frank280zx Posted November 8, 2004 Share Posted November 8, 2004 Intrestingly smaller Exhaust housing AR 48 Turbine Housing AR 60! 360 degree thrust bearing internal huge ( about 35 mm!!) waste gate that will be used as an Pop off valve by using a big head ex World rally Ford accumulator ( used in the same fashoin) or i will use it as waste gate, and leave the extarnal one to be, however the guy who built it said the use of an external one is 'nicer'and could reduce turbo lag between shifts slightly. me happy pics will follow !!! a small step for mankind, but a big one for this men The smaller AR on the exhaust side will give quick spool up and less lag, also the porche race cars went down on AR size when the got good IC's what i have, and lots of us use ( big NPR's etc).. just because the quicker spool, and suposivly cooler exhaust temp . The guy who built my turbo is working on his twin turbo L28 stroker (with forged s2000 pistons), and is very respected in World rally cross and F1( back in the 80's) turbo guy, He set up a respectable known company and worked closely with BEA and rayjay, so he knows his stuff.. Ill let you know what the findings are, is this a revolution smaller ar's on t3/t4's or would it be better suited for drivabillity and high speeds, and not as good for qauter miles? This set up is ensured to be at full boost at 2500 rpm and will maintian this easely upto 5500 the stock engine is not set up for much more evectivly anyway. however quick spool up was key ... Since Porche race cars and street cars, all went down on there AR's when the got to install the beter IC seemingly the exhaust temp drops Xander and i cant really make anything of that theory but note the turbine wheel is not stock either it has double scoops, and more than most wheels i have seen (not that i have seen that much but still what you see on ebay and here). I called the guy who made it last night, however he wasnt in, to try and get the specs, it is one that they used for f1 turbos, all very Funky. a smaller ar would make it to spool faster when i go for plain logic, but... Im very eager to find out if it indeed will work better, he advized this, and het knows turbos and the l28 so im not going agianst this yet, as he is the pro Ill keep you updated this might be a revolution. what ya think? Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted November 8, 2004 Share Posted November 8, 2004 To be honest a .48 a/r isn't a great idea on our engines. It's going to cause a LOT of exhaust back pressure in the manifold. maybe 2.5 times the pressure you're making on the compressor side! It also will die out in the upper RPMs, I'm not sure what you're going to use this car for, but it probably wont be a great drag turbo. For something like auto-x, that doens't need a lot of boost or high RPM this would be fine. I'm not sure how it would do on a road course. Just my take on the small exhaust housing. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted November 8, 2004 Author Share Posted November 8, 2004 That is what i would think aswel, however im not building a drag car but a road/circuit high speed car. Or as afriend tells me, 'a circuit car that happens to be road legal ' I am planning to run at 15 to 17 psi and set the overboost on my Greddy profec a to 20 psi (give or take a psi or two), also we will be making exhaust mainifolds, that will help getting the backpressure down by improving the flow over the stock unit. The exhaust house has a 3"outlet and aside from the compression side its size it seems much better desinged for flow than the stock nissan unit. I will also be fabricating a 3"dp and not with the factory 90+ degree corner. I have to agree i have more or less the same worries, however agian these are my psi goals for now Also this guy pointed out series of cars that dropped their AR sides due to larger intercoolers, so he could back up his statement And since im not adressing the cam there is no need to rev past 6000 rpms, due to teh fact the car really doesnt do much after that ( or even 500 rpm before) sure this has some cause in the stock fuel managament, but largly due to the engines lay out. well we will see ... curious did anyone do this in the past? however a great trade to a bare l28 block and a p90a head with some misc parts ! note it is brand new ! Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted November 8, 2004 Share Posted November 8, 2004 I have no doubt you've done your homework. I'm just expressing my concerns. Our engines are large and flow a lot of exhaust by nature. I see no relavence between large intercoolers, and small turbo exhaust housings. The .48 a/r is simply a 4 cyl exhaust housing. Anyway, definatly let us know how it works out. Im sure many have been wanting to try this out, but in fear of the reprecussions. I myself did a bastard of a turbo this weekend, straight, stock t3, with a t4 54 trim wheel inside (machined to fit). Quote Link to comment Share on other sites More sharing options...
