TimZ

katman is on the money with this post. Coordinating the coil bind height/spring free travel with the available strut travel is critical to properly setting up a coilover suspension. Lack of attention to these details is precisely what gives coilover suspensions the reputation of being "bouncy" on many forums. Eibach's 8", 225lb/in, 2.5"id spring has 5.29" of free travel before coil bind (other brands will be very similar), so the 5" number that katman quoted is pretty much all the travel that is available with that spring. It's also worth noting that this spring gives up ~2" of the available strut travel no matter what you do. The best placement of this spring (centered on the available travel) would result in an approximate 1" drop, assuming unmodified struts. Dropping an additional inch would only leave you with about 1.5" of available travel - which would leave you riding on the bump stops pretty much all the time. Not good. Another problem that you can run into when trying to go to a stiffer spring to keep from bottoming out is that you lose droop travel - basically your droop travel becomes only the amount that the spring gets compressed at the static ride height. In Pete's case, there is only about 2" of droop travel available, no matter what he does. So, any bump that causes a rise of more than 2" causes the tire to leave the ground. I do use a coilover setup on my rear suspension, but I opted to use a longer spring that was capable of utilizing the full travel of the suspension. I had to give up about 0.5" of wheel clearance to do this, but it does still give more clearance than the stock spring. With this setup I was still able to fit a 245/45-16 under the stock wheel wells with a small amount of trimming. My struts don't bottom out, and my tires don't leave the ground on bumps. 255's would not have fit.

On the 'old suspension design' aspect, while the Camaro does have an SLA front suspension, it still has a solid rear axle. Even with the four link, I doubt that it is superior to Chapman struts for handling purposes. One other thing to consider - the BMW 5 series still uses pretty much exactly the same suspension configuration as the Z. I seriously doubt that the Camaro handles better than the 5 series, or that anyone uses this as an argument to decide between the 5 series and a Camaro . It's all in the development.

im not sure I understand this. I am under the impression that this figure would depend on the bore size of the combustion chamber. I wouldent think there would be a fixed number for all heads. also what is the difference between the alum head and the iron head. I see size as being size and I cant figure out how the material would matter. I have a feeling you were waiting for me to ask this though so please inlighten me if you can. Head material has nothing to do with how much the chamber volume is reduced. As you suspected, it has everything to do with the shape of the combustion chamber. For an open chamber head, the amount is fairly close to the area of the bore times the amount that was shaved. In the case of an 87mm bore, the number works out to about 0.75cc per 0.005". For a closed chamber head the number will be considerably less - probably about half to two-thirds that amount. For open chamber heads, the 1cc/0.005" rule of thumb is fairly close, simply because most piston engines are in the same ballpark (+/- 50%) as far as bore size goes. Spiirit - What's the story with that avatar? It's making me all sad...

I wasn't knocking your products at all. I was trying to make the point that many of the "kits" out there require just as much (if not more) work as your adapters will.

Guess again. MANY items that I have bought as a "kit" required major modification/fabrication to get them to work properly - including my AZ ZCar brakes - ESPECIALLY my AZ ZCar brakes (I would have bought something else, but this was several years ago, and AZ ZCar was the only game in town). I've pretty much given up on "kits" altogether for the Z, or at least on believing that if I get a "kit" it will all fit on the first try.

Glad that worked out. The MAP sensor ground makes perfect sense - you were most likely getting some signal out of the MAP with just the power and signal connections which maybe looked sensible. But when the starter kicked in, without a solid ground reference the MAP signal probably shifted abruptly. The TEC probably thought it was seeing a really high MAP pressure, and tried to compensate.

Aside from still being too large, -5 is kind of an oddball size. You'd be very hard pressed to find any kind of adaptors for it.

For the same price? Doubtful. NOTHING on a Supra is cheap.

First off, I would go and check all of the wiring connections at the stupid green connectors - one or more of these could have pulled loose from moving the harness around. This really sounds like a ground shift problem being introduced by the high current draw of the starter.

So let me get this straight - did the car start and run properly before moving the TEC? No wiring change whatsoever? Not even ground connections? No calibration changes before this started?

Is everything else the same between the two, as in identical? A 7% increase in displacement should only require about 1psi of additional boost in the 2.8. Maybe 2psi, but 4-5 sounds excessive.

