What is best way to retrofit carbs onto GTSi Engine ?

I have a 1982 GTSi and I am tired of fuel injection. weber carbs are readily available but the GTSi intake manifolds are so tall carbs will never fit under the hood.

Has anyone found a successful workaround to just using older GTS manifolds ? that's an options but its' $$$,

any other suggestions appreciated,

thanks

Andrew

 

Search is your friend. Here's an old thread about fitting a QV or 3.2 with carbs

https://www.ferrarichat.com/forum/threads/weber-twm-throttle-body-manifolds-for-qv-3-2.233521/

Good Luck.

 

I have an 89 328 GTS, I like the idea of putting carbs on an injected 3x8, I myself would not want to convert over, I like the injection system, with that being said, I would love to hear what a 328 would sound like after is was converted to carbs !!

Thank you

 

One member here had probably the ONLY Carbbed Mondi 8 in the world.

He switched it over from FI to Carbs.

IT. WAS. A. PROJECT.*

Search that Forum.


He sold it awhile back, but I believe another FChatter bought it.



* - You are not looking at 'Chump-Change.'


On ebay right now are TWO serial number consecutive sets of 4 carbs.

One USED Set(4) and Rebuilt: $5000.00

One NOS Set(4) and never fitted: $10,000.00 (FChatter owned).

And that IS JUST THE 4 CARBS ... NOTHING, AND I MEAN NOTHING ELSE. NO linkage, no manifold, no lines, no fittings, no stacks(trumpets), no airbox, ...

NO NOTHING.


That manifold is very probably the CHEAPEST Part to obtain. The linkages MAY NEED to be made from scratch. IDK but I NEVER RECALL seeing them for sale.

If your pockets are that deep, best of luck. We'd all love to see and HEAR IT.

 

Ya - I saw the set of 4 for 10K on Ebay.

And I know that the linkage will be a bear. Hell - even the stock parts are hard to find. I bought the only set of adjusting links I've ever seen on E-bay, and I'm not selling them.

I agree that you are underestimating how much this will cost or how hard it will be. I'd make a phone call (ya - actually talk to a human) at Pierce Manifolds in California. They rebuilt the carbs for my 78 308, and they came back gorgeous. They are known as THE Weber shop in the US. Chat with them and see what they think it will take.

 

Why carbs?

Go for something like this - individual throttle bodies:

https://rennsportfactory.co.uk/product/308-itb-46mm

You get all the aural pleasure of carbs and none of the downsides.

 

You are in California. Step away from he crack pipe...

 

I'd say that's good advice, event if you weren't in California!

 

I see that Modena Eng. in Austarlia had a custom cast weber type manifold, that it just what I was looking for, if they still sell them !
thanks

Andrwe

 

I think that the answer is very much in the question. Asking for an inexpensive way to decimate the value of your car means you should either live with what you have or sell your car and buy one with carbs. Changing to carbs will be an expensive and time consuming process whose net effect will be lowering the value of your car significantly. I can't image a scenario where it would not be cheaper to just change cars. Add the fact that the car is in California and you will be making the car illegal for registration in your state.

 

Maybe the FI just works too well and Andy just prefers the routine tinkering that goes with carbs! You know the old saying, "If everything went smoothly, life would be boring!

But I do agree that selling the current car/buying one with carbs would be a lot easier!

 

And probably not a S***-Load,

But a FK-TON, CHEAPER.

 

some numbers to comtemplate:
the stock GTSi throttle body is one port, 2.613 inches in diameter, ie. 5.36 square inches of intake area
4 ea 2 bbl weber carbs = 8 x 40mm = 15.57 square inches of intake area
short of a blower, 4 carbs is the quickest way to get much more air into the engine.

 

"short of a blower, 4 carbs is the quickest way to get much more air into the engine."

Well... if an engine needs 500 CFM to make max HP, having 1000 CFM available won't produce any more. A naturally aspirated engine 'pulls' what it needs - no more. Of course, if it needs 500 and you restrict it to 400, power will drop. So the question is simply, does the throttle body provide all the air the engine can use? If it does, adding more CFM capability won't do anything.

I'm not saying that the carbs will or won't produce more power. They might; they might not. I assume that there were other engine changes made when Ferrari abandoned carbs. So to get any added power from carbs, you would have to ensure that cams/cam timing, ignition timing, compression, etc also duplicated the OEM carb cars. IOW, modify your engine so it is essentially a copy of the carbed 3x8.

Also, keep in mind that the two devices you are measuring are quite different. A throttle body opening is almost unobstructed; a carburetor typically has a double or triple venturi that obstructs a good deal of that 40mm diameter. You would have to do some fairly exact measurements of the area occupied by the venturi in the carbs but I suspect that the actual "flow" available to the engine with those 4 Webers is in the same range as the throttle body.

