This can and is used by quite a lot of track cars. So yes it can help quite a lot. Its paticularly helpful when you have a high capacity fuel pump which circulates quite a lot of fuel out and through the surge tank. The surge tank can be a bit of a heat repository seeing the fuel return goes back into it. Any heat picked up in the fuel rail and the fuels trip around the piping tends to continually reheat the fuel as it goes around and around. A fuel cooler is a very good idea in this case
FFS Mate I've NEVER poured boiling water down my throat But I KNOW the result wouldn't be good....... Anyone with half a gram of knowledge about thermal transfer can see that the 300* rails pictured in this thread are gonna get hotter than the drilled out OEM ones, and that's not good..... FFS stop sooking and accept the obvious
I respect your personal opinion, but that's all it is, and as I suspected you have never used parallel fed rails let alone the 300deg rails. In fact when you saw the fuel temperature rise you were somewhere in Texas in 100deg heat with serial fed stock rails, thats a long a long way from the milder climate of Canada. You might also like to take into account the boiling point of different octane rated fuels. At atmospheric pressure, it's between 100F-38c and 400F-204c, the primary cause of this wide variance is the various additives in the gasoline from different refiners designed to meet different octane requirements. Fact, 94% octane fuel will boil before 98% octane, you were using 94% octane, in 100deg heat, what did you expect. Where are all the cases of heat soak affecting the 300deg rail, a lot of people use them, and not one case of heat soak affecting the rails is recorded anywhere. People should remember the difference in clearance between the two types of rails is 3mm. Oh and last but not least, "the $$ saved is a great caveat" there are no dollars saved in your case, the shop would have had to dissemble half the engine to machine the lower plenum to except the later model rails.
I agree that the 300' alloy fuel rails will experience heat soak and absorb radiant heat from its surroundings. Alloy's thermal conductivity is radically higher that iron (ever seen a steel finned heatsink, intercooler or radiator?). It will absorb the radiant heat faster, transfering it to the coolest item (heat travels from HOT to COLD), which may well be the fuel. And a small plastic insulator/spacer, in close proximity, might prevent a very, very small heat transfer barrier, though I doubt it would be a lot compared to the radiation and limited airflow. Think about the indesputable facts of physics and thermodynamics. The factory rail wins hands down in lower thermal pickup - and they're bad enough in the first place. Mounting is more suitable with the small tags furnace brazed into place. Also (whether this is a bonus or not) there's going to be more airflow around the factory rail. The lower intake manifold generally will be at a higher temperature (closer to coolant temps) than the air surrounding it (air's quite an effective insulator) Did anyone think WHY Nissan went to side feed rather than TOP feed ?? Its try and keep the injector COOLER to prevent in field failures which plagued earlier VG30's. The heat's got to go somewhere, into the fuel isn't a great idea either as it will change its density (although a small amount), make it boil at a lower temperature and degrade its stability. It's measureable none the less. The fuel temp sensor is used by the ECU to control fuel pressure when the engine is HOT to prevent percolation and poor hot starting/running. I've investigated the factory source code of VG roms with this system.
Geoff I purposefully gave you a complete background of the composition of my Z and how this oem fuel rail mod would best be applied to my case. Being quite knowledgable as you are about the Zed's I'm sure you must be aware that my lower plenum had to have been machined as part of the big HP build. I would have thought that would have been a given, at least for you. At any rate it is/has been done. For the 3rd time, I used the Texas example as a measuring tool for my purposes as a benchmark to reflect upon in the future. It was a learning part for me to actually visualize the the wide scope of fuel temps that I experienced real time via my PPC and ECUTalk. It gave me pause to consider. That consideration and pause is now revealing it's worth as I look to a fuel rail alternative. The numerous posts emphasizing the likelihood of substantial heat soak from a 300* rail over an oem is quite conclusive - to me at least. Will those that already have the 300* rail ever admit that perhaps they made a poor decision because of the associated rise in fuel temps? Perhaps not and most likely not as for most it would be too embarrassing to admit publicly. Do many if any know if their fuel temps have risen due to the install of a 300* rail? Probably not, if they don't take the time to utilize a datascan, ECUTalk or whichever. Or if they don'y have a real time monitoring system like I do. Will the extra heat soak compromise their performance? Perhaps so, but again we may never know as they themselves may never know why. Of course the 3mm would make a difference. Any distance achieved from the plenum = less chance of heat soak. I'm not an engineer and don't have to be to recognise something like that. Geoff, does not the multiple posts from other members on the 300* rail's potential heat soak not make any sense to you? Is your fervour due mostly because you already have 300* rail in place already? I know I would be a bit pissed in paying big $$ for something like that only to find out later that perhaps it may not have been the best choice or approach for fuel delivery. You never did answer a previous question I posed. With the numerous statistics posted of the effectiveness of the 300* rails not once is the fuel temp issue mentioned. There's all sorts of colour pics depicting better flow etc and numbers for this and that but nowhere is it mentioned about fuel temps. Do you not think that perhaps something was amiss there. At least if the subject was mentioned in passing than the makers would have acknowledged the value of fuel temps in the big picture, but they didn't. Since this subject has gained so much interest in this thread, have you tried to source some info regarding this from the 300* makers? If so, I'd very much like to know what their official position is on the subject. They seem to be very precise in everything regarding that product so I'm sure that data is readily available. Looking forward to hearing what the 300* folk have to say on this. Thank you for that.
