No smoke, no mirrors, just fast.
and Warranty Statement
964/993 - 3.6 liter engine conversion kit FAQ
NOTE: Please read the FAQ before calling or e-mailing.
We are more than happy to answer questions, but it gets old when they are
already answered above.
Q: How much HP will the car make? Will I notice
A: Oh yeah! The following are from actual dyno
measurements or porsche data:
Q: How about a 3.0/3.2 conversion for an early car? Isn't
that a lot cheaper and almost as good?
3.0 SC 180-190 HP
3.2 Carrera 217
C2 3.6 with stock chips and exhaust: 247 (porsche, used as
a base line for the following measurements)
C2 3.6 with Cyntex chips 263
C2 3.6, Cyntex chips, B&B Exhaust 272
C2 3.6, Cyntex Chips, McNeil headers, Dual in-dual out muffler
C2 3.6, Cyntex Chips, 1-7/8" headers, dual 2.5" stainless
993 95 Headers, Supertrapps, 289
993 3.6 Varioram , Cyntex Chips optimized for Varioram, Headers,
Supertraps 298, 305 with open exhaust, but read
about the whole VarioRAM story here
A: Cheaper:Yes. Just as good: No. What's better
really depends on your budget.
The 3.0 / 3.2 conversion is substantially less expensive,
and few conversion parts are required if the engine is purchased "complete"
A decent used 3.0 runs about $4,000-4500 and makes 180 to
190 HP depending or year.
A decent 3.2 will run you about $5,500 with DME and makes
217 HP, maybe 235 with better exhaust and a set of chips which can add
substantially to the price.
These engines we now 16 to 26 years old so make sure your
not buying someone else's problems! Look out for broken head studs,
leaky heads and worn out valve guides even a "low mileage" Motors
If you go this way get a 3.2, the extra cost is well worth
it for the engine management alone.
We often have packages available.since we have leftovers
from all the 3.6 conversions!
Q: What are the differences between 993 and 964?
A: There are many differences between 964 engine and
Other then availability of VarioRAM then the easiest approach
is to compare 1992-1994 964 to 993.
Q: What's a VarioRAM and why should I care?
Intake Manifolds: Virually the same. 993 has 1mm larger
runners. Worth 2-3 HP.
Air Flow Meter: the 993 has a mass flow whereas
the 964 has a "barn door" flapper. Worth 2-3 HP
Rockers: The 993 has hydraulic rockers.
They never need to be adjusted and are quite reliable. On the other
hand if the car is a pure race car and spends most of it's life above 5000
RPMs or you ever think of changing to lumpy cams, you'll be better off
with solid lifters.
Exhaust - the 993 has separate right and left exhaust
headers whcih join in the center and a highly efficient dual catalyst.
This is where the bulk of the 25 horsepower change comes from
Crank/Rods - the 993 has a stiffer and lighter crank
assembly (the crank is heavier but it doesn't need a harmonic balancer,
something to think about all those lightweight crankpulley fans).
It also has lighter rods, but narrower rod bearings. Are the narrower
rod bearings a problem? Apparently not since the GT3 uses the same
bearings and crankshaft!
Valves: 993 Varioram engiens (both US and European)
have 50mm intakes and 43.5mm exhausts. All others have the same size
valve as a 3.0/3.2 49mm/41.5mm. This seems to be worth 8-10HP since
at the top end the VRam and 95 993 engines are essentially the same.
A: VarioRAM engines differ from 993 engines in two
1) The intake Manifold is completely
2) The valves are larger.
Intake manifold: Here are pictures of engines with
plastic (95) and varioram (96-98) manifolds:
If you just want the bottom line then the Varioram makes
only 3.5% more peak power. On the other hand it makes 20%
more torque at 4000 RPM!
Explained click here.
Q: Which engine is best? What about 993 Engines?
A: The most popular was the 1991-1994 964, but now
993 enignes are becoming available. Any 3.6 engine can be installed.
It's more important to get a good engine than any specific engine.
