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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310003
05/06/09 02:04 PM
05/06/09 02:04 PM
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Joined: Jun 2003
Posts: 9,225
Charleston
sixpackgut
Drag Week Mod Champion
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Drag Week Mod Champion
Joined: Jun 2003
Posts: 9,225
Charleston
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i would think that is a lean condition causing the surging. you probably have just a few cylinders goin lean under cruise conditions.
my jetting on my tunnel ram is all over the place to get fuel where its needed and vice versa.
Gen 3 power 6.22@110, 9.85@135
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performance only racing, CRT, ultimate converter, superior design concepts, ThumperCarbs
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: sixpackgut]
#310004
05/06/09 02:14 PM
05/06/09 02:14 PM
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Joined: Nov 2003
Posts: 6,293
Rock Springs
Bob_Coomer
master
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master
Joined: Nov 2003
Posts: 6,293
Rock Springs
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I assume you read the literature out of the old MP engine books, they show some pop cycle stock damns etc......If not, I wouldn't care a bit to scan them up for you.
Which Cross ram are we talking about exactly?
[color:"red"]65 Hemi Belvedere coming soon [/color]
[color:"#00FF00"]557" Indy engine 1.07 60ft 144mph in the 8th 2100 lbs package [/color]
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: Bob_Coomer]
#310005
05/06/09 02:32 PM
05/06/09 02:32 PM
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Joined: Jan 2003
Posts: 4,573
...gently down the stream
LAR_414
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OP
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I have an intake that almost nobody has messed with.....and I like it that way  It's a STR-12 for a smallblock. I've done the only "known" modifications with dams for better fuel distribution. I have an a/f meter (LM-1). I have bungs in both sides of the exhaust. Based on the readings / and the modifications / and the plug readings, everything is good to go for A/F and carbs. I've got this think tuned well. The problem with bucking and kicking is under 1700rpm or so in any gear. This started when I went from a sluch box to a 4 speed. It's not the distrib curve or anything mechanical. Might be the cam, but I'm thinking of trying to reduce the plenum volume to see if it's a low speed air issue inside the intake.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310006
05/06/09 03:04 PM
05/06/09 03:04 PM
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Anonymous
Unregistered
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Anonymous
Unregistered
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Like Bob said the Mopar racing Guide shows the popsikle stick resin dams...They are for more mid to high range power for Drag racing, mainly stick cars. 
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310010
05/07/09 08:26 AM
05/07/09 08:26 AM
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Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
S/ST 3040
master
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master
Joined: Jul 2006
Posts: 4,595
On the south side of Nowhere
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Again, I'd say you're trying to make the intake do something it was never designed for. A lot of plenum volume, probably short runners, 2 4-bbl carburetors, direct drive and no RPM = crappy carb signal/low velocity. I'd say, there isn't enough activity going on in there to keep the fuel atomized and is falling out of suspension. If you get this sorted out, you will probably solve it yourself after screwing with it for a long time.  Good Luck.........Just be glad it's not a 340.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310011
05/07/09 08:40 AM
05/07/09 08:40 AM
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Joined: Jul 2005
Posts: 428
wappinger falls new york
Jimi_Vignogna
mopar
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mopar
Joined: Jul 2005
Posts: 428
wappinger falls new york
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Quote:
I'm looking for some info and possibly pictures of work done inside of crossrams. I may try playing with the insides of mine some more to get out this bucking / kicking / surging that I get in gear below 1700rpm or so. I may try to reduce the overall plenum volume but still have a crossover inside.
Looking for ideas. Maybe even make an adjustible volume via a slide or something, that I can quickly adjust by removing one carb, adjust, re-install carb.
how is your distributor set up? the advance curve has to be right on for large plenum multi carb apps.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: Jimi_Vignogna]
#310012
05/07/09 08:47 AM
05/07/09 08:47 AM
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Joined: Mar 2003
Posts: 9,099
Rogue River, OR
Jeremiah
master
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master
Joined: Mar 2003
Posts: 9,099
Rogue River, OR
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Quote:
Quote:
I'm looking for some info and possibly pictures of work done inside of crossrams. I may try playing with the insides of mine some more to get out this bucking / kicking / surging that I get in gear below 1700rpm or so. I may try to reduce the overall plenum volume but still have a crossover inside.