Thanks for your reply John, and let me say this. I'm in no hurry to prove or disprove anyone's speculative musings on the 300deg rails including mine,so unless someone/anyone has solid evidence that these rails adversely affect (through heat soak) fuel delivery in any way that is not comparable to the stock rails under the same conditions, my view point will remain the same. As other knowledgeable members have rightly pointed out there is a difference in clearance between the lower plenum,the stock rails and the 300deg rails, that difference is 3mm. That 3mm difference seems to have clinched it in favour of the stock rails for some, I'm not convinced for this reason, because to be effective the gap between the rail and the plenum would have to be quite a bit bigger, anything under 18mm or 3/4'' is useless, you only have to look at exhaust heat shield technology to realise anything under 18mm dose not allow enough air circulation between what ever is being cooled and the source of the heat to carry the heat away, simple as that. Also the material the 300deg rails are made from has been brought into question, yes alloy will absorb radiated heat at a higher/faster rate than steel, but alloy also dissipates that heat quicker that steel dependant on the material gauge used, which brings me to my last point, smic's as opposed to fmic's and engine running temperatures. Its well documented round here that I believe an fmic contributes to higher engine running temperatures (by how much is the only question imo) it stands to reason that blocking air flow to the radiator has that effect, but also buy restricting the air flow through the radiator the engine bay will also cop a rise in temperature, because air speed through the radiator has been slowed down it takes the heated air inside the engine bay longer to exit out through the tunnel, dose it affect the overall running temperature of the engine? I would say yes, but by how much I don't know.There's a lot off people out in zed land using fmic's that have seen for themselves a rise in engine temperature directly after an fmic was installed its well documented, but did it affect the overall performance of the engine, they say no it didn't and have a shiny new trick radiator to prove it. The point is I expect my engine will run at normal operating temperature most of the time 85-90c, the occasional blast down the 1/4 may see a rise in temperature say 95c, will that be enough to vaporise or boil the fuel in 300deg rails, I doubt it because I've seen a 300deg rail equipped zed sitting on a dyno without any fans in sight pumping out over 500whp on the 3rd pull without any fuel related issues at all, the drop in boost at the end was a ebc fine tuning issue. Hope you don't mind my using your sheet Chris.
I reckon it will be 3-6 times worse than the stock rail just going off the thermal conductivity of the ally vs the steel. But 3-6 times worse is a bit useless, 6 times more heat isn't 6 times the temperature. Is it enough to matter? Maybe, maybe not. (I wonder why it's called a 300deg rail? lol!) I don't think it will have any major issues, it shuoldn't get over 90deg and it will be under pressure when in the rail, if it vapourises a bit on the way back to the tank it will still work fine. If you have a surge tank I would definately looking into a cooler for it. Geoff make sure you let us know how the fuel temps go once she's all up and working properly.
Kudos to you Geoff for sticking to your guns (so to speak). I believe I get the jist of what your saying and I have nothing to really contradict it other than to say that what appears to me is that - "If I don't experience any problems than there must not be any problems". I'm afraid I wouldn't want to subscribe to that sort of an approach. Just a little too risky for my pocket book. I tried to make a post on an old related 3ZC thread looking for imperical data on the 300* rail insulators but it was deleted and the thread unfortunately locked. I even asked you if you had any data pertaining to changes in fuel temps from a before/after perspective and there still isn't any. In the absence of imperical data, one can only utilize their common sense. In keeping with that, common sense would say the more removed or insulated the rail can be from the lower plenum, the better. Would you not agree? Or, would you have to wait to that fatefull point where fuel temps reached a critical point to finally say something to the contrary? Just because it didn't go boom is by no measure an indication of it's capability to minimize fuel temps. That's living on the edge I wouldn't want to do. I'm sure there must be some data somewhere that the 300* people have that reflects before/after fuel temps since they seemed to have covered every other aspect that would come into play during their R&D.
You can be sure I will Chris. Geoff make sure you let us know how the fuel temps go once she's all up and working properly.
Ok John, here's an idea, why don't you post something on 300zxclub.com, there's a vast membership their, and surly some of them must use and have an opinion on the 3000deg rails
^^^ That's good to hear Rob. Since you're a 300* fuel rail owner perhaps you can share what the 300* R&D results were for their fuel temps - before / after?
What else do you need to know John, 626rwhp no issue, 504rwhp no issue, and not one complaint throughout the whole zed community, world wide(that I can find) regarding heat soak fuel related problems with the 3000deg rail. I could be wrong, but dose the word agenda have a meaning in this debate.
Wouldn't have a clue and I don't know any other manufacturers that offer this comparison.... I know they fit well and they work... no fuel issues making bucket loads of power on pump fuel.
