oliver foster

I just turned my fuel screw in 1 3/4 turns on my '85 crew with a NON I /Ced 12v.
I adjusted the idle and throttle rod and it runs great!
It jumped from 23 PSI max to 30 max, and it builds PSI quickly now.
The motor other than a Cooler Tubz was dead stock.

I have a stock 3 inch down pipe and a mandrel bent 3 inch pipe around the T-case.
After that I used a stainless 4 inch mandrel bent system [with a free flowing muffler] I had off a 2nd gen.
I am hoping to lower my exhaust a just a little as I can get 1300 and still slowly climbing on my pyro WOT on a hill cruising empty.

I don't tow with this truck so I am just looking at tuning it to run lightly loaded with just my camping gear and the family.

I was wondering if using a Diamond Eye 4 inch down pipe and 4 inch pipes around the T-case would lower my EGTs enough to make it worth while.

If I could lose about 100* at WOT it would be worth the $200 and time on my back swapping it in.

Anyone have before and after EGT #s after a similar exhaust swap?

Or I could just back out the fuel screw a 1/4 turn

oliver foster

Maybe about a 100*F drop is being too optimistic...

BILTIT

You might see 50f drop. Easiest to just turn out the fuel screw a little.

1972RedNeck

The exhaust dropped mine out 75 - 100 degrees. I had a 3" non mandrel bent system with a crushed spot though.

oliver foster

I read some exhaust systems, talking about 100-150F* drops at WOT.
I was guessing 50*-100F* was more likely, even more so as I am starting with half of a free flowing exhaust system in place already.
I will drive it around a little more first to decide if I can live with it where it is.
If it seems to get too hot I might just turn the fuel screw out a little bit for now.

cougar

I put one on my 91.5 a few years back hoping to drop the EGT some. Instead my engine lost power and had a huge turbo lag and smoked like crazy. I was unable to tune it completely out. A bigger turbo helped, but was never 100% happy with it. Some recent changes and a re tune finally got it to were I really like it.

oliver foster

Yikes, lost power and smoked more....
I'll just turn down the fuel screw just a touch.
It is running great other than about 100F* hotter than I would like to see.
Spool up is nice and snappy and gets to 25 PSi quickly, then climbs to 30-31Max

comotionman

best thing you can do is put an intercooler on. will make a big difference on egt's and cooldown time.

cougar

I backed the smoke screw all the way out and still smoked/hazed bad. Added a spacer under the AFC cap to pull the fuel pin even further out. It helped a little. Most help was from a bigger turbo, but still unnerving with the sniffer police around.

oliver foster

You got the sniffers even up in Alaska?

I have all the parts for a totally stock style '91.5-'93 1st gen intercooler set up.
Or, a modified 2nd gen intercooler using the non I/Ced core support [a la sticky] swap....Maybe next winter when it is off
the road, I will look into that.

In the mean time, I figured since I wasn't towing with this truck I could get it to run cool enough / fast enough without the I/C...

I have a Denny T stage 1 pin I could add to the mix as well...maybe crank the fuel screw back and add the pin?

Any thoughts?

1972RedNeck

Put the pin in and back out of it when it gets hot.

cougar

Up until recently, then we finally got rid of them.

A stage I isn't a real aggressive pin, so if you don't get too wild with the fuel screw it will do okay. I still have the collar on my 91.5 and use the truck for towing.

Crossy's son

On a 93 D250 we had with the pump cranked the max EGT's went down 100* by cutting off the factory Dodge muffler and putting a 3" straight pipe in its place