Looking for ideas. Maybe even make an adjustible volume via a slide or something, that I can quickly adjust by removing one carb, adjust, re-install carb.
how is your distributor set up? the advance curve has to be right on for large plenum multi carb apps.
I for one would be interested in hearing more of your thoughts on this subject. 
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310014
05/07/09 11:35 AM
05/07/09 11:35 AM
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Joined: Jan 2003
Posts: 1,996
s. e. pa.
calrobb2000
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,996
s. e. pa.
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hi what cfm carbs are you running ? prob fuel dropping out of suspension due to low speed volicity ? smaller carbs or smaller plenum may be in order for lower speed operation , may have to giv up something to get better operation ? 
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310015
05/07/09 11:37 AM
05/07/09 11:37 AM
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Joined: Oct 2007
Posts: 4,206
New York
polyspheric
master
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master
Joined: Oct 2007
Posts: 4,206
New York
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If that surge is 1 or 2 cylinders lean (which won't show on your sensors) vacuum advance will help.
Boffin Emeritus
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: polyspheric]
#310016
05/07/09 11:59 AM
05/07/09 11:59 AM
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Joined: Jan 2003
Posts: 4,573
...gently down the stream
LAR_414
OP
master
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OP
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Joined: Jan 2003
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I;m running a couple 650 double pumpers. I know that sounds like overkill, but it works quite well.
At this super low RMP that I'm having the issue, the throttle blades are barely halfway into the transfer slot. The air fuel mix is coming totally off the idle circuit at this point. I don't think that the cfm of the carbs is going to change this one bit. These carbs have screw in ifr's and I've played with them as well as the iab's and along with the 4 corner idle screws, it's pretty good.
Even with the A/F LM-1 meeter hooked up, there doesn't appear to be any lean spikes at all. Granted, I can't be 100% for sure, but of the 4 cyl at a time that I can read, the readings are rock steady. And I've seen them fluctuate a bunch of times per second, when there is a lean condition or spark issue. But I can't be 100% correct here.
I'm interested in trying to advance the timing up and try it out again.
I'd like to hear the theory on the reason why the timing would effect a large plenum setup.
I'm sure I'll have to give up something to get some more driveablilty here.
But belive me people, this isn't a huge issue at all. Most people could just live with it no problem, but I'd like to give it a shot and try and tune this out of my combo.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: polyspheric]
#310017
05/07/09 12:06 PM
05/07/09 12:06 PM
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Joined: Dec 2005
Posts: 1,495
Shelby mi.
JAKE68
pro stock
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pro stock
Joined: Dec 2005
Posts: 1,495
Shelby mi.
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I have worked with this problem on milder motors for a couple of years now. It is because what above had said aboit low flow and alot of volume. I have done alot to calm it down but it cannot be eliminated. Smaller carb or less plenum would work. I have tried to run them ritcher and leaner nothing worked. I can calm it down alot with fixed timing,higher idle,lean idle mixture,cracked open secondaries. This problem is kind of a given when using this intake and not being full race type apllication. I have seen some of my customers try high dollar aftermarket carbs from Bigs,Quick fuel, ect and not have any succsess. Jake
JAKES AUTOMOTIVE
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: Jimi_Vignogna]
#310019
05/07/09 12:18 PM
05/07/09 12:18 PM
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Joined: Dec 2005
Posts: 1,495
Shelby mi.
JAKE68
pro stock
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pro stock
Joined: Dec 2005
Posts: 1,495
Shelby mi.
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Quote:
well you got that covered, do not use vacumm advance,i would keep the timing the way you have it, under the carbs are the carbs just open to the plenum or do you have a 4 hole spacer of some sort, i have one of these intakes here that is going on a 377 with center squrters, this intake is open under neath the carbs, i am planning a pair of hvh super suckers for under the carbs.
Jimi you may be on to something with the four hole spacer as upposed to the open. It may change the signal to the carbs and stable the idle. I have a customer that I can call and have him bring the car back to try that. Put it back on the dyno and see if that looks clean or not. Jake
Last edited by JAKE68; 05/07/09 12:20 PM.
JAKES AUTOMOTIVE
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: JAKE68]
#310020
05/07/09 12:44 PM
05/07/09 12:44 PM
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Joined: Jan 2003
Posts: 4,573
...gently down the stream
LAR_414
OP
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OP
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Joined: Jan 2003
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I don't run any spacer at all. I figured that I had enough Plenum volume! Maybe I'll try running a couple 1/2" thick 4 hole ones under each carb. Directly under the carb is just a big valley. I was thinking of making some sort of spacer shaped like a dome to help suspension or puddling. I can also reduce the plenum volume in numerous ways between the two carbs area. Any other ideas?
