I need to look into a brake bias adjuster, probably something from Wilwood or Tilton. There's a restrictor in the BMC as standard that I'm trying to find more about as well. Blind confidence combined with stubbornness has gotten me this far. Sure did Robbo. Thanks again.
Bit more news, as well as some actual progress photos from the car. sorry about pic quality! New order came in from J-land including my new Bride seat rails (Recaro rails went with the OEM Recaros), new head gasket and some more old school jap bits. a girl's gotta know how to accessorise been meaning to replace my fake rays wheel nuts for a while now, leading to the RUCA's being the only non-name brand name part left to be rid of a fresh pair of head gaskets came in straight from tomei direct, 89mm x 1.2mm. Thinnest gasket they offer, and also the smallest bore - surprising being 2mm oversize. any and every part for the engine itself has now been purchased, just some assembly left! progress update on the bay... now that I actually have my welder back from repair I have started on the list of shit I prepped part 1 closing off the front rad support... the hood latch is staying and I wanted to mirror its cut out while closing off the surrounding area. like a permanent, welded in air guide. what better way to do that then with the exact same oem shape... the doner car's front end was bent up, amazingly only the centre of the rad support coming out unscathed all welded up... getting better with the mig, but a still room for improvement. stage one is complete with two more coming. going to have to modify the latch itself too so it clears. more content on its way, next section is all welded up and just needs to be ground down at this stage. -A
Clever thinking with the radiator support, i never thought of mirroring in a duplicate piece. Doing the same mod myself but cutting from sheet metal to suit. -Tis a bit too tedious for the tin snips cutting and shaping right now. Great stuff Anti, Z Pro custom!!
progress on the bay is coming along. as the fabrication side of things predominantly takes over what I'm doing on the zed it's a much more time consuming and frustrating process making headway. this is purely because until I get more experience I am working beyond my level of skill, meaning I do most things 3-4 times over before getting them right. frustrating but I guess I'll get there. continuing from the last post, the centre rad support extension was bent up. It covers up to just under the nose panel, so there're not gaps visible once the car is assembled. simple bends and simple weld makes for a happy anti before the piece permanently attached I fully welded the underside so the bend could be smoothed down later on. plenty of "measure twice, cut once" went into final positioning of the panel aaaand fully ground down ready for a touch of lead, filler and primer. in the interest of minimalism, I also made my crossmember and upper control arm mounting bolts disappear; countersinking them and welding them into the chassis. this started with knocking off the old mounting brackets for the bolts once removed from the brackets, the oem upper control arm bracket bolt heads are perfect for welding to the strut tower. the frame rails are so thick that opening up the top deep enough for the head of the bolt doesn't cut all the way through. bam, and the bolt is gone. the bolt heads and surrounding metalwork are very thick so it's as strong and ever, and with the suspension loaded up there is no force on any of these bolts anyway. the next step of the bay is just about finished up so i'll post about that one soon. lastly, another little sneak peak tidbit for the motor -A
some more news... been working slowly through the bay fab stuff, two items in particular have been taking up my time that I'll post up about soon. couldn't miss an opportunity and bought a custom semi equal length big single manifold set. something something constant desire to be different these were designed and fabricated here in aus by Chris / JDM Automotive for his own personal car. the turbo is low mounted in the same space as the passenger side turbo in a standard TT. the exhaust crosses the bay around the back, over the gearbox. a custom engine mount was also included in order to make space for a sizeable turbo despite the excellent tigs it had no rust protection whatsoever. as you all know I can't leave well enough alone. in preparation for the manifolds arriving I picked up a mock-up motor, which will allow me to get straight to modifying the set up before my donk was done (still at the builders for the time being). as per the standard SMIC's sitting in the front end, I'll be making up a single entry, twin exit vertical core FMIC to suit the new set up. much to my regret this means my much loved custom intercooler has to go those that know my goals for the car will know that the "big **** off single" conversion doesn't exactly fit my response > power ethos. if you're wondering then what I'm doing with them in the first place... I've begun mocking up an even bigger single in the battery tray and here is the plan. -A
THIS IS BEST! Cars that run an aftermarket compound turbo setup feel amazing on the street. Any idea on sizing or is that in the "futture problems" basket?
Compound ...What are plumbing disaster on a zed I know you want to be different ,but what are you expecting from this ?. You won't get better performance from a good normal twin set up. .
what am I expecting? I don't know... build something silly and have fun doing it I already started investing in a good twin set up, I was going to import a pair of borg warner 6258s (they put your disco potatoes to shame rob!) and get the same maker of my single manifolds to work his magic on a new pair of equal length tubular units, a la this. this new set up should be similar down low without tapering off in the top end. we'll see. and no, the turbo choice is currently in the "too hard" basket while I focus on other tasks at hand with the car namely, as niall pointed out... turning it from a wreck on stands actually into a car again.
