eurojulien

iTrader: (1)

Hello MT,
I've recently purchased a 2004 MSM with several mods and I have some questions about what direction to go in.

The car has an AEM intake, Chip Torque (BEGI) Flash, Goodwin MSM->NB Downpipe, 2.5" center section with 100cell race cat, some custom made muffler delete section (it's really nice and pie cut, wonder who made it) some ebay clutch that can hold decent power, CX racing intercooler, Forge (copy) recirc Valve and a hallman MBC. Currently boost is at 9ish PSI @5000ft.

Here are my questions/concerns:
- I put the OE DP on the car to pass emissions and the threads on the elbow are ruined. Not sure I can swap the DP again before taking the elbow off the turbo and putting new studs in. How much boost would be reasonable to run with a factory DP?
- I am installing an innovative SCG-1 Wideband/Boost controller to get a better idea where my AFRs are with the current flash. Also as a safety measure to cut boost if AFRs get too lean.
- My plan is to ship the ECU back to Australia to change the tune to 440cc injectors (RX8). It's not too expensive and why not sort of thing. From my understanding this will provide decent fueling but I will quickly come to the limit of my MAF which is around 12 psi.

Here are some ideas I'm kicking around
- BNR Upgrade (will this improve spool at all or only increase top end? been trying to get them on the phone)
- Blouch Upgrade (won't improve spool, will essentially copy old big enchilada setup but with better fueling)
- FM Garrett conversion (better spool, nicer plumbing, can sell off current bits to offset cost)
- Keep stock turbo (was rebuilt 10k? miles ago). From my understanding 12PSI with a factory turbo != 12 psi with a garrett or upgraded compressor wheel, something about total volume of air? Does the 12PSI limit on the factory MAF even matter if I'm monitoring AFRs and they stay =<12?

- Get FM Downpipe (current 100cell smells a bit and fits a little jankly)
- Hot swap the ecu with MS3 keeping the 440cc injectors in place down the road if factory ecu with CT tune isn't cutting it and I want to run more boosts


I know this list doesn't make a whole lot of sense without goals, so here they are
- 12 PSI with hopefully ~210? rwhp. I had a NA with an FM2 and it felt lovely at 12 PSI, ended up at 14ish PSI and 230whp. loved it!
- A fun project. Swapping turbos and tidying stuff up in the engine bay sounds like a nice way to get to know the car
- Value: I don't want to pump a bunch of useless $$ in the car that will eventually reduce it's resale. That's why keeping it ODB2 compliant and passing sniffer test is attractive. Maybe that's the old me who lived in California though.


Any ideas welcome. I've googled/searched a bit but haven't found a clear path.

Thanks!!
Julien

Engi-ninja

First of all, nice shop setup.

Secondly, in my opinion (and I think most people here will agree) trying to keep the stock ECU is so limiting that it'll take most of the fun out of it. Not having the ability to tune to your specific setup means no matter what you do, you'll never be able to utilize the full potential of whatever setup you end up with.

I would probably start with swapping in an MS3, tune to the limits of the stock turbo, and go from there. Embrace your freedom from the communist nation of California :-)

eurojulien

iTrader: (1)

I'm trying to wrap my head around target boost pressures at altitude. If the stock IHI maxes out around 15 PSI at sea level, wouldn't that make it closer to 12? psi at 5400 FT with trips up to 7-10k feet?

quick mafs:
1000mb (or 1 atmosphere) at sea level, 850mb in denver = 0.85. So 0.85x15 psi = 12.75
If I go to Nederland for some bbq that 8,000 feet or ballpark 750mb. 0.75 x 15 psi or 11.25 psi.
or worse pike peak 14,000 ft 590mb = 8.85 PSI! or in other words overspooling the safe limit by 1.69x (nice) or 25psi at sea level.

random example I found online:

Jesse99James

I too think an aftermarket ECU should be the first step if you don't have to deal with emissions. My MSM had the FM2 Garrett upgrade installed back in 2010 by the original owner. The Hydra Nemesis 2.6 had a tune that survived many track day but didn't start well cold or on hot restart. I made some progress on the tune but the software was very dated, not as easy to use as the 2.7 version and my upgrade attempts failed (had to be a hardware upgrade and Hydra is no longer in business).

