PM sent.

 

erik, just because the pressure ratios aren't posted, don't for a minute think they aren't being done, atleast by us. My car has two 5 bar map sensors on it and two temp sensors. There is actually a secondary harness in my car for these additional sensors and a laboratory grade MAF sensor we use to measure MAF rates on new turbos we test.

BTW, did you guys dyno test those 65 mm throttle bodies before and after or did you just go on the fact that we did it and they made power?

I know another company on here sells ported parts, 65 mm throttle bodies too and has referred to OUR testing to sell THEIR parts.

Not to single you or any other vendor out but there is a lot of "riding on our coat tails of testing" that goes on on this board and in this community.

 

BTW, jmartinez, if you'd like to use our forums at www.buschurracing.com for any links to testing that has been done feel free to link them.

 

David

One thing that surprises is the amount of testing you do and publishing the results, Although I am sure you do keep some of it to yourself and I bet you get feed up with people quoting it and not give you the credit for it.

Mark

 

With all due respect, if you are using two 5bar MAPs to measure IC pressure drop or charge system pressure losses or compressor inlet depression then you are wasting your time--the measurement uncertainty is too high to be of value.

 

That's good to know


If that isn't proprietary data, it would be great if you could post that info (time permitting). For example, knowing pressure ratio information before and after the turbo would be extremely helpful in determining where backpressure is coming from if a turbo happens (for example) to underperform to expectations.

We use Aby's data from when he dynoed in front of 20 SoCalEvo members. It was an 8whp increase IIRC on his Evo running a TME...however the TB swap/test wasn't perfectly exact as the IM was ported. I would assume the gains would be larger going from a stock IM/stock TB to a ported IM/ported TB. I also think bigger gains could be demonstrated with a larger turbo (than Aby's TME) and a 65mm TB that would be similar to your 15whp gains.

While your results were/are encouraging, Aby is a data fiend who likes to back things up with his own testing/data acquisition/fact finding. I am sure that was required in his previous engine building/tuning experience at Cosworth and other places.

Me, I'm not nearly as wise

 

JKAV, I will keep your input in the back of my head, WAY IN THE BACK. If a sensor that measures down to a hundreth of a PSI (.00) isn't accurate enough I'd sure like to know what is.

 

Dave,

I think JKAV was talking about the error range of the sensor, not the resolution that it can measure to. Adding more decimal points doesn't mean anything if the uncertainty of the sensor is greater than the measured resolution.

I don't think he was trying to attack you...he was just pointing out a fact of sensors and uncertainties. Usually, a sensor that can measure higher values will have higher ranges of uncertainties.

For example, a 1bar sensor with a 2% uncertainty is .02 bar. A 5 bar sensor with 2% uncertainty is .1 bar.

I think he was merely pointing out this fact.


Eric

 

If Kavlico medical grade pressure transducers are good enough for the medical instrumentation field where life and death depend on accuracy, I suppose the 5bar sensor would suffice on the testing of pressure drop across an intercooler.

After all, the error rate on them is like 0.001% last time I checked.

 

That's fine but the AEM map sensors (SSI) has an accuracy of +/-.5%. That means at 40 psi that is +/- .2, yes TWO TENTHS of a PSI. As I said, more than accurate enough.

 

Thank you TTP. I just went to the website of the manufacture of the sensors to double check the accuracy, it is in fact the +/- .5% that I wrote.

I have also swapped sensors front inlet/outlet to make sure the readings were the same, I can't find a difference in one sensor to the next, with .2 psi at 40 psi that is understandable.

YEARS and YEARS ago we took 2 boost gauges and an two air temp gauges, mounted them in an aluminum panel and used them to do the same measurements. That was a real PITA as you had to watch 4 gauges and remember what each one said at the end of a pull. It worked but was tough to pull off.

 

It's 0.5% of full scale. In the case of the two 5bar sensors measuring intercooler pressure drop, its plus or minus nearly 1 psi. When you're dealing with pressures losses on the order of about 3 psi MAX, that degree of error makes the measurements essentially meaningless. It's not a slam, just stating facts.

And that doesn't take into account the temperature-related component of accuracy, which is heaped on top on that.

It gets even worse if you use a 5bar sensor to measure compressor inlet depression, where the uncertainty is many many times higher than the amount you're trying to measure.

Pressure drop measurements want a differential pressure transducer. Inlet depression wants an inches of water range sensor, and so on.

 

That is good enough for measuring boost pressures, but I think the point that JKAV was making is that that amount of error may not be good for smaller resolution measurements, like IC pressure drops, etc.

After all JKAV said:
He is referring to situations where you may be measuring on order of magnitude of 1 psi or less.

With a .2psi error, from run to run you can have a .4psi swing in your measurement. If you are measuring an IC that may have .7 psi pressure drop, your .4 psi error range is now a 57% error.

A sensor like TTP mentioned, with a .001% uncertainty would be more suited to measuring smaller pressure differences.

Again, he wasn't attacking you. He's just trying to help. No need to jump down people's throats when they are helping out.

EDIT: I see JKav already responded above while I was posting this.

 

JKAV, you sound like you read a lot of books, while you were reading I was doing worthless hillbilly testing.

Please entertain us all with some testing of your own.

Mine obviously sucks and all of the cars we build and the products we sell also suck.

BTW, in your avatar, you can add me to the list of who you drive crazy

 

Even when the tests are done, some one always has a problem with how the tests are conducted and the results are ignored.

The best bet is talking to your tuner about products and what they feel works best. I've tuned many, many setups and know what works and what doesnt. Some mixes are easier to tune than others and its repetitive.

Cheers!