Throttle stop using 2 carbs
 

We just added a 3rd car (Undercover dragster) to our team and will be installing a 630ci Mopar Indy motor.

The motor has 2 Demon carburetors and we want try and run it in S/C this way.

Does anyone have any advice for throttle stopping a car with 2 carbs?

Any advice would be helpful.

Thanks,
Brad Rose
Rose Racing Team

Re: Throttle stop using 2 carbs
 

I don't think the car will know or care how many carbs it has on it.
You will still need to get the on the stop RPM down in the 4000-5000 range and you may need a little larger throttle stop cylinder (both bore and stroke) to acomplsh this and overcome the extra effort needed to open both of them up.
But with the motor breathing through eight venturi instead of the typical four it may be a little less affected by changes in the weather but that's a good thing!:D

Just my 2 cents worth!

Re: Throttle stop using 2 carbs
 

Thanks Bill. I've heard that turning the CO2 regulator to somehwere between 100 - 125 lbs. would help as well.

I appreciate your help.

Brad

Re: Throttle stop using 2 carbs
 

Reagan Wilson runs two carbs on his 632 powered Super Street truck and has pretty good success. I think he runs two under the carb stops but am unsure of the linkage. He often visits this site so hopefully he will enlighten us more on the subject.

Re: Throttle stop using 2 carbs
 

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But with the motor breathing through eight venturi instead of the typical four it may be a little less affected by changes in the weather but that's a good thing!:D

Just my 2 cents worth![/QUOTE] A fact that many overlook when telling you all the reasons you should not run a tunnel ram. ! .....I ran one for years on my AMC'S and on my small BBC'S with great results. .....I used the Bill Mitchell 1" bore cylinder @125# ,with the Enderlie linkage. ....I had to fab a longer arm on the bell crank to get a lever ratio that worked ,but that was about it. .....I have a friend who has a TS car he occasionally runs in SG with the same setup on a 638 ; to run 9.90 @ 178 mph in a 2600# car,so your setup should work. .......Good luck ......Tom

Re: Throttle stop using 2 carbs
 

I'm really interested to see how the two under carb stops work. Dedenbear and Biondo have both recommended in linkage stops, but I like the under carb stops better.

I guess the whole thing comes down to consistency. If an in-linkage stop is just as consistent as under carb stops - then I guess I'd like saving the money.

Brad

Re: Throttle stop using 2 carbs
 

under card stops.......... that would be interesting..........you would almost have to tie them together, and just use one actuator , other wise setting the drop would be a real pain. I would think anyway.


just my 2

Rick

Re: Throttle stop using 2 carbs
 

Well if you use under the carb stops, you will not get the accelerator pump shot when the stops open which if you don't open the stops slowly enough. could cause the motor to stumble or bog Besides I'm a big fan of K.I.S.S.
Make darn sure that if you use a pneumatic cylinder in the linkage that you have a positive (solid) stop under the pedal or it won't repeat and will drive you nuts, but you probably knew that already.:)

Re: Throttle stop using 2 carbs
 

Mark Cooke from Badman Racing engines does it, so does Josh, Josh is #1 in D3 S/C right now. 2 dominators, under carb stops I beleive.

Re: Throttle stop using 2 carbs
 

Another concern I have is if the under carb stops will "puddle up" and "bog" when they come off the stop.

It's glad to hear someone doing well with a dual carb setup in S/C D3. I was just doubting this setup because I haven't heard of anyone doing well with a dual carb setup and throttle stop, until now. I thought Ray Connolly used to use a dual carb setup on his dragster?

Maybe we'll try it in S/C for a year and then move to Top Dragster if it doesn't work out. My brother will be driving this setup and he's never driven anything down a dragstrip before. This is why we want him to run in S/C. That way he has a second or two to think about things. He is going to Frank Hawley's school in February, so that should help. I guess because we MIGHT move him to Top Drgaster later, maybe we'll just go with the in-linkage stop. Who knows. He's not racing until next year and I've changed my mind 3 times this week about which throttle stop to use. It ought to be an interesting fall/winter.

