Hi,

I recently upgraded exhaust. New headers, 2 1/2 pipe, and new air filters. Car runs great when cold. I think not enough gas is getting in now that we increased the irr flow. Can this be adjusted? Do I need new larger jets? Any help would be appreciated. Car is a 72', all original. I am the third owner, have all the receipts from day one!! Bill of sale, window sticker, really cool stuff. Car runs and drives great, just trying to give it a liitle more boost. Thanks guys, email me at gcwhitwell@yahoo.com or reply to the thread.

Gordon

Hi and welcome! Sounds like you have a good find there. I got my 1 owner '71 about 3 years ago. It also came with a log of every fill-up, tune-up and maintenance done to the car since day one. It's really nice to have that kind of history for an old car.

Yes, you can adjust the air mixture. The best thing you can do is buy the video from Z Therapy: http://www.ztherapy.com/

It explains everything. Well worth the price!

Good luck,

Marty

Marty,

Thanks very much for the info, will look into the video. Trying to get pictures up of the car for all to see.

Gordon

gordo , go to the forum section and then to the tech section . do a search for adjust SUs there is a step by step on how to adjust the carbs. This area is a treasure trove of informaiton from members on all sorts of things , take the time to check it out . gary

Hi Gordon, welcome to the club! There is a lot of information to be found on this site by using the search function. And, there are a lot of knowledgeable Z enthusiasts, too!

I've got a '73 with round top carbs, MSA 3-2 header and MSA 2-1/2" turbo exhaust system. My Z is an automatic, so not a zippy as a manual car, but it will get up and go pretty well, especially if I manually shift it!

The SU carbs are basically vacuum operated devices. The different vacuum conditions, which are based on the engine (idle, acceleration, deceleration, etc...), determine how much air and fuel will be drawn through the carb by varying the height of the suction piston in the carb. So, it is somewhat self adjusting.

The SU carbs are simple in design and operation, and there isn't a lot to change; however, you could experiment with different fuel needles. From what I've read, there are different tapers which will affect the air/fuel ratio. Another way to vary the air/fuel ratio would be to change the float drop, but this probably isn't a good way to go about it.

You could also try different viscosity oils in the carb damper. The recommended oil is 20 wt. A heavier oil would cause the damper to rise slower, which would give a richer mixture during acceleration. This might give you a little more pep when taking off from a stop.

If you really want to have better acceleration off the line, consider changing the differential to a higher gear ratio, like 3.9 or 4.11.

Keep us posted with what you try and how it works for you!

gordo , go to the forum section and then to the tech section . do a search for adjust SUs there is a step by step on how to adjust the carbs. This area is a treasure trove of informaiton from members on all sorts of things , take the time to check it out . gary

I'm not seeing a "tech" or technical heading in the forum section. Please point me in the right direction.

Thanks, Gary S.

Gary S. I will contact you with a PM

Found it LOOK UNDER ARTICLES FROM OUR MEMBERS GO TO PAGE 3 AND SCROLL DOWN TO ADJUSTING SUs If you go to the bottom of this page to the forum jump look in there for technical articles then to articles written by members on page 3 scroll down to the SU thread