BRAAP

WOW!!!!! Thank you for the extremely thorough and DETIALED write up with step by step procedures that went into the custom portions of your project. I think is one of the first MS-II N/A Z cars I’ve read about…. Good work…

Combustion chamber volume came out to 55.5 CC. Just waiting on the lash pads to arrive for final assembly, then packaging and then ship it to the UK.

Silent, Your custom N-47 head is in process as I mentioned previously and I will be posting pics of the progress within the next week or so. BTW, how’s that new LS powered toy treating you? You may want to consider at least a little squeeze for the Z if you want it to be quicker than the new toy… At least wit the Z you’ll be able to steer with the throttle… YEE HAA….

Not much to update tonight. This last week and last weekend has been hectic so we fell behind again, (seems to be a common theme around here lately). Any how Ian’s cylinder head has been surfaced top and bottom and being as my die grinder got away from me while working the port entrances and left “cutter tracks” across the intake/exhaust manifold mating surface, I surfaced that as well at no additional charge, (I love how the L-6 looks when all 3 surfaces have been cut and all the threaded holes have been tapped and chamfered…) As for lash pads, .190, .180, .170, and .160 all worked well with this Rebello cam keeping the wipe pattern safely on the rocker arm. I chose the .170 pads as that cheated the wipe pattern slightly rearward from the middle without being real aggressive. Those lash pads are on order, and if they are in stock, (fingers crossed), your head could ship as early as Aug 28th, or sometime during that week. I’ll have Chamber volumes Saturday and hopefully some updated pics of the CC’ing process as well as the clean surfaced head.

Justin, Ferrea valves are a VERY good choice, quality materials, first rate craftsmanship, etc. Finding aftermarket valves for the P-79/P-90 heads isn’t easy, and Ferrea valves are first rate. Chamber work for the larger valves would be same as with the smaller valves, scribe the fire ring of the head gasket to be used on the deck surface of the head, then unshroud the valves out to that point, (pic below shows the scribe line surrounding the chamber of a P-90 head we are working on currently). What work that needs to be done different when going to larger valves is opening up the throat of the valve seat itself, (i.e. making its ID larger), to take advantage of the ports ability to flow more air from the larger valve head diameter. Even when we retain the OE valves on performance heads, we are able to open up the ID Of the valve seat throat by approx 1mm. A larger valve allows for just that much larger seat throat. If the block is disassembled, you could even “eye-brow” the block int eh region of the valves out the head gasket fire ring as well, but be sure not to “eye-brow” below where the top piston ring rides…

“Typical” valve lash measurements are checked at the “cam to rocker” interface. Non typical cams such as the cams that we sell from Rebello and the Racer Brown cam you mentioned, the valve lash is measured at the “rocker tip to lash pad” interface, (i.e. in geometry speak, at the "tip of the valve" vs at the "cam lobe". The latter requires specialized feeler gauges, i.e. modified feeler gauges that will fit under the tip of the rocker arm yet between the uprights of the lash pad itself. Hope this helps, Paul (BRAAP) Ruschman

