LeonV

Bigger is better, if your engine can support it. An L28 with an aggressive cam can easily run 45s. Basically, if (when) I decide to get some new carbs and I have the option between 40 and 45, I'm going with 45.

To recap the last week or two of my quest to rid myself of the sudden-open-throttle hesitation: 1. Tried stiffer pump springs. They seemed to help my hesitation but they were so stiff that they overwhelmed the throttle return springs (new ones) and didn't let it drop back to idle. 2. I replaced the pump springs with my old ones but soldered up my bleed back jets. The setup was 40 pumps and 55 bleeds, and was now 4- pumps and zero bleed. It drove better with less hesitation, but it was still there when suddenly going WOT and sometimes when rev-matching. 3. Keith sent me some .53mm pump jets and a drill bit to upsize to .61mm if necessary, as well as some slightly stiffer springs. Holy cow, what a difference!!! The rev-matching and WOT at low rpm hesitation is gone! Once in a while I'll get a short lag in power output because of AFR going lean, but no more bucking-bronco take-offs. Not only that, but my idle is at 14:1 and cruise is 13-13.5:1 (I want this leaner). It feels so much better to drive this car now. My current accel pump setup is stock springs, 53 pumps and zero bleed. I'm thinking I may need some leaner hypojets to get the cruise AFR where I want it. It's close but I want it leaner, at 14.5:1 or higher. I might as well try the slightly stiffer accel pump springs to see if they eliminate some mixture lag, but I won't want to use them if they mess with the throttles returning. I'd rather upsize the pump jets. All in all, you can barely tell this thing is carburetted now (especially if you don't look at the AFR meter )!

Looks awesome, Rob! Can't go wrong with Panasports...

Nice job, the modelling is coming along great!

Rob, I may be picking up some new triples in the future as well. For the L28 I plan to build, I plan to go with the 45DCOE152. Why? 'Cause they're bigger!

Those can come off in high-rpm situations, but lower-rpm situations aren't out of the question. Checking valve lash should be your first order of business. BTW, you can turn the engine over by putting the transmission into high-gear and simply pushing the car. This is how I do my valve adjustments, no tools or switches needed.

Ask Dave: http://www.classiczcars.com/forums/member7498.html

Beautiful! I love seeing the intricate details of the Z432s.

A 225/50-16 should fit fine on a 16X7 and have no clearance issue, even with stock suspension. Having the correct offset goes without saying.

I agree, I don't think flooding is a concern. I should have said, keeping the throttle closed (on a carburetted engine) while doing a compression test will suck more fuel into the cylinder. Whether that floods the cylinder or not depends on how long it takes the operator to perform the comp check. EFI and round-top SUs will not care how many times you pump the pedal between tests. Triples, 4-barrels and other carbs with accel pumps will...

Don't quote that site, there are tons of misconceptions in there, especially the Weber section.

Triple Webers don't have a ported vacuum source, that's a hose to nowhere. You could try using the vac advance referenced to manifold vacuum but don't expect the results to be great. You'll likely end up with static timing too retarded, thus limiting WOT performance. FWIW, tailoring a spark-advance curve to an engine is not trivial.

A carburetted vehicle will flood, if you keep the throttle closed. At WOT, the vacuum signal is not sufficient to draw out an appreciable amount of fuel. It's SOP, throttle must be wide open in order to get proper, repeatable readings.

Yes, throttle must be WOT. I've disconnected the fuel lines before to do this, but in reality, with the pedal floored and the starter cranking the engine, there is no way it'll have enough of a vacuum signal to draw enough fuel to start, let alone flood the engine. All plugs out, WOT, and you're good to go. FWIW, EFI cars usually engage a "flood-clear" mode if you floor the throttle while cranking, meaning injector PW goes to zero. EDIT: I see that the OP has a 280Z. Refer to L-Jet EFI guys above for why "flooding" is not a problem.

That's a pretty "mild" cam. It has a bit more lift and duration than stock but nothing dramatic. It would probably get you a little bit more top end without sacrificing mid-range and idle. I bet it wouldn't change the engine's behavior much at all. Looks like they kept the lift low enough to re-use the stock valve springs (EDIT: although for whatever reason, they say to only use the specified springs).

Have you checked to make sure all mounting fasteners are tight? Make sure that all driveshaft, diff mount and trans mount bolts are torqued to spec.

Plenty of people. e.g. http://forums.hybridz.org/index.php/topic/79649-progress-on-my-insane-vq35hr-240z-project/

Correct. FWIW, OER uses Weber jets.

Did you install the e-tube with the air-holes towards the bottom?

Pun intended?

To clear this up, as Keith already told you on SDC, that is the dry jet. It goes on top of the e-tube and underneath the holder.

That's exactly what I was going to advise. Do this first, do not resort to vice-grips on the nut right away. It'll make your life easier!

To corroborate Rob, Keith said they're double the spring rate. This should activate the accel pump sooner and give it a stronger shot.

I'm not sure exactly, I didn't get one in the package since I only got springs from Keith. He may have put it in accidentally. Does it have any holes when looking at it straight-on?

Rob, that is great to hear, now I really want to get home and try them out! The stumbling at sudden throttle input (e.g. quick, rev-matched downshifts) has been my biggest gripe.