VEMS Plug-n-Play - quick review

[v2rocket_aka944]

Several people asked me to share my impressions and experiences with the VEMS setup once I got it installed.

I have been running it for a few weeks now, and all is good.
Installation is very easy, because of course it is plug-and-play
Hardest part was adding the 2-wire ISV to my early car (which has no such provisions).

I mounted the IAT sensor on the top half of the factory airbox, and put together a "delete pipe" to connect the airbox straight to the J-boot since the AFM is no longer needed.

Everything else plugged in to place. Took a little bit of tweaking on the initial setup file but once the car started, it runs great. VEMS has a "fuel pump prime" option which runs the pump for half a second or so when you first key-on..I like that, makes the car start faster after sitting for a few days and will help in the future diagnose a bad DME relay.

Driving around the car feels great, and with an open intake tract letting the engine breathe, the exhaust note even changed and got crisper (more machine-gun sound at WOT). And the Auto-Tune feature (the reason I bought VEMS in the first place)...my goodness, it works well.

VEMS-Tune software is easy to use and mostly self-explanatory - I am not a computer person so the terms and stuff used make no sense to me (baudrate??) but in terms of adjusting numbers it is easy

Peep (Raceboy here) is very helpful with getting it set up and coaching through the installation process.

Overall very pleased with it so far, well worth the $1200 or whatever I paid (more than I paid for the 944 originally!)

I intend to take the car back to the dyno sometime soon, and do back-to-back comparisons with/without the AFM installed, to illustrate definitively the restriction posed by the flapper door.

[944tothefloor]

Niiiiice. Can't wait to see some dyno results. Seems like you feel a lot more power though? Nice review.

[smudo]

Another nice feature is that you can use many modern injectors as you are nor any more restricted to certain range ohms (which are not available for modern injectors). But still the best feature still is that you can make improvements to the engine and auto-tune will adjust to it.

[fiily]

Spencer,

How would you rate this compared to the Rogue NA tune you had on the vehicle? Good , bad, indifferent?

Thanks

[GostRidr]

I have no idea what this is but it sounds too insane to not look up right away. This is from VEMS.us but it was last updated in 2010.

VEMS US | Versatile Engine Management Systems

Did you buy direct from them or does the term Versatile Engine Management System cross over to lots of manufacturers? Would your basic system grow with your car if you then transferred it to your 968 turbo dream build?

Thanks for sharing. I look forward to learning more!

[v2rocket_aka944]

VEMS is a particular type of universal standalone ECU.
There is a fellow in Europe who takes the standard "build it yourself" ECU and configures it so that it plugs directly into the 944 engine harness, and has a tune onboard for the 944 engine to get you going. I bought the kit from that fellow.

From there you are free to tweak it as you wish...boost, variable cam timing, NOS, anything you want it to do, it can do.

filly:
I really liked the NA tune but I just didn't have time/interest to log it and tune the AFRs to be spot-on.
Nothing wrong with the setup, it got my early NA rated 143hp at the crank up to 160 with lots of dyno tuning. It was just my personal reality.

The option of having an auto-tuning feature, with an ECU that understands wideband input and that also is NOT 30+ years old, was very attractive and was why I went for it.

[Das944]

Thanks for posting the review. I'd like to try a standalone control system on my early NA. It seems VEMS or Megasquirt are the best choices. I just read some of the info on the Internet, and I can't believe the features these things offer.

[sausagehacker]

Augtronic is cool too, it's plug and play. I'm really happy with megasquirt on mine. Standalone is great if your car is modified or you have plans to modify more in the future.

[Raceboy]

Thanks for the positive review Spencer! The fiddling with initial tune was my fault: the tune for NA came from a car that had different injector output enabled for injectors 3+4 and obviously it did not work for Spencer's car. After I changed that in the file, he uploaded it and car ran like it should.

I offer Plug and Play VEMS units for many Porsches. So far I have made kits for 944 NA, 944 Turbo, 944 S, 944 S2, 968, 911 3.2, 964, 993 (both normal and VRAM engines). Also many non-Porsche models.
I build the VEMS ECU from parts I buy directly from factory and fabricate the adapter harness (or configure VEMS with Motronic connector if customer wishes so).

Note that it is one of the very few ECU's that can easily utilise factory speed and ref sensors, no need to fabricate a trigger wheel or something.

Note that you can also use the VEMS unit on some other car as well, only need a harness adapter for that. It supports two complete configs in the ECU, not just table switching.

[smudo]

Today received from Raceboy my 951 VEMS together with Siemens Deka 630 cc injectors.

[Jay Wellwood]

Im interested in your results smudo.

[smudo]

I am doing engine rebuild. Should have it together in a month or two. Will to the dyno and fine tuning in summer. More or less stock 951 engine, except: wossner rods, APR head bolts, rebuilt and re-balanced k26/6 with bullsey drop in wheel on the cold side and slightly bigger hot side (lighter shaft and bigger 54mm rotor compared to 48mm OEM one), 3 inch cat less exhaust, tial 38mm WG, will retain the OEM airbox, AFM will be replaced with straight pipe, Siemens deka 630cc injectors, windage ports in the block, running pump fuel at around 16 - 17 psi. Will post the results in July.

[Das944]

Will someone please list the changes and items required for the plug-and play installation on an early NA 944?

Required: (?)
Throttle position sensor
Intake manifold pressure sensor
Intake air temp sensor
Oxygen sensor on the exhaust
Some sort of crank-position sensor

Optional: (?)
Fuel pressure sensor

What is included it the basic pnp kit?

Jeff

[v2rocket_aka944]

Originally Posted by Das944

Required:
Throttle position sensor (direct replacement for stock one)
Intake manifold pressure sensor (built into the ECU - you just run a vacuum line into the cabin, from the manifold)
Intake air temp sensor (i mounted mine on the air filter box lid)
(Wide-band) Oxygen sensor on the exhaust (direct replacement for stock one)
---2-wire Bosch Idle stabilizer valve...a 944S one will work, or the one off of 80s/90s Volvo cars.

see above

the PNP kit came with the ECU, IAT sensor, and some wiring to connect the TPS to the DME harness, and one to connect the IAT to the AFM plug.

you still need to buy your own Wideband sensor and wiring, but it plugs directly into the ECU.

if you had everything ready to go, you could do the install in an hour or so...

[Rasta Monsta]

Hmmm, where's that troll from the other thread now?

Good job, Raceboy.

[Das944]

Does the O2 sensor require a controller? I think the megasquirt system requires the O2 sensor to have some sort of controller ($150?).

[v2rocket_aka944]

No, the Wideband plugs directly into the ECU.
The VEMS ECU understands wideband sensor output.

[Das944]

Thanks V2. I think the pnp VEMS looks like the best deal. I could see buying a non-pnp and wiring everything myself, but having a base tune to get the car running might very well be worth the difference in cost.

[sausagehacker]

Originally Posted by Das944

Thanks V2. I think the pnp VEMS looks like the best deal. I could see buying a non-pnp and wiring everything myself, but having a base tune to get the car running might very well be worth the difference in cost.

If installation and setup time is a concern, VEMS is a no-brainer.

(in general) I have a ton of Megasquirt base tunes for 8v, 16v, and turbo cars. If that makes anyone conversion more straightforward, shoot me a PM and I'll dig around. Setting up a base tune is actually a lot easier than it sounds....it just has to keep the car running while you tweak it.

[running_cold924]

Spencer - quick question, how did you route the plug for the wideband? since the VEMS ecu sits in the same spot as the original one did how did you go about the connector for the O2? Back up through the firewall and out or did you make a hole inside the car to route the plug down through?