BRAAP

SOOooo.. Cary. When you race are you Auto-ing or Moto-Xing the car, I can see it now. The next generation of “X” games, Cary M. and his double back flip with a half twist in a 240 Z…

Dave, The Air Temp sensor needs to at least be mounted in la ocation that gets "flowing" air across it. The balance tube doesn’t really see “flowing” air, but pulsations back and forth, if that makes any since. Here is thread about the inlet Air temp sensor mounting positions. http://forums.hybridz.org/showthread.php?t=115937 The water temp sensor could easily be threaded into any portion of the cylinder head such as the rear if stealth is your concern. When drilling and tapping the head, just be sure you aren't anywhere near the oil galley or into and combustion chamber etc. Interesting project by the way.

Darius, Can you give us a little more info about your headers? They appear to be stainless. In those pics, the curves and radiuses look generous. Very nice indeed. 1) Are the headers off the shelf and if so, what brand or are they custom one-offs? 2) What are the primary and collector sizes, (looks like maybe 1 7/8” primaries with head adapters?) 3) What heads are you using on this engine? Thanks in advance, Paul

Grumpy, Thanks for your input. As a professional engine builder and tuner myself, I have always had great respect for your writings as pretty much everything that I’ve read from you corresponds to what I’ve learned and apply in my shop. It’s nice to see someone else as passionate about engine building, design, and tuning. I do have one of the low grade laser infra read thermo guns, they are very useful for all kinds of diagnostics, tough one that reads up to 1800 degrees would be nice for that quick cylinder to cylinder EGT comparison check, especially for dyno work. This application will have WOLF system 5 stand alone EFI and I also have an LM-1 wide band O-2 sensor/meter that I use for tuning, (worked great for dialing in the Mega Squirt EFI on my L-6 race car), and I have been kicking around the idea of installing O2 bungs in each primary for measuring cylinder to cylinder AFRs for the reason you stated and being as the Wolf EFI system will allow for individual cylinder trim tuning in both fuel and spark, (plan is to run Coil on Plug ignition similar the LS-x), I will be able to adjust them accordingly. Again, thanks for your input and if you see any areas that looks like a bad move/choice, please don’t hesitate to speak up. Thank you, Paul Ruschman

If you want what you see below, you’ve got a long way to go…. Before you start removing what is there, (that is pretty clean OE set up there by the way), you really should read up on what everything does so that as you start removing items, you’ll have an understanding of what possible compensations you might need to make so you wont induce any issues from the transformation. For the most part, it is straight forward, and depending on far you go, i.e. the pic below, it will take a lot of elbow grease and depending how fast you want it done, how much money you are willing to spend. Good luck…