Most of you are already used to my “excess” babbling… so for those of you not accustomed to it, I do apologize … From a true performance stand point, the OE EFI intakes are a bit weak. The runners have small diameter runners which are “the” restriction to making decent power, boosted or N/A. Sure they can be made to “look pretty” and will flow fine for stock to mild street performance, but that is about it. FWIW, some of the Turbo intakes I have personally measured do have slightly larger ID runners than the N/A intakes but don’t get all excited as that slightly larger ID is just that, SLIGHT! Not large enough to actually FEEL the difference, seat of the pants. If you are wanting maximum effort from your EFI L-series, look into a custom intake. Spork makes a nice unit, 1 fast Z also makes a high flowing ITB set up, or custom fab your own. One idea would be to modify an SU intake set up for EFI utilizing dual throttle valves and port match those manifolds and you’d be far better off from a performance stand point than the OE EFI intake manifold. I have cleaned up more than few of these OE L-series EFI intakes, and sure they look pretty, but for all out performance, they are not our first or even our second choice… This OE ’75 N-42 intake is on my personal L-28 powered 240-Z race car currently. I machined it for aftermarket C-4 Corvette 21 lb/hr O-ring injectors and set it up with a 60mm Nissan Throttle body and cable actuation. This a Flat top L-28 with a custom Rusch Motorsports Maxima N-47 w/L-28 intake valves, 5 angle valve geometry, a mild 487” lift cam. The WOT Air Fuel Ratio is dialed in dead nuts with 100-LL Av-Gas and a very aggressive ignition advance curve dialed into the DIS ign set up and it is noticeably lacking in top end torque compared to the triple carb set up that this EFI system replaced. Next season, we will be installing the IR intake manifold pictured converted to accept O-ring injectors… ITB Intake to be converted to EFI and installed next season… My $.02 on “Mega Squirt” vs “SDS” EMS. MEGA SQUIRT! Mega squirt is actually quite powerful, versatile, and chocked full of features at an INCREDIBLE price, especially when you consider its features. But this very inexpensive monetary price does come at another cost… The end user/purchaser still has to deal with interpreting MS speak, then configuring the MS software, (Megatune is the way to go, but it can also be very intimidating for a person who is not very computer savvy). For MS to function, all the “i”s must be dotted and all the “t”s crossed so that it will function, and when those conditions are met, it functions very well. I currently just went through this myself with Mega Squirt on my L-28 powered F-prepared Solo-II Z. I like to consider myself at least slightly above average in regards to getting around a PC and manipulating files etc within Windows, but with all the options I wanted to utilize from my MS project, it was a bit daunting for me to say the least. Ron Tyler can attest to my frustration of the “unknown” in regards to MS during the set up process. Thank goodness that I purchased a preassemble MS from a reputable builder, RS Autosport. My Z car MS project is currently up and running with distributor-less ign controlled by Mega Squirt and I am VERY satisfied with it. What a fun toy the MS system is. (details of this conversions can be read/seen here… http://www.msefi.com/viewtopic.php?t=15436 SDS! Now, SDS on the other hand requires a bit more cash outlay from the get go, but it is also is much simpler in design and control as there is no software language to endure, i.e. no Lap top to interface with, just a hand held controller. When I say “SDS is simpler”, I mean that from every aspect of the term. SDS is a GREAT “Race car”, “Boat”, or “Air Craft” EMS. For a street car, SDS is only satisfactory, compared to all the available systems today, the SDS is lacking in features regarding transitional performance, etc. It lends itself to home built air craft, boats, Drag/Bonneville race cars perfectly with its dependability and simplicity. Don’t get me wrong, I absolutely LOVE SDS. I have swapped numerous E-mails with Ross Farnham, (owner of SDS), covering DIS for V-8 systems back in the late ‘90’s, (and BTW, Ross is great). Back then, SDS was at the top of their game, but the EMS market has evolved by leaps and bounds since then and SDS hasn’t really stayed with this growth curve, and it is my opinion that unless SDS makes some drastic changes to their systems in the near future, they could end up becoming to the EMS world what DOS is to PC’s, obsolete and only for the die hard boat and home built air craft guys. I would really hate to see that happen. Another rapidly growing EMS system is the WOLF 3d system. They are priced comparable to SDS but in its current production run, it has the control and features of MOTEC and top of the line AEM systems. When it comes to stand alone EMS, the current irritation of Wolf 3d has the most bang for the buck, of course that is just my opinion. Ron Tyler is currently setting up two separate Datsun L-28 powered Z cars with COP, (6 individual GM LS-x coils) utilizing WOLF 3d. For more info on the powerful yet affordable current production Wolf 3d EMS, you can contact Ron directly at ron@primeems.com One of Ron’s COP set ups…

