Chino 240Z

I just recalled reading this from your link in your first post. If the mixture screw is more than 2 1/2 turns out turns then the idle jet is too lean (too small). When the mixture screw is less than 1 1/2 then the Idle jet is too rich (too large). These assumptions are based on the fact that the speed screw setting is not opened more than 1 1/2 turns. If the speed screw has to be opened 2 or more turns then this is also an indication of a lean condition usually requiring greater change. At times it may appear to be showing signs of richness or flooding it is really a lean condition. See pictures and notes in the tech 2 article supplied in the kit instructions, view and please understand the need to keep throttle plate as near to closed as possible so as not to prematurely expose the transition holes. This is what causes the visible rich condition, and confirms the need to increase the jet size. JET KITS are available if needed. EXAMPLE With the speed screw set at no more than two (2) turns in after contact with the stop lever; and the best idle occurring with the mixture screw set at 3 turns from bottom, indicates the need for a larger Idle jet. Achieving the best idle at under 2 turns indicates the need for a smaller idle jet. The secret to understanding the critical nature of the carburetor set up and the advantages of a WEBER over other carburetors is the idle circuit. Referred to as the low speed circuit by Weber, this circuit is responsible for 80% of the driving operation. This is the reason that the Weber should give a fuel economy improvement over most factory carbs along with significant performance gains. In the worst case you should not see a significant fuel economy loss over stock, while improving HP & Drivability. Sounds like you still don't have the right jetting.

I have a set of triple webers on manifolds in the shed and that is were they remain ever since I got the ZTherapy SU video tapes. I've had Webers on a sandrail many years ago. I don't know what changes or direction you have gone in by the jets & tubes you have listed. Sorry. But as for the dieseling in a carburated car: What is happening is that the throttle is remaining partially "open" when the engine is shut down, which gives the hot engine sufficient fuel to run without a spark from the spark plugs. Most hot engines have sufficient carbon build-up that remains glowing red hot and acts as an igniter for the fuel. The solution is to make sure that the throttle closes completely (your butterflies in the carbs) when you turn off the ignition switch. Check the throttle stop and make sure that the fast idle on the choke or the "bottom stop" isn't what is stopping the throttle from closing. Rich mixture with a little too much open butterfly on one or more of the carbs may be giving you the dieseling problem? It could be just the too rich a mixture has caused carbon build up in the chambers, and a hot piece of carbon in a combustion chamber is the ignition source. In that case, lean it out, lower the idle a tad, and put a can of good carbon cleaner in the gas tank, such as GM's Carbon-X, or Chevron's Techron. Even though the can of "stuff" says you can pour it down the carburetor, it's better to let it burn off slowly. Even if your neighbor says to pour water down the carb, don't. Cold water (or chemicals) makes valve stems look like pretzels, and the steam washes the oil off, not a good thing to do. And then there's always the possibility of causing a chunk of carbon breaking off and getting stuck where it does lots of damage. On my daily driver Firebird I burn Chevron gas with that Techron additive, and sometimes put a bottle of Techron cleaner from Parts store, in the tank. Don't think you'll get rid of carbon build up over night but over time this may help. Or this would be something that you can clean up if someday the head needs to come off.

If your running a stock motor, I would start with making sure you have things at factory settings like your timing. Several things can cause dieseling too- cheap gas, hot spot-carbon on piston, improper head & block temps from bad <a style='text-decoration: none; border-bottom: 3px double;' href="http://www.serverlogic3.com/lm/rtl3.asp?si=24&k=water%20cooling" onmouseover="window.status='<a style='text-decoration: none; border-bottom: 3px double;' href="http://www.serverlogic3.com/lm/rtl3.asp?si=24&k=water%20cooling" onmouseover="window.status='water cooling'; return true;" onmouseout="window.status=''; return true;">water cooling</a>'; return true;" onmouseout="window.status=''; return true;">water cooling</a> system, timing. It's not out of the question that issues in other places can make your tuning more difficult. Are these new webers going on? or existing webers needing service? Did you have each of these problems before using the synchrometer, or did you get the meter to help you with problems you've had for some time?

