zredbaron

stage 8.5 side project: restoration of my rear bumper. copper stage. this was just too cool to see and NOT take a pic of. after this coat came the zinc and then of course the chromium. [yes, those are rust pits, but they are under the rubber parts so i told them not to worry about making it smooth.] after all parts are replated. all new mounting hardware. after assembly. MSA evidently stocks original nissan horizontal rubbers. their vertical over-rider rubbers are crap though (they dimple when tightened, you can see in the pic). don't get them! i also found original nissan chrome bolts and original mounts. lucky me!

stage 8. doors, headlight lenses, hood, hatches are re-attached to the body.

stage 7. door jams, hatch area, and underhood are painted red and clearcoated. underhood is prepped. i didn't ever catch it in the primered stage. the paint booth was big enough to fit 18-wheelers, so i asked if i could hang out in the corner and watch one of the stages of paint. very cool. after the red, before the clearcoat. still wet. i snapped a short video of him in action: and this is where we're at as of Nov 8th. i dropped the car off at the shop on july 1st, so as close as i am, i'm still at least a few weeks out *at best* given the pace of the project.

stage 6. inside of doors and underside of hatch are painted and clear coated. an impressively deep clear coat. makes me wonder what the body will look like! he did a great job cleaning up the belly of the hatch. the outside of john's advertised "race parts" were quite clean, but the undersides weren't nearly as smooth. that said, my painter has some serious skills making this composite part look like smooth metal...

stage 5. the jams are primed. very clean. finally getting somewhere!

stage 4. all windows, doors and rear hatch are removed. jams are gutted and prepped. rear hatch weather stripping being pulled out. the nearly 40 year old oem glue was quite hard to get out. i still don't know what they were thinking with the burnt gold color akin to the 70s. full on bright orange looks beautiful, but burnt gold? bah. i really admired the attention to detail back in the hinge area. the painters hands were all scraped up from jamming bits of sandpaper in tight quarters. they even drilled out the riveted manufacture plate in the door jam. this may or may not be standard for this quality of a job, but i was impressed nonetheless. the rear hatch jams cleared up quite nicely. this is a preview of some of the custom mounting required for the carbon fiber rear hatch. nothing too serious, but that's why it's scraped out the way it is. no idea what the math is. the lower hatch area was one of the only rust places on the car. water pooled up at the bottom of this area as well as a comparable area in the door jams, resulting in some pitting. the new hatch won't be weatherproof, so my Z will likely never see rain again anyways.

stage 3. the body is fully prepped and primered:

stage 2.5. damn while-im-at-it-drug... the set of new koni struts and stiffer springs that have been patiently waiting back in my garage got me wondering if i could fit just a bit more rubber under my fenders. oh, what the hell... let's cut the fender lip. here's what i had them do: cut the lip right where it makes that turn in towards the tire, and instead of have a knife edge cutting my tires, they tack-welded steel brake line onto the edge. the brake line was slit open with a cutting wheel, leaving a nice rounded edge on the bottom side. then they put some fiberglass over the weld: which leaves a very subtle, but open/aggressive look that likely won't be noticed, but leaves more room for rubber nonetheless.

stage 2. here's the new hood after it had been fitted using the oem hinges. i took john's advice and elected to use hood pins to fasten the top of the hood. i wanted to keep the stock look, but the aluminum braces over a plastic rear window isn't exactly subtle. the air dam, rims, and brakes aren't exactly a stock look either. time to give it up, mark... as you can see, the hood has a perfect shape. very impressive for something that's hand-made. quality product, john!

stage 1. after deciding on a shop, the painter utterly refused to paint "just the new parts." he basically told me he didn't care what i paid for, he's going to blend into the fenders. he decided shortly after that to paint the whole fenders. i later came into the shop the and saw this: the circles are pointing out imperfections in the body/paint that the shop would of course not be responsible for. at this point, i'm looking at the car with the shop's body guys and the painter, and the painter of course suggested "dude, all thats left is the doors and the top, you might as well paint the whole car." i go to the office and respond with "make me an offer I can't refuse" but of course the while-i'm-at-it-drug had already dictated that i'd be painting it all.

