460 Ford Forum banner

1 - 17 of 17 Posts

·
Registered
Joined
·
18 Posts
Discussion Starter #1
I have seen them on a few trucks and multi engine tractors, looking for feed back with those that have personal experience with them and their application of useage. Predator carbs that is.

Thanks
Dave
 

·
Registered
Joined
·
18 Posts
Discussion Starter #3
moparman said:
made good power, hard to tune, part throttle and idle tuning is almost nonexistant, at least on the one I worked with.
Was this a new carb? Idle at this time is not a prerequisite, flatout and finding weak links is the goal.

Thanks,
Dave
 

·
Registered
Joined
·
1,232 Posts
no, it was used. Rebuilt several times to work out the kinks. One foot on the gas and one on the brakes to make it around turns without stalling, but wot was fine. Still though, I'd use a holley.
 

·
Registered
Joined
·
860 Posts
hard to tune,
You must have been messing with the race version which has only a rudimentary idle circuit. The street version is a breeze to tune - once you get the right metering cam on it the tuning is a single screw.

Brad
 

·
Registered
Joined
·
66 Posts
I used to run them on my pulling tractor. We basically have 2 positions idle and wot. They worked great on racing gas for that. However, I had them converted to alcohol and they didn't work near as well. The engine was 479 ci 15.5:1 comp. with a .723" lift cam (in and ex), dur @ .050 268(in) ,280(ex) (going from memory from 8-9 yrs ago). 3.85 stroke, 4.450 bore; 745 hp at 6800 and 620lb-ft at 5200(once again from memory) had C8 heads max port and polish.
What I experienced was on the big end the engine would "cough" and die almost like you turned the switch off. I fought this all season long talked to predator they told me do this do that etc. Nothing worked same results. The only thing I could figure was when the rpm would pull down a little, the doors would flap shut and kill the engine. I switched to Holley Dominators and the problem was solved.

Mike
 

·
Registered
Joined
·
5,316 Posts
My experiences with the Predator carburetors have been very positive and I really think that only a very good Holley would out run one in most applications where they are suitable. Two of them on a tunnel ram or blower will run spectacular at all throttle positions especially on a large engine.

I've never used the ones with the idle circuit, I don't think it's necessary on the Predator.

Tuning them is very simple but the real trick is that often you'll find a little is a lot. Adjusting the idle mixture and speed takes some getting used to but they will run great with little to no tuning.
 

·
Registered
Joined
·
360 Posts
I agree with Dave, they do work great. I never ran one on a n/a engine but they're awesome with a blower, at one point I ran 3 of them before I switched to Enderle injection.
 

·
Registered
Joined
·
3,195 Posts
I agree with Dave as well. I ran one on my 289 years ago and what a difference. You can't over carburate any engine with the Predator as they only flow as much air as your engine requires, up to 930 cfm. They're very easy to tune and very maintenance free once it is tuned. And the throttle response will scare you.


Doug... 8)
 

·
Registered
Joined
·
1,102 Posts
is 930 cfm the biggest they make?
compared to a dom 1050 is it night and day or?
i have ofteon thought about one but ya dont see many anymore why is that?
 

·
Registered
Joined
·
2,426 Posts
I ran Predators for years...great carb!! But its basicly a "race only" carb.
They dont work all that well at part throttle/cruising and idle.
They are really meant for WOT operation.
They are easy to tune, but they are very sensitive to small changes.
Some of the traits I have found in them are that 1) they work best on single plane intakes, 2)they work even better when they have a 2" inch spacer under them, 3) they dont like dual plane intakes, but if you use them on a DP intake, you can make it work better with the aformentioned 2" inch spacer. 4) even the so-called "street" carbs dont work any better than the non-street carb....their intermediate idle circuit is only marginally fuctional, 5) they love tunnel rams and roots type blowers!!

They are very simple compared to a Holley....they dont have nearly as many passeges as Holley's do.
People dont use them because of hood clearence issues....but more importantly, they dont use them because of intimidation...the fear of the unknown....its not a Holley, so they dont bother to mess with them.
But the design has been around for decades....dating back to the old "Kendig" style carbs.

