boardkid280z

I would say do some more searching. I think there are several guys running the 225 setup on high hp motors, even turbo'd. The pressure plate is smaller in diameter even if the flywheel is the same, so there is less moment of inertia which gives you more power to the wheels. Check out: http://forums.hybridz.org/showthread.php?t=147117

This doesn't sound like a problem with the AFM being out of adjustment, I wouldn't make any adjustments there, until you've checked everything else.

You say you went over a dam? Did your car get wet? Did you go through any large puddles? If so, your TVS/TPS could have gotten wet - this would cause the problem you are having. Very common for people who power wash their motors, without realizing how sensitive some parts are to water.

OK, so does it give you more area under the curve? Or does it affect the torque or what? I mean, it should be measurable on a wheel dyno if it makes a difference in the rate of acceleration. Basically, though, it will make your car faster, even though it doesn't increase your horsepower. Right?

Does your car still have a CAT on it? It's not clogged is it? Does the floor get hot?

Saw tonight, not bad - acting was ... pretty good. Could have been better, but it could have been a LOT worse. Action was decent. Not the best car driving scenes, but enough to get your blood pumping a little. Most of it looked real, except for the gay tunnel scene. I mean, who wants to see 5 dudes go up the same hole?? Lame that they killed a main character, but Diesel was back, so that was good and his acting seemed like it had improved, even Walker did a good job. Overall, good flick with cool cars, but could have used more footage of the cars (Z) and a little better action.

Lol, yep, sorry - my brain hasn't been working well this past weekend.

Well the 150psi is the number on the left of the ratio, and the number on the right is atmospheric (approximately). Which is 14.7psi, not 1 psi. So the ratio of compression for your motor is 150psi:14.7psi or 10.2:1 approximately.

I'd be interested in seeing evidence of this. I don't think the AFM is pegged before you hit boost, and I think adjusting the spring tension changes the final position of the potentiometer in the AFM (changing the amount of fuel at full boost) - whether the ECU is still reading inputs from the AFM at full boost is another question. I thought it just stopped reading inputs from the O2 sensor after a certain RPM.

Sounds like you can do a lot of adjustment to the AFM spring towards lean. 14 is richer than stoich and, honestly, it's too rich for cruise, you're just wasting fuel. Idle should be 14.5 or so, but you should really aim for drivability and fuel consumption. At cruise you should be at least 2 points leaner (16 instead of 14) and could easily be 3 points leaner (17). In boost you should be at least 2 points leaner (11 instead of 9) could easily be 3 points leaner (12). The only thing changing the spring affected for me was driveability before the car was warmed up. You said you noticed lean spots with a cold car, and that will likely get a little worse, but once the car warms up, you'll be fine. So just let your car idle a few minutes before you leave. Your car is slower than it could be and you're wasting fuel by running it as rich as you are - lean it out. Remember 17:1 is fine for cruise as long as it doesn't affect driveability and 12.5:1 is great for boost unless you're having other issues.

Thanks for pointing that out, I will try to PM bigphil to get more information from him. I would really like to do the comparison of one compressor with several different turbine housings. This will mainly affect spool-up, and therefore would move the knee point left and right. With a smaller turbine housing, the knee point could be significantly farther left from where I placed them.

Buick Grand National 1986-1987 turbo compressor map: Garrett TBO-348. There is precious little info on these turbos and this is the only compressor map I was able to find. Some sources said it was one of the biggest T3s Garrett ever made. Others said it will support 375-400hp (crank/wheels?). (from: http://www.turbobuick.com/forums/turbos-turbo-related-parts/247569-stock-tbo348-compressor-map.html) NOTE: This map is not like the other maps in that it seems to be focused on the highest efficiency regions (65%+ instead of 60%+) and the source mentions the map was limited to < 2.6 PR where the others would not be limited. I am not sure, but it seems like the speed line 120501 is not necessarily the max RPM for this compressor either, but on the other maps it does seem like the top RPM line is max. 6500 rpm red line points at 10 psi and 16psi are in the 60 to 65% efficiency region. 20 psi may still be in the 60% region too. 3750 rpm "knee" points for this compressor at 10 and 16psi of boost are in the highest efficiency region. When accelerating towards redline, the efficiency starts in the maximum efficiency area for 10, 16 and 20psi, thus performance is ideal during this period. It seems that this compressor can handle only slightly more boost above 20psi and it will run well from 7psi to 20psi of boost. The source says it is used up to 44psi, but it seems like it will just produce a lot of heat above 25psi This compressor will give great performance compared to the stock T3-60. Goldilocks says "great upgrade with good performance, not much room to grow."