The information I’m about to give was given to me by a reputable and valued member of this forum and hopefully he’ll chime in, (please Cary McC?), as there is a good chance that my memory of this conversation back in the early ‘90’s has become distorted… Cary and his father did rev the bejeezers out of the L-series, no matter if it was a mild street Z or a full blown Race Z, That is how they drove, that I do remember as accurate. Cary still revs the snot of whatever he runs on course, LOL. Any how, I remember him mentioning that they did break more than a couple L-series cranks. If my memory serves, he said that the OE Datsun L-28 crank is good for 8500-8700 RPM MAX! At that point the crank will break right at the rear main. As I remember this conversation, he said running as light a flywheel as possible and a quality heavy a damper on the front allowed for the most RPM before failure occurred, such as a FluiDamper modified to fit the L-crank. The crank would break right at the rear main separating the flywheel from the engine. That is all I recall from that conversation at one of the local events back in the early ‘90’s. Hopefully he’ll see this thread and chime in…

You can also take an old .010” feeler gauge and using a pair of tin snips, cut up several small pieces that will fit within the spring retainer under the lash pad. As a matter fact, I just sent out a couple of lash pads and a few snippets of .010” feeler gauge to Hybrid member less then 2 weeks ago so that he can order the proper lash pads for his set up. Even a few pieces of .020” and .030” cut up for those really wild set ups is good idea to keep the stacking of .010” shims to a minimum, (Lash pads are sold in .010” increments). This approach to finding lash pad thickness works very well, especially for those only going through this process maybe once or twice a year. Side note, Sears sells their Craftsman Feeler gage sets for under $6, That and at least one known lash pad, (say .160”), is a very cheap complete lash pad checking set up. Much less expensive purchasing one example of all the available lash pads and is just as accurate. Hope this helps…

Ooops. Midwest, sorry bout that Silent. We’ll post more updates this coming weekend, sorry nothing this week.

OOpps. I forget to answer the rest of your questions… For final finishing, do NOT use stones. Never uses stones on aluminum and never grind aluminum on a grinding wheel. The stones/grinding wheel can and will explode if grinding/carving aluminum. Aluminum clogs the stones like you are experiencing with your cutters, but when stones/grinding wheels clog with aluminum and then gets really hot due to continued use,(Aluminum expands when it gets hot), it causes the bonding agents within the stone to come loose and at the speeds the stones/grinding wheels spin at, it literally grenades and the end result is usually a trip to the ER. Not good. Sanding wraps as pictured in the link I mentioned above is what you should use. As for how far to take the finish inside the runners themselves… I take it this is an EFI intake manifold, and as such, this is what is called a DRY manifold, i.e. there is no fuel flowing through it, just air. Dry intakes can be mirror finish smooth. A totally polished finish requires LOTS of time and there is a place in this polishing process that we all deem the point of diminishing returns. This point of diminishing returns varies on the individuals patience and available time. With a fine sanding wrap finish inside of your intake manifold on even a hot street engine, you’d be hard pressed to get a measurable increase in HP on the dyno if you spent the time to completely polish it, though if it were completely polished, that would be ideal scenario for a dry intake, as I mentioned, it is debatable whether it is worth the time and energy. As for the intake ports in the head, these are essentially “wet” at approx. half way down and as such, HP gains by leaving a little texture vs a totally polished surface is one of those “6-one, half dozen the other”, propositions. For race “only”, and if you have the time, polished is what you should strive for as the throttle will be at WOT most of the time so the port velocity will be high any way. For street applications where part throttle response should be considered, at least, somewhat important, traditional wisdom dictates that an “as cast” or similar finish in the port would be ideal. But once again, on the dyno, you’d be hard pressed to measure a gain that is substantial enough to warrant the effort put forth. My personal opinion on the DIY port finish… There are MANY other areas of the engine build and tune that would benefit from that kind of effort and attention which could yield much greater gains… But then again, you can never pay too much attention to “ALL” of the details when building your engine. The more attention to detail you pay, the bigger your rewards… Hope this helps…

