Lazeum

I fully agree with your comments I was giving an example thou. A friend was advising me a regular WB with no RPM reading for instance. I did not follow his advice, I'm glad I made the right choice The Innovate LC-1 is WB where you plug a gauge to read it. You can also datalog with it. I haven't chosen this route, I don't know how it works precisely.

Logs could be more than useful. If you do a WOT pull to check AFR at full throttle, you'd better look at the road and keep your hands on the steering wheels. here is an example of what I've got with my setup (which will need some correction ) http://www.servimg.com/image_preview.php?i=183&u=11056344 Most likely a setup such as Innovate LC1 WB with a gauge would work well. AEM WB would work as well. Those are very nice unit.

I like the innovate system as well. If you want to learn more, I would spend some time on the Innovate forum. http://www.innovatemotorsports.com/ I've got the LM-2 system and I'm a noob with WB. It is a very good tool. Their software is free to download on their website with some examples if you want to check further more. http://www.innovatemotorsports.com/support.php It also depends as well of your needs. Do you want one to get logs once in a while, be able to help friends, permanently in the car with a gauge, etc. Are you going to use it on specific engine/ECU? Some Ecu softwares are compatible with only some brands/models.

I've got mine from UK yesterday It's nice to have "daddy" working in London during the week

Better suspension parts might help but the main contributor to car behavior is the geometry. Dependng of the geometry many variables will change such as: - Caster (for high speed stability vs. Vivacity) - Camber vs. Suspension Stroke (If you're in full compression stroke, how the car will handle since left and right side geometry is different?) - Toe in vs. Suspension Stroke (ditto, stability/vivacity will change according to suspension stroke) - Steering angle variation vs. Steering angle (what kind of feedback in the steering wheel do you want? - You want it stable with curve at high speed and very quick with slow steering change) To change this, you'll need a new steering gear... Most of those criteria can be very hard to change. What we can do is to make the car stiffer to be more reactive and to improve the feeling of the driver. You can also play with Camber angle, Toe in angle. With stiff suspension, variation will be reduced anyway but you've never get completely rid of the initial characteristics of the car IMHO.

I placed an order for some main jets, accelerator pump jets and 2.00mm needle valve (with Fast Road Cars eBay shop you've mentionned earlier). As soon as the weather allows me to drive my car I'll do some trials. It is cold (kind of 32-45ºF) but it doesn't snow much, there's no more salt now on roads I've also received the advance curve kit from Mallory to play with timing. For sure, I'll keep posting updates on the board.

I just came back from a trip to the Z storage house (parents ) I've checked the needle valve, the accelerator pump jet as well as the fuel height. - the accelerator pump jets are actually 40 (quite small compared to what I've read) - The needle valve is 1.75mm The fuel height is waaaay out of specs. The floats are 26g (brass). With measurement made with vertical cover I have: - Fully open: 4.5mm instead of 8.5 - Close (floats pad flush to the needle valve with no pressure: 8mm - All the way: 12mm instead of 14-15mm btw, after 2 weeks without running the bowl was almost empty with no gas in it. Is it normal? (the bottom of the bowl seems to be dirty, I might check fuel filter) So could we still say the needle valve are too big in my case and might not close soon enough creating the rich spot? I would say NO. Actually I'm leaning toward the usage of a smaller one if I'd have to change anything... The fuel level is then 4-5mm too high. This would make the mixture even leaner if I correct the height to be in spec. I have checked only one carb, others might be different but I ran out of time... I would believe I need to increase main jet size prior to play with the floats in order to keep the AFR in the good/safe range for my engine. Since I have wideband, that might be the safest and most convenient way to proceed. Regarding the progression circuit. I have 50f9. Idle mixture screws are 1.25 turn from fully close as Weber books advice with very reasonnable and smooth idle. When I accelerate normally (off throttle to WOT is more than 0.5s at 3000rpm at least) the engine reacts fine. When I floor it super fast as I did for the AFR logs, you come up with the curve you could have seen. In normal conditions, I don't experience the stumble I've done during measurements. I will increase first the timing to be OK (from 10º to 18º-20º) and see how it goes. If problem still exists, I start with the accelerator pump jet but I might have to change idle jet with new timing. There're still some work to do!

Regarding needle valve, I've read this is (not only ) In another word, it makes me think our rich/lean conditions could come from the needle valve too big in my case, it does not close enough quickly enough the flow in the bowl and create the rich spot I experience. I guess it is going to be an easy check worth a removal of the top cover of the carb This is going the same way the guys on innovate forum talked about to solve the rich/lean mid rpm condition. By playing with the height of the fuel might solve the problem. Actually I believe it will move the problem somewhere else instead of fixing it.

