WizardBlack Posted April 25, 2009 Share Posted April 25, 2009 I'm getting bored with realistic goals. I read the whole tech thread on the garrett website to figure out how to map out a turbo. The only thing they didn't mention is how to map a dual setup. I assume that the flow rate would be half of the total for each, while the pressure ratio would have to be the same. I'm not sure if it works exactly like that in real life though. I plugged in 500hp just for fun, and it comes out to 24psi of boost, meaning 64lb/min flow @ 3.0 PR total. What I don't get is their equations don't seem to account for the engine configuration. I mean there's obviously much more to it than displacement, as illustrated by the fact that stony probably has twice the power with the same engine I suppose that you can look at it like modifying the engine other than displacement or compression increases the VE and stuff like that, which is included in the garrett formulas. I put in estimated BSFC and stuff like that too, but there are so many factors it is hard to see how each one affects the outcome. That aside, I browsed their midsize turbo list and found this one to be pretty ideal (it's acually the only one within operating limits), aside from making a hybrid or something. I haven't figured out how to guestimate the lower revs yet based on what boost is below peak hp. I didn't even realize until after that this one says direct replacement for skyline, along with 8 other models. There is also a larger turbine option, but it doesn't have an accompanying map. A pointless endeavor I know, but a fun one nonetheless. Mapping to the engine is up to you, but that's where the hot side comes into play. You are basically correct on your assumptions about PR the same and flowrate divided in half if you choose to employ two turbos. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted May 13, 2009 Author Share Posted May 13, 2009 Well if I had cash flow right now, my posts would be less trivial, but just to clarify... The lazer gauge apparently came with the wrong instructions. I called msd and the guy was very helpful, said he owned the same gauge, and yes the cyl count is programable, so I hooked the tach driver back up to the negative on one coil only and set the gauge to 1 cylinder, apparently it comes set to 4 or something, unlike my instructions said (ie. 1 cyl non programmable.). Now I just have to figure out how to fix the needle. I probably won't be able to send it back since I got it on ebay, so I'll have to take it appart and hope it will go back together and work. That is on the assumption it's just dirty or rubbing against the lense, something of that nature, and is fixable. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted May 28, 2009 Author Share Posted May 28, 2009 Part 1: I took off a rear wheel and verified that the distance between the wheel well lip and the shock strut is just over 9" and furthermore the offset of the rim should be .5" to center it just about right. That would make the tires I want to get fit pretty darn snug. The tire width is 9.2" but that should be neither at the base of the spring nor the well lip. However, the suspension might have to be fairly tight to keep the wheel from bottoming out because it would only have a few inches of positive loading. I might be pushing it... Part 2: I drove around at various speeds to test the signal coming out of the speed sensor to determine what would be necessary to convert the tach to a speedo if that is the route I can take. If the range is mainly in voltage, then a frequency controlled oscillator would be needed as the tach input is based on frequency. However, if the output is in frequency, then a simple signal divider can be made, which my teacher says would be simple for him to do once I figured out the ratio. The interesting conclusion is that both the VAC and Hz vary directly with speed, I suppose it should have been expected since the little generator doesn't have any sort of field control unit. Giving it my best approximation, the voltage varies about 14% between 20-65mph however, and the frequency varies only 4%. Of course there is error in my readings, but the Hz seems to be the ticket. Even if my data is dead on, the greatest deviation when the circuit is at the average ratio would be a mere 2mph at 65. I'm not sure how must speedos work, but this would suggest that they are also frequency counters, unless my data is wrong--the voltage reading is too unreliable. I shall remove the sensor and bench test it for a more accurate Hz reading. The only problem is that I don't yet know how fast to spin it for any given speed. The only thing I could do at this point is spin it based on the data I already have, but that would make the new findings just as inacurate. The alternative is to somehow figure out what the gear reduction ratio is between the transmission output and the sensor. Does anyone know what final gear options the skylines came with vs. what pinions on the speed sensor? I might be able to figure out the ratio that way, the match to how many teeth correspond with each diff. