INDYPWR Posted January 24, 2006 Share Posted January 24, 2006 anyone here converted their jspec twins to uk/us twins? if so, what is needed to complete the project? i heard that you will need the flwg parts below: -550cc injectors and resistor packs -us/uk twin and exhaust manifold -upgrade fuel pump anything else missing? thanks Link to comment Share on other sites More sharing options...
Nic Posted January 24, 2006 Share Posted January 24, 2006 why would you want to take that backward step? Link to comment Share on other sites More sharing options...
Robert Posted January 24, 2006 Share Posted January 24, 2006 might aswell go single Link to comment Share on other sites More sharing options...
steve single Posted January 24, 2006 Share Posted January 24, 2006 UK/US spec ecu. Link to comment Share on other sites More sharing options...
Homer Posted January 24, 2006 Share Posted January 24, 2006 might aswell go single I'm guessing the guy has a jspec and blown turbos, replacing them with jap model ones would be tricky in the US, there's not going to be many floating around. US Spec ones would be abundant so probably found some cheap ones for sale. In answer to the question you should not need the injectors, the jspec ones can handle 1.2bar (on jspec tubbies) and 400-450 flywheel horsepower. Provided you keep the boost a little lower (say 1 bar) you shouldn't get any detenation. You'll presumably still have the Jspec cams so they won't make the most of the top end power anyway. If you do go for these injectors you will also need to replace the ECU. The fuel pump should be replaced with a Walbro one anyway, especially if you're running more than stock boost. Other than that you need only the turbo and the manifold (inc the actuators). Link to comment Share on other sites More sharing options...
JohnA Posted January 24, 2006 Share Posted January 24, 2006 anyone here converted their jspec twins to uk/us twins? ah, but are you man enough? Got a G-suit? Seriously, as said the ECU will be different for sure (since it handles bigger injectors) The downpipe is also different, along with the inlet cam (if you want to be thorough) There could well be other bits that need changing, especially if it's an auto. Also remember that UK and US ECUs are not exactly the same, at least the ignition curves are different. There are more than one versions of the US ECU as well, the later ODBII being favoured. That's assuming that you haven't got a VVTi version, because then you're a bit stuck. As rallure said, you might as well go single... Link to comment Share on other sites More sharing options...
INDYPWR Posted January 24, 2006 Author Share Posted January 24, 2006 sorry to confuse everyone....as you can see, i am a newbie here... i am running the jspec twins right now and would like to upgrade to US TWINS. my installer used US WIRING HARNESS with jspec ecu as well. he did some modification on harness and it works perfectly fine. so, i am running the us spec harness. the jspec ones are not blown, but would like to get more hp since the us twins can handle more power. doesn't the jspec ECU handle the 550's? with the resistor packs? or i need to get US ECU? i do have walbro pump installed so that's ok. HOMER: so how do i achieve 400-450 flywheels hp with jspec twins? i am at bpu right now. Link to comment Share on other sites More sharing options...
GeordieSteve Posted January 24, 2006 Share Posted January 24, 2006 For the price and the problems it just really isn't worth it Link to comment Share on other sites More sharing options...
INDYPWR Posted January 24, 2006 Author Share Posted January 24, 2006 For the price and the problems it just really isn't worth it so, would you say to go 'single'? Link to comment Share on other sites More sharing options...
GeordieSteve Posted January 24, 2006 Share Posted January 24, 2006 For the money and the fact you want more power then yes, without a doubt Link to comment Share on other sites More sharing options...
CJ Posted January 24, 2006 Share Posted January 24, 2006 so, would you say to go 'single'? Yep - Given the choice of "upgrading" to the US/UK spec over the J-spec or going single then there is no choice. Link to comment Share on other sites More sharing options...
INDYPWR Posted January 24, 2006 Author Share Posted January 24, 2006 well, i dont really want to achieve BIG pwr gains... i just need a little bit more than what i have right now. any suggestions on how to get more power out of the jspec twins? how can someone achieve 400-450 wheel hp with the jspec? Link to comment Share on other sites More sharing options...
Homer Posted January 24, 2006 Share Posted January 24, 2006 Going to US turbo's will give a negligible power increase, if at all. Its just not worth it. Have a search for "BPU" on the forum here to see how to get the most out of the J-spec engines. Just a few simple mods (Decat & restrictor, FCD, spark plugs & fuel pump) should see you to 400bhp, a decent IC then maybe some cams should see 450. Some people claim to have more but that’s more likely down to dodgy dyno figures A decatted Jspec will also spool up noticeably quicker than the US spec equivalent. If you're after significant upgrades then single turbo is the route to go, even in the US it'll cost a few thousand. To do it properly in the UK typically costs £4k, a few thousand more if you go for a standalone ECU. Link to comment Share on other sites More sharing options...
Homer Posted January 24, 2006 Share Posted January 24, 2006 any suggestions on how to get more power out of the jspec twins?how can someone achieve 400-450 wheel hp with the jspec? You can't get that at the rear wheels, not on a Jspec or a US/UK spec supra with standard turbo's But we know well that US dyno's a little different to the rest of world... Link to comment Share on other sites More sharing options...
GeordieSteve Posted January 24, 2006 Share Posted January 24, 2006 Going to US turbo's won't give a negligible power increase, if at all. Its just not worth it. Just to save any confusion Link to comment Share on other sites More sharing options...
Robert Posted January 24, 2006 Share Posted January 24, 2006 so i was right then Link to comment Share on other sites More sharing options...
