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Discussion Starter #1
Trying to figure out if the 3 bar sensors used on the Cobalts, Solstice, Redline and HHR LNF's are the same part that is interchangeable among the ecotec lines, with the right calibration (tune)...

Been at stage 4 E85 for awhile at 25 psi, and it seems to have dropped off (not just because it's warmer out, but it wont hardly go past 19psi...I also get weird misfires and stalling when the engine is cold, and if I randomly stop at a light, AFR will go lean, it will sputter like crazy and sometimes die. My WOT AFR is also a lot richer than what the current tune is supposed to be set at, by almost 2 full points. Lots of research tells me that these symptoms point to a faulty MAP sensor, which pushing more than 22psi could have caused them to go out.

I've heard that our stock MAP sensors can only take about 22 psi, when there are a handful of guys running 25-26psi, and there happens to be another thread with a similar problem, so if these 3 bar sensors can work, maybe that can prevent problems for others in the future...
 

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I'm not sure but i read on another forum that it should work with these sensors.

Bosch 0281002845 TMAP

I'm probably gonna get modded for this. But this is a post from trionictuning by a member called nappe.

"I finally got my tune to a stage where I will need boost beyond the stock 1.37bar so I spent some time searching for suitable MAP and TMAP sensors.

I ended up ordering a pair of Bosch 0281002845 TMAP:s with wiring harnesses intended for the Ecotech LNF engine, thinking that GM is GM, they can't be that different :)
Turns out the MAP sensors plug right in and the adapter cables fits perfectly to the T8 harness!
For the p_Beff you will need a washer and a slightly longer screw to mount the sensor firmly.

I got mine from http://shop.zzperformance.com/store/p/1 ... nsors.aspx not by any means the cheapest on the net, but hey, the kit included the plug'n play harnesses.

I calibrated the sensors in my virtual car using TECH II and a pressure/vacum pump (Biltema), tried to get the 20-200kpa range to match the original MAP, above 200kpa the 3bar map starts to show slightly low but the error is not that big.

The calibration values I ended up using are:
VIOSSensorCal.p_AirInletTAB
309.50
3.40
VIOSSensorCal.p_AirIBefThrottleTAB
309.50
3.40

Turns out the OBD II protocoll only shows 255kpa (FFh) for intake pressure, so no OBD-logging above 1.54bar guys!

Took her for a spin and everything worked like before, just like expected.
Now the only problem is that the scenery starts changing real fast when testing these, I had the convertible on a dyno last week and got [email protected] / 314Hp/[email protected] (engine power) @1.3bar, the torque getting a bit thick for the bloody automatic gearbox there...
For the ones interrested: http://www.garaget.org/?car=175077"
 

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Discussion Starter #3
1.37 bar = 19psi, so that explains why I can't see any more than that it seems.

Just took both sensors out and cleaned them, the sensor in the boost hose was dirty as crap, manifold sensor was as well, but not as bad...Car seems to be a little better at idle, but it didn't fix the problem...

This is definitely useful information to anyone with the TD04 that's at stage 3 or higher, as the boost is near or at the point at which these sensors would start failing.

Btw that link is broken, here's the good one, ZZP Performance's website shows the kit for $150: http://shop.zzperformance.com/store/p/1134-GM-Stage-1-Sensors.aspx

HOWEVER, Jegs has the same exact sensors with the same part number, $23 per sensor: http://www.jegs.com/i/Chevrolet+Performance/809/55206797/10002/-1

If you know how to wire your own with the pigtail harnesses, you can save about $100.
 

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Yes there are certainly a lot of people running blind in regard to boost....and its not always the best approach. There are also a few software tricks to get more air by skewing the boost, but again not a good approach.

I'm glad to see some of you guys here take the initiative. If anyone wants to take on doing hardware, I'd be happy to help with the tune.


Sent from AutoGuide.com App
 

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Hey rabbit. You're a tuner so you probably know why so I thought I'd ask. Why is it much harder to tune for the t8 than it is for the cobalt side of things. Reading forms the lsj looks like they don't need to put as much effort to get more hp out of these engines. Yet on this side of the fence if we want more than 300 hp we automatically need new pistons.

