AshBhp Posted October 23, 2006 Share Posted October 23, 2006 TLicence has a Blitz twin set up. http://www.mkivsupra.net/vbb/showthread.php?t=70974 Quote Link to comment Share on other sites More sharing options...
tbourner Posted October 23, 2006 Share Posted October 23, 2006 That's not a sequential system though is it? I thought loads of people had big twins but none I've heard of running in sequential mode. Quote Link to comment Share on other sites More sharing options...
Alex Posted October 23, 2006 Share Posted October 23, 2006 There arn't any big sequential twin "kits". Some people have fabricated a system usung larger turbos but then what are you gaining...as you start to use bigger and bigger turbo's you lose more and more down low...in which case you might as well have had a Single. A small single like a T61/GT35R will out drive stock twins from 3000 rpm fairly easily. But no there isn't any sudden rush of the second turbo, and thank god for that! It's so much more controllable, no sudden torque spike = more predictable = able to make better safer progress. Quote Link to comment Share on other sites More sharing options...
Kranz Posted October 23, 2006 Share Posted October 23, 2006 The most logical answer to sequential small twins Vs single woul surely be an ECU controlled large single VNT?? That way you could dial in the boost map you want at all rpms, and the VNT would close/open to achieve it using both closed & open loop control. So at any point between idle and max power you could get the boost you want. Now, which Garrett VNT to go for??? Quote Link to comment Share on other sites More sharing options...
Wez Posted October 23, 2006 Share Posted October 23, 2006 I think a well matched small/medium sized single can be better than a BPU right through the rev range, if setup correctly. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 23, 2006 Share Posted October 23, 2006 I think a well matched small/medium sized single can be better than a BPU right through the rev range, if setup correctly. The only medium sized single vs BPU graphs we've seen is Homer's vs Terry's. Terry gains huge top end, and a massive chunk of midrange, and below 3000rpm doesn't appear to lose much to Homer either (shame the runs didn't start from 900rpm instead of 2400rpm for Homer & 2000rpm for Terry), but look how much money, time and thought went into Terry's car vs Homer's- I'd like to see a BPU car with atleast an Emanage overlaid with Terry's car, or a basic single vs Homer's. (disclaimer- turbo sizes are an absolute mystery to me) Regarding sequential upgrades- wouldn't a GT25(DBB?) in a sequence outspool a single T60? Sure it'd be laggier than the stock first turbine, but by how much? Also, wasn't the original system a load based system? Would the switch over on the orginal manifold with a pair of GT25's still happen at 3500-4000rpm, as that is when the valves of the manifold switch over? If so would the second turbine stall because it would need more airflow than the CT12 when it was supposed to be online? (if that makes sense?) Quote Link to comment Share on other sites More sharing options...
Wez Posted October 23, 2006 Share Posted October 23, 2006 I am happy for someone to overlay my dyno on a BPU car. As for the stock system, with an AEM installed the VSVs are controlled at RPM points not load. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 23, 2006 Share Posted October 23, 2006 I am happy for someone to overlay my dyno on a BPU car. As for the stock system, with an AEM installed the VSVs are controlled at RPM points not load. Hmmm, that'd sure make life easier trying to dictate the switchover from one to both. I think lol! Quote Link to comment Share on other sites More sharing options...
Wez Posted October 23, 2006 Share Posted October 23, 2006 I ran the AEM on my stock tubbies for a long time before going single and I found the control to be much more reliable and smoother. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 23, 2006 Share Posted October 23, 2006 I ran the AEM on my stock tubbies for a long time before going single and I found the control to be much more reliable and smoother. Have you got before and after graphs with the AEM- BPU vs Single? Quote Link to comment Share on other sites More sharing options...
Homer Posted October 23, 2006 Share Posted October 23, 2006 Gaz, what you're saying is pretty much spot on, Terry's car has so much more torque through the mid range it's almost unbelievable, However after being out in Wez's car and seeing the dyno plot, it has even earlier spool (!!), though less top end. I'll sort an overlay graph shortly. I'd like to see a BPU car with atleast an Emanage overlaid with Terry's car, or a basic single vs Homer's. Give it a couple of weeks and my budget single should be on the road. Its a reasonably large turbo being a T67, but should come in at less than £2k all in (plus diy 'driveway' install). It'll be off to SRR for a dyno run as soon as its mapped so will get them to plot against previous stages of modification (Charlie has all the history saved in their computer). Quote Link to comment Share on other sites More sharing options...
Wez Posted October 23, 2006 Share Posted October 23, 2006 Have you got before and after graphs with the AEM- BPU vs Single? Sadly I never dynoed the car until it was being mapped for the single, all the tunning on the stock tubbies was done on the road. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 23, 2006 Share Posted October 23, 2006 Give it a couple of weeks and my budget single should be on the road. Its a reasonably large turbo being a T67, but should come in at less than £2k all in (plus diy 'driveway' install). It'll be off to SRR for a dyno run as soon as its mapped so will get them to plot against previous stages of modification (Charlie has all the history saved in their computer). That should make very, very interesting viewing, as I assume all that's changing is the method of asperation? Quote Link to comment Share on other sites More sharing options...
