Afshin Posted February 17, 2005 Share Posted February 17, 2005 My battle, like most l28et owners has been mild detonation as evident by that damn pinging around 4200 RPM (peak torque). In my attempt to reduce it I have switched to NGK 8 heat range plug after having used the BPR7’s which are already one step cooler than the factory BPR 6. The 8’s did help a little but also idle is a tad rougher as well, but still fine. I then made my fuel mixture richer to 10.5-11:1 in the 3750 to 4500 RPM range, which helped but still had pinging on hard runs. Then as per Bernard’s suggestion, I enrichened the mixture earlier from 3500 rpm to allow for enough time to cool the plugs/chamber and it definitely helped, but I still was having occasional brief pinging at times. Of note, my timing was already retarded to 18 under full load (in the 3500-4500 rpm range). Now I being in California, I am subject to the worst quality 91 octane gas (high in MBTE..), but I felt that something else might be off. I remembered reading that carbon build up in the chamber will retain heat and cause detonation. So, I got a can of the famous Seafoam fuel treatment and used 1/3 of a can straight into my intake manifold (via a vacuum line), let it sit for 10 min, restarted the car, smoked like mad, got dirty looks from the neighbors and then went out for a spin. It actually got rid of the brief pinging under heavy sustained load, which allowed me to turn the boost up more, until I heard some pinging and then backed off the boost a little. So now I can safely run sustained 12-13 psi (peak 14-15psi) with junk gas. BTW I had used other good quality carbon cleaners via the gas tank with no noticeable improvement. I never would have thought that carbon build up would have this much effect on detonation!!!! I’m on my way to the NAPA parts store to buy another can of seafoam. Also, I did all this testing within 5 days, so there were no other variables (same temperature, same gas, same road). And no, I have no stock in Seafoam or NAPA Quote Link to comment Share on other sites More sharing options...
mtcookson Posted February 17, 2005 Share Posted February 17, 2005 here's something interesting that boosted maxima guy did after reading an article in popular science: I read that article in Popular Science this past summer and tried a experiment on the kid's PW50. (two stroke motorcycle) did the same basic cuts discribed in the article and pictured above. It made some noticible power and kept the plug clean. The idea is that as the piston pushes the air/fuel mixture up towards the head the V grooves chanel the mixture being pushed on them into the center of the chamber and keep the mixture swirling/mixing instead of being stagnant out there sandwitched between a flat head surface and flat piston surface. The pistons build up is very light and only around the outside it came right of with two passes of steel wool. The article who was writen by a guy from Inda races but the only fuel they have there is 70 somthin octane! He would raise the compression in his engines but kept being limited because of detonation. These V grooves took away detonation with the same fuel so he could keep raising compression. It also improved gas milage and better emmisions. The grooves extend about a 1/8 before the edge of the head gasket. Ok... Got it going yesterday..> Fired right up on the first turn. Purged the coolant .. toped it off ect..> It took over 20 miles to clear all the excess coolant from the muffler and pipes.. What a mess. Anyway... Right from the start I could tell somthing was different. It Idled Rock Solid. I mean to the point that a glass of water would bairly shake. I could even turn it down under 500rpm and still get the same result. The guy In India reported the same thing.. very very achieveable low idle so much that you could count the (fan) blades on a cooling fan turn. I've got the same thing.... Quote Link to comment Share on other sites More sharing options...
CruxGNZ Posted February 17, 2005 Share Posted February 17, 2005 Now THAT'S interesting! I need to subscribe to Popular Science again. !M! Quote Link to comment Share on other sites More sharing options...
260ZRED Posted February 17, 2005 Share Posted February 17, 2005 Don't you have to take it in account that the material removed effectively LOWERED the compression ratio? Maybe that's why he could use higher octane fuel? Even 'simple' tricks like useing a physicly bigger spark plug can help to noticeably increase compression (heard this from my father, who used to built small mopeds and bikes when he was young. He would enlarge and re-thread the spark plug holes and use truck spark-plugs, for 4-5hp mopeds.) Anyway, I don't understand how those grooves could help anything..? As the fuel enters via the valve, it is already in the optimal position to be ignited, right? If not, how could something leading AWAY from the cumbustion chamber help anything???? I'd like to understand this more, it seems to be a really novel and interesting idea. Quote Link to comment Share on other sites More sharing options...