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted July 28, 2009 Author Share Posted July 28, 2009 For what it's worth, a tiny update. (I didn't vanish!) I decided to hell with making my own gauge and I got an autometer cobalt speedo.The dakota digital speedo adapter may very well have worked for me, but I was sick of sweating over it and investing more in a silly project. The gauge looks very nice though, and if the tach keeps giving me crap I'll just get the matching cobalt one, and later on three small ones. At any rate it's not such a bad match anyway. The lazer gauge has not been on my good side though so far, strike two msd! Also, not that I have money right now, but if I did, I'd spring for the fiberglass fender flares from the Z store, I recently saw that they had some without the boltholes--non zg style. I think they would look good molded in, and I could use wider tires then that are more worth the money. I'm not sure how much of a step up the ones I was looking at would have been anyway. I still have o2 sensors and fuel injectors on the shopping list, among other things obviously. They should be replaced though at any rate, not so much for upgrading purposes. I could never figure the o2 sensors out, I'm thinking the heaters don't work and one seems to read different than the other. My biggest problem is that I don't know where to get them at reasonable cost, is there any domstic nissan that uses the same ones? The injectors could be to blame for a lean condition though, and rather than get them cleaned I might just spring for bigger ones for the hell of it. There's a small coolant leak that has been boggling me forever and I'm going to get a pressure tester to pinpoint it. At first I thought it was the overflow tube or something, it seemed like it was leaking more when hot and full and subsided when low, but it looks like my imagination because I found it slowly dripping even when parked and it's coming down from somewhere on the end of the core! Seems like the darn thing had a manufacturing defect and there's a pinhole in the weld on the cap, hopefully it will turn out to be something I can get to so I can fix it. Someone owes me a bunch of money and if I ever get it back I'd like to invest in supplies to make the interior panels out of fiberglass, perhaps even sell some sets if people are interested in upgrading. The replacement ones seem to be somewhat cheaply made, and I'd like to modify the design a little anyway (get rid of the fake speaker holes and the bump that was for the emissions can, possibly make the sides a one-piece construction). I'm taking classes on composites anyway so why not put it to good use? Once again, I digress. Cheers! Quote Link to comment Share on other sites More sharing options...
luckygerman Posted July 29, 2009 Share Posted July 29, 2009 Man I just got through reading this thread, what a project it must be. I really enjoy your RB swap, it looks very clean. I hope it is all worth it for ya. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted July 29, 2009 Author Share Posted July 29, 2009 Thanks man. Yeah I'm still pretty excited about it. I haven't even done anything to it yet, but needless to say my imagination is going wild. And even with the horrible suspension and failing interior and no a/c, it's a blast to drive. I got tunes though, So I'm happy for now. sr20 should be pretty intense though, rally? Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted September 28, 2009 Author Share Posted September 28, 2009 Yeah apparently MSD is NOT the company to trust for making gauges. This one too is still giving me all sorts of hell. It seems like the memory kept dumping because it resets the shift light and cylinder count every once in a while and would even go through the demo mode sometimes. Now if I reprogram it, the memory lasts like ten seconds and dumps again, so basically I'm chucking it and getting the autometer cobalt tach to go with the speedo. At any rate, it looks pretty sexy. To keep myself busy for now I bought some window louvers for 50 bucks and am rebuilding them. Painting them flat black with a rattle can is proving to be a challenge especially into the santa ana winds, but they're almost done. I'm taking pictures just for the hell of it. Quote Link to comment Share on other sites More sharing options...