Homer Posted October 23, 2006 Share Posted October 23, 2006 For those that were interested here's BPU vs Wez's PHR stage 1 vs Terry's T61 dbb: PHR stage 1 = dark blue T61 dbb = light blue Jspec BPU = Red and green Its by no means a scientific test but gives a rough idea of the difference between small/mid single and BPU. Quote Link to comment Share on other sites More sharing options...
Homer Posted October 23, 2006 Share Posted October 23, 2006 That should make very, very interesting viewing, as I assume all that's changing is the method of asperation? Only the turbo (entire exhuast side stuff) and the injectors are being changed, plus the ECU. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 23, 2006 Share Posted October 23, 2006 Only the turbo (entire exhuast side stuff) and the injectors are being changed, plus the ECU. That's a damn shame for comparison purposes. Wez's car looks fantastic! It's odd that your first turbine appears to be doing the square root of fuck all according to the graphs- I wonder why that appears to be the case, and would this hold true if both you and Wez did a side by side test from 30-40-50 (as low as possible) in 6th if you'll remain side by side as the graph dictates until Wez leaves you for dead at 3000rpm? Hypothetically speaking. Quote Link to comment Share on other sites More sharing options...
Homer Posted October 23, 2006 Share Posted October 23, 2006 Not sure what you mean Gaz, you can't go single without an ECU change. It'd be a worthless comparison between BPU and single anyway since a single must have a full remap for it even to start up/idle, let alone run on boost. Edited to add: what I mean is a BPU car has a stock ECU, a single must have an aftermarket ECU (whether standalone or piggyback is irrelevant). Its impossible to compare BPU and single using the same ECU as it'd have to have a complete remap/upgrade to work. The conversion I'm doing is the most basic you can get so it's a fair comparison between good BPU and base spec single. Quote Link to comment Share on other sites More sharing options...
Wez Posted October 23, 2006 Share Posted October 23, 2006 In my opinion the ECU and mapping is were most of the gains are made. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 23, 2006 Share Posted October 23, 2006 Does anyone know if such a setup exists yet? I want some and would even be willing to pay top dollar, as I think this setup would rock and be one of a first..... Could this be made up as a bespoke? Is there someone out there that could do it.......???? I dont want a single as I would miss the sequential setup too much and Hybrids are my last limit in that case...... http://mkiv.com/publications/other/street_power/spring_99/power03.jpg http://mkiv.com/publications/other/street_power/spring_99/power04.jpg I assume that prototype kit was going to cost about $10,000. From what I can glean this included: 2x HKS GT2530 DBB turbochargers 2x 25mm steel turbo to manfold adaptor plates HKS Dual Dragger exhaust (cat-back only) HKS cone air filter and intake pipe. Front mounted intercooler HKS Electronic Valve Controller (EVC iv boost controller) HKS Vein Pressure Converter (fuel controller) HKS Turbo Timer HKS boost guage http://mkiv.com/publications/road&track/8_98/rt898_07.jpg Now, they say 380wrhp, or 420bhp at the fly, at 17psi. But that's the yanks for you, torque is very dissapointing at 358lbsft (my car does that with just a decat). Emissions data: http://mkiv.com/publications/road&track/8_98/rt898_14.jpg Makes you wonder what it'd do with decats and if you upped the boost & used an Emanage... Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 23, 2006 Share Posted October 23, 2006 Not sure what you mean Gaz, you can't go single without an ECU change. It'd be a worthless comparison between BPU and single anyway since a single must have a full remap for it even to start up/idle, let alone run on boost. Edited to add: what I mean is a BPU car has a stock ECU, a single must have an aftermarket ECU (whether standalone or piggyback is irrelevant). Its impossible to compare BPU and single using the same ECU as it'd have to have a complete remap/upgrade to work. The conversion I'm doing is the most basic you can get so it's a fair comparison between good BPU and base spec single. YHPM Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 24, 2006 Share Posted October 24, 2006 How do these compare to the CT12's? GT2530: COMPRESSOR: -Wheel- 63 Trim - 47.7 Inducer / 60.1 Major -Housing- 60 Inlet / 50 Outlet - 0.60 A/R TURBINE: -Wheel- 76 Trim - 53.8 Major / 47.0 Exducer -Housing- GT25/T3 inlets / Internal GT25/Skyline Type oulets - 0.64 A/R Ah, think I've found something: CT12B: 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 Still means nothing to a dullard like me Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 24, 2006 Share Posted October 24, 2006 See I can keep finding this stuff but I don't know what to do with it lol. http://turbobricks.com/resources.php?content=turbodata Quote Link to comment Share on other sites More sharing options...
Alex Posted October 24, 2006 Share Posted October 24, 2006 Still think it's a total waste of effort...the gains are so minimal...and as I've pointed out once you start using bigger turbo's you lose the point of the sequential system, which is to have low down power. Quote Link to comment Share on other sites More sharing options...
Gazboy Posted October 24, 2006 Share Posted October 24, 2006 Still think it's a total waste of effort...the gains are so minimal...and as I've pointed out once you start using bigger turbo's you lose the point of the sequential system, which is to have low down power. In theory shouldn't a GT25DBB still spin up faster than a T61? Quote Link to comment Share on other sites More sharing options...
Alex Posted October 24, 2006 Share Posted October 24, 2006 In theory shouldn't a GT25DBB still spin up faster than a T61? Yes 1 will but then do you gain anything over the CT12b? Quote Link to comment Share on other sites More sharing options...
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