Steve@C56

Hi,

Until now, i was rapping the PE table because i'm using the stock 1 bar MAP.

FYI, it's a LS1 block with full forged internal and a overspoon vorvech V3.SI with 8" and 3.125. Should shoot +15psi, but since it's a big cammed (less psi), long tube (less psi again) and 383 stroker (also less psi), not sure to hit +15psi

Can i gain some HP to go 2 or 3 bars ?

Should i choose 2 bars for have more step from 0kpa to 210kpa ?

For 3 bars, i find this : http://www.efisource.com/shop/ls1-st...ar-map-sensor/
It can be a good choice ?

Best regards

Chris Stewart

I ran a 2 bar to 17psi but eventually wanted more boost, and the 2 bar wasn't cutting it. I went with the old brick style 3 bar and has worked well.

PEETYZ

I run a 2.5 bar and it works great and came with good info

http://www.dedicatedmotorsports.com/product_p/25bms.htm

stevieturbo

The sensor will not make one bit of difference to power.

Always use a sensor that allows proper tuning and with headroom for safety.

Mike04

Sounds like 2 bar is all you really need, more steps is better. The 2.5 is the option I'd recommend. I'm running a 2.5 and am very happy with that. I got my 2.5 MAP from a tuner who goes by Dsteck on HPtuner forum several years ago.

Biggest thing is the tune/ tuner.

realcanuk

Use same one and it works well. Dsteck is now with Dedicated and it's the same sensor mentioned above.

BLOWNBLUEZ06@RKT Performance

Summing up what's already been said:

Tuning with a custom OS allows you to create values that are mathematically correct so that when you try and create histograms that compare desired AFR to yielded AFR, the table will get properly populated, making proper tuning easier. At a certain point, the MAF lacks the range needed to accomplish this, forcing the tuner to hack/"rape" the PE table to get the needed fueling which skews all the commanded AFR values. Proper fueling can be accomplished either way, but it's much easier to validate with a custom 2 or 3-bar OS and appropriate sensor.

ysb02

I just ordered the sensor you linked to to convert to a 3 bar HP Tuners OS. I've been tuning the stock OS failing the MAF. The resolution in the HP Tuners SD table will be the same (just copy my values over?) with just increased range in the VE table? My car is still mostly stock / NA.

C5Natie

I ran a 2 bar up to 18psi. I just got a GM 3 bar off a ZR1 since I'll be going up to 25psi. Holley makes a nice adapter harness if you need one to go from LS1/2 to LS3 type map

turboffr

I'm also using DSteck's 2.5 bar MAP and converted my OS to 3 bar using HP Tuners.