Well that explains why you were chasing a big waste gate haha! Got the plumbing routing sorted out? Gonna be a ummm "challenge" haha!
Pretty much. The current wastegate plumbing will have to open up and route up to the battery tray, merging with the small turbo dump pipe. Outlet from the big turbo in the battery tray will have to go around the strut tower and loop over the top of the passenger manifold to the inlet of the small one. The outlet of the small turbo will route up and exit the bay through the stock passenger intake accordion tract to a single intake, twin exit vertical core FMIC. Big turbo inlet will see a 5" hole saw to the far side of the battery tray with whatever filter I can fit inside the guard, likely a HKS mushroom (and to think I already welded the fender braces on, urgh). The OEM pass through to the guard is already welded up which will make it simple (old pic here where you can see where I mean, below the front of the brace, still with OEM plastic cover clipped on). it gets a bit sketchy when it comes to the big turbo dump pipe... it looks like I might have to scallop the firewall for clearance. big turbo placement will be sort of similar to this, mirrored for RHD obviously. that's a single GT42 build, with lots of space for a bid dump without the extra plumbing I'll have to pack in.
Remember, pressure ratios multiply and the pressure ratios the small turbo creates at a certain boost pressure are different based on what boost the big turbo runs. Its not as simple as X turbo spools up quick and Y turbo makes a billion hp. Tell me your max RPM, what headwork it will have and i will give you some quick feedback on what would work decently. The compounds i have chosen for my car won't be compatible with your engine, you'd need a bit bigger.
Okie dokie, lets get down to business. Here's what i would choose if i was in your situation. Boost pressure i used for this was 3:1PR(29.4PSI gauge). Using a GT45R as a single at this PR would result in this, would make great power up top but down low we see its to the left of the surge line. This turbo would probably be on boost well into the 5000-5500RPM range. When you run compound turbo's, the pressure ratio multiplies between the stages, so a TOTAL 3:1PR split equally between the two compressors becomes 1.73:1PR on each turbo. Which ends up as something like this, the system is still flowing the same amount of air, but because the pressure ratio is split equally, it is only running 1.73:1PR(10.7PSI) on this large compressor. We see this causes the turbo to drop onto a lower efficiency part of the map, this would cause hotter charge temps and would lower theoretical maximum power. However we see this turbo IS NEVER SURGING, this turbo would spool up very close to the small turbo it is attached to, provided the small turbo can flow enough. Here's the small turbo, a very good match for the 3L engine on its own so it works VERY well in this compound setup. A few things to note, the large turbo must be mapped first and then work backwards from there to be able to choose a suitable small turbo. BOTH turbos have to end up on the compressor map, if you end up off the map on either you will not make the power you desire and the system won't work very well. To map the small turbo you take total mass flow and divide it by the large turbos pressure ratio. GT3582R at 1.73:1PR, now here's the funny part, this turbo is not seeing atmospheric pressure(14.7PSI) it is seeing atmospheric pressure PLUS the added boost from the large compressor(10.7PSI). So for the small turbo to supply a 1.73:1PR it must produce 18.7PSI of boost. Quick stuff: For the turbos to be in series compound the boost reference from the large turbos wastegate goes to the top port of the small turbos wastegate. So even though you end up with PR's multiplying, you end up with boost pressures adding. Its not all good though, as pressure is multiplied on the compressor side, it does so on the exhaust side. The backpressure also gets compounded, this gets worse as you run the turbos closer to the end of the compressor maps and you must be mindful of what turbine housings you choose, but from what i've been told as big as possible on the large turbo would be best. You don't HAVE to split the pressure ratios equally but raising the PR on one to help efficiency lowers the other. External gates only! Internals won't work simply put. There are ways to shift the pressure ratios around, such as bypassing the small turbo completely for the big turbo to take over completely up top but i will leave that for another time. PS: Yes most of you know mine is going compound aswell, i get my knowledge from people who actually run the setups. Kevin Jewer ran 8's at 155+ with his compounds and his 2L DSM spooled up a Borgwarner S475 1.32A/R at 4500RPM(45PSI total boost). Another thing to remember, a compound setup isn't about MAX power, its about a wide powerband. I know probably all of you would think this is stupid, but not everyone wants to run the same setup as everyone else or have to pull the engine in case of a turbo failure.
Just a video for reference, Marc at boostlogic's Z31 compound turbo 2JZ(Stock DE 10.5:1 Motor). GT35R 1.06 + quick spool valve and a GT45R 1.44A/R. 24PSI by 3500RPM and 700rwhp up top. [yt]A5IqGBbsHio[/yt] [yt]ZZgf_JG4lbA[/yt] Traps 144MPH from what i remember.
