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240Z Turbo

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    Charlotte, North Carolina

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  1. 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 If you look at my CAT placement below it is considerably further back vs what you proposed and it seems to make a very noticeable difference in terms of sound and soot. I had to place it so far back so I could integrate a 4" dump valve. So now I can cruise around with the CAT and when I want all out power I can open the dump.
  2. 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.
  3. 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.
  4. 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 MAF setup and I needed the larger piping on the post IC due to flow limitations. You don't want to go too big or you lose velocity in the pipe, which decreases throttle response and turbo response. If we assume you will want to support 400hp@flywheel then you need to flow ~600cfm. If you look at Corky Bell's book Maximum Boost, he says to keep charge velocity below 450fps to avoid excessive drag. A 2.5" pipe flowing 600cfm has a charge velocity of 293fps so well below the limit. A 2.25" pipe has a charge velocity of 362fps and 2.00" pipe has a charge velocity of 458fps. I would personally probably run 2.25" or 2.50" the whole way or you can mix and match based on the above density theory. Beyond 2.50" serves no purpose.
  5. 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 my turbocharged 240Z that was running in the low 20's psi range it was a surprise that I was able to run so much boost on the EVO. 33-34psi is very common for the EVO on pump 93 and I have been running it this way for 4-5 years on the same engine. Keep in mind that I run -1deg of timing at peak torque and ramp it up to +8deg at redline so significantly lower timing than the L-series and my GTR. If you need a larger Tial housing just PM me and I will help you.
  6. 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 don't know how much more power it will make. My GTR put down ~705hp@wheels on 93 pump and ran 10.2@138 on the same pump gas tune, but running race gas. The GTR doesn't feel like its got 700hp@wheels because its a big/heavy car so it is deceptively smooth at that power level. Higher compression is nice and my EVO is 10:1 and most built GTR engines are in the 9:1 to 10:1 range even running pump 93. However, the fact that you run low compression is not necessarily bad and just look at TimZ and his 7.5:1 monster making in the 700hp@wheels range on E85. I think that was his old compression and suspect he still runs low compression, but he might chime in and correct me on that. If you want to understand the turbine restriction you can put a port on your exhaust manifold to measure Exhaust Gas Back Pressure before the turbo. Off the top of my head you want to be in the 1.5x boost range and if you measure post turbo on the downpipe you ideally want to be in the 1psi range, but slightly higher is likely also fine. Maybe you can post a log shot of your AFR, boost, and timing curves as a function of RPM. Also, the dyno results you posted, are they a direct before/after of old turbo vs new turbo with no other changes or did you make changes?
  7. 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 37psi tapering to 33psi on 110L and 1.01ar Vband TS. Since I log turbo speed the turbo was riding the choke line on the 573hp@wheel dyno pass so I gave it everything it had. The GTX3576r has the same turbine wheel as the old school 35r, but new billet compressor wheel so it actually flows more than the old 35r. This turbo flows ~64lbs/min so not gonna support 600hp@wheels on a accurate dyno unless your drivetrain loss is ~40hp. The fact that your pushing it past 22psi and not seeing a difference suggests you have a restriction in your system. Also, the .63a/r is small for a 2.8L so likely part of the problem and in general I don't like running open scroll because you sacrifice too much spool and gain little on the topend, but I do understand it is not an easy option to run a TS on the L28 due to lack of available manifolds. I saw ~400rpm loss in spool when going from 0.63 to 0.82 on the EVO, but gained ~35hp on the topend when I used to run an open scroll setup with the GTX3076r. Also, on my initial TS setup I lost no spool and gained ~50whp when swapping from the GTX3076r to the GTX3576r so turbine size does matter.
  8. 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.
  9. As previously stated, you "cut down the backside of the outer portion of the pulley" so you don't get into the bonded section.
  10. 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.
  11. 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.
  12. 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/
  13. 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/
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