Dat73z

I would start by reading the plugs and inspecting the oil to ensure it isn't a malfunctioning carb issue dumping fuel into the engine, although if that was the case I'd think you would've already fouled out the plugs and have a crankcase full of fuel. I'm not sure what benefit you'd get from the fuel flow gauge, I'd think an afr gauge would be more useful. For what it's worth on a LS1 GTO I think I was averaging like 6-8mpg mostly hooning around town. Never had a carb'd big block but 2-3 might be reasonable?

So I have noticed some tiny dots of what looks like oil on my hot side charge pipe over the past few weeks. It's fairly minor but has been driving me nuts as everything in front and around it is bone dry. Not sure if it's being slung from somewhere else, maybe the crank area and my efans are blowing things around.

@rossman With the cooler weather I have noticed the afr gauge is generally reading a half a pt or so higher across the board going from 90-107F weather which is when I was doing the majority of the jetting to recently dropping into the 50-60s in the AM. The turbo does like the cooler fall weather though, and humidity here is low. I've only lived with EFI turbo cars in the past so this is all new to me. I should probably carry extra jets with me for cool/hot, and high vs sea level elevation lol.

Pulled the plugs again to check and fine tune the mixtures a bit more. Things are looking pretty close to where I had it tuned before machining the mixture screws for orings, but I've noticed the tune changing slightly with the cooler fall weather.

Quick weekend update. Life has been busy but I managed to put another ~hundred miles on the car. I've been trying to drive it for all of the errands to get more shakedown time in. I've noticed the boost response and over boost values are fairly sensitive at certain ranges. Fundamentally I think I'm basically tuning the duty cycle of the boost control solenoid to match my setup. So I'll keep playing with the settings. I'm hoping this AM I can make a trip to Home Depot/Harbor Freight and at least pick up the parts to build the boost leak tester.

After going hard at work for a few months I felt like I was burning out so I decided to take this afternoon off. During my grocery run I was playing with the EVC-S a bit more. One pull felt exceptionally stronger than the rest. Looking at the peak hold function, boost spiked to 16.5psi. So I think I need to tune things out a bit more. Each pull was smooth to 6-7k, no detonation that I could tell at least and AFR's were within 11-12.

Finally almost at the weekend. Got word that my needle and seats are ready, but this weekend is my wife's birthday so we'll see if I can make any progress with the turbo build. If I can find an hour or two, I would like to build a simple tester to boost leak check my system. Also one thing I found interesting: I took the car out to grab a quick lunch yesterday and noticed even with the EVC-S set to wastegate mode I was seeing 10psi, which is my wastegate spring pressure. I thought I had saw a 2psi drop past the butterflies from system losses where my gauge is reading before boost control. So I'm not sure if I'm misremembering, but I guess this is what happens when it takes me months to do some simple boost adjustments. I'm going to start writing things down in a log book and keep it in the car.

@Zetsaz I spent a few weeks investigating the gaps a couple years ago and the conclusion I came to was every 70-73 240z I saw in person (didn't check the 280s) was assembled differently from the factory. My car has maybe a mm difference between the DS and PS rockers, add to that the tolerances of a mm here and here for how the seams in the doors were folded, fenders, etc. and you ended up with a couple mm differences here and there lol Best way to resolve this is probably to line up the rears of the doors first, then add or remove metal to get nice even gaps before paint

I took some measurements on my doors which don't look like they've ever been taken off the car, but my fenders have been shifted around. Also, the way my rockers were welded from the factory are different DS versus PS. The gaps measure 4-7mm, so somewhere between 5-6mm sounds about right.

Did some testing tonight and the HKS boost controller holds consistent boost. With the MBC I was getting random spikes, and sometimes inconsistent peak boost. I really need to check for boost leaks. At WG spring pressure only I was seeing 10psi on the HKS controller. At 25% offset I was expecting to see somewhere around 12psi but I only peaked at 11.2 psi. The solenoid position also seems ok, the valve body is cool enough to touch. But of course at shutdown unless I open the hood everything heat soaks.

