black top speed sensor fix???

[gasman]

ive recently put a black top into my car and it goes fine and all but the rev cut is only at 7600 and stock is 8200 from what i heard.

what are my options for putting in a "device" to feed a siginal back to the ecu so that the rev cut is bumped back up to its natural habitat?

im trying to avoid the magnetic reed switch option as i dont want to be strapping magnets to my drive shafts that would eventuall fly off and wires becoming tangled with the shafts etc.

cheers

[Bling]

afaik stock cut is 7800, are you just reading it off the tacho? if so that might be cutting at the correct point

[Logan]

What car you put it in? You maybe find that your factory tacho is just inaccruate, well thats what it was in my case, i hit the rev limiter at about 7800 on the tacho but on the dyno was more like 82 iirc

[85AW20v]

I had the same sort of thing when I put the silvertop and E51 g/box into the MR2. It might sound stupid but I picked up the extra 500rpm when I changed back to the C52 box - and that was the only change I made!! The speedo wasn't working with the E51 but was with the C52. Rev cut went up to 8k. Go figure that one out......

[MetalupYoAss]

who knows how to build that timer circuit to fool the ecu?

[KinLoud]

What car do you have? EFI or carby? What gearbox do you run?
Revcut for a silvertop is 8200rpm? So blacktop would be similar.

I put a gen 3 3SGE into my 1983 Carina racecar.
All I did was connect the ecu speedo wire up to the reed switch in the back of the speedo. Most efi cars have some sort of speed input to the computer - earlier ones had a reed switch next to the magnetic coupling that drives the speedo needle from the speedo cable. Later ones (like the car my 3sge came out of) have an electronic speedo and so the reed switch setup (or similar) lives in the speedo sender that bolts directly into the gearbox.

Ken
Ham
021 408 863

[gasman]

the car was a ae92 carby and i had a look at the back of the dash when i was putting it in for the speed sensor outputs but they were non existent.
gear box is a c52 i think off a 16v 4age, crunchy as hell in secon and third by the way. and for some reason even tho my old box on the old 4af was also a c52 it revs about 3200 when im going 100 in top gear when it used to rev 3000 in top gear.

[AceSniper]

4af vs 4age box's even tho both c52's the final diff ratio changes

[KinLoud]

What speedo setup do you have now? Cable or electronic?
Your 4age C52 will have/would have had a speed sensor in it. If it still does just take your speed signal from it.
Or maybe change the dash to a 4age dash if the loom will plug into it.

Ken
Ham
021 408 863