Greetings fellow boosters! Correction!, I'm not actually creating any boost yet, so I'm not in your ranks yet, but I want to be. I created this thread to chronicle my adventure of boosting my 1985 928 S 5 Speed car.
The hope is that all the knowledgeable folks that have been down the road I'm travelling can chime in and share their wisdom and all the do's and don'ts of boosting a 928.
To learn the back story about the car and it's general rehabilitation please read this thread:
About the Turbo kit. Built and installed by Mark Robinson in Austin Texas.
See MAF harness and Turbo Design Documents (Currently 3 page pdf Will scan again on a plotter at work to make it 1 page)
The turbo kit is made of of the following components:
Mid mounted Precision Billet 62mm with a T04 hot housing with a .96AR
A new stainless still exhaust with a CAT delete.
30 LB injectors
Wide band O2.
Boost controller (Yet to be installed)
Fuel rail pressure gauge.
Oil scavenge pump (Cheap and loud, I'm replacing with a gear driven pump)
Mark was also hired to perform a top end refresh, new plugs, wires distributors rotor . Temp II was replaced as was normal band 02.
Car would start and run rough and when hot wouldn't start again.
AFR was at 10-12
MAF checked out at 382
idle is at 1100
Timing was retarded to 14deg
After some powder coat removal on the WB AFR is 14.9-15.00 but bounces to max on occasion. Starts when warm now.
Paid for Mark to tune on dyno to 450 - 500 HP and have non det chips put in.
Dyno and tuning did not happen. The specs on the chips are as follows "Taken from a chat with Mark " " Just the EZK chip was designed by me with Boostlogic and then mapped and burned by John specifically for a turbocharged (not supercharged) 928S 32v 85-86.
Marks suggestions on tuning "The car won't feel "strong" until the air-fuels are normal on the Wideband: you wanna see 11.8-12.0 on-boost. Readings while cruising should be 14.7-ish with O2 corrections"
you can "trim" the air/fuel via an adjustable fuel pressure regulator, to ensure you're at about 12:1 A/F ratio while on-boost.
"You should not be able to completely tune without a SharkTuner: which I once had access to & the interface for (came damaged from Speake). But fuel trimming while on-boost can be done by adjusting the fuel pressure up/down as-needed indicative of your measured AF ratio while on the dyno (or while driving). Start off in 2nd gear and make your first adjustment: if it goes above 13.5; stop your run and enrichen & then try again. once you have 2nd gear mastered, then go for 3rd: closely watching the AF gauge. while in 3rd, if it goes richer than 13.3, stop the run and enriching (increase fuel pressure by screwing the set-screw in: 1/4 turn = 1psi fuel pressure increase). Once 3rd is mastered, then try 4th if you dare venture that fast "
I was put in touch with a gentlemen named Pele , who has the same MY ,Engine 5spd trans and the same kit by Mark . He has a Shark tuner and has spent several years tuning his car. I paid him to burn me a set of chips and we believe that if I make some adjustments to my kit, to match his setup, then I'll be much closer that I am now. I have also reach out to John Speake and will purchase my own Shark tuner.
Here is what I have to do to get my kit to match Pele's kit add a an 1987 MY FPR.
Move the MAF from the rear of the car to its original position.
Install the chipset for EZK and FH.
Set the MAF CO and Idle.
Find an intercooler
Install the new Scavenge pump "Can be done later"
Install the Boost Controller
Here are some videos of the turbo.