Talking about the response time of the IAT sensor was really started to dig at me so I went out to the shop and data logged the IAT removed from the intake manifold to see just how fast it would respond to air temp changes using a heat gun and compressed air blowing across the sensor. As I mentioned previously I had hoped that this “open air GM IAT” would have a quick response time and it does. Ron Tyler helped as he handled the heating and cooling chores while I monitored the MS gauges and data-logging… We also found some other interesting info as well as the Temp rate of change. The body of the IAT senor itself will heat soak…. Ambient Temp in the shop was 55 degrees F, initial readings when we powered up MS on the IAT gauge in MS confirmed that 55 degrees. Then while Ron held the IAT by the wire pigtail, he used the heat gun to blow across the IAT and the gauge screamed from 55 degrees to 150+ in a matter of couple seconds. He then removed the heat gun, and the temp reading held steady, no change up or down. He then grabbed the sensor around the metal base, at this time the gauge started to read a nice slow steady decline in temp. Then he grabbed the pigtail again, the temp stabilized right around, 120 or so. Then he blew shop air across the probe and it rapidly dropped till he removed the air at 55 degrees reading. Then we started the data log, added heat, paused, added cooling, stopped the datalog. This pic shows the datalog from 215 seconds to 240 seconds time span, (Time line is at the bottom in aqua color. Each aqua bar along the bottom is 2.1 second intervals, (don’t ask me why it is at 2.1 second interavals, it just is). Starting temp was 55 degrees. The vertical aqua bar is at the point which Ron immediately removed the heat gun, 163 degrees. Heat started at approx 217 seconds, heat removed at 221 seconds, a temp rise of 108 degrees in only 4 seconds. Not instant, but rather quick. From 221 seconds till 231 seconds, Ron just held the sensor by the pigtail, 10 seconds, temp change was only 1 degree from 163 to 164 back to 163, even though the sensor was held in 55 degree open still air. Then he blew shop air across the sensor at 231 seconds till 236 seconds bringing the temp reading back down to 54 degrees. The two steps on the down slope are where the air stream missed the air temp sensor. Conclusions; 1) The GM IAT is capable of reading changes in air temp rather quickly. 2) The GM IAT will heat soak within itself and remain at whatever temp it last saw for quite some time, unless another strong outside influence is presented, i.e. air flow across the sensor itself or heat being transferred through the body of the IAT. 3) Whatever object that is directly in touch with the body of the IAT, (what it is threaded into), definitely has a strong influence on what the IAT reads. Based on what my previously posted datalog shows in regards to the rate of IAT change on the running engine, I am now quite convinced that whatever the IAT is mounted in/on will have an affect on its reading and that reading is not the true temp of the air being ingested into the engine. That would mean that the ECU is not adjusting the AFR in direct correlation to what the actual air temp is, i.e. the fuel correction being applied to the fuel map is not being properly compensated for its density due to temp. The real question is just how important or how much affect this has on the Air Fuel Ratio? Not sure, but it will have some affect and we should at least be aware of that and try to optimize sensor placement in our custom EFI systems based on that.

Yes, it is an open air sensor, not the H2O sensor. What I find interesting is that the IAT installed in the AFM of the factory EFI Z cars will actually read almost instantly any changes in temp. I stuck one in the fridge and it instantly measured the change, removed and again instant changes. I then proceeded to use that sensor for a budget tire pyrometer with my DMM to get and idea of temp differences across the tread, not absolute temps. At any rate, I would like to think the GM open air IAT should also record very quickly any changes to air temp. Might have to play with that a bit to verify it.

If I insulate the headers, yes I agree that would help reduce the heat that the intake absorbs, probably to a great degree. The issue still remains that the intake manifold will still heat soak just from being bolted to the hot cylinder head and the intake and the exhaust flanges are in such close proximity to each other, the intake manifold will still absorb a fair amount of heat which will still alter the IAT readings from what the actual inlet air temp is, (I refer you to the “data log” pictured above). Now this heat soak “issue” that we are talking about is only related to the IAT itself, not the fuel system or the injectors etc. I do feel that based on my findings in having my IAT in the intake manifold like it is, that ceramic coating the intake manifold is a good idea, including the manifold mating surface. Well, as for my “fuel”, I don’t really have any issues with it being a dead end set up. The car starts up great, even after making a hard run, then letting it idle with the hood closed in 100 degree outside temps, i.e. a thorough hot soak of the engine bay, the engine will fire right up, no hiccups etc. I feel that the dead end fuel rail is a simpler installation, visually cleaner, and it functions no different than the flow through design, but this is just my opinion. FWIW, quite a few of the current production cars are using a similar system but they are running dead end from the rear of the car, mine is only dead end from the firewall. I get the impression that you don’t like warm fuel? I would agree that “cool fuel” does help absorb heat from the intake air charge as it is being squirted into the air stream, but there are arguments for preheating the fuel as it will atomize better when it is squirted. As for which way produces the most power or most crisp throttle response? Dunno, I don’t have enough evidence to support it either way other than I feel hot or cold, the engine will run fine. Too hot might affect how well the injectors work and how long their longevity, but that is another issue altogether. Being as it is high pressure EFI, 40 PSI, I have yet to realize any heat related issue regarding my fuel system. Only that my IAT is readings are affected by the fact that my intake manifold is absorbing lots of heat that my Inlet Air Temp sensor is recording even though my actual inlet air temp isn’t that hot, i.e. erroneous IAT readings due to IAT placement in the manifold.

