duder280z Posted May 6, 2008 Share Posted May 6, 2008 Hello HybridZ! I'm a new first time Z owner who dove right into an interesting one. It's a 77 280z that was built in the 80's for autox racing. It has a real old school style turbo conversion on what I believe is the origional motor, it doesn't have a wastegate, instead it has a pop off valve on the intake tube that regulates the pressure and acts as a blow off valve between shifts. I'm not sure what kind of ecu it's running(stock?) but I'll look at it when I get a chance. It's only boosting to 4psi, I think that's all it was meant to according to the paperwork I got with the car. It has an adjustable fuel pressure reg and a guage showing 50psi at idle. The real mystery so far is this knob on the center console that is next to the hazard switch. The previous owner had no idea what it does, when I turn it the idle goes up or down and the car seems to respond a little different. The previous owner also said it made the exhaust temp go up or down (it has a pyrometer) at freeway speeds a bit (I didn't see a noticable difference). Could this knob adjust timing somehow? I'm sure one of these days I'll track the wires connected to it, but for now I don't want to tear into the interior as it is in really nice condition. Any thoughts? Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted May 6, 2008 Share Posted May 6, 2008 maybe... But I demand lot of pics of the car first Quote Link to comment Share on other sites More sharing options...
Challenger Posted May 6, 2008 Share Posted May 6, 2008 Yes, lots of pics. Good to see another 2+2. Im guessing the car is maroon... Quote Link to comment Share on other sites More sharing options...
duder280z Posted May 6, 2008 Author Share Posted May 6, 2008 maybe... But I demand lot of pics of the car first I only have a few pics right now, I'll charge up the camera and snap more soon. Quote Link to comment Share on other sites More sharing options...
duder280z Posted May 6, 2008 Author Share Posted May 6, 2008 Yes, lots of pics. Good to see another 2+2. Im guessing the car is maroon... The pictures are missleading, it's purple. I'm changing that asap.Probably flat black rattle can for now. Down the road maybe a flaky dark grey. Needs body work and spoilers first. That homemade grill has to go too.... Quote Link to comment Share on other sites More sharing options...
Challenger Posted May 6, 2008 Share Posted May 6, 2008 Hey I was right! These were the pictures I had. It was on ebay a while back. Quote Link to comment Share on other sites More sharing options...
duder280z Posted May 6, 2008 Author Share Posted May 6, 2008 Hey I was right! These were the pictures I had. It was on ebay a while back. Yeah, I traded with a guy from Stanwood for my motorcycle. Amazingly little rust, great interior, and a decent runner. It has some issues as I suspect most do, the climate control is all unhooked, it's gonna need a head gasket soon(starting to leak oil out the passenger side), the low beams don't work and the high beams aren't very high, mostly typical Z stuff from what I've been reading the last few weeks. I'd like to go full on MSnS with a holeset, but all in due time. It's my DD so first things first. Quote Link to comment Share on other sites More sharing options...
jeffer949 Posted May 6, 2008 Share Posted May 6, 2008 If i remember correctly from what i was told from Speeder(hey had that kit at one point) the nob is a potentiometer that adjusts the resistance to the coolant sensor. It adjusts how rich or lean you are going to run. thats why the exhaust temps would go up when you turned it because you where making it leaner. which means its running hotter. Guys put those in on there cars all the time to help with tuning. This just came with it in the kit. Quote Link to comment Share on other sites More sharing options...
duder280z Posted May 6, 2008 Author Share Posted May 6, 2008 If i remember correctly from what i was told from Speeder(hey had that kit at one point) the nob is a potentiometer that adjusts the resistance to the coolant sensor. It adjusts how rich or lean you are going to run. thats why the exhaust temps would go up when you turned it because you where making it leaner. which means its running hotter. Guys put those in on there cars all the time to help with tuning. This just came with it in the kit. Hmmm... primative tuning is very interesting. That may explain why when I turn the knob up it has better throttle response and acceleration. I'll have to play with it some more. The car tends to fall flat a bit when it's on boost and at full throttle, but does better when peddling the throttle. I'll try cranking the knob all the way up and see what happens. I would also like to install my A/F guage to see if it shows any signs of leanness as well. Thanks jeffer Quote Link to comment Share on other sites More sharing options...
Daeron Posted May 6, 2008 Share Posted May 6, 2008 If i remember correctly from what i was told from Speeder(hey had that kit at one point) the nob is a potentiometer that adjusts the resistance to the coolant sensor. It adjusts how rich or lean you are going to run. thats why the exhaust temps would go up when you turned it because you where making it leaner. which means its running hotter. Guys put those in on there cars all the time to help with tuning. This just came with it in the kit. Good call, it is an old school trick to fool the simple ECU.. not unlike "tweaking" the AFM to run richer, or adding the rising rate fuel pressure regulator. Honestly, its not worth it anymore, thanks to megasquirt, but its cool to find for the street cred. Obviously it will have a direct impact on your fuel mileage, and if you run it too lean and hit hard throttle you risk detonation with potentially disastrous consequences.. so find a good spot, but don't try to skimp too much on gas unless you granny the throttle when you do. Quote Link to comment Share on other sites More sharing options...
