PAdutch's misadventures in Miataland

[rocknrace03]

mmmm itb porn

[DocWalt]

Thinking about it, I didn't realize ITBs were CSP legal.... or was this going to SSM?

[PAdutch]

Originally Posted by DocWalt

Thinking about it, I didn't realize ITBs were CSP legal.... or was this going to SSM?

When people ask me about rules I always go back and check because I question myself:

15.10.c.1

C. Induction allowances are as follows:
1. Carburetors, fuel injection, and intake manifolds are unrestricted subject
to Section 15.10.D. Alternate throttle linkage and connections to
facilitate installation of allowed induction systems are permitted but
may serve no other purpose. If an induction system item is allowed to
be removed and its original mounting bracket can be removed by simply unbolting it, the bracket may be removed as well

Others have run ITBs in street prepared.

[PAdutch]

I have also noticed that many of the ITB miatas run 75mm long velocity stacks. The ones that I have are 100mm. That 25mm of clearance will probably fix my problems but I may just go to 50mm to be safe.

Long velocity stack = low end performance
Short velocity stack = high end performance

Id rather have the low end torque but i just cant see it working out. For now its stock intake mani.

[DocWalt]

Originally Posted by PAdutch

When people ask me about rules I always go back and check because I question myself:

15.10.c.1

C. Induction allowances are as follows:
1. Carburetors, fuel injection, and intake manifolds are unrestricted subject
to Section 15.10.D. Alternate throttle linkage and connections to
facilitate installation of allowed induction systems are permitted but
may serve no other purpose. If an induction system item is allowed to
be removed and its original mounting bracket can be removed by simply unbolting it, the bracket may be removed as well

Others have run ITBs in street prepared.

Thinking about it, I know the BSP winning car has ITBs. I just never really thought about it, lol. I'm trying to avoid thinking about SP class cars and Hoosiers lol

Originally Posted by PAdutch

I have also noticed that many of the ITB miatas run 75mm long velocity stacks. The ones that I have are 100mm. That 25mm of clearance will probably fix my problems but I may just go to 50mm to be safe.

Long velocity stack = low end performance
Short velocity stack = high end performance

Id rather have the low end torque but i just cant see it working out. For now its stock intake mani.

Even if the extra 25mm gets you clearance that last stack looks like it may still be starved for air. Maybe you could get a phenolic spacer or something to angle the entire ITB assembly upwards?

[PAdutch]

Originally Posted by DocWalt

Thinking about it, I know the BSP winning car has ITBs. I just never really thought about it, lol. I'm trying to avoid thinking about SP class cars and Hoosiers lol



Even if the extra 25mm gets you clearance that last stack looks like it may still be starved for air. Maybe you could get a phenolic spacer or something to angle the entire ITB assembly upwards?

Purple Crack is where its at

I've thought about creating some kind of angle, I just cant work out the bolting in my head. I also considered designing a curved or angled velocity stack and 3d print them. I'm not sure where I would find the time for that right now and would be afraid of doing more harm than good.

[PAdutch]

The Engine is back in, this time with less ITB . I have basically everything complete and was planning start it last weekend but had unexpected visitors thanks to the snow storm. I did crank it and it built oil pressure nicely so that made me feel good.

One thing I have been ignoring is the ignition coils. The old coils don't bolt to the new engine so and the engine I bought was missing a coil pack. The VVT coil packs need a rewire to work in the NA but that is my plan at the moment (coil pack on order). For now I will try to start it with the old coil pack rigged in there.




I also started on my new control arm bushing concept. The idea is to move the front wheels as far forward as possible to add rear clearance for the 15x12 wheels. These are double offset upper control arm bushings that should increase camber, as well as, move the wheel forward ~.150". The forward movement should be adjustable with different center bushings allowing me to fine tune caster.


I also got around to making new rear upper spindle bushing which allowed me to install the ABS spindle.



Hopefully this weekend the engine starts and most of the suspension is back together. Another snow storm is on the way though

[PAdutch]

The smoke in the picture is from a running race car. I now have the VVT engine starting and idling pretty nicely which means I need to get the rest of the car back together so I can tune it. At this point I feel pretty good about it.

