Zmanco

I'm running KnockSense with the 81-83 ZXT knock sensor. Just a thought: it might be simpler to source one of those.

A healthy battery should be able to restart the engine after running alone on battery for 10-15 minutes. So either the alternator isn't fully charging the battery, or the battery is at the end of its life.

Today I ordered the Blue/HT10 combination. I figure I'm eventually going to land up with dedicated track pads so may as well go there now.

Just curious if anyone has any evidence that the holes in air dams with "brake ducts" actually have a significant effect on brake cooling when used without adding a hose to route the air to the brakes? My sense is that very little of the air flowing through the duct hole actually reaches the brakes. I used to have the old style BRE spook with brake ducts without any hose and one track day I put some sheet metal across the duct holes and didn't notice any difference in braking - brakes didn't fade with or without the ducts open. However, that was when I was running NA and I didn't measure brake temps so don't know if the temps were just elevated yet still within what the system could tolerate. I'll guess that adding ducting hose to route the air to the brakes would make a difference, but I'm curious if anyone has any evidence that the holes in the air dam make a difference without adding the hose.

I spoke with one of the techs at Hawk and he recommended the HT10 for the front, and Blue for the rear (Blacks aren't available for these calipers). I asked what he thought of a more street friendly setup using HP+ front and Black rear and he said it should work, but that he was concerned the HP+ might be a bit grabby at temp and also that the Blacks were hard on the rotors compared to a typical street pad. I hate the StopTech pads I currently have on the car, even for street use, so may take one more stab at a single set of pads for street and track by trying the HP+/Black combination. At least that's the direction I'm leaning right now.

Setup: 73 240Z with turbo L28 Front: Toyota 4x4 calipers with 300ZX vented rotors Rear: 240SX calipers with 300ZX solid rotors Adjustable proportioning valve Top speed ~130 mph at the end of the straight with braking to ~70 mph before turn-in. Does anyone have information that shows how the various Hawk materials behave over temp? It's time for me to order track pads and I need a higher coefficient of friction for the rears, otherwise they don't do enough of the work. I've found this page attached that describes the materials in vague non-quantitative terms. It appears to me that if I went with Black front and Blue rear I'd be headed in the right direction. But I'm at a loss to tell how the Blue and HT-10 materials differ. For example, should I use HT-10 instead of Blue in the rear? An alternative is to use Porterfields R4E up front and R4 in rear. The R4E has a lower coefficient of friction than the R4, but not by that much - see attached. I'm worried that even with the rear proportioning valve all the way open, there still won't be enough rear brake bias. Suggestions? hawkracecomp2009_02_05_03_15_28.pdf portrace2008_11_06_02_41_04.pdf

Under normal conditions, what does the ammeter read? If the fuel pump is powered from the battery instead of alternator, that would explain the higher reading under increased load. That means you should see around +10A under normal conditions. Is that what you see?

300 whp from an L24 without any headwork using a stock cam (and I'm assuming pump gas) seems optimistic. What will you be using for engine management?

This is inconsistent with being due solely to warm fuel. The pump is likely to pull less current when it cavitates. Even if it pulls more current, you should not be seeing that as in increase in ammeter readout. The ammeter only displays the net current going into or out of the battery. It does not measure how much current is pulled by the other devices in the electrical system. Not saying that warm fuel isn't part of the issue, just that you probably have something else going on as well with your electrical system.

Bartman, as we were discussing in another thread, I have a similar situation. What was the outcome of this second version of your ducting? And what did you finally settle on for a solution?

I have a thick intercooler as well and remember Bartman's posts in this thread: link I need to revisit that...

http://www.thezstore.../PCLC04/16-7017

Choice of radiator matters, no doubt. But I'm finding that ducting and fan have a larger influence. I recently put the mechanical fan back on for a while with the new MSA cross flow radiator I installed, but without a shroud, and found that even in 95F+ weather the water temps often went below 180F. However, without a shroud the mechanical fan does not move enough air to keep the engine cool at idle, so I recently made a custom shroud and put the biggest SPAL fan (14") that would fit. Cooling at idle is now excellent, but I see engine temps running in the 185-190 range at highway speeds on hot days even with the efan running. Good as the SPAL fan is, the mechanical fan moves more air once the engine is above 2k rpm. My conclusion is that the airflow on a 240Z, even with spook, is so poor that the fan is making a significant contribution even at 75 mph. There is a lot of discussion about adding ducting to improve airflow into the radiator, but with a large oil cooler and turbo intercooler, I haven't yet figured out how to add ducting without removing the stock grill, something that I really don't want to do. Lastly, the primary benefit of a cross flow radiator appears to be for applications where the shape is rectangular i.e. rather wide and not too tall. It turns out that the MSA crossflow end tanks are wide enough that the remaining core is nearly square. Hence I think for our early Zs, cross flow by itself probably makes little difference.

