Any carb tuning 'gurus' here?

**CaptCrunch** · 08-09-2003, 10:40 AM

Well while it is real hard to figure out what is up with the carb from what you have listed (need more specfics of how it idles... does it seem lean rich, what jets you running? What accelerator pump and shooter? Have you doubt check the other essentials like timing? blah blah blah)

I also will go to say that that anything with the name proform on it is junk. All that company does is buy the cheapest and often crap parts made overseas and put their name on it.

I have a number of carbs around... 600 quadraget, 800 quadrajet, 650 DP, 750 vac secondary... You could either borrow one to try and see if it solves your problem or may sell depending on a price. Most of them are pretty fresh.

**KrisR** · 08-09-2003, 12:23 PM

I am very tempted to just order a new one and be done with it. I'm also interested in one of yours to try/buy if you have one that's close to what you think I need.

On my car, what carb would you recommend? (i.e. Holley or Edelbrock, 650 or 700, vac sec or DP). On a street/strip car, will I always have driveability issues with a double-pumper? Do they make much more power than a properly set up vac-secondary one? I'd love to get this car running as optimally as possible. Would the carb I order come with a decent setup, or will I have to adjust everything right away?

Sorry for the amount of questions, I'm just curious about this stuff now.

Thanks again,
Kris

**CaptCrunch** · 08-09-2003, 11:06 PM

No problem on the questions.. ask away.

Let's see... well first off I have run double pumpers for years and have never had issues, but they generally need some modifications to be a fairly decent street carb. I like a 650 DP because I like to build up high winding small blocks that get a fair share of street miles. The 650 DP can handle the fuel needs of almost all but the nastiest small blocks and still have great low end throttle response and driviability of a smaller carb. If you don't have a built lower end, plan to rev past 6 grand, and/or will only see hard race like use once in a blue moon... then save your money and just get a single. I'm guessing from your combo listed and your heads that you really don't need the DP. The DP's are jetted quite a bit richer, have larger idle feed passage which makes for a richer idle (to help support those nasty idling cams). One trick I use is to drill out the idle air bleed passages very slightly. This effectively leans the idle out a bit. I also do a lot of tweaking with the main jets to allow me better driviability.

On vac vs mech secondaries... well basically mechanical let you precisely control when they open, where as with a vac secondary the secondaries are actually opened by venturi vacuum ( air being pulled through your primaries). The big down side here is if you over carb you secondaries my never open fully so it is crucial you don't over carb with vac secondaries. The real atvantage of a vac secondaries is that the primaries open more gradually then mechanicals which not only makes for better milage and street manners, but also will cause less wheel spin then a mechanical.

To be 100% truthful... if you aren't concerned with and extra 5 hp or want the easiest carb to tune, just pick up an Edelbrock (aka Carter AFB). They are so easy to tune... anyone can do it. They are also very easy to rebiuld... heck can do it pretty much with the carb still on the intake. Alot of guys diss the Edelbrocks saying they cost power. Well a badly tuned holley will cost you more power. On a nasty race setup it will cost you some power, but nothing real noticible on a street engine. If you keep wih a Holley I would take some time to purchase and read good book on Holleys. It will teach you a lot and guide you through the essentials.

**KrisR** · 08-10-2003, 10:07 AM

Thanks for all the advise -

I'm 99% ready to order an Edelbrock. I've had others tell me they have run those and liked them too. I just need to know what size to get (they only sell 600s and 750s)...

Engine is an '88 roller-cam block with .030-over Wiseco flat-tops (est. 9.3:1 c.r.), balanced bottom end, with the above-mentioned cam and heads. Eventually I'll probably get a good set of heads (Trick Flow probably), so I don't want the carb to be the limiting factor.

Which carb would you get?

Kris

**CaptCrunch** · 08-10-2003, 05:21 PM

Well just looked up the specs on that bumpstick and she is a stout liittle cam for a 302. What gear your running and how do you plan to use the car? If you want the power up high and are willing to lose the benifits of a 600 go for the 750. You can always modify it a bit. If I rememebr right the biggest difference in those two carbs is the main jet size. A 750 will run much richer. I'm not super knowledgable on the edlebrocks but I know that I would rather under carb a street car then over carb it. I also know a number of my ford friends have run built 302's on edlebrock 600's right out of the box. So the 600 would be my choice for the street car/occasional strip car.

**KrisR** · 08-10-2003, 07:34 PM

I currently have 3.73s. I think the T-5 my car has is out of a T-Bird Turbo, which has shorter transmission ratios, so it feels like 4.10s might with a Mustang-geared T-5.

The car will be a weekend play car, and a quarter-mile car once a month or so. Driveability isn't the main concern, but I'd like a reliable (if rough) idle and decent around-town manners.

Kris

**DNeinstadt** · 08-11-2003, 07:34 AM

Dave borrowed my 750 Edlebrock for a week or so and supposedly it ran great. Just FYI Kris.

Dan

**KrisR** · 08-11-2003, 02:06 PM

Thanks Dan!

That's one of the ones I'm looking at. I'm looking into it furthur.

Kris

**CaptCrunch** · 08-11-2003, 09:43 PM

There ya go.. I personally would probably use a 600 on it except if it was a straight out race application.

**Dave** · 08-15-2003, 07:15 PM

Hey Kris,

Yeah I borrowed Dan's carb a little while back and it ran WAY better-it was rich, but definitely ran better.

**KrisR** · 08-15-2003, 08:45 PM

Originally posted by Dave
it was rich, but definitely ran better.

I agree with this!

It is pig-rich right now, but runs decent. I'm sure it'll work great with different jetting/springs/etc. Unfortunately Checkers has to order the parts, so it won't be until next week before I can install them.

I feel sorry for anyone who has to follow my car....

It stinks!

**Ford Fan** · 08-16-2003, 02:30 AM

Not to disagree that your car is running rich but mine stunk really bad. I thought for sure it was rich. I took it to the dyno and it was 15.1:1 air fuel, extrememly lean. I asked Brian about it (Hi-tech motorsport) and he said pretty much any car without cats. is going to smell rich. Just an FYI, Nick

**winker** · 08-16-2003, 05:50 PM

Originally posted by CaptCrunch
...If you keep wih a Holley I would take some time to purchase and read good book on Holleys. It will teach you a lot and guide you through the essentials.

The best line of advice anybody could ever give re: Holley Carbs. It's almost an art rather than a science.

**CaptCrunch** · 08-16-2003, 08:44 PM

Originally posted by KrisR
I agree with this!

It is pig-rich right now, but runs decent. I'm sure it'll work great with different jetting/springs/etc. Unfortunately Checkers has to order the parts, so it won't be until next week before I can install them.

I feel sorry for anyone who has to follow my car.... It stinks!

Yeah your car stinks Kris LOL! I'm pretty sure that was you I passed on 35E south Friday afternnon going home from the internship. I just kinda gave you a nod as ya looked over... I'm ashamed to be seen covered in sweat and dirt... none the less in my beater Talon turbo rice machine

Looking nice man! I really dig those 4 eyed models lately! I really couldn't smell much, but I was amazed how quiet it was... talk about sleeper.

Any carb tuning 'gurus' here?

Any carb tuning 'gurus' here?

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