Finetuning questions - do I need a high-stall torque converter ?

Hi everyone!

I don´t know how to continue at the moment.
I am generally happy with my setup - but the car could launch better and I´m not able to do a burnout. The engine just goes up to 2200rpm (converter stall speed) but seems not to have enough torque to spin the tires. Either the carb is not yet set up properly, or I need a torque converter with higher stall ? Has anybody same experience with the cam I use ?
Have tuned the carb in with an AFR meter - could not identify lean or too rich spots.

Here are the specs of the components I used:

67 Dodge Dart
318 bored to 323
273 forged crank & rods - pistons weight matched to have a balanced set-up.
Hughes HUG HEH1928AL cam
Intake Lift .489"
Intake Duration at .050" 219°
Lobe Separation Angle 111º
Intake Centerline 108º

Edelbrock Thunder 500 AVS
/6 torque converter - stalls at around 2200 when I hit the brake and full throttle.
Heads are cast iron standard heads, ported as far as possible
TTI Headers 1-5/8" O.D. primary tubes steps up to 1-3/4" secondary tubes with 3" 3-bolt collectors

310hp on the chassis dyno
3.23 sure grip 8.75
225/70R14
beefed 904

ran a 14.1 on my first quarter mile run, letting the trans shift

Should I go for a new torque converter with 2500 stall ? I read that the efficiency of a custom made converter will be better than my /6 converter. Or is this money spent needlessly ?

I´m fancy with this one: http://www.edgeracingconverters.com...4-transmissions-p-16.html?number_of_uploads=0

Appreciate your thoughts!
Lars

ive had same issue with 284/484 in 318 demon with hughes 3000, goes up to 2900 and takes off pretty good, no tire spin, if i adjust back brakes off a bit it starts frying the tires around 2200 rpm. thats my experience with too much cam,but it sure starts to pull around 3500

What were your 60' times and 1/4 mph? At what rpm was it shifting? Definitely looks like your loosing ET somewhere.

Hi lars, to me it seems that you need at least 4000 rpm stall.....;-)

but the engine should be able to spin the wheels......does the carb open up fully? Where is your ignition timing initial and all in?

btw.....i like your dart!

michael

You should be able to roast the tires as is.

In regards to the TC, it's best to have one spec'd for your combo and intended usage. Picking a stall number out of the air isn't going to help.

You MUST be 100% up front with whomever builds your converter in order for it to perform like it should.

This would be a better choice and shoot for around 3200 stall:

http://www.edgeracingconverters.com/904-c-7_8/street-edge-converter-for-chrysler-904-transmissions-p-15.html

Give Andre at Edge Racing a call. He loves to talk Mopars and I am sure he would have a recommendation for you.

What's the timing profile. Initial, total and all in point?

Cam installed where? If you say dot to dot you don't know where it's installed.

what's your compression ratio, were heads milled ,flat top pistons?

What elevation are you at?
What is your exact compression ratio?
At what rpms were your peak torque and hp numbers recorded?
Is your carb getting fresh cold air?
Are you running an exhaust crossover?

That combo, with those tires, at sealevel, and fresh air, should be a tire fryer, just as it is. The AVS, having an AirValveSecondary, depending on the spring tension, the compression ratio,and your elevation, could be/probably is, the issue.
The 3.23s and 2200 TC aren't helping your ET, but at 14.1 seconds, that should put you at just over 100mph, which is pretty fine for your combo!
If it was mine, I'd be opening the secondaries earlier, or throwing a DP carb on it. Then maybe a lil more gear,and last on my list would be a higher stall TC. Then again, in a country with a no-speed-limit hiway, maybe the TC could be second, and the gears last.
Save your brakes,install a line-loc.

You using the 318 heads?

Great - thanks for the quick and many replies!

Here some additional info:

Heads are from a 1970 318 - compression 10:1
Fully ported with 1.88" Inlet valves and 1.5" Exhaust valves.
Pistons are flat top.

Cam is calibrated corresponding to the ISL from Hughes.

Ignition is 12° before dead center at Idle
and 36° before dead center all in.

Exhaust is without crossover.

