Sdriche
Well-Known Member
I’m trying to verify the CFM for my current carb which is a carter c-6090. Ideally I’d like more acceleration ….from what I can tell it’s a fairly stock 360 with a performance intake. Anyone know the CFM ? Ty
360 carb question - Carter c-6090
- Thread starter Sdriche
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6090 C-4-TQ 72 400 A/T Non A.I.R (RR, Charger, Fury, Polara, Monaco, Coronet And Satellite
should be big enough(might be running rich)//love those TQ//get those secondaries adjusted right and hang on !!
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AJ/FormS
68 Formua-S fastback clone 367/A833/GVod/3.55s
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Under what circumstances do you "Want " more power.
If you already have a 4bbl;
> Even a 500, is good to 5500 or more , on a stock 360.
> A bigger carb is not gonna be worth anything to brag about , and not worth anything at all, below say 3500/4000 rpm.
> So if you want more acceleration from a standing stop or slow-roll, a bigger carb is NOT your answer.
> the very modest power-increase of a bigger carb will not show up until much higher rpm and not much until wind-resistance gets up ..... like when drag-racing.
If you already have a 4bbl;
> Even a 500, is good to 5500 or more , on a stock 360.
> A bigger carb is not gonna be worth anything to brag about , and not worth anything at all, below say 3500/4000 rpm.
> So if you want more acceleration from a standing stop or slow-roll, a bigger carb is NOT your answer.
> the very modest power-increase of a bigger carb will not show up until much higher rpm and not much until wind-resistance gets up ..... like when drag-racing.
Sdriche
Well-Known Member
You answered my question so thanks. Yes was looking for more off the line acceleration.
junkyardhero
Well-Known Member
rear end gears should take care of that no problem. add a decent stall converter and double the fun.
but it shouldn't be that bad with a 360 and an aftermarket intake with a 4V unless the tune is crap or you've got like 2.45 rear gears with 28" tires and ragged out automatic
Sdriche
Well-Known Member
How do I check WOT ? Are you saying when the accelerator is down does it open all the way? Car has a 8 3/4 rear with 3:23 gears 15" tires and stock stall.
To check that the carb is fully opening [ Wide Open Throttle ].
On the sec throttle shaft, drivers side, there is roll pin. When you get WOT, that pin hits a stop on the carb base. Attach throttle linkage & push acc pedal down to check the above. Can usually see from the driver's seat.
On the sec throttle shaft, drivers side, there is roll pin. When you get WOT, that pin hits a stop on the carb base. Attach throttle linkage & push acc pedal down to check the above. Can usually see from the driver's seat.
Sdriche
Well-Known Member
i thought this was a really good chart that reinforced what was shared earlier. On a 360 stock engine, you don't need higher CFM until you exceed 5k RPMs. This was helpful.
That chart is not relevant in the real world, especially with an adjustable secondary air valve ( AVS, TQ, Q-Jet, Street demon) carb. A TQ will run better than most any carb, followed by Q-Jet when done right. I've loaned a 750 cfm 440 Carter AVS carb a couple times on engines as small as a 289 and it performed so well they did not want to take it off. That 6090s TQ should be 800 to 850 cfm and that was the size TQ for OEM HP 360s. I run that carb on my 383 Formula S. Loosen the secondary spring a little at a time until you get a bog, then tighten it back till it goes away. What gears are you running.
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Sdriche
Well-Known Member
3:23
Sorry, that chart is as relevant today as the day it was published. It is chart version of the graphical version published in the original Mike Urich Holley book. What the chart doesn't say [ maybe it just wasn't quoted above ] is that the numbers are based on 100% VE.
Sorry, I'm not going to run a 500 cfm carb on my 273. I've run a 750 cfm TQ on it and not even close to the same.
I would try tuning your car. I assume an auto trans? Adjust the kickdown on the trans and adjust the Secondary air valve to open as soon as the engine can take it. Make sure the secondaries are opening and all the way.
Sdriche
Well-Known Member
I appreciate all the advice and have my path forward. Its a 727 trans so I'll check kickdown, ensure the secondary's are opening fully and aggressively. I'll report back
If you want to see the stupidity of using a carb that is too big for the engine, look at the 340 Dyno test at Nick's garage, 4 days ago. 800 Edel AVS, 750 Edel AFB & 800 TQ tested. The AFB made more tq & hp.
Nick would have to tune each carb to the nth degree for that test to have an real validity. The results from this one test session are not definitive proof of anything .
What the test showed was that the extra airflow from two larger carbs lost power & torque to the smaller carb. The AVS also had annular boosters, which normally increase power.
The engine will only draw the air that it needs; that is what the chart in post #9 is for, to select the correct size carb.
You could put a dominator on a slant six & it will run, but the very low air speed through the large venturiis is going to produce a very poor signal, poor fuel atomisation & poor performance. Atomisation is the key.
The engine will only draw the air that it needs; that is what the chart in post #9 is for, to select the correct size carb.
You could put a dominator on a slant six & it will run, but the very low air speed through the large venturiis is going to produce a very poor signal, poor fuel atomisation & poor performance. Atomisation is the key.
That is why the TQ and Q-jet are king. I don't need a video, I tried so many combinations over the years on so many engines including the minuscule 273. Use the chart if youy want to run the primitive Holley, but I've run a 750 cfm TQ and 70 440 AVS on small motors and they were game changers. If you want a mediocre engine, by all means use the chart.
It's pretty easy for one to find a test that matches ones own opinion. Here's a test that shows them big ole dumb Holley Dp's beating up on all the Carter types : Moparts on the Web - Main Index
Well, I was on the Offenhauser site trying to figure out if I can use a manifold. Same chart, but when you actually read the instructions, those numbers are minimum cfm recommendations. Page 14 of their catalog.
No argument from me that the TQ & QJ are 'king'.....but they can be overkill on small engines that do not require the airflow they can provide.
'Game changer' or 'runs very well' is not the same as 'best'. Best encompasses everywhere from idle to max rpm, not just the peak hp. This was shown in Nicks test where the 750 carb made the same hp as the 800, but made about 15 ft/lbs more mid range tq. The engine didn't need the extra 50 cfm & it hurt in the mid range. I know which carb I would rather use......
Another example is carbs that have annular boosters available. They usually make a little more power than their non-annular cousins. However, the boosters are physically larger & reduce airflow slightly. So less airflow, more power.
'Game changer' or 'runs very well' is not the same as 'best'. Best encompasses everywhere from idle to max rpm, not just the peak hp. This was shown in Nicks test where the 750 carb made the same hp as the 800, but made about 15 ft/lbs more mid range tq. The engine didn't need the extra 50 cfm & it hurt in the mid range. I know which carb I would rather use......
Another example is carbs that have annular boosters available. They usually make a little more power than their non-annular cousins. However, the boosters are physically larger & reduce airflow slightly. So less airflow, more power.
I've run everything on a 273 imaginable on the street. It does not get much smaller. The "71" or "72" 340 TQ was tops in power and mpg. And that is running solid cams from 284 duration to the minuscule Commando cam. The 340 TQ was always the top.
Sdriche
Well-Known Member
So the carb secondaries are only opening 3/4 of the way. The end of the secondary rod is physically hitting the choke spring. Any way to adjust this?
There should be a lockout on a stock carb that prevents the secs from opening until the choke is fully open [ blade is vertical ]. If not using the choke, wire it in the fully vert position & secs should work.
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