Whan I look again at your AFR, you're right. You both seem to lean out after ~4k rpm. I would agree with you regarding fuel starvation. On my side, the AFR curve is really flat but I do have a rich spot at 4k rpm. I would have on my side to go with a bigger main anyway since I'm at 13.5 on the most part of the curve in addition to very low timing to be reworked (10º initial/ 28º total)

Have you look at carefully? There's plenty of info on the board... Anyway, I've been thru this process with my tires and rims. Take the stock size as reference (left dimensions) and compare with your wheels on the following link. Be careful with the offset too. Rims-n-tires.com For your info, I had 215/45-17 yoko ES100 with 17x7" rim with +42mm offset and 35mm spacers that fit right on my 240z.

I believe it is the opposite; we have too much gas and not enough air at 4500rpm range but problem might be the same... Between Emulsion tube/float height/needle valve, that's a lot of options to check, to inspect, to see and to solve our problem Everything look simple on books

That's a lot of good info coming up We start to have more and more AFR reading about Webers. The weber noob I am does not know how to ckeck needle valve. Should remove the float cover? I would have to do some more investigation since I've never tried to take apart the cover yet. Other observation is that you do not have the rich spot as we have with Mark and many others over internet (Actually it is the opposite) Should be interesting to try needle valve as well (maybe ours are too big and fill up too much the well with vacuum at certain RPM)

Mark, on the following link, They seem to believe float level is having a big impact on when the main circuit starts to act and it can improves our rich spot. However, it is happening at 4500rpm; way after the mains start to pour gas so I'm a little confused. The interesting thing, the spot happens with my setup (L28, 32mm choke), Mark's setup (L31, big choke) and Innovate forum OP (1600cc honda engine, 45DCOE and 38mm choke). So we can eliminate choke size, DCOE type, air/main jets since our setups are all different regarding those items. It seems the spot is not related with the emulsion tubes. It seems weird to me since they are the features that control behavior of the richness over the rpm range. I'm not completely sure to understand in detail how emulsion tube works. I do understand the slowing process with air bubble but does the level of fuel into the emulsion tube chamber change with vacuum? Should we try an emulsion tube with different type of holes in the middle of the tube then since our rich spot happens in the middle of the rpm range? I would have to look at emulsion tubes blue prints to check richness difference vs. tube design. They put salt on the roads today I might have to wait before to do any test but I would think I can give a try with the wideband to see the impact of float level (with 1mm change for instance).

Scott- How do you setup the float height? Do you bend something? I've seen many picture showing how to measure but nothing to know to chnage settings...

I'm planning, before to change everything, to record dyno curves and AFR curves So far, dyno measurements haven't been very successful but I'm making progress (I'm going to use an inductive pickup on spark wire or most probably on coil wire to get higher amps reading) I've also spotted some leaks between carbs and intake. I don't know yet if it is coming from the choke not being off completely or leak at seals (maybe due to my mistake of overtorquing the carbs on the manifold in the past) For sure, I'll post my results (good or bad ) Matt

Just for fun, I left Michigan for France this year. Here gas is at 1.25€/Liter => 5.9 $/gallon with a €/$ rate of 1.25

That is great info, Mark! The bad point is the F2 emulsion tube did not help to lean the rich spot as hoped. I'm still confused about it, why do we see it? Could it be related to choke (venturis) diameter? Emulsion tubes? Auxiliary venturis? Others? I'm in the order of looking for some extra jets and emulsion tubes. I was going to give a try with F16... Weather is now cold and rainy but as soon as it is going to be better, I'll try to make some progress on my side as well. I'm learning a lot so far, it's great My car is runnung better and better! Regarding choke size to be as small as possible, I kind of disagree. Around my town, there are only twisty roads, the fun is in the high revs also. Reasonable choke size is nice to have to push the engine a little. I would believe max torque would be best at 4000rpm for road car. btw, nice numbers on the dyno

I fixed my detonation issue I've lowered the advance timing. I'm now running 10 initial and 28 total. I will adjust the timing, try to shoot for something close to 20 at idle as suggested For my timing story => http://forums.hybridz.org/showthread.php?t=140950 Now that I'm not running a sick engine anymore, I've done some WOT pull AFR logs. This is what I came up with I need to adjust timing first I guess. The car nose dives at the beginning of the pull. We can see when I hit the gas pedal that I start to run rich then very lean before the run rich again afterwards. It seems the accelerator system is not working the way it should (duration + mixture seem out) I've got a rich condition at 4700 to 5200 rpm I do not explain. I would guess it is the emulsion tube. The rest of the curve (flat spots) are a little lean but I guess there are quite ok for now. I'm waiting for your feedback and your thoughts FYI my setup as a reminder: F54 L28, N42 head flat top pistons, 274 Schneider Cam 3x 40DCOE, 2.5" 6-2-1 header/exhaust Mallory ignition (Unilite + Hyfire 6AL) The jettings: Main 130 Air correction 180 Idle Jet 50f9 Emulsion F11 Accelerator pump 50 Venturi (choke) 32mm Aux venturi ??? probably 3.5"