i suppose i should include the most recent "before" pictures: [be forewarned it may or may not be hard to stomach pictures of this paint utterly destroyed] now i'm sure most of you are asking yourselves what kind of idiot would want to destroy such a nice paint job!? i've asked myself that, too. the truth of the matter is i had a slight boo-boo. and by that i mean my bumper and hood got in a fight with a shrub, and the shrub won. the hood was repairable, the bumper was not. yes, the paint was very nice for the most part. but let's face it, the paint was about 15 years old, believe it or not. there were rust spots under the paint. the corners were chipped and cracked. there were minor scratches, dents and dings all over the car. all rubber on the car was at the end of its life cycle (the rubber was not removed when the car was painted red, so there were imperfections from the painter taping off). i had been eyeing john's carbon fiber parts for some time, but it had always been filed away in some fantasy time period where i had nothing left to do but lighten the car. now i found myself wanting a new hood. i decided to go with john's hood. it was right about here that the "while I'm at it drug" was injected directly into my neck. as you already know, i decided i wanted to get the rear hatch at the same time.

i should have started this thread months ago. oh, well. the project's initial intent was to purchase john coffey's carbon fiber hood and hatch and to get the two panels painted "a close enough match" to the rest of the car. i obviously was looking to lose some weight for autocross, as opposed to infusing a bling bling look into a car from the 70s. not now, not never. no way. (who's chair is that!?) here are the parts as they were shipped from JohnC (ie Beta Motorsports): these parts truly are incredible, btw. the two combined, including the lexan window, weigh in around 10 lbs. the stock hood and hatch (with glass) weighs in at a combined weight of about 95 lbs. one hell of a difference...

the heat shield in this pic was an aluminum plate, crudely cut and bent into shape. the header side has layers of chalk asbestos boards (yes, asbestos!). evidently asbestos has a wondrous resistance to heat transfer and won't catch on fire) screwed into the aluminum plate. fastening the plate to the header wasn't exactly graceful, either. i'm not sure what you call it, but i can describe it: a long, threaded bar (pole/stick?) of metal that i bent and wrapped around the header. threw a couple nuts on it and tightened them, cinching on the header. you can find the threaded bar in home depot for about $5 right next to where you would find angle iron and skinny metal and wooden poles/sticks. some of the skinny round metal poles are threaded and fit a standard nuts like 3/8" or whatever it was. the green strap-like looking piece in the middle was a hangar wire wrapped around the headers to prevent the plate from flapping.

FANTASTIC presentation of data, matt. thank you. nice to see exactly what each change is doing. alas, the rich spot remains. you know my thoughts on that. 2eighTZ4me, i have electromotive ignition as well. my hpv-1 took a dump a few years back and i've since upgraded to the hpv-x. some cool features but more or less the same performance. i'm running a very high end 109 octane VP fuel, so i'm with you there as well. to the discussion about alcohol, yes, there is alcohol in these fuels. there is also alcohol in pump gas. depending on manufacturer and geographic location (ie state laws), both pump and race gas will contain varying degrees of both alcohols and ethers: ethanol, toluene, xylene, etc. whats different in more extreme fuels is the concentrations of the ingredients used to produce the required octane. there are disadvantages of each type and mixture of fuel. i'm by no means a chemist so i won't go further than that. the point of all this is that the suggestion that weird things might be happening when the fuel is emulsified is a very valid theory. the specific gravity of fuel has a significant effect on the emulsification and eventual atomization of the air/fuel mixture. if anyone wants to read more about fuel, go here: http://www.offroaders.com/tech/octane.htm http://www.idavette.net/hib/fuel/ just don't listen to the making your own brew with xylene advice. bad idea. bad on your cars plastic's (ie fuel lines and tank parts) and doesn't perform well or consistently. that said, in my own experience, my car was much smoother when i went to the race gas. i assume this is because it is *engineered* to have a fast flame front and burn well, not to mention the fact that a >= 12.0 compression ratio demands ~104 octane at a minimum. it smells nothing like pump gas, not even a resemblance as it smells very pure and pleasant. my theory is that even with the A/F ratio off significantly, this fuel is going to burn and burn fast in an engine that calls for it. side note, what is so *extreme* about your engine that you need 112 octane fuel? no offense, but your power output is consistent with a street performance motor, not a race motor. (is this your friend's 200sx or a Z?) you may find better results with pump gas in the 91-93 octane range. also, tell us more about the engine. displacement? cam specs? venturi size? since you are going lean, i would start down the fuel delivery investigative path. re-check your floats, inspect your needle valves (like the one's in matt's pics). if those are good, then i agree with the suggestion to toss the fuel pressure regulator and instead invest ~$100 in a good electric pump. you want a high-flow capacity, low pressure centrifugal fuel pump. webers like 3.5-4 psi. don't send any more pressure than that.

