To tunnel ram or not to tunnel ram - Page 2 - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Engine
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #16 (permalink)  
Old 02-16-2012, 10:22 PM
maverickmechanic13's Avatar
I'll have a beer with that.
 

Last journal entry: My Trans Am
Last photo:
Join Date: Feb 2012
Location: Cleveland, OH
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
upon digging, i found the exact specs on my motor:
Cam: SUM-9000 (from a long ime ago) 454 lift intake and exhaust, 216/ 216 int/exh @ .50 adv dur 272, LSA 112; Springs 130 @seat, 300 open; 15.7 cc pistons, trick flow heads (31400001) 170cc intake, 63 cc chambers. Its an old summit crate, that they had advertised as a 360hp motor.

Also, i fouund this info on another forum. A few different articles that illustrate the points mentioned above:

http://www.stevesnovasite.com/forums...p/t-43076.html

thank you for all your input huys, its awesome. It seems that tunnel rams still have a few fans out there : )

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #17 (permalink)  
Old 02-16-2012, 10:24 PM
4 Jaw Chuck's Avatar
Hotrodders.com Moderator
 
Last photo:
Join Date: Mar 2002
Location: Manitoba, Canada
Age: 46
Posts: 4,972
Wiki Edits: 0

Thanks: 2
Thanked 89 Times in 72 Posts
I've had the same experience as lg1969, put too much carb on a tunnel ram and you basically lose all metering signal at the carb which requires huge squirters to make up the hole.

I think the twin 390 cfm carbs is the hot street setup for any small block, twin 650 double pumper spreadbores for a big block...but you need a cam/engine combo that can make power in the top end of the rpm range.

Sorry F-Bird, I've had the exact opposite experience than what you recommend. The reason why big carbs aren't the ticket is because each cylinder breathes through both carbs, so when you double the number of primary carb bores to breathe through, your metering signal goes to zero.

Best combo I've seen in real life was a 351 Cleveland running two 650 Holley spreadbore carbs, it peaked at 7500 rpm with shifts at 8000. If anything it was overcarbed but the smaller primary's of the spreadbore carbs helped it out of the hole...it still needed 5.13 gears to move the car on the dragstrip with a 3200 pd car.

When in doubt, consult the manufacturer of the manifold you want to run...they will give you good advice for the cubic size and cam you want to run. Just realize for good all around performance you would be better off running an open plane manifold, tunnel rams are old school and really a stop gap measure until they came up with better single plane designs...they are not superior.

Look nice though!
__________________
Outlawed tunes from outlawed pipes
Reply With Quote Quick reply to this message
  #18 (permalink)  
Old 02-17-2012, 04:36 AM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,134
Wiki Edits: 0

Thanks: 4
Thanked 374 Times in 368 Posts
Spreadbores are not the best for a tunnel ram nor are they recomended at all.
You want carbs with equal or near equal pri and sec venturii sizes on a tunnel ram.

You many have seen a car with spreadbores and it may have made it to the end of the 1/4 mile but it will run better with two square bore carbs.
yup 650-750 cfm for a hot 350 w a tunnel ram and yup you got to rev it up to use all the power in a 1/4 mile and you got to gear it to move it quick.

Tunnel rams are not a stop gap mainiffold to a single plane. Tunnel rams make more power than a single plane ever will.
The most poerfull american V8 carbed motors use a tunnel ram and two carbs

Pro Stock Pro Mod. You will never compete agaisnt these induction systems with a single carb single plane manifold.
A street tunnel ram + two correctly sized and tuned carbs will make more power than any single plane w single carb.

But you will cripple it if you use small cfm carbs. You will cripple it with a tiny cam. You will cripple it with a restrictive exhaust system.
You will limit how much power it can make if you pair it with a poor cylinder head.

Power wise a tunnel ram cannot be beat. On a naturally asparated V8. They are also very driveable when set up correctly. One thing that they do need is a longer warm up time to get some heat and good vapourization in the manifold runners and plenum.
This is a function of the distance of the carbs height from the motor, not the size of the carbs.
Takes a few minutes more to warm up. Proper ignition timing and cold engine idle speed during warm up avoids most of the common issues.

