Quicker spool on challenge budget?

In reply to Boost_Crazy :

Do you have any links or articles or better explanation about making sure the flapper is centered and especially about shimming with washers and adjusting spring tension? I'm not even sure how to go about researching those to make sure I'm doing it right. Wrapping the exhaust and making sure of smooth transitions makes a lot of sense and will do while it's out before it goes in the good chassis

What MS variant do you have? The MSPNP Gen 2 or Pro are going to be the easiest to set up and best supported option. An MSPNP Gen 1 might still have more tuning options than what you have now but will not be nearly as easy to tune. A DIYPNP is similar to a Gen 2 in capability, but there are a lot of ways to build them and you may have to take it apart to figure out what's going on. MS Labs has built some interest pieces, but the company is one guy in Greece and there's less support base. A wire in system can be like Forest Gump's box of chocolates - but I may be able to take a guess at how much trouble it might be with some pictures of what's inside.

Miatas probably have the largest install base in the Megasquit world; Mustangs may be close. But this will probably have a larger number of people you can compare notes with than the last install you did.

In reply to MadScientistMatt :

Its (i believe) a diy pnp based off ms2. 

https://www.grassrootsmotorsports.com/forum/grm/identify-a-mspnp/271210/page1/

Id live to send it to someone to have it checked out before bolting in to make sure im not chasing my own tail if i decide to use it. Like i said, very nervous about megasquirt. Im also unclear if i can cook whats in the car with incorrect settings in the ms and cost myself extra money. Is that a valid fear?

In reply to Dusterbd13-michael :

In reply to Boost_Crazy :

Do you have any links or articles or better explanation about making sure the flapper is centered and especially about shimming with washers and adjusting spring tension? I'm not even sure how to go about researching those to make sure I'm doing it right. Wrapping the exhaust and making sure of smooth transitions makes a lot of sense and will do while it's out before it goes in the good chassis
 

On your car, you could get a good look at the wastegate flapper by dropping the down pipe. Here is an example of one that has shifted...

You just want to make sure that flapper valve is centered over the hole. 
 

As for shimming, you can add washers under the actuator where it bolts to the compressor housing. Some people have cut the actuator rod itself, threaded it, and added a turnbuckle to adjust the tension. I think the washers are easier, especially on your setup where you have great access. Start small, test, add as needed. You can test the effects of different shims without starting the car if you have a vacuum pump that also pressure tests. 

calteg said:

hater pipe out the hood  (also the name of my Sophomore album).

 

NVM, just saw the photo, no hood necessary. 

I was thinking about a screamer pipe and while it would improve efficiency it looks like one thing it won't improve is spool-up time.

You mentioned you're new to turbocharged cars--have you played with driving style? Left foot braking is free, and can be a fairly effective way to open the throttle mid-corner and start spooling earlier.

I'd still do my best to optimize the car before driving around the behavior. It wouldn't take much to get some decent improvement from where it sits now, THEN you can start messing with your driving style.

Can you describe what boost response is like now? I don't have any turbo Miata experience, but that turbo looks to be a good match for that engine, I wouldn't expect response to be an issue if everything was working properly. All of the supporting hardware appears to be in place, other than proper boost control. I'd lean towards making sure everything is correct first- boost control, ignition timing, fueling. Then look at things you could do to improve it. You really shouldn't be seeing any appreciable response issues unless you- 1) Are cruising along in too tall a gear and try to punch it below boost threshold or 2) come into a really slow 1st gear hairpin corner. Once moving at an autocross or on a track, boost should just be a tickle of the throttle away. 

OK, so that is a custom modified DIYPNP; it's hard to test these since any full test would require making an adapter harness specific to the unit. DIYAutotune generally doesn't test customer assembled items. Peter Florance at PFTuning.com may be able to check it over; he's a bit better set up for that.

In reply to Boost_Crazy :

Driving a MSM engine in an NA, I never wanted for more boost response.  It felt really good.  I think it was at 8 or 11-12psi when I drove it, with a manual boost controller.  Control was by an MSPNP and I don't know what he did for timing maps, but it never felt very laggy.  Power, usually too much, was always right there when you asked for it.

What I wished for was a working tach 

That turbo is a good size for the engine, but if there's some easy optimization you might as well do it! There's some real low-hanging fruit that shouldn't be ignored. Autocross is definitely sensitive to response, so a bit of work here would likely pay off. 

maschinenbau said:

Sounds like nothing a little 50 shot couldn't fix

I was thinking a scuba tank and a couple microswitches and a valve and a regulator plumb the thing in aiming at the turbo on the exhaust side. Virchally instant spool.  It will cool the exhaust but it is a crazy enough idea that I want to try it. 

In reply to dean1484 :

The turbine won't hate having cold air blowing on it when it's 1500+F?

Just because it hasn't been mentioned yet- boost leaks. Just about every DIY turbo setup has a bunch, and you can pick up a bunch of spool by fixing them. Check the PCV system- if you're running the stock PCV valve it's probably a big leak. Put a check valve inline or just cap off the manifold and vent the crankcase to a catch can. 

Dusterbd13-michael said:

In reply to captainawesome :

Nope! Just around the neighborhood still installed in the parts car. Not even making full boost, limited to 10psi.

15x8 on 200tw 225s is the plan. 

Im trying to optimize as i build, instead of having a bunch of rework. I may not need to, but....

I'm running an identical turbo setup on rock hard 15x9 R888's, albeit with a 5 speed.

