Quote:
Originally Posted by AndyBRZ
I am glad I helped you. The hood louvers work very well. There are several kinds but some of them are way better than others but even with good hood louvers you will get misfire codes if you have "issues" down there. I will try to explain. The stock headers are very well insulated but they still carry tons of heat and the proof of that is your P0351 code which is your passenger front cylinder which is right under the coil for spark 1. The radiant heat is brutal and it is probably setting off the code. I have tried also heat tape in top of the coil pack but I personally think it is a waste of time. I have custom built equal length headers that I Swayne coated inside and out. This is the best thing you can do to dissipate heat in the engine compartment and in my case, it works very well. After a hot track session you can literally touch my header with your hand. Unfortunately I was getting P0353 which is the passenger rear and the reason for it was that the short exhaust pipe that connects the header to the cat-back was super hot and radiant heat was killing #3 coil.
If you add these external heat sources to the potential heat produced by leaky direct injectors on any given cylinder you have a real mess of heat everywhere in the side of the motor there that all of it is conducive to misfire codes and regardless of hood louvers, they will come out and show their ugly face.
I would say that if you get more misfires after you do the coilpacks and the DI injectors, it is worth to replace the factory fuel pump with a DWXXX.
If you replace the fuel pump you should add the fuel trap door so you do not starve it from fuel on left turns.
The fuel pump will ensure fuel feed to the high pressure pump and help avoiding the firecrackers.
I am personally still playing with all of these variables and for sure I will know more in a few weeks. I am changing all my DI seals, spark plugs and adding a DW fuel pump next weekend. I have a full calendar of track events this year so I will update as I go, specially if I finally get rid of misfire codes and firecrackers. I hope so because if I don't I am going to seriously consider either removing DI system or maybe a sensible engine swap with something less sophisticated but far more reliable, in the H configuration of course.
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Update 7 months later and a full track season behind since I posted the firecracker shenanigans. Zero issues with firecracker noises and zero codes. In several events we even double stinted the car all weekend long.
I ended up removing the high pressure fuel system and found 1 direct injector (#3) flowing 15% more fuel than the other 3 injectors so I replaced it. The body of the injector looked burnt as hell. I looked at the pistons with a boroscope and everything looks good but #3 looks suspicious with a small nick in the top of the piston bowl but since it is not using oil I did not even bother to check compression or leak down. It may be down a hair in power but I do not really care as I am going to rebuild the motor soon with better rotating parts and blue print it for added reliability. This factory motor has 26k track miles and I think it owes me nothing.
To the high pressure fuel system, all the DI seals were questionable or almost disintegrated so I replaced them all along with the one injector and all the HP lines.
I also removed the flex fuel E85 system. I tested several times between different pumps e85 fuel (More like E5X'sh, E6X'sh) versus good 93 and the lap times difference were close to nothing where getting e85 in some tracks is a royal PITA.
Totally not worth the extra work and I am not going to buy drum E85. I ran only 93 gas and re-instated my secondary lambda (Even passed emissions in IL with a full cage and gutted BRZ so I can still drive it to the gas station).
I also insulated the exhaust very well under the ECU, cylinder 3 and starter area. Installed heat blankets around the header connection pipe located in that area. No more heat issues either and the started does not get hot anymore.
I hope this helps.