Bronson M

iTrader: (1)

Yeah it's gonna be interesting, have an HPDE the following weekend so a little more top end pull will keep those pesky vetts close enough in the straits to bug em in the turns. I can keep the revs between 5000-7400 which should be high enough to make the HP without the torque

andyfloyd

Im pretty impressed your doing all this on the stock bottom end. Are you going to try to taper boost to redline to maintain tq? Like say youve got 10psi @ 4k but then past 5000rpm feed in more boost to end up at like 16-17 by redline?

Bronson M

iTrader: (1)

That's exactly what I plan to do, I start at 10psi at 4k now and ramp to 14psi by 5.5k.

andyfloyd

Right on brother, good luck this weekend.

B Mike

92 octane? Stock fpr?

Bronson M

iTrader: (1)

For me, yes 93 octane, 650cc injectors, walbro 190 on stoc NB FPR. I'm seeing right at 80% duty cycle with 62psi and 11.4ish AFR's

andyfloyd

93 octane, stock fpr. I don't have a fuel pressure gauge but with 550s my duty cycle is about 84% at redline. Pretty much maxed out the injectors they might have a little left in them. I'm pretty much at the limit of my setup, injectors/turbo. But I'm happy with it.

andyfloyd

Your duty cycle suggests you are in the 300whp range. I'm actually surprised my duty isn't higher honestly. Maybe the Hydra and ms3 read duty cycle differently? I'm really curious what kinda power your making. I read your build thread, in one picture I saw your turbine wheel. It looked clipped and I swear it has one less blade than mine. Is it a straight 2560? Or do you have a gt28 turbine wheel?

Bronson M

iTrader: (1)

Yeah the wheel has seen some things, the small chip isn't too bad but it's there. It's not a 28 wheel as far as I know, just a journal bearing 2560. Duty cycle is duty cycle, so should be the same. I'm running pretty rich, that might explain the difference......or I'm just making way more than i think.

B Mike

The fuel pump might be helping.

andyfloyd

Your running a Wally 190, I'm on a 255 that could account for the difference. I'm sure my base pressure is over 60 since the stock fpr gets overpowered by a 255hp. I didn't realize you were on a journal bearing. Really it's the same turbo, probably isn't much difference in spool maybe just transient response.

andyfloyd

Yea the Wally 255hp is a little more pump than a 190.

Bronson M

iTrader: (1)

I data log my fuel pressure and actually had a 255, it does over power the NB regulator at low PW, would rock up to 70psi and caused all kinds of funky transient fueling issues. I would see about 58psi at redline with the 255 still, with the 190 I see 56-57 psi. I chalk this up to pressure drop through the lines since both pumps are over kill for this power level.

andyfloyd

Interesting. Before the 255hp I had a dw200 which is also a 255lph pump. If I have more fuel pressure at low PW then I've never known. I tuned my fuel map extensively over many months and I have excellent driveability. At idle though my car doesn't like to run any leaner than 13. If I go leaner by reducing PW the idle will hunt around and get wonky at times.

Bronson M

iTrader: (1)

Where I saw the problem was on AE, if I was at part throttle the fuel pressure would be at 62 psi and on a throttle stab the motor would want a certain amount of AE. If I was off the throttle in overrun the fuel pressure would be in the low 70's and a throttle stab would nearly drown the motor.

andyfloyd

Hmm, I can see why you wanted to go with the 190 instead. My car doesn't exhibit this behavior but you do run a slightly bigger injector than I do. I'm still on old school rc550s that came with the turbo stuff I bought years ago.

Bronson M

iTrader: (1)

For the others that are following along, my dyno day was a bust. I have some odd issue going on where the motor is surging and not making power. Replaced coils and plugs with no improvement, changing cam and crank sensors next and then fixing with an LS swap after that.........aren't race cars fun.

andyfloyd

It really sucks that it runs perfect for so long then hates life right when you want to Dyno it lol. I understand the LS swap thing, however I actually like the BP... This makes me tarded' obviously.

B Mike

I like this engine build. I just need rods-head-exhaust and should be close to your numbers. 300 seems to be the max before things get pricey.

andyfloyd

300whp is a good number in a Miata. Its pretty quick, but its generally not breaking a bunch of stuff.