Spool is pretty darn quick and I don't have traction in 2nd gear, likely due to the rubber

In reply to ShinnyGroove (Forum Supporter) :

PCV valves if working should be check valves.  They shouldn't flow backwards.  This dates back to the 60s when they were on carbureted installations and an intake backfire could cause a HUGE mess if it got into the crankcase.  (Poof)

Good thing to check though!

Pete. (l33t FS) said:

In reply to dean1484 :

The turbine won't hate having cold air blowing on it when it's 1500+F?

It will probably explode but that would be half the fun. 
 

Ok so maybe try aiming it at the intake turbine?  Just a quick blast to get it spooled and have it tied to a extra injector to keep the AFRs in check. 
 

Or inject some acetylene just before the turbine on the exhaust side?  What could go wrong. 😁

I have all sorts of bad ideas. 

In reply to dean1484 :

You could route a blowoff valve to the exhaust manifold through a check valve, too.  This can get very concussive and turbo life is shortened a lot.  And if you have shim over bucket OHC, the exhaust pressure might pop the exhaust valves open while on the base circle and you can lose a shim, which has no good aftereffects.

Are you feeling lag?

I honestly didn't notice any appreciable lag when driving it. It felt well matched for the engine size (which is bored out a bit). 
 

That's part of what got me in trouble with the car. It responded quicker than I was able to handle. 

As an aside, I have a lot of misgivings about the recirc valve setup.

All arguments against their use in general aside, the valve is plumbed on the turbo exit.  This means when you close the throttle and the valve opens to release all the pressure you spent all that effort building, the air mass in the intercooler has to stop and change direction.  When you reopen the throttle, it will have to change direction again to start feeding the engine.  Forcing air to change direction or even just change speed requires energy and that energy comes from somewhere.  It's a momentary loss but improving response is all about removing momentary losses.

It also looks like the valve recirculates in such a way that it points away from the turbo inlet, not towards it.

While my knee jerk instinct is to take the recirc valve off and install it in the nearest trash can, if you want to keep it, you would do well to put it on the plumbing between the intercooler and throttle body, so airflow is always moving forward whether it is going to the engine or out the valve.

I'd also see if it's possible to reorient things so that when the air is reintroduced to the turbo inlet that it is aimed in the general direction of the turbo, not the MAF.

Paul: definitely laggy. Seems to not make any boost or power till aboutv3500 or so. And then its very abrupt. Not linear. 

Pete: the recirc is currently hack, even for me. But itvwas a quickybwith whatvi had on hand. I like your thought process, and do plan to keep it amd ill take your advice. 

Calteg: i have 6 year old rock hard rivals on 15x7 and no traction issues. Which it seems like i should, even at only 10 psi. 

Shinnygroove: thats a distinct possibility with boost leaks. I haven't checked. 

Everyone: its sounding more and more like ive got some more sorting to do on the setup before i chase improvements.  Apparently its not behaving the way it should yet. Which explains why i was trying to modify it to fix it! Thanks everyone. I truly appreciate this.

It should definitely be doing something below 3500.

I like to keep "lag" and "boost onset" separate.  Lag is how long it takes for the turbo to wake up after you request power.  In more extreme cases, the turbo lags so far behind engine acceleration that it doesn't build much boost in lower gears.  I used to have a boost by MPH chart of an Audi ur-quattro where it didn't build full boost until 3rd gear.   The engine accelerated faster than the turbo in first and second gears.

Boost onset is just the size of the turbo vs the airflow of the engine. 

I have a car that will make boost at literally any RPM that I care to, but when I mat the throttle I can count one-one-thousand two-one*16psi*.  That's lag  Can drive around that by holding the throttle slightly open before matting it, to get the juices starting to flow first.

You should definitely have boost onset below 3500.  When I was driving aforementioned Miata, I accidentally saw 18psi in top gear on the highway.  Immediately called to confirm boost settings... no, it's supposed to be lower than that.  The mechanical controller was stuck shut.  But it was definitely happy to build boost at lower engine speeds.

Pete. (l33t FS) said:

In reply to ShinnyGroove (Forum Supporter) :

PCV valves if working should be check valves.  They shouldn't flow backwards.  This dates back to the 60s when they were on carbureted installations and an intake backfire could cause a HUGE mess if it got into the crankcase.  (Poof)

Good thing to check though!

Next time you have a stock Miata PCV valve in your hand, blow/suck through it. I think you'll find that it doesn't work like a check valve at all. I went down this road with many different OE-style PCV valves, they all leaked significant boost into the crankcase when the manifold pressure went positive. I was tuning with MS2 at the time and the data was pretty conclusive that capping off the cold side PCV system helped pretty dramatically with spool. Positive pressure in the crankcase isn't exactly ideal either. 

In reply to Pete. (l33t FS) :

Looking at the pic again, the recirc valve looks like it's plumbed backwards to me. Every one I've seen has the  diaphragm and valve perpendicular to the pressurized pipe, and bypasses out the side to the intake. That one looks like it's flipped? 

It is odd to see it pre I/C, but it should still work fine. I don't see how no valve would be an improvement. With no valve, the air charge would still reverse when it hits the closed throttle plate, but it would also reverse through the spinning compressor. Best case you slow/stall it and have even more lag, worse case you snap the shaft. 
 

35oo is way to high for that engine/turbo combo. My Galant VR4 spools just under that, with a much larger turbo and a low 7.8-1 compression ratio. 

Went to an e gate recently, it spools so hard we are having trouble with mild over-boosting getting the gate to react quick enough once we hit target. It stays closed far longer than a traditional gate from what I can tell. Could rig that up with an OEM e gate?