JMortensen

Don't reuse main or rod bearings. They aren't that expensive and they along with rings are the major wear items that you just don't want to use over and over. Being that they aren't hard to come by and they aren't expensive it's just crazy to reuse bearings.

The wing in the picture is stalled. Normally wings don't have airflow like that, and the flow should be relatively equal across the surface of the wing. That is an extreme example, but I used it to point out that the part with the yarn pressed against the wing has some pressure on it, and the part where the yarn isn't pressed against the wing has no pressure. I think you could get much more effective downforce if the wings extended off the side of the car like a plane, but that might make it difficult to drive though, especially at an autox... As far as reasonable modifications go, the body has the effect of putting "dirty air" from the boundary separation layer onto a low mounted wing. That's why we're discussing the VGs, because if they can clean up the airflow and reduce the boundary separation layer then we can make the wing or spoiler more effective. That's what the thread is really about, we've just gotten a bit sidetracked.

That sounds like the outer pinion bearing is bad to me. When mine was bad I got a speed sensitive whine. The faster you go, the higher pitch it gets. Welding the diff shouldn't affect the noise of the diff at all, it just makes the tires chirp when going around corners.

I'm looking at different options to install dual masters. I know I've discussed all of these here at one point or another, now I'm trying to make a decision. 1. Buy a complete Wilwood or Tilton pedal assembly. I'm thinking I'd do the masters in the engine compartment. I don't think this would be terribly difficult to install as it just has to be bolted to the firewall and the appropriate holes drilled, but I've never done it before. One major question I have is what happens to the steering column in this case???? Something like this is what I have in mind: http://www.pitstopusa.com/detail.aspx?ID=1155 http://www.tiltonracing.com/content.php?page=list2&id=4&m=b 2. Buy an already modified Datsun pedal box from DP racing. This option is $500 something with masters. It puts the masters inside the car, so if they leak they drip on your shoes and the reservoirs must be remotely mounted. 3. Buy John Coffey's new super wazoo dual master setup from http://www.betamotorsports.com. Bolts on, no fabrication, don't even have to remove the pedal box (mine's already out though) and it is $454.95 with no masters and I wouldn't have to screw with the clutch at all. I think this is the nicest option for sure, but I don't have a lot of money. 4. Buy a balance bar assembly and attempt to cut up my pedal box and modify it to work. I understand that this isn't all that hard to do if you know what you're doing. I don't know what I'm doing though so this would be an adventure to say the least. Iskone's car has this done to it, and I know tube80z has done it as well, pics of Iskone's car in this thread: http://forums.hybridz.org/showthread.php?t=111465 Anyone done #1 or #4 before? Easy, hard? At this point I'm getting a bit tired of big projects and although I've turned the corner and my car is starting to go back together instead of coming further and further apart, the sooner it gets completed the better. That means the cheaper and easier this is the better. I guess I'm trying to find that sweet spot between cheap and easy.

At least we've isolated where you are wrong. I think maybe you're confused because you equate fast moving air and low pressure. That's true, but you don't realize that there is no air density in the red area, so it is not slow moving high pressure air. It is a void, or a lack of air, a vacuum. So it's pressure is lower than the low pressure air in the blue box. Take a look at figure 10 in the Mitsu paper. It deals with air VELOCITY. You can see the reduction of the blue boundary separation layer, which is a vacuum, behind the rear window with the VGs installed. So there is NO velocity at the base of the window. The air doesn't go around the sides and top of the vehicle then just suddenly stop in that area. There is no velocity there because there is no air there, because it is in the boundary separation layer. Then check figure 11 in the Mitsu paper, this one shows PRESSURE. You can see side by side that the area at the base of the rear window has higher pressure with the VGs than without. This is because of the smaller boundary separation layer. If you could get the boudary separation layer totally eliminated and get that air to flow directly across the body, the pressure would be higher still. I don't know how else to prove the point, so I'll let someone else take over the argument if they care to.

duplicate

Here is another example. Look at the picture and answer the following question: Where is the pressure? Is there more pressure in the blue box where the "low pressure" air is not separated from the wing and the yarn lies totally flat against the wing, or is there more pressure where the air has separated from the wing in the red box and the yarn is floating around and moving in all directions?