The horsepower and torque scales are different. The lines cross numerically at 5252, like they are supposed to. The rules of thumb stated for injector sizing are based on a Brake Specific Fuel Consumption of 0.5 lb/hr/hp. The BSFC can vary from about 0.4 to about 0.6 depending on the engine. Also, the 80% rule has nothing to do with how much power the injector can ultimately support - it is there to tell how much headroom you should leave yourself when sizing injectors so that you won't go static. The injector should still flow it's rated amount at 100% duty cycle, you just no longer have any control over it. Notice the flat horsepower curve from about 5500rpm on up - there is a very good chance that the injectors had gone static there. The fuel pressure numbers don't quite make sense to me - I am basing my assumptions on 57psi at 7950rpm and previously stated 18.3 psi boost, which gives a base pressure of 38.7 psi. This jives reasonably well with the 38psi number given for idle, assuming he really meant 0 vacuum and not idle. Anyway, since injectors are rated for flow at 43.5psi, running a base pressure of 38psi derates them by about 7%, meaning they would have been performing like 520cc injectors. If the comments in this thread offend you, well - sorry, but you should realize that there are boatloads of bullshit hp claims floating about these days (probably always have been - the internet just makes it more evident), and if you offer up really big numbers to a reasonably educated audience and the details look funny, you are going to get challenged.

Bump.

While an intercooler isn't absolutely necessary at low boost pressures, it should still be beneficial, due to the lower intake air temps it will allow. You should be seeing a horsepower gain from it even at 5psi.

It's a bit of work, but not that bad, since it sounds like you are going to end up pulling the springs out anyway... What I would recommend is to first take a repeatable measurement with the suspension settled on a flat level surface and at your current ride height. Fender lip to wheel lip should work. Now, put the car on jack stands, disassemble the suspension, pull the spring out and reassemble it (it's not so bad - it's pretty easy to assemble without the spring). Use a floor jack to jack the suspension back up to the point where it was in the previous measurement (your current ride height). Now slowly continue jacking the suspension up until you start to lift the car (i.e. the suspension has bottomed). If you now repeat the first measurement (e.g., fender lip to wheel lip) and subtract the new number from the first measurement, you will have measured the amount of bump travel that you have before bottoming out.

To be fair, 70kph is only about 42mph - it's not that horribly fast. I'm still waiting for answer to my questions - my money is on the bump stops.

Just thought I'd dredge this subject up again (reposting from another thread...) I'm currently reassembling my engine, and upon inspection it looks like my damper might be starting to seperate - there are some circumferential cracks visible in the rubber - they don't go all the way around (yet), and I have no way of telling just how deep they go. Needless to say, though - it's enough that I don't want to re-use this part any more. So JeffP - is the BHJ part ready for prime time? I checked their web page and didn't find a part referenced for the L-series.

Just thought I'd dredge this subject up again I'm currently reassembling my engine, and upon inspection it looks like my damper might be starting to seperate - there are some circumferential cracks visible in the rubber - they don't go all the way around (yet), and I have no way of telling just how deep they go. Needless to say, though - it's enough that I don't want to re-use this part any more. So JeffP - is the BHJ part ready for prime time? I checked their web page and didn't find a part referenced for the L-series.

Simon - I have a couple of additional questions - how far did these springs lower the car, and were any other mods made, such as shortening the struts to regain lost suspension travel? If you lowered the car by 2.5" or more with doing anything about suspension travel, you are most likely hitting the bump stops (you do have bump stops, right?), which can cause all kinds of funkiness.

Ummm - voice of sanity here... With all the trouble you are going to go through trying to get the 240sx pistons to work, you could probably come really close to paying for a set of forged pistons, made to the proper deck height. Then you could avoid all the silliness of compensating for chain slack, cam timing, re-boring holes for oil restrictors, etc. AND you'd have a much nicer set of nearly indestructable pistons. Also, with -1.37mm deck height, you might be able to get the compression back up by milling the head, but all of the supposed advantages of the closed chamber P-series head design will be negated, essentially making it an open chamber head with a bunch of exposed sharp edges.

To be fair I did just notice that I misread Tim240z's statement - I thought he was saying that the strut bar would twist. I see now that he was saying that the strut bar could not stop the strut towers from twisting because of the rod ends (I think?) My bad. I still stand by the rest of what I said, though - the strut bar should not try to keep the towers from twisting - it couldn't do an effective job of this if it was solid, anyway. As I said, it has no strength in this direction.

There was a rather lengthy discussion on crankshaft dampers and harmonics in this thread: http://www.hybridz.org/phpBB2/viewtopic.php?t=18731&postdays=0&postorder=asc&start=0 This link was referenced in that thread, and is a very good reference: http://www.dinanbmw.com/html/danger_of_power_pulleys.htm