As TX2K13 begins to draw nearer, I have been slowly prepping for it and have come to a question I can't seem to quite figure out. I want to raise boost up to 30 ish maybe a little more, but for some reason we (tuner and I) can't seem to read anything abover 29psi of boost on hptuners. Also I noticed the rpd will say no data sent when boost is risen that high. Will 3.5 bar mapsensors help to correct all of this? I ask because if itll will help with it all for sure then ill buy them, but just saying $150 for 2 sensors that may not even be needed is alot. Thanks.

 

Are you talking about the 3 bar map senors that CED sells or they come with the GMS1?? I thought they were 3 not 3.5 lol I was also told our stock ones only read up to like 24 or something? I got them when ZZP tuned my car just cause I had a 50 dollar off coupon for giving them my cat lol.. not a bad upgrade for 80 bucks but in for learning.. 30 psi thats wicked man

 

Ya I already have the 3 bar sensors but for some reason I cant seem to read everythiung over 29psi. So thats why I'm looking into the 3.5 bar senors. lol An we go BIG in Texas so I gotta up boost at least for the weekend! haha

 

I've boosted above 30 once or twice. Lol. I use a mechanical boost gauge tho. In for 3.5 bar map info.

 

Did not know there was 3.5. I know there is A 3 and and 4 bar map

 

i was going to suggest manual boost controler as well lol

 

umm isnt 1bar = 14.5psi.... 3.5 bar u should be able to read no problem, i run 32psi (or ran) on my 58/57 used turbosmart controller and mech boost gauge had no issues?

 

I've never understood the whole 2.5 or 3.0 bar sensor thing anyway. I mean, considering that 1.0 bars = 14.5 pounds per square inch, then why is it that a "2.5 bar" sensor can't accurately measure much more than 23 or 24 psi?

 

I'm still tuning for boost reduction in the lower gears, therefore I do not have a manual boost controller. I wonder if this has anything to do with this situation. I have done 31 psi before however it can do it but you can't read what's going on and then it'll start missfiring at the very peak of boost. They do sell 3.5 map sensors but the are like $70 each. Haha that's why I'm just seeing if anyone had any info on this at all? Ill more than likely end up buying then but just wanted some input first, maybe I can save $140+shipping haha

 

^ exactly haha I believe it actually boils down to the atmospheric pressure, or sea level as well. I think that plays a role. Which is why it varies in different areas.

 

14.5x3=43.5
43.5-14.5=29

14.5 is 1 bar or an atmosphere. You times that by the the resolution of the sensor then subtract the barometric pressure of your location to get the total readable psi

 

^^ bam this guy! Haha genius! Well then that's what's the problem I guess. So then a 3.5 bar would benefit me correct?

 

Would but at that rate go to a 4 bar map and rescaleI. Rpd won't ead past 30psi I don't think but I'm not too sure. Never been past 27psi in my cars and the few times with the last one I did I was using a aem boost gauge

 

A 4 bar is restarted expensive haha it's like $380-400 for the 2 sensors

 

There you go, someone remembered physics in high school lol.

You always have to account that in the atmosphere generally there is 14.7* psi, or 1 ATM. You subtract that from the total boost you're seeing.

 

Ya^ and since I'm sea level I believe it's 14.7 exactly? Which would make complete sense why we can read anything over 29.

 

I knew the numbers, but not the math of it. I appreciate your having shown it to us, as it makes perfect sense to me now and I don't think I'll ever forget it. It's just common sense.

 

MAP sensor are only accurate up to 80% of there range.

I havent seen a 3 bar but a 4 bar would require a lot of editing tables not available with HPTuners.

If you find a Bosch sensor that has the GSM1 harness PM me a link and I'll send you a adjusted HPT file you can try.

But I'm running 32psi without issue the ECU just goes in to a default/closed loop/speed density mode.

--Christian

 

This is where I would buy the sensors that are 3.5 bar

Home ť Shop ť Sensors ť Pressure Sensors ť Bosch 3.5 Bar TMap Map Sensor with IAT

 

70 bucks for a sensor isnt ******* around. But then again you're pretty much at 600whp salazan. That's not ******* around either lol.

 

Ya true haha it's like they say pay to play, but sometimes playing is expensive haha

 

exactly lol, I won't argue with that!

 

Most of the bosch sensors have a bit of head room built into them, so even though they are rated for xxbar they can actually register a bit higher than that.

For example, the stock 2.5 bar. Technically they are only rated for just that, 2.5bar (250kpa or 21.7psi). However, as everyone is (or should be by now) aware, the 2.5 bar can actually register up to roughly 2.62bar (262kpa or 23.5psi) when monitoring the low res map.

The same thing holds true for the 3bar sensors. They are obviously rated as 3bar (300kpa or 29psi), however they should be able to register up to roughly 3.22bar (322kpa or 32psi) according to the sensor specs if scaled correctly.

As far as your RPD goes. That thing is absolutely useless for monitoring boost beyond 25psi and even up to that isn't always accurate. If you want an accurate boost monitor, get a mechanical gauge and ditch the rpd imo.

 

I have always been able to read up to about 32psi with the low res on hp. The problem is reading beyond that if there is a boost spike and being put into a limp mode. Your right on the borderline. The rpd does crazy things when it sees over 29psi also.I could build a file with the correct map sensor values but its a matter of testing it to see if there are other tables being scaled in the back ground like on the stg1 file. My guess is it will be fine since you can run the 3bar values on a stock file. If anything I could build the tune on a stg1 file with the 3.5bar values. Which would be the same difference as running 3bar on the stock 2.5 file.

Your car should be about ready up at the shop ryan. Now we need to get the extra injectors set up correctly to support that 30psi before you order new sensors. I would bet 30psi with the correct fueling is going to be pretty nasty on the street. Already is on 25psi.. Your really just starting to make that turbo work. At 30psi its really going to start moving some air.

 

That doesn't make sense. If you boost beyond the limit of your MAP sensor, why would the ECM switch to speed density? Speed density uses only MAP and does not use MAF.

On the LNF, it really doesn't matter if you go past the limit of your MAP sensor. On an LSJ, it is important to have accurate MAP readings because the injector flow varies significantly with a change in boost pressure. The ECM needs to know mass air flow and injector flow rate in order to deliver the correct amount of fuel. On the LNF, it is not as important because you have nearly 3000psi fuel pressure. Adding a few more psi to your boost does not significantly alter the injector flow rate. As long as you have an accurate MAF reading, your AFR will not change much because you raised the boost from 29 to 33.

FWIW, I have run up to 45psi boost several times on the dyno, running mostly E85 as well.(with GMS1 sensors) That's where you run into some real challenges based on running out of both fuel pumps, DI injectors, and 5th injector.