R
ri87T
Guest
How much does it cost to get the ecm modified to handle bigger injectors?
TurboBob charges 125.00
(including return shipping by FedEx Economy for prepaid orders)
The modification is done using the correct 2.5 amp Peak and Hold drivers,
the correct power supply modifications (no battery drain issues here),
and the correct supression components.
Cleaning of the connector for Direct Scan at no charge upon request.
This is done using the correct chemical agent so no excessive scraping
of the contacts is required, all the coating is removed and the contact
fingers are polished. The case is modified to allow access to the connector.
Thanks
TurboBob
(including return shipping by FedEx Economy for prepaid orders)
The modification is done using the correct 2.5 amp Peak and Hold drivers,
the correct power supply modifications (no battery drain issues here),
and the correct supression components.
Cleaning of the connector for Direct Scan at no charge upon request.
This is done using the correct chemical agent so no excessive scraping
of the contacts is required, all the coating is removed and the contact
fingers are polished. The case is modified to allow access to the connector.
Thanks
TurboBob
R
ri87T
Guest
thanks for the info - don't think I'll be doing this soon as I don't know what I want to do with this car!!! But that's a whole other topic....
The change is necessary when you switch to low impedance (resistance)
injectors, typically 55's and larger. These low impedance injectors require a
peak-and-hold driver to operate correctly. 2 to 3 ohm injectors (all the ones we use)
require a 2.5 amp driver.
Then, of course, you need a chip programmed for the big injectors.
TurboBob
injectors, typically 55's and larger. These low impedance injectors require a
peak-and-hold driver to operate correctly. 2 to 3 ohm injectors (all the ones we use)
require a 2.5 amp driver.
Then, of course, you need a chip programmed for the big injectors.
TurboBob
BLACK6PACK
1 sec reaction King
- Joined
- May 24, 2001
RI87T,
If I were you I'd slap a 44 or 49 turbo and injectors on there. You could probably get the whole setup used for around $500. That would be between 1/2 and 3/4 of a second improvement.
If I were you I'd slap a 44 or 49 turbo and injectors on there. You could probably get the whole setup used for around $500. That would be between 1/2 and 3/4 of a second improvement.
R
ri87T
Guest
Black6Pack,
I'm thinking of either getting a 44 and 50#MSDs, or going for an innovative 66dbb with injectors that match well with that turbo(72#s??). I just don't know how streetable the latter setup would be. I'm leaning towards the 44 right now.
BTW, I plan on rebuilding the motor, and p&p everything at some point, just not sure when I can afford it.
I'm thinking of either getting a 44 and 50#MSDs, or going for an innovative 66dbb with injectors that match well with that turbo(72#s??). I just don't know how streetable the latter setup would be. I'm leaning towards the 44 right now.
BTW, I plan on rebuilding the motor, and p&p everything at some point, just not sure when I can afford it.
There is a huge arsed difference from, it runs, to it runs correctly.
If your settling for it runs, well then nothing really matters.
Using the P+Hs generates less heat for the injector drivers to deal with. ALSO, by having the correct drivers in there, the maintain voltage/current is less, and that speeds up the injector's closing time. Having the injector turn ON, and OFF correctly is a good thing.
Carl James, also runs his ecm with the oem injectors, and I have tons of repsect for him, BUT he also has enough talent to get the calibration right after making said non-changes.
Personally, I think GM and the billions it spends on ecms, need to be given credit where credit is do. ie, in some respects your not going to redesign anything better then what they did with the constraints they have to deal with.
Once you start getting into the heavy class, if you want things right, it takes some money to do. Again in MO, 50s are popular just because they say a few bucks on getting the ecm modified. Being saturated, they also probably can be gotten to work rather well by some tuners, since you don't need to redo the battery voltage correction stuff (which accounts for opening and closing characteristics). But, again some clever guys cover that with other corrections, so you never really see what they've done anyway.
I've got 2 years and lots of long trips on my Bailey modifed ecm, using 55s I have a smoother idle then ever, and have broken 30 MPG. And with a 60 turbo, and running 23 PSI on pump gas, I'll leave the performance to your imagination....
There is also a matter of suggested operating times, for the P+Hs, vs Saturated, when you get to the 50s your pushing the limits on the design characterists of the injector it's self. Again the 55s win.
There's alot of myths still hanging around....
Yep, 94 Octane.
Tuning tuning, and tuning.
The only trick is I did some grinding in the combustion chambers to remove any sharpe edges.
Well I did relocate the MAF, and am using a Translator plus.
The biggest aid in tuning was using a Wide Band. Details of it are at WWW.DIY-WB.COM
Once you realise the stock one is like reading tea leaves, you can get unstuck and go fast. Given enough passes or luck you can get the AFR right, but with the WB you know where you are.
boostcreep
New Member
- Joined
- Nov 30, 2001
I could have sworn I read that the P&H's generated a lot of heat in the driver. Could you please explain ?
(This is for Bruce in case the quote thingy doesn't work)Nick
you guys will have to double check my math.