First off, your choice of using Carbide for your cutters is a GOOD one. Carbide lasts MUCH longer than high speed steel, carbide also allows for a faster cutting speed. Sure, the initial cost for carbide is a little more, but if you do much carving at all, in the long run, Carbide cutters end up costing less than half that of high sped steel cutters and carbide allows you to work faster which also saves time. In short, if you are at all serious about carving or porting, think “carbide” only. For carving on aluminum theses cutters ARE different than what is used for carving on iron. The gap of the flutes, the included angle of the cutting edge itself etc. When shopping for cutters for carving on Aluminum, they are generally referred to as cutters for “Non Ferrous” materials. These cutters will carve pretty much any material as the name implies, (which implies SOFT non ferrous metals such as brass, aluminum, magnesium, etc. Non magnetic stainless does NOT fall into this category). In short, you need cutters for “non ferrous” metals. They are a little better at “self cleaning” and will also cut with much more authority. If you use these “non ferrous” cutting bits on ferrous metals, they will dull rapidly. Also, cutter tip speed is critical in regards to cutter life and clogging. In “the machinist hand book”, there is a formula for calculating this, but for our DIY projects, typically, a carbide cutter spinning at 20,000 RPM and hogging aggressively on the soft Datsun heads and intake manifolds will cause the cutters to clog. The slower the cutter spins, the less it will clog. A quality die grinder that allows for variable speed is the E-ticket. Other wise, you can get an air valve to attach inline with the air inlet of your die grinder and you can regulate the air flow that way, (in the picture linked below of my die grinders and cutters, my “hog” die grinder has this adjustable restrictor on the air inlet). Also, there is wax available that porters use while porting for extending periods. Just dip your cutter into the wax periodically. This helps keeps the cutter cool so the aluminum wont get stuck in-between the flutes so often and also helps to extend tool life. Another “bubba” trick is to have a nice soft piece of cast iron laying around, say an old Chevy iron block that has little to no nickel in it. When the cutter starts to clog, just run the cutter firmly against the cast iron and that will purge the cutter of the stuck aluminum. This will shorten the cutters life, but is quite effective. In this thread is a picture I posted of several cutting bits for ferrous and non ferrous bits approx 2/3 the way down the first page. http://forums.hybridz.org/showthread.php?t=110269 Hope this helps…

Ok. Due to the secrecy of the PINKS project up to the day the race aired, the custom P-90 cylinder head that we built for that project had to be kept on the down low, which was at the time I posted those pics. Now that the race is over, I can let the cat out of the bag. The head that we shipped that week was actually indeed the P-90 head for the PINKS project… Here it is, the PINKS P-90, just prior to assembly… BTW, Garret, (The PINKS driver), informed me that the car ran 124+ MPH trap speed… YEE HAAA…

If you are having troubles getting lash pads, give us a try. Being as we specialize in custom Datsun L-series cylinder heads, we usually don’t have much trouble getting ANY of the available thickness of lash pads, though sometimes they may be a week out for oddball ones, but hat has been the worst case. Paul Ruschman ruschmotorsports@hotmail.com

I’m back!?!?!… Performed a “c:format” on my PC, reinstalled Winders XP, made some fine tuning adjustments for a more refined interface between the keyboard, mouse, my eye balls, and all the goodies stored on the hard drive. All in all, it went very well. I’d agree that the Sharpie or Dykem is probably a better choice than the non drying Prussian blue, mainly because the sharpie isn’t so thick and wont “drag” as the cam approaches the and leaves the wiping surface leaving a false or distorted smear across the wiping pad.

Every cam is different. For certian, the aggresiveness of the lobe profile is the major contributing factor, the more aggresive the lobe profile, the more wiping surface it wil ltake up. Also, the region that is responsible for the "lash take up", on the opening and clsoing ramps of the lobes are ground with differing rates from different cam manufacturers/grinders. Some cams are noisy no matter what the lash is set at, (an indication that the cam grinder paid little to no attention to detail in regards to the the lobe profile itself, "lift jerk" curves are more than likely out of whack and in a worst case scenario could cause undue valve float, premature cam and rocker wear, or just a cam that doesn't perform as good as it specs suggest it shuold). Well, I'm performing a "format C:" on my PC in the next few mintues, so if I dont respond again within the next day or so, you'll know why...