You will not achieve maximum performance using small cfm carbs on a tunnel ram. You will negate most of any gain over a simgle plane manifold if you cripptle a tunnel ram with small carbs selected beased on typical carb size selection rules.

Even the most powerfull fuel injection V8 racing manifolds are basicly tunnel .rams.
Cross ram manifods are basicly folded tunnel rams. They like and use big carbs too. The 1968 69 302 Z/28 cross ram motor did not use tiny 390cfm carbs or spreadbores.

Read the Anvil article The whole article and look at the dyno comparision between the single plane+ single carb and the tunnel ram with 650's.

By your theory on carb size cfm requirments the motor should not have made any more power with two 650's.

The motors horsepower and torque curves from the dyno test say different.
This is not an anomaly . it is typical on this level of motor build.
A more radical build will see and even larger power gain.
Not only does it make a lot more peak power, it makes more power and torque eerywhere thruout the whole usefull power band, which is quite broad. The use full power band of the tunnel rammed motor is typically wider and extended than a single plane and more powerfull at all points not just at the peak.
Thats why that tunnel rammed 351 could rev up and make usefull power to 8000 rpm. Spread bores are not the best choice.
Small cfm carbs will severly limit the top end power.

The typical carb sizing formula CID x RPM /3456 = carb cfm does not work on a hi performance engine with a tunnel ram. If you want it to actually make power.

Last edited by F-BIRD'88; 02-17-2012 at 04:59 AM.
Reply With Quote Quick reply to this message
  #19 (permalink)  
Old 02-17-2012, 04:50 AM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,134
Wiki Edits: 0

Thanks: 4
Thanked 374 Times in 368 Posts
The summit 216 -216 .454 .454 112 cam is very mild for a tunnel ram. It will run but don;t expect big power using that little cam.

Small cam,, small carbs = limited power from a tunnel ram.

If all you want is the look, go for it.

Tunnel Ram's are not Old School at all. They are and still are the most powerfull intake manifolds.
Most all of the wild modern EFI manifolds you see on modern V8's and V6's are variations on a tunnel ram.
EG : Corvette LT-1 LT-4 ZR-1 ( LT-5 ) all the LS-1 LS-6 LS3 Z06 etc series corvette V8's, L31 vortec 5.7 350 Ram Jet crate motors. Chrysler Hemi,
All these induction systems are just tunnel rams in various configurations with EFI. Even my lowly daily driver Malibu 3.1L V6 induction system is a tunnel ram
design.
Your experience with tunnel rams and more powerfull hi perf engines is obviously limited. Need some schooling in that subject.

Last edited by F-BIRD'88; 02-17-2012 at 05:16 AM.
Reply With Quote Quick reply to this message
  #20 (permalink)  
Old 02-17-2012, 05:35 AM
F-BIRD'88's Avatar
Yada Yada Yada
 
Last photo:
Join Date: Oct 2005
Location: Ontario, Canada
Posts: 9,134
Wiki Edits: 0

Thanks: 4
Thanked 374 Times in 368 Posts
Here is the dyno test comparing the tunnel ram + 650's to a single plane single carb manifold. When the theory don;t fit the results, fix the theory.
Attached Thumbnails
Click image for larger version

Name:	tunnel ram dynotest1.jpg
Views:	412
Size:	89.5 KB
ID:	63034  
Reply With Quote Quick reply to this message
  #21 (permalink)  
Old 02-17-2012, 10:01 AM
maverickmechanic13's Avatar
I'll have a beer with that.
 

Last journal entry: My Trans Am
Last photo:
Join Date: Feb 2012
Location: Cleveland, OH
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
So f-bird, what would you suggest i run cam-wise? I already have a msd 6al box with an msd distributor, longtube flowmaster (open) headers. Like i previously stated, i do not have a converter or gears yet, so i will purchase accordingly. I am building a transmission for it at them moment so ive got time to play with the motor.
Reply With Quote Quick reply to this message
  #22 (permalink)  
Old 02-17-2012, 01:52 PM
painted jester's Avatar
TAKE A KID TO A CAR SHOW
 

Last journal entry: mopar hump back
Last photo:
Join Date: Jan 2011
Location: Central Michigan
Age: 68
Posts: 1,837
Wiki Edits: 0

Thanks: 103
Thanked 290 Times in 238 Posts
I read all this,this morning fire bird is on point. I run 2 450s on the street mainly because my wife drives it a lot for just cruising! But if I want more out of the tunnel ram to fool around a little on the street I go to 650s and at the track I bolt on 2 750s to bring it alive! I never heard of anyone running spread bores on a tunnel ram??

