Converting from EFI to Carb on my '94 Cobra - Need Intake and Carb suggestions ASAP!

[69mach03]

Converting from EFI to Carb on my '94 Cobra - Need Intake and Carb suggestions ASAP!


I've spent weeks trying to get the car running right. It won't idle down past 1400 RPM without going into a radical lope, i.e. searching / hunting, until it stalls. I've got a TwEECer and Zeitronix wideband on the car. Been on and off the phone with my tuner. Made a thousand adjustments to the tune, ISC screw on the T/B, adjusted the TP, messed with the IAC, etc. Lost ground on the TP, ran an auxilary ground wire to the firewall. O2 sensors are losing voltage. Don't know if its an electrical problem, PCM, IAC, MAF... Drag racing season is HERE and I'm tired of working on the car. (100% burnt out) /End Rant


OKAY. I'm ordering a carb setup THIS EVENING. I need your suggestions!


Stock shortblock with AFR 165 heads (went from 64cc stock GT40 heads to these, which are 58cc -- may have moved the compression ratio from 9.0:1 to about 10.0:1)

Anderson Ford Motorsport (AFM) N-41 Cam (2600-6200 RPM powerband)
Crane Lifters, Crane 1.6RR

Performance Automatic C-4, Approx. 3000-3200 Stall Converter

This car is used for DRAG RACING PURPOSES ONLY.



Intake Manifolds

Edelbrock Torker II, EDL-5021, 2500-6500 RPM, Single Plane
Edelbrock Performer RPM, EDL-7121, 1500-6500 RPM, Dual Plane
Edelbrock Performance RPM Air-Gap, EDL-7521, 1500-6500 RPM, Dual Plane


Carbs

Holley 4777S - 650cfm, Manual Choke, Mechanical Secondary / Double Pumper
Demon 1282010 - 650cfm, Manual Choke, Mechanical Secondary / Double Pumper
Proform 67199 - 650cfm, No Choke, Mechanical Secondary / Double Pumper



I need some real advice TODAY. Ordering in the next few HOURS. Thanks, fellas.

 

[Toasty]

Converting from EFI to Carb on my '94 Cobra - Need Intake and Carb suggestions ASAP!


I've spent weeks trying to get the car running right. It won't idle down past 1400 RPM without going into a radical lope, i.e. searching / hunting, until it stalls. I've got a TwEECer and Zeitronix wideband on the car. Been on and off the phone with my tuner. Made a thousand adjustments to the tune, ISC screw on the T/B, adjusted the TP, messed with the IAC, etc. Lost ground on the TP, ran an auxilary ground wire to the firewall. O2 sensors are losing voltage. Don't know if its an electrical problem, PCM, IAC, MAF... Drag racing season is HERE and I'm tired of working on the car. (100% burnt out) /End Rant


OKAY. I'm ordering a carb setup THIS EVENING. I need your suggestions!


Stock shortblock with AFR 165 heads (went from 64cc stock GT40 heads to these, which are 58cc -- may have moved the compression ratio from 9.0:1 to about 10.0:1)

Anderson Ford Motorsport (AFM) N-41 Cam (2600-6200 RPM powerband)
Crane Lifters, Crane 1.6RR

Performance Automatic C-4, Approx. 3000-3200 Stall Converter

This car is used for DRAG RACING PURPOSES ONLY.



Intake Manifolds

Edelbrock Torker II, EDL-5021, 2500-6500 RPM, Single Plane
Edelbrock Performer RPM, EDL-7121, 1500-6500 RPM, Dual Plane
Edelbrock Performance RPM Air-Gap, EDL-7521, 1500-6500 RPM, Dual Plane


Carbs

Holley 4777S - 650cfm, Manual Choke, Mechanical Secondary / Double Pumper
Demon 1282010 - 650cfm, Manual Choke, Mechanical Secondary / Double Pumper
Proform 67199 - 650cfm, No Choke, Mechanical Secondary / Double Pumper



I need some real advice TODAY. Ordering in the next few HOURS. Thanks, fellas.

Its been a long time since I did any carbed engine work, but I always used to put single plane intakes in my manual trans 5.0's (wayy back 'in the day'). The single plane seems like a good choice based on my admittedly dated information.

I've used the Torker II intake a few times in the past with good success before there wasnt an air gap choice available from anyone.

Since its a drag car, I'd go single plane, and the torker seems like the best bet based on my old knowledge. I'm not sure about the air gap intake.