Some initial settings to start: Low Boost A Offset: 10% Response Value: 10% Over Boost Value: 3PSI Warning Value: 11PSI Drop Value: 100% In doing some research, the Overboost Value and Response Value for these controllers is critical to get right. Or you get hysteresis in the controls like you see in the chart and can overshoot on boost, will hit the warning but won't drop boost to gate default, or have other issues. It's been many years since I've done control work/design so I'm just going to play with the settings at low boost until I get a good feel for what the settings are doing, and what the turbo likes.

Last night I was able to tidy up the wiring and input some base values into the boost controller. Some tuning notes: Since I'm blowing through carbs, the onset and response of the turbo seems fairly critical. Depending on how the turbo spools, throttle position, load and rpms in the dynamic range afrs will be affected. This is why if I gradually roll into the boost at a higher gear I can hold the afrs flat at 11.5 from 2.5k rpms to redline. If I punch it, with a reasonable pump shot that isn't crazy for other conditions I could see 13afrs at 3k before the mains tip in. I read online somewhere some Supra guys like to have the afrs go slightly lean at boost onset to help the turbo spool. I'm not sure about that so I've just been tuning for 11-12 afrs across the board. There's also the affect of the pump jet size pulling in at higher engine demand. And you can also mask some of these issues by tuning richer but that affects street drivability in other ways, like transitional rich bogs and fouled plugs. Probably too much information for this post, but after work today I'm going to start street tuning the turbo response. I can alter offset, overboost and response with my evc-s controller. I can't tune boost by gear with this setup which would be more ideal, but hopefully I can alter the response over the standard wastegate performance to achieve a better result across more dynamic non-WOT driving conditions (e.g. down low and at the transition for streetability). Also hopefully this will be better than my old turbo XS controller which was definitely spiking here and there which just made things go momentarily rich as the float bowls got extra pressure. I put it back in storage, maybe I'll bring it back out for another project in another decade or two lol

Tonight I finished installing the boost controller. I ended up mounting the solenoid where the throttle bellcrank used to be. If it's too hot in that location I'll move it. If I get a few minutes this evening, I want to tidy up the wiring behind the dash a bit. I've added a few things since I reloomed the harness after the swap, so it'll be good to organize some of the runs.

Spent a few minutes this evening and looked for suitable locations for the MAP sensor and boost control solenoid. I think it would be pretty cool if I could mount the solenoid where the throttle linkage used to be. Unfortunately that area is at the firewall about a foot from the exhaust. So it's looking like by the washer reservoir is probably the best spot.

This afternoon my boost controller came in so I temporarily stuck it under the radio to see how it would look. I'm still undecided to either hide it or have it exposed. I guess at this point my car has become a restomod so maybe having it easily accesible is the way to go.

This evening I was curious and checked the plugs. It seems I got the BR8ES hot enough today to at least start self cleaning. The porcelain was all black after my mountain run on Fri. This week I'm fairly limited on time but I'd like to install the electronic boost controller and play with the jetting a bit more. I think I need to pull some fuel out since I've fixed all the leaks on the carbs.

Had to take the wife for an appt this AM so more shakedown boosting through the mountains. Somehow now I feel like the BR8ES are smoother through the rev range. Or maybe the cool mountain air is playing better with the turbo at elevation, not sure.

Also, on my drive yesterday I was cruising the freeway for a couple of hours and noticed my pan oil temps were 130 in the AM and 140 in the PM, and my oil cooler is already 2/3rds obscured with cardboard. I think I need to figure out a long term solution but I still need to do some more research and figure out what the options are.

@rossman it sounds like we have a fairly similar setup. Do you also have a 292-9 cam? Have you had it on the dyno? I put the BR8ES back in this AM just to be safe. Maybe when I get things dialed on the dyno the plugs will look better. @Zetsaz yeah to be honest I didn't think about it until I had installed everything lol. I'll order up a can of radiator black and maybe spray it in next weekend. Finally got notice from USPS that my electronic boost controller is coming in soon. After installing my old TurboXS controller, I think the best place to mount the solenoid and pressure sensor is behind the washer bottle where they will be hidden but accessible under the inspection cover. Inside the car I'm not sure where I want to mount the screen. I'm not a fan of having gauges and screens everywhere as I like the OE interior look. I'm thinking maybe velcro or double sided tape mounting it above the defrost/seat belt/choke lights in the center console. Or I could have it behind that panel under the pivot completely hidden since I could just pivot the panel up and hit the high or low boost setting.