Any one can set it up however they want it might seem to run fine and operate well and if your happy with that fine! But you'll never Know what the true potential of a tunnel ram is! The smell of gas the big bogs etc,etc. Is all in the tuning !! None of my carbs have choke housings, all are mechanical secondary's, the 650s & 750s are double pumpers ,my eng's a 355 cu. in. 4 bolt main, forged flat top pistons, I run a comp cam CS 292h-10 (gross lift 501, 106 degree center line, @ .050" 244 I 244 E duration, I install my cams advanced because I run a timing chain and with initial stretch after installing of new chain the cam is straight up the chain I always use is about 3 degrees stretch (other chains I dont know) If I ran gear drive Id put em in straight up, I run 1.5-1 rockers on intakes & 1.6-1 exhaust, 11to1 static comp, 62 cc'ed heads including plug cc , B&M 2500 advertized stall ( actual brake stalls at 2700 & flash stalls at 3300 ) 3.73 posi, B&M 500 hp rated trans, in a 77 vette. This combination works well for me! If I was to put in more track time Id run a much bigger cam (solids) installed straight up, and probably 4.88 gears. I wouldn't run a cam any smaller then the 292 with a tunnel ram (but thats my opinion). I only go to a track a couple of times a year if that, I try to keep it in the 12s or I have to add roll bar, drag loop trans blanket etc if it hits 11s ! Thats just my set up its built for fun (and it is )

When you go to pick out a stall converter! Some company's advertize brake stall and some advertize flash stall !!! Make sure you call the company that builds the converter before you order it and find out the actual stall for your combination. you will need the weight of the car with driver, the build of the engine, the trans ratios, rear end ratio, tire size and sometimes the elevation of the track you run at (stall speed drops at higher elevations not because of the converter but because of air fuel mixture & its affect on torque)

As for your cam, and your set up, fire bird can probably help more then I can! Im old school and Im getting older He sound's like he is more knowledgeable on the new cams and set ups then I am. I build my cars for speed!! Id talk about it but this thread would get dumped. Guys that stay off the throttle & just run tunnels for looks more power to you. But if you want a real adrenalin rush build it right!! And youll have the devil ridden shot gun !!!! Thats written on the doors of my car!

Jester
Reply With Quote Quick reply to this message
  #23 (permalink)  
Old 02-17-2012, 03:17 PM
lg1969's Avatar
Google "Tunnel Ram 406"
 
Last photo:
Join Date: Oct 2007
Location: Bohemia, L.I.N.Y.
Age: 64
Posts: 1,059
Wiki Edits: 0

Thanks: 1
Thanked 21 Times in 18 Posts
F-bird, You seem to know a lot about T-ram. Do you build a T-ram motor before using two 750CFM carbs?
Reply With Quote Quick reply to this message
  #24 (permalink)  
Old 02-17-2012, 03:21 PM
prostreet6t9's Avatar
Differential/Driveline
 
Last photo:
Join Date: Sep 2008
Location: oregon
Age: 51
Posts: 1,724
Wiki Edits: 0

Thanks: 8
Thanked 40 Times in 37 Posts
OP: It would be wise to listen to 4Jawchuck on this one. With your "current" combo you DONT have the motor to support that much Carb or that big of a stall Converter. With a milder motor you dont just put 2 750's on and expect a killer set up. Another point.. You dont install a 5k stall on a mild engine and expect great performance.

2-390's (780CFM) is plenty for a mild street set up.

I run a 5500 stall and a 1050 cfm Dominator on a 14-1 BBC. Camshaft is .715 lift.. I just Cant imagine you needing more carb than my motor.
Reply With Quote Quick reply to this message
  #25 (permalink)  
Old 02-17-2012, 03:24 PM
maverickmechanic13's Avatar
I'll have a beer with that.
 

