Here's one for you guys to laugh at. Did this on Sunday on a Mustang. This is a Greddy with no intercooler and the Greddy downpipe. Boosting about 9-10psi with water injection. Engine has 200K miles with bolts that were last torqued in Hiroshima in 1989. Definitely have some low-hanging fruit to add power, but I need to swap my diff first. Note that the RPM scaling on the dyno plot is a little off. I let off at 6,850 according to the MS.

It is a fun driver though.

 

Did some virtual dyno pulls last night and got the following results:


The changes between this and the earlier dyno are:
1. I've got a new crate engine installed. Has about 10K miles.
2. Added COPs and increased spark plug gap.
3. Timing in boost has been backed off. With the new engine (better compression) I was picking up some det above 6K on the original timing map.
4. Running a bit less rich in boost.
5. 3rd gear instead of 4th gear.

Virtual Dyno seems to give a really good match to the real thing. Peak torque is nearly the same as before (considering the gear difference, probably means the crate engine is making about 10ft-lbs more than the tired engine it replaced), but the engine is maintaining the torque much later into the rev range, resulting in quite a bit more power.

Also, to soothe my ego, I can plot it with a DynoJet simulation:

 

Your last name is Price??? thats MY last name! you cant have it! lol
But, for real, i have an uncle named Rick Price. lol

Have you changed anything on the car between these charts?

 

Break out a healthy stack of hundred dollar bills, report back to us in six months.

 

I've been a Price longer than you have.

No other changes to the car beyond what was listed.

Done!

Recently installed a Torsen to facilitate exactly this. That would be 6 bills.

My next move is a BEGI DP + Enthuza Exhaust and Test Pipe. Got these used for 3 bills. I actually did the pulls last night preparing for the exhaust change. I wanted to quantify the effect.

 

That is a good move, interested to see the results.

 

Actually, there was one other change between the dynos -- I added COPs and increased the spark plug gap. That may explain part of the torque increase at higher RPMs.

 

I think I'll try this software out when I get home. I just installed my kit and am making a whopping 4psi. Should be fun.

 

Got my new exhaust mounted. Specs:

Old:
1. Stock Greddy DP.
2. OEM header pipe from triangle flange to cat. (I am NOT going to miss that damn triangle).
3. High-flow metallic cat.
4. Cobalt exhaust system (62mm + resonator + chambered muffler). 62mm is about 2.4".

New:
1. BEGI Greddy replacement DP with SG pipe for the wastegate and 2.5" termination. (thank you Kotomile and FRTFun -- I'm the 3rd owner)
2. 2.5" test pipe.
3. Enthuza 2.5" turbo racer exhaust with Borla straight-through muffler.

And here is the comparison (Mustang simulation):


Old exhaust is the blue line. New exhaust is the red line. The days (9/9 and 9/26) were remarkably similar (both 92°F, baro was 29.96 on the 9th vs. 29.83 today). The only real difference is that I had a lot less heat soak on the 9th (peak MAT of 180°F vs. 213°F today). I messed with the SAE correction values to try to compensate for that -- have no idea whether what I did is valid though.

The new exhaust clearly helped spool. You can see the boost rise much earlier and the torque fatten at lower RPMs. Surprisingly though, it had very little effect at higher RPMs. Not what I expected at all. Pretty disappointed. Perhaps I'm running low enough boost that the old exhaust wasn't actually that restrictive for power?

 

how much timing your running in boost?

 

lol mine made 150 at 5 psi in 110F ambient temp, no IC, at 15 degrees timing (would knock because of the temp)

 

If a stock one makes like.. 85 and you increase intake pressure from 15 to 20psi, how do you hit 150?

Dann

 

wut?

 

Stock pressure at the inlet valve is 15psi (1 Bar) he has added a further 5 increasing pressure by 33% and improved VE by 90% . I simply dont understand how this can be.

Dann

 

because his 10AE makes about ~110hp at atmospheric and if he adds about 10hp per psi it makes perfect sense.

meanwhile in AUS, you are the highest claimed ft-lb per MAP of any miata in the world and you still don't understand why your results are controversial.

 

This is the (very conservative) spark map that was used for both sets of pulls:



Please keep in mind that what I'm focusing on is comparison values to evaluate the change. The absolute number are, well, meh. If I wanted "impressive" numbers, I would have thrown up the "DynoJet" emulation. LOL.

I saw the exhaust change comparisons done by Curly and Brain and expected similar results. In both those cases, there were pretty good gains at high RPMs due to the improved VE. Just not seeing it here for some reason.

I'm also planning to do another set of pulls once it warms up this afternoon. I got heat soaked due to stop and go traffic + using AC just before the pulls. I should be able to get a better comparison without using the SAE correction "guesstimating."

 

It was hilarious how mad you guys got.

Look, 110rwhp isnt what any 10AE makes on a dyno in australia, american dynos do seem to read a little higher.

If they read 110rwhp for a STOCK car than 145whp is what you would expect out of 5psi and then the exhaust and tune gets the rest, fair enough.

Dann