Elevation is at sea level.
I have no scoop - so it does not always get perfect cold air, specially in the city after lot of idling.

Max. hp recorded at around 5200rpm - Torque was not measured.

Will check at next opportunity if valve secondary fully opens when I try to do a burnout.

Quarter mile details:
---------------------------
60ft 2.247sec
330ft 6.029 sec
1/8 mile 9.141sec
1/8 mile speed 79.6 mph
1000ft 11.814 sec
1/4 mile time 14.109 sec
1/4 mile speed 97,9 mph

Shifted with automatic - shift point around 5000rpm


Second pass, manually shifted around 5500, had quite a lot of wheel spin at launch.....
------------------------------------------------

60ft 2.380 sec
330ft 6.205 sec
1/8 mile 9.307 sec
1/8 mile speed 79.75 mph
1000ft 11.95 sec
1/4 mile time 14.203 sec
1/4 mile speed 100.1 mph

Heehee
Your torque was so measured; it's just buried in the Hp graph. With a little ingenuity it can be extracted. Dynos dont measure horsepower....they measure torque over time, heehee. I would extract it, to see just what is going on, down low.
Well, at sealevel and a TRUE 10/1, you're in pretty good shape.That cam at your installed centerline, makes a Dcr of about 8.15; which with iron open chamber heads, is just about perfect.Your timing is also pretty darn close.The Hughes fast-rates are sweet.
I do see a TC in your future.
But before that day comes, I would borrow a carb and maybe a rearend.The carb would be with slightly bigger primaries, like a 650DP, and the gears would be 3.55s.The DP, if you can tune it to not bog initially, will really launch it! The gears,won't get you off the line any quicker, but,at 10% more gear, the engine will motor away from the line quicker. But if you cannot borrow that stuff, then the TC will be the way to go. Call your favorite supplier, and follow his recomendations, or Perhaps someone more experienced than me will chime in.
And I would recommend, a part-throttle KickDown valve for around town, and for track duty;at least 4.11s to get your Rs up, through the traps. Those 4.11s will get you about 105mph at 5500rpm.(3400@65mph).If you've been thinking about gears and/or stalls, and you have a multi-purpose vehicle, choose carefully, as it's very easy to go from multi-purpose, to track-only.

Notice that the timeslips show a very significant improvement to the MPH with the addition of shift rpm. You can play with that some more, to find the perfect shift rpm.

One thing you can experiment with is initial timing. Buzz your engine up to the aforementioned stall speed of 2200( in N/P) and check the timing(Vcan defeated). Then add about 3 degrees, at that 2200. Drop it back to idle speed. Take it out for a spin. For this test;do not exceed about 3000 rpm at full throttle, or back-off if you hear detonation. This test is just to compare off-the-line improvement. If no improvement, put the timing back. But if a significant improvement is found, I would dial in 2 or 3 more and retest.On the street, the improvement may be hard to gauge, but the 60fts should pick it up quick. When it stops improving, Jackpot! Rev it up(N/P), and check the new maximum,total power-timing. You will have to mod the dizzy, to take out the difference in timing, from before to after.Then go drive it for a few hours, and have some fun.

You asked about experience with that cam. I have none. But I do with the next bigger one; the HE2430, but in a 360.It was an awesome tire fryer right off idle and with a 4 speed and 3.55s. I only changed it out when it dropped a couple of lobes, when they took the zinc out of our oils back in the early 2000s. I swapped in a HE3037 for a bit more topend. Turns out I liked the smaller cam better.At one time that HE2330 cam,cruised at 1500rpm,62 mph(100kph),with a double O/D, and returned 14.2Km/liter.(32mpgUSg)!At 2000rpm it cruised at about 85mph, and the mileage only dropped a little. That was sweet!
If you are considering a cam swap, bear in mind that your Dcr will fall some,unless you are able to keep the ICA where it currently is. If the Dcr falls, so will low-rpm performance. Then, for sure, you will need a TC and gears.To keep the ICA,with a bigger cam, you will need to tighten up the LSA.

next time you try to do a burnout, push the pedal to the metal ;-)

Michael

3.55 gears and some decent tires should get you into the low to mid 13 at least . Seems tire spin is hurting your 60 ft times . And you should try shifting @5800 ,but a bigger carb would be needed 650 at least . that 500 cfm is ut of steam early @5200 rpm max hp should be around 5600 to 5800 rpm .

with no speed limits get an overdrive if you change the gears , always fun to find the top end of a car . and a trans cooler if you get a high stall converter

First thing I would do is recurve the ignition. Get as much initial timing at idle as you can without the starter lugging after heat soak. That initial timing plus whatever # to get you to 34* total mechanical. Low end throttle response will improve with more initial timing.

