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Discussion Starter · #1 ·
Long before the CIS FI systems

Long before the CIS FI systems used on all Ferraris from 1980 to 89 came along there were very efficient FI systems widely in use. In fact the CIS Injection Systems were/are a huge step backwards as far as performance is concerned.

In days gone by (and agian starting in 95 for Ferrari) every Builder/Tuner worth a hoot used an Individual Runner (Intake) with it's own Butterfly and Injector to deliver the air and fuel needs. There were several ways to deliver the High Pressure Fuel, Mechaincal Timed Pump being the most familiar from FI, Can Am, the Famous Porsche 911 RS, etc. But in all cases the air was delivered via Seperate Intake Runner and Velocity Stack with it's own Butterfly. This set-up allowed unrestricked Air Flow at ALL RPM's and the metering of Fuel for Maximum Power.

Along came emmisions rules and Many Manufacturers like Ferrari & Porsche struggled to move into the modern world of Performance and Low Emmisions. Along came Bosch with a system (CIS) that Metered Fuel Flow Precisely while Restricting Air Flow to achieve an A?F Ratio that could be fed through a Catylitic Converter without causing fires. This was great on the emissions front but disaterous on the HP front. The 308 engine for example dropped from 235 HP with webers to a paltry 205 with CIS Injection. Not good said the racer types.

As technolgy advanced (mainly the speed of electronics) Ferrari once again in 95 returned to Individual Throttle Bodies on the 355. Horsepower thru better Flow was back on the map.

As many of you know an engine is simply a large Air Pump, it makes it's poower from pumping in Air, mixing with a combustable, exploding into power (conversion into heat) and exhausting the mix. It was found that even that waste product could in turn be used to provide additional power thru Turbo Charging. Not the subject of this thread, however. But that use of waste gas had drawbacks in the additional Heat & Stresses it created.

Now many are wondering how to increase the power of their stock Ferrari engines and an exhaust change has become common. Very few however are willing to address the full story of FLOW by removing the Restrictive Intake System dictated by the poor performing CIS System. It has long been known in tuning circles that removing the restrictive CIS System and replacing with Individual Throttle Bodies would truly deal with the Flow issues and unleash tremendous potential from the otherwise choked off base engine. The problem has been cost and the complicated series of changes neccesary coupled with the PR generated from Turbo Charger Kit sales people. As history has played out and the Turbo Kits have proved to be engine killing money pits that generally have questionable performance gains, the Indivisual Throttle Body Concept is gaining more popularity.


Discussion Starter · #2 ·
Here are a couple of pics of I

Here are a couple of pics of ITB's on a 308 set-up. Notice Air Flow is completely unrestricted.

Pictures courtesy of TWM Induction.

Discussion Starter · #3 ·
Ferrari F1 engine with ITB&#39

Ferrari F1 engine with ITB's and Injectors that simply spray directly above & into the port.


Discussion Starter · #4 ·
JRV...Have you ever used the T

JRV...Have you ever used the TWM injection on a car? My engine is in peices right now doing a rebuild. Now would be the time for me to figure this out if i want to do something like this. The CIS system is terriable for air resrtiction as you said. If I were to replace it with this system what kind of horsepower increase to do think it would produce? Do you think 15 to 20 horse is over the top? Also throttle response is a big issue for me aswell. The 308s are lazy when it comes to this. I would like my car to respond much more quickly the it does to "blips" on the throttle. Any info that you could provide would be appreciated.

Discussion Starter · #5 ·
Early to tell right now, but b

Early to tell right now, but based on early dyno numbers, even replacing my Kjet with 40 dcnf Webers (individual throttle bodies) is looking like about at least 15 - 20 hp gain. Already the throttle response is amazingly better than the Kjet. I think 20+ hp with individual twm tb's is a safe bet.

Of course, we need to mention that converting from Kjet opens the door to far more aggressive cams and timing than the pulsing restricted Kjet cams. With cams and individual tbs, 90+ hp/liter should be attainable, especially in 4v cars.

Discussion Starter · #6 ·
JRV I am interested in source

JRV I am interested in source for an ITB setup f ro my TR. Part of the TT mod I am considereing includes the use of a Motronic FI system. THis sytem still utilized the original intake that is modified for electronic injectors.
Is there a "bolt on" for a TR in regards to ITB and eletronic FI system available? Or are all coustom made? Also, if you are a builder that can supply such a system I would be interested.
Contact me offline
[email protected]

Discussion Starter · #7 ·
>>Of course, we need t

>>Of course, we need to mention that converting from Kjet opens the door to far more aggressive cams and timing than the pulsing restricted Kjet cams. With cams and individual tbs, 90+ hp/liter should be attainable, especially in 4v cars. <<

Russ is correct.

Russ is also correct that Webers are ITB's in their basic non forced fuel delivery form.


the parts for these ITB set-ups exist, even for 12's, but not in kit form. There are a number of makers of Computers (Motonics) to drive the electronic injectors.

Here is the direct source for ITB Manifold Hardware.

Discussion Starter · #8 ·
One thing owners may want to n

One thing owners may want to note is that the HP drop on the 308 series came in 1978. When Ferrari had to start putting catalytic converters on their US cars, the cams changed as did the idle settings on the engine. It was all set up so that the catlyst would heat up faster, and the cars could pass emmisions idle testing in CA.

Memory says it was the exhaust cam timing which changed and this dropped the HP significanly.

I have a '77 with no cats and the early cams and at least one '79 owner has said my car for sure has more power after we went for a ride. The early 308's had 240BHP and starting in '78, it dropped to 205BHP. I've heard numbers as low as 195BHP for the early injected cars.

Discussion Starter · #9 ·
I just priced the stuff from T

I just priced the stuff from TMW. Geez it aint cheap my friends. All said and done your looking close to 7k. I wonder if it would be possiable to make your own set-up using old carbs,gutting them,and the adding you own injector ports. Shouldn't be that hard!! You could probably peice something to toeghter using G.M. parts and other components I would think. Fuel injection systems are really not that complicated when I comes right down to the nuts and bolts of it. What about using the injection components of say a Corvette of other V8 product out there? Thoughts?

Love Ferrari's cars...Hate the company

Discussion Starter · #10 ·
>>All said and done yo

>>All said and done your looking close to 7k. <<

You'll save that much in gas & spark plugs your first year.

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