bradyzq

Thanks for the advice. I already have a Blaster coil, a Crane optical electronic ignition (which I now see I did not itemize in my first post. Thanks for that!), and am aware of the tach differences. I can live without a tach for awhile. I will probably end up with some Speedhut bits later on. The real benefit should come from the correct timing curve for the setup I have, as well as a stronger, more consistent spark.

Can't see the pics, but I'm guessing that your car is not 918 Orange, but rather the 110 Perismmon orange/red. All these came with white interiors. On the IZCC page, it says that 918 Orange cars were available with white interiors in 1972, but I've never seen one either.

Aaaaaaannnd????? How'd the dyno session go? Did you have a chance to get the MJ dialed in? I am hoping you have significantly more low-end torque than with the dizzy. Enquiring minds want to know!

Rear carb flooding/leaking/overflowing.

I seem to remember, after sandblasting and painting some door hinges from a 280Z for my 240Z, that the early hinges are threaded whereas the later ones are not. This was a looooong time ago, so I may have it backwards, but there is a difference.

Hi All, I've had my 240Z (first car I ever bought) since May 1990, and drove it daily in the summer for years. Over the last few years, sadly, I have not driven it. This project thread is partly designed to get me off my butt and get her running again. It really shouldn't take much (he said....). Here's a bit of what's on the car: triple Weber 40DCOE18's MSA 6-1 headers 1980 280ZX 5-speed 200SX 4.11:1 R180 diff 2.5 inch exhaust with vertical dual tip Euro springs big swaybar and poly bushings all around 4Runner front calipers on solid discs Basically, the usual stuff one would have done over the years. I currently having a rear carb that is flooding over badly. Once I take them all apart and clean them well, replacing gaskets along the way, she should be ready to go, maybe with a new needle and seat and/or a new float. The interesting thing is that I was recently given an Electromotive HPV-1 programmable ignition. I can't wait to find out if it works (remember what I paid for it...) and, assuming it does, tune it. Right now, I have the stock 240Z distributor. So carbs and ignition are likely the first 2 items on the list, followed by a ported head I've had sitting on a shelf for well over a decade. I have a couple of L28 bottom ends, so that might happen when the head goes on. My goal is to get her running and tuned with the HPV ignition by year-end. Here are a few pics I took recently as motivation!

I love the car. Looks like an SR-71 on wheels. Not that it was implied, but this project is only Nissan - powered. Apparently, nobody wanted to get onboard with such a radical project, and they were able to get in late in the game.

Now that the trigger wheel and sensor are mounted...... is the Megajolt up and running yet? I am very curious as to how it will transform the drivability of your Weber setup!

I can confirm that water or coolant can most definitely kill widebands. A head gasket let go on the dyno once and the AFR on the wideband instantly showed 30:1 or higher, and wouldn't come back down on any other car afterwards. You can try removing it and heating/cleaning it with a propane torch, but that has worked for me only for a short time, and not very often....

Yeah, without heat mine might have needed 50 tons of pressure!

Mine each took about 14 tons of pressure in a big press, and they didn't come out smoothly. Every time the pin moved, the whole world shook very loudly! All this was while the whole strut was still attached. Thanks for bringing those memories back!

SDS phone tech support is great. I've called them a few times, and got nothing but useful friendly info. And you can run an SDS using TPS as load (Alpha-N). You are getting all kinds of bad info from your tuners.

Since he welded the cranks anyways, can't you just turn one 90 degrees?

Not the best shot to show the exhaust, but here it is anyways....

I fully admit that EGR is not my area of expertise, and "non-combustible" should perhaps be replaced with "much less combustible." Other than that, aren't we saying the same thing? With EGR active, the percentage of oxygen available for combustion within the overall mixture is lower than when the EGR is not active, therefore, for a given mass of "air," requiring less fuel to maintain a given AFR. Is this not what Tony described in his ECU swapping example? With the "much less combustible" EGR component of the overall mixture diluting the rest of the mixture, it causes the burn rate to slow because of lower combustible mixture density. The resulting slower burn rate now requires more ignition advance to attain MBT.

