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I have a fairly stock 1986 944 Turbo which I purchased early 2015. I’ve since had the turbo rebuilt, replaced a lot of the hoses, seals and bushings. (Intro thread here: https://rennlist.com/forums/924-931-...944-turbo.html) The car has been mostly sitting the past few years as I’ve been trying to hunt down the cause of bad idling.The current shop is found bad crank sensors and I’m hoping that finally solves it.
Nonetheless, I’m looking to replace the DME. I’ve been doing some reading up on these board and it seems my two best options are to upgrade to an FTech9 DME or get one from VEMS. I *don’t think* I’ll be modding the car much, maybe just some bolt ons. I’ll definitely upgrade my suspension, probably to a Motion Control Suspension (MCS) 1WNR. The car is currently on 7 and 8 x 16” Fuchs and it will be needing new tires.
The plan is to keep things mostly stock other than upgraded suspension and good tires. The rest will depend on how much fun it is on track and whether I want to go down that road with the 944 Turbo. I do have other cars that I regularly track so I’ll probably keep it fairly stock. The on,y thing I’m considering at the moment is a Rogue M tune as it’s easily reversible.
Having said all that, I was wondering if I’ll be better of getting the FTech9 DME or spend about twice the money for a VEMS kit. In the case of the VEMS kit, I understand the main advantage is the lack of need to upgrade chips as the VEMS kit can autotune. Is the VEMS kit truly plug and play? Is there any sort of configuration required? I’m afraid something might go BOOM if I (or anybody local with no experience with VEMS) need to muck around with tables and such.
I’d appreciate feedback from those with experience with either or both.
I think what you are really contemplating is VEMS vs stock setup: my understanding is that the DME isn't so much a performance upgrade but rather a modern direct-replacement, therefore eliminating any issues re: troubleshooting etc.
Subbing an FTech9 DME simply helps ensure the stock system is running as it should.
Since the VEMS uses a completely different ignition setup, you are comparing an older system (distributer, etc) with something more modern. Clearly, there are advantages to modern systems.
But sticking with stock does offer more combined experience from users to draw from. Much easier to pop in a chip even with the MAF setups out there... lots of history!
I think what you are really contemplating is VEMS vs stock setup: my understanding is that the DME isn't so much a performance upgrade but rather a modern direct-replacement, therefore eliminating any issues re: troubleshooting etc.
Subbing an FTech9 DME simply helps ensure the stock system is running as it should.
Since the VEMS uses a completely different ignition setup, you are comparing an older system (distributer, etc) with something more modern. Clearly, there are advantages to modern systems.
But sticking with stock does offer more combined experience from users to draw from. Much easier to pop in a chip even with the MAF setups out there... lots of history!
Yes, I understand that. I was basically debating whether to just update my DME with a more modern unit or go with VEMS. Having read though the various VEMS threads, I’m unsure if the added complexity of the VEMS is worthwhile for my purposes, especially if I currently am not contemplating any extensive engine mods. At most intake and exhaust.
The one upside of the VEMS though is I undertsamd it makes the engine breathe better. So I guess the better comparison would be FTech9 plus Rogue M tune vs VEMS....
Yes, I understand that. I was basically debating whether to just update my DME with a more modern unit or go with VEMS. Having read though the various VEMS threads, I’m unsure if the added complexity of the VEMS is worthwhile for my purposes, especially if I currently am not contemplating any extensive engine mods. At most intake and exhaust.
The one upside of the VEMS though is I undertsand it makes the engine breathe better. So I guess the better comparison would be FTech9 plus Rogue M tune vs VEMS....
However you are not sure if there is anything wrong with your current DME. If there isn't, then the FTech will have no return at all on your investment except having a backup DME.
If you are considering MTune than VEMs maybe better value with more potential for the future.
With VEMS I think you will have a more enjoyable car to drive even with no engine mods. The cost is a little tinkering. Whether that is a positive or negative is personal preference. You can always revert back to stock with VEMs and recover some of your costs.
VEMS can be used with stock ignition system (coil+dizzy+rotor) OR whatever other setup you might want.