Careless Posted September 28, 2009 Share Posted September 28, 2009 Yeah apparently MSD is NOT the company to trust for making gauges. This one too is still giving me all sorts of hell. It seems like the memory kept dumping because it resets the shift light and cylinder count every once in a while and would even go through the demo mode sometimes. Now if I reprogram it, the memory lasts like ten seconds and dumps again, so basically I'm chucking it and getting the autometer cobalt tach to go with the speedo. At any rate, it looks pretty sexy. To keep myself busy for now I bought some window louvers for 50 bucks and am rebuilding them. Painting them flat black with a rattle can is proving to be a challenge especially into the santa ana winds, but they're almost done. I'm taking pictures just for the hell of it. before you do that, open the gauge and look for a button-cell battery. batteries of that type have a short shelf-life and usually they're what keeps the power constant to the unit when the car is shut off. replace it and it should hold your data. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted September 29, 2009 Author Share Posted September 29, 2009 It's a dumb battery? I suppose it could have been on the shelf for a long time... I might as well tear it apart since it's otherwise trash, but the thing is glued together something powerful, so we'll see. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted September 29, 2009 Author Share Posted September 29, 2009 Yeah I just took a look at it's guts and definitely no battery. It's probably a cap that holds the memory for short intervals. Either way that doesn't explain why it would lose power while running. Oh well, once i got the speedo in, the lazer tach kinda lost its luster anyways. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted October 6, 2009 Author Share Posted October 6, 2009 Eh, I changed my mind. I don't want to dilute this thread. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted October 7, 2009 Author Share Posted October 7, 2009 I will however dilute it with this. Reading old news can be quite entertaining http://www.automotivehelper.com/topic8063.htm I was looking for a 3.0 stroker and that's the first thing I found. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted November 28, 2009 Author Share Posted November 28, 2009 Ok I finally have a working tach. Sprung for the autometer cobalt that matches my speedo. It doesn't have a 1cyl mode so I moved the msd gmr pickup to a common wire and set it to 6cyl. Seems to work despite the instructions on the pickup saying that with that speed it would read erratically. The only other way to do it I suppose would be to tether the leads from two opposite cylinders and put the tach back into 4cyl mode. Quote Link to comment Share on other sites More sharing options...
Ed260Z Posted March 17, 2010 Share Posted March 17, 2010 You haven't posted in a bit. How's the build going? Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted March 31, 2010 Author Share Posted March 31, 2010 (edited) Hey thanks for the interest. I haven't done much due to being broke and jobless for quite a while now, but I just got hired full time and I start on Monday! So basically you might be seeing some updates soon I might start a new thread on building up the engine, this one is mostly for just the initial install. I have been working on other things though, such as making custom interior parts found here Vendor Forum Tech Forum and related posts about led tail lights here I also started a misc build thread on my little car projects that aren't really engine related found here PS I don't remember if I mentioned the writeup I posted here I feel like I just hijacked my own thread ha! Edited March 31, 2010 by getoffmyinternet Quote Link to comment Share on other sites More sharing options...
Ed260Z Posted March 31, 2010 Share Posted March 31, 2010 Hey thanks for the interest. I haven't done much due to being broke and jobless for quite a while now, but I just got hired full time and I start on Monday! So basically you might be seeing some updates soon Good to hear you'll be starting a new gig. I was in the same situation Dec, and Nov wasn't much better. Just need to catch up on 1 or 2 more debts, and I can finally start my build. Good Luck on Monday. Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted April 1, 2010 Author Share Posted April 1, 2010 OR NOT Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted April 8, 2010 Author Share Posted April 8, 2010 it's back with a vengeance! "And the seat being reclined all the way means the guy overboosted =P. " "My bet is they ditched it after realizing how damn fast it was, sort of an "f- this, too fast" " Quote Link to comment Share on other sites More sharing options...
pat1 Posted April 8, 2010 Share Posted April 8, 2010 You got it back? That's bada$$ man. Is it messed up at all? Quote Link to comment Share on other sites More sharing options...
getoffmyinternet Posted April 8, 2010 Author Share Posted April 8, 2010 Interior is thrashed and it feels like the perp used my car to learn stick, but I'm just glad it's in one piece. Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.