There are two basic engien types, 964 and 993. 964 is 1989-1994
and early engines cen be distringished by athe aluminum intake. 993
Engines add hydraulic lifters and a redesigned crank and rods and come
in two basic flavors as well. Click here for full details
Q: What about a 3.8
A: If you have a motor that needs a rebuild then go
for it, otherwise, it's a lot of money.
Q: Can anyone do this, or do I need an expert in 3.6 conversion?
How long will it take?
Displacement means more power. a 3.6 is 76.4x100mm
= 3600 cc. 3.8 is actually 76.4x102mm = 3750 so it's actually
a 3.75 ltr. That's 4%. So let's say you have a varioram and
we say it makes 300HP. Now multiply by 104% and you get 312.
Those can be 12 very expensive horsepower. The Factory 3.8 street
motors, with bigger ports, valves, and intake manifolds were rated at 300
HP, 18 more than the 3.6. The extra 6 HP is attributable to the RS
cams and more aggressive tuning on the chips.
This can get expensive. You can do slip-fit cylinders
($3500 or so), port and modify the heads with larger valves ($1000+), buy
the varioram down tubes and injector stacks ($800), a set of euro RS cams
($800) and pay for a top end rebuild ($2500 -w- machining?) assuming you
have a decent bottom end and you'll be $8500 or so poorer. Ouch.
maybe you get 20 more horsepower. Just slapping in P&Cs is also
a way to go. That's OK if you have to do it anyway, like on an early
964 motor with early P&Cs, but you still have to machine the heads.
We also weld them to strengthen the perimeter.
If you are going to do it right, like a RSR then you need
to do some more things. You have to bore the case 2mm to accept the more
robust cylinders, you need to weld up the heads, and maybe think about
some larger valves. When you hear 375 HP out of the RSR 3.8s then
you are talking much wilder cams, so much so that you cannot use a mass
flow, you do throttle-speed-density like the RSRs did and you are in a
different ball game. 56mm intake valves with 44mm exhausts and some
decent valve springs and retainers. At that point you may as well
call CMW and get their heads and 104mm cylinders and forget about the budget,
you'll be running race gas anyway.
Bottom line: We recommend it only if you are
going to rebuild a motor anyway. While the extra displacement may
not justify it, the extra bragging rights might! We saw abbot 18
HP difference over the 3.6 varioram on an engine that had "warm" hydraulic
cams and RS 51.5mm intake. Those are very expensive ponies considering
the upgrade and rebuild was pushing $10K over the price of a varioram.
Click here for the
truth about 3.8s
A: Anyone competent of engine removal and replacement
can perform this conversion.
Figure on 15-20 hours plus whatever it takes to remove
the 3.6 exhaust.
Q: What other parts do I have to buy?
When I did my first conversion, I was met with nothing but
frustration. The vendor from which I purchased the parts (you can
guess, because he makes the flywheels) was less than helpful. I didn't
know which parts were needed, how to rewire the harness, move the pins
in the connectors, etc. It ended up taking me, who has done a fair
amount of 911 work, over two weeks, and the engine still had problems starting,
fuel leaks, etc.
After consulting with the guys at Cyntex, and
actually taking the car up there, we got all the bugs worked out (you can
get a feeling of this from the notations on the BlauCarrera
page, which was done during the first conversion).
I decided that it would be best not to put the rest of the
911 world through this HELL, so I developed this kit. I got someone
local to make wiring harnesses (since the one I had purchased was assembled
with some pins in the wrong place, which is why the car would not start!)
and decided to offer this kit. Is it a big money maker? No.
Not when you take into account tech support and all the people who pick
my brain then buy the parts somewhere else.
The kit includes COMPLETE instructions and tech support.
Right down to which pins to move in the engine connector to keep from frying
your wiring harness, and five pages of detailed instructions. All
modifications (engine cross member, sheet metal, etc.) are done here at
Instant-G to eliminate any guesswork.
Bottom line: you can do it yourself or have your local
porsche shop to the work. We charge about 20-25 hours on the average
job, which includes cleaning up the 3.6, adjusting the valves, and removing
the exhaust system. Again, a lot depends on the exhaust system chosen.