Well, at least one of us isn't...

I’m going out on a limb and try to explain something that I have very limited knowledge in, so if I’m way off base, please set me straight…. The stock rear control arm is quite strong in the loads it is subject to, but in regards to allowing the top of the strut to move for and aft to keep strut shaft stiction down, the lower control arm doesn’t really play any roll in limiting that. It isn’t very strong in that type loading, i.e. it will “twist” pretty easily considering the loads it is subject to. The strut shaft absorbs those loads, just like it does while cornering. With the top of strut unbolted from the car, you can force the strut to move fore and aft by hand causing the control arm to “twist”. Braking and acceleration loads are WAY more intense than the loads our bare hands can exert on the strut causing the control arm to twist. In short, the fore and aft stiction is already present in our Z cars and the design presented above wouldn’t be inducing much, if any more, stiction or strut loading fore and aft than what already exists. Now Double A-arm would eliminate stiction in the "shock" induced for cornering, acceleration, and braking loads…..

Not wanting to thread jack. Grumpy, could we take this discussion to the thread linked below which has more details on possibly using as a low profile super charger manifold. http://forums.hybridz.org/showthread.php?t=115326 Yeah, in looking at this manifold, I would NOT use it on any N/A small block, especially with the current selection in intakes available. The drivers side water passage leading the thermostat is also quite restrictive. What is your opinion of using this intake for a custom low boost roots type super charger, cutting out the middle web and also welding on injector bungs for multi-port EFI? I realize it isn’t ideal, but for a custom “low profile Super charger intake do you think it will work at least “ok” with its huge plenum and its very short 1”-1 ½” long runners? http://forums.hybridz.org/showthread.php?t=115326

Well, we would agree that Bathroom scales are not the best way to perform this sort of test, but as stated in Rons original post, the point of this test was to see how much “DIFFERENCE” in weight there was, not for actual numbers. For the sake of getting as much repeatable accuracy as we could using B-room scales, we placed a long block of aluminum block across the scales and a wooden block between the aluminum and the lower scale to get the aluminum block level. We then weighed one engine then the other. T o verify that he scales were giving figures that were realistic, we even moved one of the engines more to one end of the scales and the total weight was within one pound, i.e. the scales were reading repeatable no matter which end of the aluminum we biased the weight on. This means the footprint” of the weight being subjected on the scales themselves was the same for both engines. As Ron stated, differences in ancillaries and cylinder heads will alter which weighs more than other, but I can’t really see much difference in the heads when comparing aluminum heads. As for 55 lbs difference between comparably equipped long blocks, ie. Aluminum heads, albumin water pumps, alternators light weight gear reduction starters, etc.? I don’t believe it. In tat article “they” said fully dressed but didn’t quality what was included in their term “fully dressed”. Them, “they”….

I wasn’t referring to “fuel” heat soak as in the fuel rail, (I haven’t had any issues wit the dead end fuel rail.) I was referring to heat soaking of the intake manifold itself and that heat soaking affecting the temp of the air going into the engine, not fuel. I like the idea of thermally insulating the IAT from the intake manifold. Good idea.

