JamieP Posted April 24, 2007 Share Posted April 24, 2007 Ive heard tallk of bigger IC's making a difference to spool time? true? Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted April 24, 2007 Share Posted April 24, 2007 yes Quote Link to comment Share on other sites More sharing options...
Lucifer Posted April 24, 2007 Share Posted April 24, 2007 Basic physics. Larger area to pressurise - longer it will take. Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted April 24, 2007 Share Posted April 24, 2007 quick search found this but i get feeling there are better threads about. http://www.mkivsupra.net/vbb/showthread.php?t=91962 Quote Link to comment Share on other sites More sharing options...
SimonB Posted April 24, 2007 Share Posted April 24, 2007 At the flow rates of air you get it's not going to make any practical difference. The increase in volume is tiny compared to the volume of air flowing through every second. Quote Link to comment Share on other sites More sharing options...
Lucifer Posted April 24, 2007 Share Posted April 24, 2007 At the flow rates of air you get it's not going to make any practical difference. The increase in volume is tiny compared to the volume of air flowing through every second. Agreed but that depends on teh response of the turbo - I think is the question he is asking. HOwever - you shoudl have a good quality intercooler properly ducted then you dont need to go over kill. Quote Link to comment Share on other sites More sharing options...
JamieP Posted April 24, 2007 Author Share Posted April 24, 2007 Im going from a 2 row to a 102mm blitz lm 3 row, just wondered if i will notice any difference in spool time:) Quote Link to comment Share on other sites More sharing options...
SimonB Posted April 24, 2007 Share Posted April 24, 2007 Im going from a 2 row to a 102mm blitz lm 3 row, just wondered if i will notice any difference in spool time:) I very much doubt it mate. I didn't notice any difference between a stock sidemount and my Blitz LM when I fitted it - that was on stock turbos at the time mind. Quote Link to comment Share on other sites More sharing options...
JamieP Posted April 24, 2007 Author Share Posted April 24, 2007 I very much doubt it mate. I didn't notice any difference between a stock sidemount and my Blitz LM when I fitted it - that was on stock turbos at the time mind. Thats what i wanted to hear, thanks:) Quote Link to comment Share on other sites More sharing options...
jagman Posted April 24, 2007 Share Posted April 24, 2007 I think some perspective is required,if the engine is using around 8 cubic feet of air /second (stock engine) provided by the turbos,what would be the extra volume of a large i/c verses a smaller one ? mathmatician reqd:) if as a guess its .8 cubic foot then 1/10th of a sec to fill ,all ball park numbers but I dont think it would be far off .8 of a cubif foot would be about the size of a portable tv ,but the internal volume of an intercooler with cooling fins and tubes probably lots less Quote Link to comment Share on other sites More sharing options...
ajazyasin Posted April 24, 2007 Share Posted April 24, 2007 Glad to hear all this. I was really worried that between a large FMIC and enlarged plenum&TB it would cause response issues. Quote Link to comment Share on other sites More sharing options...
Jake Posted April 24, 2007 Share Posted April 24, 2007 Look at it this way, how many litres of air is the engine ingesting at say 3000rpm? Even at atmospheric pressure it would be 3000cc x 1500rpm which is 4,500 litres per min. (if I've done that right) I can't see a couple of extra litres of intercooler volume making sod all difference really. Quote Link to comment Share on other sites More sharing options...
jagman Posted April 24, 2007 Share Posted April 24, 2007 it would if it was 8 cubic feet big !! Quote Link to comment Share on other sites More sharing options...
Kranz Posted April 24, 2007 Share Posted April 24, 2007 A large volume of intercooler that is free flowing is much better than a small volume that is restrictive. The large volume one will be slower to build boost, but the mass flow will be higher (mass flow makes power, not just pressure). The small volume restrictive one will build up pressure but the restriction will reduce mass flow, hurting power. So volume = small increase in lag but more power. Quote Link to comment Share on other sites More sharing options...
Jake Posted April 24, 2007 Share Posted April 24, 2007 The large volume one will be slower to build boostHow much slower though? We're talking about milliseconds, aren't we? Also Jamie, on a related note, A DBB turbo would help because boost doesn't drop boost between gearchanges as much as with a journal bearing turbo. Quote Link to comment Share on other sites More sharing options...