Some are custom fabricated. If you buy a crate motor, count on 10-15
hours since the hard part is done. We have done conversions in as
little as 6 hours, but I am quite good at it! IF the conversion is
done in house with one of our crate motors in house we generally charge
10-12 hours, more if heating plumbing is required.
A: You must supply the following:
Q:What Exhaust should be used? Can I use SSIs?
How about a Carrera or 993 exhaust?
Clutch, Starter, Starter Ring Gear, throw out bearing, pressure
plate (from existing engine)
EXHAUST - factory 3.6 exhaust WILL NOT bolt in with
late 915! The crossover pipe interferes with the throw out arm.
A: Depends on how much yuo want to spend and how much
power you want to make.
Q: What additional parts are recommended?
SSIs or early heat exchangers are too small. 1-1/2" will
not flow enough at upper revs. 3.6 came with 1-5/8" exhausts form
the factory, which is on the small side (see dyno numbers).
You can use Carrera heat exchangers with 915 but need to
the exhaust studs and fabricate a muffler. Carrera exhaust is
1-5/8 and is roughly equivalent to the C2 exhaust but has a less efficient
catalyst. If you ditch the catalyst you can replace it with a muffler.
We generally stock these systems, and they offer decent value with a small
performance penalty, but are still superior to the stock 964 exhaust system.
You can use the C2 exhaust with a G50 but need to
modify the outlet on the muffler.
If you need heat and a 915, then your only high-performance
choice is B&B. Note: you'll need their 3.6 headers (1-3/4") and
the muffler exhaust tips need to be modified. We are a dealer for
B&B so if you are going that route, let us know. Happy to match
prices but bear in mind that discounts on B&B are thin. Personally
I can't stand the resonance of their mufflers so we have a dual-in dual-out
which we fabricate in house. We use their setup but replace the actual
Headers and supertrapps are most economical, make the most
power, but provide no heat. We use The Racer's Group headers, and
get the Jet Hot coated (see 72 911 project). Package discount available.
See options for pricing.
993 Exhaust: You can not use the complete 993 exhaust as
the mufflers will interfere with the oil tank and rear valance. On
964 motors you have to rotate the 4-6 cylinder exhaust flanges on the headers,
so it's not much fun. You can run the headers and catalysts with
simple exhaust tips should you so desire but it is a bit on the loud side
and you do take a performance hit over headers/B&B because of the smaller
diameter (1-5/8" vs 1-7/8" or 1-3/4")
993 Exhaust on 993 Engines - that works well. You can
modify the catalysts and eliminate the muffler. We generally offer
this option already modified.
A: To make the installation easier, we recommend the
Evo Motorsports Cone Filter $145-185
Spacer Upgrade: $30 This is the upgrade form
a fabricated stack to a stainless steel machined part. Cosmetic?,
Yes, but it makes for a clean install.
Cyntex Chips with idle code, $325/375 with
The factory chips have a fuel cut algorithm to bring the
car down to idle with the massive dual mass flywheel (40 Lbs). When
the factory chips are used with a lightweight flywheel (as supplied), and
especially with a lightweight clutch pack (such as the Sachs Power Kit
clutch pack) the engine has a tendency to stall when dropping down to idle.
The specially designed Cyntex chips have a special idle deceleration
code that eliminates this problem and raises idle to 850 RPM and redline
Cyntex chips also add 15-20 HP depending on exhaust.
Power Steering Housing Block Off $89
Obviously the earlier cars do not need the power steering
pump. Although the bracket will fit in the engine compartment, it
is less than attractive
Cut off the housing (template supplied)
Replace it with a block off.
When the housing is removed, $27 in seals need to be replaced.
We recommend the block off, which eliminates the cam seal and comes with
a replacement factory O-ring.
993 Coil Mount on 993 Engines - clean install, this
bracket is welded to the engine corssmember.
Q: WIll the sheet metal fit or will I need to modify it
Looks cool, flows great, lifetime K&N filter, eliminates
need to hack up air box. Ours comes with the proper bracket.
