Tunnelram woes.....

[BattlestarGalactic]

Ok.  Got it in the car all is well.  Sorta.

I can not get the car to launch, at all.  Dump the clutch and it near stalls the motor.  Data logger says it gets to 2000 rpm as it kinda recovers and goes.

I don't use a 2 step.  I hold the rpm at around 4500 rpm, dump the clutch and go WOT.  Been this way for 26 yrs.  Suddenly it seems the intake does not like that.  I still run my 1850 holleys like I have for 26 yrs.  I originally had them sideways on the tunnel ram to allow changing up to double pumpers at some time.  I turned them straight and the aame issue.

I have a pr of 660s that will find their way on for my next try.  Friend says he sees no black smoke so it appears it is not too fat.  We dynoed the 660s on one pull but they didn't work much better over the 1850s so I kept with my old 1850s.  Though the dyno does not replicate real work driving so I think it needs more pump shot.  I wonder if upping the squirters on my 1850s might help.  I think it has #35 in them now and 50cc pumps as they have been forever.

Any rhoughts?

[1968galaxie]

The tunnel ram will likely want more pump shot due to the large plenum.
What pump cams do you have? There are different cams that work with the 50cc acc pumps.
Try adjusting or changing pump cams, and then try the larger shooter.
I am sure you will find what the TR likes!

Cheers

[BattlestarGalactic]

Oops, just confirmed what is in there.  One #37 and a#28!  Yikes, no wonder it falls on its face.  How the heck did I get this so messed up??  Been so long since I even looked at the squirters in the wagon carbs I was completely off base.

The cams are in the #2 slot, so it has a long gradual pump, not a big short burst.  With launching at 4500 the throttle is open a bit and I want some pump left.

[jayb]

+1 on the pump shot, Larry.  You need a BIG pump shot with the large plenum of the tunnel ram.  Pretty sure that will solve your problem.

[BattlestarGalactic]

I found a pair of 25's and drilled them to .040 and will see if that helps.  Going to take my pin drills and play with it the next time out.  Maybe I will get a chance before next Sundays stick race.

Sadly TnT nights haven't been available lately due to weather.  I had to test today with local points race...and only one TT.  Ugh, can't do much playing around with that.  Not paying to buy back just to get another pass.

[jayb]

I know of some tunnel ram guys who have gone to 2 50cc REO pumps on the carbs to get enough pump shot.  That's one thing the 660s are good for.  If you have a set of those, I would give them a try...

[TomP]

Just my opinion and nobody listens to me... too much plenum...plenum is NOT your friend.  After seeing a friend's intake which looks like tha box a pair of Magic Johnson's shoes came in with 2" long runners to the head fall on it's face on the car as if it was a 10,000 lb car with a close ratio and 2.75 gears.... I made my intake look like what your tunnel ram would be if you unbolt the top section and bolted the carbs to the base on 1" adapters.
 It will still launch at 2000rpm and pull hard. It has less than half the plenum area of a Tunnel Wedge. While it may not be the ideal design it has less adverse affect.

[BattlestarGalactic]

Tom, advice well taken.  The plenum on this Weiand is not that big actually.  Slightly larger then the TW.  The scary thing is the fact I had two different squirters on the carbs, and one being almost stock size and it worked perfectly all these years on the TW.  I can see why it doesn't work now, and I should have looked at them sooner. 

Jay, I do still have the 660s and will try them if need be.

Here's a story for you.  The 660s on the blower car?  It has a huge bog at lower rpm.  I drilled the squirters out to the largest drill I had and it still doesn't like it.  I need to being running 3000 rpm or so before flogging it or it drops on its nose.  Unless I slide the clutch and get the tires spinning.  Im not sure the 660s will do any better on the tunnel ram?  Granted the plenum is no where as large as that 671 blower.  I wonder if I won't need a pair of 650-750 DP to get enough shot to overcome.

Dyno and real driveability are two different ballgames.

[fekbmax]

http://garage.grumpysperformance.com/index.php?threads/tuning-a-tunnel-ram-intake.5175/

Larry, you may have seen this before,  I possibly posted it several years ago ,I cant remember . It's a long read but there's tons of great info in this . You may want to check it out if you haven't seen it yet. It's an older read but I swear I learn (or remember) something every time I read it. 

[cammerfe]

I wonder if 'Grumpyvette' ever learned to spell straight?

(Massive amounts of good hard technical info however.

KS

[BattlestarGalactic]

Well, we're in good shape presently.

Spent last Fri at TnT and drilled the squirters to .045 and to .055 and saw improvements.  Then at the first stick race on Sunday I drilled them to .065 along with installing drilled screws(that I was told I needed for anything over .040 holes).  I've got a pretty good hold on it for now.  So much I actually made it to the semifinals!  Not bad.

I need to replace leaky squirter diaphrams and will install jet extensions on the secondary sides.  It have jet plates already installed so it's an easy thing.  I also have proper floats on the front side so just need to swap ends.

I'm sure I will upgrade carbs at some point but for now if I can make the season on these I'll be happy.

Thanks all.