92Black&Tan

iTrader: (2)

Well if any of you remember the last time I went to the dyno it was a total waste of time. I had a huge lean spike and I was pretty pissed at myself. I should have gone ahead and bit the bullet and done all of the band aids, but I can be stubborn and was trying to incrementally piece together each piece and just see what it will do. Needless to say, when trying to up the boost on a Greddy go ahead and do injectors, fuel pump, O2 clamp and Bipes and be done with it. [Unless of course you are going with a stand alone or piggy back.]

Anyway... On to today's story. I was at Miata tech day and a couple of the other turbo guys were going across the street to the dyno and I thought I would tag along just to see what their cars would run. We had time for a few extra runs and I wanted to see if the Walbro 190hp, 1.8 injectors, and the new 8:1 disk in the Vortech did the trick. Well suprizingly... I was way rich now, and only about 135rwhp. [Before I started and only had the bipes I was at 145rwhp/145rwtq]

Well... I didn't bring the other disks with me [I probably need the 6:1] so we decided for fun to put a small tube with 3 tiny holes drilled in it in the vacuum line feeding the FPR. And guess what? It worked perfect. The A/F is great. So then we proceeded to crank up the boost a little and lo and behold I left with a safe 177rwhp/177rwtq. [Oh and by the way, the ambient temperature was 103 degrees... Yeah, that's right.]

All I wanted was a decent A/F ratio and now I have 177/177 on tap and i am pretty stoked. I just thought I would share with someone who would understand what the hell I am talking about.

Here's the set-up just in case anyone is taking notes for their own build:

Stock motor with 150k miles [All synthetic fluids]
93 Octane Chevron fuel
Used Greddy kit with relief cuts in manifold
Custom intake
Custom RX-7 intercooler set-up
Bipes [Pulling 1 degree of timing for every 65 degrees of intake temp and pulling 5 degrees of timing between 3000rpm and 4000rpm.]
Older Guy's O2 clamp
1.8 liter Miata injectors
Vortech FPR with a 8:1 disk and a little bleeder on the vacuum line
Walbro 190 lph/hp fuel pump
VooDoo Manual Boost Controller
NAPA Cat
OBX Stainless Dual Exhaust

So anyway... That's about it. I'm pretty happy right now. I am going back after I either put a spacer on my wastegate or a helper spring or both to prevent the boost from bleeding off after I reach peak. And after I put in a little stronger clutch. The consensus of everyone at the dyno was that I should be pushing about 190rwhp if I would come back when the temps were closer to 60 degrees. I don't know how many of you live down south, but 103 is freakin' HOT.

magnamx-5

iTrader: (7)

Cool beans dude i am glad you got your **** right. Now you can bite the bullet and build a homedepot lowes mbc and dial in the fpr like that as well. Still great job what are you at now 8 psi?

92Black&Tan

iTrader: (2)

Well... You know... That's the weird thing. The vacuum line that feeds the FPR branches off before the homemade bleeder valve and runs into the firewall. Then it branches off under the dash to feed the boost gauge before it feeds the O2 clamp. So I am wondering if the boost gauge is affected by the bleeder valve after the tee connector? Why do I say that? Well because it is only registering about 6-7 psi at the peak and then it tapers off to about 4-5. And I know I can't be making that kind of hp/tq to the rear wheels with that kind of boost.

So the next thing I am going to do is to hook up the vacuum lines separately and hopefully see what boost I am really running. I am also going to take a small piece of the 1/8" flat bar stock and make a 1/8" shim for the waste gate and see if it can hold the boost a little better after it peaks at about 5000rpm.

92Black&Tan

iTrader: (2)

OK guys... Here's some graphs for you to view...

One graph is a pretty neat history of my turbo build:

http://forum.miata.net/vb/attachment...chmentid=48142

The green lines represent the baseline dyno on my car. It made a pretty decent 97rwhp/97rwtq after some tuning, which is pretty indicative for a stock 1.6 liter Miata in a proper state of tune.

The blue lines represent my initial Greddy installation. I was able to get 145rwhp/145rwtq right out of the box with no tuning. Of course I installed an RX-7 intercooler, custom intake, OBX dual exhaust and a NAPA cat at the initial turbo installation. I also had the waste gate tightened all the way down, and we tweaked the AFM clock spring a little to get the fuel mixture halfway decent. So don't expect to get those numbers from a basic Greddy installation. The intercooler kept me from having to retard the base timing to some ridiculous number.

The red lines represent yesterday's dyno pulls. In addition to the above paragraph I have added an O2 signal modifier, a Walbro 190hp, 1.8 injectors, and calibrated the Vortech FPR.

The other graph:

http://forum.miata.net/vb/attachment...chmentid=48143

... Shows the same max values and also shows the A/F ratio. I'm sure some will critique it. It runs a little rich after about 5250, but I'm pretty happy with the numbers and the tune right now. I could spend thousands more and hours and hours of tuning with a laptop on a stand alone ECU, but for what I have spent [About $1600 on the installation this far] I am pretty happy. Best of all it still has stock driveability... With just a bunch more power. Going from 97rwhp to 178rwhp is a BIG difference and really transforms the "cute little sportscar" [to quote others] into a real serious sports car.

Anyway... I'm pretty happy and hopefully, I can leave the thing alone for a while and just drive it and enjoy it.

Braineack

iTrader: (62)

youd be happier if you're boost didn't plumet like it does and a new DP was utilized.

92Black&Tan

iTrader: (2)

Happier? How could I be any happier? True happiness comes from within.

But regarding the turbo making a better power curve...

Yes... A bigger/better downpipe, a new uber, super, heavy duty, clutch and a shim and/or a helper spring are all on my list of things to do soon. I think the shim/helper spring will help keep the boost from bleeding off in the upper rpm ranges. I think the bigger downpipe will help build more boost sooner, and the clutch will help me tear up my transmission and rear end sooner.

Braineack

iTrader: (62)

yes, the DP in your case will most likely show you 500RPM sooner full boost.

The helper spring will help keep the differential between you boost spike and drop to a minimum, increasing your top-end HP substantially.

Let's say that a helper spring was able to prevent your boost drop enough to keep the TQ at 7K to 150tq. Something very plausible.

If that's the case then your HP would be 200rwhp, with the same peak torque of 172...


fwiw, a shim wont do anything like a helper spring will do...the problem is the diaphram is weak, so you spike high and drop fast (as the boost simply overloads the thing.....the helper spring helps prevent the overshoot and helps maintain a flat boost level throughout the revs.

92Black&Tan

iTrader: (2)

I have read quite a few threads about the helper spring. Has anyone ever actually posted a part number of an actual spring that they have used that works? I am going to use an eyebolt for adjustability, but it would be neat to at least have a starting point for the spring.

zbossrt

i would be interested in the "helper spring" I get boost spikes and drop offs. I beleive that i am at 7psi and dropped off to 6psi constant. if there is info on where to get this helper spring and pictures of people who have already installed it, that would be great!

greenday3437

iTrader: (2)

http://forum.miata.net/vb/showpost.p...85&postcount=1