 

Oh I/We HEAR YOU .... in the sense that the "RUSH" of Carbs DOES THINGS to certain parts of the human 'anatomy.' Guys ... and Gals too.

Even FI WITH a Blower can't duplicate THAT.


BUT to GET what you are AFTER, the days of doing it on a beer budget wallet are over. LONG OVER.

NOW, IF your wallet can afford Champagne, GO FOR IT, MOST Certainly.


Just understand, it is much Cheaper in the long run, not to mention EASIER, and MUCH LESS Time Consuming with by far FEWER Headaches, to just BUY WHAT YOU WANT, a CARBBED Car.

And absolutely NO ONE Here will 'Fault You' for That.

 

Philosophical point noted, but let us not forget that the OEM throttle body can be easily enlarged, resulting in a notable improvement in the 'seat of the pants' throttle responsiveness.

As I showed and discussed here:

Enlarged Throttle Body – A DIY Product Review | FerrariChat

 

Did you perform a dyno or track test (lap time or 1/4 mile trap speed) to verify that the enlarged throttle body actually improved performance?

The thing that has to be taken into account is that a production engine is designed for street use. In the days BEFORE computer controlled engines with variable cam timing, variable ignition timing, variable exhaust and intake tracts, etc, it meant that an engine pretty much COULDN'T be set up for maximum power because that sacrificed too much performance where you really need it - in the midrange. The reality is that except in very rare circumstances - maybe the Autobahn at 2AM - you can't drive on the road at WOT for more than a minute, if that.

Comparing a modern engine with a 3x8 engine is not reasonable. Modern performance street car engines can run circles around the pre-computer performance cars simply because a modern car can optimize all the parameters for whatever the car is doing. If that's idling along though the neighborhood or in bumper to bumper traffic in downtown NYC on a 100F+ day, fine, it can do that comfortably. If it's blasting down that autobahn at 170+ MPH, it can do that too - equally comfortably. If you want to take your 1965 Dodge Coronet street Hemi and modify it to match a current stock Dodge Challenger Hellcat on the drag strip you can certainly make that happen. BUT the Hellcat is perfectly comfortable to drive to the grocery store; the only place you could stand to drive that Coronet is at the drag strip.

If you want more power out of a 3x8 engine, it's going to take a lot more than sticking some Webers (or whatever) on it. Frankly, IMO, the best option is supercharging. It's pretty much the only thing that will add a serious amount of power at a reasonable price and also have virtually no adverse affect on drivability. Significantly increasing displacement can also provide a useful power increase without affecting drivability but modifying the stock engine to increase displacement will cost several times the price of forced induction.

 

If you are going to supercharge the engine - you better tear it all the way down and rebuild it to ensure it can handle the pressure. It makes no sense to me to do this to a bottom end that is from the late 70's, early 80's. You will fail something.

It's a siren's song to get "more power". Very few of us drive to the limits of the car anyway. Just enjoy your old car, and if you want a go-fast car, go buy an MX-5 or an M2 or something like that.

 

All true but no reason he needs to use Ferrari application carbs.

 

Very flawed theory. The carbs will only give you the ability to make modifications that will lead to more power, they will not give you more power.

The car has low compression, a smog tuned non adjustable ignition system and cams that are low performance by the standards of a big RV.

The carbs would be a small part of a big expensive modification process. There are a few people here who have undertaken that, me included and if you can do the work yourself it will probably cost what the car is worth now. If you have to pay someone it will be real expensive.

 

True. I'm assuming you are referring to throttle bodies as I have not heard of anything else being substituted and used.

Or am I mistaken?

 

You were talking about the availability and expense of 2 sets of DCNF carbs for a Ferrari. Why use those on a custom engine?

 

I was under the (mistaken?) impression he was just gunna swap induction systems, Carbs for FI (and probably cams) and not much else.

I admit I know next to nothing about custom engine builds.

I'd want to use webbers at least at first blush, as they were OEM.

 

THAT was the guy I was referring to.

Sorry I got the car wrong, it was NOT a Mondi 8.

Apologies.




Neat story on how I was 'Introduced' to him and then MET him face-2-face years later.

 

There was no mention made of cams in the OP - just swapping the FI for carbs. But as Rifle D said, there is a lot more to be done to gain any power.

Re forced induction (super/turbocharging) - pretty much any production 'performance' engine/drivetrain can accept a 1/3 increase in power with no issues at all. Basically, that means limiting the boost to around 5 PSI. Some engines can handle a lot more without issues but 5 PSI is generally safe with nothing required except installing the 'charger. Obviously a supercharger is an easier aftermarket install than a turbo since no mods are required to the exhaust system.

I wouldn't hesitate to install a SC on my 328 and had budgeted money on two occasions in the past to purchase one - around 7k USD at the time. In both cases, in those years the IRS decided they needed my supercharger money. TBH, I've since lost interest in it and worry more about good air conditioning!