Side draft carbs on my modded EFI intake???

[Anonymous]

I am having a 1.5-2 inch hood clearance issue on my F100 with the modded EFI intake.

I am wanting to explore everything from adding scoop, to lowering the engine a little, to seeing about side draft carbs...

Here is the picture of what I have so far....

I am thinkging of mounting two of them to the side where the throttle body used to be, it is now a flat plate of aluminum...

What sidedrafts would work for this?? Possibly sometihng from a motorcycle??

IS this a feasable idea, or woudl it be too much of a pain to tune??

Thanks guys!

 

[Anonymous]

Sorry, sizemoremk, but that plenum will kill the carbs. Much of the fuel will fall out of suspension into the bottom of the box, and the engine will run like crap, if at all. Sidedrafts need a continuous high-velocity air path from the carb to the intake valve in order to funtion properly.

 

[xctasy]

I'm with Fordman75. But the option I favor is making your own intake manifold, and use the cheaper side drafts. Down drafts are simply the ultimate in perforamnce. $ FOR $, a set of three DCOE's produce similar power to IDA's or IDF's. The DCOE's are 40% cheaper, and yield maybee 20% less power if the intake manifolds are state of the art. IDA's/IDF's are right up there with a Hilborn or Haltch/Motec EFI system. Good company to be in!

Short turn radius bends cause the fuel to drop out of suspension. Like a tunnel ram, sometimes it will work well, but most of the time fuel will fail to atomise into vapour, and cost you drivability and fuel consumption. A stock EFI has a BSFC of around 0.50 pints per hp per hour at its 121 hp level. Shove some DCOE's on that manifold, and you may gain 50 hp with the right cam, but unless its at wide open throttle, its BSFC will rise to 0.65 or worse. That could be a 30% drop in mpg. Pretty shocking if you only doing 16 mpg at the moment.

If you want to use DCOE 45's, then make you own intake manifold, try an run the intake tracts straight in, and ensue that the total voume of all six branches is no more than 3 liters.

The rules are:-

*if there are bends, fuel drop out happens

*if total intake volume is more than 60% of engine's capacity (4.9 liters) then response will be hampered.

*Any thing bigger than 45 DHLA or DCOE DellOrto's or Webers have no cold start chokes. Same with IDA's and IDF's.So if you like you engine to work from cold, you'll have to use a 45mm side -draft carb.

Personally, I'd use side drafts. They are cheaper, and on bench mark engines, like Aussie 265 Chrysler straight sixes, they pulse tune as well as a good EFI system. There is 255 hp net at 5400 rpm in a mildly worked 4.3 liter engine with these DCOE 45 carbs and 40 mm chokes.
This example 4.3 liter engine uses a wild 302 degree cam, yet still has 300 lb-ft at 3000 rpm.


On a 4.9, it'd be a H-U-G-E wake-up call!

 

[Anonymous]

thanks guys, just thught I'd ask...

I may have to abondon the EFI intake idea, as I don't think I want to get into putting a hood scoop on and such....

I feel like an inch and a half would get me where I need to be, but I don't think I can rop the engine and tranny that far...

Might be needed to go ahead and just use the offy or cliffor intake....

Thanks again!

 

[twentyover]

Or you can try the cheap seats like some of us.

While its true a Weber DCOE is a more sophisticated carb (well, at lease more complex) and mokes more horseower than the old standby SU's, you may want to look at SU's as an alternative.

A pair of HD8's (2") off a 4.2 Jaguar, or even a trio of HS6's (1.75") from a Trimph (or the Hitatchi licensed copies off a Nissan 240Z) maight look good. Since they are constand depression carbs, you link the throttle shafts, and there is a pile of tuning information available.

Contact Z Therapy or Joe Curato if you want detail information. They should be able to get you started based on engine size and # and size of carbs.

All this stuff is still being made new by Burlen in the UK.