Guest 240zJake Posted February 17, 2005 Share Posted February 17, 2005 Such was the thinkking that made others think it would not work. I think that when the piston moves up on the compression stroke the air is forced to follow the grooves and blow across the sparkplug and also induce turbulence Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted February 17, 2005 Share Posted February 17, 2005 So someone try this on their Z and then let me know the results =) Quote Link to comment Share on other sites More sharing options...
Guest 240zJake Posted February 17, 2005 Share Posted February 17, 2005 Someone sends me a spare z head and I'll give it a go. Quote Link to comment Share on other sites More sharing options...
Guest tony78_280z Posted February 17, 2005 Share Posted February 17, 2005 *pats self down* ...I got a spare one around here someplace... Quote Link to comment Share on other sites More sharing options...
2126 Posted February 17, 2005 Share Posted February 17, 2005 Very interesting! One think to consider is the potential of creating a hot spot by adding the groves! I'm not suggesting this groving method does not do something to the swirling of the fuel/air mixture during the compression stroke and has been believed to have decreased detenation for someone, but if the groves were done in such a way as to leave pointy areas in the combustion chamber area (pointy spots are heated easier than a relatively flat area, typically left by most professional head modifying speciaists) you may just wind up making the detenation problem worse. Hot spots do attribute to detenation. You may ask yourself if any of the top head porting folks are using this method? Also, I agree that adding the groves will certainly decreases the compression ratio. One additional thought to consider...just because someone publishes something in a magazine such as Popular Mechanics does not not make it gospel. All to many times people read articles and without question accept it as the true! Hummmmmmmmmmm!!? Quote Link to comment Share on other sites More sharing options...
Cody 82 ZXT Posted February 17, 2005 Share Posted February 17, 2005 Ok so back to the orginal post.. I had good results using the NGK bpr7es plugs gapped and .025. I could run about 1 extra psi 15 to 16 and with some more fuel 17 to 18. Also I've used the Seafoam stuff before and had results with it also. Would recommed it to someone who wanted to clean out a dirty motor. Quote Link to comment Share on other sites More sharing options...
mtcookson Posted February 18, 2005 Share Posted February 18, 2005 Very interesting! One think to consider is the potential of creating a hot spot by adding the groves! I'm not suggesting this groving method does not do something to the swirling of the fuel/air mixture during the compression stroke and has been believed to have decreased detenation for someone, but if the groves were done in such a way as to leave pointy areas in the combustion chamber area (pointy spots are heated easier than a relatively flat area, typically left by most professional head modifying speciaists) you may just wind up making the detenation problem worse. Hot spots do attribute to detenation. You may ask yourself if any of the top head porting folks are using this method? Also, I agree that adding the groves will certainly decreases the compression ratio. One additional thought to consider...just because someone publishes something in a magazine such as Popular Mechanics does not not make it gospel. All to many times people read articles and without question accept it as the true! Hummmmmmmmmmm!!? yeah, i've heard of the pointy thing too. my guess on this is that since the grooves induce movement during compression compared to the mixture being stagnant, it allows them to cool off (or at the very least keeps the mixture from staying around hot spots in the cylinder). i should have reminded the guy to cc the heads to see how much of an increase there was, i didn't even think about it at the time. Quote Link to comment Share on other sites More sharing options...
Afshin Posted February 18, 2005 Author Share Posted February 18, 2005 Interesting article, however I think in light of all the R&D that goes into producing swirl and proper air flow in the design process of a head and all the various form and flows in different heads, such a one step design for all chambers may be risky. You figure it would have different effect at different speeds, volume, pressure, possibly affect airflow in undesirable way during intake or exhaust stroke.... Nevertheless, may be worth trying if someone has the extra time, head and is adventurous....I also think the edges of the grove would have to be somewhat rounded to minimize hot spots as already discussed. On the more practical aspect, I boosted my octane to about 93 and then was able to advance timing by 2 degrees and turned up the boost to 13-14 psi range with good success (or 16 psi on my second gauge, I rather go with the more conservative reading). This is a little better than the rule of thumb would predict for a 2 octane gain, but I think that 91 is just too low for high boost (and to believe that I figured that one out all by myself). Well at least I will be leaving CA this summer and will then have access to 93-94 octane at every pump So Cody, you prefer the plugs at .025 gap ? How is the idle, was it missing with larger gaps or did you just try 0.025 based on the amount of boost and stuck with it because it worked well....I run at .035 with a MSD box, I have not tried anything below .032 260ZRED, regarding lower compression from removing the carbon, I doubt that such a thin layer would have such a dramatic effect (though it may still play a role). Detonation because of heat retention seems to be a well described phenomenon, I just was not expecting so much improvement. Quote Link to comment Share on other sites More sharing options...
