currently reading A graham bell's book on forced induction and it gives a nice explanation of the 959 twin turbo set up and some 944 turbo background...that..well....may not be so accurate. but you guys will be able to know better than I. also says that porsche tested a 944 S with a supercharger and a turbo to compare. ill scan that as well. they say the turbo took 10 sec to spool to 8 psi. wow have times changed.

 

...

 

....

 

i think the turbo came out in '86. and it never had mechanical injection. unless they are talking about the prototype and earlier porsches.

 

inserts. i also thought that the 944t had only one knock sensor. at the most two. how does it know which cylinders are knocking?

 

porsche discovered.......that old turbos spool slow!

 

this is it. if you guys want i can put other interesting stuff i find.

 

Could you please get me the title of the book. I too would like to read it.

Thanks!

Tom

 

page51 obviously has a typo;

(in 1989 this increased to 274hp and 258lb/ft.)

should read;

(in 1989 this increased to 247hp and 258lb/ft.)

 

Very nice, I like how in maximum boost, Corky Bell talks about
Porsche being serious turbo guys, it briefly talks about the staggered trubo set up in the 959

 

The turbo ecu could possibly determine which cylinder was knocking by crank position. Knock takes place over like 25 degrees of crank rotation, and each cylinder only fires once every 720, so if it keeps track of where the crankshaft is it could figure out which cylinder knocks.

I have seen actual Porsche literature (upfixin) say that the 951 has individual knock detection capability, but nobody who has looked at the code has confirmed this.

Maybe TT will chime in, I bet he is the only one who truly knows.

One thing is definately not true, it says that the DME will enrich the mixture when knock is detected, but there is no way to do this when fuel does not travel through the KLR at any point and there is no input for knock on the dme. There is however a knock yes/no line coming out of the KLR that is not used, maybe porsche had this hooked up to the dme in place of the country switch or something at some development point, who knows.

Anyway, keep the scans coming, interesting.

 

oh. thanks for that bit of info mark. i never thought about the position. so it would only retard 2 cylinders instead of all 4. and if it used two on each side of the block. it could distinguish even further correct?

the title of the book is

forced induction performance tuning
a practical guide to supercharging and turbocharging.
by: A graham bell.

i like this book better than corky's. even if this guy LOVES superchargers. he says trubocharging a street car is pointless in his opinion. i think andy944 told me this book was written sometime in the 80's. but mine says 2002. so i think this one is a revision or something to include modern technology.

there is a freeking cool way to get rid of turbo lag that he talks about.
ill scan that in a little bit. instead of retarding timing to ignite gases on there way out. it is like a rev limiter that doesnt ignite the mixture for each cylinder once every 2-4 revolutions. so it acts as a rev limit while letting gas/air into exhaust to ignite. and since it doesnt ignite in the cylinder, its cooler and easier on the turbine. and since its a revlimiter. it allows full throttle shifts and keeps boost way up so when you get in gear and drop the clutch, your off!

 

oh. typo's! you think I speel bad. you havent seen ANYTHING!

the last book i read. how to tune and modify engine management systems (also JAM PACKED with sweet info) had SO many spelling errors i had to question if the book EVER went though the hands of an editor.
this one also has quite a few. and corky's had a couple as well.

heres a pic of all the books i have.

 

I cant wait to read the four stroke permormance book. maybe we can finnaly settle this NA power argument once and for all!

 

the are 1985 944 turbos... in europe.
~Eyal