Gazboy Posted April 27, 2005 Share Posted April 27, 2005 I don't think this question has been asked before... What are the actual limitations of the sequential system and the turbo's when tuning? Link to comment Share on other sites More sharing options...
Gazboy Posted April 28, 2005 Author Share Posted April 28, 2005 Anyone? Link to comment Share on other sites More sharing options...
CJ Posted April 28, 2005 Share Posted April 28, 2005 I don't think this question has been asked before... What are the actual limitations of the sequential system and the turbo's when tuning? Do you mean what level of boost can they take? The general concensus of opinion is that J-spec turbos should not be run much higher than 1.2 bar. Link to comment Share on other sites More sharing options...
SimonB Posted April 28, 2005 Share Posted April 28, 2005 The 1.2BAR thing is more due to insufficient fueling than anything else though, since most people that up the boost don't have the uprated fuel pumps, pressure regulators and/or injectors and electronics. If you have a single you pretty much have to have these things. At 1.3 BAR say then the stock turbos are out of their efficiency range, but they will still produce more power than at 1.2BAR provided your fueling, intercooling etc are up to it. Wouldn't want to push it much further than that myself. I run mine now at 1.3BAR, with increased fuel pressure, uprated fuel pump and an Emanage to control the fueling. Oh, and a FMIC. Last year before it was mapped properly it made 430bhp at the hubs on Thors (generally regarded as quite optimistic) dyno. I've improved a number of things since then, I expect it to be around the same reliably now. That's with standard Jspec turbos btw. Link to comment Share on other sites More sharing options...
Gazboy Posted April 28, 2005 Author Share Posted April 28, 2005 Why is the sequential system usually junked then, in favour of a big single or HKS twins? Why can't you stick larger than stock turbos on to run on the sequential set-up? Seems a shame to waste the low down grunt that the stock system provides??? Link to comment Share on other sites More sharing options...
Ian C Posted April 28, 2005 Share Posted April 28, 2005 One look at the sequential system will answer that question You try fitting in something bigger! -Ian Link to comment Share on other sites More sharing options...
eyefi Posted April 28, 2005 Share Posted April 28, 2005 because no alternative AR ratio is available for the turbines, if it was it would probably mean a custom manifold, custom exhaust dumps from the turbines and alot of custom valving for these pipes. tricky and expensive. the singles are a lot simpler and some perform nearly like the seqential system at low revs, but without the awkward transitions. it's a major headache for not much gain. don't forget as soon as you put on the larger steel turbos you loose a lot of that response you feel now with the tight AR ceramics. Link to comment Share on other sites More sharing options...
Gazboy Posted April 28, 2005 Author Share Posted April 28, 2005 So it's a lack of physical space that limits the sequential system? Am I right in thinking a JDM has CT12 turbo's, and that a rev3 MR2 CT20 turbo is a bigger turbo? (I just wondered if the numbers stood for something or it was an ID) Link to comment Share on other sites More sharing options...
SimonB Posted April 28, 2005 Share Posted April 28, 2005 That plus it would be a very specialised product to work with the sequential system. The single turbo kits are based on generic turbos that can be used for loads of applications otherwise they would cost a fortune. Link to comment Share on other sites More sharing options...
Jake Posted April 28, 2005 Share Posted April 28, 2005 Am I right in thinking a JDM has CT12 turbo's Yes, so do the UK Spec Supras (and US/Euro spec, all MKIV TTs have CT12B turbos) Link to comment Share on other sites More sharing options...
Gazboy Posted April 28, 2005 Author Share Posted April 28, 2005 Ah! Just found this: Sequential Turbo's CT12B(Japanese) Turbine Size 60mm/48mm (big/small end of same blade) Compressor Size 62mm/39mm (big/small end of same blade) Turbine material Ceramic Scroll area (mm^2) 600 A/R ratio 0.42 CT12B(export) Turbine Size 52mm/44mm (big/small end of same blade) Compressor Size 58mm/39mm (big/small end of same blade) Turbine material Steel Scroll area (mm^2) 740 A/R ratio 0.53 Posted on here about three years ago. Link to comment Share on other sites More sharing options...
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