Sorry for bumping an old thread, but i was wondering where this ended up. To the parties involved in testing, did you ever run a MAP in place of a TPS for a boosted application? Did anyone ever get to look at the datalogs running the MAP in place of th TPS?
This is a really interesting idea. I'm not entirely convinced though that this will work any better than an Alpha-N tune (for streetability at least). With a map sensor in place of the TPS, you'll have to learn to be much lighter on the throttle. That is, 20% throttle at idle and low RPMs may correspond to 100kPa, whereas at 4000 RPM, it may only correspond to 50 kPa. So, you're more likely to jump into PE mode at lower engine speeds if you rely on your map sensor to determine PE. In any case, this is a neat idea and hopefuly an easy fix for some boosted ECOs out there. Good luck.
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Remember we have TPS vs RPM for PE engagement, so we can adjust enrichment delay if it becomes touchy. The RPM delay would be crucial in the case your describing as well. HPT basically told me to piss off regarding making our VE table axes editable, but there might be a guy who can do it. I emailed Vince@Trifecta with this thread referenced. He's done a custom OS tweaks for the E69 bosch controller (LNF), which is way more complicated than our P11. If we had linearly scaled TPS axes in our VE tables, this would be worth a try in my opinion, but as it is, you could run a 3-bar map to the tps input and still only get 2-3 rows in boost, and you may only use 1-2 of them. With linear scaling, you get four vacuum rows, and six boost rows, with linear interpolation between them.
We'll see...
I really think many of you guys/gals should just switch over to MS-II Extra.
16 rows of vaccum and 16 rows of boost (or any combination of 32 rows you'd like).
I have no signiture
is there any reason why someone with computer skills, code and program writing, cant get crazy with this stuff and change what we need? HPT *could, and has for other OS's so why cant average joe screw around with stuff and figure it out? i by no means even know what is involved but i know there are people out there that could do this. correct?
someone use ur magical skills of computer programming and hack my HPT's!!
gmanz24 (The Bash Whore) wrote:is there any reason why someone with computer skills, code and program writing, cant get crazy with this stuff and change what we need? HPT *could, and has for other OS's so why cant average joe screw around with stuff and figure it out? i by no means even know what is involved but i know there are people out there that could do this. correct?
someone use ur magical skills of computer programming and hack my HPT's!!
Yes - his name is Vince and his company is trifecta tuning. He does amazing custom work but this forum pissed an moaned too much about canned tunes. He offers tuning for our OBDII platforms (LN2, LD9, L61). He's re-written LNF/bosch code that HPT said couldn't be done. He's cracked tables LONG before HPT has, some they haven't touched yet. The man's got skills, whether or not people HERE like canned tunes!
I tried to get people to open their minds but everyone laughed off the idea and called it a waste of time/money.
I'll tell you this - Vince has some things under his belt for our platform that boosted eco folks would cream over.
Ok, over a year later I just wanted to post up and put this to bed, since the other guys who claimed they tested it never finished with results.
I wired my 2.5bar tmap into the TPS output, just as described by the OP. Doing this, and logging the stock 1 bar map, approximately 48% TPS on the scanner corresponded to "boost" (also confirmed by key on engine off readigns). That means, on this particular sensor, we would have two rows for boost in the high rpm VE table, and three in the low rpm table(s). I set the TPS PE delay to 48% accross the board and went for a spin. Note this was on an M62 eco.
Fueling in boost was remarkably consistent/even, as you'd expect for speed density. That, and the fact that the car pulled enough vacuum to still enter DFCO were the pros. The biggest downside was that the car did not pull enough vacuum at idle to register 0% TPS. This means the IAC doesn't cycle, and after the first couple key on cycles, i had hanging idle north of 2000rpm, sometimes hanging around 3000rpm. I toyed with the idea of a voltage divider, or physically stopping the IAC, but at the time i wasn't down for the extra hassle on a daily driver.
This is strictly my opinion, but at least on a manual trans car, if you could somehow conquer the idle problem, you'd have a shot. Otherwise don't waste your time here, it's a lot of drivability sacrifice to make for two rows (maybe three on 3-bar i'm not srue) of boost tunability..
oldskool wrote:Ok, over a year later I just wanted to post up and put this to bed, since the other guys who claimed they tested it never finished with results.
I wired my 2.5bar tmap into the TPS output, just as described by the OP. Doing this, and logging the stock 1 bar map, approximately 48% TPS on the scanner corresponded to "boost" (also confirmed by key on engine off readigns). That means, on this particular sensor, we would have two rows for boost in the high rpm VE table, and three in the low rpm table(s). I set the TPS PE delay to 48% accross the board and went for a spin. Note this was on an M62 eco.
Fueling in boost was remarkably consistent/even, as you'd expect for speed density. That, and the fact that the car pulled enough vacuum to still enter DFCO were the pros. The biggest downside was that the car did not pull enough vacuum at idle to register 0% TPS. This means the IAC doesn't cycle, and after the first couple key on cycles, i had hanging idle north of 2000rpm, sometimes hanging around 3000rpm. I toyed with the idea of a voltage divider, or physically stopping the IAC, but at the time i wasn't down for the extra hassle on a daily driver.
This is strictly my opinion, but at least on a manual trans car, if you could somehow conquer the idle problem, you'd have a shot. Otherwise don't waste your time here, it's a lot of drivability sacrifice to make for two rows (maybe three on 3-bar i'm not srue) of boost tunability..
this IMO is very promising. I will be in touch with you later today sir. if wiring in a 3 bar map sensor, would this help with the idle issue?
