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240Z Turbo

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  1. The boost fluctuation sounds like an issue with your duty cycle of the closed loop feedback on your boost controller assuming it is controlled by the MS. Without knowing how or what you use for a boost controller hard to exactly know what is happening. Regarding the dwell and voltage, the spark energy will be a function of both dwell time and battery voltage so a lot of systems have a 3D map to account for both variables. I run the Bosch P100-T coils in the link below and going from 14V down to 12V requires ~0.9ms of additional dwell to achieve equivalent spark energy. https://www.fin
  2. Other's have asked what coils you are running and this is important since you run the MegaSquirt. You need to know the dwell time vs spark energy of your specific coil so you can input the appropriate dwell times in your software. Too little dwell can result in too little spark energy. Gapping down to 0.020" is not uncommon for high boost applications, but with a good coil setup no reason you can't run much higher.
  3. OK, good luck and do the intercooler when you can because you should be able to run 19-21psi on 93pump if you turbo is efficient at those pressure ratio's.
  4. Pin hole leaks are just a nuisance and likely don't affect your issue, but good to get them sealed. If you have boost creep then it would indicated you need to port the wastegate hole on the turbine housing to increase flow. Post up your actual log file and I will take a look using LogViewer and post the graphs. Regarding IAT, strive to be within 20F of ambient so if you are seeing 50F above ambient then likely your intercooler sucks. Garrett 24x12x3.5" core works exceptionally well and I see less than 20F over ambient at 34psi in the summer.
  5. GEN I GTX3582R vs S362 SX-E spool up on the street. The dyno does not load the engine as much so that affects the spool of the 68mm turbine wheel in the S362, but on the street I have countless logs showing it spools the same.
  6. I know it is easier said than done, but you need to think about having someone fabricate a twinscroll manifold for your setup. The open scroll is great for a drag car, but in my experience it sucks for a street car because of spool. Below is an example on my EVO from back in 2011 when I was running a GTX3076r. I had a cast manifold using a T3 open scroll housing, 0.63 vs 0.82, and then I fabricated a twin scroll manifold and went to a1.06 a/r T4 twin scroll. The twin scroll crushed the open scroll in spool and made the same power on the topend, but killed the open scroll torque everywhere.
  7. Rule of thumb I use is multiple engine hp you want to support and multiply by 1.5 to get CFM needed. If you call K&N they will give you the CFM rating of a filter at standard pressure drop (can't remember what that drop is). So, if you want to support 500hp@engine then get a filter that flows 750cfm at standard pressure drop. I like running larger inlet filters and use a velocity stack. You can run a filter smaller than what I recommended, but this will only increase the pressure drop across the filter.
  8. Primary cats are typically within 12" of the turbo, but secondary cats are usually much farther, perhaps 24-36" post turbo so putting it by the transmission should be ok. You can add the resonator either before or after the CAT so whichever position is most easy to integrate. On the GTR most people run the CATs on the midpipe and ditch the primary CATs, which is very similar to what you are proposing. On my GTR I used an XFORCE 100 cell CAT (XForce CAT12-350(100)) with my 3.5" piping, but they make an equivalent diameter CAT for 3" inlet/outlet. CAT only cost me ~5hp at ~825hp
  9. I think you will be fine either way, but if packaging is an issue you at least have piece of mind that 2.25" will support the necessary flow without excessive drag based on the guidelines provided by Corky Bell.
  10. Just be careful as the holes in the front radiator support where you run the IC piping vary from year to year. Specifically, their location slightly changes depending on the year of your car. I learned this the hard way when I used to fabricate intercoolers for the Z.
  11. In theory you want the post IC piping to be smaller and obviously, the pre intercooler piping would be larger. The air from the turbo to the intercooler will be less dense as it is significantly hotter and thereby requires more volume due to the decreased density. Once the charge goes through the intercooler it is cooler and therefore more dense requiring less piping size for a given mass of air. On the GTR we see the turbo to intercooler piping is 2.75" and intercooler to TB piping is mostly 2.50". With that said, I run 2.75" on my GTR for all piping, largely because I run a blow through
  12. Your adapter for the wastegate looks great and you did a very nice job on the downpipe. Since your graph lines up almost exactly until you hit a certain RPM it would seem to indicate a restriction or a boost leak. What doesn't make sense is that you car won't make additional boost and we know the pressure is created because of the resistance to flow (restriction). A turbo speed sensor would definitely give you a better sense of these issues as well as the ability to measure EGBP before/after the turbo. I see you run the Tech 3, do you have any spare analogue inputs? Coming from
  13. Just so you know I have my GTX3576r on the shelf and plan on running it when I start building the 71 240Z I purchased last year. Just saying that I don't perceive any issues with that turbo making power on an L-series motor. 500hp@wheels feels quick and 573@wheels pulls really strong, but no issue to control as the car is AWD. I have to say it is fun jamming the gears at that power level and revving the engine to 9K. When you do the 2-3 shift the car still pulls like a freight train in 3rd gear with no signs of slowing. Haven't run the GTX3582r past 34psi on pump 93 yet so I do
  14. doubtful your surging on this turbo and not hearing or feeling it. The surge ports don't work well on that turbo and it would be audible as well as show up in the dyno graph. Having run the GTX3076r, GTX3576r, and GTX3582r(current) on my 2L EVO it definitely seems something is off with your setup. You would need to stick a speed sensor on the turbo to understand where you are on the map and it would also answer any doubt about surge. On the GTX3576r I made 505hp@wheels 33psi tapering to 31psi on 93 pump and 1.01ar Vband TS, 460hp@wheels 30psi on 93 pump and 1.06ar T4 TS, and 573hp@wheels 3
  15. As a rule of thumb the filter flow, in cfm at standard pressure drop, should be ~1.5x the hp it is supporting. This means for 500hp you want a filter to flow 750cfm. That doesn't mean you can't make the same hp with a smaller filter, but you will have a higher pressure drop. Whether turbo or NA, pumps don't like restrictions on the suction side. K&N doesn't list flow numbers on their site, but if you call they will provide.
  16. As previously stated, you "cut down the backside of the outer portion of the pulley" so you don't get into the bonded section.
  17. On a lathe I cut down the backside of the outer portion of the pulley equivalent to the thickness of trigger wheel. I then secured to the outer pulley by drilling/taping 3-4 holes and using locktite. I searched for pics of my old setup, but couldn't find any. Below is an example, but not mine.
  18. If the trigger wheel is larger in diameter vs the pulley you can machine the backside of the pulley to attach the trigger wheel. This is how I did it several times in the past with no issue.
  19. used L4N71B on a for drag racing and went ~129mph in the 1/4. Tranny held find, but due to excessive pressure it pushed out the front seal so definitely needs some additional case breathing. Biggest issue was getting someone to build a good converter and options were few and far between. Here is a link to the valve body mods. http://www.eng.famu.fsu.edu/~jthagard/4n71b/
  20. I also have an O5L head that I plan to use for my son's build so thanks for posting the pics. If you can provide some wall measurements for the intake & exhaust ports that would be great. I was the one who posted P90 cross section pics and the link is below. http://www.eng.famu.fsu.edu/~jthagard/3liter/pics/P90/
  21. The car actually made more torque, probably over 550ft-lbs @ wheels. The dyno graph below was running 28psi balls rich with no nitrous. At the track I would run ~20psi and spray 125shot. I ran it like this for many years with no issues, but you need to make sure the car is not detonating or it could be disastrous.
  22. I ran race prepped (peen & polish) 240Z rods making over 500ft-lbs@wheels and trapping 134mph in the quarter. Stock prepped rods are suitable for your goals.
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