Nigel

I just recently did some testing with an Aeromotive FPR mounted in two different locations. Both were after the rail, so this doesn't directly relate to issue at hand, but the results were very interesting never the less. I found that the distance of the FPR from the fuel rail makes a dramatic difference to fuel flow and pressure in the rail, and I would have to conclude that the ideal location is as close to the rail as possible. In fact, I mounted my FPR directly to the end of the rail. I have datalogs of my air/fuel ratios with the stock ZX regulator, and the Aeromotive FPR attached to the passenger side inner fender and to the end of the fuel rail. You can clearly see the impact on A/F ratios compared with the location of the FPR. As soon as I have some time, I'll do a write up with greater detail, and provide some screen shots of my datalogs. As for mounting the regulator before the rail, I too would be concerned about heat soak. Nigel '73 240ZT

The Haynes manual I have (covers 240Z to 280Z) also indicates that the brake system was the same on all 240's. But obviously , that's not the case (to '73 240Z owners at least). There are also differences in the wiring, which are not reflected in that manual either. I just want everybody to be aware of this, so that '73 Z owners don't get led astray Nigel '73 240ZT

I'm confused... There was no 280ZX Turbo in '79 and '80. The Turbo model was introduced in '81. And as far as I know, there is only one version of the 280ZX Turbo CV axles, and they were only available from '81 to '83. Nigel '73 240ZT

Hey Scott! I think the throttle position switch will tell the ECU to dump in more fuel at full throttle. Have you confirmed that the switch is operating at the correct throttle positions? A brief spike to 14:1 doesn't sound too bad though for the big gulp of air it's taking in, so long as it's not hesitating. But I don't know what's normal for the Z31's. Nigel '73 240ZT

My base FP is set at 40psi. I can raise it up a couple more psi, but I think all that will do is result in my having to offset all my RPM fuel values down. I’m aware of the accelerator pump feature, but to the best of my knowledge, that’s just a brief extra shot of fuel lasting for only about a second. And indeed my AFR’s drop when I floor the throttle. The issue is that they start to climb back up as boost increases then drop once peak boost is reached. It seems that the demand for fuel is not increasing in proportion to the increase in boost. Here’s the theory behind my tuning: At maximum boost, the MAP FUEL values are pretty much constant as that boost level is held pretty much to redline. So, achieving my desired AFR should be done through RPM FUEL values. And I’ve managed to get very consistent AFR’s based on that. Now, the rpm range while building boost is around 1200 to 1500 rpm (in otherwords, it takes 1200 to 1500 rpm to go from 0psi to ~9-10psi) with peak boost arriving around 3750 rpm. My theory is that if RPM FUEL values in that range are fairly close together, and are not that far off the peak RPM FUEL values, then achieving my desired AFR should be done through MAP FUEL values. Just out of curiosity, how many people have watched their AFR’s while building boost?

Stats: L28 Turbo, T3TO4b, SDS EM3-6F, RX-7 440cc injectors, Walbro 255lph pump, ScottieGNZ down pipe, 3 in mandrel exhaust, Techedge DIY WideBand O2, ~9psi boost... Earlier this year, I set up the Techedge to datalog 02, RPM, MAP, Throttle Position, and Air Temp. Last week, I installed an Aeromotive adj. FPR, and I'm now in the process of retuning, because the stock regulator was obviously too restrictive. I discovered something interesting when looking at the AFR with the new regulator. I hope to post some screen shots soon, but in the mean time, here's a description of what I'm seeing... What I'm doing is logging a run in 3rd gear, full throttle from around 2500 rpm to 6000 rpm. Boost builds in a linear fashion, and I reach peak boost around 3750rpm. After I installed the new regulator, when I stomp on the gas, the AFR would dip to < 13:1 then started to rise in step in boost up to around 14.5:1. Just as I reached peak boost, they droped down to 12 - 12.5:1. But my RPM FUEL values are fairly close together around the RPM range this occurs, and my MAP values were rising at a constant slope. I had to dramitically increase the slope of the MAP FUEL curve as soon as I started to make boost, and then level them off as I approached peak boost (Since the peak boost MAP value is fine). So, for example, my MAP fuel value at 5 psi is nearly as much as my value at 9psi. Even then, I still haven't been able to get AFR's to go below 13:1 until I reach peak boost. In other words, it's looking like I need as much as or more fuel while building boost, then while actually maintaining peak boost. Does this make sense? Nigel '73 240ZT

