Jump to content
HybridZ

Tri-Power


Recommended Posts

Does anyone here know if the tri-power setup from Dick Goodmans car is emissions legal? Would it pass a sniffer test if it had too? I know the carb runs on two barrels during regular use and the other two kicks in on demand. The way they test it here in Texas is both idle then they rev it up to about 2,000 rpm. By the way who is a good source for this set up and how much?

 

On the emissions side of things, my Z is a 75 but there is something in the works about testing everything from 1968 till 2 yrs old. I might not even start the project if they even think of starting that again. Right now only the Dallas/Ft. Worth area is covered. The car is just tested on idle in park for part 1 then revved up to 2k i think for part 2. Then they do a visual (actually most of them pretend they know ) check the gas cap all the vacuum lines then the safety. They are also thinking about the remote sensing sniffers for people who live outside the DFW area. Usually a lot of people who fail the test here just buy a bottle of RXP. It reduces the emissions and negates the so called reformulated gas which actually burns dirtier and is now found in the water table. Actually the additive M.T.B.E. ( Methyl Tersiary Butyl Ether)the so called "cleaner gas" is the same stuff California is trying to flush out of their gas, is being pushed by the T.N.R.C.C. (Texas E.P.A) here believe it or not. Tanx for the replies.

 

[This message has been edited by Sumo (edited March 11, 2000).]

Link to comment
Share on other sites

Guest Anonymous

There is no way a tri-power setup would pass emmisions. All you have to do is look at the gas milage decrease when tri-power is used..most of it blows right out the exhaust pipe. The only reeason you would do this mod is because of nestalgic purposes...not becasue it is in any way practical.

 

SpencZ

Link to comment
Share on other sites

Emmission tests in Texas too? I guess its where we're all headed. If you know of a facility with a HC/CO tester that will let you use it, tune your car for test day. This involves leaning out the carbs to the max and optimizing your timing for a clean burn. Limp it to the test and then reset afterwards. Even @ 2000 w/o a load, as in a static test you should still be on the 2bbls. Are your tests made with the car in park/neutral, or on the rolling dyno type? In CO. They also have the idle and 2000rpm test. For older cars they give you a lot of room. Pre 74s are exempt from the visual part of the test, i.e. evap. emmiss., converters, smog pumps, etc. We also have "collector vechicle" tags, 25yrs older, good for 5 years. Some room to play before test day comes again. Many of my big cam buddies can't pass now so they are either race only or registered out of controlled areas(also coming to a close) I got around it with my cam's big lobe sep angle, 114 deg. Smooths out the idle, good for top end hp, and minimizes overlap, a big killer in emmiss.test. Supercharger really helps to clean up too. Some of your cam profiles would probably destroy the test equip! Just underway in our city is a "RD2000Van(?) that tests cars emmissions as you drive through their "emmission trap" and like photo radar, records your lic. #. Pretty rude! I got a notice in the mail after blowing through one. Still experimental, they invited me to a smog dyno test. I passed on the offer. Who else has emmission tests?

 

[This message has been edited by John Scott (edited March 11, 2000).]

Link to comment
Share on other sites

Hi Sumo, I think the best place to get a Tri-power setup these days is from Larry Fulton who's company is called "Automotion" (406) 453-5395. Sorry, he does not have a web site. Edelbrock still makes the manifold and you can pick them up on eBay quite often. BTW, over the years lots of GM cars came from the factory with Tri-power setups (the most popular being the Pontiac GTO) but not the small block Chevy!

 

Doing a Tri-power right is a bit of an art. The engine only runs on the center carb until you reach an certain throttle opening. I can adjust when the other two carbs to kick in from about 50% to 80% throttle opening. Each Rochester carb flows about 280 CFM so in total the whole system flows about 840 CFM. That's just a little bit more than the usual 780 CFM Holley that many people run.

