OK, so I just finished an SR20 swap into my buddies FC, runs great, everything functions the way it should except for the tach.

I kinda figured the tach output from the SR coils wouldn't match up with the input for the stock FC tach.
I put a timing light on it and when the engine revs at around 2000rpm the tach shows 500 rpm.

Any idea on how I could correct this?

 

the FC tach runs off of a 4 cylinder ignition pulse, and doing the 20B swap you either need an ECU that can do a 4 cylinder tach output, or this little box http://www.dakotadigital.com/index.c...rod/prd127.htm

i don't know anything about the SR20, but it would be weird if it didn't have a 4 cylinder out somewhere.

ive used that dakota digital box, it works

 

+1 on the dakota digital, most ls1 v8er use this

 

Dang, I was hoping not to have to order any more parts for this car haha.

Also strange that the FC tach uses 4cyl ign pulse but does not like the SR signal.....hmmm

 

yeah i know, my friend did an ls1 into his volvo, which is where that engine belongs BTW; car is AWESOME, and the ls1 ecu spits out a 4 cylinder signal, and the volvo cluster also is 4 cylinder, even though the volvo was a 6 from the factory. it must be an obd2 thing?