another BT build, built block, possibly compound??

[soapisclean]

hi everyone, let me give a little background first, ive been a fan of the mazdaspeed vehicles as long as i could remember, and when i got old enough that the insurance wouldnt rape me i was able to pick up a speed6, this was about a year and a half ago. so after browsing the forums for all that time i have the basic bolt on mods, AP, HPFP internals, CPE top mount, BS delete, eBay catless downpipe, cobb tip, mazdaspeed intake, sure motor mounts all around (PMM, TMM, RMM, and rear diff front and back), and bunch of other little things, like an aeroforce, boost, oil pressure, oil temp gauges, short throw shifter etc. now to the juicy bit...

when i was doing my balance shaft delete i noticed a good amount of wear on the cylinder walls, this plus i was closing in on 100k miles prompted me to go for a rebuild. so i purchased everything needed for a solid rebuild.

CP 9.5:1 pistons .020 over
eagle rods
fidanza flywheel
act sprung 6 puck clutch disc
oem pressure plate (might swap this to something heavier)
new oil pump
new water pump
new vvt actuator
new thermostat
oem master gasket set, plus the rear main seal
arp crank bolt
arp flywheel bolt
arp head and main studs
new timing components (chain, guides and tensioner)
injectors and everything required to run extra injectors on each intake runner. still cant figure out if want to use megasquirt or that driver that comes with 6th port.
and a spare long block off a local
had the pistons and bearings coated with the dry film stuff and ceramic on the piston tops

after ripping apart the spare block and having it matched to the pistons and line honed i got to work on assembling the short block, head porting to come as well.

now to my problem, i cant figure out what turbo i want to run. im shooting for 500 or so hp. this isnt my daily, takes about 50% of the driving split with my dsm; so im not to greatly concerned with the drivability issues that might arise from a car like this. anyway, my plan at first was to run compound, use a evo 8 stock turbo to a hx 52 or 55. i did some crude measurements (best i could without having the turbos on hand) and found they should fit well if i mount the large turbo kind of where the battery sits. this set up though becomes super expensive, and pain to tune, and in general a pain in the ass. however it gives you a fast spool off the little turbo, and lots of top end off the big turbo. plus two turbos spooling sounds so bad ass. is there a single turbo option that would give me everything I am looking for? ive looked at teh garret turbos and while theyll get me to my power goals, they also come with the downside of bad spool characteristics. if anyone has any input on this i would appreciate it. ill post pictures in the next few days.

[Matrix311]

I vote BW EFR 7168, fast spool, integrated wastegate and integrated bpv and will meet your power goals.

[Lex]

For comfortable 500s you need additional 6th port fueling. For the turbo look at a gtx35, EFR mentioned above or a precision. It should flow at least 55 lbs but closer and a bit above 60 lbs is better due to losses at that power level.

[speed3sailor]

You should buy papasmurfs gt35 if it's not already sold. He is selling it for a great price


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[SpeedRebirth]

You might want to change the arp head studs for OEM or H11, preferably H11. Doing it right the first time will give you peace of mind

[soapisclean]

Originally Posted by SpeedRebirth You might want to change the arp head studs for OEM or H11, preferably H11. Doing it right the first time will give you peace of mind

yeah, ive considered this too, i bought them before i read more into head studs for our application. coming from dsm's it was a give in to use them. maybe ill get the block drilled and taped for 11mm studs anyway. wonder how much that will cost, the only machine shop close to my house is crazy overpriced unfortunately.

also i looked into those BW EFR turbos, pretty crazy set up, never saw a turbo that has a built in BPV. however that single turbo would cost more than my compound set up, and probably not have the same benefits. also im just looking for an excuse to buy a tubing bender to go along with my tig welder for the manifold.

[Easter Bunny]

Compound turbos is too complicated for only 500 hp.

[Roddiy]

Originally Posted by Easter Bunny Compound turbos is too complicated for only 500 hp.

This.


For 500hp you can just use a PTE 6262, you might even get away with a PTE 5857 if your setup flows correctly. Spool shouldn't be too laggy on the latter either.