The problem is the PCM needs to see ~0.5V to register 0% TPS to go to idle tables and cycle the IAC. If you found an x-bar map sensor that put that voltage at about 22" vacuum, you'd probably get away with it. On the tmap, that voltage is in vacuum well below what my car pulls at idle. The tmap voltage seems to bottom out at a full atomosphere of vacuum (0-5kpa absolute), which we never hit at idle.
Of course, the flip side to this, is if your car reads 0.5v or less at less vacuum (higher absolute pressure), the car may be more prone to go to idle tables while you're still on the gas, such as cruising conditions. IDK if it's a big deal, but it's just another thing to keep straight in your head when tuning - if the car is cruising and reads 0%TPS, you'd need to tune the idle table in that region. Also along those lines, you'd need to seriously tweak your DFCO settings to avoid fuel cut while you're still lightly on the gas, in other words, if your map voltage bottoms out at 35kpa absolute for example and you pull 30 kpa while lightly cruising - you're at 0% TPS.
In any case, looking forward to the discussion
A simple circuit that integrates the tps into that map signal would get you want you want. Just make a simple circuit such that when the tps is at zero throttle it give that input to the computer and all other times it give the tmap to the computer. I've talked about this before and we decided it wouldnt be a good idea because the car may never go into idle or dfco. And I may have just thought of the circuit off the top of my head 30 seconds ago, though it would be easy to make with just a h bridge, an or gate, and a resistor that drops 0.5 volts to a low enough threshold to no trip the or gate. I'm very tempted now to try this alpha-n sucks.
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Ok, i suck with electronics, but a circuit that "integrates the tps signal into the map"? How does that work? Do they share 5v ref and low ref? Or is this an entire wiring project? I really need you to spell it out for me like wire for wire because i just don't have the background to envision how what you are describing could possibly work the way we want it to.
oldskool wrote:Ok, i suck with electronics, but a circuit that "integrates the tps signal into the map"? How does that work? Do they share 5v ref and low ref? Or is this an entire wiring project? I really need you to spell it out for me like wire for wire because i just don't have the background to envision how what you are describing could possibly work the way we want it to.
He's talking about a simple electrical switch (H-bridge). You determine the threshold voltage you want to switch from the TMAP input to the TPS input and build the circuit around that. The only way you could really incorporate/mix both the TMAP and the TPS on the same line would require frequency modulation, for which I wouldn't expect anyone here to know how to do.
I have no signiture
basically you would make a small prototype board. Its inputs would be the TPS signal wire and the TMAP MAP signal wire. And what it would do would be. If the TPS is anything but 0.5V send the car the map signal if it is 0.5V send the car the tps signal.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
it sounds neat, but if it's over 99.9% of our heads, then i'd need to see it work to believe it. Also, this just may be semantics, but you said anything "but 0.5V" when we want anything less than or equal to about 0.5V.
That's not to mention the reprocussions on the acutal tune. When exprimenting I considered a toggle switch to go back and forth betwen the two inputs, but thinkitng about it, you're opening up yourself for a disaster to tune taking voltages from two sensors in the exact place where they don't "agree" with the actual load. It may not be the end of the world because in the condition we wanna manipulate, the car would almost always be in closed loop, but i'ts still something to think about.
Custom circuit has now entered the design phase and proof of concept phase in conjunction with TunerTools LLC.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Leafy (Club Jeffie FEA man) wrote:Custom circuit has now entered the design phase and proof of concept phase in conjunction with TunerTools LLC.
I'm very much looking forward to results!
After we make it work we're working on a digital box, basically a piggy back that puts the two signals together and lets you run alpha-n up to a certain throttle position, then switch to map. It'll also let you rescale the map and tps signal to let you use more of the cells on the maps. And it will have adjustable "stomp comp" better known as transients. And it'll likely have a boost controller as well, just for fun. And it'll need an rpm signal as well but thats no big deal, it'll be the only piggy back in that actually supports our crank trigger wheel.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
That's all sounds great, but all we really need is a way to switch to TPS input when the throttle body is closed. I respect your desire to go above and beyond, but based on what i've seen, it need not be fancy. If the switch occurs at any throttle position >0, i think we are going to have some overlapping load rows in the VE tables, and there for would never be able to tune them properly. Maybe that's a big deal, maybe it's not, but i'd envision the switch over to tps at 0 would lead to best drivability. Also, I assume you aren't actually rescaling the load rows as we see them in hpt, but rather somehow manipulating the signal - a fake within a fake? I guess everyone has their limitations on what they will do to manipulate the stock systems, and that may be past my limit lol.
To reiterate, the problem with running an x-bar map in place of the tps lies in the low voltage where map and tps signals disagree at the same loads (relative to what we can tune in hpt) if that makes sense. Map doesn't bottom out when tps is 0...
Yeah, it would be a fake within a fake. And our computers dont have stomp comp, being alpha-n take care of that on its own. We are worrying that going speed density we will need to add that or make it stronger.
1994 Saturn SL2 Home Coming Edition: backup car
2002 Chevy Cavalier LS Sport Coupe: In a Junk Yard
1995 Mazda Miata R-package Class=STR
Sponsored by:
Kronos Performance
WPI Class of '12 Mechanical Engineering
WPI SAE Risk and Sustainability Management Officer
Ugh...lol if you want to do all this fancy stuff with the map/tps swap/hack for your own benefit, feel free. If you want to make good financial use of your time and effort, "KISS" (keep it simple ******). Hint hint LOL.
Now this is interesting!
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Old Motor: 160whp & 152ft/lbs, 1/4 Mile 15.4 @88.2
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