bthomp Posted November 12, 2010 Share Posted November 12, 2010 i know that engine size plays a roll when looking at turbos. but im looking at a GT45 with the specs-Compressor Size: Inlet = 4 3/16", Inducer = 68.7MM, Exducer = 97.8 MM, Trim = 69,A/R = 0.66, Intake (ID / OD) = 2.25" / 3.25" Turbine: Outlet = 4", Turbo flange = T4, Downpipe flange = 3.5" V-band, Inducer = 87.4 MM, Exducer = 77 MM,Trim = 92, A/R = 1.05 would this be too big for the L28 engine to really work? Quote Link to comment Share on other sites More sharing options...
240zip Posted November 12, 2010 Share Posted November 12, 2010 here's a picture showing a GT45 turbo on a RB engine. Too big ... you decide! http://www.gtr.co.uk/forum/107028-r-i-p-s-rb30-gt45-street-engine-ready-testing.html Quote Link to comment Share on other sites More sharing options...
B00STDZ Posted November 12, 2010 Share Posted November 12, 2010 here's a picture showing a GT45 turbo on a RB engine. Too big ... you decide! http://www.gtr.co.uk/forum/107028-r-i-p-s-rb30-gt45-street-engine-ready-testing.html Hahahaha This. Quote Link to comment Share on other sites More sharing options...
S130Z Posted November 12, 2010 Share Posted November 12, 2010 i know that engine size plays a roll when looking at turbos. but im looking at a GT45 with the specs-Compressor Size: Inlet = 4 3/16", Inducer = 68.7MM, Exducer = 97.8 MM, Trim = 69,A/R = 0.66, Intake (ID / OD) = 2.25" / 3.25" Turbine: Outlet = 4", Turbo flange = T4, Downpipe flange = 3.5" V-band, Inducer = 87.4 MM, Exducer = 77 MM,Trim = 92, A/R = 1.05 would this be too big for the L28 engine to really work? A 1.05 a/r turbine is WAAAYYYY too big for our motors. Bigger is not always better. Try a GT30 or GT35 w/ a .63 a/r turbine. My GT30 has a .70 a/r compressor and a .63 a/r turbine. Quote Link to comment Share on other sites More sharing options...
78 LS2 Z Posted November 12, 2010 Share Posted November 12, 2010 If you oversize your turbo from the start, you are hosed....It's always better to be conservative with a smaller turbo- If you are stuck between deciding on two, go with the smaller turbo. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 12, 2010 Share Posted November 12, 2010 A 1.05 a/r turbine is WAAAYYYY too big for our motors. Bigger is not always better. Try a GT30 or GT35 w/ a .63 a/r turbine. My GT30 has a .70 a/r compressor and a .63 a/r turbine. I would agree with that assessment. A GT35 will have surge issues midrange at higher boost levels because the engine can't process the minimum flows required off the compressor wheel when using a .63 A/R. For a stock headed engine the GT30 is probably a better choice. Just for comparison, our Bonneville Development Engine is over 700HP, and for the altitude we likely will be running a GT37 or maybe a GT42 IF we can get a hotside A/R in the 0.82 range. And I'm laying money our RPM and Power levels are a tad more stringent that what you are considering! Right now we're between a GT35 which runs out of air (we're stonewalling the compressor), and a GT37 which handles the flow, but won't at 4200 feet of Bonneville's Track. Quote Link to comment Share on other sites More sharing options...
S130Z Posted November 12, 2010 Share Posted November 12, 2010 The feeling that just came over me, when Tony D agreed with me, was an unrepeatable euphoria similar to that of only the most potent hallucinogens and opiats..... Anyways.... Are you sticking with the stock intake? I belive my GT30 is starting to surge above 20psi. Give us a little more info on what your setup is man. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 12, 2010 Share Posted November 12, 2010 it's not your intake causing the surge, the above HP number was achieved with the stock intake... Quote Link to comment Share on other sites More sharing options...
bthomp Posted November 12, 2010 Author Share Posted November 12, 2010 im using the engine from a 78 280z, but going to use the 240sx tb, 280zx intake and exhaust mani's. but after looking at the pic, what you all said, and my goals for the momment, im going to go with a smaller t3/t4 turbo. Elevation ranges from 780-2,450ft. how much will that affect the turbo choice? Quote Link to comment Share on other sites More sharing options...
S130Z Posted November 13, 2010 Share Posted November 13, 2010 it's not your intake causing the surge, the above HP number was achieved with the stock intake... Stock intake as in......not ported? How about the cylinder head, is that ported? Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 13, 2010 Share Posted November 13, 2010 A 'ported' or even 'extrude honed' intake will cut about 30cfm off a properly ported cylinder head. It will be a restriction, but it won't stop the car from making more than 700HP and pulling hard to over 7500rpms... Quote Link to comment Share on other sites More sharing options...