Last journal entry: My Trans Am
Last photo:
Join Date: Feb 2012
Location: Cleveland, OH
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
Jester, that cam you mentioned seems like a reasonable candidate. Whe i ran the twin 450s on my motor, they were never tuned. Simply pulled out of the boxes and bolted on, motor fired up and ran decent. There was no work done to them what so ever, and they still ran pretty good. I had a total of maybe 6-8 hours on that motor, but it didnt foul out the plugs. That surprised me since i thought the motor was over carbed (900cfm between the two carbs) and it was puking fuel in the motor; it seemed to run somewhat decent, with what i already had, but a lot of people told to ditch the tunnel ram ideea, and everyone i asked had no clue about t-rams.
Reply With Quote Quick reply to this message
  #26 (permalink)  
Old 02-17-2012, 03:34 PM
lg1969's Avatar
Google "Tunnel Ram 406"
 
Last photo:
Join Date: Oct 2007
Location: Bohemia, L.I.N.Y.
Age: 64
Posts: 1,059
Wiki Edits: 0

Thanks: 1
Thanked 21 Times in 18 Posts
maverickmechanic13, There is nothing wrong about the setup, Holley 450's were really made to work with manual tranny where you can bring the rev's up and drop the clutch. Automatic takes fine tunnig to make it work. VS carb's works better on automatic tranny. It know's when the secondary will open when it needs it. You will not bog when you hammer the gas pedal.

Last edited by lg1969; 02-17-2012 at 03:39 PM.
Reply With Quote Quick reply to this message
  #27 (permalink)  
Old 02-17-2012, 03:37 PM
maverickmechanic13's Avatar
I'll have a beer with that.
 

Last journal entry: My Trans Am
Last photo:
Join Date: Feb 2012
Location: Cleveland, OH
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
VS Carbs? Pardon my ignorance but what are those?
Reply With Quote Quick reply to this message
  #28 (permalink)  
Old 02-17-2012, 03:41 PM
lg1969's Avatar
Google "Tunnel Ram 406"
 
Last photo:
Join Date: Oct 2007
Location: Bohemia, L.I.N.Y.
Age: 64
Posts: 1,059
Wiki Edits: 0

Thanks: 1
Thanked 21 Times in 18 Posts
Vacuum secondary carb. That is what Holley 390's are.
http://www.allcarbs.com/detail.php?p...&ctgn=71&stt=5

Last edited by lg1969; 02-17-2012 at 03:53 PM.
Reply With Quote Quick reply to this message
  #29 (permalink)  
Old 02-17-2012, 05:06 PM
maverickmechanic13's Avatar
I'll have a beer with that.
 

Last journal entry: My Trans Am
Last photo:
Join Date: Feb 2012
Location: Cleveland, OH
Posts: 53
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
What's so different about these carbs when compared to a set of of the regular 8007s? In other words if I got two 8007s what do I have to modify on them to make them t-ram friendly?
Reply With Quote Quick reply to this message
  #30 (permalink)  
Old 02-17-2012, 05:20 PM
lg1969's Avatar
Google "Tunnel Ram 406"
 
Last photo:
Join Date: Oct 2007
Location: Bohemia, L.I.N.Y.
Age: 64
Posts: 1,059
Wiki Edits: 0

Thanks: 1
Thanked 21 Times in 18 Posts
They have a balance line for uniform secondary operation. It also has a quick change cover to change the springs. A standard 8007 does not have that option.
You can also get it for less on E-bay.

Last edited by lg1969; 02-17-2012 at 05:26 PM.
Reply With Quote Quick reply to this message

Recent Engine posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last name), your email address and other required details in the form below.
User Name:
If you do not want to register, fill this field only and the name will be used as user name for your post.
Password
Please enter a password for your user account. Note that passwords are case-sensitive.
Password:
Confirm Password:
Email Address
Please enter a valid email address for yourself.
Email Address:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

Posting Rules
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tunnel Ram 454 rambler454 Engine 10 02-02-2012 05:07 PM
Help!! Sbc Tunnel Ram forkliftdr Engine 5 05-21-2011 06:34 AM
Tunnel Ram 1bay95west0 Engine 2 04-04-2011 04:10 PM
Tunnel Ram 69 chevelle SS Engine 2 08-07-2003 09:06 PM
How to -Tunnel Ram sedan_dad Hotrodders' Lounge 0 01-20-2003 09:15 AM


All times are GMT -6. The time now is 04:07 AM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.