lovatt Posted July 27, 2004 Share Posted July 27, 2004 can the first turbo handle more boost like the second ? or is it weaker, only thinking this as people dont up the boost on the first turbo Link to comment Share on other sites More sharing options...
LeeT Posted July 27, 2004 Share Posted July 27, 2004 good question. i would like to know the answer too. i think there is a mod you can do to up the boost. Link to comment Share on other sites More sharing options...
LeeT Posted July 27, 2004 Share Posted July 27, 2004 just tried a quick search. try searching the words blue spaghetti Link to comment Share on other sites More sharing options...
lovatt Posted July 27, 2004 Author Share Posted July 27, 2004 thats what gave me the idea of putting a bleed valve on the first turbo ages ago, wouldnt put it to 1.2 bar as traction would be a problem but maybe just up it a bit (1 bar) for more umf off the line. people dont like bleed valves but i have had good results with mine as you can see from my sig Link to comment Share on other sites More sharing options...
Aerotop Dave Posted July 27, 2004 Share Posted July 27, 2004 Or could you make the second one come in with a real kick...? (because that's what I want!) Link to comment Share on other sites More sharing options...
lovatt Posted July 27, 2004 Author Share Posted July 27, 2004 all you need to do that is up the boost on the second turbo, easy mod most people do mate Link to comment Share on other sites More sharing options...
Roy Posted July 28, 2004 Share Posted July 28, 2004 so this is a manual bleed valve for the 1st turbo only ? what if you already have an EBC ? would this still work ? can the same be done with the 2nd also with an EBC ? Link to comment Share on other sites More sharing options...
LeeT Posted July 28, 2004 Share Posted July 28, 2004 Originally posted by Roy so this is a manual bleed valve for the 1st turbo only ? what if you already have an EBC ? would this still work ? can the same be done with the 2nd also with an EBC ? the EBC is already controlling the 2nd turbo so no bleed valve required for that. i run an ebc also and am thinking of trying the mod on the 1st turbo Link to comment Share on other sites More sharing options...
Roy Posted July 28, 2004 Share Posted July 28, 2004 it'll be interesting to know what you find out ... Link to comment Share on other sites More sharing options...
Ian C Posted July 28, 2004 Share Posted July 28, 2004 That blue spaghetti was a work of art I'm telling ya. Right, let's clear up a few things here. When the second turbo comes online you have both turbos running at once. The wastegate controls the boost of both turbo's. Treat it as one bigger turbo that's already spun up. The EBC controls the boost in this case. Under 4krpm, only turbo one is online. This spins up fast because it's small and this behaviour is what makes the sequential system so great - big turbo power, small turbo lag. The exhaust gas bypass valve on the first turbo serves two functions - one, it bleeds exhaust gas off to spool up the second turbo, and two, it acts as a wastegate for the first turbo by bleeding off this exhaust gas. This bleeder valve mod ups the boost the first turbo reaches. Now, you can't run 1.2bar on the first turbo just because you can run 1.2bar on the second one because, as I said above, it's *both* turbos, not just the second one. Boost pressure is a function of airflow, and airflow is a function of rpm. The reason you have another turbo come online is that one of these little turbos on it's own runs out of puff above 4000rpm, it simply can't flow enough air to feed 50%+ more demand from the engine as the revs rise. When the second one comes online, the demand on turbo #1 halves, so it can supply enough air to redline because it's got a mate helping it out I shut that bleeder valve ages ago (in fact it's in a bag now if anyone wants to buy it ) because the power difference between 0.8bar and 0.9bar on turbo 1 wasn't noticeable, and 1.0bar power dropped off quite dramatically (probably due to ignition timing being retarded as the intake charge temps rocketed). Also the boost pressure varied massively depending on temperature and phases of the moon. Your experiences may differ. -Ian Link to comment Share on other sites More sharing options...
Aerotop Dave Posted July 28, 2004 Share Posted July 28, 2004 So, if I've understood correctly, that now means you don't have pre-boost spooling on 2nd turbo now...? Link to comment Share on other sites More sharing options...
tDR Posted July 29, 2004 Share Posted July 29, 2004 Originally posted by Aerotop Dave So, if I've understood correctly, that now means you don't have pre-boost spooling on 2nd turbo now...? He doesn't have a 2nd turbo now............ lol Good informative read Ian Link to comment Share on other sites More sharing options...
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