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310021
05/07/09 01:36 PM
05/07/09 01:36 PM
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Joined: Mar 2005
Posts: 2,172
Ohio
theclutcher
top fuel
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top fuel
Joined: Mar 2005
Posts: 2,172
Ohio
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install a plate between front and rear halves of intake.
Run front 4 cyls on one carb rear on other.
Remove material from divider wall as you see fit for your desires.
Did similar on team g with dominator plenum, basically make it a dual plane.
Last edited by theclutcher; 05/07/09 01:39 PM.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: patrick]
#310024
05/07/09 02:02 PM
05/07/09 02:02 PM
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Joined: Jan 2003
Posts: 75,004
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,004
U.S.S.A.
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Quote:
expensive solution: multipoint EFI with twin TB's and the fuel rails/injectors internal to the cross ram. gets rid of a lot of wet-flow fuel distribution problems 
there was a setup in a mag recently like that , multi point FI on a croaaram hemi , injectors and plumbing in the intake , to air horn throttle bodies on the top.
Larry , you have 1300 cfm on a 408ish inch engine ? I would think a smaller pair of carbs as a test would be the first test ?
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: JohnRR]
#310025
05/07/09 02:16 PM
05/07/09 02:16 PM
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Joined: Aug 2003
Posts: 11,179
Atco NJ
DJVCuda
I Live Here
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I Live Here
Joined: Aug 2003
Posts: 11,179
Atco NJ
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Quote:
Quote:
expensive solution: multipoint EFI with twin TB's and the fuel rails/injectors internal to the cross ram. gets rid of a lot of wet-flow fuel distribution problems
there was a setup in a mag recently like that , multi point FI on a croaaram hemi , injectors and plumbing in the intake , to air horn throttle bodies on the top.
Larry , you have 1300 cfm on a 408ish inch engine ? I would think a smaller pair of carbs as a test would be the first test ?
I have a combined 780 cfm on my 360 and can idle at 700 rpm in drive - ( 2 holley 390's) but the tunnel ram dont have all those turns like a cross ram does, so fuel suspension is less of a problem for me
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: DJVCuda]
#310026
05/07/09 02:21 PM
05/07/09 02:21 PM
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Joined: Jan 2003
Posts: 75,004
U.S.S.A.
JohnRR
I Win
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I Win
Joined: Jan 2003
Posts: 75,004
U.S.S.A.
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Quote:
Quote:
Quote:
expensive solution: multipoint EFI with twin TB's and the fuel rails/injectors internal to the cross ram. gets rid of a lot of wet-flow fuel distribution problems
there was a setup in a mag recently like that , multi point FI on a croaaram hemi , injectors and plumbing in the intake , to air horn throttle bodies on the top.
Larry , you have 1300 cfm on a 408ish inch engine ? I would think a smaller pair of carbs as a test would be the first test ?
I have a combined 780 cfm on my 360 and can idle at 700 rpm in drive - ( 2 holley 390's) but the tunnel ram dont have all those turns like a cross ram does, so fuel suspension is less of a problem for me
Dave 780 on the tunnel ram is like having a thermobog on a dual plane on your 360.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: JohnRR]
#310028
05/07/09 02:29 PM
05/07/09 02:29 PM
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Joined: Aug 2003
Posts: 11,179
Atco NJ
DJVCuda
I Live Here
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I Live Here
Joined: Aug 2003
Posts: 11,179
Atco NJ
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Quote:
Quote:
Quote:
Quote:
expensive solution: multipoint EFI with twin TB's and the fuel rails/injectors internal to the cross ram. gets rid of a lot of wet-flow fuel distribution problems
there was a setup in a mag recently like that , multi point FI on a croaaram hemi , injectors and plumbing in the intake , to air horn throttle bodies on the top.
Larry , you have 1300 cfm on a 408ish inch engine ? I would think a smaller pair of carbs as a test would be the first test ?
I have a combined 780 cfm on my 360 and can idle at 700 rpm in drive - ( 2 holley 390's) but the tunnel ram dont have all those turns like a cross ram does, so fuel suspension is less of a problem for me
Dave 780 on the tunnel ram is like having a thermobog on a dual plane on your 360.
yup - only faster!