You have PLENTY of room left on “both” sides. Good job btw. If that were my daily driver L-series, I’d call that perfect and not try to adjust or cheat the wipe pattern at all. If you are one of those guys trying to extract every last “oz/lb” of power, you could very well cheat the geometry towards the back side of the rocker, (towards the bottom in your pictures), by using a thinner lash pad. This “cheating” essentially increases the ratio of the rocker slightly by altering its ratio between the cam lobe, pivot and valet stem, giving the valve just a skosh more lift and a frog hairs more duration. For most daily driven street cars, it is debatable if the extra 1-3 hp is even with the trouble, and depending on how radical of angle the rocker sets the more vale train noise that can be induced as well. Judging by how narrow the wipe pattern of your cam is to begin with, if you wanted to cheat the wipe pattern, you might even be able to get away with as thin as. 160” lash pad. A word of caution for those wanting to do this. If you do cheat your cams wipe pattern, make absolutely sure on each and every rocker that you are not going over the edge of the wiping surface itself, i.e. check the wipe patter of each and every rocker, and then make sure you put those rockers in the same place you measure them from as the rockers are not all machined the exact same. As you can see in this picture, the wipe pattern of this .580” lift Schneider cam doesn’t leave much room for moving the wipe pattern around as it pretty much used more than 90% of the available wiping surface. This sort of gives you an idea of how close to the edge you can safely get the wipe pattern.

I concur and also back up “1 fast Z” 100% on this.

Brian, I agree that it is the difference made, as measured on the flow bench, and how it is interpreted that really counts. As I mentioned, we will post our gains in the near future. You mentioned CNC for cutting seats? That would be very cool. Are you incorporating CNC port work into that as well? BTW, I sent you an E-mail.. Flames187, If you are going to school and involved in an F-SAE project, then you would have, or should have, access to the SAE books that should have the most in-depth info in print regarding Helmoltz tuning. As you mentioned, there are so many variations of formulas for calculating ideal intake runner length and diameter for a given displacement and within a given RPM range that it really muddies the waters. I haven’t the foggiest which to use or why. Ah. I have an idea. IF you have a report for school that you have to do, maybe you could research that and post your findings? The SAE books would be great place to start. I’m sure I am not the only one here that would love learn more about this.

Ian, Ah yes, we do have that warm fuzzy feeling with this head. The other head that we didn’t get that feeling from is destined to be used for further L-series head development, possibly sectioned up, mapped, etc… As for numbers, no guys, sorry I do not have any numbers, “yet”. We will be running some of the more popular chamber and port configs soon and most likely will post those, but only to satisfy the numbers/math geeks among us. In regards to port flow figures. It is in my opinion, and the opinion of many other professional engine builders, that quoted Flow Bench flow numbers as given to customers, are only given for the purpose of their records, just as the bearing clearances, torque values, etc. quoted on an engine build sheet are given. The flow numbers are not numbers that should be used to compare one heads theoretical possibility to produce any sort of power to another head. A lot of guys like to compare flow numbers of heads and most people automatically assume that bigger numbers are better and mean more power. Generally speaking, that thought holds some truth, but not all of the time. The flow numbers derived from a flow bench are just static flow numbers only and do not reflect how much power an engine will produce, or how it will produce power within its intended rev range, i.e. torque under the curve. If you are comparing flow numbers while bench racing with your buddy, you may as well be comparing torque values for your Rod Bolts while your at it. Then when you want to compare something tangible, compare dyno sheets or ¼ mile time slips. You can take two identical cylinder heads that are ported differently, but flow pretty much the same CFM on a flow bench at the various valve lifts. Put these heads on identical short blocks and one engine could very easily make considerably more peak power than the other, and they will both have distinctly differing power curves as well. A flow bench can NOT measure all the variables taking place on a running engine such as the rapid opening and closing of the valves and the pressures that build from this surging air flow, (I just wrote an article about this very thing in this thread towards the bottom of the page http://forums.hybridz.org/showthread.php?t=108398&page=3 ). A flow bench does not take into account the fluid dynamics and pressures of the spent hot exhaust gasses. A flow bench does not take into account the cylinder scavenging during valve overlap. Material removed during porting from different areas of the ports and chambers will have differing affects under running conditions that a flow bench just can’t measure or tell you about. A flow bench is a valuable tool that when used by competent experienced engine builders, can help shorten the learning curve to producing maximum effort engines. The Flow Bench is a tool to be used by the engine builder himself, to get an idea of what port/chamber mods made a change, and he should also not assume that all changes that allowed for more air flow will allow that engine to produce more power, or better yet, more “useable power” for its intended application. The info derived from the flow bench should only be used by the engine builder, and as a very rough guide, not gospel. One head that flows more than another could actually produce less power due to the variables that a Flow bench can’t measure. In short, either a dyno sheet or a ¼ mile time slip coupled with the vehicles weight, are the real tests of what an engine can or can not do, not the flow numbers from a flow bench. The Flow bench is just another valuable “tool” in the engine builders tool box.