I look at EGR as effectively making the engine smaller. If you introduce non-combustible spent exhaust gases into the combustion chamber, there is less room for fresh mixture, so it will require less fuel as a result.

I will add a Plan 1C (which was implied above): Estimated cost ~ $1000-$1500 Pull L28 apart and blueprint block. Have machine work done only if necessary. (generally it's better to re-use bearings and such if they're within spec, as aftermarket pieces aren't always what they crack up to be). Do basic headwork on the N42. Unshroud the valves, blend the bowl mildly, lift the upper wall of the intake port a bit, port match the intake manifold. Throw in a decent cam Install decent exhaust Purchase Megasquirt 2 Install and tune it The range is larger than in Plan 1 because you have options with MS2, such as getting rid of the distributor and running wasted spark ignition. The cost goes up a bit if you get the car pro tuned on a dyno vs. doing it yourself.

Well, it's a pull unless it's not. Then it's steady-state tuning. I do both. Which car would you rather have? One that runs well for 30 laps, and NOT BLOW UP before need a refuel Or one that runs well for 40 laps, DOESN'T BLOW UP EITHER, and then needs refueling. Benefits of the 2nd car include saving money, being able to run a car lighter in a sprint race, maybe cutting out one refueling stop in a longer one, having a bigger pit stop window of opportunity. Do you think fuel economy mattered to Audi when they were preparing the TDIs for LeMans? Just a little, perhaps. That's an extreme example, I know. But my point is still: why have needless fuel waste when you can have a safe tune that is more economical even at WOT? Regarding the widebands: Most retail widebands use Bosch sensors. Most controllers don't naturally follow the Bosch sensor's curve very well, and as a result, aren't that accurate in some areas even when calibrated. That is just the wideband itself introducing the error. When you add in all of the other variables mentioned earlier, the error can get even larger. So, yet again, all I'm saying is that you should use the resulting numbers intelligently. Don't give the absolute number too much weight in your tuning decisions. BS IAT math? LOL! It's called the Ideal Gas Law, and it's actually the direct basis of all speed-density fuel tuning. YOU have to understand that if, as a tuner, one gets a reputation for damaging/blowing up engines on the dyno or later, then that tuner's career is going to be short. You also have to understand that my dyno is MY huge investment. I work hard for my money too, and I have yet to see a car on my dyno with an engine that costs nearly as much as the dyno. I also understand that every customer's car is his/her baby. If it's a Honda with an ebay turbo kit or a quarter million dollar race car, the customer and the car get my respect. If this is not the case at the OP's tuner, then for that reason alone, changing tuners would be a good idea. Regarding everything else, I am sticking to my suggestions.

Aha, 5 second pulls. Yeah, you're not gonna load up anything with those. How about 15 second plus pulls, sometimes back-to-back, or even steady state (holding a fixed load and RPM) tuning as high as possible? That's what I meant, and that's what I do. You need some decent fans for that, but it's worth it in that customers' cars tend not to blow up out in the real world after they're tuned! Again, I'll reiterate that I am not suggesting that a car should be tuned on the lean ragged edge. I am saying that 12.3:1 on one wideband can be in the 11's (or maybe 13!) on another, depending on fuel type, sensor health, placement, calibration, exhaust tip, or exhaust leaks. So don't give the number itself too much weight when you have a dyno (and maybe some knock listening device) to tell you a more complete story. If you're out on the road or track, I guess you're a bit stuck, and have to rely more on the wideband's numbers. But isn't that why you go to a dyno tuner in the first place, to get the complete story?

I am.

