TimZ

The displacement gain from the LD28 crank alone is only about 6%. That's roughly the equivalent of 1psi of boost. Not too big a difference, IMHO. Also, your price difference is going to be more than just the $200 for the crank. The stock piston/rod combos that are used for this swap yield compression ratios that are way too high for a turbo. You will have to have custom low compression pistons made, and they cost on the order of $125 each. So, with just that, your price just went up to around $1000. If you are planning on a maximum effort turbo motor, you should buy forged pistons anyway, so most people that build these up don't associate the pistons as an extra expense that came from the LD28 crank. However, it didn't sound as though you were planning on doing forged pistons just yet... [ October 28, 2001: Message edited by: TimZ ]

quote: Originally posted by TimZ: The thing with the Z strut, though (at least on my '78), is that the strut tube is directly behind the spindle, so there should be very little difference between the strut travel and the wheel travel. At worst, I would guess that the strut travel is 90% of wheel travel in this case. Actually, now that I'm thinking a little more about it, the Z strut (on my '78) is actually part of the spindle assembly, and moves exactly the same amount as the wheel - it physically cannot move independently of the spindle. ...And now that I've thought about it few minutes longer, I'm thinking that there is some difference between strut travel and purely vertical wheel travel, but this is due to the fact that the strut is not purely vertical. Instead, the strut is angled inward slightly. Interestingly, this would mean that the vertical wheel travel differs from the strut travel by the cosine of the angle that the strut has from vertical (the strut is on the hypotenuse of that triangle). So, if this is correct, in this particular case, the strut travel would acually be GREATER than the vertical wheel travel. Now, some of this effect will be negated by the fact that the bottom of the strut doesn't move purely up and down, but rather in the arc prescribed by the a-arm. However, I think that the strut angle will still be the dominant factor here, simply because it's longer than the a-arm. ...Has anybody's head exploded yet?

Okay, now I'm confused. It looks like you are showing the spacer on top of the strut cartridge, so that it's bottom sits on the bottom of the strut tube. Why would you want to do that? It doesn't make sense. This approach negates that amount of suspension travel for no reason. The spacer should always go under the cartridge. Am I missing something here? Also, on John's point about the strut not travelling as far as the wheel, this is a known characteristic of suspension geometry. The strut travel is some percentage of the wheel travel, which is determined by where the strut (or shock) attaches to the a-arm. For instance, if the strut attachment point is in the middle of the a-arm laterally, then the strut travel will be 50% of the wheel travel. Same theory goes for sway bar effectiveness, btw. The thing with the Z strut, though (at least on my '78), is that the strut tube is directly behind the spindle, so there should be very little difference between the strut travel and the wheel travel. At worst, I would guess that the strut travel is 90% of wheel travel in this case.

When you start running high boost, it's usually a good idea to close the gap up a bit. This is purely to reduce misfires, as it gets increasingly more difficult to ignite the mixture as boost goes up. I'm currently running 0.030"

100 sounds a little low, but I'm not sure what the stock ZXT is supposed to come out at. This can be caused by quite a number of things, though. More importantly, the fact that they all measured the same indicates that the pistons are most likely not broken (unless they are all broken exactly the same ). If you had a broken ring land, I would expect the compression to be much lower than that. Bottom line - Sounds like you are okay...

Scotty... If you want to keep the vacuum caps on, try putting a small TyWrap around them. That usually works pretty well for me.

My guess is that the vibration in the hose was from high frequency pressure spikes in the line itself. This could very easily get introduced by the pump, in fact this is precisely what the mysterious fuel damper was for in the FI Z's. Since the fuel is not particularly compressible, the pressure spikes will travel right down the fuel line, and excite anything in their path (like the regulator). If you can feel the lines vibrating at the FPR, then this is probably the problem. This shouldn't be much of a problem with carbs, but it can cause inconsistency in a FI system, since the pressure becomes unpredictable. You might consider installing some kind of damper in the fuel line to help reduce the pressure spikes. I'm thinking maybe a T in the line, with a few inches of pipe or hose that is sealed on the end, and installed vertically. If you make sure that this section of hose has air in it, this should act as a filter for the pressure spikes. They do this in home plumbing all the time, and for much the same reason.

quote: Originally posted by pparaska: I'm having problems with the turbo small engine needing more clutch than a V8. Well...define 'more clutch' . I never said anything about the CFDF clutch for anything but a turbo L6, except maybe the fact that comparing the same brand clutch for the L6 and a V8 is apples and oranges, due to the different pressure plates used and the different diameters. Remember, I'm just repeating what a Centerforce tech told me regarding the torque capacity of the CFDF, after mine started slipping at around 1500-2000 miles. As I've mentioned in other posts, this was for the 220mm clutch, not the 240mm, but that difference would still only bring you up to ~300lb-ft capacity. A reasonably prepared high boost Turbo L6 could easily exceed this. [ September 30, 2001: Message edited by: TimZ ]