Oh interesting.. I didn't know that. If you're not modernizing the ignition, what would be the advantage to VEMS, other than the ability to tune yourself (a bonus or minus, depending how well or poorly you do so lol)?
the ability to tune is a big one. brand-new ECU hardware is another (no 35 year old dry capacitors and obsolete chips, etc).
the big one is the MAP conversion, deleting the AFM - you'll finally be letting the engine breathe...you'll have big gains in driveability and low/mid-range torque just by removing the "straw" from the system.
back to back driving an AFM car to a MAP (or even MAF) car, even with similar tunes, feels like the AFM car has a parachute on the back.
Oh interesting.. I didn't know that. If you're not modernizing the ignition, what would be the advantage to VEMS, other than the ability to tune yourself (a bonus or minus, depending how well or poorly you do so lol)?
You can still advance the timing with a standalone with the stock dizzy. Peep told me wasted spark is not needed until you are approaching 400hp.
I see.... though you can run a MAF with a new DME and get much of the benefit except you're stuck with someone's tune, correct?
It's just that the existing M-tune and Vitesse tune (maybe others) seem like pretty good & time-tested setups; not sure I'd trust my fiddling in comparison lol
I'm in the same boat really. I keep fighting the urge to "wake up" this puppy, and we all know the 951 is capable of much more than Porsche allowed at the factory. I understand that "limiting" it leads to a more reliable overall experience. When your not pushing the edge, things last longer. For that reason, and also an interest in keeping it stock for collector reasons, I've held off.
But M tune and VEMS does interest me. As long as I can return it to stock if I ever sell it, then it's on the table. I just worry about overtaxing the engine. Blowing gaskets, excessive wear and tear, etc.
And since I have an 86, there's the DME conversion to 28 pin needed for M Tune. That bothers me a bit. Guess I could just buy a spare DME and convert it, and keep my original if I want take it back to stock.
But it's all just dreams for now, lots of other things to address before I get to mods of any kind.
Collector reasons? I take it you don't plan to drive it much then? Shame; even stock the car makes a nice commuter
I too like the "stock look" and feel but man, nothing right about original stuff when it's so old and worn. Maintaining with modern pieces can give reliability and drivability both a boost.
I drove a '69 VW Bug for a while then a restored '60 for 10 years; no ignition points in either--replaced with discreet hall-effect pickup.. plus a period-correct Bosch "mechanical advance" distributer. Much better performance + reliability! And still stock-looking.
I'm a fan of the Vitesse "stealth" MAF.. check it out. Even better is one guy around here actually managed an MAF built INTO the stock AFM!
At this point I have tried most everything including having a FTech9 DME (very nice), multiple chipsets, Rogue M-Tune, Vitesse MAF, VEMS and the only thing I would ever run on my car is Vitesse MAF or VEMS. My car (now that its tuned) starts like a Honda on VEMS and is very drivable. It was easy to install and setup but I am no tuner so it wasn't that great until it was "dialed in". I still feel the standard issue timing map that came loaded on the Vitesse is better than what a tuner dialed my VEMS in on a dyno. Thats fixable of course but out of the box Vitesse just works w/o messing with anything. I like that VEMS is totally reversible and I was able to undo all the hacked in wiring I had with wideband sensors / piggybacks etc - back to a stock/clean wiring harness...and the fact that when my new motor goes in the hardware wont need to change at all, just needs to be re-tuned.
I'm a huge advocate of standalones but unless you are geared up to learn basic tuning and do it yourself (or pay someone) you are barking up the wrong tree. VEMS has a decent enough base tune but it's there to be safe until you dial it in for your specific car, not as a clone of a stock/daily tune.
At this point I have tried most everything including having a FTech9 DME (very nice), multiple chipsets, Rogue M-Tune, Vitesse MAF, VEMS and the only thing I would ever run on my car is Vitesse MAF or VEMS. My car (now that its tuned) starts like a Honda on VEMS and is very drivable. It was easy to install and setup but I am no tuner so it wasn't that great until it was "dialed in". I still feel the standard issue timing map that came loaded on the Vitesse is better than what a tuner dialed my VEMS in on a dyno. Thats fixable of course but out of the box Vitesse just works w/o messing with anything. I like that VEMS is totally reversible and I was able to undo all the hacked in wiring I had with wideband sensors / piggybacks etc - back to a stock/clean wiring harness...and the fact that when my new motor goes in the hardware wont need to change at all, just needs to be re-tuned.
10-25-2018, 07:03 AM
VEMS vs FTech9 ECU