frank280zx Posted November 8, 2004 Author Share Posted November 8, 2004 I was planning on using a normal t3 (stock exhaust housing), so Im sceptical to a certain extend aswel. Though this guy who knows his stuff told me to go this way and convinced me. so basicly i did my homework, but according to this guy, for european road conditions (sprinting in diffrent rpm bands) and drivability this would be the way to go. also note that the turbine wheel is a 'hybrid' so it will flow more air (more air more gains!) well it is a nice test, im very eager though i need to finish my car so this wont be before next spring. so do you know anybody that did this? and the drivabillity factor does play a role here. I agree on with you however it is an experiment that given this guys rep and experiance with the L series and turbos im willing to try and believe. even when it goes agianst my homework, wich is based on american forums under american conditions, and mainly qauter racers.. i think this guy might have a point. However the large IC smal AR housing is weird concept to me too, I talked it over with Xander last night and we both where more or less lost on this info. But agian this guy builds turbos for world rally cars, so he might know his stuff. Im building a stable drivable fast car that can mantian high speeds for durable times, not a just a sprinter so note this does put a differnt strain and therfor approach to it ( and boost behavior) driving at 220KMH for sustaind time will put me up for diffrent cahllanges... well im your test platform if it does not work i just have to take my stock t3 AR for now i think this will widen my powerband, and make it more drivable anybody? Quote Link to comment Share on other sites More sharing options...
frank280zx Posted November 8, 2004 Author Share Posted November 8, 2004 Dont know if it works for anybody but the exhaust housing says M4 and DH1 and DHSG N! maybe somebody knows what these number mean but else has thoughst on smaller ar housings? this could be intreting because it would theoretically be a postive thing for powerband and drivabillity from the information i got to a certain extend, however did anybody here do it Quote Link to comment Share on other sites More sharing options...
Guest Cronic Posted November 8, 2004 Share Posted November 8, 2004 It would be great for a daily driver, or even auto-x because of the short spool time. It just would cause massive manifold pressure under higher boost, and high rpms. Quote Link to comment Share on other sites More sharing options...
Clifton Posted November 9, 2004 Share Posted November 9, 2004 .48 OMG Is it a L28D? Why do you want so much spool at revs that the car will rarely be in? Have you driven the car with the .63? Porsche may have went down on there a/r's, I don't know, but there is no way they were even as low as a .63 to begin with. I did run a .48 on a 2.4l 4x4 Nissan hardbody and ended up swapping to a .63. You will have alot more back pressure at cruise and under boost, lowering your overall power. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted November 9, 2004 Author Share Posted November 9, 2004 again this is my concern aswell, but we will see, since this guy seemed not to talk BS so lets asume he is right i do have a 60AR T4 exhaust house, however it would spool up really quick right? and at max 20 to 22 PSI for overboost ( on my controller) But what did you make the change to a bigger AR? and what where the futher specs to your turbo ? you said it spooled up fairly quick right ? anyhow i want somewhere between 300 and 350 RWHP and a broad powerband, Im not getting any or much use out of a big spool up time, so broad power band! this is what i told the guy, and he came up with this, shall i tell him to change it, and ifso for what ? Anybody have any figures on this set up ? I'm even more curious now, i mean i tend to lean towards this board but this guy knows his stuff, are we all wrong, or would this be better for drivabillity ??? upto know i only drove the car at 10psi with the stock turbo, im just really curious to test both AR's ( stock and this one) So what would my power potential be at say 15 And 20 PSI could i not reach the 300 mark? Quote Link to comment Share on other sites More sharing options...
Clifton Posted November 9, 2004 Share Posted November 9, 2004 The specs on the turbo I ran on the 2.4l were T3 60 trim compressor(stock 280ZX). and had a chrysler .48 turbine housing. It spooled more than fast enough. Knowing the a smaller a/r chokes and hinders top end I swapped the .63 housing on. It slowed it a little but not much. This guy may know his stuff with trims and maps but I would question his matching on this application. If you are looking 20-22 psi you are looking to make a bit of power, easily 350-400 depending on turbo. With something small you may struggle to reach 300 whp and probably not on pump gas. I don't know what you mean by 60 a/r T4 exhaust house. Are you refering to the compressor housing? Do you know what wheel he was going to use on the compressro? I am biased to larger, a little laggier turbos for max power. Zcarsmakesmyheadhurt on this board does alot of turbos. He has a shop. He might have some first hand experience with different set ups and could give a little more help. Quote Link to comment Share on other sites More sharing options...
frank280zx Posted November 9, 2004 Author Share Posted November 9, 2004 well after talking to they guy i decided to test this set up, it does make a whole lot of sense, even big track cars are using a similar set up. In theory this will give a very flat power curve that will give me more 'averange' power on tap than a peak power. So i might have lower peak power but more in the power band... By 60 AR i mean the compressor. and i will be building an exhaust manifold with bigger smoother runners hopefully before running it (i will use an extarnal waste gate either way). Im very eager to find out, since it might be much more drivable, and on street or track even faster , theoretical that is. there has to be somebody who did this right !! btw pump gas here is 98 and we have VMAX at 100 or even 105 at the border and in germany Quote Link to comment Share on other sites More sharing options...
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