mdelorie Posted June 7, 2007 Report Share Posted June 7, 2007 This question might be more suitable over at the 60-degree forums, but I figured I'd see what kind of info I could stir up here first: I'm considering building up a turbo engine to put into my Lumina. My main goal is efficiency, with fuel economy and power being the primary factors (a terrible thing to want both of, but that's why I'm going the turbo route). Any suggestions on which engine would be the best candidate for this? I'm thinking probably a 3400, but, I'm no engine pro. Quote Link to comment Share on other sites More sharing options...
AWeb80 Posted June 7, 2007 Report Share Posted June 7, 2007 if i'd do it, run a 3400 w/ port and polished heads/intakes to help w/ flow and run maybe 7-10 psi w/ a good tune so you can run 91..possibly 89 depending on how good the tune is w/ OBD II..... port/polish/gasket match will help w/ efficiency. i'd guess you'd be around 220-240 whp....i could be low though...i'm not sure on numbers. Quote Link to comment Share on other sites More sharing options...
mdelorie Posted June 7, 2007 Author Report Share Posted June 7, 2007 Okay, let's say I'm a cheap bastard and want to run 87..... Also, is there such a technology that will dynamically adjust the amount of boost being delivered based on the octane of the fuel you're running? Quote Link to comment Share on other sites More sharing options...
slick Posted June 8, 2007 Report Share Posted June 8, 2007 Do a 3400 with 3500 intakes. Yes, you could tune to run on 87, but your not gonna run it to it's fullest. Meaning, it's not gonna run as efficient as it possibly could. Thermodynamically, your gonna get greater efficiency running a high compression engine over a turbocharged engine (ok, my thermo 2 class is getting to me, but engines are just a humgongous thermodynamic cycle, and the 4 stroke gas engines are some of the worst in efficiency). Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted June 8, 2007 Report Share Posted June 8, 2007 bored 3400 with 3500 heads and intakes. In order to run 87 with a turbo'ed engine your compression has to be sooooo low. around 9:1 is just about where you would want it for the street and pump gas. Slick. high compression engines make just about as much heat as turbo'ed engine. High compression engines have cylinder pressures around 200psi ( depending on compression ) but then again whats your definition of high compression? Im talking about to the point of running leaded fuel, around 11.5:1 and above. Quote Link to comment Share on other sites More sharing options...
slick Posted June 8, 2007 Report Share Posted June 8, 2007 Slick. high compression engines make just about as much heat as turbo'ed engine. High compression engines have cylinder pressures around 200psi ( depending on compression ) but then again whats your definition of high compression? Im talking about to the point of running leaded fuel, around 11.5:1 and above. 11.5:1, 91-93 octane. I'm just talking from a thermodynamic standpoint that they run more efficient(pressures, temps, but/cycle, etc...). I don't have the file on me, but I could send you an Excel spreadsheet, if you would like, that go's through the thermo cycle. You can then adjust the engine size, compression, rpm, etc... It will give your efficiency, hp to keep it going at that rpm and speed, etc... The spreadsheet that I created(according to my thermo book) shows that you really only increase HP from boost, but your efficiecy will increase with higher compressions. If your interested, lemme know! Quote Link to comment Share on other sites More sharing options...
slick Posted June 8, 2007 Report Share Posted June 8, 2007 BTW, I will admit that I have personally heard of people getting better mpg with boost, so obviously the spreadsheet isn't 100% perfect (doesn't factor in the trans, vehicle weight, tuning, etc...). Quote Link to comment Share on other sites More sharing options...
mdelorie Posted June 8, 2007 Author Report Share Posted June 8, 2007 Sure, send away to my listed email address. Quote Link to comment Share on other sites More sharing options...
PCGUY112887 Posted June 8, 2007 Report Share Posted June 8, 2007 I would just use a nice 3400, maybe some gasket matching... otherwise with all of the costs of a top end swap and such, plus the cost to get the turbo running the way you want it... well you'll be paying way too much. Quote Link to comment Share on other sites More sharing options...
pwmin Posted June 8, 2007 Report Share Posted June 8, 2007 L67 swap would be the easiest imo. if you do exhaust, intake, and rockers and tune it (mostly more cruising timing), you should be able to get close to 35 mpg Quote Link to comment Share on other sites More sharing options...
mdelorie Posted June 8, 2007 Author Report Share Posted June 8, 2007 Maybe so... but I want a turbo, bottom line Quote Link to comment Share on other sites More sharing options...
digitaloutsider Posted June 8, 2007 Report Share Posted June 8, 2007 Okay, let's say I'm a cheap bastard and want to run 87..... Then you don't need to be doing a turbo install. Quote Link to comment Share on other sites More sharing options...
pwmin Posted June 8, 2007 Report Share Posted June 8, 2007 yeah id say you shouldnt have a turbo then. the gen V M90's are actually designed to be able to run on 87 Quote Link to comment Share on other sites More sharing options...
mdelorie Posted June 8, 2007 Author Report Share Posted June 8, 2007 I may be oversimplifying this in my mind, but I would think that a dynamic boost adjustment system wouldn't be too difficult (at least in concept - finding one or engineering one might be an entirely different problem.) If you're running 87, and the boost is too high, the knock sensor detects detonation and backs off the boost via the wastegate. Run higher octane fuel, and the wastegate doesn't need to open too much. Does that make any sense? At least even in theory? Quote Link to comment Share on other sites More sharing options...
crazyd Posted June 11, 2007 Report Share Posted June 11, 2007 Okay, let's say I'm a cheap bastard and want to run 87..... Also, is there such a technology that will dynamically adjust the amount of boost being delivered based on the octane of the fuel you're running? Yes, it's called a knock sensor. -D Quote Link to comment Share on other sites More sharing options...
pwmin Posted June 12, 2007 Report Share Posted June 12, 2007 you dont wanna rely on your knock sensors for that. if the knock sensors are retarding too much timing, you should find a way to reduce it. you dont wanna run off the bad fuel table. its better to do it right. Quote Link to comment Share on other sites More sharing options...
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