The seats have been cut. Next step is to blend in the chamber wall cut and the bowl hog to the ports, then surface the head, CC the chambers, pre assemble for valve train set up, etc. etc. etc. In the past, I have tried to get pictures capturing the different angles that are cut with the seat cutters but none of the previous pics really represented what was going on, very well. This time, I think I was able to take a decent shot of the seat work we perform using the Sunnen VSC seat cutters. I just LOVE these seat cutters for their precision, repeatability, finish quality of the seat face itself, etc. This first picture shows the cylinder head set up on the mill table with the cutting pilot installed in an intake guide. I then use the finger dial indicator and run it up and down the full length of the pilot in two directions to square the “head of the mill” to within .0001” of the pilot which is true in the guide. This keeps the “mill head” true to the valve guide so that the valve seat will be cut “square” to the valve stem, not tilted or canted. I then spin the finger indicator around the pilot to center up the cylinder head perfectly under the mill head, within .0001”. This allows me to cut the valve seat itself to within .0005” concentricity to the valve guide, (not offset to one side). Now I lock the mill table down tight, then double check all of my runouts in “X”, “Y” and “Z” just to make that tightening the table down didn’t disturb the settings, which it sometimes does when you are trying to keep such tight tolerances. This procedure is done for each and every valve seat that I cut. You may have seen or heard about a “seat & guide machine”. Serdi and DCM both make quality sat and guide machines. The seat and guide machine itself replaces the Bridgeport style mill that I use for performing seat and guide work, even though it uses the same cutting systems that we use here on the mill. A seat and guide machine is much quicker as its sets up much faster, but uses a bubble level and you are trusting that the table is plumb to mother earth, (or you should be double checking it once in while at least). I’ve used a DCM in the past. They are very convenient and are typically accurate enough for even high end production shops, as long as the operating is keeping tabs on the table/bed being level. This approach of using the knee mill is more precise even though it takes a little longer. With the mill, I know for darn sure that on each and every seat that I cut, that I am dead nuts on. This next picture shows one of the chambers with an Intake and an Exhaust valve. The valves themselves have purple lines on the seat faces to help identify the face and back cuts. The face is ground at roughly 44-44.5 degrees and the 30 back cut is 30 degrees to aid the air flow transition from the back side of the valve to the seat at low valve lifts, less than .100” lift. On the valve seats in the head, I marked the angles in green, with the offset green mark being the actual 45 degree valve seat face itself. The intake on this head has 5 angles, the exhaust has 4 angles. I try and get 5 angles as often as I can, but several factors dictate if I am even able to or not, such as new seats, valve head size, etc. With every head that we do, we are able to open the throat of the valve seat itself at least .040” sometimes as much as .060” over OE. This is like going to a larger valve without actually installing the larger valve itself. This modification is really only good for really high valve lift flow, at low valve lift, it doesn’t help. Of course actually installing a larger valve allows me to open the throat of the seat even further, but for most mild to moderate street L-series, this is not needed. For the Intake seat, the top angle in the chamber is 15 degree, then 30, then the 45 degree seat itself, then 60, then 70, then the bowl hog cutter which is the Blue marks, (the bowl hog is either 75 or 80 degrees, I forget which, forgive my poor memory), and then the port walls themselves. For the Exhaust seat, the top angle is 30 degree, then the 45 seat itself, the 60 degree, then the 70 degree and then the bowl hog. The green circle just left of the intake seat is the chamber wall relief cut which radiuses the 15 degree cut into the chamber wall and roof, (the 15 degree and chamber radius is actually on one cutter, as well as the 30, 45, and 60 degree cutter). On pretty much all of the valve seats we cut for N/A applications, whether it be Briggs and Stratton’s, Datsun L-series, or Little Block Chevy, we cut the Intake seats at .040” in width, and all the exhaust seats at .060” in width. Also, all of the Intake and Exhaust seats are exactly the same diameter as one another respectively and they are also cut to within .002”-.003” depth of each other respectively. On some boosted applications, we will cut the exhaust seats at .080” in width, this is application dependant. Of course, if the customer has specific seat geometry he/she needs to meet, we try to accommodate the best we can. Whew, back to work…

