I was thinking the other day( Scary isn't it) that if s speed density system reads off the vacume in the intake then how does it funcion with a super charger. It seem like it would never see any vacume because the Supercharger is pressurizing the the intake track. Anyone doing this? DO you have to change the computer or what? Just a thought because I am running MAF so it doesn't really do much for me other than curiosity.

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86 Trans Am 355 TPI Rebuilt 700R4 with Corvette servo, modified valve body, and a B&M Torque Converter (2000 rpm stall w/ lock up), 87 350 block bored .30 with new crank, bearings, rings, and magnafluxed rods. Reworked 305 heads with 3-angle valve job. Added in the rebuild was an SLP TPI cam, BBK 58mm Throttle Body,SVO 24# injectors,MSD 6A, Hypertech Power Coil, 1.5 Crane roller tipped rocker arms, SLP Intake Runners and Port matching in upper intake including fully ported plenum, TPIS adjustable fuel pressure regulator @ 46psi, Hooker shorty style headers w/ Thermotech heat wrapping, Custom 3” exhaust with Flowmaster muffler and chrome quad tips, Hypertech Thermomaster Computer chip, K&N open element cone filter on modified MAF per TPIS specs, MSD Wires, removal of A/C hardware and a 1LE firewall cover installed. Also there has been a PST front suspension kit with Hotchkis strut tower brace
http://geocities.com/SunsetStrip/Garage/9548/kyle.html

Kills:
95 Talon TSI, 96 Probe GT, 91 T/A L98, 89 RS, 86 Mustang GT, 88 Mustang LX 5.0, 92 Thunderbird V8. couple or ricers that I think were Civics or Preludes not sure what year, 95 Celica GT-S, 94 Chevy 1/4 ton 350, one of those NASCAR F150's ..... **** on Monkie
SOON TO BE A SUPER CHARGED TURBO WITH NOS ON A 500000 CU. IN engine

 

You are correct. A naturally aspirated engine requires a 1bar MAP sensor which reads from -15psi to 0psi (atmosphere).

If you are running up to 15 pounds of boost you need a 2bar MAP sensor which reads from -15psi to +15psi.

If you are running from 15 to 30 pounds of boost you need a 3bar MAP sensor which reads from -15psi to +30psi.

What you will sacrifice with the 2 and 3 bar sensors is resolution, so you would never want to run a 3bar sensor on a naturally aspirated engine.

You would also have to program the new fuel/spark requirements with either a programmable ecu (like Accel/DFI) or by burning a custom prom for the GM ecm.

[This message has been edited by TunedPort350 (edited December 26, 2000).]

 

There are a few guys running super charged speed density setups with no problems. A new PROM? Well that goes without saying It's a freaking Supercharger you're putting on! Not an airfoil!

Your best bet would be to take a recorded run on a Diacom and send it to the person burning your chip. That's about as custom as it gets.

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91 Formula
305 TPI 5speed
1LE/G92/WS6
Custom cold air intake w/K&N, SLP airfoil, ported plenum, TB coolant bypass,Crane AFPR (47psi),94 octane,Crane Extruded Alum. 1.6 full roller rockers, Timing set from 4*BTDC to 10*BTDC,MSD6AL, Holley 9mm Annihilator Laser shot 50 wires, Ac Delco cap,rotor and plugs, Bosch O2sensor, SLP 1 5/8 headers,SLP catback,3:73s,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.
Street legal with stock throttle body, runners,intake manifold,cam, and heads. Coming next..9# Procharger!

 

i've been running the stock prom in my car since it was new and still do now.as for the 2 bar you cant just add one to your factory computer it wont work right.granted next spring when i get a new cam and 30 lb injecters it will need a custem chip right now it dosent run too bad(i am by no means saying that it is running perfect)the car also has afr heads.
pete

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1990 Trans Am,350 TPI(L98),WS6suspension ,bridgestone RE71's /245/45/zr16
paxton supercharger, alston sfc's,msd 6AL-BTM,
8.5 superconductor wires SLP 1-3/4 headers,duel cats,3"slp exaust, lakewood LCA's,T.B.Bypass
160 degree stat,alum driveshaft,fiberglass wing, secret mods

"if you cant win fair CHEAT"

 

Some systems use a 2nd pressure regulator that bumps the fuel pressure a certain amount for every 1 psi increase in manifold pressure. They are adjustable, so you can dial it in without changing the PROM or other sensors.

89 Transam GTA, a few bolt ons

 

Thanks guys. I now know morer than the day before.

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86 Trans Am 355 TPI Rebuilt 700R4 with Corvette servo, modified valve body, and a B&M Torque Converter (2000 rpm stall w/ lock up), 87 350 block bored .30 with new crank, bearings, rings, and magnafluxed rods. Reworked 305 heads with 3-angle valve job. Added in the rebuild was an SLP TPI cam, BBK 58mm Throttle Body,SVO 24# injectors,MSD 6A, Hypertech Power Coil, 1.5 Crane roller tipped rocker arms, SLP Intake Runners and Port matching in upper intake including fully ported plenum, TPIS adjustable fuel pressure regulator @ 46psi, Hooker shorty style headers w/ Thermotech heat wrapping, Custom 3” exhaust with Flowmaster muffler and chrome quad tips, Hypertech Thermomaster Computer chip, K&N open element cone filter on modified MAF per TPIS specs, MSD Wires, removal of A/C hardware and a 1LE firewall cover installed. Also there has been a PST front suspension kit with Hotchkis strut tower brace
http://geocities.com/SunsetStrip/Garage/9548/kyle.html

Kills:
95 Talon TSI, 96 Probe GT, 91 T/A L98, 89 RS, 86 Mustang GT, 88 Mustang LX 5.0, 92 Thunderbird V8. couple or ricers that I think were Civics or Preludes not sure what year, 95 Celica GT-S, 94 Chevy 1/4 ton 350, one of those NASCAR F150's ..... **** on Monkie
SOON TO BE A SUPER CHARGED TURBO WITH NOS ON A 500000 CU. IN engine

 

The syclones came with a 2 bar SD ecm, and it is hac'd. There is an aftermarket option for even using a 3 bar MAP Sensor.
There are what are called FMUs (Fuel Management Units) that instead of raising the fuel pressure one PSI per PSI of boost can go 2 to 8 to one. So at 8:1 it raises th rail pressure 8 PSI per pound of boost.