JamieP Posted May 24, 2010 Share Posted May 24, 2010 Titan do some nice 272 cams for the VVTI, id go with them, infact i might well do that for the 3.4 build next year. Quote Link to comment Share on other sites More sharing options...
johnny g Posted May 24, 2010 Share Posted May 24, 2010 With the demise of the MR2, I'm really stuck at what to do now. A 3.4 VVTi does seem nice Quote Link to comment Share on other sites More sharing options...
JamieP Posted May 24, 2010 Share Posted May 24, 2010 With the demise of the MR2, I'm really stuck at what to do now. A 3.4 VVTi does seem nice With a GT47-80 strapped to the side it sounds about perfect:cool: Quote Link to comment Share on other sites More sharing options...
ray007 Posted May 24, 2010 Author Share Posted May 24, 2010 On a VVTi though, the range of cams is limited for the intake, that's the reason for asking thanks, this was gana be my next question Quote Link to comment Share on other sites More sharing options...
ray007 Posted June 2, 2010 Author Share Posted June 2, 2010 Both of these are side feed/high impedance and will fit the stock rail. SH650A Power Enterprise Fuel Injectors 650cc 63561 SARD Fuel Injectors 650cc ive googled these injectors and some sites say they are not suitable for a VVti? Any ideas? Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted June 2, 2010 Share Posted June 2, 2010 I've personally fitted Power Enterprise 650 injectors into 3 vvti Supra's without any issue. Quote Link to comment Share on other sites More sharing options...
ray007 Posted June 2, 2010 Author Share Posted June 2, 2010 I've personally fitted Power Enterprise 650 injectors into 3 vvti Supra's without any issue. glad to hear that.. what turbos did you use Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted June 2, 2010 Share Posted June 2, 2010 Crikey... It was about 5 years ago... Hmmm, a GT35R, and two T61's IIRC. Quote Link to comment Share on other sites More sharing options...
ray007 Posted June 2, 2010 Author Share Posted June 2, 2010 Crikey... It was about 5 years ago... Hmmm, a GT35R, and two T61's IIRC. and with the T61, did you stick to stock cams? if so what kinda bhp did you get? Quote Link to comment Share on other sites More sharing options...
Matt Harwood Posted June 2, 2010 Share Posted June 2, 2010 Yep, stock cams on all three. I'm not sure any of them were dyno'd at the time... Circa 500 @ 1.4-1.6 bar I would guess... Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted June 2, 2010 Share Posted June 2, 2010 Mine did 512bhp at SRR with stock cams at 1.4-1.5 bar ish. Quote Link to comment Share on other sites More sharing options...
ray007 Posted June 3, 2010 Author Share Posted June 3, 2010 Mine did 512bhp at SRR with stock cams at 1.4-1.5 bar ish. and was that with 650cc injectors or 550cc? Quote Link to comment Share on other sites More sharing options...
Gaz6002 Posted June 3, 2010 Share Posted June 3, 2010 and was that with 650cc injectors or 550cc? 850cc... but I was talking about the cams matey, they'll be good with that turbo. Quote Link to comment Share on other sites More sharing options...
ray007 Posted June 3, 2010 Author Share Posted June 3, 2010 850cc... but I was talking about the cams matey, they'll be good with that turbo. yeh i know - was just wondering if it is really worth upgrading to 650cc when im on stock cams? Quote Link to comment Share on other sites More sharing options...
foodfreak Posted June 4, 2010 Share Posted June 4, 2010 Mine is one of the VVti's that Matt fitted with PE 650's. blimey:blink: that was nearly 5 years ago! single walbro Stock cams- 530 bhp on the T61.....haven't had the Billet 6262 dyno'ed yet, but bum dyno tells me it's stronger Quote Link to comment Share on other sites More sharing options...
TLicense Posted June 4, 2010 Share Posted June 4, 2010 I don't think anyone has really found out how much 550cc injectors can actually take. The amount of fuel an injector can flow is defined by 2 limits. How fast they can open and close fully, and at what pressure they can open and close fully at. As you increase revs / boost the amount of time the injector is open for is increased by the ECU. At a certain point the injector is open for so long that the solenoid can't react quickly enough to close it at the end of one cycle and open it at the start of the next. At this point the injector basically becomes static. The generally accepted maximum safe duty cycle (ie the percentage of a full 4 stroke cycle the injector is open for ) is 80%. However, fuel flow through the injector is also determined by the pressure differential across the nozzle opening which is controled by the fuel pressure regulator. If the pressure differential is inceased so will the amount of fuel flowing. However you can't just increase the pressure infinitely, as the when the solenoid tries to open, it is pushing the pintle against the pressure differential. The solenoid has only so much "strength" so if you increase the pressure too much the injector can effectively end up pinned shut. The stock fuel pressure differential is set by the fuel pressure regulator at between 33 - 40 PSI. The ECU takes care of the variation in pressure by adjusting the duty cycle (from information from the O2 sensor). But if you replace the stock regulator, with one that you can adjust the pressure, you could potentially increase this pressure up to the point where the solenoid is overwhelmed. There is one other problem, in that the fuel spray pattern can be largely effected by the pressure differential, so it may be that this becomes the limiting factor before the solenoid becomes overwhelmed. I don't know if anyone has actually flow tested the stock injectors (either 440 or 550cc) at varying fuel pressures to see at what pressure they do actually supply the amount of fuel they're labelled as doing. I would hazard a guess and say not. But it's quite possible if at say, 36 PSI they flow 550cc, you could potentially crank up the base pressure to say 45 PSI and you would effectively end up with larger injectors. (I don't recommend doing this unless you've had the injectors flow tested to ensure a) the solenoid can handle the increased pressure and b) the spray pattern is still good at the increased pressure). Quite interestingly, there is no single industry standard as to what pressure injectors are flow tested at. So if someone is selling say 650cc injectors, it's important to find out at what pressure, duty cycle and RPM they were tested at. As each of these will have a massive effect. Quote Link to comment Share on other sites More sharing options...
bignum Posted June 4, 2010 Share Posted June 4, 2010 Nice explanation tony. Quote Link to comment Share on other sites More sharing options...
Wez Posted June 4, 2010 Share Posted June 4, 2010 Quite interestingly, there is no single industry standard as to what pressure injectors are flow tested at. So if someone is selling say 650cc injectors, it's important to find out at what pressure, duty cycle and RPM they were tested at. As each of these will have a massive effect. Great write up Tony. Just to add to your last point, there is also no standard on what fluid is used to define the flow rate, this came to light when some companies were claiming increased flow numbers but were actually using a more viscous fluid Quote Link to comment Share on other sites More sharing options...
SupraTTBPU Posted June 18, 2010 Share Posted June 18, 2010 Where did u get your drop in injectors ? cheers Quote Link to comment Share on other sites More sharing options...
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