I'd double check what ur buying too. From Edelbrock's website;

PERFORMER RPM™ MANIFOLDS (1500 to 6500 rpm)
Performer RPMs are dual-plane, high-rise intakes with 180° firing order to produce incredible top-end horsepower while retaining good throttle response. Their larger plenums and runners match the free-flowing exhaust, high-lift cams and other modifications of a high output engine. They are intended for high-performance street or competition engines that run up to 6500 rpm. They are not for emissions equipped engines. Edelbrock's Performer RPM gives you the ultimate in street high-performance.

PERFORMER AIR-GAP® & RPM AIR-GAP® MANIFOLDS
This award-winning design incorporates the same race-winning technology that's been used on our Victor Series competition intakes for years. The air-gap design features an open air space that separates the runners from the hot engine oil resulting in a cooler, denser charge for more power. RPM Air-Gap manifolds are modeled after Performer RPM intakes for high performance street power from 1500-to-6500 rpm, and the new Performer Air-Gap manifolds are ideal for street performance from idle-to-5500 rpm.

TORKER II® MANIFOLDS (2500 to 6500 rpm)
These single-plane, low-rise intakes work well for high-rpm, high-performance street applications. Ideal for applications where hood clearance is limited, they produce gains in top-end horsepower with adequate throttle response. Not intended for mileage or emissions applications, they are only for high-performance vehicles.


So the Performer Air-Gap is only good for idle-5500. The RPM Air Gap is good for 1500-6500.

Why not call Edelbrock and see what they suggest.

</ramble>

 

[SVTCobra306]

Air Gap FTW...

With your setup I would go with an Air Gap and either a Holley HP 650 carb or a Quick Fuel 650 mechanical secondary. Call and talk to QFT, very knowledgeable folks there, you won't be disappointed!! The ProForm is OK but for a little more money you can do better. Demon hasn't impressed me lately.

For the intake, do some searching around on the 'net. Usually it is used to baseline against the big intakes (victor, parker, etc) but it usually actually beats them to 6000, sometimes even 6500... Unless you are going north of that and never below 4000 you will come out better with the air gap.

Don't forget you have to change your fuel system. You might get away with one of the conversion regulators for a while, but what you need is a lot of fuel volume at low PSI (7-8ish). Something like a holley black and an 8an feed will get you a long way...


Honestly it sounds like a nice fat wire (12 gua. minimum) from the engine mount bolt on the block side to the frame would probably cure your woes.. I fought this late last year and was pulling my teeth out too. I didn't have a racing season looming, but I was losing time working on my race car and was getting frustrated. I was convinced that the ground on the timing cover was adequate. I upgraded it to 10 guage and the condition improved temporarily then returned. Mine was a tad different, mine would idle but with a miss, was OK part throttle but shit itself when you loaded the car. I put in new O2 sensors, replaced the TFI module to no avail. In the end all it took was replacing the burnt ground wire from the motor mount bolt to the front stub rail. I put one on each side to make me feel better the wire was free after all..

 

[69mach03]

Air Gap FTW...

With your setup I would go with an Air Gap and either a Holley HP 650 carb or a Quick Fuel 650 mechanical secondary. Call and talk to QFT, very knowledgeable folks there, you won't be disappointed!! The ProForm is OK but for a little more money you can do better. Demon hasn't impressed me lately.


Honestly it sounds like a nice fat wire (12 gua. minimum) from the engine mount bolt on the block side to the frame would probably cure your woes.. I fought this late last year and was pulling my teeth out too. I didn't have a racing season looming, but I was losing time working on my race car and was getting frustrated. I was convinced that the ground on the timing cover was adequate. I upgraded it to 10 guage and the condition improved temporarily then returned. Mine was a tad different, mine would idle but with a miss, was OK part throttle but shit itself when you loaded the car. I put in new O2 sensors, replaced the TFI module to no avail. In the end all it took was replacing the burnt ground wire from the motor mount bolt to the front stub rail. I put one on each side to make me feel better the wire was free after all..

I'm leaning towards putting an RPM Air-Gap on it after all. But I may give Edelbrock a call directly before the day is over (thanks Toasty).

As for the grounds, I've added a passenger side ground strap to the frame and a 12 gauge wire from the passenger cylinder head to the firewall. Still can't figure these electronics out and I'm tired of troubleshooting the issues. The car won't idle worth a damn and I've been hard on the trans just trying to get it moved around the shop. :bored:

 

[STAMPEDE3]

RPM air gap. 1500-6500

And either the Holley or the Demon.
I normally go Holley but I know a lot of guys switching to the Demons with good luck.

IMO they are about =

 

[My94GT]

stay FI take your car to a person and have it tuned right. im in the middle of having bugs worked out on my car and while i drove it in stop and go traffic for over an hour had no problems with it idle hunting. im personally just a fan of FI

other then that good luck with the carb hunt im sure there are alot of people with some good advice on it.