12.56 @ 106 compares to a stock ported iron intake and 780 cfm holley at 13.2 @102
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310030
05/07/09 02:49 PM
05/07/09 02:49 PM
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Joined: Jan 2003
Posts: 4,573
...gently down the stream
LAR_414
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OP
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Wow that's some sweet work there on the EFI. That is sure nice. I'm sure it would be a challenge to get it inside this intake. Here's a pic, during mockup, before any damn's and such.
On the carbs, No sense trying smaller ones. It's not overcarbed. Even though theres not sure fire way to pick CFM for an engine, I'm in the ball park.
Remember, the carbs are rated at 1.5inches of vacuum. At WOT, you better not be pulling that kind of vacuum, or you have a major restriction. Assume your pulling 3/4 of an inch. A (rated 650 carb at 1.5 inches of vacuum), probably flows more like 450 cfm at 3/4 inch draw. Two of those is about 900cfm. My engine at 414 cubes and 6500rpm should need about 800 cfm at 100%VE. I'm Good!
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310032
05/07/09 05:15 PM
05/07/09 05:15 PM
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Joined: Jan 2003
Posts: 1,938
Sonora CA
Mopar_Rich
top fuel
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top fuel
Joined: Jan 2003
Posts: 1,938
Sonora CA
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Quote:
Here's a pic, during mockup, before any damn's and such.
I never tried one of those manifolds. The issue would be the vertical distance from the runners to the cover.
The biggest problem with the EFI conversion is the cost. Not only are the manifolds expensive but you have to commit to the entire EFI process. NOT for the weak of heart.
I don't have much input to your basic problem with the carbs. Sorry.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310033
05/07/09 08:23 PM
05/07/09 08:23 PM
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Joined: Oct 2005
Posts: 4,945
WI
Dcuda69
master
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master
Joined: Oct 2005
Posts: 4,945
WI
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Quote:
Wow that's some sweet work there on the EFI. That is sure nice. I'm sure it would be a challenge to get it inside this intake. Here's a pic, during mockup, before any damn's and such.
On the carbs, No sense trying smaller ones. It's not overcarbed. Even though theres not sure fire way to pick CFM for an engine, I'm in the ball park.
Remember, the carbs are rated at 1.5inches of vacuum. At WOT, you better not be pulling that kind of vacuum, or you have a major restriction. Assume your pulling 3/4 of an inch. A (rated 650 carb at 1.5 inches of vacuum), probably flows more like 450 cfm at 3/4 inch draw. Two of those is about 900cfm. My engine at 414 cubes and 6500rpm should need about 800 cfm at 100%VE. I'm Good!
Maybe a spread bore type carbs? I know it would be work to fit them on that intake(spacer/adapter?)Smaller primarys(better signal/velocity)but still the CFM you need at WOT.Just a thought? I've been watching this thread as I have the same problem(as I said in your Q&A post),great reading BTW!!Please let us know what you find as I'm sure there are other members who have the same issues with low speed drivability. 
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: theclutcher]
#310034
05/07/09 08:45 PM
05/07/09 08:45 PM
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Joined: Apr 2003
Posts: 1,832
Fort Morgan
1OFNONE
Has been a member for quite a few years, so relax.
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Has been a member for quite a few years, so relax.
Joined: Apr 2003
Posts: 1,832
Fort Morgan
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I spoke with Damon at Diamondback Engines in Texas who is the current foremost authority on these intakes. He told me to put a 1" 4 hole spacer under each carb. That made a huge difference.
Next he said to put a 1/4 " spacer between the lid and the bottom to increase the radious the fuel has to turn in due to it just slams into the bottom of the plenium. I never did that cause the spacers cured my drivablity issues.
Call him and pick his brain. Very smart man.
Thats my 10 cents.
So the bartender says to the horse " Gee, Why the long face?"
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310037
05/08/09 09:49 AM
05/08/09 09:49 AM
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Joined: Mar 2005
Posts: 2,172
Ohio
theclutcher
top fuel
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top fuel
Joined: Mar 2005
Posts: 2,172
Ohio
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The way this intake is designed, I'd have to separate the right and left cylinders, not the front and back ones.
Thats what I'd do, then adjust hgt. as needed,
could almost do that on car.
After trying the 4 hole spacers...