Good enough that I signed up for the Pittsburg Match tour. My first national level autocross.

[DocWalt]

Awesome! Congrats on running car.

You camping for the Match Tour or nah?

The site is odd, grip varies between sections of lot a bit when dry but if it's wet or even just damp it's a **** show. I would go from 1.1G one corner to 0.9G in the next. Other than the weird-ass pavement, the facility is really nice. 24/7 hot showers and bathrooms, great karting track (bring cash if you want to do this. last year it was cold and wet and miserable so nobody did it), there's race gas on site for typical pricey race gas prices idk about E85 though, there was a food truck last year that served breakfast (though a hair later than I would like so I ran to McDonald's in the next town over) and pretty good lunch

[PAdutch]

Originally Posted by DocWalt

Awesome! Congrats on running car.

You camping for the Match Tour or nah?

The site is odd, grip varies between sections of lot a bit when dry but if it's wet or even just damp it's a **** show. I would go from 1.1G one corner to 0.9G in the next. Other than the weird-ass pavement, the facility is really nice. 24/7 hot showers and bathrooms, great karting track (bring cash if you want to do this. last year it was cold and wet and miserable so nobody did it), there's race gas on site for typical pricey race gas prices idk about E85 though, there was a food truck last year that served breakfast (though a hair later than I would like so I ran to McDonald's in the next town over) and pretty good lunch

I'm considering camping but I'm a little worried about the temps. The wife will be with. Ill probably decide when it gets closer.

Sounds like conditions really affect traction. I'm hoping for warmer weather, otherwise Ill never get any heat in the tires. I will have a codriver. At that point I will only be tuned on 93 I'm sure so race gas or E85 probably wont help. I may partake in some karting.

On another good note. last night I put the finishing touches on the front passenger side suspension. It looks like my special bushing are going to work as intended. I still don't know exactly where it will fall camber/caster wize but will be slightly tuneable by swapping out bushing centers and move the wheel forward to help with clearance of the new wheel/tire.

[DocWalt]

I camped last year. It wasn't really all that warm... I survived but I'd take a heavier sleeping bag than the summer bag I took last year. I just saw your posts on sandbox, so I see you've heard about the "interesting" surface out there, haha.

[PAdutch]

I have been battling a pretty major electrical issue with this thing and am concerned that I wont have it ready.

My TPS signal seems to have an issue I cant figure out. I calibrate the voltages in tuner studio for 0% and 100% throttle but if does not stay. Weird thing is while sitting the throttle position in tunerstudio will creep up away from zero and once i move the throttle a it gets all messed up. Never setting back to zero sometinmes negative sometimes positive. My worst nightmare, an electrical issue.

[DocWalt]

I assume it's a three wire TPS? Sounds like the TPS ground reference is floating. Is the TPS 0V fully connected to the sensor ground pin on the ECU side?

[PAdutch]

Originally Posted by DocWalt

I assume it's a three wire TPS? Sounds like the TPS ground reference is floating. Is the TPS 0V fully connected to the sensor ground pin on the ECU side?

Yes its a 3 wire. I was suspicious of the grounding as the 01 VVT engine does not have the same grounding points as the 93 car.

As stated below there seems to be some level of conductivity between the 5v reference and the ground when the ecu is plugged in which I don't believe should be the case.

Post I made in miata turbo forum:

1993 Miata
MSlabs MS3 - bought used
VVT engine swap - using VVT mega thread method
LC2 Wideband
2001 TPS, Throttle and intake manifold

Symptoms:
1. Sitting at steady state the throttle position will slowly climb in tuner studio without touching the throttle. Meaning I calibrate it to 0% and slowly it climbs to 10% or more. This happens running or not running.
2. With a very slight movement of the pedal it will drop to nearly -30% throttle position before traveling to 100%.
3. Once the throttle is depressed it rarely settles back to 0%, sometimes sits as high as 30% in tunerstudio.
4. With the megasquirt unplugged resistance between ground and the 5v supply is 4400 ohms. With the ECU plugged in resistance drops to 770 ohms when measured at the TPS connector.