I think "stall" is the wrong word here. How else would you explain that you can improve take off and landing and slow speed manueverability with the VGs? Unless you think that the wing on just about every aircraft is stalled just as the airspeed is high enough to take off. I think by making the air stick to the top of the wing it make the flaps more efficient and allows the flaps to work better, and that's where your increased lift comes from, but what the VGs really do is reduce drag. It reduces the vacuum created by wings and that makes it faster and easier to fly and makes the controls more responsive because the flaps aren't sitting in a turbulent vacuum, and that vacuum isn't trying to pull the plane backwards. Getting back to the automotive world, did you not agree that the Mitsu paper says that the downforce is increased by adding the VGs? How else do you explain this statement: "Application of the VGs of the optimum shape determined through the aforementioned analyses to the Mitsubishi LANCER EVOLUTION showed a 0.006 in both the drag and lift coefficient" and even better, this: "As a result of the verifications, it is confirmed that VGs create streamwise vortices, the vortices mix higher and lower layers of boundary layer and the mixture causes the flow separation point to shift downstream, consequently separation region is narrowed. From this, we could predict that VGs cause the pressure of the vehicle's entire rear surface to increase therefore decreasing drag, also the velocity around the rear spoiler to increase, and the lift to decrease." "...VGs cause the pressure of the vehicle's entire rear surface to increase therefore decreasing drag" sounds just like how I imagine the plane wing to work. The plane wing doesn't get more lift from the VG's, it actually gets more pressure on the top of the wing when compared to the boundary layer it would have with no VGs. This airflow and pressure can then be used to greater effect by the control surfaces, and THAT can be used to generate more lift.

It's 5 times as much searching for belts and clipping them all together, and remember they aren't retractable. Plus the added hassle of installing a roll bar or strut tower bar to mount the harness to. I would NOT put belts on a strut tower bar that had rod ends on the ends. I would only attach them to a strut bar that was one piece of tubing welded between the strut towers. Then you need a seat suitable for harnesses. The stock seat isn't good for use with harnesses because it has no holes for the harnesses to go through. So if you're willing to put up with all of that, I'd say it is safer.

If you go all the way to the end of the thread, they do reinforce the spring mounts and install a weight jack in the back as well. They also have some improved front suspension pieces. Still could have tied the main cage to the strut towers through the firewall, but it's actually a lot better than just the first set of pictures.

They have an awful lot of support going to what looks to be a rear SHOCK tower, not a rear strut tower. I just checked and I found that the Fit has a beam axle in back, so bracing that shock tower isn't exactly the highest priority. I don't know where the springs hit the chassis or if there are any control link points that might be reinforced, but it doesn't look like there is any reinforcement there. What I thought was redundant was the A pillar bars. They have the bar that goes forward to the dash which I think is bent too much , then another bar right behind it that follows the pillar itself. I think the X from the main hoop to the rear shock tower is heavier than a diagonal in the main hoop itself, and the X from the shock towers to the back makes it look like the guy is planning on taking a pretty serious hit to the rear. The gussets from the a pillar to the roll cage and roof I like, although the diagonal gussets between the A pillar bar and the roof bar seem excessively long, same with the ones from the main hoop to the bar above the windows. And as Cary said, nothing going out to the front suspension points or drivetrain mounting points which I would think are the most important ones in this car. Funny, because I just glanced at it at first and thought "Nice!" then I saw the other critical posts and started to realize, maybe it wasn't so great after all...

That's not what I intended. I'm saying that I think the low pressure from the VGs might be higher pressure than the turbulent boundary separation layer, and that this would explain why the Mitsu engineers showed increased downforce despite the increase of "low pressure" air over the rear window and trunklid.

