I'm getting ready to put an 05 turbo on my 03 and it got me to thinking.
"best of both worlds"

If you start with a 305/555 engine and put 04.5 stock parts on it, will you end up with MORE hp than the 04.5's have ?

For example..
The 04.5 four inch downpipe with the stock catless 03 exhaust.
The 04.5 stock turbo
These engines are rated only 20 hp difference, yet it has been posted that the turbo alone nets more than this, not to mention the exhaust. IF this WOULD net more hp, then does this mean the 04.5" are actually more handicapped and need the bigger turbo to make up for some of this?


THIS IS ASSUMING ALL STOCK TRUCK WITH STOCK PARTS

 

I did not see fifty horse and seventy five ft lbs I gained probaly 60HP and 74TQ between a clutch, FASS 200, five inch exhaust, and HE351 compared to stock parts using a edge with att both times on a mustang dyno so I think the benefits are lower but still better than the HE341

 

The heads are different, the pistons and different too along with the injectors, and i think the ECM is too.

 

I know that, what I am saying is this. If the 05 turbo will give an 03 engine 25 extra hp, then that puts the 03 OVER the 05 rating. Lets flip this around. If you put an 03 turbo on an 05 with a 3.5" downpipe where do we think the hp would be ??? I am assuming it would be UNDER the 305 rating.
It appears that if they BOTH had the 03 turbo, the 03 would have more power than the 05. WHY is that? Did they purposely De tune the 04.5 engine ??


Keep in mind these are not RWHP ratings

 

I believe some of the power difference is attributed to the 3rd injection event on the 04.5 on up trucks. That adds some of the power.

..

 

I must not be clear in my typing. Let me try one more thing here.

03 rating 305 hp
04.5 rating 325 hp
there is ONLY a 20 hp difference, SOOOOO... are you telling me that better injectors, bigger turbo, and better ecm/ electronics ONLY nets 20 hp ????
I've heard that the turbo ALONE nets MORE than that. SO where is the extra hp ????
If they improved the 04.5 with all these things, shouldn't the 04.5 have 40 or 50 extra horses??

 

is that what you meant?


Stock for stock without any additional fuel the 03 may gain some hp with the later turbo being installed and exhaust change due to the slight increase in air flow but without extra fueling to take advantage of it's the additional compressor capacity the net gain would be minimal since there are no additional BTU's being produced.

So stock for stock with no compensentory fueling i dont think the HP gain will be above 20hp.

 

I agree. Without the extra fuel the gain with the larger turbo will be very minimal.

MikeyB

 

Exactly... Stock fueling you will not see that big of a gain, all you will see is cooler EGTs. The HE351 allows for more fueling than the stock 03 turbo does, so if provides a good increase from the cooler, denser air.

And the 04.5 may be "slightly" handicapped, as its a 50 state motor and the 305 motor is not.

 

I've heard that nonsense before! We'll have to just test that theory some time at the track.



....but to answer the original posters question, no the truck wont be as powerfull/fast. The 3rd injection even provides....well I guess more fuel! You'll get more out of programming as well when you put power adders on. Now I dont think they are a bad engine, as they do have their advantages, and can be built to be just as fast.

 

Bring it on Boss! I heard you couldn't even whoop your other buddy down the street.

..