EXACTLY! I’m glad I’m not the only one whos L-28 was so finicky that it had to have separate summer and winter resistors. LOL A bone stock L-28 will tolerate quite a spread in AFR, but the more finely tuned for performance the engine is, the more finicky it becomes to AFR and even fuel quality. Finicky enough that during extreme temp swings from morning to the afternoon on some days, the engine will have slight misfires that you can ever so slightly feel/hear unless you reset your values. There is a little air temp sensor in the AFM, (that little white probe-nub looking doohickey), that is supposed to compensate for air density caused by temp variations, and it does a great job on stock engines, but for finely tuned performance cars, the ECU needs to have a more aggressive adjustment MAP in regards to that little sensor. FWIW, that little sensor in the AFM works just like the water temp sender, and that little air temp sender responds VERY VERY fast. It responds so fast in fact, I have used it as a tire pyrometer with a DMM. I did this back in the early ‘90’s. I just attached it to the end of an old ball point pen with the leads coming out of the back of the pen. I didn’t get actual temp values, (though it would be easy to calibrate it for that), I just used it to check for misalignment of toe and camber at the track when I used to run my cheesy 195 60HR 14” daily driver tires… (those were the days… LOL). have we gotten far enough off topic yet? LOL. I just love these discussions that get off on interesting tangents.

Oliver, You should not have any issue with running the resister in the cabin. In fact, the little black box sits on the center console for on the fly tuning/diagnosing. I was able to get in to Rons car to get picture of the little black box sitting on his center console, just in ahead of the 280 Z ash tray. Not that it has any relevance to what you are doing, but as for “ball park” OE water temp sender values, when the engine is dead cold, ambient temp of 70 degrees, the water temp sender value is typically between 2500-3000 ohms. With the engine at full operating temp, approx 180 degrees F, water temp sender value is typically 250-350 ohms.

Great thread to revisit. I may have missed it and if I did, I apologize for being redundant, but in regards to “sealing” the back of the car, I saw no mention of sealing the latch under the hatch and behind the license plate. These are areas that exhaust fumes from behind the car come into the rear hatch area via the vinyl interior cover of the underside of the hatch itself. Back in the early to mid ‘90’s when I had the dual exhaust on my L-28 powered 280-Z exiting out of the OE rear bumper holes, only about 2” out past the rear valance, I did get fair amount of exhaust fumes in the car. I had no fin, wing etc, see pic below… When I swapped in the V-8, I retained this exhaust arrangement, except it was dual 2.5” instead of dual 2”. So I set out to seal the back of car 100% from any air flow in or out. What I mean by the “back of the car” is the entire rear valence/taillight area. At first I recognized that even if the taillights are sealed good, and the rear hatch sea itself is in good condition, that the exhaust fumes can easily get behind the license plate and between the hatch and body itself, then up through the hatch lock, and into the space between the outer and inner hatch skin and ultimately into the interior through vinyl covering that allows access the hatch lock mechanism. In the first picture using a parts car as the example, the upper circle is the area between the hatch and the body of the car that needs to be sealed, (the bottom picture shows one method of using weathering strip to do just that). The lower green circle in the upper picture shows the latch hook as it is behind the license plate which allows exhaust fumes up into the hatch itself. (These pics are of a 280, the 240 would be similar). On my personal Z car back in the day, I just used duct tape to seal off the latch hook under the license plate. This is the BUBBA way out, but it did help. I’m sure that someone could easily make a Fiber Glass cup that could easily be attached under the license plate to seal that off, of course make it removable to be able to make hatch hook adjustments. Just thought I’d throw out my $.02