Thanks for all the advice.

Brad

Re: Throttle stop using 2 carbs
 

Call Gary at #1 stop he can set you up. Parts and info.

Re: Throttle stop using 2 carbs
 

It's been a few years since I ran a tunnel ram in SC, but I know that it will work well if you're willing to test. I tried butterflies, discs, and in-line. Once I got used to the in-line I liked it the best. With today's butterflies you would probably be fine, I just wouldn't want all the junk under the carb on a big HP motor if SC wasn't my ultimate goal. I would suggest an in-line, then use it as an enhancer when you bracket race or TD race.

Just my .02 cents...good luck! A barrell over every cylinder is a very good thing.

Re: Throttle stop using 2 carbs
 

Thanks Mr. Schmidt - that's what I was looking for.

I looked around a little bit at the Cordova divisional and only seen two racers using a 2 carb setup in all of S/Comp. My dad also spoke with Ray Connolly because he used to run 2 carbs on his dragster but now only runs one. He simply said it was much easier with just one. Obviously we agree, that's why everyone is doing it with just one carb.

The other issues we are having is:
1. Who makes the scoop mounting tray for dual carbs?
2. Not a lot of choices on where to get headers made for a big block mopar. We have a set of (basically) brand-new Dynatech headers for sale for a big block Chevy. They came with the car and we thought we would just cut them up, BUT they are way too nice for that. They are (downswept) step headers that are polished and plated with typical collectors. No discoloration or scratches.
3. No mid-plate for big-block mopar and Undercover chassis.
4. Who sells a dragster lift for enclosed trailers? We just need the kind that lifts the front end.

I have a friend that owns his own fabrication company and he's willing to make a lot of these things for me, but he's got a lot of work and I hate adding to his plate.

I thought it would be relatively easy buying a dragster and just getting stuff to bolt together. I thought wrong.

Thanks for all the help and advice.

Brad

Re: Throttle stop using 2 carbs
 

"Mr Schmidt" Oh crap we will hear this forever..........and ever!!!!!!!!

Brad for the lift, most of the ones I have seen are just built by the owners. Mark had one in one of his trailers and they are fairly simple.

Headers might be hard to find unless you have a set built. There are a handful of diggers with those motors.
If there is anyway to stay with one carb Ray is right. Unless you have a monster motor one is better.

Re: Throttle stop using 2 carbs
 

A 1" bore pneumatic linkage stop from Bill Mitchell / Hardcore should do the trick for you. As far as finding a source for BB Mopar dragster headers, Hedman has them available as well as Schoenfeld. Tom Goldman knows of what he speaks, he got me into the Winner's Circle a few years back with my "8-barrelled" AMC in S/C.
Good luck w/ your project.
-Don

Re: Throttle stop using 2 carbs
 

The first year they ran Super Comp at Indy I left the IHRA Top Dragster engine combo in the car. Gary Heuer (#1 Stop Products) is a good friend of mine and lives here in town. He did up a top plate for the tunnel ram that used multiple air cylinders and coupling joints to run stops under both carbs. Even back then in '92 (?) it went 8.90 at almost 175. Steve Dallas (from Houston, lol) did the big mph deal too back then but with a single carb. Gary's number is 319-277-5290. Tell him I sent you; he's a walking encyclopedia of tech information when it comes to stops and timers. As a footnote... his first stop was built at my request for my S/ST car back then when I saw the Dedenbear stop and how much they cost for what you got. Gary was very integral of my racing program in Super Street and then Super Comp. A great guy.

Steve Oldani

Re: Throttle stop using 2 carbs
 

Thanks Steve. We'll give him a call.

We bought a set of headers. $1500 later and it's not so much cheaper running a dragster versus a door car.

I know why everyone runs a BB Chevy, but these Mopar parts aren't getting any cheaper.

Brad