Sorry guys, but I’m going against the grain on this and here is why, with data logged MAT. The purpose of the IAT is to measure the temp of the incoming air that the engine ingests so the ECU can compensate for air density due to temperature changes, (it doesn’t not take into account air density due to humidity, it takes a Hot wire MAF to do that). I personally feel the intake manifold is NOT the place for the IAT. Mine is in the manifold currently and it heat soaks BIG TIME! The air that reaches the combustion chamber is not the same temp as the intake manifold itself, though the slower the air flow through the intake, the lower the Delta “T” between the air and manifold itself, (Delta “T” is temperature differential), as the temperature of intake manifold will have an influence on the temp of the air that is going into the engine as the air has to pass through that heat soaked intake manifold. Also of note, the temp of the intake manifold will be greatly affected by the amount of air flowing through it. i.e. at idle, not much air flow, it will heat up, but at WOT, lots of air flow to cool off the intake manifold, and vice versa. So yeah, it is a good idea to have the ECU be able to adjust the AFR for what affect the intake manifold has on heating the air entering the engine. In mounting the IAT in the manifold itself, the ECU now is reading mostly the temp of the intake manifold itself, not so much the actual temp of the air the engine is ingesting. I feel that mounting the IAT further upstream would be the best compromise. How much upstream? That will be vehicle dependant and you’ll have to data log that yourself. My best guess for my N/A application, (in boosted applications, you want to measure the temp of the ‘boosted” air so placement will be different, but the same theory still applies), is to install the IAT in my intake tube ahead of the throttle valve, but yet still in the engine bay. I think that would be the best compromise as the IAT will still heat soak, though to a lesser degree and hopefully more consistent to what the actual air temp is going into my cylinders. I still have to get to that before I sell off the intake system and the engine out of the race car. Here is a data log approx 40 seconds in length with my IAT mounted in my intake manifold. Note the temp swings and how those swings follow the throttle position. Top graph is “TP”, aka Throttle Position and “MAT” aka Manifold Air Temp The second graph is just “MAT” only. Note that the MAT max was 144 degrees, min was 99 degrees. Also, you can see the temp drop steadily while the throttle was WOT. The IAT sensor was registering “HEAT SOAK” and then would cool down gradually while at WOT. This particular data log is 1st gear, 2nd gear, 3rd gear WOT blast, then a quick 5th shift for a brief part throttle cruise! I do agree that intake manifold heat soak does affect the air density of the air the engine is breathing, but not to the degree my IAT was registering.

We didn’t dyno the car, the V-8 project came up before we got to that point, though it does run strong. The throttle body is a Nissan 60mm that I carved on so it would visually match the N-42 intake externally, also port matched the N-42 manifold for the 60mm, flipped the TB upside down and actuated it via a Teflon lined braided stainless throttle cable which will all be sold with the intake. I do feel that for a race application, the OE EFI intake manifolds don’t allow the engine to run to its true potential. An ITB/IR set up would yield MUCH better upper end power than the OE manifolds.

Olie, you've got mail, regarding the intake pipe...

I realize this I not related to your custom intake, but I do happen to have a pretty rare IR/ITB Fuel Injection L-6 intake that I’m putting up for sale in the next week or so. It is an ITB Mechanical Fuel Injection manifold with the mechanical injector nozzles still installed. My plans were to either graft on bosses for O-ring style EFI injectors, or use the intake flange from an OE EFI intake and modify it in such away to allow this intake to be “bolted” to it without having to modify this ITB intake, (it seems like such a shame to modify this rare and cool intake). Any how, this intake as well as the custom N-42 EFI intake pictured that is machined for O-ring injectors , (currently has C-4 Corvette 21 lb/hr pencil beam injectors controlled by MSnS-E isntalled), is currently on our race car and running, is up for sale. If you are interested, E-mail me for more details and pics at; braapZ350@hotmail.com

It has been our experience that when the damper fails on an L-6, the L-series crank will “spider crack” at the main and rod journal radiuses. When I mean fail, I mean the inertia ring has physically separated from the hub itself. Your picture is hard to make out so it’s hard to say if the inertia ring has actually “spun” on/around the damper or if the rubber is just starting to separate externally, (hopefully it is just starting to separate so no damage has been done to the crank itself…). If the inertia ring has actually spun, then there is good chance the crankshaft is no longer any good, i.e. junk. I know that is NOT what you want to hear and I can’t think of any other way to sugar coat this, but if the engine was driven for any length of time or under hard loads with a separated damper, chances are the crank is cracked and could fail. If it is indeed cracked, (only a magnaflux will show those hair line spider cracks), the crank could last for quite some time before it actually fails, of course that is dependant on how it is driven… Hopefully you caught this in time…. Paul

