XFI vs ECM

[norbs]

Thanks
Can it self learn to the point of making a street friendly good gas mileage daily driver?

I dont see why not,  you can put any AF ratio  in and timing for cruising speed.  Self learn does not come in effect for cranking fuel, accel enrichment, or afterstart, you are on your own for those.

[norbs]

ANd i forgot to mention traction control , so you don;t have to worry about wiping the car out at top end.....becasu e the spinning is controlled, not violent.

[Top Speed]

Turbo tweak chip with Razor's Alky is a no brainer for a street car. 

[ttipe]

An external engine management system (Fast,BS3) is much better than running the stock abbaccus,even with all the add ons.Think of a 12" dia circle and points at every .5" distance around the circle.Now draw lines through every point tangent to the circle.This represents the control resolution of the stock computer.This also represents stock control resolution with respect to all six cylinders.Draw six circles just like the first and place points on all the circles .25" distance around each of the circles.The single circle represents "abbaccus control" using the stock computer (8 bit motorola 68000) for all 6 cylinder air/fuel control events.The 6 circles represent the air/fuel control events for six one cylinder engines operating in firing sequence from a Fast.This sequential individual control provides specific air fuel tables for each cylinder.Take the 6 circles and lay them all on top of each other and this illustrates the control resolution of the Fast compared to the stock computer.The Fast is much quicker than the stock computer.Just the fact that individual,sequential, greater resolution air fuel tables can be managed can keep a car further away from catastrophic destruction via detonation if crazy notions are avoided.Other benefits result from a fast once you get going with it.An external engine management system is expensive,but engine rebuilds are much more expensive.         

[norbs]

Actually you could use the XFI as a safety with alky, and a pressure switch, so that the AF ratio will only be modified when the alky is present,,,,,,,,,,,,top that one top speed

[daveismissing]

Norbs - Give us the pros and cons, when and why to switch, total cost, driveability.

The stock ecu does not provide immunity to interference from MSD boxes.

Thanks for getting engaged here Norbs, its all interesting and I'll have to study it all.


Did this (the above) turn out to be the ECM or all that Moates stuff?

[ttipe]

Forgot to mention there are a few gutsy/crazy racers running stock short blocks (no forged crank,no caps,no girdle) and surviving in competition with external engine management systems.Contro l of firing parameters saves engines (asside from fatique).

[ULYCYC]

An external engine management system (Fast,BS3) is much better than running the stock abbaccus,even with all the add ons.Think of a 12" dia circle and points at every .5" distance around the circle.Now draw lines through every point tangent to the circle.This represents the control resolution of the stock computer.This also represents stock control resolution with respect to all six cylinders.Draw six circles just like the first and place points on all the circles .25" distance around each of the circles.The single circle represents "abbaccus control" using the stock computer (8 bit motorola 68000) for all 6 cylinder air/fuel control events.The 6 circles represent the air/fuel control events for six one cylinder engines operating in firing sequence from a Fast.This sequential individual control provides specific air fuel tables for each cylinder.Take the 6 circles and lay them all on top of each other and this illustrates the control resolution of the Fast compared to the stock computer.The Fast is much quicker than the stock computer.Just the fact that individual,sequential, greater resolution air fuel tables can be managed can keep a car further away from catastrophic destruction via detonation if crazy notions are avoided.Other benefits result from a fast once you get going with it.An external engine management system is expensive,but engine rebuilds are much more expensive.         

So with a XFI you would put Tom Champion out of business and all the engine builders too..  Just kidding. Point is I've seen just as many if not more blown up Buicks and or melted heads with aftermarket units.  I don't blame the electronics, it's the end users lack of knowledge who thinks it's will save him motors and money in the long run.  You need to know how to tune or hire someone who can.  Seems like XFI, Bigstuff, Motec and others need to hire pros like Cal Hartline, Billy Anderson, Dale Cherry, Jack Cotton and  few others to get all the benefits out of a system that the average Joe can't or won't learn how too. I've seen them pop a few over the years also.

[ULYCYC]

Forgot to mention there are a few gutsy/crazy racers running stock short blocks (no forged crank,no caps,no girdle) and surviving in competition with external engine management systems.Contro l of firing parameters saves engines (asside from fatique).

Plenty in the 10's on a chip too.  A good tune without detonation is more important with either a chip or fast.

[Steve Wood]

In theory, one cannot argue.  In reality, there are plenty of actual examples that the extra resolution cannot be measured. 

[gbsean]

with any external ECM management there is a huge learning curve. with the Trans Pro which is a piggy back system it took months going back and forth with bob to get a basic setup. Each car with different combinations of inj...turbo..c onvertor etc takes time to set up... just t get a base driving tune...the to get WOT is another issue...if I had not cracked the block with my base tune @ 11.599 @ 119.91 with a crappy 1.834 60' with a lifted head the car should have been well into the 10's...again its all in the tune

[ttipe]

This has been a great thread.This discussion could go round and round for a long time.If I could just suggest that an external management system does provide more control if the user learns how to use it.The tune is the essence of everything that goes on regardless of the system being used.Another factor is that the stock electronic spark control system is not adequate for the power levels that are being produced.We can't hear the onset of knock while making 500 rwhp and it happens so fast.The stock esc system algorithm is not able to separate early inaudible knock from background noise,nor is it fast enough to cope at higher power levels.There is a system available to deal with inaudible knock,but its not cheap.Engine rebuilds are about 3 to 4 times as expensive.   

[Steve Wood]

Ah, someone that agrees with my pet peeve....how many times have people insisted they don't need to monitor detonation/timing retard because they don't hear any?  About three times a month, I would guess.    Given the cylinder pressures that a forced aspiration car incurs, detonation, when it occurs, is far more damaging than on a normally aspirated engine...and given the pressures, it occurs virtually instantaneousl y.


Still, on a street car, aftermarket management systems will seldom provide improved performance, cost more to have tuned, and probably will not make it past a comprehensive emissions test.

On the track, there are some features that are really nice, but, those might provide more safety if the tune is conservative.  On the other hand, Walt Judy has demonstrated that the factory ecm can be competitive with cars in TSM, and several others have gone faster than 8.5 in older classes.  In the hands of an experienced tuner, changes can certainly be made faster without having to burn a new chip.

Given the number of blown engines that have comes from aftermarket systems, I suspect all the great features in the world cannot trump a tuner that has greater ambitions than his platform can cash in.

As I stated previously, outside of the launch, tuning a race car is more simple than an all purpose street car, imo .  When you get a hyperactive mind like Norb's, there is no system that will ever be complex enuf to fit his needs

On a side note, I always wanted to try the Safeguard system to see how it worked. 

[ttipe]

I'm in the process of getting a JS Safeguard (Vampire).

[norbs]

Norbs - Give us the pros and cons, when and why to switch, total cost, driveability.

The stock ecu does not provide immunity to interference from MSD boxes.

Thanks for getting engaged here Norbs, its all interesting and I'll have to study it all.


Did this (the above) turn out to be the ECM or all that Moates stuff?

Dave, the Moates stuff would corrupt the bin file randomly after powering the ecu down. You could re-flash it and it would be fine for a day, a week,,,,,, then all of a sudden a ecu code pops up bad eeprom.  So i had to scrap that plan.  Using the chip from Eric it  ran great, however at high rpm/boost the mass air signal and during accel would go erratic, and start throwing timing all over the place, knock etc. Then I decided to go SD mode to eliminate the MAF out of the equation, it worked much better, however it still  would start doing weird things and I could not get consistant results to hold the timing or the closed loop fuel control steady at WOT.  Put the fast in and timing was rock solid, and great fuel control....... .......