If you buy it direct form ZucZ you will have to specify parts from several
kits, it will cost the same amount, and it is one more vendor to contact
and pay shipping from.
Single Pulley Alternator conversion? This is
a mixed blessing.
Why? You'll notice a little wheel on a pivot on the
rear belt called a belt minder (one that runs the fan). Porsche
designed these motors so the alternator would spin faster than the fan
because of all the electronic gizmos on the C2/993 motors. They also
designed it so the alternator will spin faster yet on tiptronic cars. This
is a problem though.
The belt minder is set up to trip a light when the fan belt
breaks. On earlier cars, the alternator light came on warning the
driver that the FAN belt had failed. That's nice. Only problem
is that with 2 belts, the alternator will continue to charge even if the
fan belt breaks, and unless you are willing to set up another warning light
on the dash, then you will not know until the motor is cooked!
Also - the wheel on the belt minder has a tendency
to get noisy and stop spinning as the years go by. The pivot also
has a tendency to freeze up, so that even if the minder is attached to
a light, it still wont come on.
The solution is to install a single pulley drive hub.
This will make the alternator light come on should the belt fail, and get
around the belt minder issues. It also has the pleasant effect of
spinning the alternator a bit slower so you gain a little power.
lastly, if you have ever replaced the belts on a 964/993, you know what
a pain it is with two to tension with shims. This makes the whole
Downside: It is a pain the butt to install but other
than that it's the way to go.
Shroud Blockoff and AC Bracket Delete:
If you are not running heat you should block off the alternator shroud
outlet. We make a nice clean inexpensive blockoff plate that comes
complete with a distributor vent kit. As for the AC Bracket
delete, again this is cosmetic, and we have the fixture to perform the
modification. You can also do it yourself, but you'll notice that if you
buy the recommended option kit these two mods are nearly free.
Carbon Fiber Heater Tube $200 - Combine this with
a 993 or other exhaust for a clean install.
A: There are two items, one modifying the sheet metal
so teh engine will fit in the car, and modifying the sheet metal so the
engine compartment will seal.
Q: Where do I get an engine, how much will it cost?
Included in the price of the kit is modification of the
rearmost (nearest the bumper) peice of sheet metal.
Without this modification the engine simply wil not fit.
Beyond that, the 964 sheet metal fits fairly well, with the
exception of the area surrounding the power steering blockoff. You
will need to fabricate this peice. This is performed for customers
on crate motor purchaces at no charge.
On 993 engines, in addition to the power steering blockoff
issue, the sheet metal is too narrow. Again, if this bothers you
then you will need to extend the shet metal. We perform this modification
on engines installed in-house at an additional
A: Junkyards, private parties or from us
Q: What about a Mass Flow unit? Doesn't that make
the 993 engines better? Shouldn't I get that?
A nice C2 3.6 goes for $6800 - $7500. Add a
bit more for a 993 engine. Euro 993 VarioRAM motors may be as much
as $10K used. A bargain may be a bargain, or it maybe a nightmare.
We have seen both. In general reputable outfits (PAP, Partsheaven,
PartsWerks Chicago, DCAutomotive, etc.) sell decent motors with warranties.
Private parties can be a joy or a terror. Know your
source. We have purchased "Low Miles" engines and had them leak oil,
have low compression, etc. Get a description in writing and buy form
a reputable source.
You can get an engine from us. It will come
with the following:
All conversion parts installed and modifications done
Exhaust of choice installed
Leak down Test Performed
Valve adjust performed
Sensors working (you may THINK this is trivial!)
No oil leaks
Engine installed and tested in a car AFTER the conversion
We usually stock one or two engines ready to go of each
type. Expect to pay a bit more but expect to get a true bolt
in engine that will actually run. We spend 10-15 hours on checkout/tuneup,
installation/removal plus parts. This saves an equal amount on your end.
If your time is free it may be less expensive to find your own engine.
You can also send us your complete engine. While we
can give approximate costs actual cost will be determined when the engine
arrives and it's needs determined. This may not be the most economical.
You can have us take care of the whole process.