Hey Josh, Actually, I'm running very rich. As far as my full carbs setup, I've got: 3x 40 DCOE Main 130 Air correction 180 Emulsion tube F11 Venturi's 32mm (to be confirmed) Accelerator 50 Idle jet 50F9 see link below for some AFR during a regular drive AFR log the timing light I am using is a no advance Craftman unit. To setup the advance timing, I've used gages to setup the Unilite unit. I did not check with the light total timing. btw, I've order the tuning kit from Mallory with different set of springs, I'll see what I can do with that

I am definitely looking for good response off idle. I'm more looking for a fat torque curve with decent power than for a very high HP number. Scott, Your proposal is very nice but I'm no longer in Michigan (I'm in France, Europe). It is a little over 4h I'll send you a PM about my setup.

Thanks all for the explanation I'll ramp up timing on my car soon and see what I can get out of it. Hopefully I'll be able to get dyno curve before and after.

You would run 24 initial timing? That's 14° over what I have today Am I that far off? Regarding my cam, I have a schneider cam with a duration of 274 if I remember well. For the distributor, I do understand there are 6 sparks per rotation on the distributor vs. 3 ignitions on the engine. Distributor turns 2x lower than the engine z-ya, what was your initial timing? I guess you were having quite a lot of timing. could initial timing be low because of vacuum advance?

What kind of timing is it? Total or advance timing? Since it could be both, I'm confused... 1 Fast Z, it is something I did not think about. I did not run the car long enough to see any unusual high temperature (I drove the car for 15 miles with this setup). I'll definitely check the temp next time I run the car. Being on the very rich side with AFR probably reduces heat a little also, I guess. Regarding timing, I was able in the past to see big improvements with my previous car (Mitsubishi Evolution), I gained 20-30 whp with timing adjustements vs. stock settings.

First of all, thanks guys for your answers. They make me feel better I've checked my timing before the advance timing tweak. I was at 10º at 1k rpm, 25º at 2k rpm and 34º at 3k rpm. I'm using a regular timing light which is not so accurate... A friend of mine is having one with timing correction. I plan to use it as soon as I can. I've checked my AFR as well with a wideband, I'm on the (too) rich side (10 to 12.0 AFR) but before to mess up with the carbs or do anything else with the engine, the detonation had to go. The engine is also freshly rebuilt, it has less than 2000 miles on it. I fully agree with you, it does not make sense otherwise. Finally, I'm not going to leave the engine the way it is. I'm running 93, there's no reason I could not run optimum timing. With no detonation, I'll be able to go little by little to the optimal performance of the setup.

The question is in the title. I have a total timing at high rpm at 28º so far. It could sound stupid but I guess it could make sense in some cases, including mine (I hope!!! ) - My Story - I had knock for some time (actually since I bough it over 1 year ago but I run the car very little so far - 6 months winter did not help) and decided to fix it. It occured only at low rpm (3k / 3.5k rpm) at WOT. FYI, my setup is : L28, flat top pistons, mild cam, N42, 3 DCOE, headers, 6-2-1 2.5" exhaust, Mallory Unilite distributor, Mallory Hyfire 6AL. I decided to back off timing a little to eliminate detonation but I went far enough to have very erratic idle with missings. So I went back a little to run ok. the car was still detonating, the idle timing came at 10/11º. Advance timing set at the factory was untouched: +24º From my readings, total timing at idle should be more at 14-16 and at 34-36 at high rpm. Knowing my car is detonating, I had to play with the distributor timing (probably also with the curve since there was no detonation after 3500rpm). Then this weekend, I setup the advance at 18º (to have 14+18 = 34º). I did not touch anything anymore so far; idle timing is still 10º. The car runs fine with no detonation (!!!!) but does not seem to pull as strong as before (since it is only for some time, it is fine with me). Then the reason why I would like to run like this for some weeks: I want to record with dyno curves the tuning progess (with an inboard sofware I need to tweak first); my Webers are not tuned very well and I want to observe improvements and progress. What do you, guys, think? Can something bad happen to my engine running this way?