After turbo and tuning - Stock display is off Fuel Gauge, MPG & Range

Quote from 2W2X1

Since adding the turbo and tuning from MeFi Burn Bob, my SS suggests I am getting 48mpg and my range is about 485miles. I know that is BS and suspect the larger injectors are to blame for the miss calculations.

Anyone have a solution to fix this? Is there an upgrade to the tuning to assist? I could care less about MPG as calculated by the computer, but relied on range in the past. I found myself in a situation this weekend on a long ride that left me with 2 bars showing fuel remaining and I sputtered out and stalled. Felt like I was running out of gas and limped into a station. Fueled up and all was right. I guess I am going to need to baseline my average range on a tank of gas and just manually watch it if I can't rely on the computer to tell me accurate fuel level.

Dave@DDMWorks what'chu got?

When going to the 2 bar MAP setups and the larger fuel injectors, the estimated fuel economy calculations are off. From what we can tell the gauge measures the pulse length of the fuel injector to calculate fuel flow and estimated MPG. Since the fuel injectors are roughly twice the size of stock fuel injectors, those injector pulse lengths are about half of stock, which results in an estimated MPG rating about double of actual. All of the kits we have seen with the larger injectors have had the same reports, unfortunately 48mpg is not something that is possible with a Slingshot

Let me know if there is anything else we can answer or help with,

Dave

Quote from Dave@DDMWorks

When going to the 2 bar MAP setups and the larger fuel injectors, the estimated fuel economy calculations are off. From what we can tell the gauge measures the pulse length of the fuel injector to calculate fuel flow and estimated MPG. Since the fuel injectors are roughly twice the size of stock fuel injectors, those injector pulse lengths are about half of stock, which results in an estimated MPG rating about double of actual. All of the kits we have seen with the larger injectors have had the same reports, unfortunately 48mpg is not something that is possible with a Slingshot

Let me know if there is anything else we can answer or help with,

Dave

I haven't done these upgrades, but am planning on it sometime in the future, so inquiring minds want to know. Is there a fix at all? Is it upgrading to something like the Haltech?

I'd get one of those now if it was 100% compatible, but my understanding is that you lose cruise control, and yeah, I like to use that on the highways.

When we installed the Haltech the fuel mileage readings seemed to get corrected.

With the turbo and the big injectors its not pretty but it seems accurate

Ah, nice, thanks for the info. Is cruise the only thing you've noticed not working with the Haltech?

I'm assuming since you have that, and it has an OBD-II port? You have that option for a lot of other things, correct?

Quote from wokka

I haven't done these upgrades, but am planning on it sometime in the future, so inquiring minds want to know. Is there a fix at all? Is it upgrading to something like the Haltech?

I'd get one of those now if it was 100% compatible, but my understanding is that you lose cruise control, and yeah, I like to use that on the highways.

There is no fix that I know on the stock ECM with a 2 Bar MAP sensor and the larger injectors.

On the Haltech's. as MACAWS said, the fuel economy appears to be accurate. The cruise control is supposed to be taken care of on the latest firmware Haltech, we have 3 Slingshots here all doing Haltech's right now and another Slingshot with a different aftermarket ECM we are also testing. They should all have cruise control working from what we have been told with the latest firmware from Haltech. Once we get some more information on the cruise with the Haltech for sure, we will post an update also.

Hope that helps,

Dave

Quote from Dave@DDMWorks

There is no fix that I know on the stock ECM with a 2 Bar MAP sensor and the larger injectors.

On the Haltech's. as MACAWS said, the fuel economy appears to be accurate. The cruise control is supposed to be taken care of on the latest firmware Haltech, we have 3 Slingshots here all doing Haltech's right now and another Slingshot with a different aftermarket ECM we are also testing. They should all have cruise control working from what we have been told with the latest firmware from Haltech. Once we get some more information on the cruise with the Haltech for sure, we will post an update also.

Hope that helps,

Dave

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yes it does, thanks much Dave!

Quote from wokka

Ah, nice, thanks for the info. Is cruise the only thing you've noticed not working with the Haltech?

I'm assuming since you have that, and it has an OBD-II port? You have that option for a lot of other things, correct?

Traction control and Cruise control are the 2 things that are missing from the Haltech right now.

The other ECM we are working with should have both of those working and Haltech should have the cruise control taken care of also, but we have not confirmed it on an install here yet.

Quote from 2W2X1

Waiting for final report on the newest Haltech and OTHER install. That may be my next mods.

Can you disclose the Other?

We are very interested also in how the Haltech works out with the new firmware, this latest build will be making 1HP less than rabtech

The other ECM is actually the Emtron, it was on a thread on the other forum awhile ago. It allows a lot of full custom maps to be created and has on the fly traction control via a cockpit mounted knob. It will most likely be the next level above the Haltech with a lot of neat features for really custom one off builds, which seems to be what we are doing a lot of these days. Once we get it worked out, we will post up about it also.

Quote from Dave@DDMWorks

There is no fix that I know on the stock ECM with a 2 Bar MAP sensor and the larger injectors.

On the Haltech's. as MACAWS said, the fuel economy appears to be accurate. The cruise control is supposed to be taken care of on the latest firmware Haltech, we have 3 Slingshots here all doing Haltech's right now and another Slingshot with a different aftermarket ECM we are also testing. They should all have cruise control working from what we have been told with the latest firmware from Haltech. Once we get some more information on the cruise with the Haltech for sure, we will post an update also.

Hope that helps,

Dave

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Cruise Control!

What do I have to do to get back cruise?

Quote from MACAWS

Cruise Control!

What do I have to do to get back cruise?

I'll let you know how it works out, installing some new firmware now on the Haltech, working through a couple things with the new install.

Quote from Dave@DDMWorks

I'll let you know how it works out, installing some new firmware now on the Haltech, working through a couple things with the new install.

Great news

Thanks

Quote from MACAWS

Cruise Control!

What do I have to do to get back cruise?

AND!

My family has always assumed our roots traced back to England, but in my case, I assume I must have some Scot in me since I don't like spending money unless I feel something is absolutely needed. In my case, I feel the only need for the aftermarket ECUs is if you're really after high performance and want maximum ECU tuning flexibility. I prefer having the stock ECU along with properly functioning nanny controls and would prefer having them if I were to go with an aftermarket ECU.

That same reasoning is why I like the TRAKHAMR 4-wheel conversion since it maintains the ABS and TC systems (and I assume the CC, as well). Now if I can just win the Lottery! (I tried multiple edits to get the smiley face with two thumbs up. It shows in Edit mode, but once I save, I end up with just a thumbs up!)