thats why i did the group buy for the bolt on 36-1 trigger wheels. once the order comes in and i get them all shipped, i may do another one. it greatly simplifies the ms2. and ill be installing a ms2 on my 7mgte as well wit ha 4 bar map. hehehe
MegaSquirt II Successfully Running on 7M-GTE!!! (Lots of pics and walkthrough)
- Thread starter 87_7MGTE
- Start date
Doward said:
yep
as it does the dwell calculations also and in a inductance based system that is what makes or breaks the ignition.
ok, i have a tuning question, what sort of timing curve is everyone running? i know how to tune the fuel, i have a wideband for that, but i dont have a clue as to what to set the base map at. im guessing 10deg should be fine to start it, but whats the max advance i should run and at what rpm's, bost level etc.... i am installing a gt4082 with 0.68 a/r turbine, 2 walbro pumps, 830cc/min injectors, ms2 with 4 bar map and edis6 ignition. also will have a direct port water injection hooked up as well for higher boost. i plan on ~20psi fuel only and 26-30psi with the water injection. i just dont wantto tune by ear cause by the time i heatr the detonation it may be too late.
ok, i have another group buy going for the trigger wheels.
http://www.celicasupra.com/forums/showthread.php?t=29732
ill track it on that thread as well.
http://www.celicasupra.com/forums/showthread.php?t=29732
ill track it on that thread as well.
williamb82 said:
sorry
no one in thier right mind will answer this question... reason is. No two engines are ever the same. Only way to get it right, get it on a dyno. Period, end of discussion.
No otherway around it unfortunatly. gt4082 with a .68 a/r? That is a tiny A/R for that big a turbo???
Every factory 7mgte ecu has the same timing curve. Alot of people make alot of hp with there mystery timing map. Up to boost, they should all be about the same. Into boost, if the compression ratio is the same timing should be engine to engine. Not many people even run larger cams. Yes one engine might be able to run a degree or two more than another before deto if they are on the edge but I doubt you will fine much varyiation in timing under boost above 15 psi for most people, even 2jz guys.
figgie said:
i plan to tune it on the dyno, thing is, i need to make sure i dont set it to far up to begine with or set it so low that it takes 3 hrs of runs to get it to where it should be. i figure this will give me an idea of where to set the baseline(ill go lower then what the max recomended is to be safe and slowly add it in till its right).
Clifton said:
stock ecu does come from factory with the same curve for ALL 7m but guess what the stock 7m ecu does... LEARN. It adapts. The timing maps are FAR from stock since the last time the ecu was reset, sooooo many variables, sorry chief, it don't work that way.
In reality you want to put whatever timing in your ecu, by all means go for it. Plenty of people that have in fact posted thier timing in the aemboard. Grab one of those and run with it.
figgie said:
why is that tiny? im only going to run 93 octane, no race gas. and no nitrous, and will be using a 50mm wastegate, 4in dp and exhaust, 2in pipe from the wastegate integrated back to the dp, etc.. ill have plenty of flow. id rather have the quick spool and broad power band then the extra 30-50 hp from the larger turbine housing on the top end with lag. also, turbo isnt that big, has a 58mm inducer and 82mm exducer. i figure ~500rwhp on pump gas, more with water injection
Will, does the system have a knock sens?
I have always started with a curve that peaks at 30deg @ 3000rpm and flatlines from there to redline in the Atmo map range (100kPa) and then pull 1deg per psi untill you get to 20deg total timing at which point stop. You should never have to run less then 20deg of total timing. if you have to pull it down to below 20 to surpress detonation then you either are to lean (probably not), need higher octane, lower boost or lower compression.
Thats the base timing curve that I have always used for every engine and as always been relitively close.
I am assuming that once you have the base line that you know how to tune the curve form there for the particular engine at hand.
I have always started with a curve that peaks at 30deg @ 3000rpm and flatlines from there to redline in the Atmo map range (100kPa) and then pull 1deg per psi untill you get to 20deg total timing at which point stop. You should never have to run less then 20deg of total timing. if you have to pull it down to below 20 to surpress detonation then you either are to lean (probably not), need higher octane, lower boost or lower compression.
Thats the base timing curve that I have always used for every engine and as always been relitively close.
I am assuming that once you have the base line that you know how to tune the curve form there for the particular engine at hand.
williamb82 said:
as with everything else it is comprimises
a turbo is peaky. the nature of the beast. A smaller A/R won't make the power band broader. It will just move the peak down in rpm range. Problem is with a bigger turbo of the gt40 size on up. Having a smaller a/r will move the surge line to the right instead of the left. I can see a .64 A/R on a 35r but on a 40? i would no way go lower than a .8 a/r. But that is me since I detest comp surge.
i have an antisurge compressor housing and its a t4 turbine housing, should still be fine. this is a street car i literally intend to drive every day. this turbo will hold boost till readline and prolly further, so i dont see the problem. also, ill be running a 50mm wastegate, that should flow quite a bit as well. all the exhaust gas doesnt have to go through the turbine, just whats needed to provde the boost pressure i want the egine to get. ive seen a big single on a mkiv wit ha small a/r turbine, guy ran 2 35mm wastegates. worked great.
figgie said:
Chief, it does work that way. Yes it can learn. It can correct fuel at closed loop. Don't think so on timing. Ya, it may pull some during an knock event but it's not obdII like later mkiv's. I have yet to even see a post on what the factory timing is under boost. If you know something about the 7m ecu please share it with everyone. There were many turbo and n/a cars that are older than MKIII's. Guess what. Most can pull some timing with the knock sensor but that's it. I've had first hand experience with 3 (1 Toyota) that don't not change timing from one knock event to the next.
williamb82
I sent you my msq a while ago, I can send you a screen shot of my timing and a datalog if you want.
figgie said:
FYI, A gt35R and the GT40 in question (GT40-82) have very similar compressor wheel and turbine wheel sizes.
The 35R has a few mm larger inducer, same size exducer for the compressor wheel and the 35R has a 9mm smaller turbine wheel.
The 3582R is rated for more power than the GT40 as well.
yeah clifton, thatd be awesome. i ned to search my email for that attachment. dont have the car done so hadnt bothered. guess i should as i have 780cc/min injectors and iirc you said you had 700cc.
I'll send you a newer one. My fuel was higher than it should have been. My pump was a lttile more than maxed and I was making up for ther dropping pressure. The old one will work, it would just be rich up top. I have since added twin pumps so pressure is were it should be. I'll send it tonight.
Clifton said:
you never ever will see that information unless someone that posts on these boards has rev engineered the TCCM. Jetjock is the closest that I know off but I highly doubt he has been able to do direct read of the ign table in the stock ECM (ala techtom, g-force).
AIT, AFM, CLT all affect the fuel AND timing map. Always has. That is the reason why timing is diff while engine is cold then when it is not
The knock sensor is an after-"failsafe" (and I use the "failsafe" term REAL loosely)
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blackout_89t said:
wait the gt40 is not R?
nm then. dunno why i was reading GT40R when that was never posted.