Jesse OBrien Posted May 6, 2008 Share Posted May 6, 2008 ...find a good spot, but don't try to skimp too much on gas unless you granny the throttle when you do. Which kind of defeats the purpose, IMHO. I definitely think finding a good spot is paramount, then leave it. OR, you could always just tune it in to that good spot and ditch the pot altogether. That way you don't have to worry about it corroding and ruining your signal (causing all manner of weirdness to track down). Just my .02 Quote Link to comment Share on other sites More sharing options...
duder280z Posted May 8, 2008 Author Share Posted May 8, 2008 Thanks for the info guys. Today I found the wires from the knob in the engine compartment, spliced into the coolant temp sensor just like you said. I don't want to get rid of the pot because the car only goes good full throttle with it cranked up. If I left it like that my milage would go from bad to worse. I need to figure out how to squeek some better MPG's out of this thing. I haven't been able to calculate it yet, but so far it isn't looking good. The fact that I only do city driving and the 4.11:1 gears don't help. It's still running the stock air box, that gots to go for sure. I'm currently in the process of cleaning up connections. Any other tips? Quote Link to comment Share on other sites More sharing options...
rreford Posted May 10, 2008 Share Posted May 10, 2008 woww - remember buying one of those pots back in the day. just like you said, designed to fool the ecu (throwing that term around loosely - think pong instead of atari 2600). richens the fuel mixture, kills gas mileage - does nothing for an NA 280 Quote Link to comment Share on other sites More sharing options...
skib Posted May 11, 2008 Share Posted May 11, 2008 Hey duder was this on craigslist a while back? nice to see another NW zed head around! check out the Z car club of WA [zccw.org] and NorthWest Z [Northwestz.org] dont miss the Canby event in June! Quote Link to comment Share on other sites More sharing options...
duder280z Posted May 11, 2008 Author Share Posted May 11, 2008 Hey duder was this on craigslist a while back? I'm sure it was, I heard it was on ebay too. I picked it up a week ago as a trade for my motorcycle. I think I got the up side of the deal. The real winner is the car, it is in need of tlc and driving that it wasn't getting with the previous owner. He would put around 1000 miles a year on it, so it sat around a lot. No more, she's my DD now. My commute is short, but now I go the long way on purpose. Quote Link to comment Share on other sites More sharing options...
RedEvilrps13 Posted May 11, 2008 Share Posted May 11, 2008 +1 for it being a 2+2 but i really dont like the way the rear wide fenders look from the rear.... Quote Link to comment Share on other sites More sharing options...
skib Posted May 11, 2008 Share Posted May 11, 2008 well good to see its in good hands now and hopfully ill spot this Z in the NW some time, im interested in seeing it in person Quote Link to comment Share on other sites More sharing options...
duder280z Posted May 13, 2008 Author Share Posted May 13, 2008 Honestly, I know whatcha mean. I'm not a big fan of the rear view either. I'm trying to figure out what to do about it. I know from looking at the Jim Cook racing catalog that it looks a lot better with screens in the holes and some inner fenders(so you can't see the tire through it), but I'm trying to decide wich way to go with a spoiler. A wing of the right width might even be more appropriate for this kit, hmm(nothing tall or giant). Also thinking about getting rid of the bumper and shaving the roll pan. Or would it look better with a different bumper? Either way that big ole eye sore has to go. Then there's the front spoiler issue(or lack thereof). I'm not sure if any of them would fit except a lip spoiler(I kinda like those any way). Decisions decisions.... It'll be a while before I can afford any of that anyway. First body mod is to get rid of the pastel early 90's pinkish purple. But before I do I'm gonna mask off some racing stripes and rattle can 'em in flat black just for fun. Might even look pretty cool. When that look gets old the whole thing is going flat black until I can decide on spoilers and finish body work. I'm open to suggestions and ideas. Quote Link to comment Share on other sites More sharing options...
Challenger Posted May 13, 2008 Share Posted May 13, 2008 Ford dark shadow grey is a nice color on a 2+2. Quote Link to comment Share on other sites More sharing options...
Gollum Posted May 13, 2008 Share Posted May 13, 2008 Please more pics of the engine. Using the low temp circuit to richen mixture isn't a good idea imo, because it's not increasing the max output of your injectors. Adjusting fuel pressure is much better for minor tweaking needing more fuel, but that's a bit hard to adjust from the cockpit You're only getting 4PSI? Should be getting closer to 5-7, not over 7 though. I'm curious what turbo to intake pipe that is. It isn't stock that's for sure. Quote Link to comment Share on other sites More sharing options...
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