I haven't seen anyone in this thread dispute that statement.

Get a Haynes manual. It shows the cam timing marks, where they should align, and how to advance the cam timing so that the marks are in the right spot.

Never heard of the water pump causing that much pressure. I had a friend miss a shift and probably hit 10,000 rpm in her Z, no freeze plugs let go. I've got friends who rev their L4s to 8000 rpm, never seen any of them lose a freeze plug. I think the most likely idea so far is that there is a leak between the cylinder and the headgasket and that this is allowing the compression to pressurize the coolant. I suppose it could also be a cracked block doing the same thing.

Just MHO, but on a stockish motor it takes a lot of advance to cause detonation and a LOT of detonation to damage pistons. The PO would have to be a special type of moron to keep driving until damage was done. Not to say it doesn't happen, just that it is unlikely and takes some "What's that noise? F it, turn up the radio!" kind of mentality to do it.

This is exactly where I think you and bjhines have it wrong. My theory is that there is literally NO steady airflow at the back of the hatch on a Z. There is a vacuum, and whatever air does come in to fill the void isn't coming into the void in a uniform enough way to eliminate the vacuum. This is why we get exhaust fumes sucked into the car. What I think you guys are missing is that there is a great big hole or vacuum behind and ABOVE the car where the boundary layer is. So if you only have random turbulent airflow as the surrounding air trys to fill the void on the hatch and the back of the car as well, then you get vacuum or suction or lift or whatever you want to call on the back of the hatch. Here is a simply explained, common sense website with a fairly good explanation: http://selair.selkirk.bc.ca/aerodynamics1/drag/Page2.html Like the swimming pool example, we are pushing air out of the way in front and fighting the vacuum behind when we drive a car through the air. I think you guys are just underestimating the size and location of the vacuum created behind our cars. I don't know how bad the boundary separation layer is on a Z. All I know is it can suck fumes being expelled at pretty good velocity out of the tailpipe back towards the car and into any small leak in the gaskets or seals there. I think that the size and strength of that area of vacuum is what we really need to find out to resolve the argument, with and without the VG's of course. Regardless, if there is a vacuum above the back of the car that air is rushing into to fill, it seems logical to me that you would have more pressure (and downforce) on the back of the car when you eliminate the turbulent vacuum layer from the surface of the car, even if you only had a steady flow of high velocity low pressure after the fix was made. It's not the best case scenario for downforce, but I do still think it's better than having a huge vacuum there. I've also been looking at websites where they've alternately used vacuum inside a wing to suck the airflow to the wing removing the boundary layer into the wing itself, and others where they put high pressure air into the boundary layer fill the boundary layer and keep air attached to the rear section of a wing. I'm seeing more possibilities there, like drilling holes in a Lexan rear window to try and equalize the pressure. Seen that on enough racecars... Maybe even put some ducts from the side windows to the hatch and reroute some air into the boundary layer. Again, it seems like this would reduce lift and drag, even if no spoiler were used.

Having been in a rollover with a stock seatbelt I can tell you that it sucks when your shoulder slides out from under the belt, because then you can slide up another 4 or 5" closer to the roof, and your head slams back and forth between the roof and the window frame. This more you roll, the suckier this gets. I don't know how many rolls I did, but it was plenty sucky by the time the car stopped.

This reminds me of people who don't wear a seatbelt and back it up with the reasoning that if they're in a rollover there is less of a chance that they'll be ejected and thrown clear of the wreck. I mean really, how often is another car going to roll over the roof of your car? The main issue with harnesses has to do with them being installed wrong, and the biggest issue there is the angle that the harness makes as it goes over the shoulders and back to whatever they are anchored to. If the anchor point is too low (like those dumbass Honda guys with the 4 point "racing harness" clipped into the rear seat belt) then when you go forward in an accident your spine also gets compressed down. There is a proper angle for the belt to sit at. I want to say it is from 5 to 15 degrees up from the anchor to the shoulders, but it's been a while since I've looked at that info. Other than that harnesses are a PITA on the street, especially the latch kind like I had. I used it on the street for about a week, then put the old one back in on top of the harnesses. I hooked the harness up behind the seat and used the stock seatbelt, then when I went autoxing I'd hook the stocker behind the seat and use the harness.

