$600 for used FM Link ecu a good deal? - Page 2 - Miata Turbo Forum - Boost cars, acquire cats.

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DIY Turbo Discussion greddy on a 1.8? homebrew kit?

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Old 08-14-2007, 09:31 PM   #21
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The main problem with the Link is that it now gives very poor bang/buck compared to other ecus, especially MS. A 600 dollar link doesn't have that problem. That is an insanely good price.

From my experience the problems with the Link are mostly problems with stock components that the link doesn't replace.

Main shortcomings:
-retains stock fuel rail and stock coilpacks
-uses one byte for manifold pressure so >23 psi is out of the question
-ecu defaults are a bit limp-wristed IMO, but they work fine and you can easily tune for more power. Example: on the old motor/turbo, ecu defaults at 12 psi was worth 190whp on the stock fuel rail. Dyno said I was running 10.5:1 AFR. Removing a pile of fuel and adding 2 degrees of timing got me a 30whp bump over the next 2 runs.
-ecu is stretched to the limit many times over in terms of features. There is no way to control additional outlets or log additional inputs. Also, a lot of stuff that other ECUs let you fiddle with are stuck in the firmware instead of the user-modifiable memory. (dwell, per-cylinder ign trim, sequential igns, etc). Not being able to datalog EGT is annoying.

What year/version of Link is this? What year motor? The various ECUs differ slightly in terms of capability. There is MK1 (1.6), MK2 (1.8) and MK2 Obiwan (96-97). I have the obiwan.
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Old 08-14-2007, 09:40 PM   #22
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Beerslurpy,

Nice info. I've already got an AEM WB. Just not installed yet. I'll be dual feeding the stock rail. I have no aspirations to run 23psi on my stock motor so the limits shouldn't be a problem. I'd like to run a safe 11-12psi. Sounds like your 12psi tune for 220hp is just what I'm after. Looking for it to run hard and reliable. Don't want or need to push limits of the stock drivetrain. (except that weak little clutch I'm gonna have to replace.)
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Old 08-14-2007, 09:41 PM   #23
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And 99 percent of link shortcomings can be worked around or ignored:
-I am still not at the limit of the stock ecu in terms of MAP values. I've realistically got another 2-3 psi left before it runs out of room. You will not find this a serious limitation for some time.
-Replace stock fuel rail, get wideband, get COPs.
-Most other things you would want to trigger with the ECU can be triggered the old fashioned way like the hot rod guys have been doing for decades. Pressure and temperature based switches wired in serial with what you want turned on. The aftermarket supplies pretty much every need that isn't satisfied by a 600 dollar Link.
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Old 08-14-2007, 09:43 PM   #24
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Quote:
Originally Posted by cueball1 View Post
Beerslurpy,

Nice info. I've already got an AEM WB. Just not installed yet. I'll be dual feeding the stock rail. I have no aspirations to run 23psi on my stock motor so the limits shouldn't be a problem. I'd like to run a safe 11-12psi. Sounds like your 12psi tune for 220hp is just what I'm after. Looking for it to run hard and reliable. Don't want or need to push limits of the stock drivetrain. (except that weak little clutch I'm gonna have to replace.)
If you do the AEM WB and a vishnu rail, I would expect > 220whp easily.

I would have dynoed much higher but I had collosal puke and die past 5500 rpms. Max power was at 6000 rpms. My engine was on the verge of crankwalking at that time, so lubrication might have been part of the problem. The inefficient T04B probably didn't help much either with it's 50 percent compressor efficiency at redline.

I also had a problem with boost control because my WG was set at 3 psi and I wasn't able to ramp up the WG solenoid duty cycle enough to maintain full boost up to redline. I had ironed out these problems and was getting ready for another dyno and a track day when I crankwalked. Instead of dynoing again, I had to drive the OTM for a month while I had the engine rebuilt. I never got back to dyno again since then. I really need to find one.
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Old 08-14-2007, 10:23 PM   #25
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COP's really make that big of difference? I'm trying to keep this reasonable both in cost and complexity. I looked at a couple of threads about them but I'm not sure how significant the gains are on a stock block at the power levels I'm looking at. I'm not bagging on them, I really don't know how significant they are. If I can pick up hp at a given pressure or be able to run the same hp at a lower pressure I'll take a look at them. What're the advantages and gains?
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Old 08-15-2007, 12:36 AM   #26
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At higher RPM, the stock miata coils lose their ability to push enough spark. This shows up as minor knock sensor irritation that rapidly builds as RPM climbs. Jason C and others theorized that the engine starts leaving partially combusted crap in the cylinders each cycle. I can't find the datalog, but past around 6500-7000 rpm you see a parabolic upwards arc of knock increasing. Nothing catastrophic, but the engine is doing that instead of making power. It's only a little bit of power being lost at the upper end of the powerband, but I'd like to get rid of it and rest easy.

COPS arent a set in stone requirement, but I suspect they will help, especially if you are running suboptimal air/fuel mixtures.
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Old 08-15-2007, 05:37 AM   #27
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if you switch to a 3 or 4 bar MAP sensor, the link will handle it but u need to scale the rows accordingly. I asked Ray about this some time back...

EGT can be datalogged, but you can log only 1 ext input, so u can't do WB02 at the same time.

it's a fairly basic ecu don't forget, and priced accordingly

Quote:
Originally Posted by beerslurpy View Post
Main shortcomings:
...
-uses one byte for manifold pressure so >23 psi is out of the question
...etc). Not being able to datalog EGT is annoying.
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Old 08-15-2007, 05:58 AM   #28
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Oh crap you're right, the link is just scaling the byte to the voltage signal. Durrr. Do you know what MAP sensor it uses? GM?

Yeah I'm stupid for not thinking of that after all the work I did on my datalogger.

And yeah, I have wideband so EGT is not really high on my list of priorities. It's really just a sort of OH SHI- gauge now so I can spot something egregiously wrong.
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