My dyno woes
 

They continue. Fuck this shit in general. First there was this thread:

https://www.miataturbo.net/dynos-tim...-10-psi-67268/

And this dyno chart:

https://www.miataturbo.net/attachmen...ine=1342656433

Clearly showing some exhaust restriction and tuning issues. Artech's full 3" exhaust was installed and holy shit what a difference. This dyno followed:

https://www.miataturbo.net/dynos-tim...e6/#post981892

https://www.miataturbo.net/attachmen...ine=1361513000

I was over joyed, however I seemed to have some slow times at the track (I'm the left lane):

https://www.miataturbo.net/dynos-tim...-4-mile-74258/

https://www.miataturbo.net/attachmen...ine=1375595253

I blamed my neo gens, open diff, and noobness (my ten runs were my first and only ten drag runs ever), however for nearly 200hp, everyone was saying things weren't adding up.

Which made sense, when I went to ANOTHER dyno (#3) and this happened:

http://i414.photobucket.com/albums/p...psadd6c786.jpg

Went from 168 to 184. A huge improvement, especially in the midrange, it certainly helped that the dyno operator actually knew what he was doing and gave me some very helpful pointers. It was also an hour of dyno time, rather than 3 free tunes. My dyno cost between the three visits adds up to $25, and roughly 10-12 pulls.

I did find out that in a huge NW dyno challenge, the 193hp dyno was easily 10% HIGHER than all the other dynos in the area, which should of knocked me down to roughly 173hp. Not sure where the other 5hp was lost from my initial run, but theoretically if I go back to that 193hp dyno, it'll read somewhere around 212.

The very experienced and helpful operator/tuner says SR20s (the car, with my same turbo) run about 225 at my boost levels, so given the fact that I have a shitty stock head and .4 liters less, I'm right on target.

Feel free to criticize, I'm very happy with the results, and yes, I hope to get back to the drags sometime soon.

What was the exact changes between dyno 1 and 2? I understand dyno 2 was full 3" ARTech goodness- was dyno 1 with stock midpipe and exhaust or some other crappy setup?

Dyno #1 was Abe's log manifold, 3" DP, a 2.5" cat, then 2.5" crushed crush bent pipe through a muffler. It was seriously ugly and restrictive.

Dyno #2 was the same, except a 3" test pipe, and 3" mandrel bends through a 3" magnaflow, and very small changes in tune to compensate.

Dyno #3 was the same as above, except with a rebuilt head (seals, seats, and surface, no porting), and a few track days and drag runs. It did feel SLIGHTLY down on power between #2&3, I'd be interested to see compression numbers from my engine.

Sub'd for discussion.

Curly, what kind of shape is your longblock in?

It's been rebuilt to stock spec a number of times. Well, twice. One at 90,000, and then just rings at about 115, currently at 126,000.

Rings at 115 were just cause I had the engine out for a clutch, pan off for a oil drain bung, and head off for a surface.

And these are all estimations, I could be off +/- 10,000 miles, I'm horrible at keeping track of that sort of data. I do know it's currently at 126k though.

Tiny turbo is tiny. I have one too, and it's... small. Honestly these things are okay for 200whp, but don't expect much more even wringing the shit out of it.

Time for bigger turbo and more boost.

I think I see the problem. Only 126K on a '93? You obviously need to drive it more. ;)

I do, it's an absolute DD blast right now, with an ebay amp and silky smooth bilsteins. I need just slightly less humidity and legal registration and I'd be driving it a lot more.

Fireinc, I realize it's tiny, I have always hoped for 200hp and no more, due to my 5spd and stock rods. I was just hoping I'd get closer. I need to grow some balls and go to 14-15 psi I think.

949's clutch and another used 5spd is my next project though, it's whining in every gear except 4th, and even at idle with just the input shaft spinning, it whines. My car sounds like it has a supercharger.

Ahh yess, I feel you. On my 99 motor virtual dyno said I was making 190whp @9psi or so. I really doubt it will make much over 215-220whp even tapped out though. This is why I'm going to be looking into something bigger soon.

dyno #2 should read 12% lower than dyno #3. sounds like they add in tons of correction to make you feel good about yourself.

Punch that bitch to 14psi.

Is it possible your timing belt is off a notch? Savington drove around with an engine like that for a while :)

Im currently building a very similar setup, the car has a 2.25" mandrel bent straight through rear section but will have a 3" downpipe and cat.

Same turbo, same manifold design, same 1.6L everything, it will be interesting to see the results.

Dann

MOAR BOOST is always the correct answer.

I know, after seeing numbers well under the safety margin of 200, I wanted to, but decided since we didn't see a huge gain going from 11 to 12, to leave it. For the road racing I do, it's plenty and my free dyno time gave me an incredible amount of knowledge, 20hp, and nearly 20 ft/lbs.

I know it requires a decent additional investment, but I feel like a 2560 would blow your mind. That turbo really is damn near perfect on a stock motor IMO.

I agree wholeheartedly. Bolts right on, 150 bucks and a tune.

Dann

yeah i don't really like the SR20 t25 on a 1.6L due to the .86 A/R turbine housing.

however, Results seem on par for the boost level.

That's all I hoped for. I don't remember hearing that my 193 was spectacular, so I was worried 184 would mean somethings wrong.

184hp on a dynojet at 10psi with that turbo aint shabby. I've done 187rwhp dynojet pulls at 12psi with a poor tune on a bigger turbo.