For the people that swapped from 3.55's to 4.10's, did you notice a boost loss? I used to be able to hit 58 psi throught the power range. Now I can only hit maybe 50psi. I know that it would be easier on the motor with the lower gearing, but that seems steep. The reason I ask is the next day after I did the swap, I replaced the VP 44 and it feels like it doesnt make as much power as it did before. I dont get any codes. Replaced lift pump as well at the same time. Are there differences between 44's as far as fueling goes? Has anyone lost power by changes pumps? It seems like my old 44 was working good.

 

I would think you should be getting the same amount of boost, or very close. Might want to try hooking up to a trailer and loading it up more to see if you get back up there.

Wanna sell those 3.55's and carriers? PM me

 

The reason your not seeing as much boost is because your not loading the engine up as much with the 4.10's. It's not having to work as hard to accelerate therefore it doesn't need as much boost. As long as your EGT's stayed the same then I wouldn't worry about it.

 

more gear = less load = less boost... or so the theory goes

 

But shouldnt it be the same while towing? I am going to turn up the boost to get another 6-7 psi by putting the spacer back in on the wastegate. Any other suggestions? Anyone else do the swap and notice difference of is it just me.

 

Nope. The engine just isn't having to work as hard to accelerate. If your EGT's are the same then I wouldn't worry about upping the boost. 50psi is easier on parts than 58.

 

8 psi loss though. That seems high for just a gear swap. My temps dont get over 1300, but wont the extra boost help out for power? I thought if I turned up the boost, I would gain more power. Maybe bigger sticks again.

 

My question is--Do you like the 4:10's better?? I have been thinking about doing the same thing-losing the 3.54's for 4.10's. Then going with the 315's.

 

It depends on what you are going to do with the truck. If you tow 50% of the time, the swap is great. If you run empty most of the time, keep the 3.55's and run the 315's. You will have plenty of power, and have great rpms for economy. I tow prob at least 65% of the time. Or go get a load of sand or something. I am happy with the swap. Plus alot of guys want the 3.55's for fuel economy. I sold mine for 460 bucks. The 4.10s are cheaper. Dont know why, but I paid 200 for the gears. No carrier buy I put in lockers anyways.

 

If your temps don't get over 1300 then your not gonna gain anything by upping the boost. Your engine is burning all of the fuel that your putting into it efficiently.

 

going out on a limb here... but as I understand it, more boost doesn't make more power... that is once you are beyond the point of burning all the fuel. More air will only serve to help cool the burn.

sounds to me like you are running just fine

 

Well, maybe time for some bigger sticks. Anyone running Mach 5's?

 

Are you running the stock turbo? I don't know much about the 24v but ain't 58psi or even 50psi out of the map for the stock turbo?

 

If you are going up from 4's, you might as well skip the 5's and go to 6's. From what I've seen, they are not really any more smokey than 4's until you get into them hard. If you've got the air, you'd be fine. Just trying to keep you from making too small of steps.

 

Don't worry one bit about losing 8psi...........by swaping the gears you just free'd up a lot of power right there. Boost doesn't always mean more power, all it does is look cool on your gauge You are actually running more efficient than you were before and don't need the extra boost. Like Blue said, if your temps aren't getting out of hand I wouldn't worry about it at all.

Now the question is.........do you notice a power loss at all or just your boost numbers lower?

IMO everything is completely normal!!!


~Nick