SATAN Posted November 14, 2010 Share Posted November 14, 2010 (edited) here's a picture showing a GT45 turbo on a RB engine. Too big ... you decide! http://www.gtr.co.uk/forum/107028-r-i-p-s-rb30-gt45-street-engine-ready-testing.html The GT45 the OP is talking about is not a real GT45 as the one in the link you posted. The inducer on the OP's turbo is only 68.7mm where as a real GT45 is MUCH larger than that. To the OP, Since you never actually mentioned your goals for the vehicle (that I noticed), not one person here can tell you if this turbo is too big or not, despite what people have already posted in this thread. However, I will go off of a hunch that they are all right and the turbo will most likely be too big for the goals that you did not mention. Also, with the max elevation you will see being 2,450ft, you aren't going to have to worry about one turbo to the next in that aspect, as 2,500 feet is not that bad. I race at an elevation of 6,800ft. At that point, you DO have to take elevation into consideration when selecting a turbo. Edited November 14, 2010 by SATAN Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 14, 2010 Share Posted November 14, 2010 'not one person here can tell you if this turbo is too big or not, ' L28? too big. I'll lay money on it. The manner of the posting tells loads about his intended usage, if you've been around the site any at all you could see this. If a GT45 is too big for ME making 700+, chances are it's a 'compensation and intimidation show car piece' for anybody else with an L28... Quote Link to comment Share on other sites More sharing options...
bthomp Posted November 14, 2010 Author Share Posted November 14, 2010 so if its not a GT45, then what is it judging by the specs? I went to http://www.turbobygarrett.com/turbobygarrett/ and couldnt find which turbo it really is, looks like somewhere between GT40 & 42. My goal is just around 250whp, closer to 300 though, at least till i move out of the area i live in now and get closer any machine shops and what not. But that wont be for a few at least another 2 or 3 years from now... Im working on coverting the L28e from a 78 280z to a turbo. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 15, 2010 Share Posted November 15, 2010 My goal is just around 250whp, closer to 300 though, at least till i move out of the area i live in now and get closer any machine shops and what not. But that wont be for a few at least another 2 or 3 years from now... Im working on coverting the L28e from a 78 280z to a turbo. That 250 is possible with the STOCK turbo! The Eurospec Turbos were 200bhp and had no Catalyst, EGR, Pneumatic Conventional Distributor, and a 0.82 A/R Hot Side. That was at the stock 5psi boost. So 250 is child's play. 300? Stock internals, maybe a hybrid for efficencies sake, an intercooler and standalone like Megasquirt for proper fuel control. If you're not looking for 400+ right now, you need look no further than the GT30...if that as it likely will flow more than your engine can at some places in the RPM range. DEFINATELY not any 40-series GT! Absolutely, positively TOO BIG, period! No need for ANYTHING near that big. No way, no how. Quote Link to comment Share on other sites More sharing options...
TimZ Posted November 15, 2010 Share Posted November 15, 2010 so if its not a GT45, then what is it judging by the specs? I went to http://www.turbobygarrett.com/turbobygarrett/ and couldnt find which turbo it really is, looks like somewhere between GT40 & 42. My goal is just around 250whp, closer to 300 though, at least till i move out of the area i live in now and get closer any machine shops and what not. But that wont be for a few at least another 2 or 3 years from now... Im working on coverting the L28e from a 78 280z to a turbo. If it's really a Garrett GT-series then it would be the next size larger than the GT42, which is really huge - the GT42 can be good for over 1000hp in some applications. If this is the case, then Tony is right - not only would that turbo be too big, it would work really poorly at flow levels that low. You'd almost certainly make more usable power with the stock turbo. If it's some other turbo masquerading as a GT-series, I think I'd avoid it on principle alone. If they'll deliberately misrepresent themselves that way, what else are they not telling you? Here's what a GT42 looks like on an L-series... Quote Link to comment Share on other sites More sharing options...
BluDestiny Posted November 15, 2010 Share Posted November 15, 2010 not to get off topic, but TimZ what machine work do you have done to your engine? Quote Link to comment Share on other sites More sharing options...
bthomp Posted November 15, 2010 Author Share Posted November 15, 2010 (edited) well hell. it sounds like im going to go over my goal then with the build im trying for. guess I kind of underestimated how much I really am going to get out of this and should look back over my plans again, or just spend the money for it, But it also sounds like whatever the turbo really is, its still too big for what im doing for a while Edited November 15, 2010 by bthomp Quote Link to comment Share on other sites More sharing options...
SATAN Posted November 16, 2010 Share Posted November 16, 2010 'not one person here can tell you if this turbo is too big or not, ' L28? too big. I'll lay money on it. The manner of the posting tells loads about his intended usage, if you've been around the site any at all you could see this. If a GT45 is too big for ME making 700+, chances are it's a 'compensation and intimidation show car piece' for anybody else with an L28... I would lay money on it with you however, to answer a turbo is too big before knowing what the goal is, is impossible for anyone UNLESS they were assuming. But yes, judging by the question, It was very easy to assume the turbo is too big, as to anyone needing a turbo that size would most likely know why they are getting it. I was just trying to make a point. I guess it was a bad point to try and make in this thread though. Oops,LOL. Quote Link to comment Share on other sites More sharing options...
Tony D Posted November 17, 2010 Share Posted November 17, 2010 (edited) Satan, I think you got my point exactly! TimZ: That Exhaust Manifold....that....Exhaust....Manifold... AAAAAAAAAAAAAAAAUUUUUUUUUUUUUUUUGGGGGGGGGGGGGGHHHHHHHHHH! Edited November 17, 2010 by Tony D Quote Link to comment Share on other sites More sharing options...
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