMS setups for all the Porsche models including 928.
Complete stand-alone engine control (every possible parameter, and you can even come up with new ones if you want) for ~$1300 shipped, and it plugs into your stock wiring harness.
I have had one such setup on my 944 for about 14 months now and am quite pleased with the tunability and ease of use.
You might try contacting RL user "Raceboy" who makes Plug-and-play VEMS setups for all the Porsche models including 928.
Complete stand-alone engine control (every possible parameter, and you can even come up with new ones if you want) for ~$1300 shipped, and it plugs into your stock wiring harness.
I have had one such setup on my 944 for about 14 months now and am quite pleased with the tunability and ease of use.
Intriguing. Thank you, I will reach out and learn more.
I thought I would post this here given it's related to sorting my troubled turbo. Pulled the LZF and LH computers and was going to put the tuned chips in from Pele. During the pull found more shoddy wiring I'll have to sort. I also need someone look at the computer photos and let me know if they see anything out of place. I thought the replacement chips would need to be pushed into a socket of sorts. Will I need to de solder and re-solder? I, so I'm in trouble and I'll have to take it to someone as my soldering skills suck.
It does look like someone tried to de-solder the back of that board, but the two top views seem to show it's in a carrier, so that was likely a mistake. If it is in a carrier (as it should be) you should be able to remove it by carefully prying it out from alternating ends with a small screw driver or plastic probe (plastic might be better). It's best to ground yourself and the board while doing that.
If you really do need to de-solder the chip, get a solder sucker (they're cheap tools that pull liquified solder off the board. See http://www.digikey.com/product-detai...zRMBoCsHbw_wcB). It's not very hard to do. You just get the solder hot with a good quality gun type soldering iron, and then hit the button on the solder sucker to pull off the molten solder.
You might try contacting RL user "Raceboy" who makes Plug-and-play VEMS setups for all the Porsche models including 928.
Complete stand-alone engine control (every possible parameter, and you can even come up with new ones if you want) for ~$1300 shipped, and it plugs into your stock wiring harness.
I have had one such setup on my 944 for about 14 months now and am quite pleased with the tunability and ease of use.
Charles, the only EMS with a proven track record for 928 tuning is the Sharktuner!
FYI. Rocket has been boosted 12 yrs and no knock sensors installed. I run a constant-3 timing and absolutely no issues at 10-12lbs boost. Idle through WOT are spot on
I believe Inter-cooling is the key to help prevent detonation.
thanks cpayne. I think I vaguely remember seeing something about this a few years back, but my memory is a little fuzzy, to say the least. Very interesting info. Was somewhat surprised that it's Hungarian. Has anyone actually used this system on a 928?
I've been using VEMS on 928s for years. It is a great board.
The biggest issue is building a new harness. I personally want a completely new engine harness, switch to a more modern ignition system when I do it.
04-03-2017, 03:03 PM