After you recurve ignition the AFR will change since you are igniting the air fuel mix earlier. If your going drag racing I would run a 600-650 DP. You need the pump shot to get out of the hole. You can tune a DP to get fuel mileage if you put the effort into it. Once it's dialed in you won't want to keep your foot off the go peddle.

Get a set of MT ET Street drag radials for the track. They hook good at around 15-16 PSI with a short burnout to clean them up. Street tires don't cut it at the track.

I ran a /6 converter in my 904 low gear set, TF2 shift kit, 3.91 gear and it was fun with a stock Magnum 360. Ran high 13s with street tires and lots of wheel spin.

Installed a 234@50 cam, drag radials and a 3200 10" Turbo Action converter. Car runs 12.30 and I'm still tuning. I spoke with Paul Forte at Turbo Action after sending him all my combo info and took his recommendation.

The $600 for the converter was the best bang for the buck performance wise I've spent. Drive it easy and you would never know it was a performance item. Hit the pedal and you better be paying attention.

You need to optimize your motor first and then get a converter and rear gear setup for how you want to use the car.

Considering where you are and that you likely want to be able to cruise it on the autobahn I would leave the gears as they are.

A good torque converter is a viable option just make sure you use an external trans cooler.3000 rpm would suit you well maybe 3500 if it is efficient.

A 600/650 vacuum secondary carb would help the upper mid range through the top end noticeably.

Your step headers are a bit big for this engine but I wouldn't change them out unless you have some 1 5/8 long tubes lying around.

You mentioned a lot of wheelspin on your second pass.Seems there is no problem doing a burnout.

I would experiment with shift points from 5500-5800 rpm to find the best E.T.

Thank you very much for the detailed explanations, tips and experiences!!!

I will first start with the ignition next week and at next opportunity with a 650cfm carb.
I mainly drive the car in the city, sometimes on the autobahn and 2-3 times a year on the strip. I think I will pass on changing the gears - maybe I can borrow one for the strip to test.

One thing I really forgot - the times from the 1/4 mile passes were with a 7.25 with 2.94 & sure grip ;) I changed to a 8.75 with 3.23 some months ago but had no chance to test it on a track until now.....so maybe there´s an improvement timing wise already.

I have read a bit about carbs and most people say, for an automatic car and non-track-only I should go for a vac secondary not a double pumper - is that conform with your experiences ?

Will keep you updated ....

The converter is perhaps the most important part of an automatic equipped car. "Do I need a high stall" is not how you should look at it.

You should call a reputable converter company and tell them your entire combo as you've laid it out here to us. Let them help you choose one, or build one for your particular car. That is the best way.

Ideally you want your stall speed at within 500 RPM of where you make peak torque.

If you are questioning the carb tune, and the convertor stall I would have it chassis dyno'd and tuned.

But you said you had it dyno'd and had it AFR tuned. So the carb shouldn't be the issue at least not in regards to the tune.

Where did it make peak torque?

Seems like you have a relatively small cam. Fairly docile.

Carb is small and I'm not a huge fan of the eddy carbs in regards to performance. They are great for a guy who can't tune a carb and just wants a bolt on, turn key and go carb. A 600 hp style Holley would suit you much better IMO.

310hp doesn't tell me much. My car makes 2314 on a chassis dyno. It runs 11's in the quarter. Again, I'd like to know where it made peak torque. Doesn't matter how much it made.

You have no tire under the thing. It should boil then off the car. The gears aren't helping you though.

IMHO you'd be better off going to a higher stall speed custom convertor. It's going to be a better converter all around.

