Turned up cool running 425

It would really help to know what engine make and year you have.

 

If im not mistaken the C model 425 had a wastegated turbo. So id shim the gate a little and that will increase your boost.
Just dont pinch off the line .

Id go another turn or so and watch your temps. You can pull all day long at 900 950 tops.

If you shim the gate that will bring temps down also. Just dont push that stock turbo much over 28 psi .

 

I would start with the charge air cooler. You should get a lot more boost than 21lbs.

 

Dont forget stock spec on a 425 was 18-21 psi. But yeah , also not a bad idea to pressure test the charge air cooler.

 

Your turbo is too small. Won't put out enough air for the amount of fuel you're putting to the injectors. Although I ran a 91 KW with the stock turbo and the fuel turned up 50% for a long time and didn't have any problem with it. Just watch the pyrometer cause the only thing stopping it from melting itself on a hill is the driver. If it never goes over 9-950 shouldn't have any trouble with it I wouldn't think.

 

I don't think you have any issue with the amount of fuel if your EGT isn't above 950 unless the air to air is leaking somewhere. That would be the cheapest first thing to do would be to have it checked. If your turbo has a wastegate you could mess around with it a little by preventing it from opening all the way. Probably get you 3 or 4 more lb. of boost but if you cut it all the way off it'll probably blow a seal. I agree with the other guy. 28 lb would be a bunch of boost from a 425 stock turbo.