Blackbird

Order has been restored, started troubleshooting at 5am, car is now running.
Sometimes all you need is a good night sleep and a clear head.

M.Adamovits

So, dyno day today?

Blackbird

Appt already rescheduled, might as well use the time to keep plugging at the mile long to-do list that we still have...

oregonmon

I have, this was an inside joke between Aidan and I.

HarryB

So, what was the issue?

Blackbird

Missing ground wire that got cut during the harness diet.

Blackbird

So in case anyone missed it on the other thread, Creampuff ended up making 274.6 / 227.1 on pump at the Church dyno.
At full song it made 14 psi of boost, red line set to 7K.

What kind of boost do others see from a 75mm pulley on a BP4W with supporting mods (ST, H, E)?

Roda

Great result!

Motor details? Stock BP4W long block?

k24madness

iTrader: (6)

I need to go back and see what I am missing. I have mine geared for max RPM at 8k redline. When run to 7,700RPM's I am only getting 9psi of boost. The head/cams flow great (BP4W) so that's part of the reason for low boost. I made 297whp on E85 so maybe there is more left in it. Time to look closer at IC losses and possible boost leaks.

18psi

iTrader: (76)

aka moon dyno.
but it doesn't matter because I'm sure that thing will be seriously fast

Blackbird

Roda - unopened BP4W.

K24M - are you running a C30-74? you're probably losing boost somewhere.
Show me the air flow path.

18psi - Those who have been to the dyno many more times than I have as well as to other dynos say it reads 10% high.
If you took 10% off the numbers are still great at ~248/205.
And yeah that car will be fast, between having more than double the power, huge weight loss, a bunch more rubber under the fenders (245 A7 as opposed to 205 RR) and the most radical aero that has ever been done on a Miata, the potential is there.
Only trouble right now is suspension tuning, I had to take a shot in the dark because so much of what's going on with the aero has never been done on a Miata before... hopefully I got it in the ballpark.

dcamp2

iTrader: (4)

I think I was up around 10psi with a 75mm pulley... At altitude though (5000ft) not sure if this would change at sea level or not?

Creampuff will be seriously fast... good luck!

k24madness

iTrader: (6)

Yeah C30-74, Redline at 7,700 is 116k blower speed.
Air path is REALLY straight but IC is suspect for losses. Lots of welded piping so the pin holes could be adding up to serious losses. I need to rig a pressure tester. When I did the same on my old Audi I was shocked at what I discovered.


That seems a bit more inline with what I expected. I got 230whp out of the C30-74 on E85 with 88mm pulley and stock 130mm crank pulley.

Again congrats on what will be a solid setup.