Thnx <3
 

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The difference of a Cobalt or ION and the T8 is in the engine management control. The cobalts are very widely tuned by many people so its supply and demand thats all combined with an ecu os that is shared among many GM cars.


The 3bar Maps are possible on the T8 cars and the open source people are working on it too.... so maybe this is the point where the tuners take some first steps and responsibility and adapt their tunes to the 3bar's now instead of letting people run blind.
 

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Hey rabbit. You're a tuner so you probably know why so I thought I'd ask. Why is it much harder to tune for the t8 than it is for the cobalt side of things. Reading forms the lsj looks like they don't need to put as much effort to get more hp out of these engines. Yet on this side of the fence if we want more than 300 hp we automatically need new pistons.

Thnx <3
Because we are scared little *****es... to be honest.
There is no reason why cobalts can run 350WHP all day on pump gas and we can't run more then 300 crank.
 

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Gah3535 said:
Bosch TMAP...
This is the kind of info I like to see. More real-world technical info. Keep it up.

The myth about needing new pistons at the magical 300hp figure gets old.
 

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I don't think it's harder to tune for t8, it here are just way more cooks in the cobalt world. You can pretty much count us t8 tuners on one hand...... Limited bandwidth is it.

I've actually wanted to do a mod like this for a long time. In my short searching I did not find a suitable map sensor. So ill likely grab some and pop them on my test car soon I hope.

Running blind may not be the best term, and we still have airmass readings beyond that of the limit of the map sensor. I've never ignored the map sensor in any of my tunes too btw, however my stage 3 tunes do push it right to the limit.


Sent from AutoGuide.com App
 

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I'm in!!!!!!!

I don't think it's harder to tune for t8, it here are just way more cooks in the cobalt world. You can pretty much count us t8 tuners on one hand...... Limited bandwidth is it.

I've actually wanted to do a mod like this for a long time. In my short searching I did not find a suitable map sensor. So ill likely grab some and pop them on my test car soon I hope.

Running blind may not be the best term, and we still have airmass readings beyond that of the limit of the map sensor. I've never ignored the map sensor in any of my tunes too btw, however my stage 3 tunes do push it right to the limit.


Sent from AutoGuide.com App

Just finished my order. Should be in mid to late next week. I'll let you know when I have them and we can go from there.....;ol;
 

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Discussion Starter #13
http://www.performanceautowerks.com/catalog/product_info.php?cPath=334_387_393&products_id=1712

The cheapest I could find with the connectors and tmap sensors + pigtails.

http://www.bmotorsports.com/shop/product_info.php/products_id/1626

And maybe this pigtail. I'm not sure if these would be plug and play.

But apparently this link shows install of the sensors on the lnf engine.

http://www.crateenginedepot.com/pdfs/frsp19212711.pdf

Now all we need is some one to try these out <_<
These are the cheapest sensors, same from the link I posted earlier...http://www.jegs.com/i/Chevrolet+Performance/809/55206797/10002/-1, same ones the LNF's use, and same sensors that are in the big name kits like ZZP that want 150 bucks for them

I'm sure there are some sort of universal GM harnesses that fit it, all you would need to do is find them at a dealer or wherever and run the stock wires through them, the pinouts are all over the place on forums and whatnot. All the other kits that "plug and play" seem overpriced just for convenience, when wiring them yourself takes 5 minutes and saves you 50-100 bucks.

That, and rescaling the MAP sensors in a tune would let the ECU read up to 29 PSI ;ol; not like anyone would run that much on a stock turbo...but it opens up some new roads
 

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All right. So we just need to find the plug and run the stock pins through them? I'll look through the cobalt forums. I really dislike the idea of having to splice harnesses. Are you planing on running these sensors?
 

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Discussion Starter #15
I'd like to, hell I'd even guinea pig for them...just for the sake of doing things the right way... I just can't adjust the MAP scaling. But mainly I don't quite like the idea of running more than what the ecu can actually read.

There's only 3 wires on the sensor going into the boost pipe, and 4 wires on the sensor going into the intake manifold. If you have the connectors that snap into the new 3 bar sensors, just take the wires from the stock connectors and run them to the corresponding spots in the pinouts, and boom. Done
 
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