As for SU's you would be adjusting or balancing the airflow between the 2 carbs at idle by comparing with the meter. You would want to get the best or highest idle by adjusting your mixture first, then balance the 2 carbs to flow the same amount of air at idle by adjusting the butterfly screw on each carb, not fuel mixture. Not sure if Webers would be the same in this manner or not? I would think your backfire is caused by mixture, not idle airflow. Remember the carbs and engine temps need to be at normal operating temp to get best results from your adjustments. Let's see isn't it, rich condition backfire out the exhaust and lean condition most likely to backfire up the carbs, if I remember right? This is why I feel SU's are easier without all those jets to deal with.

I often use this site to compare manufactures sizes, ratings, and <a style='text-decoration: none; border-bottom: 3px double;' href="http://www.serverlogic3.com/lm/rtl3.asp?si=24&k=customer%20reviews" onmouseover="window.status='customer reviews'; return true;" onmouseout="window.status=''; return true;">customer reviews</a>. I like the price & performance of the Toyo Proxes RA1 225/50/14, good track tire. http://www.1010tires.com/tire.asp?tirebrand=Toyo&tiremodel=Proxes+RA%2D1 or if you prefer drag racing? http://www.1010tires.com/tire.asp?tirebrand=BFGoodrich&tiremodel=g%2DForce+T%2FA+Drag+Radial Each Mfg. may not have the same sizes, but close.

We have really like the life and performance of the Toyo RA1s (245/50/14s). Between my wife and I we log about 350 hot lap miles in a day. The set I have on now have about 1125 miles, even wear, no chunking, very predicable, no signs of giving up lap times yet (Actually getting faster) I shave em as I wear em. I keep the wear even by rotating them off the rims. Not fender to fender racing, but rather opentrack events every other month, so the abuse my be less. I think there's still have another 1000miles to go.

I liked the book. Each motor builder will have their own ideas, several ways to skin a cat. This is a good guide as to what one can expect in building for HP and good aspects that you or your engine builder should address.

Don't know if this will download for some slower dial-ups, but some guys that went to the March 16th event at WSIR made a funny video with the Top Gun theme. No Zs in it but gives you an idea of the fun. Hope this works, http://www.pricerev.com/ts-movie.wmv

You betcha Byunique, you can sit back a replay your hot lapping over and over again anytime you like! Good Z memories. There is a self inspection check list posted on their site that you go over your car with sign and send in with your registration. But yes, your car should be in good working order anyways. Even though this is a very fast track, braking here is not that bad and not as extreme as other tracks. You will find that by the end of the day you will be doing less and less braking as you get acustom or use to the track. No one has ever talked about sound restriction at WSIR yet. Our exhaust is one of the louder cars and we do just fine there. There are some pretty loud monster V8s that show up to run with no problems so far (knock on wood). Laguna is known for shutting down loud cars, that's too bad. I know I would have to put on the baffle to visit Laguna, even then ours might be too loud.

Perhaps you could ask around to barrow a helmet, even a motorcycle hemet would get you in. They don't demand one, but if you do buy one, the SA2000 certified hemets are they rating that you would want for automobiles, and this the latest rating update. Long sleeve T-shirt, pants and closed toe shoes will be fine. We do the whole suit thing but that is because we are little more serious than just a one time deal. There are other organizations we play with that require the complete safety wear. This group is not fender to fender racing, only passing in the straights, but the Red (fast) group has alittle more freedom. If you go, you won't regret the time & money spent. It is just plain awesome, and by the end of the day you will be drained! We often skip a session so not do over drive our limits and we put double time on the car with 2 drivers. Street tires are fine, you will hear and feel their limits better than race tires 1st time out. There will be instructors doing lead follow slowly for the 1st session then later on you can have them go out with you and ride as passenger in some of the faster cars. Mrs. Chino-Cindy is doing just that next time with an instructor to picking up some new secrets to kick my butt! You will have a new respect for driving on the streets after you do an event such as this, I did, I slowed down on the streets. I'm mailing in my payment for the 2 of us. Weather should be good, and you're welcome to hang out with us for some extra help around the place. Craig

