Blower installed BUT????

[MY 85 GT]

Ok i have the powerdyne installed on my 87 GT speed density car BUT...i cant go into boost it falls flat on its face like your turning the key off...let up on the gas its ok...Hit the gas falls right on its face...I know i heard you have to use a check valve of something...I called vortech they say they still sell it..But will that really help does that stop this problem???

 

[RacEoHolic330]

Is your oil filler tube connected your throttle body? What size injectors are you running? Will it make any boost at all, or does it quit as soon as the boost gauge goes past 0? Do you have any tuning equipment. Supercharging and SD car can be tricky without a tune.

 

[MY 85 GT]

Is your oil filler tube connected your throttle body? What size injectors are you running? Will it make any boost at all, or does it quit as soon as the boost gauge goes past 0? Do you have any tuning equipment. Supercharging and SD car can be tricky without a tune.

No my oil filler tube has a smaller filter on it the TB is capped off...19lb injectors with an FMU calibrated 12:1 and a 190 lph fuel pump and an aeromotive afpr....And anything past 0 on the boost guage the car just falls dead flat like someone turned the key off let up on the gas it will drive like normal again...Hit the gas boom flat on its face again...No tuning equipment at all...I know Vortech sells a SD kit for these cars i know you can still but them to run a blower on a SD car im thinking of doing that now...buying the check valve kit they sell...hopefully that will help.

 

[RacEoHolic330]

I converted to mass air before I installed my blower, but I assume that check valve has something to do with the MAP sensor. I would guess that sensor doesn't take kindly to seeing boost at all, which would make sense because the MAP sensor uses manifold pressure (vacuum, not boost) to deterime the a/f ratio.

 

[Wildstringer]

When I had my 302 bored and stroked it ran like crap until I converted it to MAF. Do you have any other major mods? If not you may be experiencing the same problem.Speed density computers can not compensate for major changes

 

[2000xp8]

The problem is likely the map sensor.

Convert the car to mass air, it's not that expensive these days.
If you can afford a supercharger, you can afford mass air.

 

[MY 85 GT]

The problem is likely the map sensor.

Convert the car to mass air, it's not that expensive these days.
If you can afford a supercharger, you can afford mass air.

I want to see if i can make it work with Speed density the car has a Paxton sn93 when i bought it the blower was on that car is almost new the guy before ran the blower with speed denisty he had no problems..I took the car to the shop i use was going to go turbo..Sold the paxton and well My Dad got sick he needed to go back to work so i gave him my 90 GT to use...So i had the guy put the 87 back i got bored bought this blower installed it myself and now im having this problem I know the MAP cant see boost and im sure it had the check valve kit installed the guy took it off i guess when he re-did my car..Maybe someday i will go to MAF but now i dont feel like it the kit from vortech is 26.95 alot cheaper then going to MAF for me right now and if it work it will be good...LOL...if not then MAF it is...

 

[2000xp8]

The check valve should work.
It's just that the mass air setup monitors the intake of air, and when you are talking boost, any extra accuracy is always a welcome thing.

 

[sfcadams]

You just need the Vortech check valve and you should be good to go....

 

[oldfox]

anyway of disabling the supercharger and seeing if it shuts off when you
floor it? maybe it's something not related to boost.
just a thought

 

[MY 85 GT]

I have been driving the car now for 6 months with the blower on put the blower on this weekend took it out hit the gas once boom fell flat on its face just like ive read a Speed density car will do if boost hits the MAP sensor i guess its time to order the check valve kit from vortech...