Several years back, I met a guy at one of our club meeting who stuffed an L28 (don't remember if it was turbo or not) and 280ZX driveline and suspension into a Hyundai!!! Talk about a sleeper... Nigel '73 240ZT

If the problem occurs when the fan is turning off, then I'll bet it's caused by the spike from the relay coil. Try connecting a diode across the coil with the cathode (end of the diode with the stripe) connected to the positive side of the coil. Does the ECU switch the coil to ground (sink current) or does it supply 12V and the coil is always grounded (source current)? Unfortunately, I don't know what would be causing the ECU to run in open-loop mode... Nigel '73 240ZT

So, did rewiring the fan help? If that didn't do it, what happens when you switch the high speed fan with a mechanical switch like you are doing for the low speed fan? Your problem could be related to the wiring of the relay coil to the ECU... (what is an EST Monitor Error anyway?). Relay coils (and solenoids) can cause all sorts of problems for electronic circuits. They typicaly cause voltage spikes when they are shut off. However, you say you are having problems when the fan is turned on. So, it may have nothing to do with this. How do you have the coil side of the relay wired? Just as a side note, I recently blew the rad fan controller transistor in my SDS ECU. I had the fan relay coil powered by branch circuit off of the main feed line to the fan. The ECU transistor grounds the coil to turn the relay on and off. Something caused the main fan power supply fuse to blow and the surge from the motor coil fed back through the ECU since it was on the same circuit, frying the transistor. I now have the relay coil powered by a circuit completely separate from the fan circuit. Oh yeah, 10 AWG is typically good to around 30A. Aren't those fans rated at something like 40+ amps? Nigel '73 240ZT

I had a Magnaflow high-flow cat installed when I had my 3" exhaust done on my '73 240Z Turbo. I think it was well worth it. It's like driving a modern verhicle now. I don't even have the back of the car sealed up 100%. High-flow cats are cheap now days, they have minimal effect on engine power, and I've never had any issues with the floor heating up. So, for not much of a downside, I was able to make my Z more enviromentaly friendly. However, if you car isn't tuned very well and is dumping out a lot of crap, a cat isn't the correct solution. Nigel '73 240ZT

The bung that was included with my Autometer Comp probe was stainless steel. What leads you to believe yours is aluminum? I had mine welded to the manifold with a mig welder using standard steel wire. Then, the probe was screwed into that using the supplied compression fitting. The one in J. Soileau's picture looks like the "street" probe which, I believe only comes with a screw in NPT fitting for the manifold, and no weld-on bung. Nigel '73 240ZT

Hey Scott! That can't be possible with a manual transmission. The engine is mechanically linked to the wheels, so there's no way. In an automatic, I could see it happening because of the torque converter. Either something else has changed, or you're not remembering the RPM's properly. Use this transmission calculator to find out what the correct speed to rpm should be... http://www.geocities.com/z_design_studio/ Cheers! Nigel

I have Z31 Turbo CV Axles in my Z with the 260Z rear bar, and everything clears just fine for me... Nigel '73 240ZT

I have a rear bar from a 260Z in my '73 240Z. It bolted in perfectly, using the pre-existing frame mounts. I originally bought a 280Z bar, but the arms are too long. I would have had to cut off the mounts and weld them back on further forward on the car. Nigel '73 240ZT

I like it. The back is a bit too Vett like though, but otherwise, it's quite unique with just a hint of Camero in the grill to remind you of what it is. The problem with a "retro" look is that before too long, everyone looses interest and then where do you go stylistically? Nigel '73 240ZT

28" Rims! Anyone want to guess the weight? Tires are $30,000!!!!!!!!! Nigel '73 240ZT