I knew this going into the purchase and replaced it with an MS3Pro PnP. Mine also smelled strong as it was randomly running overly rich during cruise and idled far too rich it was basically a rough race tune without much follow up tweaking done from what I saw in comparison to the base tune. FM did a great job with their base tune but after the MS3 tune started to come together, the smell is almost gone. I thought like you that I would have to replace the cat.

I've never experienced an OEM MSM but the GT2560 feels great, falls off a bit after 6k RPM but 11-12 psi was strong. I am close to assembling a built engine so I can run closer to 16-18 psi and think that'll be enough with 3.63 gears. I doubt I'll upgrade the turbo and 2.5" Magnaflow exhaust. Gotta run, hope this helped your decision!

Engi-ninja

I'm not sure scaling the pressure that way is the way to look at it. My understanding is, for a given wg pressure, the turbo will spin faster at high altitude in order to achieve that pressure than it will at sea level. So you need to size your turbo larger to achieve the same pressure at a reasonable shaft speed.

The graph you posted has pressure ratios on the vertical axis, which is the ratio between the inlet and outlet of the compressor. So it's saying that as the pressure ratio increases (i.e. achieving a given intake pressure as atmospheric pressure drops), the turbo has to spin faster to make the same mass flow rate. The green line is the shaft speed required to achieve a certain mass flow rate, at sea level, which is lower because the air is denser. The blue line shows the shaft speed required to make the same mass flow rate at higher altitude. At sea level the turbo is oversized for that flow rate (which corresponds to a certain power level), but at high altitude, it's better suited.

Someone correct me if I'm mistaken here.

Gee Emm

Dunnunda MSM owner modifier here.

Bought my car needing work, particularly clutch and exhaust. See my build thread, link below. Currently rebuilding because Bent Rod(s).

My first moves were making the car legal and getting rid of dodgy clutch, followed by new ecu. That facilitates more power, and gets rid of the famous 'bog' problem. Forget the reflashing, it is logistics heavy and inflexible, especially from over there. That was the fundamentals, rest was tweaking.

My build (mainly road, a few track days) will be fully built engine (all forged) including a China 2860 on a Kraken manifold, injectors and Boundary oil pump, maybe another clutch since the engine is out.

Like to go on a bit but like Jesse gotta go - I have an 800km drive in front of me today.

eurojulien

iTrader: (1)

So far the TC is flash pretty reasonable, no noticeable bog. Once I have my wideband I'll start looking at AFRs. In regards to the reflash it's $300 with shipping, so why not sort of thing.

Crarrs

iTrader: (1)

The "why not" is that you're stuck with that tune unless you ship it back to them, and then your car is down waiting for the ECU to come back, and you hope that they got the new parameters right because they don't have actual data logs to base their changes off of. MS3 is the way.

eurojulien

iTrader: (1)

Out of the last 4 miatas I've owned, 2 had megasquirt, 1 had link. This car will eventually get MS3, no worries there.

Lokiel

ChipTorque are great and cost-effective IF you have ALL your hardware finalised AND they have a tune that suits it, which is why they recommend limited upgrade options to you (ie. they'll recommend only what they've worked with on actual cars in the past).
They may be prepared to "have a crack" at coming up with a workable tuning for you with your "modz" but that may require you sending the ECU back and forth a few times until you're happy (and each time will cost you same amount of $$$).
IF you're happy with the power output that ChipTorque can provide with their existing MSM tunes for specific hardware "modz", AND can fit that hardware to your car, it's a very cheap option that will pass emission testing.

This is the MSM OEM downpipe:

MSM OEM downpipe
Note on the RHS that it's pinched at the flange to about 2" ID and opens out to 2.5" ID AFTER that.
This means that the MSM OEM exhaust (and the FM MSM upgrade exhaust which has this limitation too since it mates to the same turbo exhaust flange) is choked at that point - restricting flow (which is BAD).
This is just one of many half-arsed things Mazda did with the MSM that got it to market quickly but crippled it from the factory (mot likely to preserve the RX7/8 as the performance car and not embarass the "to be released" N/A NC).
ie. You can better than the FM MSM OEM downpipe (which I'm not sure they even make anymore).

DON'T make any decision on the exhaust/downpipe until you've settled on the turbo+manifold you want.

eurojulien

iTrader: (1)

Our cars area almost twins <3 (mine had 6ul on before). BTW that picture is not an OE MSM DP, that's a FM DP. Thanks for the heads up with CT and their tune. The car has had their tune for 4? years now, so I guess i'll up the injectors and leave it at that.