Yep. At least now you know for sure...

Valving might be different, but other than that if it bolts up you should be good to go. I know some people that run a wagon at autox and they had trouble lowering it too much because the axle hit the floor. I have a KICK ASS suggestion for leaf springs too! Check out the sliders mentioned in this article: http://www.afcoracing.com/tech_pages/leaf.shtml Here they are for sale on AFCO's website: http://www.secureperformanceorder.com/afcostore/getproduct.cfm?CategoryID=14&ClassID=180&SubclassID=851&ProductID=985 I used these things on my Toyota truck when I was autoxing it. It lowers the car because the shackle is eliminated, and it eliminates the slop in the shackles. When you stomp on the brakes in a leaf sprung car the shackles "stand up" and this creates excessive nose dive. Also when you corner hard the shackles lean over and the rear end can actually move side to side. On some cars with really worn leaf spring bushings you can actually see the inside tire come out of the fenderwell on hard corners. The sliders eliminate that as well. And they're virtually stiction free. When I first put them on my Toyota and the bearings were all nice and new you could move the rear suspension by pushing down on the bed WITH ONE FINGER!!! I used those and some traction bars and that thing was freakin planted!

It could be a 260 or a 280 distributor. I think the 260s came with electronic ignition as well. If you advance the timing too far and you're not pinging, you're basically just giving up hp. Retarding timing will burn valves, but I don't think advancing a little farther than optimal is going to hurt anything as long as it isn't pinging. Gray/black smoke? Compression test would help, maybe bad rings. Hard to say. Do that searching like you said and you might come up with something.

Correct. My mistake. Ported vacuum... As far as cam timing vs ignition timing, they're TOTALLY different. The more the cam timing is advanced the better low end power you'll have, and top end suffers. Retarding the cam timing gives more top end power. I don't know why your cam timing would be on the #3 mark, but if it's due to a slackened chain that's a pretty good indication that the chain needs replacing. If you haven't been into the L series timing chain before do a search. If you start screwing around in there you're liable to lose the tensioner (it will fall out if you give the chain too much slack), and then you have to pull the front cover to put it back together. On the igntion you need advanced timing to run at higher rpms. Generally you get the best hp somewhere in the mid 30's degrees advanced. Go farther than that and you're likely to LOSE power.

1st thing to do is figure out what distributor you have. You've got 2 forms of advance on any Z or ZX distributor (except the 280ZX turbo). Mechanical or centrifugal advance has weights inside the distributor that swing out as the distributor shaft spins faster and faster. When they hit their stops, this is referred to as the advance being "all in". So this is 17 or 19 degrees on the ZX distributors, more on the 240 thru 280Z distributors. If you start with about 15 degrees advance at idle on the ZX distributor, that gets you into the mid 30s all in, which is good. The vacuum advance is more for mileage and throttle response at low rpms. If you don't need it, you can disconnect it. It provides more advance at high vacuum situations like idle or part throttle. When you stomp on the gas, there is not enough vacuum to actuate the vacuum advance mechanism, so it relies on the mechanical + the static advance (where you set the distributor with the timing light at idle) for total advance. The ZX vacuum advance mechanism sucks and it is almost always broken. When it breaks it can allow the pieces inside the distributor to hit each other. You can fix the vacuum advance if you want to use it for the extra mpg or two. Harbor Freight occassionally has the timing lights with the advance function built in. I bought one a while back for $25 I think. If you have the advance function then you can just set the dial to 32 or whatever and set the timing on the 0 mark.

Did you try a couple squirts of oil and redo the compression test? That would tell you for sure if it was rings. If the compression #'s don't jump right up, then it's leaking somewhere else, out of a valve or headgasket or something. Takes 5 minutes...