CJ Posted January 24, 2006 Share Posted January 24, 2006 well, i dont really want to achieve BIG pwr gains... i just need a little bit more than what i have right now. any suggestions on how to get more power out of the jspec twins? how can someone achieve 400-450 wheel hp with the jspec? IMHO, the only way you are going to see anything close to 450 BHP at the wheels is to get a single. There is no way that a BPU'd TT car will make that sort of power. Link to comment Share on other sites More sharing options...
Homer Posted January 24, 2006 Share Posted January 24, 2006 Just to save any confusion Surely it's "will give a negligible increase"? I.e. bugger all increase? English isn't my strong point Link to comment Share on other sites More sharing options...
GeordieSteve Posted January 24, 2006 Share Posted January 24, 2006 Sorry matie. Read it as "noticeable"... im off back to the thick corner Link to comment Share on other sites More sharing options...
INDYPWR Posted January 24, 2006 Author Share Posted January 24, 2006 well, i do have a decat but no restrictor. i also have fcd, colder plugs (nkg 6097's just installed), fmic, walbro pump, greddy profec b II (i hate this bc, very complicated to adjust), 3inch downpipe, and full exhaust. i have two decats but i truly believe, i need to gain more back pressure. i hate to deal with boost creep all the time and hitting fuel cut. i dont plan on changing the cams. damn, i already got the 550's and US TWINS with me....arrrhrhrhrhrhh Going to US turbo's will give a negligible power increase, if at all. Its just not worth it. Have a search for "BPU" on the forum here to see how to get the most out of the J-spec engines. Just a few simple mods (Decat & restrictor, FCD, spark plugs & fuel pump) should see you to 400bhp, a decent IC then maybe some cams should see 450. Some people claim to have more but that’s more likely down to dodgy dyno figures A decatted Jspec will also spool up noticeably quicker than the US spec equivalent. If you're after significant upgrades then single turbo is the route to go, even in the US it'll cost a few thousand. To do it properly in the UK typically costs £4k, a few thousand more if you go for a standalone ECU. Link to comment Share on other sites More sharing options...
SimonB Posted January 24, 2006 Share Posted January 24, 2006 IMHO, the only way you are going to see anything close to 450 BHP at the wheels is to get a single. There is no way that a BPU'd TT car will make that sort of power. Youcan get close, but not quite there. Mine clocked 430 at the hubs on Thors dyno at 1.3bar with uprated fueling etc. That's pretty much the limit. Link to comment Share on other sites More sharing options...
CJ Posted January 24, 2006 Share Posted January 24, 2006 Youcan get close, but not quite there. Mine clocked 430 at the hubs on Thors dyno at 1.3bar with uprated fueling etc. That's pretty much the limit. Ah, but that is hubs and not wheels. We all know that there is a vast difference between the two. Link to comment Share on other sites More sharing options...
INDYPWR Posted January 24, 2006 Author Share Posted January 24, 2006 Youcan get close, but not quite there. Mine clocked 430 at the hubs on Thors dyno at 1.3bar with uprated fueling etc. That's pretty much the limit. i once hit 1.2 bar, if i can remember, when the tt project was done on my soarer. i test drove it the first time and i hit 1.2bar. i got scared for a moment.....hehe Link to comment Share on other sites More sharing options...
Homer Posted January 24, 2006 Share Posted January 24, 2006 well, i do have a decat but no restrictor. i also have fcd, colder plugs (nkg 6097's just installed), fmic, walbro pump, greddy profec b II (i hate this bc, very complicated to adjust), 3inch downpipe, and full exhaust. i have two decats but i truly believe, i need to gain more back pressure. i hate to deal with boost creep all the time and hitting fuel cut. i dont plan on changing the cams. damn, i already got the 550's and US TWINS with me....arrrhrhrhrhrhh Well, I'd say you're likely to be at the limit of the jspec turbo's, what boost are you running at? 1.2bar is the 'safeish' limit for jspecs (That's around 18psi - can't remember what measurement is used over there!). You'll get a little more top end with the cams, but will need to reconsider your options if you want more power. You can't go straight to a small single on a jspec (even at low boost) as you'll need bigger injectors and a new ECU with custom Map. The injectors you have bought already will go some way to a small single setup, but to run higher boost you'll need 650's, plus you'll still need a new ECU. As stated already, US spec turbos will make virtually no difference to your current setup. More lag for sure, but with the combination of cams maybe a little more top end should be possible. Just not worth it really... Link to comment Share on other sites More sharing options...
INDYPWR Posted January 24, 2006 Author Share Posted January 24, 2006 tks homer.......and rest of the guys who chimmed in !! great thread !! homer, yeah i think 1.2 bar equals to 18psi. i only ran it once at 1.2 but didnt do it again. i would like to put the first catty to get more back pressure since i am just running w/o any cats at all ! maybe that will help me control the boost better with the greddy profec. tks again !!! Well, I'd say you're likely to be at the limit of the jspec turbo's, what boost are you running at? 1.2bar is the 'safeish' limit for jspecs (That's around 18psi - can't remember what measurement is used over there!). You'll get a little more top end with the cams, but will need to reconsider your options if you want more power. You can't go straight to a small single on a jspec (even at low boost) as you'll need bigger injectors and a new ECU with custom Map. The injectors you have bought already will go some way to a small single setup, but to run higher boost you'll need 650's, plus you'll still need a new ECU. As stated already, US spec turbos will make virtually no difference to your current setup. More lag for sure, but with the combination of cams maybe a little more top end should be possible. Just not worth it really... Link to comment Share on other sites More sharing options...
Recommended Posts
Please sign in to comment
You will be able to leave a comment after signing in
Sign In Now