Mech injection V's carbs
Moderator: Team
Re: Mech injection V's carbs
Geoff2, as cool as the quad webers are, would you seriously consider drag racing with them?
Re: Mech injection V's carbs
The power comparo is WRT fuel delivery only.
An EFI with port injectors permits manifold shapes and volumes that are impossible to live with carbureted.
An EFI with port injectors permits manifold shapes and volumes that are impossible to live with carbureted.
Re: Mech injection V's carbs
Calypso,
I have had quad Webers on my 455 powered GTO, for about 11 years now. Street registered & street driven. [ I also ran them on a 440 Chrysler in the 1980s ]. I would certainly drag race it with no qualms....but for a couple of 'issues'. Even with a 3.08 axle it is uncontrollable in 1st gear. To get control...& the use of... 1st gear would require using slicks. Slicks, in turn, would require replacing the weak factory 10 bolt diff with something stronger. While I have made changes to the car [ Webers, for example ] most of it is remarkably stock & I want to keep it that way.
There are a couple of basic 'don't do' with Webers: don't run more than about 3 psi fuel pressure; fuel level is critical; throttle linkage is critical in having minimal play & all carbs returning to their idle stops. Once you keep these things in mind, they are a veeery easy carb to tune & do NOT require constant attention if the above is noted. Do these things & you will be rewarded with fuel injection like performance, good economy & an idle quality that would require 15-20* less duration if it had a 4 bbl.
I have had quad Webers on my 455 powered GTO, for about 11 years now. Street registered & street driven. [ I also ran them on a 440 Chrysler in the 1980s ]. I would certainly drag race it with no qualms....but for a couple of 'issues'. Even with a 3.08 axle it is uncontrollable in 1st gear. To get control...& the use of... 1st gear would require using slicks. Slicks, in turn, would require replacing the weak factory 10 bolt diff with something stronger. While I have made changes to the car [ Webers, for example ] most of it is remarkably stock & I want to keep it that way.
There are a couple of basic 'don't do' with Webers: don't run more than about 3 psi fuel pressure; fuel level is critical; throttle linkage is critical in having minimal play & all carbs returning to their idle stops. Once you keep these things in mind, they are a veeery easy carb to tune & do NOT require constant attention if the above is noted. Do these things & you will be rewarded with fuel injection like performance, good economy & an idle quality that would require 15-20* less duration if it had a 4 bbl.
Re: Mech injection V's carbs
More on Webers v 4bbl.
I dd a lot of work on a friend's Pontiac. Here are the specs: 463 CI Pontiac engine, ported alum heads [ with ports that are too BIG for the application ], 4000 lb without driver, 3.23 diff, T400 with 3200 stall c'ter, mild hyd roller cam, 236/230 @ 050 [ notice LESS exh duration ], 112 LSA. { This cam has 10* less exh duration than the factory RAIV cam, the largest cam used by Pontiac in a production engine, 231/240 @ 050, 113 LSA }.
The engine had these stock parts: RAIV intake manifold, RA exh manifolds [ no headers ], Chrysler 440 TQ carb, cold air induction. The driver had NO drag racing experience & the car was raced at Eastern Creek drag strip in NSW, Australia with street radial tyres. It ran 11.9 @ 113mph. There was no at-track fine tuning done, such as ign timing or the various adjustments that can be made to the secondaries on the TQ carb. With some tuning, & more driver practice, I'm sure another tenth or two improvement would have been possible. Sub 12 sec, not bad I think for exh manifolds, production carb, 3.23 axle & inexperienced driver...
When people looked at the 'funny' carb & asked, why don't you use a Holley, the owner's reply was 'I want to go faster'...
The TQ was swapped for a pair 44 Weber IDFs, bolted onto as very poorly made 4bbl adapter. Owner wanted to keep everything under the bonnet & the Webers are about 3/4" taller than a 4bbl. A cold air induction air box with filter was fabricated. 44s were chosen over 48s because this was predominantly a street car. On the dyno, it picked up 36 rwhp with just the change to the Webers. I cannot remember the times/mph it ran, but it WAS quicker than the 4bbl; 117 mph rings a bell, but not 100% sure. . If I was to do this again, I would use a cross ram adapter to use side draft Webers. For a Chev/Holden, these manifolds are available as a one piece, streamlined design; & 55 DCOE sidedraft carbs are still available.
I dd a lot of work on a friend's Pontiac. Here are the specs: 463 CI Pontiac engine, ported alum heads [ with ports that are too BIG for the application ], 4000 lb without driver, 3.23 diff, T400 with 3200 stall c'ter, mild hyd roller cam, 236/230 @ 050 [ notice LESS exh duration ], 112 LSA. { This cam has 10* less exh duration than the factory RAIV cam, the largest cam used by Pontiac in a production engine, 231/240 @ 050, 113 LSA }.
The engine had these stock parts: RAIV intake manifold, RA exh manifolds [ no headers ], Chrysler 440 TQ carb, cold air induction. The driver had NO drag racing experience & the car was raced at Eastern Creek drag strip in NSW, Australia with street radial tyres. It ran 11.9 @ 113mph. There was no at-track fine tuning done, such as ign timing or the various adjustments that can be made to the secondaries on the TQ carb. With some tuning, & more driver practice, I'm sure another tenth or two improvement would have been possible. Sub 12 sec, not bad I think for exh manifolds, production carb, 3.23 axle & inexperienced driver...
When people looked at the 'funny' carb & asked, why don't you use a Holley, the owner's reply was 'I want to go faster'...
The TQ was swapped for a pair 44 Weber IDFs, bolted onto as very poorly made 4bbl adapter. Owner wanted to keep everything under the bonnet & the Webers are about 3/4" taller than a 4bbl. A cold air induction air box with filter was fabricated. 44s were chosen over 48s because this was predominantly a street car. On the dyno, it picked up 36 rwhp with just the change to the Webers. I cannot remember the times/mph it ran, but it WAS quicker than the 4bbl; 117 mph rings a bell, but not 100% sure. . If I was to do this again, I would use a cross ram adapter to use side draft Webers. For a Chev/Holden, these manifolds are available as a one piece, streamlined design; & 55 DCOE sidedraft carbs are still available.