donyue

Hi Mike, well if you are going to purchase a new carb then I would recommend a Quick Fuel or Proform carb as I have read and been told by my engine builder that they are much better than the base Holley's. I'm not sure what the high end Holley's are like but I know they are a lot more money.

JMHO....

bondoboy

What it comes down to is, if you want a holley, put on a holley. If you have good luck with q jets, keep using them. I've had some q jets that worked fine and I kept using them. I've had others that didn't matter what you did to them, they just always had problems. I think sometimes worn shafts and warped carb bodies are the culprit. That being said, I prefer the holley, but everyone has their preference and their motor may run better with one carb instead of the other. Use what works for you. As far as the k&n goes, I've had a few and never felt any more power with one. It may show on a dyno, but I couldn't tell by feel. I understand the idea behind them, I just prefer the paper. Also, the purple looks funny when you want a vintage look. The main negative to the k&n is that a service takes so long. It takes so long to dry before you can re oil it. If you aren't in a hurry, it's no big deal. The main point is: use whatever makes you happy. Everything has good and bad points and everyone has their opinion. Enjoy your car.

pauldana

Air filter:

It is much more beneficial to bring in colder outside air, like the duel snorkel stock unit does then to change air filters. period. that being said... K&N makes a good stock replacement filter, but you got to keep it clean, and correctly oiled.

PeteZO6

The throttle shaft in my original Q-jet wore out the bores in the carb base in the 75K mile range. The major symptom was erratic idle speed. If your carb is otherwise good, do some research and rebush the shaft.

If you MUST get a new carb, Holley makes replacement spread-bore carbs, in both vacuum and mechanical secondary models. Go with one of those and you won't have to change your intake manifold. Stock air filter is probably your best bet too.

If you have your heart set on making a lot of engine mods, then disregard
my advice.


Pete

terry82

best sales job ever .they are so good no fleets use them .they do let in more air ,dirt too.add a k and n filter run it for 1000 miles then have your oil checked by a lab they will tell you to get a new air filter.but if you like it enjoy.

ddawson

As an LS1 guy one trick I use to oiling is to let it sit over night on some news paper.

Any excess oil will run and and get absorbed. Turn the filter a few times to move any pooled oil that got trapped. I also use K&N in everything and I've never had an issue with the MAF getting messed up.

qwank

He probably wants you to put a Holley on it because He doesn't know how to tune a q-jet

resdoggie

It's your car and your money. Put what you want on it. Nothing wrong with a Holley or a QJet. They both give good performance.

mac79vette

Holleys are really good carburetors and work really well and are easy to tune. I have used many Holleys on different vehicles and they always work. I currently have a proform carburetor on my vette because it is based on the Holley but it is billet aluminum so to me better quality and more tunable. It uses Holley tuning parts. As for an air cleaner and as I had posted earlier in this post I am using a stock air cleaner with a K & N filter. This set up proved to make more power over a 14 in open air cleaner with a K&N filter on the dyno. The base of the stock filter will have to be modified to work on the Holley type carb if you have a stock hood.

REELAV8R

I wondered if the K&N filter was all that it said it was as well, so I decided to conduct my own test for air flow.
On my 77 L-48 the air cleaner box has a port on the side for the PCV valve. I disconnected the hose from this port and attatched 12 feet of clear vinyl hose to it.
I then ran the hose out from under the hood to the side window on the passenger side.
I formed a "U" shape on the side window with the hose and taped it on. This gave me about 12" of hose visable from the inside of the car. I filled the U of the hose with blue colored water (blue made it easier to see) and then calibrated one side of the hose in inches with a piece of tape run vertically next to the hose.
So now with the air cleaner lid on a vacuum is drawn on the intake and this is reflected by how far down the tube the water would be drawn. This is vacuum outside the air cleaner element. So it will tell me how much vacuum is experienced through the air cleaner element.
Without any air filter at all I would expect the most vacuum to be shown. I tested it this way and all of the water was drawn into the engine and consumed.
Then I tested with a paper element and very little vacuum was shown on the water level about 4" down the tube.
Then I tried the K&N element. This time all the water was drawn into the engine and consumed.
Conclusion; The K&N air filter represented very little restriction to air flow.