Rusch Motorsports would be glad to sponsor another HYBRID-Z PINKS project, such as another custom cylinder head like we did for the original PINKS project, especially it were to remain L-6 or even RB powered. BTW, we haven’t heard from the winner of the PINKS long block… Does he have it up and running? Awaiting to hear just how fast that combo is running once truly “dialed” in….. Paul

In Garretts thread, I gave a little advice on core plugs. I only touched the surface last time, this time, lets get a little deeper into the meat of what is going on and why, and as an added bonus, I’ll show how to properly install core plugs! I’m sure my opinion posted here will conjure criticism, and as I’ve posted before, if I’m wrong in what I post, I encourage those in the know to make it known so that others won’t be misguided by misinformation posted by myself, or anyone else for that matter. First off, if your core plugs are popping out in a ”boosted” application, especially if they only pop out at “other than race” conditions, i.e. engine isn’t warmed up fully yet, etc. my honest opinion is that your head gasket is releasing combustion pressure, for one reason or another, into the block while the thermostat is mostly closed if not fully closed, and that is why you are blowing out core plugs instead of popping radiator hoses, radiator caps etc. Case in point…. This core plug ”pop out issue” doesn’t seem to happen when at the drags, or under heavy use conditions such as on the freeway or running down the strip at full boost, i.e. your thermostat is most likely open as the engine is fully warm. In the case of 280Zforce, he just left the school parking lot, i.e. his engine was ”cold” and his thermostat was most likely mostly closed, if not fully closed. As a fix, there has been reference in the past to shooting screws through the core plugs themselves and/or covering the core plugs with straps, etc to keep them in place. I ask is that really smart? Do you see where I’m going with this? It is in my best opinion that if you screw your core plugs to the block or cover them with straps, you are doing nothing more than adding a band aid to a broken arm. Sure, it stops the bleeding, but it doesn’t FIX the REAL problem at hand. I don’t think it could be “block flex”. If the block was flexing enough to allow core plugs to release, then the crankshaft would’ve seized up in the main bearings way sooner as it wont tolerate THAT much block flex. If your engine is popping out core plugs, there is DEFINITELY something causing this to happen. I personally feel that it could be at least mild if not moderate detonation ”lifting” the head off the block due to excess cylinder pressures, i.e detonation. The L-series has been documented on this forum with detonation issues to some level or another, even N/A. At any rate, “whatever” issue that needs addressing that is causing the core plugs to “pop out”, first needs to be dealt with. After the ”issue” is dealt with, then lets install your core plugs properly without having to WELD them in. If you don’t address WHAT is causing your core plugs to pop out in the first place, screwing them, epoxy-ing them, strapping them, etc, will do nothing more than show you the next weakest link in your engine at some point in the future. That could very well be the pistons, head, block, rods, etc. Think of the core plugs popping out as your ”little red flag” waiving, telling you that you have some other big issue that needs your immediate attention such as “detonation”, blown head gasket, etc. Ok, now on to properly installing core plugs in your L-series block, even full blown hard care high boost applications. If they “poop” out after this, then you have other issues such as detonation to some degree, that needs dealing with. I truly believe that you should leave your core plugs installed withOUT screws or straps because when they pop out they are screaming at you that you have other issues that need to be addressed or it can/will cost you MUCH more next time this issue rears its ugly head, ie. broken engine, instead of popped out core plugs…. When you install your new core plugs, be sure that the core plug hole is cleaned. I use a sanding wrap on my die grinder for EVERY engine build that Rusch Motorsports does. I then apply a liberal coat of “Permatex part 1A form-a-gasket” to the core plug hole in the block AND around the perimeter of the core plug itself. I then tap in the core plug in with a socket that fits the core plug nicely. What I mean by “nicely” is the socket fits loosely, not snuggly. You don’t want the “core plug” to collapse around the socket and capture it as you drive it in. Tap in the edge of the core plug is just below the chamfer in the block, wipe off any excess sealant, let stand for at least 24 hours before adding coolant/water. I also agree in not using Silicone as the sealant as it doesn’t really offer any “holding” power. For those who want a little more holding power for “whatever” reason, JB weld can be substituted in place of the “Permatex part 1A”. Just remember that when you rebuild this engine in the future, you should “tip” your machinist/engine builder generously for having to deal with those JB welded core plugs…As an aside, machine shops have been known to fire customers for various reasons…. First picture shows a core plug hole with the core plug just removed from Rons F-54 block… Second picture shows that same core plug hole after being dressed with a sanding wrap. Third picture shows that same core plug hole and the “as packaged” Permatex Part 1A” that we use. Hope this helps…. Paul Ruschman