 

The end carbs do not have idle or power circuits. The secret to getting the engine to idle right is preventing air from leaking around the throttle blades on those end two carbs. I have custom made throttle bodies, with double thickness throttle blades and a special throttle shaft to mount them in. The jets on the end two carbs are quite a bit bigger than the center carb because the power circuit in them is plugged.

 

Mine is part "Hot Rod Carburation" (who just went out of business) and part "Automotion". I've got it running but it's still in the garage thanks to Detroit's winter weather. We do have a guy in the club that has a Jamacian with a 383 SBC and the Automotion Tri-power setup and it is sweet. Larry Fulton even powder coated his carbs red to match is car and engine! Since you run on the center two barrels almost all of the time he gets pretty good gas mileage. He used to run a 780 CFM Holley on an Edelbrock Performer RPM and said his mileage didn't change when he converted to the Tri-power. Even when you lean on it it's like having a good size Holley on your engine. Remember though, when all is said and done, it's much easier to set up a good ole' Holley 4bbl (or any 4bbl for that matter) than a multiple carb system.

 

We don't have emission tests here anymore so I can't help much in that department. My guess is it wouldn't be any different than any other setup as long as you didn't have to run at full throttle. Since, in most cases they don't check for NOx, you can most likely pass if you advance the timing and lean the car out (but not until it miss-fires!). Usually, the high compression engines do pretty good on emission tests since they tend to burn the fuel more completely than a low compression engine.

 

Hope this helps.

Link to comment
Share on other sites

Guest Locutus

Texas only has emmissions testing in 3 counties, Harris(Houston), Travis(Dallas/FW), and the 3rd one I am not sure. but its got to be either Austin or San Antonio. My understading was pending legislation was shot down by George W. Bush because if only 18% of the cars are causing high emmisions, then why bother the other 82%. I know this isn't on the exact up and up, but if you really wanna skirt the emmissions test in texas, get a PO Box in a surrounding county, get your car registered in that county, and get your regular plain jane inspection done. Right now its any car that is 24 years or younger.

since most of texas is rural, and these old ranchers won't stand for having to buy new trucks to pass emmisions and trust me these guys run texas, they have alot of clout. of course you could do like I do, and register your car in your parents address, and use it for insurance as well

Link to comment
Share on other sites

quote:

Originally posted by Locutus:

Texas only has emmissions testing in 3 counties, Harris(Houston), Travis(Dallas/FW), and the 3rd one I am not sure. but its got to be either Austin or San Antonio. My understading was pending legislation was shot down by George W. Bush because if only 18% of the cars are causing high emmisions, then why bother the other 82%. I know this isn't on the exact up and up, but if you really wanna skirt the emmissions test in texas, get a PO Box in a surrounding county, get your car registered in that county, and get your regular plain jane inspection done. Right now its any car that is 24 years or younger.

since most of texas is rural, and these old ranchers won't stand for having to buy new trucks to pass emmisions and trust me these guys run texas, they have alot of clout. of course you could do like I do, and register your car in your parents address, and use it for insurance as well

 

Locutus is right but Denton county Collin county and the others will be covered under the proposed emissions crap. Anything near DFW and I think Houston area are bound to be included.

 

 

:} Meat .... it does a body good.

Link to comment
Share on other sites

I had to go find it but the July 1998 edition of "Street Rodder" magazine has a great article on the Tri-power setup called "Triple Play". If you library has old magazines you might want to check it out. Covers everything you have to do in detail.

 

They replaced a 650 CFM 4bbl (no brand mentioned) and mainfold on a reasonably stout Chevy in a 1,700 lbs T-Bucket with an Automotion Tri-power setup.

 

The results were "0-60 times were virtually identical but when it came to mileage, the advantage went to the three two's by a significant margin - we picked up over one mile per gallon. However, we have a hunch we could destroy that number by listening to the carbs, as they sound great when they're all wide open!"

 

Loads of street rods run Tri-power setups so I would check with them if there is a club in your area.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...