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Discussion Starter #1
I have a stock bottom end with forged pistons, stock ported heads a Ford racing F cam, GT 40 intake, a On3 performance base 5.0 kit and my car is tuned with a SCT chip. I have a MSD BTM ignition box with boost retard and my tuner has my boost retard set on 3 anyone have any suggestions my A/F stays between 10.0 and 10.8 under load and my base timing is set at 10*
 

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Not sure what you are asking, but this is just my opinion only:
On our customer cars, it totally depends on alot of factors, one is we live in a different climate then yours:
The MSD BTM takes out timing for every pound of boost (you didnt say how much bosst you are running), but if its set at "3", and your boost is 10 pounds, then you are taking out 30 degrees. Im not sure why your tunner set it on 3 for you because he couldve took out timing with the tune, but we do it with full advance capability when not in boost so the drivibility and response is good, It could be thats how he did it? And the A/F ratio you are running is a tad rich for us, we usually go for around 11.5 -11.7, but again every application is different, and maybe your tunner found the best power at your setting. Hoped I helped a little if any, Good Luck!
 

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Discussion Starter #3
Thanks that does help I thought that was how it worked, im running 12.5 psi, and my car only made 350 hp and 440tq I think.it would make more a little leaner but do you think it would make that big of a difference? Its tuned with a SCT chip he said they usually can't take timing out with those chips for some reason
 

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Jersey True Street Guy
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Stock electronics don't have MAP sensors so they can't retard based manifold pressure, hence the regular use of BTM's.

Anderson PMS uses a MAP sensor and somehow by way of the piggy back allows control based on boost.

I would agree your A/F is a tad rich. Is this terrible? No, probably not. But you will make less power, burn more fuel, gradually foul plugs and could probably get some fuel washdown down the cylinder walls.

3 degrees sounds aggressive in terms of taking timing out but as stated above it is the big picture that makes a difference. You have to look at the map of where timing ends up once the retard is provided. On my previous 93 cobra I ran 2 degrees on pump gas and 1.5 on race gas. That was with an autologic chip that we had clarity on the base, non boosted timing. Without knowing what was done in the tune, it is hard to determine.

I agree with wizwrath, I have been playing with timing over time and the car runs the best with more timing in the lower rpm's without boost. This is much easier to manage with a DFI because it is clicking buttons to evolve it. A lot of times tuners are concentrating on WOT and not necessarily the other parts of the tune. For example, timing being too low in the transition area on a turbo car can slow the staging process because boost builds slower. Won't change anything at WOT on the dyno though.
 

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Its tuned with a SCT chip he said they usually can't take timing out with those chips for some reason
That's a retarded statement. I think you need a new tuner. On a good note, I think its a little down on power but in the close range of your combo. Use the chip to adjust the timing and turn the BTM off. My completely stock motor @ 8lbs made more power at 370/450 than the 12.5lbs your running.
 

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Jersey True Street Guy
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That's a retarded statement. I think you need a new tuner. On a good note, I think its a little down on power but in the close range of your combo. Use the chip to adjust the timing and turn the BTM off. My completely stock motor @ 8lbs made more power at 370/450 than the 12.5lbs your running.
I'm not sure it is retarded, perhaps just not a completely informed statement. A chip on stock EEC IV electronics can have timing set for a fixed lets say "map" of boost on a combo that will not change.

It CANNOT adjust based off of variable boost like a BTM or a PMS.

If someone wants to be able to change pulley's and vary boost over time they will have to go back to the tuner. The BTM bandaids that.

Use anything with a MAP (PMS, DFI etc) and you eliminate the problem because you are tuning for a single static boost level.

Lack of understanding like this is exactly how people blow things up.
 

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Are you sure the knob is set to 3*. That would mean the nob is all the way to the right. The box will only take out a max of 20*. So if your initial is set at 10* and the ECU add 16* at WOT that would give you a grand total of 26*. So at 12lbs and the knob set at 3* the box will reach it's max of 20*. leaving you with a total of 6* of timing. That's less than than your initial setting. That could be were your missing power is.

My opinion, turn the knob off. Tune the timing with the chip. Stop the guessing game of how much timing the nob is taking out, and know how much your playing with at all times.

WARNING! Don't just turn the nob off without adjusting the timing on the chip, or you will be replacing head gaskets or worse.
 
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