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low map pressure

Posted: Mon Mar 15, 2010 11:35 am
by nunoctr
Hi Hondata,

Can you tell me if this is normal:
I have seen 2 datalogs of 2 FN2 civic with diferent intakes and OEM TB, both had normal wot map pressure between 1000 and 950.

After installing a bigger TB (TSX one) both cars have very low map pressure start at max 940 and goes to 900 at rpm cut.

I have seen datalogs with spoon big TB and the pressure was the normal 1000 and 950. Seen datalogs from 2 FD2 with bigger OEM TB and the pressure was the normal 1000 and 950.

Why the TSX TB cars have lower map pressure? Can this affect the power because this cars are not runing in the 10 column at wot for example?

Can be a leak?

Thanks in advance

Posted: Mon Mar 15, 2010 12:27 pm
by _Mozz_
Wile on that subject,

I use a 70mm Sponn TB, and my presure is at 980mBar @ 3000rpms finishing at 945mBar @ 8600rpms

But..., I realised that at WOT, the throttle Pedal never goes past the 91% mark, and on the tables it doesnt go to colum 10 in High Cam (does on low cam)!

Thoughts??

Posted: Mon Mar 15, 2010 12:46 pm
by nunoctr
paulo your datalog is normal.

Posted: Mon Mar 15, 2010 12:54 pm
by mw1978
NUNO Dawid using the same TB as I and he did not have problems. You sow his dyno!

Posted: Mon Mar 15, 2010 1:26 pm
by _Mozz_
nunoctr wrote:paulo your datalog is normal.

Normal?

So is it normal the Pedal at 91% max, and no colum 10 at WOT?

Posted: Mon Mar 15, 2010 1:39 pm
by nunoctr
yes. the 91% is in all cars. It's 100% but don't know why only read as high as that.

When you are above 960 map pressure it's at column 10, only near the end goes down that and goes to column 9. Clean your air filter and you can see a improvement

normal.

Posted: Mon Mar 15, 2010 1:44 pm
by scareyourpassenger
This was fixed in the latest release according to the release notes.

Posted: Mon Mar 15, 2010 1:52 pm
by nunoctr
scareyourpassenger wrote:This was fixed in the latest release according to the release notes.
don't think it'sthe same problem. That was dataloging with no computer.
This a "problem" with the TSX TB. The question is, is this problem?

Posted: Mon Mar 15, 2010 10:55 pm
by mw1978
Nuno maybe my MAP sensor is dirty???

Posted: Tue Mar 16, 2010 5:44 am
by _Mozz_
nunoctr wrote:yes. the 91% is in all cars. It's 100% but don't know why only read as high as that.

When you are above 960 map pressure it's at column 10, only near the end goes down that and goes to column 9. Clean your air filter and you can see a improvement

normal.
So, no one can run Colum 10 From top to bottom?

I have alot o areas where im above 960mBar and still colum 8/9.


Image

How can we improve MAP??

Regards

Posted: Wed Mar 17, 2010 8:35 am
by Gernby
The MAP is measuring the absolute pressure inside the manifold. At WOT at low RPMs, this is just going to be whatever the outside barometric pressure is. This changes constantly, and is also effected by altitude. If you drive up on a mountain, the MAP will go down. If you go down in a valley, the MAP will go up. MAP might be higher on Tuesday than it is on Friday, just due to weather.

Basically, the MAP at low RPMs has nothing to do with the TB. The only thing that you would hope to see different is at high RPMs where the stock TB might not flow as well as a larger bore.