Memph Posted August 17, 2006 Share Posted August 17, 2006 I understand the disadvantages in having injectors that are too small. But so far the only negative towards bigger injectors is cost. and as stated previously the difference between 550cc and 740cc injectors is only around 50 bucks. Which brings me to the question. Can i have injectors that are too big? advantages/disadvantages. Cheers guys. Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2417223 Share on other sites More sharing options...
R31Nismoid Posted August 17, 2006 Share Posted August 17, 2006 Fuel economy decreases generally speaking the larger you go. Being it is hard to get larger injectors to behave like smaller ones on idle etc. i've moved back to 550's with my RB26... so we'll see if there is a larger difference. That said, with 740's i still managed around 350km to a tank For me, that was pretty good Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2417229 Share on other sites More sharing options...
Memph Posted August 17, 2006 Share Posted August 17, 2006 so assuming both cars in question have (say) 250rwkw though one has 740's and the other has 550's both are tuned fine. Would economy be similar for the two? Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2417233 Share on other sites More sharing options...
rs73 Posted August 17, 2006 Share Posted August 17, 2006 For a mild street tune has anyone tried upgrading stock R33 injectors with a JDM spec S15 injectors rated at 480cc/min? Will those injectors fit straight away without any mods? The problem is most package are sold in set of 4, so either you buy 1 set and then hunt the remaining 2 or buy 2 sets and try to sell the spare 2. Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2417394 Share on other sites More sharing options...
Sydneykid Posted August 17, 2006 Share Posted August 17, 2006 I understand the disadvantages in having injectors that are too small.But so far the only negative towards bigger injectors is cost. and as stated previously the difference between 550cc and 740cc injectors is only around 50 bucks. Which brings me to the question. Can i have injectors that are too big? advantages/disadvantages. Cheers guys. Let me start of by stating that I am not the world’s best tuner, far from it. With that out of the way, I always find it harder (more time consuming) to tune a car with larger than necessary injectors. That means slightly higher tuning costs, if I was doing it (not that you would want that) . Secondly, all injectors are not the same flow rate, commonly you will find 1.5% to 3% variation in their individual flow rates. I find larger injectors are at the higher end of the scale. So 3% of 740 cc’s is a lot more than 1.5% of 550 cc’s. You have to tune for this larger variation between cylinders. That’s a little more time on dyno. All together, the above may not amount to much extra $cost. But it is worth keeping in mind. cheers PS; I have seen a standard Power FC handle 1100 cc injectors easily. After you shoot the guy that told you otherwise, hang him just to make sure he can’t spread that crap any more.. Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2417398 Share on other sites More sharing options...
Sydneykid Posted August 17, 2006 Share Posted August 17, 2006 For a mild street tune has anyone tried upgrading stock R33 injectors with a JDM spec S15 injectors rated at 480cc/min? Will those injectors fit straight away without any mods?The problem is most package are sold in set of 4, so either you buy 1 set and then hunt the remaining 2 or buy 2 sets and try to sell the spare 2. Yep they work just fine, last time I did it I bought 3 sets (of 4) and did 2 cars. Keep in mind that it is only the JDM S15 manuals that have the 480 cc injectors. Not all S15’s. Cheers Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2417408 Share on other sites More sharing options...
rs73 Posted August 17, 2006 Share Posted August 17, 2006 Yep they work just fine, last time I did it I bought 3 sets (of 4) and did 2 cars.Keep in mind that it is only the JDM S15 manuals that have the 480 cc injectors. Not all S15’s. Cheers Is there a way to quickly differentiate these 480cc injectors from the non-JDM local ones? e.g. colours? Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2417445 Share on other sites More sharing options...
Evasion Posted August 17, 2006 Share Posted August 17, 2006 ^^^^^^^ And how much power do they support or how much extra could you push after changing stocko's to them. Thanks Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2418729 Share on other sites More sharing options...
Shaneo Posted August 18, 2006 Author Share Posted August 18, 2006 my calcs put 480cc at around 250kw at the flywheel Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2419789 Share on other sites More sharing options...
Sydneykid Posted August 18, 2006 Share Posted August 18, 2006 480 cc = 480 bhp (in a 6 cylinder) 480 bhp / 1.34 = 358 kw 358 kw - 65 rwkw losses = 293 rwkw. We have actualy snuck 315 rwkw, but with slightly higher than standard fuel pressure. cheers Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420057 Share on other sites More sharing options...
rs73 Posted August 18, 2006 Share Posted August 18, 2006 With that quick calculation does it mean that a std 370cc RB25 injectors will support up to 370BHP or 276kw at flywheel or about 211rwkw? I've got my stock AFM maxing out a bit early at 206rwkw, and without upgrading any injectors except a Z32 AFM, I'd probably only get another 5kw or so for my $400? Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420175 Share on other sites More sharing options...
r33_racer Posted August 18, 2006 Share Posted August 18, 2006 Yeh those figures add up right. However, if you wanted to cheat as SK has said before you can raise the fuel pressure and squeeze more out of them after you change the afm, most ive heard out of std injectors is about 230rwkw...but i would say give or take 10rwkws for dyno differences. As some people have said more (upto 240rwkw) and some have said a little less (220 odd). Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420199 Share on other sites More sharing options...
rs73 Posted August 18, 2006 Share Posted August 18, 2006 Thanks... I think the FPR one is a cheaper way to get more power. I'll see how it goes after it's tuned tomorrow. If not, then forking out a little bit extra on the S15 ones seems like the best path for my small HKS2535, as with its power rating of I feel getting a Nismo 555cc injectors are way overkill. Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420227 Share on other sites More sharing options...
Munna1 Posted August 18, 2006 Share Posted August 18, 2006 Is there a way to quickly differentiate these 480cc injectors from the non-JDM local ones? e.g. colours? maroon = 480cc, purple = 370cc. http://www.nissansilvia.biz/sr20_types.htm Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420310 Share on other sites More sharing options...
Topaz Posted August 18, 2006 Share Posted August 18, 2006 I have purple top Nismo injectors and wondering what they actually are? They arent 370's are they? because I ordered 600's..... Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420340 Share on other sites More sharing options...
rs73 Posted August 18, 2006 Share Posted August 18, 2006 Those are aftermarkets, they have of course different colour coding than the OEM factory ones. For Nismo brand, 555cc is yellow, 600cc is purple, and 740cc is red. Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420370 Share on other sites More sharing options...
Topaz Posted August 18, 2006 Share Posted August 18, 2006 Those are aftermarkets, they have of course different colour coding than the OEM factory ones. For Nismo brand, 555cc is yellow, 600cc is purple, and 740cc is red. Ok good, I havent been able to find any Nismo colour meaning, thanks Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2420390 Share on other sites More sharing options...
mickr33 Posted August 19, 2006 Share Posted August 19, 2006 Hi people. What about some other brand apart from Nismo, Sard etc. Was wondering if Bosch do a replacement injector. Does anyone know if Bosch do and if so are they heaps cheaper, about the same, good or shite. Link to comment https://www.sau.com.au/forums/topic/130304-fuel-injectors/page/2/#findComment-2422279 Share on other sites More sharing options...
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