Steve Weiner-Rennsport Systems

FWIW,.....there is about a 25 lb-ft torque difference between the non-Varioram engines and the Varioram ones between 3000 and 5000 RPM.

I can close the gap somewhat with a good chip, but its a biggie, IMHO,...

Gweedo

Has anybody done this? Any feedback?

Wreck Me Otter

If anyone is interested, I have a complete Varioram intake for sale...

TomF

I sold my v-ram to a RLer that has done several conversions. I can't for the life of me remember his name.

I decided that it wasn't worth the hassle to do. I have driven both, and for around town, I would prefer the v-ram motor, because of the mid-range torque, but otherwise, it is pretty much a wash.

Try searching a bit on Rennlist and on the internet in general and you may find the conversion guy.

Strosek

Does anyone know how to setup a stand alone fuel system (electromotive tec3r) to run a Varioram intake system. I just picked one up and have no idea where to start! I used the tec3 with the 95 standard black ABS intake that has a single switch to open the bottom tube and had no problem with that but I have no idea about the Varioram. Also if I could see what the plumbing looks like and vacuum tube routing was that might be a start. I'm sure someone out there knows I just need that persons help...

Thanks

NineMeister

Setting up the Varioram using an aftermarket ecu is no more complicated than the earlier resonance tube manifold, except that you have two solenoids to control the resonance flap and the varioram tubes.

I cannot speak for your electromotive system as I have not used it, but I would guess that it is similar to the Motec systems we use. What you need are two switched load/rpm (or rpm only) outputs to actuate the solenoids. From memory the varioram tubes switch first at 5100rpm and the resonance flap switches second around 5900rpm, but that said ideally you should play with these switch points on a dyno to find the perfect compromise.

The vacuum system is simple enough, you need to retain the vacuum canister and have a one-way valve between it and the manifold take-off, then tee off the vac pipes to the inlet port of both solenoids. The outlet port of the solenoids then go to the actuators (diaphragms), the ones visible on the top of the manifold are the varioram actuators which are teed into one valve, the actuator under the manifold is the resonance flap and this goes to the other valve.

If you only have one switched output to play with, simply use one solenoid, connect the output side to all three actuators and hence operate the flap and tubes at the same time, pick somewhere around 5500rpm to start with and experiment between 5000 & 6000 on the dyno.

993Porsche

Does anyone have a picture diagram of how it's put together or works. Just some kind of visual.

Thanks,

KrS

Strosek

A diagram really would be helpful... Anyone? I need help with the connections on the far left side, it's very different then the plastic intake.

Thanks

Bill Verburg

Steve Timmins has a description w/ pics and dyno comparisons here Most of the pics don't seem to be coming up currently

Further Amplification from the 993RS Technical Manual



A) Vibrating tube induction

If the gap (5) between sliding section (4) and central
intake distributor (6) is closed, the intake system is a
single-chamber vibrating tube induction system. Intake
air flows from the central intake distributor via vibrating
tubes designed for maximum torque to the cylinders.

B) Resonance induction

If the sliding sections (4) open, switching the system
from vibrating tube to resonance induction, the air flow
branches downstream from the air mass sensor (1).
One branch is connected to the central intake distributor
(6) of the single-chambersystem and one to the resonance
system (7) below the intake distributor.

From the central intake distributor, part of the intake air
flows through the intake pipe extensions, which act as
resonance tubes, directly to the intake funnels of the
short vibrating tubes and to the cylinders. The main intake
air stream flows via the second throttle flap and
the first large resonance tube of the resonance system
(7) to the resonance chambers. The resonance induction
system optimizes air flow to the short vibrating tubes.

C) Resonance induction with open tuning flap

The tuning flap (3) is installed in the second large resonance
tube. Initially, the tuning flap is closed. At a defined
enginespeed (5920 rpm), the tuning flap is opened,
increasing the flow area between the resonance chambers.
Air now flows to the resonance chambers via all
the connecting pipes.

Switch over conditions for intake pipe extensions
and tuning flap

1. When the ignition is switched on, the DME control
unit activates the solenoid valves. If the engine is
started, the intake pipe extensions and the tuning flap
are operated. When the engine has run up to idle
speed, the signal to the solenoid valves is deactivated
and the intake pipe extensions and tuning flap
are set to their basic positions.
2. If the engine speed reaches 5160 rpm and the
throttle valve is at least 50° open, the DME control
unit transmits an electrical signal to the solenoid
valves of the intake pipe extensions and the extensions
are operated, switching the intake system over
from vibrating tube to resonance induction.
3. If the engine speed is higher than 5920 rpm and the
throttle valve is more than 50° open, the DME control
unit opens the tuning flap, increasing the resonance
tube cross section.

North Coast Cab

Back to the ECU. Is there an alternative, chip reflash etc. versus changing the ECU? Also, can someone provide the desired ECU part number? Assuming thta is the way to go, is it still an OBDI set-up? If so, is chip reflash desirable?
I really don't know what I'm talking abou here, but I have the intake and airbox already and really just need a few small parts and the ECU sorted to install.

RallyJon

You might look into generic Nitrous or VTEC controllers that take an RPM and/or TPS signal. Check out the MSD products, esp the new 8940.

Bill Verburg

As long as you have the 55pin '95 DME and the update harness, all you need is a chip and to connect the right wires at the engine.

RallyJon

Can you clarify which DME and chip will work? Is the code for the VRAM control already there, and just needs to be unlocked or what?

I have a '95 with immobilizer and it took two tries and a custom flash from GIAC to even get a chip working with my DME. I think there must be different versions of the OBD-I DME.

Bill Verburg

all of the necessary code is in the chip. The DME just provides support electronics.

You have the same DME as I do, I just popped in the chip burned when the engine was in the '76 chassis, the main 55 pin harness is the same and the engine harness(changed under a factry recall) just needs the leads for the vram connection

North Coast Cab

Bill,
Are you saying you don't need the secondary air pump or vacuum reservoir? They are about $500 used from DC Auto or $1000 new from the dealer. Cruise bracket shoudl be easy to modify so I'm not worried about that.

Sure would like to hear from someone who has actually done this!