Things worth noting:
1. I first though it was a grounding issue so I have put a ground on the driver side from the exhaust manifold stud to the chassis and a ground from the intake mainifold to the chassis. Neither made a difference.
2. I have bought two cheap autozone TPS as well as the one that came with the engine. All have the same symptoms.
3. I did turn the key to the on position a couple of times with the ST sign fuse in before I realized what I was doing.
4. Was a good running car perivously with a NA 1.8 engine swapped and

Did I damage the megasquirt when I didn't pull the fuse? How do I verify this?
Could it be my wiring harness? Could I have spliced something in wrong?
Should I ground it a different way?

I have attached my tune and a couple of logs if anyone wants to take a look.

I would really appreciate any advise.
Thanks ahead of time.

[PAdutch]

So apparently I have been wanting to do dumb things lately:

1. The TPS was a stupid wiring issue. The ref and signal wires were switched. It is working well. That's what I get for blindly following an internet post. Changing wires solved that.
2. In dealing with the TPS issue, I had run the car out of fuel but thought it was a fuel pump issue. Adding gas solved that.
3. Continued start attempts with low fuel level lead me to foul the plugs which I didn't realize quickly. Changing plugs solved that.

After all that the car was starting and idling nicely yesterday. I welded up a quick CSP legal exhaust to quiet it down a bit:



Its not pretty but given the harbor freight welder and my abilities, Ill take it.

Hopefully tuning this week and maybe getting out autoxing this weekend. That's a big maybe.

[DocWalt]

Good luck! Glad to hear you got the issues resolved.

[PAdutch]

Took the car for a drive last night and it felt pretty good. It was pig rich but felt strong. Much better than the previous engine. Attempting to get to an autocross this weekend.

Tuning with tuner studio/megasquirt is very easy. The autotune function is nice.

[DocWalt]

What sort of AFRs are you targeting for WOT?

The hardest part of tuning Megasquirt on my car was the cold start, idle, and transient throttle behavior (acceleration enrichment). I'm not even using the fancy pants EAE yet... maybe if I ever do ITBs so it runs properly.

[PAdutch]

Originally Posted by DocWalt

What sort of AFRs are you targeting for WOT?

The hardest part of tuning Megasquirt on my car was the cold start, idle, and transient throttle behavior (acceleration enrichment). I'm not even using the fancy pants EAE yet... maybe if I ever do ITBs so it runs properly.

WOT AFR target is 13-13.2

Yeah I'm still struggling a little with cold start. It cant seem to find its rpm right away and stalls from idling at to low an rpm sometimes. I think it might just be some VE smoothing that's needed.

Once idling it is pretty good except with quick throttle let-off. It wants to idle a a low rpm before it settles.

I thought I had accel enrichment's pretty good but the changes in my VE have made them a little rough, some tuning to do there.

I have no idea what EAE is. I just looked at the settings in TS and it is intimidating to say the least. I have some research to do I guess.

[DocWalt]

If the car reliably starts and idles that's a huge first step. VE smoothing helps a lot with idle. Try to make the cells in the idle area result in the exact same injector pulse width. Also, bump up ignition timing a bit below idle RPM or use the idle ignition advance feature to smooth it out. In my experience ignition timing doesn't help stabilize idle well when cold but when hot my idle valve's position barely moves and everything is corrected using the idle ignition advance.

Are you controlling an idle valve with the MS ECU?

Accel enrichment shouldn't be affected too much by the VE table once you get the VE table dialed in.

FYI the auto-tune stuff is great for getting the VE table pretty close, but it manages to screw up my idle royally every time so once you get the idle tuned lock those cells! Same for WOT, it gets it close but once you fine tune by hand lock the cells. It's really good at cruise and normal driving around stuff but some fine tuning may be needed.

Don't worry about EAE if you don't know what it is. It's Enhanced Acceleration Enrichment and factors in wall wetting and fuel puddling and blah blah blah.