thehelix112

GunnerRod, So? Still ambiguous to me. Or don't auto's shift from 1st to 2nd? Maybe I was confused by the language.. `shifts hard from first to second' vs `is hard to shift from first to second' Dave

I'm assuming its an auto then? Thats kind of important to the discussion. Next, what is the car used for? Street/track? Is the engine more powerful than stock so likely to be stressing the transmission? If you want it to go back to stock I recommend you try the genuine Nissan oil, or at least ask your Nissan dealer what they recommend. If you are worried about the gearbox holding together I would recommend redline stuff. Their shockproof manual box oils have a great reputation (and have held my standard 5-speed together behind my turbo box thus far - keeping my fingers crossed), and the ATF oils are fully synthetic to don't mind a bit of heat while racing. Dave

sjcurtis, I'd be keen to see these demonstrations you were shown? Or atleast a description thereof? I will be going full urethane in the rear, but my car is more track orientated. For a street car I can't see it making half a lick of difference either way. Dave

Gaz, Err.. king springs are yellow dude. Mine are. I have POS gabriel shocks in mine, just because I had them sitting there and the existing ones were 100% fooked. King springs also make standard ride height springs for the 240Z I believe. Roll-centre adjusters/bump-steer spacers are designed to return the control arms to their original angle, and hence return the roll-centre back to its original place. I haven't done this as yet. When you lower the car without doing this though the roll-centres will be moving downwards, which means that the distance from the roll-centre to the centre of gravity will be increasing, which means that as you corner you get more body roll as the weight transfer as the centre of gravity acts about the roll-centre to create a moment (torque). The bigger the distance between the roll-cetnre and CoG the larger this torque will be. This can hence be counteracted by adjustable sway bars (which I did do). Mrdatto, No trouble with bottoming out/reduced travel that I know of. Sorry no pic atm, still tuning the mongrel. Aussie260z, Sounds good, though I seriously doubt you will be adjusting the thickness of the sway bar. How much are these bump-steer spacers? Are they just for the front? How thick are they? Dave

chickenwafer, As datto-zed has said, there is not WAY it will be more efficient than either a turbo or supercharger system (has SFA incommon with a turbo system so we'll leave that alone). As datto-zed is hinting towards, by adding more energy conversions between the engine and the compressor you are only loosing more energy. You will get losses driving the water, and more losses in the water driving the turbine. Pointless. DattoZed, Care to explain the rootes generalisations comment? You are aware that jimmy blowers (as seen on 5 second drag cars) are roots yes? (52psi boost and I can't see them having a problem with top-end). They are however, the least adaibaticly efficient compressor of the three. And I find it funny you mention roasting the air as a problem with roots but then say that twin-screws will do it too, (to a lesser degree I admit), but that its not a problem. You obviously are a fan of the twin-screw type. Personally I'd like to see a centrifugal compressor with a CVT drive. Dave

Good job. How do you find the ratios in the 280zx box? I *think* I had a 280zx box in my 240z and I always noticed the 2nd to 3rd change was a killer. I've since replaced it with a 240z but and things seem much nicer. Dave

Aussie260z, As jmanz said the 240 and 260 share the same bits, in fact they are both termed the S30 chassis they share so many. King springs make lowered springs for the rear and lowered progressive springs for the front. I just installed these on my zed and I'm much happier with how it sits. It lowered the car a good 2" I'd say, the wheels fill the guards nicely at the moment. It looks almost factory, and doesn't attract unwanted cop attention which is also good. And for a few hundred bucks you can't go too far wrong. While you're under there you may as well do the shocks as well (ATF the standard ones if the seals are in good nick or perhaps new inserts), and maybe even consider adjustable sway bars to give yourself something else to play with. Dave Dave

Oh and while we're getting back on track, here is some pics of my old (very basic) setup. Note I just brought this as a kit so I take no credit/responsibility: I must admit instant throttle response was nice, but the engine never really got cooking til above 3000 anyway, which is why I made the decision to go turbocharged. Dave

Good point. Sorry everyone, I didn't mean to add to the side-trackedness. My apologies, and some more apologies if I came across angsty.. (I just went for a blast in my car, 150-190 through moderate twisties so I'm feel very mellow atm. ) Take it easy guys, Dave

While we're referring to past responses, I will reiterate mine. You can't make blanket statements based on a poorly designed setup. Yes I do know that they are all like that to a degree, but so what? When the degree drops to close to zero, that does it matter? I don't really see that your RB20 with incorrectly matched turbo example is in any way more pertinent to the majority of z-car owners than my L28 with slightly oversized turbo example. Basically, (and if we can be bothered I'll elaborate) a turbocharger is the easiest way to make a certain power level. I'll be back after I've done some datalogging and 14psi runs with some info for you.