Very cool man! Still pretty stealthy Ah yes, new clutches soon become necessary. When you have more power, you usually start driving like it and that's no good for an old underrated clutch. PS: Tip: build a cold air box for the air filter so it doesn't draw hot air from the engine bay.

OK, I am no expert or professional, but I have been spending a lot of time staring at compressor maps for the last couple of weeks. Nice car by the way! Is it an R32 with an N1 motor or what? Modified much? The link in your sig requires a login to view pics. Here is what I am trying to comprehend about compressor maps. It seems like the way the islands work is: if you are above, below, left or right of the higher islands, you're producing more heat. A possible explanation I am thinking of is that the center of your highest efficiency island - where you'll produce the least heat - is closer to 1.4 Bar than 0.8 Bar. I looked around for a long time for compressor maps of your turbos (it seems like they are T25s with 49 trim and 0.48 A/R, similar to the CA18DET turbo, and several others), couldn't find a good map though. Not many maps for the T25s. Anyway, for example: (I picked this map because it seemed to best illustrate my point) Therefore, in this map, draw horizontal lines across the map at different boost levels, we'll take the 2 boost levels you ran at, 0.8 Bar and 1.4 Bar. 1. At 1.4 Bar, (a pressure ratio of 2.4), as your motor climbs in RPMS, the airflow plot moves from left to right on the map. As it does it goes through almost the widest part of the highest efficiency island. So, it spends a lot of time in an efficient region of the compressor map where the compressor produces the least amount of heat. 2. At 0.8 Bar, (a pressure ratio of 1.8), the flow plot just barely cuts through the bottom tip of the highest efficiency island. So it is spending less time in the part of the map where the turbo is producing the least amount of heat, and more time in the part of the map where the turbo is less efficient and therefore producing more heat. What I am not sure I understand is this: If the turbo is in an area of lower efficiency, does that mean it is producing more heat, even if you are running less boost (you would think this would put less stress on the turbo)? Or does efficiency mean something else, not necessarily more heat? Maybe I am just unnecessarily associating/equating efficiency with heat production. It's interesting to me how different turbos have different efficiencies at different boost levels, like the GT ball bearing turbos - some of them lose efficiency above 30psi (2 Bar), others above a mere 18psi (1.25 bar). Of course it is the smaller ones that lose efficiency at lower boost, but even in similar sized larger turbos (GT35s etc) different compressors seem to have noticeably different boost levels at which they are most efficient. Some like 15-20 psi, and others like 25-30 psi.

Great progress man - post a vid when it's running, and lots of pics before and after! Is there any advantage to running the Kameari valve cover? What car is going into? The white G-nose, is that yours?

Great! Congrats man, you're going to have a lot of fun. It would be nice to know if it ran or not, but $300 is a great deal. I paid $400 for mine a month ago and it was barely drivable. But it was running, and runs pretty smooth. I got a set of wheels out of it too.

LOL Great video, Phil. That sounds like an awesome upgrade. The car probably feels a lot faster since it's so much lighter , no doors, hatch, etc.

Longer duration will lower cylinder pressure? Won't that let more air in the piston, causing the density of the air to be higher when it's compressed, causing higher cylinder pressure?

Yea, I meant fitting the Tbird turbine housing, but I guess there's no reason it shouldn't fit.

