5.7 Hemi Racers

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Div6

Div6

5.7HemiDuster
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Nov 10, 2008
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I have a stock 2004 5.7 Hemi "TTI headers" from a RAM 1500 in my 72 Duster I use for bracket racing. Over the years I have had some success racing a carb car and was conned into EFI Hemi. This was a complete transplant, new wire harness, ECM fly by wire pedal, etc. The problem I have is the car is not consistent. Does anybody out there know what can be tweeked or modified to get this thing to run the number or within +/- .02? I have been bracket racing for a long time and regret going the EFI way but am committed $$$ having spent the time and money. If you suggest a Diablo Trinity, what parameters would be worth tweeking? Not used to going out in round 2.

Thanks
 
Is the car consistent during time runs and the first round then second round you get the where the h@## did that number come from routine?

-Eric-
 
Where is your IAT sensor located?
When I was racing my 6.1 Magnum it was very inconsistent until I moved my IAT away from the engine. The sensor is affected by the rising heat off of your block. It's very hard to get to the line with the same amount of cool down and idling time.
 
The factory PCM was never designed with bracket racing in mind so holding you to .02 might be impossible. You might try posting this question over on one of the lx forums where some bracket race late model hemis.

According to this thread temperature control is a key to consistency, this makes sense since in fuel injection the computer uses air and water temp as part of the inputs in determining ignition timing and fuel load. Thus if your temp is all over the map your HP will change significantly enough to effect your et.

http://www.lxforums.com/board/f86/bracket-racing-tips-techniques-229081/

http://www.lxforums.com/board/f252/thoughts-bracket-racing-228821/

Here's a thread about diablo tuners that claims the eliminate some bog off idle while drag racing. This elimination of the bog might help with consistency. They seem to like the 91 Octane tune. Another aspect of the diablo tuners is that they can increase the rate at which the computer opens the throttle. Thus, when you mash the throttle it will more rapidly go to full throttle, this might also increase consistency. Here's a thread discussing the bog.

http://www.chargerforumz.com/showthread.php?t=135719

Finally if uber consistency is required a fully programable fuel injection ECM might be in your future. FAST, AEM, Bigstuff, or Megasquirt all offer fuel injection ECMs that replace the drive by wire with cable operated throttle body.

Best of Luck,

If that is your Duster in your pic, nice car.

Regards,

Joe Dokes
 
Sledgehammer said:
Is the car consistent during time runs and the first round then second round you get the where the h@## did that number come from routine?

-Eric-
Click to expand...

You understand exactley what is going on.
​
 
SlimPikins said:
Where is your IAT sensor located?
When I was racing my 6.1 Magnum it was very inconsistent until I moved my IAT away from the engine. The sensor is affected by the rising heat off of your block. It's very hard to get to the line with the same amount of cool down and idling time.
Click to expand...

The sensor is in the front of the airbox Time to relocate Thanks
 
Div6 said:
The sensor is in the front of the airbox Time to relocate Thanks
Click to expand...

I don't think I have a picture, but I had a AFE Stage 2 CAI on mine. The cone had a soft rubber end on it. I drilled a hole in the end of the cone filter and installed the sensor there, right where it drew the air in. Seemed to work great. Hope it works for you.
 
Div6 said:
You understand exactley what is going on.
​
Click to expand...
I had that problem with a 2.2L I was bracket racing years ago and found out the system was learning and making adjustments that would be all over the place. Start looking at where your sensors are located like what was suggested above.
 
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