i haven't given up the hope that its possible, i've just lost motivation to keep trying. perhaps i'll come back to it, perhaps i won't. who knows. regardless, best of luck to you, and i trust that you'll share your discovery if you ever do figure it out. cheers.

i have an electric fuel pump mounted near the tank. i dont remember the brand, but it is a centrifugal pump that is high-flow, low pressure and cost a pretty penny. if my memory serves, the pressure is in the 3.5 psi neighborhood. of course it *could* be fuel pressure. it could be mixture. it could be timing. it could be cam/block. it could be venturis. it could be floats. it could be anything. we're stabbing in the dark here. we're trying one thing, finding no change, then sprinting to the next idea that produces the "well, maybe..." sentiment. at this point im tired of chasing "hey it might be this..." we may have similar problems in that we both have unexplained dips in the AFR, but yours is minor, and mine is severe. the problem may be in fact be from some problem we have in common, and it may be from a limitation of carbs vs. fuel injection. lets not forget that there are very good reasons that all cars are fuel injected these days. lets face it, there are some very complicated fluid dynamics going on in these wonderful carbs (and they are quite wonderful), and everything we know about them is 'theory.' the designs are no doubt based on many years of experimentation. they can't possibly feed any given engine demand that can be built, can they? i have been chasing this with my wallet for years. i have had hope, promise and eagerness in trying new parts or adjustments, and nothing has helped. the one thing that has been constant is that the more i've upgraded the engine, the worse the dead spot has become. when the block and head were stock L24, the driveablity (and therefore AFR curve) was perfect. after my first round of upgrades, it was still pretty decent. after the next, there was a tricky spot. after the next it was a problem. and now, at race engine, its an abysmal little black hole in the power band that you really have to be patient and know how to finesse your way through. at this point i am inclined to think that we are experiencing a limitation. you have only a minor dip because you have a street performance engine, and my race engine has aggressively exacerbated this condition and created a nearly undriveable rpm window. but hey, my theory can never be proven, only disproven. so unless/until someone can actually fix my dip, we will never know.... i'm simply saying that i have all the parts and and adjustments and tools that i've ever heard of yet i still have no results. dyno, timing (w/vacuum advance), fuel pressure, jetting, flow balance, floats, cold air, etc etc etc. nothing. they all have had an effect of course, but nothing has even masked the problem. these things have simply made the rest of the band run better or not. the answer i hear is FI. that's not to say i'll do it, but that's the only true solution i see....

hey guys. sorry for the delays... hard to stay up on things here in the middle east... i never did have another race before i deployed (the event was cancelled), but i *did* raise the ride height and soften the springs to 3 in the front and 2 in the rear. i think. the car handled wonderfully in comparison. you guys were right; the struts weren't allowing my suspension to do any 'suspending'... even though the car handled light years better, i think i'll be taking the advice to jump up the spring rates and get rid of the illuminas and move to a more proper strut for a purpose built car. i'll be back in the states this summer and intend to experiment with unbolting the rear ARB, too... again, thanks so much for the responses!

