c4boom

and that dream is to make the the fastest g10 equiped car i can. this is the 3 banger that comes in the geo metro and pontiac firefly. what i need is a fuel controle setup that will work with the motor it is a 993 cc motor and only has 3 cyl. is there a gm computer that can be used to run this thing. eventualy it will be turbod so that it can make aobut 150 hp this is very posibal and i know a few people that have done it but the motors do not last long due to the inability to tune them with the stock computer. so what are my options

Grumpy

At $160 a pop for headgaskets (turbo version), it's not a cheap engine to work on. Everything must have be diamond plated, or Ti.

If you just have too, then maybe using a 6 cylinder ecm variant would be an option. Just go thur and 1/2 all the min rpm related stuff.

Now there's a Metro shelled tube framed car, running a GN engine that runs 9s, that looks like alot of fun.

c4boom

we are thinking of o ringging the thing now how would it handle idle fueling with a 6 cyl ecm

c4boom

are there any ecms out there that can run a variable # of cylenders this little bugger is going to be our entry in the import drags and with only 1.0l we are hoping for 13's on motor and 12.5s on the gas.

dimented24x7

iTrader: (2)

A tbi ecm would, I think. It does the fueling on a per unit cylinder basis so its just a matter of entering the right # of cylinders thats needed to calculate the rpms and such. But, its not set up for boost or high revving applications. But then again none of the ecms are functional over about 6k since the rpms are limited to 6375 due to the fact that theyre 8 bit. doesnt stop working, just hangs at its max when you go over the limit.

Is there any reason a '730 or a '749 physically couldnt work with a 3 cyl? I imagine it would need some tweaking but I think it would work.

c4boom

i dont know if it would or wouldnt but i know the shift point on this thing is 8500 and that is due to the fact that i am afraid that it is going to lunch some thing it is still making good power and such and as for boost i am just going to use a fmu and tune it for wot part throtle is not realy a issue with this thing. when it was stock we would drive it on the high way by puting it in 5th and just hold it to the floor it would hold at about 70-80 but when you hit a hill you would have to down shift to 4th what a gutless pos

dimented24x7

iTrader: (2)

You might consider an aftermarket ECU if your going to be revving that high. The stock ecms arnt set up for such high rpm usage.

Grumpy

No?
The ecms will, but the code would need a lil work. Take the RPM/25 and make it 37.5 or 50, and you can double the effective range.

There's some GNs running big numbers (7,000 RPM, and 9 sec ETs with the *stock* ecm).

c4boom

i am on a budget on this thing so i have to keep it some what cheap i only paid 300 bucks for the car so if it gets cooked no huge loss.

plus i have 4 other motors for back ups i can make it work some way. now with a tbi computer what would be a good tbi to start with i need some thing that will be able to suport the motor in the 150 HP range i dont care if i have to run 1 or 2 injectors i can make a adapter some how or i can weld up a intake if all else fails. What about a computer out of a 2.5 iron duke or some thing.

dimented24x7

iTrader: (2)

Wasnt quite sure he was ready to take the source coding plunge yet and if money was a true issue.

c4boom, if you wish you can change how the RPM is calculated. Youll loose some resolution but that may not matter if your only really concerned with jsut racing the thing. This will require that you change a double byte value used in calculating the rpm from the DRP and tweak the other calculated rpm values as well so theyre still correct. Youll also have to go through the calibration and the tables that will be using the newly calculated value and change them so that the rpm change is taken into account.

You could jsut leave it as-is but if your gonna buzz the motor real good you wont have any control past around 6000 rpm.

dimented24x7

iTrader: (2)

You could use a monobarrel with an 80 somethign pph injector/ mpfi and a 7730 ecm with the right calibration or a standard two barrel tbi off of a L03 or something and ecm. Both would work. The tbi ecm will need alot more tweaking but the documentation is better. The tpi ecm is definatly the better of the two hardware wise, though.

JPrevost

Has anybody used a GM ecm to control an engine that revs to 14000? If so I think I might just try it. If it works that would save our FSAE team over $600 and probably give us 1st place in the cost competition . That would be awesome to get a Honda motorcycle engine running off of a GM ecm from the 80's, lol.

dimented24x7

iTrader: (2)

Probably would work fine with the right changes. All in all it would need some overhauling to work properly but it certainly could be done and would be neat. Once youd have the source code worked out you could do whatever you wanted with it.

c4boom

i think source code is a bit our of my reach right now. i am still grasping tuning my 747 in my truck getting there though. my problem is understanding how every thing works together. and what each table and constant dose. i wish there was a class or even some one around me that had a good grasp on this stuff so they could help me understand it a bit better. i wish i could just slap a carb on this thing but then boosting it would be a issue. well i think i am going to have to do alot more reading so that i will be able to efectively get this thing to run. man am i dumb compaird to some of you guys

Grumpy

It all takes time, there's just no easy way around trying to learn something this complex.
Some of the folks here have been doing this stuff for about a decade, and they all went thur the head pounding involved. Not to mention years ago, alot less was known, and it was all the more frustrating trying to even figure this stuff out. If you think it's tough now, in the early days, *we* made one location changes at a time in the .bin file, and then spent time on the ecm bench trying to figure out what entry changed what parameter.

c4boom

all i would realy like to do is get this thing to run ok in light to mid throttle and real good at wot up to 7500 rpms or so. I dont care how hacked it is. Would there be a way to run it off a maf setup out of a v6 or some thing. There is no way in hell this thing will make over 170-180 hp without turning into shrapnal so the isnt that big of a demand on the air intake To bad there isnt just a bit that could be changed in the 165 to tell the motor that there are only 3 cyl. The stock ecm dose not even have a eprome in it. I think it is all coded into the proscesor or some thing. who knows may be ill try some thing weird i just have to find out what.