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  #16 (permalink)  
Old 04-28-2012, 07:19 PM
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Read this article
http://www.nationaltbucketalliance.c...bs2/carbs2.asp

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  #17 (permalink)  
Old 04-28-2012, 07:37 PM
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  #18 (permalink)  
Old 04-28-2012, 08:04 PM
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Couldn't have found a worse article on tunnel ram carbs if I tried.
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Old 04-28-2012, 08:51 PM
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X2! Lots of this stuff is written by guys who never tried the setup, they just read the naysayers stuff, and it is based on some logic, and decided no one should do it. They're all looking for the "perfect"tune and the tunnel ram set up won't give you that without lots of work, but it will give you lots of fun and reasonable performance if you do it right. Mine works with an automatic and 2800 rpm stall and it will idle in gear with a solid roller in the 240 at .050 neighborhood. Gas mileage might be the best but it starts, runs and looks and sounds GOOD! AND... I'll leave the stoplight with anyone that wants to and be OK, even though it's only a 308 cid SB Ford.
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Old 04-28-2012, 09:29 PM
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Quote:
Originally Posted by ap72
Couldn't have found a worse article on tunnel ram carbs if I tried.
There are more article on this subject. And they all the same. Overcarburetion is the one mistake in tunnel ram setup. If one 600 was made work, What make you think two 600 CFM is going to perform better. BS! Just because you see them at the track does not mean it's works on the street. Half of you guys do not even own a cars with tunnel ram. What make you think you are experts on tunnel ram.
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Old 04-28-2012, 09:43 PM
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im sure two 600 will work, but tell me how 1200cfm is better for steet use on a slight over stock engine vs using 780cfm? To each his own..
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Old 04-29-2012, 08:55 AM
How fast is fast enough?
 
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Quote:
Originally Posted by lg1969
There are more article on this subject. And they all the same. Overcarburetion is the one mistake in tunnel ram setup. If one 600 was made work, What make you think two 600 CFM is going to perform better. BS! Just because you see them at the track does not mean it's works on the street. Half of you guys do not even own a cars with tunnel ram. What make you think you are experts on tunnel ram.

You can't size a carb on a single plane like a carb on a tunnel ram. Its a lot closer to an ir setup where 1200cfm total is about half of what you need. 600's will be fine. A mechanical carb with dual accelerator pumps would be better but the vac secondary can be adequate.

As for being a lot of articles on the subject the internet probably has more false information than true, as a result of anyone being able to publish.
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  #23 (permalink)  
Old 04-29-2012, 12:50 PM
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If this is your theory. It's a poor one. I've been running my setup for 35 years and yes I made mistakes in the past. Installing big carbs to make it run faster and all it did is bog when I floored the gas pedal. And it ran OK if you stay off the secondary. It would bog or lean backfire off line once in a while, or run sluggish. It made a world of a difference when I installed a pair of 390 CFM.

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Old 04-29-2012, 01:39 PM
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Read Dave Emanuel's book about tuning holley carb's , he backs up lg'69's statement about running small carb's !! I'd consider him pretty much an authority.....
dave
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  #25 (permalink)  
Old 04-29-2012, 08:07 PM
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If its a grocery getter motor you are running, then small carbs are fine.

But if you want to make the tunnel ram make the big power it is capable of
small 390cfm carbs will limit its power basicly to that of a good single plane manifold.

On more radical high power street motors with a tunnel ram where you want a real power advantage, you want larger carb cfm.
Getting the carbs dialed in is just a matter of tuning the carbs.

The 600cfm VS carbs will work very very well once dialed in.
Good idle, throttle response etc is just a matter of tuning what you got.
Lower final cost than buying new 390cfm carbs (that will need tuning also)

They will make more power on your 327 than the 390's will.

Idealy you would want some 650-750 DP carbs. But the 600's w VS will get it done.
The Air fuel ratio gauge is a huge help.
Remeber the 600VS caarbs are a universal carb its has a universal fuel calibration out of the box that is not optimized for your engine.

Its is up to you to dial it in to work best on your application.
You can get the tune very sharp. (jets, , sec metering plates pVCR, idle and high speed air bleeds. Idle feed restrictions. secondary opening rate)

The distributor advance curve will need work too.
It will not bog and spit at all, once dialed in.

If a 80% engine volumetric efficiency is all you aspire to achieve, then go for the tiny carbs.

Good fully street able street high performance engines are fully capable of much more than that. Especially with a tunnel ram and the right size carbs for the job.
Which is more than a pairr of 390's or 450's. Even on a 327.

Your 600's just need some dialing in.