Blk...your calculations for surface area are on the right track, but you have to remember that the friction surface is a ring, not a solid disk. You would need to get the area of the inside radius, and subtract it's resulting surface area to get the area of the ring. Also, probably more important than the actual surface area is the longer moment arm that the larger diameter disk creates.

quote: Originally posted by 383 240z: A hole in each lobe? I'did not see that during the valve adj. but ther is also nothing over the cam that I could see spraying oil on to the cam I did notice holes on the cam towers though If there are uncovered holes on the side of the cam towers (passenger side, assuming it's left hand drive), that is most likely your problem. If your head was originally equipped with a spraybar, and no longer has one, these holes MUST be sealed off, and you MUST use an internally oiled cam. The holes (assuming I'm reading your post correctly) are the oil supply for the spraybar - if they are not sealed, then they are just pi$$ing the oil out the side of the cam towers, and very little (if any) oil is going to the cam. Motorsport Auto sells blockoff plates for these hole for about $4, BTW...

The externally oiled cams have a spraybar that is attached to and gets it's oil from the cam towers. An internally oiled cam does not use the spraybar. They are hollow and have oil holes in each lobe that apply the oil. Which is better? For most applications, it doesn't make much difference, so long as both the cam and head are setup for the same system (i.e., don't use a solid cam without a spraybar). Some people swear by using the spraybar with an internally oiled cam, and this has been the subject of much debate. Many have used this setup with no problems, but I still think it's risky. My reasoning is that there is a restrictor built into the block that limits the amount of oil flow to the head. If this is not removed, then the limited supply of oil will now be split between the cam and the spraybar. This will lower the oil pressure in both, and it's quite possible that you'll actually end up with LESS oil actually getting to the cam lobes (if the pressure is too low, the oil from the spraybar won't actually reach the cam). Also, if you remove the restrictor, you will most likely alleviate this problem, but that restrictor was there in order to keep as much oil pressure as possible at the crank main bearings. If you don't have a ton of experience with L-series engines, I'd stay away from such a setup.

This can happen for several reasons. What oiling system did the cam use (internal or external)? Were the rockers replaced with the cam? Is the wipe pattern on the rocker pads completely on the pads? What do the rocker pads look like? Are they scored or pitted? Are all of the lobes damaged, or just a few? If just a few, which ones?

Generally, this refers to flywheel HP.

quote: Originally posted by R0N: Hey Clint... I almost decide going to the 57 trim since TIMZ has it and is known to be Fast. I think I will try out the 54 trim. On TimZ's turbo, I am not sure if he got this option... Whoa, guys... Thanks for the kind words, but my turbo is a Turbonetics T64. The turbine side is a full T04 (it's not a T3/T4), with an o-trim wheel and .69 AR. As far as the 11 degree thing - I'm not sure what that is - could you please clarify?

quote: Originally posted by clint78z: TimZ I though the base fuel consisted of setting IOT, TOG, then a VE table to make base fuel calculations. Then there is TPS and Map change enrichment on top of that. Could you briefly describe how you set up a fuel map on a Tec II. What you said is correct. I consider the 'base fuel' settings to be IOT and TOG. The VE table is for fine tuning. IOT and TOG define the basic relationship between manifold pressure (i.e., load) and injector pulsewidth. This just defines a simple straight line relationship between the two, and is basically what you would get if you had 100% volumetric efficiency across the engine's operating range. The VE table then represents how the mixture should be 'tweaked' for the characteristics of the individual engine, and is given in percentage richer or leaner than 100% VE. What is nice about this approach is that the values are normalized - in other words, since you are entering values in percent rich or lean, you don't have to figure out the exact pulsewidth that is required for each cell. The TEC does that for you. Brad, my original point on the TEC is that people almost universally say that it's 'too hard' to use, or 'too complicated'. My contention is that it's really about the same as most of it's usual competition. As far as the Holley unit goes, I just downloaded it's manual and it does look really good, and I agree that the increased resolution is a good thing. But, if you think the TEC has too many features...