If you are interested in taking your Z out onto the Fastest Track in the West? come on out to Willow Springs International Raceway on May 11 in Palmdale, California. Sign ups and other info is found here. http://www.opentrackracing.com/ $145.00 gets you a morning drivers meeting & instruction, [5] 1/2 hour sessions for each run group (beginner, intermediate, advance), BBQ lunch and a T-shirt. If you are interested check it out or give me PM if you have questions. Caution: this kind of fun is addicting! Craig & Cindy.

Don't know, but as often as I run the car, don't let oil leak, never in the water or rain, should last a life time. Looked like the original, but it workin now.

"Carl, No, I had no trouble removing the nuts on the 2 studs that are on the diff cover...." Your not the only one, Friday night at midnight- Damn those things are tight! Cindy handed me the torch and after about lighting my britches on fire under the car!...I warmed the nuts up and they came right off. The new diff had bolts instead of the stud & nuts, much easier. Anyways I wouldn't advise the flame under the car thing, you're only asking for trouble, but it was getting late! Craig

Couple months ago on the track, while going through the gears hard, noticed extreme hard hitting drive train. (Okay, so I get over excited and shift too hard.) But after lifting the car and pushing up on the rear of the trans. I found a softened and broken trans. mount. This is what you can do to check the mount. It has rubber insulator built into it for vibration dampening, oil and age will weaken the mount and will let the rear of the trans move too much. It is about a 15 to 20 min. change out with the car up while you support the rear of the trans with a jack and bolt in a new unit. I think Victoria British had a much better price than MSA? but MSA was closer to me. Be careful getting under the car, use good jackstands, but you should be able to make the change. Craig

"We don't need no stinking badges!" Shave it!

Konnichi wa Terd San! Enjoy the ride.

Hey Ron, bring this sweet ride out to Opentrackracing @ WSIR on May 11th! All you can drive & eat for $145.00 the big track! This is the last run until after summer, should sell out fast. We're there!

In the Fontana District you still have to go to a location to take a final test after you do the online time. So I thought I would go and do all the time & test at once and get it over with. In our district there is a Judge that will reduce the bail or fine amount if you go to court and ask. He is quite popular. Reductions from $300-$400 tickets, down to $88-$125. You just gotta look nice, show respect and ask. That's not much to do to reduce you fines. You might look into this in your area Bill. Make a couple phone calls to the traffic courts to find out? Good Luck. Craig

Chin Up Bill, I just did my traffic (Laugh & Learn) school Sat. from 8:30 - 4:30 @ $25.00, Bail amount I paid was $124.00. 75MPH in a 65MPH on the 10FWY. I only sped to pass a gravel truck dropping gravel then back to 65MPH at 5:30AM, "but you're right officer I was speeding!"

Hi Tex. Dude, Depending on the electric fuel pump the PO put in? you may need to see if there is a fuel pressure regulator in line to knock down the pressure? above say 4 to 5 psi is too high, depending on the size of the fuel lines? If you are around 3.5 to 4 psi the Su fuel bowl float valves should be able to control the pressure and not over fill the fuel bowls. You may need to check the float level and adjust according, and or the 2 SUs need to be sycronized and fuel adjusted too? Fuel level in the side fuel bowls are rather critical to getting a SU to tune right. You basically need the fuel level in the bowl set right, then the needle jet adjusting nut under the carb is the final fine tuning of the fuel. So, yes you may need some carb. adjustments but I don't think that is your problem. Bad carb setup may be adding or compounding the problem. If you feel you want to twist on the carbs, check out some of the threads regarding SU tuning, there should be lots here to read from. Craig

EScanlon, thanks! I just wet my pants laughing!