well matt, if i could get my curves as "flat" as yours, i think i'd call it a day and be damn proud. your 135 graph looks like your best bet to me. did you not change your airs for your tests? you gotta change those to match your mains.... see what she likes. i'm still deployed in the middle east, but i had the opportunity to use a computer and wanted to report back that i bumped up my needle valves, pump jets, and bumped down the pump bleed jets as well as re-adjusted idles, mains, and airs to suit. all this after fixing my float levels. although the car did like the changes about as much as changing the mains by the minimum increment, the dead spot is unchanged. i am at a loss and at this point i am simply writing it up as incompatibility between carbs and a true race cam/block at a certain rpm range. if i run the car like a race car, i find no such hesitation (ie in the power band rpm range above 4000). i don't know what else to try... -mark

i too have pump jets and needle valves on order. i've also purchased 3 pump bleed jets to tinker with the accell circuit a bit more. but between the needle valves and the floats, we just might get a decent curve... here's hoping... (thanks russell and other contributors, regardless)

yes, this is normal for it to be empty. this is why with an electric fuel pump you wait a couple secs before engaging the starter, and with a mechanical pump it takes a couple turns from the starter before it fires up. you need to prime the fuel lines and carbs. you check the level after driving it, shutting the engine off, then immediately checking the level. the dirtiness you see is likely very, very fine powder-like substance that has been caking on the bottom for years. i had that too, but by all means, check your fuel filter just in case! with regard to the brass float levels, i'd compare your carb stamp to the table on the triumph site if you haven't already.

if i could MOVE the problem to below 2000 rpm (or above 7000 for that matter!) then i wouldn't ever look back... unfortunately i don't think it's quite so simple, but fuel level is obviously a very crucial part of the equation. at least we are heading in what seems to be the right direction for once, matt.

speaking of links, i just found this fantastic article. lots of great info and pics all in one place... http://www.tjwakeman.net/TR/WeberDCOEinfo.htm particularly of note, it shows differences in float settings based on model stamps, discusses some idle adjustments that the books don't (a venturi bypass air screw!?). definitely a must read...

very good. hey, i could be out to lunch, who knows. it *IS* worth a try... let us know how it works out! also of note on that euro site: damn good stuff...

also, thanks russell for your links! i was able to order some new idle jet holders that i've been looking for for a very long time. i think i might buy that 'official' weber manual, too...