Lucifer Posted April 24, 2007 Share Posted April 24, 2007 A DBB turbo would help because boost doesn't drop boost between gearchanges as much as with a journal bearing turbo. Where on earth did you dream that up? Why shoudl it not drop, there is no inertia spinning the hot side - no matter what bearign you have. Quote Link to comment Share on other sites More sharing options...
Jake Posted April 24, 2007 Share Posted April 24, 2007 Where on earth did you dream that up? Why shoudl it not drop, there is no inertia spinning the hot side - no matter what bearign you have.Oh so the turbo just stops spinning the moment you take your foot off the gas to change gear does it? Quote Link to comment Share on other sites More sharing options...
Lucifer Posted April 24, 2007 Share Posted April 24, 2007 Oh so the turbo just stops spinning the moment you take your foot off the gas to change gear does it? NO, but you have just proved my point, IN laymans terms it has 800RPM's of inertia spinning it. So bearings really dont make any noticable differnnce at all. HOwever it will get on boost again quicker, but as for dropping it - sorry no. Quote Link to comment Share on other sites More sharing options...
Kranz Posted April 24, 2007 Share Posted April 24, 2007 How much slower though? We're talking about milliseconds, aren't we? Probably something like that, in any case I think not noticeable by your average Supra driver And losing boost between gear changes??? A DBB turbo has lower friction and a similar inertia as a hydrodynamic journal bearing turbo. So on a gear change the turbo will spin down slightly slower than a journal bearing turbo... in much the same way that it will spool up faster when under load. Or have I got something fundamentally wrong? Quote Link to comment Share on other sites More sharing options...
Lucifer Posted April 24, 2007 Share Posted April 24, 2007 Probably something like that, in any case I think not noticeable by your average Supra driver And losing boost between gear changes??? A DBB turbo has lower friction and a similar inertia as a hydrodynamic journal bearing turbo. So on a gear change the turbo will spin down slightly slower than a journal bearing turbo... in much the same way that it will spool up faster when under load. Or have I got soemnthing fundamentally wrong? Thats correct, but virtually not noticable in ani case. Quote Link to comment Share on other sites More sharing options...
Jake Posted April 24, 2007 Share Posted April 24, 2007 NO, but you have just proved my point What was the point you were trying to make? It was that a spinning turbine wheel has 'no inertia', wasn't it? IN laymans terms it has 800RPM's of inertia spinning it. Where did this figure of 800rpm come from? So bearings really dont make any noticable differnnce at all. HOwever it will get on boost again quicker, but as for dropping it - sorry no. So you're saying DBB turbos don't spin for longer than journal bearing ones once the flow of gas through the turbine has stopped? Quote Link to comment Share on other sites More sharing options...
Lucifer Posted April 24, 2007 Share Posted April 24, 2007 What was the point you were trying to make? It was that a spinning turbine wheel has no inertia, wasn't it? Where did this figure of 800rpm come from? So you're saying DBB turbos don't spin for longer than journal bearing ones once the flow of gas through the turbine has stopped? LOL Night Jake. Quote Link to comment Share on other sites More sharing options...
Whitesupraboy2 Posted April 24, 2007 Share Posted April 24, 2007 Thats correct, but virtually not noticable in ani case. but having said that all these slights Bigger intercooler = slower spool DBB = less drop in turbo spinning during gear change All help to even out changes and get that bit more. I think Jamie has got to the stage where he's looking for that bit more Quote Link to comment Share on other sites More sharing options...
Kranz Posted April 24, 2007 Share Posted April 24, 2007 Thats correct, but virtually not noticable in ani case. Much like a slightly bigger volume wouldn't be that noticeable Its sort of like comparing limit components. By that I mean if you have the fastest spooling DBB turbo of a type and also have the best flowing intercooler of a certain size, then sawp them for the slowest spooling DBB turbo of the same type and the worst flowing IC of that size..... would anyone be able to FEEL the difference??? Quote Link to comment Share on other sites More sharing options...
Kranz Posted April 24, 2007 Share Posted April 24, 2007 but having said that all these slights Bigger intercooler = slower spool DBB = less drop in turbo spinning during gear change All help to even out changes and get that bit more. I think Jamie has got to the stage where he's looking for that bit more That bit more = hugely more expensive as you really need to get serious fully instrumented engine dyno time to actually try out each combination of parts & settings. Otherwise its really just a best guess. TBH a little squirt of N2O would cure any small lag issues Quote Link to comment Share on other sites More sharing options...
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