Drop off your car and we do the conversion. Period. In general
we charge approximately 15 hours for the normal conversion, depending on
A: If you have an unlimited budget, go for it.
If not, think twice.
Q: Which Transmission should I use? Can I use a
915 or do I need a G50
Back to back comparisons of 964 and 911 carrera motors show
that the mass flow is worth at most 2-3 HP. Yes, it's been tried.
It works, but it is not nearly worth the expense.
993 Engines need to have the rockers backdated if used for
prolonged periods at high RPM. THis is enough of a concern that Porsche
Motorsports offers a kit for this that includes 911 rockers and special
shafts. It costs about $800.
The Varioram Works. Period. But the added conversion
costs and the "Black Box" nature of the DME make backdating the engine
management system a viable option.
A: We prefer the 915. For a clutch we use the
Sachs Power Kit.
Q: Can I use my existing 915 clutch? How about a
"Puck Clutch"? What is recommended.
915 is fine up to about 300 HP. Although the
G50 is s stronger box, plan on an additional $4,000-4,500 if you convert
to that as well. That includes $2000 for G50 and rebuild, $2,000
in conversion parts.
A G50 is 100 lbs heavier than a 915. On an average
911 that's like reducing the HP by 3-4%. Remember F=MA?
The choice is up to preference and budget, but the 915s work
A: Yes you can. We advise against it though.
Q: What about oil cooling?
If you know about forces and torques, you know that the clutch
cares abbot torque, not power. The 915 clutch assembly was designed
for relatively low torque engines, like the SC and Carrera. Low power
as well with 180-237 HP. WHen the factory built race motors, such
as the RSR which put out significantly more power, they always used an
uprated clutch, like a "puck style" clutch.
One would think, OK, I'll just get a puck style clutch. Bad
idea for most applications. They operate like an ON/OFF switch. These
put a high impact load on both the engine and the trans, and is a great
way to make the car difficult to drive on the street and ruin your 915.
Also, because they have only 30% of the contact area of a standard clutch,
they tend to wear faster. They are inappropriate for street use.
As a solution, SACHS came out with the "Powerkit".
This clutch solution features a composite/Kevlar segmented (not smooth)
surface, a low-mass aluminum pressure plate assembly for quicker revving,
and has a higher clamping force on the pressure plate. The bottom
line is that they last longer, don't slip and have none of the drawbacks
of racing clutches.
A: You will need a front mounted cooler of some kind.
Q: Can I modify the sheet metal and cross member myself?
Why is this modification important?
For street cars a single Carrera cooler with fan or Modal
fender mounted cooler works fine. The SC cooling loop is not
adequate. The "Brass tube" cooler found in SCs and 1984 carreras
is marginal at best. Pricing is around $300 for SC conversions or $850
for a complete system for an early car.
If the car is to be driven in stop-and-go traffic, it's a
good idea to use a fan on a fender mount cooler.
For cars that will be tracked or used in hot climates, we
recommend dual Carrera or Mocal fender mounted coolers, or a nose
mounted cooler such as Mocal, B&B or Earls. As with everything
else, we can supply this and will certainly match any deal. We also
offer service after the sale (nice when you can't figure out how to do
it!). We have doe pretty much every combination, and you will get
everything from the brackets to the fittings to the adapters. No
A: Yes, you can do that.
Q: How about Webers, aren't they the way to go?
Seems a lot easier and less expensive!
Should you is another question. If you do, do not expect
assistance since walking you through it on the phone is not much fun for
use and defeats part of the purpose of the kit - to remove hassle.
Note theta the kit is discounted nearly $300. This
discount is possible because we cover the 3 hours labor it takes to do
these modifications. Both involve welding. If you choose to waive this
option deduct $100.
The engine cross member should be reinforced. If you
notice rust and/or deformation near the ends it is because the thin material
at the ends is beginning to fail (the engineering term is "stress-corrosion-cracking").
We reinforce this, which is a fairly simple process, but involves fitting
metal and welding the whole thing together.
A: Not easier, not less expensive, but may offer more
top-end power. Upsides and downside below
Q: What about a 915 transmission, will it handle the power?