The Thermostat is a restriction to flow within the cooling system on the outlet side of the block, (especially when the engine is cold and the thermostat is mostly closed, if not completely closed), and with the water pump pumping water “into” the block, that is a restriction on the inlet side of the block. SO, if the head gasket was to release a small bit of combustion pressure to the cooling system, (i.e. into the block itself), Technically, that high pressure could very well be contained within the block itself due to the restriction that the thermostat and water pump present, (especially when the engine is cold and the thermostat is mostly closed), and there fore pop out “core” plugs, and not blow off radiator hoses, etc.

Too late, I already read it and as you may have guessed, I about came out of my skin… NO NO NO!!!!!! They are NOT FREEZE PLUGS!!! They are CORE plugs… Engine builders/machinist prefer to call those “core plugs” or “soft plugs”, the term “freeze plugs” is a misnomer. Those plugs have absolutely “NOTHING” to do with protecting the block from cracking, and I repeat, “NOTHING” to do with protecting the block from cracking due to the coolant/water freezing etc. those holes in the block are there to allow the sand to be removed when the block was originally cast, i.e. “core holes” so the plugs that fill those holes are called “core plugs”. Back in the early years of the automobile, if a block froze with the old style core plugs, those plugs would sometimes pop out, so most people started to believe that was what those plugs were for, to relieve the pressure of the expanding ice. They were dead wrong. Their blocks and heads still broke and cracked if they froze even though the Core plugs popped out, (I’m sure many of you have experienced this on your own), but somehow, that term “freeze plug” stuck around. Now, punishment for not reading my post in Garrets thread about popping “CORE” plugs”, I want you to come to the board and write “core plug” 250 times….. LOL Ok, Ill get down off my sop box now…

Yeeup... and Yeup. Oh, and Yeup. If you CAN keep the PCV, please do. Your engine will thank you for it in the long run. The function of PCV helps in soo many ways, yet takes noting anyway in the way of performance. In fact, it can be argued that the PCV will help KEEP performance for the reasons listed above. Your bearings and rings will last longer, your oil will remain cleaner between oil changes etc. Keep it if you have the choice. Just my $.02

I apologize. Tony is absolutely correct. In my readings about that water passage on EFI Throttle valves, I interpreted the water passage to be emissions related for temp consistency and as such I have always struggled with that theory for the same reasons Tony mentioned, i.e. there really isn’t squat for contact area for water to transfer its heat into the throttle valve to be effective in that capacity. Any how, thanks for setting me straight on that.

Olie, I really hate to say this. MSD has great products, “when it works”. The fact of the matter is that the MSD ignition components have a failure rate that is, in my opinion, unacceptable. How many write ups here on HybridZ and elsewhere have you read regarding an MSD failure? We’ve seen it watching a PINKS episode where someone had an MSD box failure mid race. As much as I hate to say it, it is for the reliability reason that we will not carry or endorse MSD products. If MSD was to make an effort to get their failure rates lower than they currently are, we would be more than glad to personally run and endorse their products as they DO work. We prefer to use ignition parts that we can trust, not constantly be second guessing. There is no debate whether MSD ignition components are up the task of igniting some of the most demanding and grueling combustion chambers out there. The debate is how long they will last! If we all knew what the “ideal conditions” we need to meet to keep the MSD boxes alive for an acceptable period of time, then we would sell MSD with the FIX kit to keep it alive. Till then, it’s J&S, Mallory, (Jacobs USED to be on our good list till they sold out and are now made across the border, Quality assurance has gone to CRAP ever since). Good luck, Paul Paul Ruschman