I'm not trying to lecture about how to drive on the street, just going to point out that if something unexpected were to happen at high speeds, I'd want to have a tire with more grip and predictable breakaway to help me get things back under control - not a higher treadwear number. I second the Direzza recommendation. I'm on my second set (which is the first time I've ever bought the same tire again) and about to buy a third. They have reasonable endurance for the street and do better than most of their peers at not getting greasy as the track warms up. Their steering feel is excellent (compared to the Yokohama ES100 and Kumho MX I've also tried) and they break away predictably. I'm seeing 6-8k miles and 3-4 track days per set. What they don't do well is deal with heavy rain, or sub 50F temps. At this time, they are the best tire I've found for both track and dry street use. Edit: Tire Rack has a $80 rebate for the Direzza thru the end of July. Pretty much pays for shipping.

I used the mounts from the 73.

Ideally you will have already decided on your power target which will give you the airflow required. From there you can decide how much of a pressure drop you can accept across the intercooler and piping and still run within an acceptable range for the turbo you have selected. For me, my goal was 325 whp and I was borderline 2 vs. 2.25" pipe. I probably could have gone 2" and if I was to do it again, I would. Answer probably depends on a variety of things. For example, is it only street driven with occasional short bursts of WOT? Then a properly maintained stock system should suffice. If you're looking at road courses with 20+ min sessions in the summer, then probably not. Keeping the temps reasonable in traffic with AC on requires a lot of airflow over the radiator. On my 73 when it was stock with the dealer AC, the stock fan and radiator could not keep the engine cool in stop/start traffic on 90 F days with the AC on. But there are people with 280zs and factory AC who get cold air at idle and don't overheat. Not sure what the difference was as I gave up working on it and eventually pulled the AC off the car. But I live in Colorado where it's not as hot and definitely not as humid.

Keep in mind that each squirt costs an injector opening time which is typically 1.25 ms. At 6 squirts that's an extra 5 opening times or 6.25 ms. At 6k rpm there is 20ms total per combustion cycle. Make sure there is enough injector duty cycle left at WOT.

Thought this was relevant to this thread so I'll add it here - hope it's not too much of a thread jack: Last night I installed an MSA cross flow radiator and the shape of the core is such that my 2 12" fans won't fit. So I decided to go back to the mechanical fan at least until I find an efan solution. As cgsheen said, I was able to route the intercooler pipe behind the fan. However, it just barely clears and I also had to notch each fan blade to clear one of the mounting bolts for the sensor for the 36-1 EDIS wheel on the damper. Car is a 73 and intercooler pipe is 2.25". 2" would give much better margins for clearance. 2.5" probably wouldn't fit without occasional rubs. The notches are a hack job - I just used a box cutter to get it done to see how well it cooled. If I stay with this, I'll go back and do it right with another fan. And please disregard the tacky purple/black BOV. It came with the pipe kit for essentially no extra cost so I just installed it to get the engine up and running. Turns out it works so well that I just can't justify spending money to replace it with a brand name. Black spray paint labeled as "high temp" wasn't.

I had an N42 head that had a casting defect just outside the base of the spring seat on an inner cylinder. I had run the head for quite some time and it only showed up when it began to leak coolant into the oil. I found it by pressure testing - would probably never have found it by sight. I can't tell you if it's something to be concerned about - in my case I had another head so reassembled everything on it and used the first head to practice unshrouding valves.

When I looked down into the bore, I only saw a small hole at the bottom edge where oil entered. I didn't see any other passages, but I didn't check every one, and wasn't looking for a second hole either. Maybe someone who has a head disassembled can take a closer look? In any event, the time-sert is shorter than the threads on the mechanical lifter so I threaded them all the way to the top and then screwed them into the head. Use this approach and the time-sert will not go down far enough to block the oil port.

Macambra, I have 2 extra if you need them. Paypal $5 for shipping to me daniel at bailin dot org along with your address and I'll send them out.

It's hard on the 240Z to route the intercooler piping and not interfere with the mechanical fan, hence most go with efans.

I'm only interested in the front for now (don't have any adjustable parts on the rear) so will drive it up on ramps for the front and lift the rear with a jack to level it. The front has TTT LCA and TC rods so no need to unload the suspension to adjust camber and caster. We'll see how it goes - I'm sure it won't be as simple as I'm imagining.

With the hydraulic lifters replaced by mechanical lifters, why would you want oil to flow into the bottom of the lifter bores?

Just saw this thread and I had the exact same issue running MS2/Extra and a Blaster II coil on the track. I could not replicate it on the street. I dataloged and found it was going completely lean when the power fell off - which can mean there is no spark. I narrowed it down to either the transistor/driver in MS or the coil overheating. I figured I was eventually going to go EDIS anyway so used this as the reason do it. I haven't had an issue since.