The 15/16 MC isn't quite a direct bolt on for early Z's like those instructions imply. Prior to 1973, the brake lines to the MC are reversed compared with the later models. You will have to rebend/make new brake lines for the connection to the MC if you have a '70 to '72 Z. Nigel '73 240ZT

I put mine in the manifold just before the turbo flange. I had a bung that came with the probe welded to the manifold. But if just taping the manifold works ok, then obviously that's easier. As for which probe to get, the cheaper the probe, the slower the response time. I went with the mid priced autometer probe (the "Competition" version). Wideband is definitely the way to go, but it helps to have a backup reference. Nigel '73 240ZT

I can't help but wonder if that's supposed to be 1950 CFM, not 2950. That would make more sense as the the 18" model is rated at only 2500 CFM! When I was researching my fan options, I saw some outrageous claims. For example, there is an electrical fan company called Zirgo that makes S blade style fans like Flex-a-lite. Derale, and others. According to the Zirgo datasheet, the Zirgo ZFU16S 16" s-blade fan puts out 3630 CFM at only 10A! http://www.zirgo.com/files/ZFU16S.pdf If you look closely, they also give an input wattage rating of 250W. That calculates out to 19A which is almost twice the current rating they give! I e-mailed Zirgo about this and they admitted that the current rating is wrong, but it's been six months and they still haven't corrected their literature. They ignored my questions about their super high CFM ratings. In fact, they have one 16" fan that's rated at 3950 CFM but only draws 7.5A! I contacted Flex-a-lite as well, and an engineer there replied to me and said that he had tested a Zirgo fan and didn't get anywhere near the flow that Zirgo claimed. From what I've seen, the Flex-a-lite model 398 is currently the most powerful 16" S-blade fan available on the market at 2500 CFM's at 17A, and that's what I chose. http://www.flex-a-lite.com/auto/html/syclone.html So, be very weary of the CFM and current ratings for electric fans. The best thing to do is to compare the ratings for similar styles of fans from different companies, and be suspicious of any claims that are way outside of the average. Nigel '73 240ZT

No, no offence taken at all! I was just kidding around. Hence the little smiley face at the end. Please don't take offence at this question, but what's up with the first letter of every word being capitalized? I've never seen anybody type like that before... just curious. Nigel '73 240ZT

Here in Canada there are 2 types of insurance policies for cars, 19 and 19A. Most people and many insurance companies aren't even aware of the the 19A option. With the 19A policy, your vehicle is covered for a predetermined replacement value. So, for example, my Z was appraised for X thousands of dollars. If my Z were written off or stolen, I would be covered for that full amount and not some arbitrary number the agent pulled out of thin air. Is there no similar option in the States? Like I said, many insurance companies here have never even heard of this, so you may have to phone around. Nigel '73 240ZT

It depends on the BOV and the fuel system. Non-recirculating BOV's are designed (or are adjustable) so that they only open when the manifold vacuum is greater than idle vacuum. That way, they won't suck in (or possilbly blow out) unmetered air under normal operating conditions. Other BOV's open at manifold vaccums less than idle. In fact, some open at as little as 5in of vacuum. I have a DSM BOV, and it cracks open around 15in of vacuum. On a stock ZXT, this would be a problem if the BOV was not plumbed back into the intake after the air flow meter, because the air flow meter wouldn't see the air introduced by the BOV. Most aftermarket fuel systems (and many factory systems) use a manifold air pressure sensor and they don't really care about anything that happens before the throttle body. So you could use a BOV that opens at less than idle vacuum. However, this would introduce an unfiltered air source. Nigel '73 240ZT

Hmmm... well, I've got a used VDO oil temp gauge from a VW that a friend gave me for free. Will that still count?

I have a recored, high density fin, ZXT rad, 16" Flex-a-lite Syclone 2500CFM fan, and an RX-7 oil cooler. My coolant temps have never gone above 185 degs even when hot lapping in 90 deg weather. I'll bet the RX-7 oil cooler helps this a lot. I highly recommend them. They're huge, but they have a built in thermostat so they don't over-cool the oil. I got my used for $100CDN. Sorry, but I don't know the year. I'm putting an oil temp gauge in this weekend to see what oil temp I am running at. Nigel '73 240ZT