After street driving, two autox's and a night at the dragstrip all is good.
A few notes:
-The cheap ebay T3/T4 is awesome. Boost onset is in the 2500 range and is very docile driving at low (sub 4k) rpms. I think the full 3" exhaust has a lot to do with the early spool. 10psi feels really good.
-The full 3" exhaust is near silent - until the vta wg opens, then it's another story.
-Best mileage on an 85% highway loop was 33.0mpg.
-With huge lag (more on this later) between shifts and 195/60-14 Fuzions, it wheelhopped (more on this too) to a 1.99 60' and a firstname.lastname@example.org. 602', hot and humid. Weight was 2570lbs going down the track. In NA trim it was 2400lbs. Apparently I added a lot of weight. The hp calculator showed that if I didn't have the big lag between shifts the hp vs weight should have netted a 12.93. This is around 9-10psi, not sure, didn't datalog. I'll go back to the track after I fix the wheel hop.
-The wg signal was being referenced to the tap on the turbine. There were times when the wg was opening as I was lifting. Changing the reference to the manifold solved the issue and between shift lag is almost nil.
-The bov is open at cruise. I think it is the culprit for my unstable cruise afr's. I might add a solenoid to the bov signal line and cut it when I'm in closed loop, let it operate normally in all other conditions.
-I get massive wheel hop at the drag strip and when launching at the autox. I have some urethane differential mounts on order, I'll report on how they do.
-Vented hoods are not pretty or stealthy but the functionality makes up for it.
-So far, no cracks and no failures of any of the cheap ebay chinese turbo, intercooler, bov, wg, manifold. The turbo and wg are braced.
-Can't wait to turn the boost up but won't until I have more details on what it takes to put the RX-7 trans guts into the Miata. If anyone has done this, please steer me to the info.
I'm about to order my own oil feed line for my 97 and I am curious about how long it needs to be to run from the oil pressure sensor to the turbo. Is 48" overkill? I just wanna know the approximate length before I order.
I used 47" and It is a little long. If i was going to do it again I would make it shorter but just because I don't like clutter. I advise paying the extra money for swivel fittings on the line because it has a permanent curve in it and it doesn't like to bend. If you tighten it down a certain way it won't like to bend the "wrong" way. The swivel fittings solve that problem.
I'd move the filter off the turbo inlet or at least cover/shield the turbine housing. You're sucking in really hot air right off the bat.
That was the original temporary setup. The current temporary setup has a large enclosure that seals the air filter to cold air coming in through the TSI and the sometimes sleepy eyes. It's hard to spend the time to do something nice when the temporary setup keeps working - and you have a million other things to do.
There is some heat shielding installed now, just need more.
The eBay knockoff HKS SSQV BOV was replaced with a REAL 2007 new generation HKS SSQV BOV. Huge difference in operation. Besides the fact that the knockoff had catastrophic failure and leaked all the time, even when new, it vented at idle at full preload. I thought this was how things were supposed to work.
After installing the new HKS BOV (which has NO spring preload adjustment) there is no leak at idle. Boost comes on earlier and doesn't drop off nearly as much between shifts. It vents a LOT less than the knockoff.
Knockoff: $93 shipped
Real: $184 shipped
The BOV started leaking badly while I was playing with cam timing so the thread that I was attempting to report my results is pretty much invalid.
Why did you change around the feed and return in your fuel rail?
Good point. I was caught up in 'internet legend'. It takes the same amount of time to feed the rail from the back or from the front when you have a remote fuel pressure regulator. Since whatever cylinder is on the end of the rail seems to be the toasted one I decided to feed it from the end of the rail (#4 in my case) that the inlet is inline with the rail and the outlet is 90° to the rail, which seems to be a restriction. No hard data to back anything up, just did it that way.
Originally Posted by m2cupcar
Do you have any datapoints for your "spool" before and after? Definitely see the potential of a leaking bov could go undiagnosed- especially being the first time for the setup.
Real datalogging wasn't working before. Power wise, before the massive leaking happened, you really couldn't tell. Standing on the gas at idle in first gear would spin the tires (1.6 aluminum flywheel), a third gear roll on would spin the tires. Hard to tell I was down on power.
I only drove it a couple miles to test the BOV but boost comes on more linearly now. Before it would hit like a sledgehammer, probably the BOV being forced shut.
I think I saw 10psi @ 3400 in 4th, around 3900 in 2nd - things are happening fast so it's hard to say. I need to do some real datalogging, have to load some software.
Bottom line: a leaky BOV is not good and a slightly leaky BOV can really trick you.
I forgot to post about that. After deciding to not go with delrin on the rear diff mounts I found someone who attempted to get me a set of urethane bushings from Japan. Never happened. I ended up going with the Mazda Comp diff bushings. The lower steel spacer that goes between the PPF and diff housing was broken. Not sure if this was the cause or the effect.
Wheel hop is greatly reduced but not completely eliminated. It used to be really bad.
If it's really bad the next time I go to the dragstrip I might put some effort in to figuring out what's really causing the problem.
awesome vid too much fun
That clearly illustrates why you don't run a big turbo on a little engine for optimum autoXing Makes for a hard day at the office - but it looks like predicting the boost "rocket" is second nature now... at least most of the time.
looks like a lot of fun, i cant wait to start seeing buust, i will havea similar set up, older versiond but real HKS bov and a t3t4 churbo...not going with that mani though
so you see boost as early as 3K, very promising, thats what i was hoping for with a 3" turbo back