Time for a New Carb?

[Rickd]

Just have 200 miles on my Cobra over the weekend(car had 2000 miles prior over a 5 year period .. not driven much). 302 with around 300 HP, Holley 600 double pumper.Poor throttle response or control. Street use .. not on a track. I'll be in second or 3rd gear just staying with traffic .. and pressing on the pedal has no response .. press harder .. and VROOM .. it'll take off. The linkage appears to be fine and not binding. The carb might need a rebuild after 5 years of basically being in storage?

I've been reviewing prior threads on carbs and to the uninitiated (and someone who is NOT a mechanic) it seems like a Quick Fuel Tech carb would be a good thing for enjoying the cobra for the long term. I've got to take the car in to have some gaskets changed and It seemed like a good time to go for the carb 'upgrade' at the same time. Quick Fuel Tech with vacuum secondaries .. choke?? (Present Holley set-up has a manual choke). Seems like a lot of people start with a Holley and then move on to what appear to be more reliable and consistent performers (Quick Fuel, Demon).

Comment would be appreciated.

Thanks,
Rick

289 FIA, #9299, Viking Blue, 302 HO, T-5

[Brent]

Rick,
Stay away from the double pumpers if your looking for a "cruising" carb. A nice vac. secondary will work well. The Demon, Quick Fuel, Barry Grant, Holly H.P., etc. work very well and make a big difference on a hot motor. I do not think they will give you any seat of the pants horsepower gains on a 300 HP motor. They do meter fuel better and you may get smoother throttle transition with them and on the nicer carbs. the vac. secondary is easily adjusted with a thumb screw. The stock Holley vac. secondary can be a pain in the a$$.
On the flip side a rebuild kit is A LOT cheaper.

I have a Demon and I really like it. I know of three people running the Quick Fuel Tech. and they love them.

have fun!


Brent
427 SC Chassis #4279401
Candy Apple Red/White
402 FE/Toploader/3.54

[souzape]

Rick- it sounds like your problem might be the accelerator pump on the secondary side of the carb. Minor issue. We all tend to lavish a lot of attention ($) on these cars but from your description of driving requirements/habits the practical answer might be one of the little Edelbrock AFB knock-offs (probably around 650 cfm for your 302). The non- emission models work great right out of the box and tend to be very low maintenance based on my experience. You can spend a lot more for some of the exotic, high end carbs and at the limits you would likely get more performance and some serious bragging rights, but the performance boost would not be terribly noticable in even spiritied daily driving. That's one rational answer to your querie. If you decide to go that route (Edelbrock) you could take the money you would save and get a good dyno tune in the deal. Whatever you decide, don't be tempted to over carb your little Windsor....650 cfm is probably the max unless you've got lots of cam and headwork.

Good luck

Phil Souza

[gasman]

Rickd, You probably read my thread on switching to the Quick Fuel Technology carburetor. Let me give you an update before you make your decision. I bought my car used with 2000 or so miles on it last year. When the car was delivered, I noticed it was running excessively rich. I also noticed the oil consumption was excessive. I changed out the carburetor to the Quick Fuel Technology, which made the car run incredible, however, the oil consumption problem became worse. I pulled the motor out and took it to Bill Parham. Bill rebuilt the motor and started it on his run stand. I went to pick it up and he said “I will not warranty this motor with that carburetor on it, this is what destroyed your motor”. I explained why we had switched carburetors and he said, your old may have been rich but you run this carburetor on your car and you will be back in here in no time at all. Now to be fair to Quick Fuel Technology, the box had a warning label on it. The label read "For Circle Track Racing Only".

Steve Foushee
Unique #4279389

[will butterworth]

Rickd, running a 650 edelbrock on a 92 ho 302 with about 300 hp, perfect match, no trouble at all. Little 300 hp engine is pretty much family street stuff, will handle most all street stuff-esp. those fart tube cars the kids challenge you with now days, but do need to pick your fights.Thursday 2- cents worth, Will-alabama

[will butterworth]

Rickd--forgot , gets fair mileage too, 22 to 28 mpg, Will-alabama

[JeepSnake]

Rick,

Before you begin a carb swap, I'd advise going through what you have - and by "going through," I simply mean giving it a thorough cleaning, checking for correct OEM tolerances, etc. Not getting into fine tuning, changing jets, etc. As you indicate, you'll most likely find varnish and crud problems. If all else fails, I'll chime in for the Edelbrock Performer (i.e. old Carter AFB design).

If nothing else, start simply by running a couple of tanks of high-test through the car with SeaFoam fuel treatment added.

