3.6 964 ->3.6 964 w/Varioram Intake

[CBRacerX]

Greetings,

I've done a search and came up dry, so I'm asking:

Has anyone taken a 964 Engine and installed a varioram intake without doing a complete electronics upgrade to 993 harness, etc?

Yes, I'm trying to do this and wanted to see if I was a pioneer or not (and perhaps glean some valuable advice!).

Thanks,

Chris Brown
87 Coupe soon with 964 and Varioram Intake

[ChrisBennet]

Did you check Steve Timmin's web site? He mentions doing the conversion.
EDIT: Here's a link to How and why a VarioRAM works on Steve's InstantG web site.

"What is the result - the VarioRAM is rated at 10 more HP than the stock 993. This is because of the valve size alone. VarioRAM engine intake/exhaust valve size is 50mm/43.5mm vs 49mm/41.5mm. This has nothing to do with the VarioRAM."

Sound to me like a VarioRam would get you nothing more at the top end.
-Chris

[Bill Verburg]

Steve has done that type of thing, give him a call.

[Mike Feinstein]

Low end torque is a thing of beauty.....not to be underestimated...

[CBRacerX]

Steve T. is a friend and he is assisting me with this conversion. However, I also like to gather as much information as possible from as many sources as possible when going off the beaten path on things mechanical or otherwise.

So how about it, anyone given this a try?

Chris

[CBRacerX]

In a effort to flush out those folks that might have some experiences to relate, here is the plan 'so far' on this project:

1990 964 Engine (no head to cylinder leaks obvious) basic 'long block' with 1990 heat exchangers and cat, O2 sensor. Custom single outlet muffler in factory location. 1990 964 wiring harness and DME, with Cyntex programming as needed.

1996 Varioram Intake, with injectors and fuel rails. 1990 "flapper box" mated to this for purposes of fuel metering.

RPM Activated switch for Varioram.

So far:







One of my questions in this circumstance is the closed and full throttle microswitches found on the 964 throttle body - the 993 uses a TPS, and the install of the microswitches looks a bit challenging. Be a lot better to use the TPS somehow.

Another is the oil line to use from the scavenge side of the system. I think a factory line would be a good starting point, since I have a G50 in the car.


One way or the other, this is going to be running soon, I have been waiting too long without any real progress, and the wife wants to get back on the track.

Cheers,

Chris

[tholyoak]

Couple of thoughts:

I had a pre-varioram 993 throttle body on my 90 3.6, if the throttle body on the vario is similar the attachement of the throttle switches isn't too hard. I actually still have the setup if you are interested I can take some photos of it.

On the actuation of the varioram, could you not use the signal from the 964 that actuates the resonance plate solenoid and use it stock or modify the chip so that the solenoid is energized when you want it? Don't know when the varioram is activated but I believe the resonance plate is opened at WOT and over 5k.

Todd

[CBRacerX]

Todd,

Thanks for the suggestions. I'd love to see some pics of your throttle body setup.

I do think it would be possible to use the 964 Resonance Flap signal to trigger the Varioram. I'll speak with Paul at Cyntex about it when I get a little closer. Perhaps I will set up the signal for this from the harness to make it 'plug and play' while I am on the Dyno.

Thanks again!

Chris

[KobaltBlau]

Originally posted by CBRacerX

One of my questions in this circumstance is the closed and full throttle microswitches found on the 964 throttle body - the 993 uses a TPS, and the install of the microswitches looks a bit challenging. Be a lot better to use the TPS somehow.

What are you using to trigger the varioram? a "vtec controller?"

I have not done this conversion, so take my advice with a grain of salt. Normally if an ECU is set up for closed/full switches versus TPS that is a big difference. I think your options here are:

1. rig the microswitches and use the C2 ECU
2. use a 993 vram ECU, might have incompatibilities with other sensors you have, and OBDII PITA unless it's a euro ECU
3. programmable engine management (like megasquirt on the cheap side, motec on the expensive side)
4. build some electronics that convert the TPS signal into equivalent closed/full microswitch signals. This is a pretty simple electronics project, but an EE would be handy. I don't know of anyone who makes this off the shelf.

[CBRacerX]

Andy,

Good thoughts all. Right now I am going to take a detailed look at #1 courtesy of Todd, and #2 courtesy of RedNine. #3 I am going to pass on, but it is a thought (I did a TEC once, never again..). #4 is where I was leaning - given the right help it should work nicely.

Cheers,

Chris

[tholyoak]

Chris

I'll get a photo of it tonight, drop me your email address at holyoak@brandeis.edu and I will send it to you.

Todd

[tholyoak]

Chris

Here is how I adapted the microswitches to the 993 throttle body.

Here is the 993 TB with the TPS removed and the 964 microswitches mounted



The mounting bracket was cut and trimmed such that the idle contact is to the right and the full throttle contact is at the top.


This is what was used as the cam to actuate the switches,




it was taken from a 944 throttle switch (what is insided if you pop it open, and actuates the microswitches in that application. The plastic cam actuates the full throttle contact while the metal extension actuates the idle contact. You can't simply use the 944 switch as the throttle opens in the opposite direction.

Here is everything mounted,



Not the prettiest but worked just fine. I believe a simpler option would be to use a throttle switch from a 3.2 Carrera as the throttle should open in the correct direction, but I wanted to use what I had on hand.

Todd

[KobaltBlau]

Nice work, Todd. That looks like the easiest option to me (maybe easier with the C3.2 parts, as you noted).

[CBRacerX]

Todd,

Thanks very much for the detail. The '96 varioram throttle body is a bit different but your approach could probably still work with it.

I've decided that the path of least resistance (and most likelyhood of success) is the use of a Euro 993 DME and DME Harness. I found a good source for this at a reasonable price and that is the plan for now. I'll update when these parts are in my hands and I make 'em work.

Chris

[KobaltBlau]

You sure all the sensors are the same? (like O2, temp sensors, etc...)

[CBRacerX]

Good question.

I'll have to change the knock sensors (I got most of the sensors included with my 993 Intake/Harness/DME purchase, including these). The crank sensor is a ? at the moment, the O2 Sensor is a single on on the Euro 993 so that should be OK.

But I need to look at this carefully. Fortunately, I have a '96 here at home that I can examine in detail (at least as much as I can see with the engine in the car!).

Chris

[KobaltBlau]

OK, sounds like you are on it. I have no clue how much these sensors vary, but of course if the output on one of the sensors was wrong for the euro DME the engine might run like crap (or not at all).

[Moses]

My varioram kicks in at 5,400 RPM and 3/4 throttle. You can feel it. While it's nice, it's not like going into warpspeed. I'm not sure I would go to the trouble to add it to a non V-ram motor.

[KobaltBlau]

Yeah, but it's giving you more torque than a non-vram manifold before it "kicks in".

That said, I don't know if I'd add it to a non-vram motor either. I do agree that a dual stage intake manifold is no hyperdrive.

[CBRacerX]

But when a cheap 'complete' VarioRam setup comes your way, and you like challenges and doing something a little special, and you have less $ in the 3.6 than most would - I seems like a good idea!

Plus, the 1990 Intake was dirty.

Then again, I have built about 8 personal porsches so far (track cars, PCA racing cars, street monsters), two of which were 944 Turbos (shudder).

I should know better...


Chris