If your air filter is the greatest restriction in the intake tract then that is no different than running a restrictor plate on your intake. Less air= less fuel= less power available.
Certainly at lower rpms or with the secondaries not open a standard paper element would probably not be a restriction. Nor would a restrictive air intake. Smaller air intakes probably would increase velocity to the carb giving it a better vacuum signal at least off idle but at the cost of WOT operation.
I used this same test to determine how much the cold intake design on the 77 was restricting air flow. The stock intake also was a considerable restriction and in fact was the reason that the water was fully drawn into the intake and consumed by the motor. After some modifications to the stock 77 CAI I was able to reduce the total vacuum in the air box to only 1.5" of water depression at WOT.
Best scenario is cold air intake with sufficient Cubic area to not restrict the motor and a K&N air filter in my opinion.

augiedoggy

Please find me one piece of proof that a cai is for gains anything more than 7-8 HP..... I have been unable to find and dyno tests to show anything bigger than this. More show a lot less or an increase.... Sorry to be blunt but theres no way in hell you get 20-30 HP gain from going from a proper clean air filter to a CAI intake setup.

donyue

The link below shows a good test of available air filters available. Looks like the K&N provides better flow and only marginally less filtering capability. Since my C3 is not my daily driver and I would like to get the best performance available then I believe adding the K&N filter is a good choice. JMHO.

http://www.bobistheoilguy.com/airfilter/airtest1.htm

augiedoggy

For the same reason putting an 850 Cfm Carb wouldn't increase power on a stock engine over a properly setup Carb.... there,s not very much loss between the amount of air a regular air filter can flow and the amount that can be utililized through the throttle bodies of the Carb.... yes you can pick up a few HP going from a paper element to say a k&n but its nothing like the marketing people make it out to be.... its like the spark plug fiasco a few years back when everyone thought they could pick up HP from changing the plugs and wires to precious metal plugs and colorful thicker jacket wires ..... not gonna give you anything over new OEM stuff as far as HP. It may have shielding advantages and hold up better with a hotter distributor coil at higher rpms but 90% of the people that buy into the marketing hype never break 4,000rpm in their weekend cruisers.

pauldana

Every 40* temp difference is equal to 1 psi of boost.... i made a CAI that showed a 45* temp difference, and a ram air effect of +.2 psi in the bowl area at 100mph... done properly, a CAI can and will increase HP, help with ping in the summer and run cooler and smother.

augiedoggy

Did you miss where that article clearly states changing the filter on a relatively stock engine and air cleaner will net you little if any performance advantage while decreasing the filtering capability which can equal worn out engine prematurely since more contamination gets in the engine?

pauldana

Both temp gauges hooked up... Same temp reading.....






Now lets go for a run......

42* DIFFERENCE!!!!!!!!

augiedoggy

I argree it can help.... I disagree with anything near 20-30 HP..... even the "air gap" intakes have been proven to offer no temp advantage once the engine comes to full temp.... everything gets so hot the air is heated quite a bit before it reaches the combustion chamber.... I doubt the temps are 40 degrees cooler at that point..... if its true there should be plenty of testing to confirm this right? Where are the results showing 20-30 HP gains from an aftermarket intake over a stock setup? This comes up on every forum I belong to and proof is never found.... I admit I bought into it and added a CAI setup on my truck.... all it did was make it quieter since I don't here the air cleaner sucking air. I also used a k&n filter on my 84 for 13 years with regular maintenance..... the rings were shot at 100,000 miles could the filter have had anything to do with this?

gluvnaa

pauldana,

Thanks for posting the data, but I believe that the sensor that was mounted on the outside of the CAI is too close to the valve cover for a proper reading.

It should be in a location that obtains ambient air with min heat from the engine.

The 65* reading I assume is with the engine cold.

I would be very interested of seeing the following two results.
1. Current setup with car at idle for 5 minutes.
2. Modify outside CAI sensor to be located on top of the air cleaner assembly.

I think that you could also see similar results using a IR sensor by just hitting the valve cover and the top of the carb with the engine running.

Andrew

donyue

Hi augiedoggy, No I didn't miss that information. But in case you didn't read my message my C3 is not a daily driver and it does have a stock engine (427 SBC with 550hp).

I only drive my C3 on average of 5000 kilometers per year if I am lucky. So I am going with the fact that the filtering difference based on how much I use my car versus others that use their vehicles up to 20,000 kilometers per year is going to make the K&N filter right for my car. From the tests and just common sense the K&N filtering capability is not 25% less than any other filter out there. Hope this makes sense.... of course it is only JMHO.

augiedoggy

Without better flowing heads, exhaust, intake and Carb it matters very little how much air is available at the top of the Carb.... it can utilize a marginal amount and that can only stay so cool for so long... you can help by doing other mods to keep temps down in the engine compartment but still the advantage isn't going to be as big as mentioned above... certainly not in a street environment... it it did we would see 20-30 HP gains on a dyno with the air cleaner removed and the hood opened.