DammitBeavis

I was using the lb/min calculator here: Ray Hall Turbocharging - Java turbocharger flow map calculator

RPM points were 3000-4000-5000-6000-7000
VE was 80% across the board
Compressor efficiency was whatever my map said it would be when i punched in the boost and got a flow calculation.
Bore was 3.307in
Stroke was 3.346in
Cyl 4
Air Temp 20C
Intercooler Efficiency 70%

Basically I put in the values initially shaped on a T3-60 map, then used the lb/min numbers to cross reference it to a GT2560 map and make some adjustments.

My aim was to get the torque up to ~200lb-ft as fast as possible and hold it there as long as possible without heat-soaking my old Flying Miata intercooler.

Mobius

iTrader: (2)

I put together this spreadsheet a while back to help me decide between the 2560 and 2860rs. Take a look and see if it helps.

Braineack

iTrader: (62)

This assumes 18psi to make 300rwhp. Will it take 18psi to make 300rwhp...I dunno. The math in the turbo tech 103 is pretty good.

this is why I'm found of the 2871:

Mobius

iTrader: (2)

RE: 18psi for 300hp, I built the spreadsheet from the tech103 article and Corky's book. I then scaled/fudge factored so that the numbers matched several real-world examples I'm aware of for 240hp at 12psi. 18psi for 300hp is what came out of that.

Braineack

iTrader: (62)

there are so many factors, it's really impossible and wrong to say 18psi = 300rwhp. Remember Paul has made both 270rwhp and 300rwhp at 14psi on his 2560 all thing but the intake manifold being equal.

DammitBeavis

Your calculators are more generous with airflow/psi than mine were. I was showing 22psi was necessary for 300WHP@7000.

According to your numbers I would still have some headroom left from ~4000 to ~6000 on the 2560 to bump up the torque even more.

patsmx5

iTrader: (16)

Braineack, what's the basis behind the red dots? Reference points to different RPMs? I might try to do a map like that for different boost and RPMS for my GT3271. Would be interesting for sure.

BradC

iTrader: (6)

https://www.miataturbo.net/forum/t23229/

They are plots to show where on the compressor map the flow would fall at any given pressure ratio.

Braineack

iTrader: (62)

Squirrel Performance - Turbo Calculator Version 4

Braineack

iTrader: (62)

see what Paul did to run 300rwhp @ 14psi and then 310rwhp @ 17psi, the turbo is completely spent.

patsmx5

iTrader: (16)

My turbo at 16 PSI



My turbo at 21 PSI:





My turbo at 24 PSI:





My turbo at 11 PSI, where I'm at now:

DammitBeavis

That's very encouraging.
According to Paul's sig he has better exhaust flow than I will which means I probably won't hit that kind of topend power. But it looks like he ran a flat amount of boost. I've got a ported/polished head with big backcut valves, so hopefully I can hold ~250lb/ft through the midrange with a strategically shaped boost curve.

What kind a fuel was that on?

y8s

iTrader: (8)

I like the 2871-2 for 300-350 hp...

Braineack

iTrader: (62)

93 octane, keep in mind his IM as well, that made all the difference in the world for his torque curve.

patsmx5

iTrader: (16)

No kidding. Where's all the badass intake manifolds that are supposed to be put into production this winter?....

And looks my turbo's pretty efficient for a 1.8L.

Braineack

iTrader: (62)

like this one?



I know of two other 1.6Ls that have IMs on the way.

thesnowboarder

iTrader: (15)

Brain, whats the deal with the front temp sensor broken off? How are you controlling the fan?

Savington

iTrader: (31)

Plug your IAT sensor in

Braineack

iTrader: (62)

I use MS to control the fans, that thermoswitch is now a simple plug to prevent coolant from sparying all over the place.

I use that spare AIT to plug the bung, I have yet to buy a real 3/8" plug for it. The AIT sensor is connected and installed out of the engine bay just after the IC.

y8s

iTrader: (8)

i might have a 3/8 plug in my basement. remind or come by tonight and we'll look.