My NA miata dyno
 

here is my latest. Not stellar for you turbo guys but I am happy.

I am rounding up and calling it 149WHP! I need to get the drf file so I can show AFR and RPM but for now all I got is this pic. But AFR is flat 13 across the board. I never did get VVT working, and it shows. Supposedly the adaptronics controls it. but between myself and the vendor, our collecteve engineering degrees havn't figureed out how to make it happen in an NA car.

But I am very happy with the HP number considering I am running a full exhaust. I plan to convert to a CSP style exhaust real soon that will just be a couple resonator mufflers and a turn down and I think I will be over the 150 mark easy.

Oh and here is a biggie, that beats IRTB’s! I made 143 with them. So yeah, the BEGI swap was worth the effort. I was just hoping to match the IRTB’s I used to have and gain TQ. the 6 extra HP is just gravy. And it pulls hard when revving out. Also I think it may actually be 150+ when driving, considering that the dyno does not simulate wind that my intake setup takes advantage of. It sounds awesome too, even all the Honda hotrod boys that hang around at the shop were impressed with the acoustics.

Now to get the VVT mid range torque working and it will really be cooking.



I have a 96 miata with:
2001 Engine and 6-spd transmission
Adaptronics ECU (supposedly with VVT control, however couldn't get it working)
Jackson Racing Cold air intake, with some extra insulation
BEGI Custom lightweight AL long runner intake manifold (stock TB on it)
BEGI High Flow Fuel Distibution Block and Lines
Racing Beat 4-1 Header with DEI heat wrap
Racing Beat test pipe and full Racing Beat exhaust
Fidanza 1.6 Flywheel
Spec stage 3 light-weight clutch
OBX Aluminum Underdrive Pulley with PS/AC pulley machined off
Torsen LSD with 4.1 final drive gear

Ever come up to Jackson?

My in-laws live in brandon. so yeah. but I don't usually have the miata.

I will be going to columbus next weekend (may 1&2) to run on a 1500' concrete airstrip that grips like velcro.

There are two threads involving VVT tuning in the forum, I suggest you subscribe to both. IIRC Savington is at ~300whp at ~14psi O_O with the use of VVT

Nice numbers. NEEDS MORE SNAIL :D

Dynojet? 4th gear?

yup DJ, in 5th (of 6)

Are you still using the stock harmonic balancer?

no, using an aluminum pulley.

FYI the oil pump failures are a turbo thing. with NA power it hasn't been an issue.

No, its a harmonic thing. There have been several NA failures IIRC. Give it time.

Also, revving the motor past the stock redline speeds up the process.

this is win. I'd be happy with 150rwhp dynojet N/A in a NA.

Ah, so were talking probably 130-135 on a mustang dyno

which makes a lot more sense

MD for real hp
dynojet for bragging rights

saw da same. so long as we know its a dynojet we know how it compares to most others.

That surprises me about beating your irtb set up. What size choke did you have in them? It took some experimenting to get mine right.

IMO you should lose that aluminum pulley ASAP. i doubt you'll lose much power...

+1

I ditched mine, and was able to bring up the total timing. With the aluminum pulley, I could only go to about 32 to 34 degrees total. Any more, and performance dropped off.

I asked about the harmonic balancer because our little engines have a lot of trouble with harmonics and catastrophic failure. The harmonics have nothing to do with forced induction and everything to do with reciprocal motion, rotational motion, and combustion force pulse frequencies. The crankshaft does not spin at 5000rpm just because the tach reads 5000rpm. At any given point in the rotation of a crankshaft it is either slowing down or speeding up. Add to this the fact that three rods might be resisting rotational motion while a fourth is trying to force it to rotate it faster. Since all of the rods aren't bolted to the same point on the crank, these rods are trying to twist the crankshaft in different directions at different ends, or even in the middle against both ends. There is also a tendency for the crankshaft to want to bend in the middle like a jump rope when force is applied to one of the middle two crankshaft throws. Then there are the uneven amounts of rotational resistance applied to the end of the crankshaft by the camshafts as they have both rotational inertia and odd intervals of resistant force. Then you have the oil pump gear, which is somewhat delicate, being subjected to all of these thrumming, chattering forces.

The harmonic damper was designed by people in white coats with calculators in their front pockets to stop some of the nasty things their very large computers said might happen if they didn't place it there. Trust me, they would rather not have spent the money on it if they thought they could get away with it.

The people racing in Spec Miata would not run a harmonic balancer/damper if there was any benefit to be attained. I believe they even run a better one than stock.

I sincerely hope that no failures befall your engine. That is the purpose of my interest in the matter. It is not simply to b able to tell someone they are doing something wrong.

Good luck.

^this.

Some engines can run lightweight crank pulleys at lower power levels. But the BP is not one of those engines. These things have lots of issues with vibration and harmonics.
Just look how these cars break turbo manifolds, Ive never seen anything like it. Lots of cars can run forever with manifolds made out of tubing, yet we consider sch 40 pipe to be a minimum.

I experimented with different lenth bellmouths and size chokes. I thik the best that I settled with was a 3/4" bellmouth and a 38mm choke.

The conclusion I draw is that IRTB's work great if you have added cams, CR, and high RPM. if you could see the curve the HP peak is at 7500 where I had the rev lmit, and it looks like the curve was still going up.

in the class I play in CSP, the engines have to remain stock. so the manifold does a good job working with a stock motor. it peaks at 7000 and starts to fall off.

Also note, the peaks are very close. I looked at apples to apples and compared (SAE correction , and RPM based) and they are only 2.7HP difference. if I could keep revving to 8500+ with the IRTB's then they might be the winner.

I did like the IRTB's but they are peaky. I decided to go with the BEGI manifold in search of more mid range TQ. and I am very pleased with the results.

Stock cam and 7500 was at peak horsepower and still climbing:eek5:.

What have you done with cam and ignition timing? I heard if you advance the intake cam it will keep the engine from reving too high. I have not tried it yet, so there is a disclaimer there.