I used to have a Predator carb that I tricked out...made a couple of custom fuel curve cams that were "in between" the ones offered by Predator, plus, it had room for me to hide a nitrous injector *inside* the carb itself!!
Oh yeah, I won some money with that carb on the streets!! I had a totally hidden NOS system on the car that NOBODY ever was able to find.
They'd all shine their flashlights around the intake and carb, looking for the plate or something, but little did they know, the NOS was plumbed straight into the venturi of the carb itself!!
I should have kept that one...it worked real good. :wink:
 

·
Registered
Joined
·
266 Posts
I also agree with Dave M and the rest in the affirmative. they are great carbs.
BUT they don't tune like a conventional venturi unit.
1. the mixture screw on top is quite sensitive., you will find your self adjusting by 1/16th of a turn or less over a couple of days of tune/drive/tune/drive
2. I have the street idle circuit carb but I don't use it. I have it fully seated in and shut off. My 67 gal has a 429 merc motor and a toploader. so idle speed isn't a big deal. my engine seems to like idling at about 900 rpm.
3. also correct on mounting on dual plane manifolds. use a 1 or better 2 inch spacer. I also knife edge ground the divider on my ebrk perf to help flow.
4. have a few spare rubber flappers to replace curled ones. they are very important to the operation of the carb. I have been told that leather of a certain thickness will work as well. but I haven't tried it.
4.a. the accel pump on the side is your main source of leaks make sure the plate and base are true flat. I use Indian head gasket shellac very carefully to seal it.
5. mount the carb with the throttle in the back for drag racing .
6. air vector direction is also important to the inlet on top. the carb doesn't like turbulent air. I have a homemade scoop with an air foil installed to direct air straight down in a laminar flow into the carb.

As a side note, I met old man Kendig some 10+ years in Fesno. He is quite a guy. self taught engineer type, and he has spent way way to many hours alone in the shop, with too many hydrocarbons floating around. Be he was very smart. showed me a original Kendig he hand made.
Told me all about the differences between it and the predator.
Also I got from him some original engineering prints and flow data info.
I've held on to them for all this time. He also gave me something very interesting.... a prototype idle circuit fuel metering device that was in car tunable. It was meant to work with the screw on top of the carb, to provide further precision to the mixture ratio. It used a small needle and seat solenoid off a GM rochester feedback carb of the 80's to control fuel flow.
I may pull it out of the safe and see if I can make it work one of these days..


Dane V
www.fordautowrecking.com
 

·
Registered
Joined
·
18 Posts
Discussion Starter #14
Thanks all for your replies, I appreciate the time that it takes for everyone to give me their imput on my question.

Dave
 

·
Registered
Joined
·
5,316 Posts
It's a good point to mention that the Predators do like running on a 2 inch spacer and I think it's mostly due to the fact that intake manifolds are generally designed with the discharge pattern of a Holley or Carter AFB in mind instead of the one produced by the spray bar in a Predator. The spacer helps to reduce the incompatibility shown by some intakes.

I've really never experienced any trouble running at any throttle position with a Predator. One thing to remember is that the position of the cam and idle screw is VERY critical if the carb seems just a touch rich or lean off idle at part throttle try adjusting the idle mixture richer or leaner a VERY small amount and try it again, I think you'll find that it will run great at all throttle positions.

Also if you're new to the Predator I would recommend installing the carburetor on some mild old engine, starting it up and then experimenting with getting it to idle as good as possible. Take your time, make small changes till you get it running good. Then put it on your other engine that maybe has more cam etc. It will be very close and only take a minute or so to get just right.



Having no power valve the carburetor will not give exceptional economy when street driving but I think they can run with the best especially on a blower or tunnel ram.

The accelerator pump diaphram is about the only real weak link in the carburetor sometimes those can be leaky.
 

·
Registered
Joined
·
1,232 Posts
Brad Johnson said:
hard to tune,
You must have been messing with the race version which has only a rudimentary idle circuit. The street version is a breeze to tune - once you get the right metering cam on it the tuning is a single screw.

Brad
I think it was converted to street version. From seeing other's posts on here, I think most of the problem was the motor itself. It was a 440 ci lucky to be 8:1 compression, stock valve, ported smog heads with a [email protected] .470" lift and 108 LS. Dual plane action plus manifold. Like previously mentioned, the throttle response was great. I'd be interested to see what the carb would do on a larger motor with compression and good heads.

Has anyone tried one of these with a blow thru setup? I'm extremely curious to know how it worked out if you have.
 

·
Registered
Joined
·
2,426 Posts
I never heard of anyone trying to use them as a blow thru type. Not sure how well it would work, since they have the air flaps on top and they are linked with the fuel metering system. Maybe it would work, never tried.

As was stated, their mixture discharge out of the main body is different from that of a Holley,, Carter, or any other "normal" type of carb.
They tend to direct the exiting mixture into the center of a manifold instead of at the outer corners like the other carbs.
Because of this, the mixture needs more "space" or plenum area to straighten out and make a turn into the ports....thats why a 2" inch spacer works awesome under these things.
 
1 - 17 of 17 Posts
Top