ok, I am about to install my 3 bar map sensor. I found the offset number, scale numbers and which wires to connect where. The one question I have is, in the datalogit when you change the scale and offset do you then have to change the values in the map reference section of the datalogit? And if so what values do they need to be? This is under the settings #3 section of the datalogit.

Thanks

 

bump

 

By installing the 3-bar, you will now be able to reference a p-value over 1.15 kg/cm^2, aka 21500. This means if you don't change the p values in settings 3, then you will be using p18 at 1.00 kg/cm^2 (14.22 psi) and p19 at 1.2 kg/cm^2 (17.06 psi), and any boost level in between will be extrapolated between those two points.

You should look at you fuel delivery capability and adjust if you want additional granularity. If you're not running at least a 550/1300 setup and/or an adjustable regulator for more fp you should be careful before going over 14 lbs if you run a turbo of t04S size or better due to the increased fuel needs. Most guys want additional granularity so they do the lumping in the p11 areas so they can split out p18,19, and 20 for greater granularity for fine tuning afrs. It just depends on what you plan on doing.

At 15 lbs I'm running duty cycles in the 90% range on my 550/1300 setup, so I need to go to 850 primaries, 1600 secondaries, or both along with a new regulator and other items (103 octane unleaded) to explore the upper reaches of my t04s's capabilities.

Beast

 

Cool thanks, I get what your saying. I was thinking that you had to re value all the P cells to map the upper pressures of the 3 bar map sensor. But sense you will not hit those upper pressure values (unless you swap turbos and others) that the new map sensor can measure, then there is no need to map out those values or even put them in.

So just change the upper resolution in the last p cells. To do this I would have to bunch up some of the lower p cell numbers (places in the map that I never hit, I'll have to look at that) and then add those cells to the upper level with less of a difference between each cell?

Thanks, I need my WB back.

 

Unfortunately I don't get you're saying. Swapping turbos has nothing to do with the boost levels you will see - your method of boost control is what will regulate that. You can still set your regulator to boost greater than 1.4 kg/cm^2, but if you keep the defaut settings for the p values, you will peg out at p20. The 3-bar will still give you a reading of say 2.8, but the p20 value is not set for greater than 2.4 (24000) to start. How efficient your turbo is will affect the power and heat that your are generating at that boost level, and you will run out of fuel (if you plan on sane afrs) long before you get to that assuming your still running a stock fuel setup.

Yes, you need to 'bunch up' the lower p values (either in the NA area (p < 10000) or you can bunch up in the low boost area (say p between 10000 and 170000) as you said, in order to free up additional granularity for your upper values, but it's not that you never 'hit' them. You have to pass through them on the way to higher boost levels. You just might not spend much time in those areas if you are hard on/off the throttle during most of your driving, such as under drag conditions. However, under road track or street conditions, you may run partial boost regularly. However, having one cell represent 5 to 10 lbs of boost instead of several should be ok if you're happy at just running a tad rich under low boost, since you can run afrs of ~ 12.5 at 5 lbs, but at 10 and greater you want to move from 11.2 to 10.5 depending on the quality of your gas.

Again, it all depends on what you want to use the car for. Some folks who are hard core develop separate maps for street, drag, and road track, since you'll run different styles of driving and boost between them (at least, I don't know of anyone running 30 lbs of boost on a track like Laguna Seca - you'd swap ends so fast you wouldn't know what hit you).

Beast

 

Well I didn't mean how you regulate boost. I meant, If I swap out my non seq twins for a single that can put out 25 psi instead of 17psi, then I will need to change the p cells for fuel correction at that level. IE above 24000, like you stated above. Sorry I have a hard time putting my thoughts in writting.

Thanks, this helps a bunch. I will go log some more runs with light throttle transitions and heavier transitions. I will do this at my two favorite boost settings (7psi and the 14 psi). Then I will bunch up a few of the cells in the 0-5psi range like you said.

 

Here's a tip, use a hand pump and map out boost psi vs boost value in the PFC so when you change the P-row boost values on Settings 3 you will know what each row represents for boost.

I modified mine so that each of the top 6 or 7 rows correspond to a boost setting no more than 2 psi psi apart. This gives good resolution for tuning. The upper two rows are above where I normally run so I can setup a safe rich conservative timing row for overboost conditions.

Here's an example:

prow PFC PIM PSI of boost
P18 23300 19 (highest I normally run)
P19 24000 20
P20 25500 22 (setup safe for overboost)

Your map sensor may be a bit different so do your own testing. Don't forget to adjust fuel and timing after adjusting the prow boost value because the PFC doesn't adjust these for you. If you plug in these values above for P18 but forget to increase fuel and retard timing you will be running your old 14 psi fuel and timing at 19 psi!!!! Can you say rebuild?

 

Thanks. I haven't installed it yet, but very close. I will tread very lightly here and keep all that in mind. Thanks again.