there are a lot of things i'm inclined to respond to, but i've been waiting for some road tests before piping back in on that stuff. with regard to advance, i agree that webers like a lot; my initial advance is over 20 (not sure how much MORE is added by my MAP sensor, if any?). i'm 'all in' with 29 at 3k (again, plus mystery MAP sensor advance), then i linearly back off to 23 by 8k (again, + mystery MAP sensor advance). i suspect the mystery advance added is about 5 degrees or so. (a very different engine, though...) i do not at all mean to suggest that needle valves aren't important, but the data speaks for itself. look at my graphs. i don't have a problem with being lean. i have a problem with being rich. i agree with lazeum regarding the a/f graphs. perhaps we are all talking about different sections of the graphs, i'm not sure. i'd like to settle it, though. okay. it's called the "air to fuel ratio." meaning, if the ratio is 14.7:1, there are 14.7 parts air to 1 part fuel. right? so any number above max power mixture (arguably ~12.5-13:1, although stoichiometric is 14.7:1 and is a different discussion entirely) is by definition a lean condition, and any number below max power mixture (again, assuming ~12.5-13:1) would be a rich condition. agreed? there is a MAJOR DIP in my AFR graph (and in your graph, datsnlvrs, though yours is a *very minor* dip) from roughly 3500 to 4500 rpm, and again dipping low after about 6000 rpm. again, a low AFR ratio is a rich condition. i have to say that i completely disagree with your logic. IF we assume that you're right' date=' that you ARE in fact running out of fuel in the jet well at 4500 rpm, then how is it possible that you are going rich above 6000? if you were running out of fuel at 4500, then you would continue to get leaner and leaner as rpms increase (AFR number gets higher). again, both of our graphs do the opposite: they fall. to shift the topic a bit (ie why this happens, so we might troubleshoot in the right direction): here's my line of thinking from my understanding of fluid dynamics (i don't claim to be an engineer, but i do have a fairly decent grasp on aerodynamics). i will compare the progression from 5000 rpm to 7000 rpm for this conceptual discussion (also assuming WOT). as rpms increase, the total volume of air passing through the engine increases. we are talking about carburetors, so we can also submit that *more* fuel from 5000 to 7000 is supposed to be "sucked" in, in order to ideally keep the AFR constant. i put "sucked" in quotations because this is actually incorrect. there is no force in nature that sucks. it is a term of conceptual convenience. the reality is needed for this discussion. the physics of what is going on here is that the pressure INSIDE the venturi goes down RELATIVE to the atmosphere (ie the pressure in your air box). this difference in pressure causes air to flow from high pressure to low pressure; air is PUSHED from the air box into the venturi and ultimately the cylinder. (similar to how water is PUSHED out of a hose; lower pressure is felt on the end of the hose than at the faucet.) there are two things going on here. bernoulli's principle (ie venturi effect) tells us that as the speed of a fluid increases (over the venturi in our case), the dynamic pressure of that fluid decreases. this decrease in pressure is what PUSHES more fuel from our fuel wells, through our jets, and into our venturis (more fuel at 7000 relative to 5000). the other thing thats going on here, is that the air is becoming increasingly turbulent. nomenclature side notes: turbulent air is random in direction and inefficient in terms of flow. think white water rapids. laminar flow is straight and very efficient in terms of flow. think water through a pipe or a hose. comes out clear, not white. [img']http://www.markhaag.com/images/hybridZ/flow.gif[/img] to continue, as rpms increas, velocity increases and therefore the air is becoming increasingly turbulent as it passes through the venturi. (it is likely that low rpms have NO turbulence, as there is a velocity at which flow across a surface changes from laminar to turbulent. [this change is known as stalling in terms of aircraft wings but is caused by other factors.]) as turbulence goes up, the efficiency of flow goes down (and therefore the resistance for flow goes up as turbulence goes up). so, as resistance to flow goes up, more pressure is needed to PUSH the air to maintain a given flow rate. too bad we don't have turbos or superchargers to solve this problem. we still have atmospheric air pushing into our venturis, and it simply can't keep up. however, the relative low pressure is still continues to draw increased amounts of fuel. this is where i believe the air corrector is designed to "correct" for this; displace some of the sent fuel, and send more air in its stead to try and keep the AFR constant. at the dyno the other week, i did change only an air corrector and noted its effect from one run to the next, hoping to flatten the high rpm dip. the frustrating reality was that it did not flatten but merely shifted the graph up or down from about 3500 and above. main jet did the same thing, but also shifted below the pivotal air corrector rpm. this damn carburetor seems like it would take a graduate project at an engineering laboratory to explore fully. sigh. so. the point of all this is simple. in my mind, we have two separate rich-seeking trends on the graph, one at mid-range rpm and one at high rpm. i believe the high rpm problem to be independent of the mid-rpm problem. i suspect the high rpm problem is a limit to carburetors in general, and you can only minimize its effect via the air corrector. i don't think we will ever make it go away. [that's not completely true, a larger venturi would help this problem greatly, but would worsen driveability.] i suspect the low rpm problem is a CAUSED by large venturis, and EXACERBATED by floats/needle valves/jets/timing/etc. but hey, what do i know? i didn't design it. this is just what i believe based on thinking about it. there's probably some weber expert out there in a shack in new mexico that can tune my webers perfectly. it seems the weber engineers were some pretty smart bastards and thought of things most of us don't even know about. that doesn't change the fact that we're all still just getting them 'as close as we can' to tuned. there's a reason carbs don't come on new cars anymore; mechanical things simply have their limitations. -mark