mtcookson Posted February 18, 2005 Share Posted February 18, 2005 Interesting article, however I think in light of all the R&D that goes into producing swirl and proper air flow in the design process of a head and all the various form and flows in different heads, such a one step design for all chambers may be risky. You figure it would have different effect at different speeds, volume, pressure, possibly affect airflow in undesirable way during intake or exhaust stroke.... Nevertheless, may be worth trying if someone has the extra time, head and is adventurous....I also think the edges of the grove would have to be somewhat rounded to minimize hot spots as already discussed. that things that i quoted is from a guy that's on a maxima forum i'm on. he tried it on his maxima engine while the heads were off and so far everything seems good. i'll keep tabs on it and see how the long term effects are. he did say the idling got a lot better as the article said would happen and he also said his car has never ran better... so, so far it seems its working out really well. i guess time will tell. Quote Link to comment Share on other sites More sharing options...
NickandM 72 240Z Posted August 5, 2008 Share Posted August 5, 2008 Hey guys, Thought I'd revive this long forgotten thread. I came across this thread about about 6 months ago and it really got me curious, to the point where I couldn't sleep at night with my brain going a million miles an hour thinking about the differant ways to do these strange grooves. So I finally found this thread again, then looked up popular science, found the article on their web site and had a good read. (if anyones interested here's the link, great story http://www.popsci.com/cars/article/2004-09/obsession-mr-singhs-search-holy-grail ) Halfway through the article it talks about how he patented this idea and gives you the patent number, so I then looked up the US Patent Office, did a quick seach by patent number and whahlaa, some of his drawings are there and a full explination of how this design works. Anyway I couldn't believe my luck at actually finding what I needed on the net, so the punchline to this story is that I took the head off my L18 yesterday to do some minor port work and replace the timing chain but now I'm going to try this idea out and see what differance it makes. For anyone who's interested keep an eye on this thread, I will post pics and do a write up of how the 510 goes after this mod. Cheers. Nick Quote Link to comment Share on other sites More sharing options...
Careless Posted August 5, 2008 Share Posted August 5, 2008 he has a website now! this is cool stuff! http://www.somender-singh.com/ Quote Link to comment Share on other sites More sharing options...
Noddle Posted August 7, 2008 Share Posted August 7, 2008 anyone tried this on the "L" type engines ? I would love to see before and after results (since this is something that anyone could do) Nigel Quote Link to comment Share on other sites More sharing options...
Guest JLT Posted August 7, 2008 Share Posted August 7, 2008 You should talk to these people, they have plenty of experience... http://forums.turbobricks.com/showthread.php?t=66779&page=37 I would love to see before and after results (since this is something that anyone could do) Nigel http://www.herningg.com/singh/Engine%20Running%20Tests%20Analysis.pdf Quote Link to comment Share on other sites More sharing options...
rsicard Posted April 1, 2009 Share Posted April 1, 2009 You should talk to these people, they have plenty of experience... http://forums.turbobricks.com/showthread.php?t=66779&page=37 http://www.herningg.com/singh/Engine%20Running%20Tests%20Analysis.pdf JLT: Thanks ever so much. You have opened another VERY good door of experience and knowledge concerning usage of grooves. I have run into one of these fellows posting on Turbobrick before. He appears to be the most experienced in grooves. Quote Link to comment Share on other sites More sharing options...
boardkid280z Posted April 1, 2009 Share Posted April 1, 2009 So, grooves, anyone, anyone? Seriously though, that PDF shows CLEAR results of a definitive improvement in efficiency, fuel consumption, and more importantly, BOTH horsepower AND torque from simple grooves. No reason this shouldn't translate into our motors. Has anyone done this?? As I was reading about it and seeing pictures, I was wondering if these mods are mainly beneficial for motors with flattop pistons since these have the quench design and really make use of it. Would there not be a noticeable effect on a dished piston motor, like most of our turbo motors? Or would there still be a similar benefit? Quote Link to comment Share on other sites More sharing options...
Pyro Posted April 7, 2009 Share Posted April 7, 2009 try a bigger cam. longer duration on the intake valve will lower cylinder pressure. try a NA cam. has 8 more degrees on the intake. or try a msa stage 1 turbo cam which has 20 more degrees. Quote Link to comment Share on other sites More sharing options...
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