Built High Comp N/A 1.8L Track car
 

Specs:
1.8 Block with 11.5:1 Supertech pistons and CAT rods,
8 lb Lightened Crank
99 Head w/ BP5A intake cam
EUDM "Square-top" Intake manifold
Racing Beat 4-1 Header
Simpson Dyno Spec miata exhaust
Hydra 2.17


This car is very fast with this motor and how light it is. It is going to really tear ass at the track. There is still a lot of tuning to do, but this gets us a good base to work with. The main thing we are working on is the weird drop in power at 6500rpm that feels like spark blow out. We are switching over to a COP system and seeing if this fixes the problem. I am hoping to be in the 165 to 170 range when all is said and done.

I can't figure out how to get the damn graphs to overlay in WinPEP7 so here you go with seperate graphs.

Nice, needs VVT head. My manifold?

Too bad we'll never see it on the track. :giggle:

ITB's! lol i would love to have some of thoses and be all motor

Nice setup. What is the weight of your car? I still want to ditch my turbo setup and go ITB's.

This whole thing was supposed to be done a year ago and felt like it really never was going to be ready. I finally took a couple weekends to button up all the loose ends and took it to get tuned. Hopefully all goes well at a test and tune at TWS in May.

I may do that down the road actually. Yes your manifold.

The car should be around 1930-1950 lbs with a hardtop that has no glass. Scales are coming in next week so I should know for sure then

Have you thought about an adjustable cam-gear on the exhaust side. I remember (I think) an Emilio thread where he talks about the benefits on both the intake and exhasust, with most improvements on the exhaust side. Good excuse to grab a Protege valve-cover and expose that shiz. Double purple FM gears FTgayW.

Stock ignition setup?
Is it still 1.8 in displacement?

I am goingto look into the cam gears and see what I can come up with. I may be going with a whole different set of cams, but we will see. Thanks for the tip.

Stock ignition for now. I will be trying out the COPs I have on my back shelf to see if it eliminates the issue at 6500rpm.

The bore went to a 84mm, so should still be 1.8.

Just scored me a whole VVT motor for cheap, so I am gonna tear off the head and get it refeshed and a cam gear for the exhaust side. Soon I will have a second 99 head for sale, or I may just put it on the 01 bottom end and sell it complete. I really wish I had found this earlier, but what can you do. It's part of the reason I went with the Hydra.

For now I will run like this until I can get free time to do it all at once.

I like how your car makes more power than some turbo miata setups.

That is pretty good power.

I see you have a lightened crank. Do you have a stock balancer or an ATI. What flywheel are you using?

Stock balancer. Everything has a neutral balance so they are independent of each other. The flywheel is the FM 11 lb.

Steel flywheel?

Edit: What is your timing like?

Yeah th steel one for now. I am out of town right now but when I get back I will pull up my map and post it here.

I am interested in seeing it.

I think you are better off with the steel flywheel. Miatas have terrible harmonic issues, and seem to prefer the steel flywheels. You will notice that all twin discs use gutted steel flywheels. Hardcore N/A motors were beating up the bearings and one of the ways to cure it was to go back to the steel flywheels as well as using the ATI balancer.

One way to know if you are struggling with harmonics is to see if the motor is unresponsive or prefers lower timing than normal. This is assuming you have a pretty good handle on the fuel curves.

Before I knew better, I had a light weight pulley on the car, and the car would only run good at 32* total timing. When I put the balancer back on, the car liked a little more timing. It still does not like that much more, and I attribute it to the fact that I have an aluminum flywheel. Jesse Prather advised me to ditch the flywheel and get a steel one.

You have a lightened crank, which is not exactly ideal harmonics wise. If you see that you have a lower than normal timing and it starts to peter out, I would be suspiscious of harmonic issues and think seriously about a damper.

Just a hunch that your high rpm power may reappear if you solve any harmonics issues. It could however, be a combination of issues, with harmonics playing a small part in it.

The entire rotating assembly was balanced so I wouldn't think that harmonics is the issue. I wasn't aware of that with the steel flywheels though.

I had my rotating assembly balance too. Bearings were beat to shit when I pulled it apart. I learned the hard way.

Just something to think about if you think the motor is not reponding well to timing when it should.

Finally weighed the car and it came in at 1850lbs w/ 3/4 tank fuel. Corner weighting went well and for the 1 session I was able to do before being black flagged for noise, it felt really fast. I am very happy with it, but I may be moving on to another project now that this one is done. Who knows, this may be the one I keep for a while.

I feel cheated that I never really got to see this car run...I bet you feel even more cheated. I'll be back down in Houston later this year, lets try again.

Yeah I was pretty damned irritated, but worse things could happen. MSR-houston should be fun. I will be taking it out there a couple times here soon to give it another shakedown.