I'm getting around 15-18" at 900rpm idle lately. I'd have to agree with SleeperZ in that it sounds more like pumping losses from the cam or cam timing. At idle, there isn't always a direct relationship between manifold pressure and idle RPM. For instance, I normally pull a higher vacuum at a fast idle than I do after the car is warmed up. That said, if you want to check for a vacuum leak, try spraying carb or brake cleaner around suspected leak areas. If there is a leak, the cleaner fluid will get sucked in, and the engine should start to stumble. This is a pretty effective way to pinpoint vacuum leaks.

quote: Originally posted by BLKMGK: DFI is still down so far as number of channels but their data rate is 100mhz IF this is right. ...I think you mean 100Hz, right? (BIG difference )

quote: Originally posted by clint78z: TecII is very powerful with excellent datalogging. A slick piece if you have been tuning EFI for a long time. It is very hard to learn there are 3 settings alone just to set up the base fuel map. Software is expensive. Very precise timing control, a little overkill if you ask me. The base fuel map needs two points, not three. Even if it was three, how much simpler does it need to be? We are down to 'idle jet', 'main jet' in the non-EFI equivalents here. I just don't see how this is a major concern. As far as the other required settings, as I have stated NUMEROUS times before (frustration setting in), the basic settings needed to make the cars run are fairly similar across the board. What is it really that makes everyone think that this is harder to learn? Admittedly, I don't have tons of experience with the other systems, but I have yet to see anything that makes me beleive that the others are appreciably easier. A good argument for the more precise timing control is that it allows much better control when the engine is changing speeds rapidly (as high power engines tend to do ). As far as the WinTEC software being better of worse than the the DOS based stuff, I haven't actually seen any credible evidence one way or the other. Of the people that are actually using it, I have not seen alot of evidence to support this. As far as I'm concerned, the jury is still out on this one. I am currently getting ready to convert over to the WinTEC2 chip, and will report back if I find problems. I will say that I'm not terribly impressed with the Windows software, but my main complaint so far is that it's useability is not as much better as I would expect when going from the DOS-based software to the Windows environment.

quote: Originally posted by D83ZXT: What throttle body is that? And may I ask where did you plumb your IAC? The throttle is one of the original Weber 'Big Throat' throttle bodies. It has a 60mm bore. On this throttle body, there was a fixture that looked like it must have been intended to house an IAC of some sort. It was cast into the TB, but it did not have any opeings into the TB. I had the adapter that came with the IAC, which had a threaded fitting on the side, and a hose barb on the bottom. I then drilled out an opening in the TB from the 'IAC mount' to the non-vacuum side (front) of the throttle plate. Once I had the opening drilled out, I epoxied the adapter onto the IAC mount (could have had it welded, but epoxy seems to be working fine, so far) with the hose end part of the adapter using the new opening in the TB to breathe. I then plumbed some -8 hose from the threaded fitting to a fitting on the manifold where the cold start valve used to be. If you look at the picture, this is the hose above the TB that makes a 90 degree turn. Hopefully it makes a bit more sense, now... If you don't have a mounting point like this on your TB, you could just as easily fab a similar mounting point for it anywhere on the pipe that goes from the IC to the TB. [ September 13, 2001: Message edited by: TimZ ]

That was the plan...

You should be able to get rid of that stuff, but you will need to find a way to mount the IAC. Here's a pic of how I plumbed mine: [ September 11, 2001: Message edited by: TimZ ]

quote: Originally posted by 240Z Turbo: BTW, I am a bit confused on how the larger wastegate can increase spool times! The theory is that you would use a smaller than normal turbine housing for fast spool, and then use the large wastegate to control the boost and keep the exhaust backpressure down. The idea is small turbine, without the backpressure under boost. I'm sure this works better than small turbine/small wastegate, but my gut feel is that for ultimate power, you'd probably still want to go with a larger turbine. It's probably a good compromise, though.

I'm not convinced that two turbos will necessarily spool any faster than a properly sized single. As has already been noted, even though there is less rotational inertia, there is also half the flow to each. You might be able to get a bit less backpressure with the twin setup, but that will very heavily depend on your selection of turbos. Also, as somebody already noted, if you can't get enough flow from a single, then you would need to go to twins. this, however, is doubful, unless you are targeting more than 1000hp. Probably the biggest reason to go with the twin setup on a V engine in general is packaging and exhaust routing. This is usually easier, since you can keep the plumbing to the turbos short (usually mounted directly on the manifold), and don't have to deal with some sort of crossover tube. Now, on a V8 Z, the packaging argument might lean back towards a single, since there might not be enough clearance to the frame rails to allow a traditionally packaged twin setup. It might actually be easier to package a single, similar to the mounting on the GN engine. [ September 09, 2001: Message edited by: TimZ ]

Here's a thought... The flapper meter was used in lots and lots of vehicles through the eighties. Take a trip through the junkyards and see if you can find one with a larger diameter bore. Maybe one of the big BMWs or something. This would give you greater airflow for the same AFM reading, which is just what you need. You may have to swap the electronic 'guts' from your old meter to remain compatible, but this might give you the extra range that you are looking for.

Thanks, guys. It looks like that's what I'll do. I was hoping to be able to remove the halfshafts before dropping the diff, but I don't see any way to get any tools in with the proper leverage to do this. Looks like I'm stuck with removing the a-arms and then dropping the whole assembly. Then I can get to it to remove the shafts properly.