OK, I have a 91 3.1L/Auto Firebird, and I am looking to do an LS1/T56 Swap...

What do you have to do about the gas tank/fuel system?

How can you get the SpeedO/Tach to be accurate?

Thanks!

 

1) Upgraded Fuel Pump, New Fuel lines in Engine Bay, and fuel pressure regulator

2) Speedo just needs to be re-calibrated, while IIRC correctly, you'll need a Dakota Digital box to make the tach work....

I'm going aftermarket on the tach, because i refuse to spend money on making stock tach work....

 

He wont need a dakota digital to use the Speedo if he has a 91. It already uses VSS and as long as he uses the LS1 PCm and T-56, nothing needs to be done.

For the speedo and tach you'll need to switch your gauge cluster to a v8 cluster. No way around it unless you solder a chip from a v8 cluster on your v6 one. You can re-calibrate the speedometer settings inside the LS1 PCM.

Not sure on the fuel pump. If a TPI fuel pump works with a LS1. No need to upgrade considering the 91-92 v6's came with the TPI pump.

 

Well, except of course for piece of mind on the fuel pump.

 

Yeah that's what i meant, the speedo doesn't need any sort of adjustment (if it's a V8 cluster), however the tach won't continue working if you keep the 91-92 style gauges, and to the best of my knowledge, the only way to get it to work is with a digital box....Mine only reads about 55-60% of what the actual RPM's are....

 

V8....V6....doesn't matter, speedo is always the same. VSS just counts the revolutions on the driveshaft. If your tach is off, im not sure on the ls1 as far as the tach since it uses 8 coil packs, so it probably gets it from the pcm. But if it is possible to get the signal from the ground on one of coils it may work. I am not sure since the LS1 uses a different ignition system. Im sure someone will chime in and let us know.

 

the dakota digital convertor will let you run cruise control and control your speedo

and its only 70$.. pretty much the cheapest thing in the swap

i bought the convertor box from baker electronics.. it does everything you need and the tach.. cant beat it

 

I wouldn't recommend using a standard TPI fuel pump, making 58psi would give it a short and painful life...they're rated in the 43-48psi range.

Walbro 340 pump, 255 liters/hour and easily makes the 58psi you need.

 

Does anyone have a fully functioning stock tach after swapping in an LS1?

 

Thanks for the help guys! So, If I just buy that Dakota Box, I can just keep my V6 Cluster?

Also, I know about the fuel lines and a new pump, but what about the gas tank? Can I keep the stocker???

Thanks:cheers:

 

Yeah

However if you swap in a 4th Gen tank, you can already will have a stock 4th gen fuel pump in there that you can use for the swap.....

 

I do basically I have a 3/2 frequency divider in between the LS1 signal and my tach(v6) (I am off maybe by 50-100RPM max)..but it seems clean

4 cyl signal -> 6cyl tach = 6/4 = 3/2 divider

BTW guys I don't think a stock v8 tach will work with the LS1 ...stock v8 tachs are 8cyl signal line and the LS1 outputs a 4cyl signal (so unless you do a *2 of the signal coming in from the LS1 PCM...you will read 1/2 of the RPM...)

as far as the speedo goes I am getting a 5" Autometer speedo and I am going to do some hacking to get it to fit in the dash...I do not like the idea of having gauges hanging out

 

I do, but dont have a clue how Hawks did it

 

http://cgi.ebay.com/ebaymotors/ws/eB...tem=7917447862

thats what ya need for the tach



for the gas tank i just gotta to the math to figure out how to make the 30-120 ohm i think ls1 tank work with the 0-90 stock gauge

 

http://cgi.ebay.com/ebaymotors/ws/eB...&category=6763

This is what I got..actually it includes the part above inside and also has a bunch of other stuff like VATS, O2, etc ...plus Neil is an excellent guy when it comes to answering questions and stuff, for the most part this unit works like a charm and is extremely easy to install, the price is way cheaper than trying to get all that seperately (caspers o2 sensor is about 100 bucks by itself.)