 

Another question. How would I come up with the timing numbers in the leading and trailing when I add resolution for higher boost values?

 

Timing is a black art in the rotary world, and secrets are kept pretty close. The octane of your fuel, the boost level, porting, heat, and egt's all affect what those settings should be. The concensus is ' advance it as far as you can without blowing up', but just how far that point is is up for debate. You find out once the motor goes pop.

Do a search on Timing (in the title of the thread). There are two good threads out there. Getting an EGT gauge seems to be the best thing to do, along with dyno tuning. You advance your timing until the dyno shows you're not getting any more power, and your egts stay in a certain range. Once your egt's start going up past the range, you know to stop. For the really good tuners they use headphones to make sure knock is under control - if you advance and hear more knock, then you've reached the point where you need to back it off.

Sorry I don't have more definitive answers on that one. These are the dark secrets of rotary tuning, like magicians secrets. You have to learn by doing.

 

Wonderful, I get to blow my engine.

So your suggesting to take the timing numbers that are already in the upper cells and maybe advance (or would we want to retard first) those into the cells that I am adding for higher resolution at higher boost settings.

I have to add that I am changing my map sensor to push my boost levels above 1.2 bars.

 

I don't plan on running past 18 psi until later on, so I'm not qualified to answer your question. The consensus on timing at 15 to 16 lbs is to run 12 to 14 advanced at peak torque with ~ 10 deg split. Boost beyond that, I'm a noob just like you. I look forward to learning - I have 30 gals of 103 unleaded from VP sitting in the garage waiting for the day.....

Send me a PM with an email addy and I'll send you the map I'm using (it uses the timing from Wargasm's map - he's a good guy with a similar setup to mine). After that, you need to find someone else. I'm in the same boat as you.

General rule of thumb, you'll want to retard and add fuel as you go up in boost. Past 20 lbs, you have other issues like apex seal boost blowby, eccrentric shaft flex, and dowel pinning you'll want to do - that much pressure against the housings will make the plates shift around (I am pinned, too).

Beast

 

Wel I still have a way to go to get there.

The thing I notced is the first four rows, almost, can be nulled into one. That would give you three more at the top end. That might be enough for me.

Also, is it a good idea to have the 20th row set up to be an over boost row, with timing retarded and lots of fuel?

 

Yes, I never want to get to row 20 - I have it set with overfuel and only around 9 deg of timing. In reality my motor would go because my injectors can't get that much fuel - I'm already right at 88 to 90% at 15lbs with 1300s.

Yes to rolling the n/a numbers together. As long as you're in the 12 to 14 aft range under no boost, you'll be fine.

 

Wow, your at 88% or 90% at 15lbs of boost at what RPM? I need to look at mine but I have 1300cc too and I think I only see about 70% at those levels (near red line). I will watch those on theway home and see if mine are like yours.

 

Still too rich - running mid 9's afr and stumbling a bit. Slowly tuning it out - pulling fuel about a half of a percent at a time. I should be in the mid to low 80's once I get it right.

 

Yeah, I am still pulling fuel out of mine too. I see AFRs of 10.5 and less under boost. I have started by pulling .2 out of the AFRs at a time. Not sure what % that is though. And I am still backing them out. I think I would like them to be at a solid 11.0:1 under boost (14 psi)

 

Ah, at 14 psi I'm running in the 70's, too. You'll be surprised at how much more fuel you need at 15 and 16 bls. Remember that this flows SOOO much more air(a t04s vs. stock twins) that each tick up in boost requires almost a logarthmic (sic) increase in fuel. That's why guys going 16 and over go to Aeromotive fuel pumps and SX fpr's....and since I"m running 15lbs of boost, I need more gas, hence the high 80's duty cycles. Also ported, don't know about your setup, but porting will also add more air and therefore need more fuel. No two port jobs are alike....

Gotta go - taking my wife to see The Producers tonight....

 

mines ported with non seq stage 2 twins. I also have all the other goodies to go with. PFC, FMIC etc.

Right now I am taking info in and watching how mine acts. Still gathering data. I will bump my boost up and watch the AFRs and injector duy cycles at greater boost levels (15-16psi).

 

Let's clear up some of this mess.

If you are changing the upper p-rows as I discussed then you can simply change the timing to be equivalent to the same or similar boost value in your old map. You likely have access to a bunch of maps so study them, read posts within this and other forums and make informed changes. Given the tons of variables from one car to the next you really are on your own to pick a tuner or diy.

About fuel, there is little addl fuel injector duty cycle required to go from 14 to 15 or 15 to 16 psi boost IF your fuel system can maintain proper fuel pressure and you run a resonable AFR (maybe 15 to 40 hp difference). Think about running 10 vs 11 AFR ... that's 10% difference in injector duty cycle. I run well over 11.5:1 AFR at 19 psi boost but WI makes it possible (no anti-det plugs here).