Stock ECM, stock injectors
12volts, 12 ohm, Darlington transistors(1.2Vce)
ECM 1.08 watts per 'channel' .9 amp per channel,
7.2 watts total in the ECM, 12 amps flowing in the ground pin at 100% dutycycle
Injectors dissipate 10.8 watts each at 100% DC
P&H 2.5 amp
12 volts 3 ohm (impedance goes up with temp.)
ECM .5a hold current drops 1.5 volts in the injector leaving 10.5 in the ECM
10.5 volts at .5 amp per channel in the ECM is 5.5 watts per channel in the ECM
33 watts total in the ECM
.5 amp per channel 3 amps total flowing in the ground pin
Injectors dissipate .75 watts each at 100% dutycycle
Low impedance injectors with stock ECM
12 volts, 3 ohm
ECM 5.25 watts per channel 3.5 amps per channel
31.5 watts total in the ECM
21 amps flowing in the ground pin.
Injectors dissipate 36.75 watts each
This assumes the stock ECM driver transistors are up to the task.
It might work but you are punishing the injectors. The car will run a
lot richer at idle too.
Bob
Stock ECM, stock injectors
12volts, 12 ohm, Darlington transistors(1.2Vce)
ECM 1.08 watts per 'channel' .9 amp per channel,
7.2 watts total in the ECM, 12 amps flowing in the ground pin at 100% dutycycle
Injectors dissipate 10.8 watts each at 100% DC
P&H 2.5 amp
12 volts 3 ohm (impedance goes up with temp.)
ECM .5a hold current drops 1.5 volts in the injector leaving 10.5 in the ECM
10.5 volts at .5 amp per channel in the ECM is 5.5 watts per channel in the ECM
33 watts total in the ECM
.5 amp per channel 3 amps total flowing in the ground pin
Injectors dissipate .75 watts each at 100% dutycycle
Low impedance injectors with stock ECM
12 volts, 3 ohm
ECM 5.25 watts per channel 3.5 amps per channel
31.5 watts total in the ECM
21 amps flowing in the ground pin.
Injectors dissipate 36.75 watts each
This assumes the stock ECM driver transistors are up to the task.
It might work but you are punishing the injectors. The car will run a
lot richer at idle too.
Bob
ri87t , your welcome to meet me sometime and i'll take you for a ride in each car. the small turbo car is a blast around town and is 11 sec capable, the other car is more for the strip, ie some lag time and slightly diminshed gas mileage. its just not as much fun to drive around, but it lays waste up top.
Not sure what Ruce was trying to say here since anyone can run the ecm with the oem injectors
. I do use saturated drivers (not Darlingtons and not the stock drivers) with low impedance 72's - it was quick and cheap and I wanted to see how well it would work before bothering to put in the peak and holds. Worked well enough that I never bothered to go on. The idle pulse width is about 2 msec which is right at the minimum for this setup so sometimes it is a little rich and sometimes the blm will wander up and down as the ecm gets different amounts of fuel than it expected as the delivery reproducibility isn't perfect. That said, you can see this on direct scan but if you didn't look at that you would never know by the way the engine runs and drives. I even fast passed the Maryland IM240 dyno smog test .I'll take a pass at it - hope you don't mind.
I think you are a little off here. With 12 volts on the supply and 1.2 Vce in the transistor you have 12-1.2=10.8 volts across the 12 ohm injector (at infinite time so the inductive transient has damped out); 10.8V/12 ohm = 0.9 amps per channel. Yes, 0.9 amps * 1.2 Vce gives 1.08 watts per channel in the ecm but wouldn't the total power in the ecm be 6 * 1.08 W = 6.5 W, not 7.2 W, and the total current on the ground pin at 100 % DC be 6 * 0.9 = 5.4 A, not 12 amps?
And here, 10.5 volts dropped across the peak-n-hold driver * 0.5 A gives 5.25 W per driver, * 6 gives 31.5 W total in the ecm
Using the 1.2 Vce as above, 12-1.2=10.8V across injector, /3 ohms = 3.6 A per channel, * 1.2 V = 4.32 W per channel in ecm, * 6 gives 21.6 amps and 25.9 W total in ecm. The saturated drivers dissipate less power in the ecm than the peak and holds. However, 10.8 V * 3.6 A = 38.9 W dissipated in each injector - don't run them dry. Actually, in my case Vcesat is more like 0.6 V so the total power dissipated in the ecm is 13.7 W.
I've heard of one person getting away with using the stock drivers with low impedance injectors, but I've heard of several people who let out various quantities of magic smoke trying this. I didn't even consider it for myself. As for the total current, I've done this math several times, and I know the fp/inj fuse is 15 or 20 A, not 30 A, but I've never heard of anyone blowing this fuse using saturated drivers and low impedance injectors. Oh, of coure all these power estimates are a little low if the alternator is up to snuff, since we should have used 13.5-14 V instead of 12 for the supply voltage.
