ive recently installed the fedi imperial gauge in replacement of the stock MR gauges.

there were big difference between the two...

the stock one read 1.5 kg/cm2 which is 21.3psi

and when i hooked up the defi one on same boost line it read 25psi
so i was like holy ****~! and turned down the boost to 22.

i thought it was just me but my friend with different series defi gauge did the same thing.

the thing is ive been running with the stock gauge till recently 1 1/2 yr with 25psi and had no problems. and i was wondering if the defi gauge is accurate.

ive heard that the stock ones are pretty accurate too.

what you guys think?

 

Test the guage. Either hook it up to a compressor or go on the dyno and log boost. That the only real way to see

 

that is intresting... is everything connected right... if so... it's time for me to buy some defi's... lmao..

 

everything is connected right. i triple checked...

and besides it used the same lines that was there before when i used the stock ones...

i just tapped the electrical wires for power.

 

my defi d series reads about 3 psi higher than my gm 3 bar map at full boost. Vacume and low boost they are about equal. I think the defi (and many others) read higher under higher boost.

 

im thinkin about going back to the previous boost which is 25 ish on the defi one.

i mean i had no problems with running 25psi for year and half... (according to defi)

i thought defi's are more accurate thats the reason i got them but i guess i was wrong.

 

I'm had a similar situation when I went from the stock MR gauges to the AEM Digital gauges.
My AEM boost gauge indicates that I peak at about 24psi. It would appear that you are maxing out on the stock gauge and the defi is just able to read beyond what the stock gauge can.

My 2c.

 

My MBC is set for 21 psi and my stock gauge is 1 cm away from the end, but my defi reads 24 psi when I am boosting. I believe when you T bolt the wires, it effects something, but I could be wrong.

 

wow your lucky running 25psi for that long didnt mess anything up man...

 

Are you TUNED for that psi?

I'm not trying to flame you, but you shouldn't be running boost above the factory settings if you haven't been tuned.

BTW, very few gauges are perfectly acurate whether its defi, factory, or whatever. What matters is if they are consistent. You need to get tuned or run some sort of data logger and find out what psi the ecu is seeing and compare it to the guage. Its not uncommon for the tuners to see 22 psi while dyno'ing and road testing and the guages be off by 2-3 psi in one direction or the other. Remember, as long as you know your guage is off by 2 psi, and its consistantly off by 2 psi your fine... or whatever it is.

The only guage I have seen that is consistently near perfect in accuracy is the Aem Tru-boost.

 

Joey, that gauge is a bit off as we found while tuning. I've heard that the Defi gauges are often off by about 2 psi. My stock gauge is super close to my JDM MAP logs, which also seems to be in line with the experience of others. I'm surprised that people still shell out the cash for those gauges when it's so common for them to be WAY off ...

 

My defi reads a few PSI high.