Last edited by theclutcher; 05/08/09 10:31 AM.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: theclutcher]
#310038
05/08/09 10:24 AM
05/08/09 10:24 AM
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Joined: Dec 2005
Posts: 1,495
Shelby mi.
JAKE68
pro stock
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pro stock
Joined: Dec 2005
Posts: 1,495
Shelby mi.
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This morning I did a dyno tune on a 68 hemi dart with the mopar cross ram. It was weird that this thing did not have the typical surging idle. When I went to pull the carbs to do some jetting bingo there was a 4 hole spacer. Maybe we are on to somthing. Jake
JAKES AUTOMOTIVE
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: GomangoCuda]
#310042
05/08/09 02:15 PM
05/08/09 02:15 PM
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Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
BradH
Taking time off to work on my car
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Taking time off to work on my car
Joined: Jan 2003
Posts: 15,439
Val-haul-ass... eventually
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Quote:
Quote:
I have an intake that almost nobody has messed with.....and I like it that way
I understand the "being different" aspect. But there comes a point where the PITA factor associated w/ taking that approach comes back to haunt you... especially when you're trying to sort out a combination that was never intended to work well under those conditions.
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: GomangoCuda]
#310043
05/08/09 02:18 PM
05/08/09 02:18 PM
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Joined: Jan 2003
Posts: 4,573
...gently down the stream
LAR_414
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OP
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Joined: Jan 2003
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If I was interested in going fast all the time, I'd put something else on. My car isn't a race car. I feel that I've already proven that the STR-12 isn't junk. I'm getting 3mpg better gas milege with this vs my Home ported M1 single plane with home built 900+cfm carb. That old combo had no issues and was tuned very very well, both at the track and on the street. This intake setup was worth 3mpg / 2mph and about .2 et over the old combo. This is in the same car, same track, same conditions. I'll stick with it for now
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310046
05/08/09 03:31 PM
05/08/09 03:31 PM
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Joined: Apr 2007
Posts: 871
WA 98043
thecarfarmer
super stock
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super stock
Joined: Apr 2007
Posts: 871
WA 98043
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Quote:
If I was interested in going fast all the time, I'd put something else on. My car isn't a race car.
I feel that I've already proven that the STR-12 isn't junk. I'm getting 3mpg better gas milege with this vs my Home ported M1 single plane with home built 900+cfm carb. That old combo had no issues and was tuned very very well, both at the track and on the street.
This intake setup was worth 3mpg / 2mph and about .2 et over the old combo.
This is in the same car, same track, same conditions.
I'll stick with it for now
"11.07 and 120.4 mph
15.5 mpg(highway) pump gas small block, Cross Ram."
Kinda' speaks for itself.
Keep marchin' to the beat of a different drummer - it seems to be workin' for ya'!
I think you're onto a good idea in checking what more/less timing does; cheap and easily undone.
What about messing w/ air bleeds? I've found a number of cars I've worked on went a little lean off-idle, right where they'd spend a good portion of time cruising. Just a thought...
-Bill
Seduce the attractive, and charm the rest.
******
489 C.I.D., roller cam, aftermarket heads, tunnel ram, stock '54 Dodge rear axle assembly: which of these doesn't belong?
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Re: Cross Ram - inside work - dividers / block offs.....
[Re: LAR_414]
#310050
07/10/09 12:49 PM
07/10/09 12:49 PM
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Joined: Jan 2003
Posts: 4,573
...gently down the stream
LAR_414
OP
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OP
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Update,
Made large sheet metal dome under each carb to direct the fuel and reduce volume. Pretty sweet job, if I don't say so myself. Took a great deal of volume out of the intake, and keeps the fuel from puddling directly under the carb in a large dead area.
No change! Still bucks and kicks as it always has.
SO I've done the following and noticed no change:
-Played and played and played with carbs, with A/F monitor hooked up. Went Rich / Lean and everyhwere inbetween. IFR changed, IAB changed, Open rear blades more than front, vice versa,.....
-Timing all over the place from locked out low / normal / high. Curve from BTDC to very little...all maxed out to the same 35 degrees or so.
-Changed the intake shape a bit to aid distribution and signal to carb, taking volume out
-Added 4 hole spacers 1" thick
-Increased valve lash about .006"
Nothing has changed the problem yet.
Cam too big? 260 @ .050 on 110LSA installed at 106 Solid fast ramp.
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