With the Weber on my old Jeep inline six, I ran into a problem which could affect any carb, particularly in cold weather. Drag Reducing Agent or Drag Reducing Additive (DRA). It's a "slickem" substance that lets the pipeline companies pump more product with less pump horsepower (up to 50%!). Normally, it won't cause problems, but it CAN clabber up in the fuel bowls - it will look like little globs of semi-transparent dielectric grease, or paraffin, and the stench is nauseating! I've had it happen in really cold weather with the Weber, giving exactly the symptoms you've described. A good add-to-the-tank cleaner clears it up.

Additionally, I have taken to running two fuel filters on our older carbureted vehcicles (CJ-5 and Chevelle) - one right off the tank to protect the pump, and one just ahead of the carb to double protect it. You'd be amazed at the crap you get even out of a brand new tank (e.g. bugs, spiders, varnish, grit, water, etc.)!

Hope this helps,
ZACH

Zach Butterworth
Apple Mt. Cobra Pit Crew
(Mom & Dad's 427)

[Brent]

Performance Carbs require set up and adjustment once on the motor. A carb builder can spec one close but it is really just an educated guess based on your motor combination. If you take a carb apart you will see that it has very few moving parts. Usually easy to diagnose and cheap to fix (one of the few things on a motor that is )-: )

Steve,
Bill has a great reputation and builds a quality power plant, however, in this case I think he seized an oppertunity to pass blame on the one piece of the motor that did not come from him. It may have needed a jet change, needle and seat lowered, idle mix screws adjusted, bad or wrong power valve...But I doubt it was junk and ruined your motor.



Brent
427 SC Chassis #4279401
Candy Apple Red/White
402 FE/Toploader/3.54

[TurnpikeBoy]

<img src=images/icon_speech_ok.gif border=0 width=17 height=15 alt=Insert Speech Icon: OK>, good timing on this.

IF you want to stay with the Holley-type carb, BUT want to switch it to something else like a Demon, get in touch with Don Gould at www.4secondsflat.com and he will make you whole.

What he cannot do for you in setting a carb up initially, he will walk you thru when it's on your car. Excellent, excellent carb guy - he's a rep for Demon and truly knows his sh!t, Demon or Holley or Carter or....and he will answer your questions with straight answers whether you ever bought anything from him or not.

This guy is FIRST CLASS.

Yeehah

[Brent]

<img src=images/icon_speech_yes.gif border=0 width=23 height=15 alt=Insert Speech Icon: Yes!>

I spoke to Don and bought my Mighty Demon from him. A1 guy and he really knows his $hit.



Brent
427 SC Chassis #4279401
Candy Apple Red/White
402 FE/Toploader/3.54

[Rickd]

Turnpike. With that "yeehaw" signature .. you sound like you might be into CAS. I've got a call into Don to talk about the Road Demon .. sounds like a good choice frp, what I've read, and I appreciate dealing with someone who "knows his $hit". Thanks all for the comments. Rick

289 FIA, #9299, Viking Blue, 302 HO, T-5

[TurnpikeBoy]

quote:Originally posted by Rickd

With that "yeehaw" signature .. you sound like you might be into CAS.


Tha may be about the only kind of shooting I haven't tried yet, Rick. Still stuck on trap and 200/300/600 yd. hi power; and since I'm innately shy to begin with ([:I]:D)I would have some issues with the dress code. Weather here in Pennsy is breaking and I'm really looking forward to getting back on the long ranges - just too damn cold in the winter anymore.

You are assured you will find Don Gould to be about the most consummate professional out there - I've worked with carbs since back in the 60's, set up many on drag racers (which is much simpler than road course cars)and thought I knew plenty....I'm here to tell you his knowledge is truly profound. He WILL save you money and make the car run right, without even breaking a sweat. Outstanding gentleman on top of it all.

Roger Payne

Yeehah

[Rickd]

Spoke with Don re Demon carbs. Certainly knows of what he speaks. He recommends that I go with a 575 Speed Demon set up for my little 300 HP 302, with mechanical secondaries. Also wants to recurve the distributor and says he can get that motor to run real nice on the street, with a good boost when I want it. Everyone has been recommending vacuum secondaries, and I kept suggesting them, but he said that mechanicals are the only way to go with the small motor.

289 FIA, #9299, Viking Blue, 302 HO, T-5

[TurnpikeBoy]

I have the alum. X-head 302 with a B-303 cam; Barry Grant Enterprises told me go wioth a 650 Speed Demon, mechanical secondaires at 1:1 ratio. OK, you guys are the pros, so I did. Mind you I thought that vacuum second's were the way to go also.

Boy, I am glad I did. And Don concurred with their recommendation.

When you jump the throttle the power output is RIGHT NOW - no waiting for the secondaires to open up and start making power. There are a couple big block Cobra owners we ride with that have been genuinely surprised at just how quick little motors can be.

Tuning wll not be a problem. And once all is right with the world, your grin will be a permanent fixture on your face when you squeeze that go pedal.

Yeehah