CallMeAl said:

Heads are from a 1970 318 - compression 10:1
Fully ported with 1.88" Inlet valves and 1.5" Exhaust valves.
Pistons are flat top.

Click to expand...

Is the compression ratio from an advertised value or computed form actual measurements?

Are the pistons at zero deck or below deck? If below deck, how much?

AJ/FormS said:

That combo, with those tires, at sealevel, and fresh air, should be a tire fryer, just as it is. The AVS, having an AirValveSecondary, depending on the spring tension, the compression ratio,and your elevation, could be/probably is, the issue.

Click to expand...

^^^
This,
At 100% V/E (volumetric efficency) --- @ 5.2k rpm = 485 SCFM, already on the
ragged edge of being 'choked'
Factor in BSFC ( brake specific fuel consumption) & My Ol Tired brain comes up with
an multiplier of 1.2 = 582 scfm...
Apologies Honored posters, got off on a tangent,
Back on topic...
Needs more Carb !!!!

roccodart440 said:

Ideally you want your stall speed at within 500 RPM of where you make peak torque.

Click to expand...

I think this needs to be considered with care..... I think this idea is for a car that is optimiozed for best ET's. It is not what you would necessarily do for a street car.

^^, That's right. I don't slip my clutch out to 4000 at every stoplight! or 3000 or even 2000. No. Generally,I blip the throttle and dump it. So it takes off at what? 1200ish(Ima guessing). with a starter gear of 3.09 x 3.55 = 10.97, and a sharp 360, I am gone. So that seems to indicate that if I was running an auto, then a 2200 TC would be plenty for something lie 90%, or more, of my driving
With a teener automatic and that torque-making cam, a 10.97 starter gear would translate to 3.73/3.55s. But the 2200 stall, could easily compensate for another ratio, so that could be downsized to 3.55/3.23. To my way of thinking, the cost to benefit ratio of swapping out the 3.23s, or the TC, Is just not there yet.
Now as to the carb.
mech1nxh did the math for us, and found a 580 to be nearly optimum. But you have to bear in mind that this is about the maximum requirement. If you redo the math for 2200, you don't need much of a carb to get off the line.And this is where the OP says he's having an issue. Otherwise he says he's generally happy.
If we re-read the thread, we find that OP mislead us. In the beginning he tells us that he's running 3.23s. But much later in post #17, he tells us that he was actually running 2.94s at the time of his having troubles, and has since then swapped in the 3.23s, and appears to not brought us up to speed on how it is performing with those.
Taking all that into consideration, we just need to get off the line a lil more briskly.
So what's that gonna take? Torque. We just need a few more ftlbs. OR, free up a few more Ftlbs.To that end, in post#9, I said install a line-loc. If your teener is not fighting the brakes, it will have more ftlbs left over for tire frying, and the TC will likely flash a lil higher. Then we could use a few more cfms to help make a few ft lbs more off the line. And a DP will cure the possibly resulting bog.
But more than anything, the little teener needs compression.Now he says it's making 10/1. But you know how that goes. We need cylinder pressure numbers. OP,You could have 10/1 and 120psi, and that teener will be lazy. Or you could have 10/1 and 185psi, and be SHARP.
And that takes us back to post #9, which I think, about covers it, except for timings which was covered elsewhere,and looks to be in the ballpark..
Now to the OP, There is a lot of very useful information for you in this thread, offered by a lot of gifted and talented people.I believe you can find success here, so all the best to you.

Timing isn't close at 12 initial.

good converters, at least now, aren't close to acting like a clutch.

War and peace is shorter than some of this stuff. ��

nm9stheham said:

I think this needs to be considered with care..... I think this idea is for a car that is optimiozed for best ET's. It is not what you would necessarily do for a street car.

Click to expand...

Right, It's a generalized statement. You have to take into consideration that it is a street car. My street car has a 3500 stall and that is where it makes peak torque as well. My dad's truck makes it well above that, in the 4's. Dynamic gave him a 3,000 stall. When he calls to get a convertor made they will ask him all the questions and set him up with what's best for him.

To the OP. A 3500-4000 stall converter, assuming it's a custom quality unit will drive like a regular car. It's not like dumping the clutch or feathering the clutch out at 4k RPM.