Ducman82

So i am in the process of adding knock sensors to my Mega Squirt set up for better tuning and for the inevitability of me adding a mid mount turbo next year...

but i have hit a snag.. i have the spider intake so the U for the throttle body bolts to the rear most "valley plug", and the front most plug is just an hex allen plug... SO.... i was going to add two sensors like you would have on the late model cars.

i know i can drill out that plug and tap it for a bolt... but what about the other one? where could i mount it?

atb

Post pics, I'm going to be running wires to do this very soon. I was resigned to running a single sensor in the middle hole, but now I'm curious how you are going to wire the pair.

Ducman82

ya, right now I'm thinking i might be able to run one sensor up front... maybe see if i can squeeze one in the middle. the only other option i can think of is some how bold them the sides of the block, just not sure where.

i ordered up the DB15 connector for the MS box for adding the sensors, turns out i had one already... that will teach me to look before ordering.

how hard are the valley plugs to get out? anyone have an extra one that is already threaded?

John Speake

Porken added one towards the front on his 85/86....... when developing his chips.

Vilhuer

I'm building S4 engine with S3 intake and S4 electrics for friends race car. Idea behind it is hp/weight based class structure in local club races. Can't have too much hp or it gets bumped to class where hp has to be 500+ to be competitive. Need to keep hp at stock level and idea is to make as much tq as possible instead. Solution is to move power to lower revs by using S3 stuff. Anyway, it has same problem. S3 U-bend under the intake is mounter to rear sensor mounting point and two other place on block. Plan is to cut that mount of, build some other support for it and put sensor in usual place. Other option is to replace that U piece with some hose. Its good to have sensor in normal place as it's right in the middle of four rearmost cylinders. Which is obviously best place for it and where factory computer expects it to be. In another location system might not work as planned.

Ducman82

that is not out of the realm of possibilities, but i would hate to cut up "euro" parts. a custom U would not be to hard to make.

PorKen

S4 block plugs - unfortunately they have to come from a dead S4 block.

Carl used to make them from brass. Maybe he has some left over or can make more.

OD 14x1.5 x ~13, ID 8x1.25 x ~16




I've thought once or twice about converting my S3 to use S4 brains. Besides remapping for the cams, the EZK needs to have the code changed so that it uses just one knock sensor. (The EZK cycles through its inputs using a switch chip to select the input which is sampled by one D/A converter.)

Ducman82

Sent some emails..... Anyone got a dead block that has the plugs? :-)

yardpro

why cant you just take a regular bolt and drill and tap it?
seems like that would not be too hard to make, even if you had to have a machine shop fab it....

WallyP

As Erkka says, you have to use the knock sensors in the locations expected by the control unit that you are using. The 928 S4 unit uses time-of-flight on the signals to determine which cylinder is detonating. Moving a sensor will probably cause real problems.

If you are using another control unit, you will need to determine what the requirements are...

Ducman82

thankfully I'm using Mega squirt, and double thankfully Colin already has settings figured out for the knock sensors...

atb

Do you have connectors to make pig tails or are you cutting the ends off the stock sensors?

Ducman82

ROger is mailing me the 3 pin connectors (harness side) so i can wire in using stock (un molested) sensors.

Ducman82

any one know what the pins are for the stock sensor? i need to add the harness connectors but not sure what 1-2-3 are. from what i can find 1 is signal, but what number is ground and shield ?

Ducman82

think i found it.
pins

1-ground
2-signal
3-shield