I don't want a drive of a small capacity large/incorrectly turbo'd car that doesn't have the rev range to have a usable power band. The HT18 is a S5 RX7 turbocharger is it not? In which case the turbine housing is WAY too big for the RB20 (as you say) and is the reason its such a pig. $50 at a turbo place would've brought you a VG30DET housing which bolts on and solves that problem. Doesn't sound like fun to me. Noone likes lag, my point was that its not the unsolvable problem people make out. I'm still having trouble believing the two second lag @ 5000rpm thing. Maybe it felt like 2 seconds? Or do you have a datalog to prove otherwise? Perhaps I'm not getting it entirely, or maybe its both of us, but my point was that in a well-setup turbo car power IS there when you want it. A turbo car only has lag while the turbine is accellerating, when it is up to an appropriate speed there is no torque rush, there is no lag, and throttle response is comparable to a N/A engine. Have you ever driven your car long at moderate RPM, very light throttle and heard the BOV venting constantly? My engine does this at between 3500 and 4000. So lets be pessimistic and say its 4000, that means if I'm going round a corner at 4000 I have perfect throttle response, exactly the same as I would if I didn't have a turbo at all, and I can feather it all I want. Of course turbo cars add another complication and this makes them harder to drive, but who doesn't love a challenge? Dave

Ken, wow. More points: 1. Cheers for the patronising. 2. I might point out that I wasn't the one to raise turbochargers, which I believe occurred on the 4th reply to the thread. 3. If I have posted wrong quotes and incorrect information, please feel free to point them out to me. Everything I saw is for the purposes of education: I say something that I think, its discussed and if a valid argument against it is raised I then take that on board. I am not here to have a pissing competition. 4. I'll continue along the lines I started as I don't see anything wrong with them. Cool. I can understand the advantage of controlling variables and changing things one at a time. I also acknowledge that when you said boost levels in most cases wouldn't REQUIRE an intercooler is quite possibly true. If you are not doing it for R&D purposes though, I can't think of a good reason not to run one. Good point, I misread what you wrote on that one. Apologies. Well as I've never tuned a by-passed supercharger I won't comment further. The only two points I'd made before this were in the first case, just a rehash of another's experiences that I thought might be of interest to some people, and in the second case, a very obvious observation about efficiency. Maybe if you hadn't taken offence you'd've seen that? Fair enough. As I said, horses for courses. Though if you are doing what you said in the first bit of this you aren't exactly driving it well. I would say that any car takes a little while to adjust to, in my case at least. And I still believe its not that difficult to drive well above the RPM at which lag becomes absolutely minimal in a well setup turbocharged car The same could be said for turbocharging, and in having a ride in a proper turbocharged car. Why? We're just talking. Isn't the whole point to discuss things like this? Or have I `ruined' the nice little back-patting session you had going on? Dave

I disagree. Looking at the vid, there is a significant amount of time that boost is 21psi and exhaust is constant at 14.7. As the flow/rpm goes up the exhaust pressure then fluctuates between 14.7 and 30psi. This is almost exactly 1:1 if you take the average, and only 1.5:1 when you take the absolute peak. Streetable is up for consideration in the next point. No arguments regarding terminology (see I used both in my last post). Can't argue there.. sounds standard fare for a short stroke low displacement engine. 2 seconds is ridiculous if you are going by your previous indicated 5000rpm example. Errr.. not really. You just can't make a blanket statement about all turbo's like that. That is EXACTLY what frustrates me. How many turbocharged cars have you driven in anger? Have you been in one that was a decent quality build? If you are building a good quality turbocharged engine you take into account approximate boost threshold and ensure that the engine has a usable power band above this. If you have 2 seconds lag at 5000 (which to be honest I don't believe at all) the engine is already what? 6500-7000 in that time and just about out of revs. That makes it rather unusable, and not a good basis on which to judge every turbocharged car ever built. BTW, what is this large turbo on the RB20 you speak of? I haven't been in too many turbo cars, and I've only driven one in moderate anger through corners (my L28 with GT35R) and its simply a non issue. At 3500 you simply feed the power on as you exit as per a normal engine. Obviously lag will never be zero so perhaps you start to feed it on slightly sooner than you would otherwise but its still perfectly drivable. Haha.. I personally don't understand peoples preoccupation with throttle response, as I said, the only drivers I can see who require it are rally drivers. If you're going round a circuit then you know exactly whats coming up and can select what gear is required to get lag down to an absolute minimum. I will screenshot some of the datalogs of my turbo engine so you can see how long it takes to come on boost from different RPMS after you plant it. That should give us some points for discussion. Dave

