IDM

Do I need to replace my map sensor for 13 psi?

I am currently on 7.5 psi and think I have the stock one.

Thanks guys.

Milan

Yes....you want the barometric pressure sensor from a Cobalt SS (if you want 2 bar)

IDM

What's the stock sensor good for

robert miller

If you have the stock yes you will need the 2 bar good up to 15 psi then the 3 bar....Robert

BLOWNBLUEZ06

It's good for up to 105kPa or .725psi of boost (the other 100 is vacuum).

IDM

So if my car is boosting at 7.5 psi I must already have it installed?

Can I check what's there with hp tuners?

pewter99

not necessarily...I am running 8.5 with a stock MAF....I need a 2 bar to really getthings right and turn up the boost a bit

BLOWNBLUEZ06

What Pewter said.

Many MAF tuned cars are running stock MAPs. How? The car is tuned to add fuel through a multiplier table that kicks in at a certain throttle position and your MAF is based on how much air is flowing through it and adjusted accordingly.

IDM

Thanks Brett But I definitely need a 2 bar if I want to do 10psi plus correctly with a maf?

pewter99

yes if you do a search in this section there is a ton of stuff about the 2 bar...I suspect even more in the tuning section...a 2 bar is next on my list of things to do....right now getting the car back is #1

Mike04

You don't have to do a 2 bar but it is a good idea as long as you have a tuner who is comfortable switching the car to a 2 bar OS and tuning it.

BLOWNBLUEZ06

Not definitely. There's some tricks to scale the MAF back if you want to keep it. The problem with going 2-bar is that many tuners lack experience with it and it can be very time consuming to get all of the driveability stuff properly worked out. Many capable tuners don't have or aren't willing to spend the time to dial in all of the tables properly.

pewter99

truth...you need someone who is going to spend the time

IDM

Thanks for the hookup on the shop!

I may have them tune it or Mike Norris.

You need a 2 bar for speed density for sure then right since you don't use the maf?

0Mike@NorrisMotorsports

We have been tuning SC'd C5's for years on stock MAP's and MAF's for a long time and have even done 800+ at the tires with such. This was before 2 Bar MAP's were talked about and we worked through the problems. It was not the correct way to do it but it worked.

The 2 Bar MAP I use on C5 Vettes is a GM 12615136 and works great up to 15 PSI and I would just keep the MAF for better driveability. It does take a while to get through everything and therefore costs more to tune, but it is nice to have at least a base line tune from a few cars here to have a good start.

Hope this helps.

Mike Norris

Corvette-Chris

It's been my experience that a SD tune has better drivability characteristics than a MAF tune. So much so that it was "night and day" difference.

Its Bruce

http://forums.corvetteforum.com/c5-f...-maf-tune.html

Robert 2000

My car is much better speed density than before. I have the cobalt sensor and my tuner spent quite a while getting everything just right

0Mike@NorrisMotorsports

There are different opinions on this for sure and I still prefer a MAF for a daily driver. The only time I have seen an issue is with one of two things with a MAF tune on an SC'd car.

First, someone did not properly calibrate the MAF.

Second, the BOV was too close to the MAF and causing a lot of turbulence in the MAF.

I see the second issue with the BOV a lot as folks like to mount a BOV up high to show it off. If it is within 10-12 inches of the MAF it can skew it terribly, especially if it has no screen or is a blade style MAF. I just had to changeover a 2002 TA to SD for this very reason. The idle was crazy erratic (as well as the MAF readings) and the BOV was 6 inches in front of the MAF. While it was sitting there idling we pulled the boost/vacuum reference off the BOV to close it and the idle (and MAF readings) smoothed right out.

Again, a few ways to skin this cat for sure.

Mike Norris

Zeus-of-Boost

So what would you guys suggest for a 408 and d1-sc ? Swap to 2bar, 3bar, or stick to Maf ? not worried about max hp just drivability and reliability.