Are they less expensive? Not really. It ends up
costing about $1500 more for carbs IF you can sell the 3.6 induction or
purchase a motor without it for $1500 less, so plan on spending about $1,400
MORE to go with carbs.
If you use webers, you will need 46 mm. Used they are
$1500, new $3,000. If you get used ones you will need 3 bolt manifolds,
$350 now from PMO, so you are looking at $1850. If you already have
webers, you can most likely sell them, so either way, you are out $1850.
You will also need a TWIN PLUG spark system.
You cannot run "part" of the motronic for the spark, so a logical twin
plug choice is the Electromotive HPV units. The coil packs adn wheel
will run you $950, and add another $450 for a pulley, timing sensor holder,
and distributor plug so you are looking at $1400, plus $300 for a set of
spark plug wires, like from Magnecor, for a total of $1700.
This system will then need to be jetted and tuned so you'll
need new ventures, etc. call this $400.
Total Outlay $3950
What do you save, or can you sell? On a good day you
can get $1500 for the intake, fuel injectors, DME, harness, distributor
and coils. You will not need the conversion harness, chips or 3.6
flywheel, or fuel lines, but you will need an early 3.0 flywheel.
Call is $800 savings, so the total is about $2300. If you think
these numbers are off, then recalculate them. They have to be off
by a lot to make up the $1,400!
What about ease of installation? I'd say it's easier to
install the 3.6 stock induction.
To use the stock system you have to run the DME harness and
hang the coil packs, (two hours), hook up the conversion harness (6 wires,
an hour) and connect the fuel lines. On an early car you have to
replace the fuel pump and run a few more fuel lines, say 2 hours worst
case. Total of 5 hours.
On the Weber side, you need to disassmble the entire induction,
remove the distributor, mount the webers, run fuel lines, synchronize the
linkage, remove the crank pulley, locate the timing sensor, mount the eelectromotive
system, run relays, wire it, replace spark plug wires, etc. Say 10
hours. Then you have to tune it!
I have personally done this. See Teala2001.
It took me 4 hours to convert from a 3.4 with Webers to 3.6, and that included
R&R on the motor, and 2 days to go to electromotive TEC when I went
back tot he 3.4. Absolutely no fun.
Will you get more performance? That is arguable.
Perhaps better throttle response, and maybe a few more horsepower at the
top end. You are likely ot lose power in the low end (torque) and
part throttle response, cold start, and derivability will suffer. Be prepared
to spend time on the Dyno to get the webers right, and expect to retune
them on a regular basis.
What about drivability? No comparison.
Ever get 27 MPG with carbs? That is what we got on a recent trip.
We average 22-24MPG, and that is driving the car fairly hard. The
Motronic system starts when it its cold, idles smoothly, and has tons of
power. I'd never switch to webers, but that is your decision.
A: Yes, as long as it is not abused
Q: What about air conditioning
We have run over two dozen cars without major issue with
The 915 is good for 300 HP in general, and is about
100 lbs lighter than he G50.
The G50 is generally considered a nicer transmission, and
it has few drawbacks other than cost of conversion and weight.
We reccomend the later (75 on) 915 cars with aluminum case
and 8:31, though we have run a few cars with the earlier style transmission.
Reliability will depend on driving style. If you plan
on drag racing, get a corvette. If you are into chirping tires think
again. We have over 4 track years on our 1972 911 with 1984 915,
and the trans is still quite happy.
If you decide that drag racing is for you, get a Chevy.
915 will not handle this, nor will a G50.
A: That's a fair amount of work, difficulty depends
on which motor .
You must use the 964/993 Compressor in all cases. Neither
the S/SC piston type or carrera rotary type will work because of the intake
manifolds. In order to use the 964/993 Compressor you will reed to
have the lines made up or adapted.
If you are converting to a VarioRAM you MUST remove
the deck lid mounted condenser or the deck lid will not close.
The VarioRAM is simply too tall.
NOTE: Please read the FAQ before calling. We
are more than happy to answer questions, but it gets old when they are
already answered above.
302-456-0630 or 302-559-5905