Hi again all, I wrote this last night but hybridz went down for awhile and I couldn't post it: You should care because it means the tuner has not optimized the tune. Right, and I suggested that that is the wrong approach. You can do the fuel IAT compensation mathematically then tweak it for extremes and engine protection. IAT timing trim can be done however conservatively you like. At least the ECU will begin its compensations from a well-tuned starting point. And what condition would that be? If it's not related to the tune (as in fuel pressure drop, dying injector, spark issues, etc) then a little extra fuel is not likely to save your engine. If the ECU doesn't know about a problem, it can't compensate for it. And, right, a good loading dyno (Dyno Dynamics in this case, I think) cannot simulate real world conditions. It can load the car even harder than it would ever be loaded on the street/track. So if you can't make it knock on the dyno, it shouldn't knock on the track/street. By doing "what the dyno tells me," I mean noting where gains do or don't occur and tweaking the tune accordingly. It's not always where we think, either. And, when tuning, I am in complete control of the dyno and tune, and, to a large extent the entire car. Don't know quite what you mean by this. The dyno, nor my Rice Krispies, would never tell me just to turn up the boost on an overfueled, under-advanced tune! I will proudly make the same power as you while using less boost, but an optimized tune. I will create less heat, and stress the engine and turbo less too. These are good things when on track or on highway rampages, and, ironically, actually help prevent knock. Regarding power, I simply believed what the OP said his tuner told him. All I am trying to say is that 12.3:1 is just a couple of numbers. As we all agree, many things can affect what numbers pop out of the wideband other than actual changes in combustion. Who knows what the "real" ratio is? This is why I suggested that one should trust the dyno. If it's making more power with no knock, you're going in the right direction. Please do not read into this that I am suggesting you run on the lean ragged edge "just because." That is as silly as running way too rich "just because." OP, I am sticking to my position that if the car is running well, then the AFR numbers themselves are nothing to worry about. Get your tuner to dial in those fuel and spark trims, as well as the knock control and it should (hopefully) cost you nothing more, certainly less than if you took the car to a new tuner.

More clarification: Wideband readings vary, sometimes a lot. It also depends where they are mounted, and, if needed, how they are calibrated. Tailpipe probes may show leaner at low load, and if there is an exhaust leak. So, taking that into account, I do what the dyno tells me to do. If it makes more power with no negatives (like knock) at a leaner AFR, then usually I'll leave it there. Same thing with timing. Sometimes you can get scared of advancing the timing past a certain number. But if you do and find the best result is, for example, at 7 degrees past the previous "certain number," you are getting the most out of the engine, and would never have gotten there if you had followed the collective "wisdom."

Assuming the tuner in Charlotte knew what he was doing, at least in a general way, what is the point of paying him (and thinking of paying another tuner for more work) if you don't trust his tune when he's done? Re: detonation avoidance techniques, I would suggest that getting the timing dialed in is how you want to go about it, rather than adding too much fuel to compensate for over-advanced timing. From the OP's comments, it sounds like the tuner experimented with different AFRs, so he must have shown at least some interest in optimizing the tune. I'm not saying that the tune in the car is the best ever. Rather, that richening up the high boost areas by 10% just "because" when there are no hints of a problem and with unknown ignition and fuel trim tables, is not good. The result will be a loss in power and an increase in fuel consumption.

Hi All, Disclaimer: I am a tuner! $700 for a full tune is not expensive if it REALLY IS a full tune. 4 working hours on the dyno is a reasonable estimate assuming no issues are encountered. Yes, of course we don't want our engines to blow up, but flooding it with 10+% excess fuel as a buffer instead of fixing the compensation tables makes NO sense to me. Also, does your car run well? If so, what's the issue? 12.3:1 by itself means nothing, and, by itself, is nothing to worry about. If I were you, I would call my existing tuner, ask him about the 12.3:1 AFR at WOT, the flat timing curve, and the knock control. When dyno tuning, you usually want it off. If he gives you good answers and the car is running well, you're golden and it won't cost you another cent!

I reread Leon's recent posts, my replies, the White Paper, and I owe you an apology. I for some reason was focusing only on the first test, and not the two together, as you and Keith Franck intended it. Perform both tests and you will have a valid read on the situation. Sorry I made your life a bit more difficult than it need be!