Low VEC MAP reading for 10lb Roe

[mnviper]

I have a Roe supercharger with 10lb pulley on a mostly stock engine (1.7 rockers, headers, exhaust, W/M). I tried logging a third gear pull yesterday and was surprised to find that the internal MAP reading on the VEC3 showed a max of only 6lbs of boost. This has me concerned that there is an issue with the supercharger system.
I was wondering if anyone out there with a similar setup could share their VEC boost measurements for comparison. Thanks.

 

[plumcrazy]

im sorry, you're not a member here, i cant help you or give you any pointers.....


J/K of course

 

[Steve 00RT/10]

Seems low. You might want to check the sensor settings in the log settings area. My boost signal is set at MPX_US_3.

My 5 pounder with the same set up -- no W/M -- sees 7+ with the boost creep......just looking quick at a couple logs. The roller rockers make it breathe a little better, reducing a liitle pressure (and heat)

My 5 pounder with no 1.7s has seen a little over 9 pounds with boost creep.

Steve

 

[DAMN YANKEE]

It is low...even for a non member.....Don't mind Plum, he is good for a dose in an hour and we can take the jacket back off.

Here is my 5lb unit, without W/M (just like Steve's) in fact Steve and my car are the same year.

Tops out at 9.26 lbs and got to your 6 lbs by 3.5k RPM....

Used Unit? From where? Been rebuilt? Who installed?

 

[DAMN YANKEE]

Hello...earth to mnviper....come in please....are you still out there.....

Used Unit? From where? Been rebuilt? Who installed?

 

[mnviper]

DY, Thanks for the response. This is a new Roe unit installed last fall. I wanted to confirm that this is an abnormally low number for an on-road pull with a 10lb pulley before I pursued it further. I discussed with my tuner today, he gave me some some things to check on before we point the finger at the blower (belt tension, etc). BTW, your posts on logging and the tutorial have been quite helpful in getting the VEC software setup.

 

[BOTTLEFED]

my readings are low (8# max) on my Roe10# and Sean says it is because I'm running rich
he sent me a new prog.
I'll try it out tomorrow

 

[DAMN YANKEE]

Your in good hands, if you have widebands and can log, send up some logs.

 

[v10kingsnake]

my readings are low (8# max) on my Roe10# and Sean says it is because I'm running rich
he sent me a new prog.
I'll try it out tomorrow

I never really understood the "mail order" tune adjustment thing. You know, or should know that even with a slight tweak from Sean that the tune still isnt going to be as precise as taking the car to a dyno under the eyes of someone like Sean to tweak the tune to fit your car based on what the dyno is showing. Why spend all that money for horsepower you know your not optimizing. Just my .02

 

[Steve 00RT/10]

I never really understood the "mail order" tune adjustment thing. You know, or should know that even with a slight tweak from Sean that the tune still isnt going to be as precise as taking the car to a dyno under the eyes of someone like Sean to tweak the tune to fit your car based on what the dyno is showing. Why spend all that money for horsepower you know your not optimizing. Just my .02

I agree somewhat with the mail order comment, but unless you're taking the car to Sean, or other good tuner guy, who can knowingly monkey with spark as well....the best way to tune AFR is with 'on the road' log runs. ....Just going to the local dyno to tune AFR is not real world running and can't produce as good an overall result. As for spark, except for bragging rights, there probably isn't enough HP to count as far as the car being a lot faster.....unless you want to run on the ragged edge of detonation

Steve

 

[BOTTLEFED]

I was running 7-8 AFRs so that is why Sean had to change the tune I got from him originally
I just needed something a little closer to work with for my own tuning

 

[mnviper]

I'm curious as to how the rich A/F can drop the boost readings. Is this due to the cooling effect of the extra fuel?

 

[BOTTLEFED]

ask Sean
thats just what he told me