Did another 150 miles today and the car didn't skip a beat on BR7ES and 10lbs of boost. I think I need to get new tires. I'm currently running r888s which are fairly old. My buddy hopped in for a drive and we lit up the tires in 1st gear at 30 or 40mph and spinning into 2nd as I was rolling into it on an uphill onramp. Also considering painting the intercooler black. I thought the fairlady Z grille would obscure it a bit more but at a distance it's pretty obvious, and I prefer the OE Z look with the coolers and rad support blacked out.

What was your engine setup? I read the same somewhere, probably here on HBZ that the projected tip mechanically advances your timing by somewhere around 4 degrees. The projected tip can get hot, preigniting the fuel. I switched over to the BR7ES last night, gapped to 0.028. The engine seems to idle a bit smoother and pulls to 6k without hesitation. The weather was cooler last night so not a great test, the outlet of the intercooler was frigid cold to the touch. Today I need to drive the car another 100 miles or so to pick up my 67.5 pilot jets and get breakfast with a friend. So I'll do some more testing on and off boost today. The main reason Im trying the 7s is I've noticed the 8s tend to get dark quickly, within a few hundred miles on my setup. This is probably because I live in one of the more densely populated parts of the US and traffic is everywhere. But I also noticed the plugs starting to get much darker after my drive yesterday where I was basically on boost for an hour in the mountains over maybe 2 hours of driving. The elevation change was also affecting my carb mixtures, Im sure. I think I'll stick to the 8s for track days, dyno or generally days when I know I'm going to be running the engine hard and at higher boost. But maybe the 7s would work better if I'm going to cruise long distance.

@rossman yeah that's what I've read too and what I currently run BR8ES. Some people on the FB groups were mentioning one step hotter to the 7 range would be better on the street and run the 8s on the track or dyno for detonation resistance. Maybe I should just stick with 8s unless the 7s really offer much better starts/drivability. Especially since Im 8.5:1 CR and running 91 pump gas

It is apparent I need to relearn how to drive my car. The way the turbo starts spooling in the 2k rpm range and peak torque is at 4k means I don't really need to rev it to the moon to approach high speeds, and response is really good. Corner exit is immense. The turbo spooling and BOV venting at lifts and shifts bouncing off the trees is really visceral. I think I need to find some way to record video from inside the car but I've attached a vid below of the cold start this AM and a snap from the drive. 20220930_063504.mp4

Technically I get today off from work but I still need to do a few things later. So this AM I'm going to go for a scenic drive into the mountains and keep shaking the car down. I was fueling up yesterday and I'm basically paying $7/gal for 91 here in CA. It's been getting ridiculous. Since fuel cost is so high I'm going to swing by my local race fuel station which is conveniently located at the start of the drive, and see how much some 100 octane is nowadays.

Tonight I went for a nice long drive. The pandemic is definitely over, traffic around where I live is terrible. All the time. But on the plus side, the car is running and driving the best it has to date. No more oil and fuel leaks, boost holding consistent at 10psi, and it pulls "turbine smooth" to redline. This weekend I want to find a way to check for boost leaks and try some 7 range plugs. I'll also be picking up some 67.5 pilot jets to try out, which are 1/2 step richer based on my tuning notes below. I'll also need to see if I can pick up my 250 needle and seats sometime soon. I'm currently using BR8ES plugs gapped to 0.028". Some tuning notes: I'm idling at ~11AFRs. The idle circuit carries the car from 11AFRs to mid 12s at boost onset 2.5k rpms. By 3k rpms depending on load and gear, I touch high 12s/low 13 AFRs and the mains start to tip in. When the mains tip in, the turbo is reaching peak boost and afrs are high 10s/low 11s by 4k rpms and peak torque. By redline at 7k rpms AFRs are mid-11s. I'm going to try 1/2 step richer on the pilot circuit. Maybe pull just a bit of fuel with larger airs past peak torque. And of course larger needle and seats as the motor just drinks fuel on boost into 4th and 5th gear WOT.