I wanted to point out a number of things brought up in this thread, with the end result showing why you most likely do not want any part of buying or installing a Haltech (or any other aftermarket) ecu. I’ve spoken with Dave at DDM and Rabtech about this at length today.
First, let’s look at a few dyno charts from 3 widely varying sources:
Suzuki Hayabusa turbo motorcycle:
http://www.powerhousemc.com/chart3.gif
Well built LS V8 dyno chart:
http://www.camaro5.com/forums/…357018&stc=1&d=1334158810
Tesla dyno charts:
http://www.dragtimes.com/blog/…v3-power-output-graph.jpg
http://teslaforum.dk/ow_userfi…s/base/981-Tesla_Dyno.png
All 3 of these vehicles types would be considered very quick. The Hayabusa turbo would take a very skilled rider to extract maximum performance out of it. The Tesla, your blind grandmother could look like a hero at the drag strip with. The point here is you ideally want a very broad flat torque curve across a large RPM range for a usable and responsive performance vehicle. The LS V8 dyno chart from above shows a near ideal curve for a gasoline powered engine.
Now let’s look specifically at Rabtech’s posted dyno charts from his Slingshot.
From the “I knew it was strong. But not 510hp strong” thread:
http://uploads.tapatalk-cdn.co…192a801e8b3a6b8a05c09.jpg
and the latest dyno charts:
https://uploads.tapatalk-cdn.c…37f30f32bb863e9d28fe6.jpg
https://uploads.tapatalk-cdn.c…05660446454992ed591e1.jpg
What’s shown in the first dyno chart is a pretty much a stock Hahn turbo setup with the boost turned up, and in the second a highly customized turbo setup by Dave at DDM works. Hardware is quite different, but HP and torque numbers are very close, considering this was run on the same dyno. Weather and temperature conditions favored the most recent pulls quite a bit. The point here is the area under the torque curve is quite a bit higher in the first chart in the range where you would feel it in normal driving.
It should be pointed out that Dave sized this latest turbo and setup for more of a top end charge. From Dave and Robert’s account this top end is very strong and their goal was achieved. A larger turbo and much larger injectors were used, which do not perform as well at the low end and in normal use or driving conditions. The result is this setup is closer to the Hayabusa dyno chart from above, although not nearly as peaky.
The labor and cost needed to achieve Rabtech’s and Dave latest build would be exorbitantly high for most anyone attempting to buy this Haltech ecm setup and duplicate the results shown above. By Dave’s account he had at least 40 hours into tuning alone and finding someone of his talent and skill level at anything less than $100/hour would be difficult. The base tune provided to him was of almost no use and severely lacking from his description. I have been in this situation many times with different types of aftermarket ecm systems, and it is an ugly deal even for someone who really understands what needs to be done. Many kudo’s to Dave for being able to achieve what he did.
From a reliability and capability standpoint the Haltech ecm is not even in the same arena as the stock MEFI ecm. None of the aftermarket ecm’s are, although many do have nice features. The MEFI6/E78 controllers encompass GM's best engine management technology up to that point in time. Think of it in terms of the R&D and the strenuous testing, validation time, and dollars spent on an ecm and control system of this nature versus something like an aftermarket ecm. The aftermarket companies are spending fractions of a penny on development and production for each dollar the OEM spends, and it is this way with any aftermarket versus OEM ecm or ecu, be it from Bosch, Denso, GM or whoever.
A good reliability example is the way it was recommended to mount Rabtech’s ecu in the passenger compartment to avoid heat. The reason for this is the failure rates are relatively high for aftermarket ecm’s in rugged environments compared to OEM ecm’s. You are not going to see Haltech, Fast, Holley or any of the aftermarket ecm manufacturers advertising their relatively high failure rates or quirky problems with software interfaces. Over the years I have experienced way too many of these hardware and software failure rodeos with these aftermarket ecm’s that turn into nothing but huge time and money sinks.
From a capability standpoint, it comes down to the complexity of the algorithms controlling the various functions, the granularity of control, and the robustness of the hardware implementation in the OEM ecm. Again, not even close in this area, especially in respect to detonation control and malfunction condition handling. Given the same engine hardware, on the same day, under the same conditions, with an optimized tune, the OEM (MEFI in this instance) ecm will outperform an aftermarket ecm. For an aftermarket ecm to perform close to equally is a huge win for that manufacturer. I have run these tests for an OEM. Some of the aftermarket ecm’s do have nice display readouts and logging if you like watching data, and for some applications this is extremely useful.
For those who can point out an instance of “my aunt’s girlfriend’s cousin had a PSI blown tall deck big block Chevy that picked up 100hp going from a OEM ecm to an (AEM, Fast, Holley, Haltech, Motec, etc.) ecm” I get it. Man bites dog in those .01% of cases. That does not apply here.
For those of you who want to “own your tune” (by the way, this forum needs a funny button like the other one), you can put a carburetor on your ecotec and you can twist the screw driver all you want.... you have full control! Will this work and run the engine... sure. Is it a good idea... not so much.... this is of course unless you get your jollies from that type of thing. For some that is the overriding factor.
So, with a Haltech (or other aftermarket setups), you have something less reliable, far more costly, and not as capable as the ecm you already have on the Slingshot from the factory. What you gain from the Haltech is being able to fiddle with it, and for this many props to Dave at DDM for the good result he got from what little he had to start with. I have to really applaud Rabtech for undertaking such a project, and at the end of the day, him being happy with it is the most important thing. Him pushing the envelop with all the things he has tried along the way benefits everyone with these vehicles.
Bob
