tunnel ram
12-14-2004, 03:43 AM
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Car: 1987 iroc z
Engine: 355 dart platinum 215cc heads
Transmission: <<BLOWN UP TH400>>
Axle/Gears: 10 bolt 4.11's
tunnel ram
i was thinking about a tunnel ram whats the difference between that and a regular intake manifold. thanks
and would it be better
and would it be better 
12-14-2004, 04:07 AM
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Car: 88 iroc vert
on a tunnel ram, the intake runners take a more direct(straight) path into the heads.
its usually used for real high RPM's 6500+.(strip)
unless ur gonna see 6500+, dont think about it. maybe good for show? not street.
as u can see, it sits a hell of alot higher too!
my opinion, dont bother with em, unless ur gonna be racing it.
its usually used for real high RPM's 6500+.(strip)
unless ur gonna see 6500+, dont think about it. maybe good for show? not street.
as u can see, it sits a hell of alot higher too!
my opinion, dont bother with em, unless ur gonna be racing it.
Last edited by Gecz28; 12-14-2004 at 04:09 AM.
12-14-2004, 01:06 PM
#3
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A tunnel ran uses two four barrel carbs.
A tunnel ran is simular to a single plane manifold like a Vic Jr.
Because of the longer runners and straight shot at the intake port a tunnel ram will make some more horsepower and torque than a single plane manifold.
A tunnel ram can be a very streetable intake manifold. The secret to a successfull
street tunnel ran setup is to use small cfm carbs. (The airflow requirements of a engine remain basicly the same reguardless of the number of carbs)
Two 450cfm holleys or two 500cfm edelbrock carbs work well.
Either carb type will need carefull tuning to match a tunnel ran to a street motor.
main jetting, idle metering,metering rods, accelerator pump nozzles and linkage, choke operation and throttle alignment setup will be nessessary.
A wideband AFR meter would be a great tool to dial in the carbs for a tunnel ram. A few hours on a chassis dyno would allow you to really dial it in.
Some people will tell you tunnel ram setup will tend to back fire on startup.
Notso, if you use the right startup method.
Because of the large internal volume of a tunnel ram's plenum and runners you need extra fuel on startup to avoid a leanout ( backfire) simular to a roots blower. Pump the throttles a few times to prime the manifold with fuel and leave the throttles closed. Crank the motor over and it will start right away.
A working choke goes a long way to helping during warm up.
The long upright runners take a little longer to warm up on a tunnel ram than a single 4bble intake. Give it some time to warm up to operating temp before driving.
For the street you would want to avoid any type of "racing carbs" like holley 660 centersquirters or predator carbs.
Remember, use two small cfm carbs.
tech article
A tunnel ran is simular to a single plane manifold like a Vic Jr.
Because of the longer runners and straight shot at the intake port a tunnel ram will make some more horsepower and torque than a single plane manifold.
A tunnel ram can be a very streetable intake manifold. The secret to a successfull
street tunnel ran setup is to use small cfm carbs. (The airflow requirements of a engine remain basicly the same reguardless of the number of carbs)
Two 450cfm holleys or two 500cfm edelbrock carbs work well.
Either carb type will need carefull tuning to match a tunnel ran to a street motor.
main jetting, idle metering,metering rods, accelerator pump nozzles and linkage, choke operation and throttle alignment setup will be nessessary.
A wideband AFR meter would be a great tool to dial in the carbs for a tunnel ram. A few hours on a chassis dyno would allow you to really dial it in.
Some people will tell you tunnel ram setup will tend to back fire on startup.
Notso, if you use the right startup method.
Because of the large internal volume of a tunnel ram's plenum and runners you need extra fuel on startup to avoid a leanout ( backfire) simular to a roots blower. Pump the throttles a few times to prime the manifold with fuel and leave the throttles closed. Crank the motor over and it will start right away.
A working choke goes a long way to helping during warm up.
The long upright runners take a little longer to warm up on a tunnel ram than a single 4bble intake. Give it some time to warm up to operating temp before driving.
For the street you would want to avoid any type of "racing carbs" like holley 660 centersquirters or predator carbs.
Remember, use two small cfm carbs.
tech article
Last edited by F-BIRD'88; 12-14-2004 at 01:09 PM.
12-15-2004, 09:34 AM
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Car: 83 Z28
Engine: vortec 305 for now
Transmission: 5 speed
Yes I too have used tunnel rams on the street behind a couple of pro-street camaros, and a vette. Carb size is the secret to making them work, also in one application I used Carter AFB's (now edelbrock) carbs because to some extent they self meter, and are a lot less work to keep tuned. The other benefit is that they don't leak fuel all down the polished TR.
That being said, A TR can be made to work on the street, but that doesn't mean you should. I love 2X4bbl setups, they sound great, but, you need to have then engine components and gear ratio to back that up. IMHO I would recomend the new edelbrock 2x4 intake with their carbs, it will fit under the hood and is a lot more manageable.
My favorite set up was 2x4bbl edelbrock intake with Carter afb carbs, ported and polished fuelie heads on a small journal .030 327. It had TRW forged pistons @ 10-1CR and an 1st design offroad Z28 cam, 4speed and a 5.13 12bolt rear.
Clearly, this is not something a lot of people would be comfortable with on the street.
That being said, A TR can be made to work on the street, but that doesn't mean you should. I love 2X4bbl setups, they sound great, but, you need to have then engine components and gear ratio to back that up. IMHO I would recomend the new edelbrock 2x4 intake with their carbs, it will fit under the hood and is a lot more manageable.
My favorite set up was 2x4bbl edelbrock intake with Carter afb carbs, ported and polished fuelie heads on a small journal .030 327. It had TRW forged pistons @ 10-1CR and an 1st design offroad Z28 cam, 4speed and a 5.13 12bolt rear.
Clearly, this is not something a lot of people would be comfortable with on the street.
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