Last edited by F-BIRD'88; 04-29-2012 at 08:13 PM.
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  #26 (permalink)  
Old 05-01-2012, 11:11 AM
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Wow I always see this when tunnel rams are even mentioned, you have the poser ( the guy who wants the looks and sound but doesn't care about real power or true potential) arguing with the guy who builds for the true performance of a tunnel ram on the street or track! I don't understand why your arguing!!! You would think if your putting the money into tunnel ramming an engine You would tune it to its potential and still be street-able!! Its like the guy running a dummy blower for looks arguing with a guy running 35# of boost! I mean G, you guys could get better performance from a dual plane single carb, Why are you running tunnel rams ??? All the guy asked was if he could run the carbs he has and he can!!!!

No offense meant (to each his own), But you should ask the thread starter: do you want to pretend or do you want to walk the walk & talk the talk !!!

Jester
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Old 05-01-2012, 03:13 PM
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Quote:
Originally Posted by painted jester
Wow I always see this when tunnel rams are even mentioned, you have the poser ( the guy who wants the looks and sound but doesn't care about real power or true potential) arguing with the guy who builds for the true performance of a tunnel ram on the street or track! I don't understand why your arguing!!! You would think if your putting the money into tunnel ramming an engine You would tune it to its potential and still be street-able!! Its like the guy running a dummy blower for looks arguing with a guy running 35# of boost! I mean G, you guys could get better performance from a dual plane single carb, Why are you running tunnel rams ??? All the guy asked was if he could run the carbs he has and he can!!!!

No offense meant (to each his own), But you should ask the thread starter: do you want to pretend or do you want to walk the walk & talk the talk !!!

Jester
Why people like to be different? Because it's there. I have seen fuel injectors with stacks coming threw the hood, and when you take a close look, he's running a 4 barrel. He did it for looks. You see a single Quad setup with dual plane, you see them all yon. There all the same. Tunnel ram is not just for looks. This is no lie, I raced a 69 Chevelle 396/375 with 4 speed and 4:10 gears and I beat him. And that's with a 355sbc on a tunnel ram with a pair of 390 carbs, 3 speed automatic and 410 gears, .

Last edited by lg1969; 05-01-2012 at 03:38 PM.
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  #28 (permalink)  
Old 05-02-2012, 01:33 PM
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The cfm formula does not work for ram intakes single quad rams or tunnel rams its designed to figure the cfm for an engines basic capacity to move air in and out with vacuum alone. When running a ram (Ram air because its ramming air into your cylinders) the ram effect at rpm (increased air velocity) in the runners creates pressure at the intake valve and when the valve opens the pressure pushes the fuel air charge into the cylinders thus increasing the volume of air in that cylinder beyond its basic capacity! The longer and straighter the runner the higher the velocity and the more air is forced into the cylinder beyond the engines ability to to bring in the air fuel charge with vacuum alone. So the tunnel rammed engine at 6000 rpm can flow 1400 or more cfm! a good 750 more cfm then a lowrize single 4 barrel intake on a 350 chevy built equally in the same car. Then when you utilize small carbs you are actually cutting down the fuel air volume and ram effect of the intake (killing the hp and torque potential). Add velocity stacks or a scoop and cfm increases even more on the same 350 engine! The cfm formula does not work in a tunnel ram scenario!

I read the article that was posted earlier from national t bucket alliance and I think its gibberish when applied to tunnel rams!!! I also have set up tunnels for customers with small carbs and if tuned right will work on the street but Ive also set up 8 cylinder engines to run on 6 cylinders (Cadillac for example) during the gas crunch in the 70's at the dealers! And to me it amounts to the same thing it works but your hp and torque are gone!!!! Why buy the Cady? Why buy the tunnel! Unless you dont care about the benefits? Its just never made sense to me!

Firebird or other members can probably elaborate on this and explain it better then I did!! this is all from memory when I was in engineering classes in the 60's so I might have left a few things out!

Whether your running for power or running for looks have fun and be careful on the street or track

Chris
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Old 05-02-2012, 02:07 PM
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Thanks Chris! Not sure I completely understand it but sounds good... .

Just to clarify to everyone. This intake and carb setup was given to me... I have no money in it. I also have no money in the motor other than the cost of the actual car. The idea is to install it and have fun while I am collecting parts for my BB build. Building the BB now or anytime soon is not feasible based on all the other work that needs to be done. I am wanting to do this for fun not all out performance. It is not intended to be all out performance but more of as much performance as I can get realizing the limitations.

For all the "Why do it's" my answer is "why not?" But thanks all for the input. I have learned a great deal and may transfer this to the BB build which I know will handle it.

Wade
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  #30 (permalink)  
Old 05-02-2012, 02:47 PM
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The Raming effect is only 2% to 5% increase. not 50% increase. Where a typical 350 flow 608 cfm to 1200cfm is pure bunck. If you have an article that will back you proof, Show it.
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