Holy moly, I turn my back for a couple of days and look what happens. A few points: The typical applications you are talking about are stock applications where they are designed to drive like naturally aspirated cars (very low boost threshold and next to no lag). With a properly matched turbo and exhaust manifold the pressure ratio between inlet and exhaust drops to more like 1:1 and below. Check out http://pforums.company-hosting.com/forums/showthread.php?t=67189028 with a video. Notice that as the turbo comes on boost it gets to 21psi intake while the exhaust manifold pressure is still around 100kpa (14.7psi). That will be flowing more through the chamber than a naturally aspirated engine which can only ever hope to get to 1:1 (or slightly beyond momentarily). The obvious tradeoff is low-end torque and lag. Are you kidding? I wouldn't be running anything over 7psi without an intercooler. And why wouldn't you use one? Its free power, it makes detonation less likely, etc. Especially considering positive displacement superchargers have horrid adaibatic efficiency compared to centrifugal compressors. How does an external bypass dump more air on throttle close than an internal one? especially as the internal one has no alternate route, but the external one does. Tuning accelleration enrichments depends a lot on the engine management. It was very tricky using a megasquirt, and very easy using an autronic. Good datalogging (AFR, MAP, RPM, TPS) make this no more difficult than any other part of tuning the car. I was running my 240Z with a L28 supercharged using a toyota SC14 (1GGZE) supercharger. This supercharger is WAY too small for the engine so only gave me 5psi. There are so many factors to consider when you are trying to decide about the viability of superchargers for your application: - power output - power delivery - packaging options (phsyically mounting the bits) In reality, you will be able to get basically whatever power you want from either a turbo or a supercharger setup with enough development. Horses for courses. Oh and my final thought (just because this point annoys me something fierce), turbo-lag is a storm-in-a-teacup for street/circuit driving (only people who require instant response in rapid on-off applications are rally drivers). Seriously, grab the next gear down ffs! Gone! Dave

Is it an auto? Dave

Are you guys going to add links here to the ebay ads when they go up? Dave

`` Q: can you tell me if that would fit a 4.5l petrol patrol motor. A: yes as far as i know '' Hmmmmmm... I'd like to see pics of the exhaust manifold. Dave

Why settle at three? Nick yourself a quad-rotor. 2.6L. Personally I detest the sound of rotaries. I appreciate them from an engineering point of view and am in awe of the power they make, but I know I would get a shock going from the reliable L to a rotary. `What?! It blew up AGAIN?!' Dave

Jason, Just ensure you've got some revs when you push the gas and you will have power with a turbo or without. Long live the L!. Dave

Dave, I agree this is a debate that will never be solved. Not to worry, different strokes for different folks. I'll stick with my turbo engines I think, though I do appreciate a screamer N/A engine. Dave

People make such a huge deal out of the lag issue with turbo cars. I personally don't know what the fuss is all about. I've driven a 3.0L SOHC turbo holden commodore (RB30ET) which started to make boost at 4000 and ran out of revs at 5500 and it wasn't that hard to drive quickly around a track. Just peg a lower gear coming into the corner. If you're really keen/talented (which I'm not) you can also hop back on the throttle while leaving the brake on through the apex to spool the turbo. I'm not sure what you mean by `odd areas of the powerband'. FWIW my L28ET with a garrett GT35R (ie, 640hp capable turbocharger) makes positive manifold pressure at 3000rpm. How often do you see below 3000rpm if you're driving quickly anyway? Obviously a more moderate turbocharger would see boost even earlier. Interesting way to put it, but I agree anyway. A turbo car will be more expensive simple because there are more bits you need. Intercooler, turbocharger, wastegate being amongst the most expensive. Go240Zags, I'm not sure how hard L28ET exhaust manifolds are to chase up up there or what other parts you require for your L28E to run turbocharged but I can't speak highly enough of a turbo L. Your F54/P90 with dished pistons is running a very low compression ratio (7.38:1) which in a 240Z still gives quite reasonable drivability off-boost. I've only driven mine on 5psi thus far (ie, less than stock) and boy its a rush. As I said, makes boost by 3000, 5psi shortly thereafter and just doesn't stop. However, all the other costs associated with getting the L28E into the zed might be prohibitive, namely, fuel injection issues: lift pump, surge tank, high pressure pump. So you have to weigh this up against the work involved in raising the compressino of the F54/P90 engine to work in a N/A application. I would happily swap you a high compression L28 for your low compression one. F54/P90 L28s are like hens teeth over here. Dave

Another vote for the K&N filter. I also just started using redline race oil 40wt. Yet to drive it too much to make any comments but it seems to work. Dave

few points 1) The compressor is the side that is not attached to the exhaust, ie, the shiny side in the pics, or `the cold side'. 2) The turbine is the other side. The turbine extracts energy from the exhaust gas flow and transfers it down the shaft to the compressor. 3) The compressor's trim is 57. This implies I believe that he is using a TO4E 57 trim compressor wheel (as opposed to the TO4B series of compressor wheels) compressor map is there: http://www.turbofast.com.au/FlowTO4E.html Looking at this graph you can see that the absolute maximum boost pressure this turbo will flow is 2.2 bar (32psi). However, it will flow enough air to make around 370hp (37lb/min) at that boost pressure. At lower boost, say, 1.5 bar (22psi) it will flow enough to make its full potential of around 440hp (44lb/min). This turbo would go great on any L6 combination, as Dave mentioned, aslong as you have the support systems capable of driving it. As Dave says, give us more details for more answers/opinions. Dave

Ahhh.. the s on the end. Stupid me and stupid google. Will do, Dave