Very cool man. Eager to see pics of it, and the turbo with the Ultimate Internal Wastegate mated to it, to see if my speculation about it fitting was correct.

I didn't see this link anywhere in this thread and it is a great reference for stock wheels with dimensions and weights. http://kmhafer.datsun510.com/wheelchart.htm (if the link quits working, the page is on http://www.dimequarterly.com under Technical -> Suspension)

Oh yea, I forgot, I am running without a stock O2 sensor. But I don't think the O2 reading affects the fuel curve at WOT, only at partial throttle/cruise. So I guess that may be part of the problem when he's easing into boost.

That's what I've been doing this past week. I swapped my second turbo motor into my 78 coupe and wanted to put it in completely stock (I used to have intercooler, Megasquirt). So I swapped everything over exactly from the '83, except for the 3" downpipe and exhaust. So the car is a: 1978 280Z with a bone stock L28ET and L28ET EFI installed. My AFM from the ZXT was also not sealed, so when I installed it, I drove it a little and turned the AFM spring a little to the rich side since I didn't know if the PO might have loosened it to make the car run leaner and I wanted to be safe. I didn't have my wideband in the car till last week, so I found out I was running pretty rich, and the original tension on the spring which I had marked was actually pretty close to where I needed to be. After a few runs (and a quick scare past what looked like a motorcycle cop coming the opposite direction going 80+ on a highway service road - 45mph limit - who then put on his blinker, and I floored it and "got away from him"), I got the AFRs where I wanted them. Flooring it in 2nd and 3rd gear, the AFRs stayed in the high 11s most of the RPM range. They start out around 3000RPM (full 7psi boost in stock guise) in the mid 12s then drop to the mid 11s by around 3500RPM and then by 4750RPM the AFR is back up in the mid 12s. So if you plotted it, it's kind of a flat slope with a long dip in the middle. Not exactly what we're looking for, but I don't know how to get it any better. I don't want to run any leaner than mid 12s anytime I'm at WOT. Another thing my car does, which has gotten worse since I leaned it out with the wideband: it bogs down a lot below the boost threshold until it's warmed up. You have to baby it, or just let it warm up. I don't know if it's too lean now or what. Even after the car has warmed up it still seems really hesitant below 2500RPM. I do need a new cap, rotor and wires, so maybe that will help some. If you plan on sticking with the stock EFI for a little while at least, I think you'll find an improvement by adjusting the AFM spring. You said you're around 12.5 to 14.5 when you're just driving around. That's really pretty reach, any time you're not over 50% throttle I think above 14.5 AFR is just fine, and when you're just cruising 16:1 or higher is normal. My car was running 14.5-17AFR when I'm just driving around, and that'll be much better on gas mileage too. What AFR during boost are you going to shoot for? I found that after the adjustments my car was still pretty lean in low boost conditions (0-5psi, 75% throttle) - 13-15AFR. Until I got on the throttle, it didn't add as much fuel as I would have expected.

OK, ok. It's his first post, let's give him a break. First of all, read this thread: http://forums.hybridz.org/announcement.php?f=65&a=2 Especially # 2, 3, 4, 5. Then check out the Tool Shed and see for what reasons other threads have been junked mercilessly. Then come back, edit your thread and title and hopefully get some responses. Do this post haste or your thread will end up in the tool shed. Mind: specific title/thread description, NO CAPS!!!, spelling (fule, dam, dallors, inake, ...)

So, grooves, anyone, anyone? Seriously though, that PDF shows CLEAR results of a definitive improvement in efficiency, fuel consumption, and more importantly, BOTH horsepower AND torque from simple grooves. No reason this shouldn't translate into our motors. Has anyone done this?? As I was reading about it and seeing pictures, I was wondering if these mods are mainly beneficial for motors with flattop pistons since these have the quench design and really make use of it. Would there not be a noticeable effect on a dished piston motor, like most of our turbo motors? Or would there still be a similar benefit?