Is the best location for the front 02s in the log manifold before the turbo or in the downpipe after the turbo? Would there be a difference in readings across the turbo? Also, is it very important to read both banks with the widebands for tuning? This will be a forged 408 at about 9.5:1 CR with a Turbonetics Super T-76 or similar turbo. Does it sound like I am on the right track? I have been making extensive use of the search feature, and was just wondering about some of my specifics. If anyone has any suggestions for a single turbo set-up I would be appreciative.
Thank you for your time and knowledge

 

the sensor it usualy in the down pipe. sometimes right near the turbo and sometimes a couple of feet away.

reading one bank is fine, if your runing a single with the sensor in the down pipe then you will be reading both banks.

the turbo selection really depends on your power goals. on a motor as big as a 408 the t76 might not make as much hp up top as you would think. it will spool up prety fast and be fun to drive

 

I would like to get 650-700 rwhp, does that sound possible with a t-76? I don't have any restrictions on which turbo I use, so if there is anything better suited for the 408 I will definetly check it out. I was also wondering if I will need a new A/C dryer if I remove the hose to re-locate it?

 

My driver's side o2 is in the crossover pipe. The Passenger side is in the downpipe, so it reads both sides. It isn't really ideal, but it still works pretty well.

I don't think you need the 408 to reach your goals, but it would be fun to drive. I just built my 6.0l 30 over with eagle rods and Diamond pistons. It should be more than strong enough to get the power levels you want. It isn't there yet, but once I have everything worked out it shouldn't be too far off.

 

As far as the AC goes CMS recommends taking it to an AC shop. But, I just put a big wrench on mine and yanked it until it was out of the way. I expected it to leak, but so far I haven't had any problems.

 

Thats good that you were able to move the A/C line. I was curious about the a/c because I heard that if you open the system the reciever/dryer will absorb all of the moisture in the outside air, as well as the system loosing its vacuum. I would guess that I *could* need a new dryer if that happened, but I'm not sure what would happen because I have never opened a system to re-use before. A friend of mine has an a/c charging set-up at his shop, I'll give him a call and see if he has any suggestions for disconnecting the line to get a new one made.

 

Its best to just get another line from a junker and take it to an AC shop and have them cut the ends and reweld the correct angles you want back on and lengthen the hose to 2 feet total. This will allow you to lay it across the motor to get it out of the way. Cost me $50.00 to get mine done. You dont want your A/C system open to the elements for any longer than you have to have it. You will need to suck the R134 out of your system first, then replace the hose, then put the system under a vaccume to make sure it does not have any leaks (holds vaccume) then pump your R134 back into it. Be sure to use new o-ring seals on both line ends and coat them in that A/C oil before installation....

 

I will start looking around for a spare line, thanks for the tips.

Another question that popped up about turbo ls1's, was a potential lean issue with cylinders 3, 5, and 7 using a factory intake manifold (especially ls1 or ls6). Is this anything to be concerned about? (I plan on keeping the stock truck manifold on the 408)
Thanks again for the straight up answers, they are much appreciated!

 

Unless you want to do quite a bit of fab work you are stuck with the stock truck intake... I have a thread about this over here https://www.performancetrucks.net/fo...d.php?t=368838