TurboEF9

Mr. Davis, sir, quick question?

Which GMs do we get these MAP sensors from?

I've seen them advertised on eBay for ~$70, but it never specifys what vehicles they come from.

Chacko

I can't remember where I got mine it was through some GM Parts dealership and it only cost about $49 shipped with warranty. ( I think I got the part number from hondatas website and looked it up)

rextec

highjacked j/k
can you point me in the right direction for tuning GHD with a 2 bar map sensor?
thanks

leed

Syclones/Typhoons and the odd-ball Turbo Firebird had the 3bars. Any other force-fed GM product had the 2bar.

(Grand Nationals had 2bars if Im not mistaken)

turboteener

If the limitations to boost are that the stock map can't handle the range of the 3 bar MAP sensor, why can't we just change the size and resolution of the stock tables. I beleive I read somewhere that the stock tables are like 15x71 ( I am not all that program language literate yet, so that may be wrong) Can we not just come up with a table that is bigger or can handle the range? I realize Mike and others are working on a combination of maps but what about just using one big map? Would the map get so big the processor couldn't keep up with real time engine operation? Right now scaling is causing some problems, so why not try a different way?

88crxSi

this is just a guess. but i bet that the ecu is only programmed to look up tables in the 15x71 range and wont reconize the larger tables.

TurboEF9

Great question! I'm happy to see someone taking this a bit further. The stock map table size is 15x17. The reason you can't go any bigger? 8 bit math. The stock fuel interpolation routine looks up 8 bit, which is 1 byte, values from the fuel table, and stores that in a variable. Well, long assembly reason asside, the highest number oyu can get in 8 bit math is 0xFF.. sooo.. 15x17 = ? Correct.. 0xFF.

rextec

can anyone give me a simple answer to the original question?
will i NEED zdyne or i there an alternate way to run 14-15psi without the ecu freaking out.
thanks

zac

If you need 14-15psi right now, then yes, you need to look at commercial standalone systems (Zdyne) for management. If you can wait a few months, GHD should support it.

Clear?

turboteener

If 8bit math is the limitation for the size of the look up tables, could you change out the chip that handles that math to something faster? or would that shoot the whole ECU project?