Italian Cars/Italian Cars Digest Archive
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Turbos and Superchargers
>I think of installing either of these two items of a regular basis. I have
>hit a snag on the supercharger. I haven't figured out a way to drive it.
>Everybody I've talked to says it can't be driven by a V-belt. I guess
>because it would slip. Which means I would probably have to change every
>pulley to a serpentine system just for the supercharger.
Have you checked with the supercharger manufactures to see what they suggest? Most of
the current applications I've seen use a multi V-belt. Maybe you could utilize a
crank pulley from a Scorpion, which has a single-V for your water pump and alternator,
but also has a multi-V, originally used for the air conditioner. Or you could use a
cogged pulley like my Volumex has.
>Has anyone seen a Garrett TO3 turbo ? I am wondering if it looks anything
>like the Borg Warner unit used on the "original" turbo Spiders. I'm
>wondering how it would mount up to the exhaust manifold. How would I mount it?
I have a T-3 from a 900 Saab. You should make a custom header to mount it. I bought
an exhaust flange from Stahl Headers, (717)846 1632, and had a custom flange made for
the T-3. Then I bought some Schd 40 weld fittings of various bends to make the header.
>I've heard this is a problem with turbocharged engines. To combat this
>problem on the Turbo Spiders, Legend industries (the company which carried
>out the conversions) used a funky boost setup which basically raised the
>fuel pressure at WOT by means of the throttle positioning switch and the
>coolant temperature sensor. It also used an advance limiter inside the
>I think this setup was rather outrageous and have no plans to track down one
>of these setups.
Actually, what they did was use four Hobbs switches to sense boost at 1 and 5
psi, and to protect the engine from overboost. These were connected in series with the
fuel injection's temperature coolant sensor and at the given psi, would increase the
resistance (1500-2000 ohms at 1 psi and 1750-2750 ohms at 5 psi) thereby fooling the
into richening the mixture. A similar setup is used by Greddy on their supercharged
>I believe modern cars use a knock sensor to control detonation. Does anyone know of
>any "simple" aftermarket knock sensor which fits between the control module and the
A company called J&S Electronics, (714)534-6975, sells a knock control system ($400)
that can retard each cylinder individually. MSD, (915)857-5200, sells their MSD 6 BTU
which allows you to preset from 1 to 3 degrees of retard per pound of boost up to a
maximum of 15 degrees. The J&S system has the advantage of retarding the ignition
only the amount necessary whereas with the MSD, you just arbitrarily set it.
>I think there is enough room to mount an intercooler just before the
>throttle body. Some hood modifications will need to be done for this. That
>is if I can find one thin enough to fit between the hood and camboxes. This
>may come later once I get the turbo setup and working properly.
The intercooler needs to be up in front of the radiator. Otherwise don't bother with
one. The intercooler is nothing more than a radiator for cooling the inlet air from
the turbo to the engine. It needs cool air blowing through it. This will allow you
to run more boost without the knock sensor retarding the ignition as much. Of course
you still have to get more fuel to the engine...
>I assume that the "air" inlet and outlet snouts on the turbo get very hot so
>a common rubber pipe connector from a hardware store will melt. Anyone know
>where I can get these any the piping needed for the ductwork? What are these
>connectors made of?
These hoses are made from silicone and are available from Spearco Performance Products
(818)901-7851. They also manufacture and sell intercoolers.
>On the "original" turbo spiders, a nipple was brazed onto the side of the
>oilpan for the oil return line. Although I am willing to remove the oilpan,
>I am wondering if I could just install one of those filter adapters for an
>oil cooler and plumb the oil that way?
>Is there any harm in doing it this way? I assume that "fresh" oil should
>circulate through the cooler, then to the turbo and then back to the engine.
You would be sending the hot oil from the turbo directly to the engine; not a good
idea. I'd use an adapter to add an oil cooler, which you'll definitely need, and
plumb the turbo like Legend did.
>I wonder how much trash is generated by the turbo. If this might cause the
>engine to wear out faster because it's getting oil first used by the turbo
>before it's filtered.
Older turbos weren't water cooled and had problems with the oil coking. This is
caused by not letting the turbo spool down before turning the engine off. I suggest
you stick with a more modern water cooled turbo.
>As far as I know the original Spiders fuel system was not modified (except
>to prevent detonation) so I assume I that I don't need to raise the fuel
>pressure or get anymore fuel flow when the turbo kicks in. That is if I find
>a knock sensor.
Without more fuel, you won't get more power, just a big paperweight when the engine
detonates. For minimal boost, the methods used by Legend will work fine. For more
power though, you'll need to spend lots of money getting more fuel to the fire.
I think your best bet is to find a Turbo Spider and buy it. That might take the fun
out of it, but it'll save you money in the long run.
Just received my Volumex engine and transmission from England, after waiting 5 months
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