Aftermarket Issues with 5.7L Hemi

Discussion of the 5.7L-6.1L-6.4L HEMIs.

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scottm
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Aftermarket Issues with 5.7L Hemi

Post by scottm » Fri Feb 07, 2003 10:47 am

I have received a forwarded message from JBA
that they will not be releasing their headers for
the 5.7L Hemi for several months. The issue at
hand, they mention, is the computer limiting the
power output of the engine.

I also noticed that the Kenne-Bell supercharger
for the 5.7L Hemi is also delayed due to issues
with calibration. They estimate 6 more months.

Does anyone know what their problems are?
Any chance that they have similar problems?
Any ideas on what it will take to resolve them?
Scott Moseman
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Evilbert1972
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Post by Evilbert1972 » Mon Feb 17, 2003 2:38 pm

i was talking to one of my pals that works for a chysler delar ship and he said the not only dose the computer limit power it will not alow you to burn out o any thing like that. and i dont think te after market or chysler has yet co come out whith a prom to remady this problem.

kbuicker
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Post by kbuicker » Mon Feb 24, 2003 10:27 pm

Evilbert1972 wrote:i was talking to one of my pals that works for a chysler delar ship and he said the not only dose the computer limit power it will not alow you to burn out o any thing like that. and i dont think te after market or chysler has yet co come out whith a prom to remady this problem.
Really? I just impressed my boss with a nice little burnout the other day, had to hold the brakes a tad, but it did burn out without issues.

As far as stomping to burn out, I have not tried yet.
Kevin

Evilbert1972
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Post by Evilbert1972 » Tue Feb 25, 2003 11:40 pm

ya its because of the tracshon controle system
and it limits a lot of power to the rear wheels

426 dreamer
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Post by 426 dreamer » Tue Apr 22, 2003 10:58 am

Mine did a nice lil burn out by stomping and dry pavement.

tirpitz

Post by tirpitz » Mon May 19, 2003 9:33 pm

I also got a good burnout on dry road by stomping the gas. 2 nice patches 10 ft long left behind.

fast5800pdhemi
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Post by fast5800pdhemi » Mon Jan 12, 2004 6:01 pm

yeah i have gone through two sets of tires already and one ticket from my truck sometimes its hard to keep it from doing a little bit of burning

Astral
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Post by Astral » Fri Jan 16, 2004 3:41 am

Superchips is working on a Hemi donated by Atlantic over at DTW with promising results that is possibly leading to an early delivery of a tuner for spring. Just remember, these things take time. But keep your eyes open.

Astral

crash
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Post by crash » Fri Jan 16, 2004 10:44 am

can't we just trick the computer so the speed limiter gets tuurned off?

i mean it just a computer how smart can it be?


ahhhhhhhh no noooo stay back!
ahhhhhhhhhh .....

crash dosn't mean that he is a good human and computers are his freind!

Headgames
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Speed Density

Post by Headgames » Wed Feb 18, 2004 2:13 am

The problem with the new Hemi is that the engine controller uses Speed/Density to control air and fuel and spark timing. Any changes in airflow (in or out) are basically ignored, and can actually reduce performance. The advantages of Speed/Density are better consistency in a variety of conditions, but it does limit the potential of aftermarket add-ons. Chevy uses a Mass Airflow system to control the fuel injection and spark. This is a more flexible system, but it does trade consistency and finite control.

The reason I've heard for the choice of a Speed/Density system over Mass Airflow was emissions related. The finer control afforded by Speed/Density made it the better choice for the already emissions challenged Hemi.

Oh, and a side note while I'm at it: The name Hemi may come from the original design's hemispherical combustion chambers, but from the start it was discovered that the real advantage in the design was in port layout and valve geometry, not the combustion chamber shape. In fact it was discovered that volumetric efficiency increased with ever smaller spherical segments. Even the early hemi's got by with substantially less than a full hemisphere for a combustion chamber. The new Hemi is every bit as much a "Hemi" as any other engine bearing that name. The "Semi-Hemi" engines, like the polyspheres and the Ford Boss 429, had offset valves and less than ideal port configurations, despite the other similarities in their designs.

KingoftheHill
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Post by KingoftheHill » Wed Feb 18, 2004 4:23 am

Headgames, How interesting this issue was also stated by DMC engineering staff during the interview with Hotrodding's reporter.What you may know know though is that Speed&Performance and Squier Inc are in the process of a reprogaming of the ECU to except the increased signal that the speed density sensor is reading. 8)
2004 SLT Quad Cab,2x2,Hemi,3.92 ratio,CST 4"Lift,Ultra 17 inch Eagles,33x12.50/17 BajaClaw Radials,Bushwacker OE Fenderflares Bushwacker bedrails.

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Post by scottm » Wed Feb 18, 2004 8:45 am

I'm not an automotive engineer, but would developing an
aftermarket mass air setup be out of the question? Or is
it not worth the development and manufacturing costs? I
imagine it requires new sensors, ECU and so forth, so not
worth the R&D unless the factory does it for production.

Would a Speed Density reprogrammer be an easy tool to
use for shadetree mechanics? Would it have preset modes
you pick from? Or do you have to be even more technical?
Scott Moseman
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Headgames
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Speed Density vs. Mass Air

Post by Headgames » Wed Feb 18, 2004 6:37 pm

Okay, I admit I'm not an engineer either, so I can't really speak with any authority on the relative merits of either engine management system. From what I've read, you can change from speed/density to mass airflow with a new ECU and the proper feedback sensors, but with modern computers controlling so much more than just air and fuel, that's not really cost effective.

All I've been able to find so far is that the speed/density computer would need to be adjusted (and therefore adjustABLE) for each change to the intake/exhaust. Basically you'd be remapping the fuel and spark timing to match the new combination. This would probably require at least a dyno tuning session and the proper reprogramming device to interface with the above mentioned adjustable ECU. I don't know if any of that is in place already, or even possible without factory sponsorship.

However, since a number of aftermarket companies have developed blowers and headers and such, perhaps the capability is there, but it may be too difficult to implement for an end user? If so, it will limit major upgrades to specialty shops. this might lead to more consistent performance from those upgrades, but it will certainly add to the bottom line.

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Post by scottm » Wed Feb 18, 2004 10:00 pm

Create a speed density re-programmer that can export
and import configs. We could build an online database
with these configs that someone could download which
ever tune best fits their setup. Download, import and go!

Sound crazy? Not really. The Mustang folks do just that.
From the input that I have received, it would be popular!
Scott Moseman
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